CA1092271A - Preparation of high concentration dispersions of cross-linked acrylic polymer microparticles - Google Patents
Preparation of high concentration dispersions of cross-linked acrylic polymer microparticlesInfo
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- CA1092271A CA1092271A CA298,122A CA298122A CA1092271A CA 1092271 A CA1092271 A CA 1092271A CA 298122 A CA298122 A CA 298122A CA 1092271 A CA1092271 A CA 1092271A
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Abstract
ABSTRACT
Crosslinked acrylic polymer microparticles having a particle size of from 0.1 to 10 microns are produced in relatively high con-centrations by a method comprising the free radical addition copolymeri-zation of at least one ethylenically-unsaturated monomer with an alpha, beta-ethylenically unsaturated monocarboxylic acid and a crosslinking monomer selected from the group consisting of epoxy group-containing compounds, or a mixture of alkylenimine and organoalkoxysilane in the presence of a dispersion stabilizer and a dispersing liquid in which the cross-linked polymer particles are insoluble.
These crosslinked polymeric microparticles can be blended with various resins to produce compositions having improved application characteristics as well as other desirable properties.
Crosslinked acrylic polymer microparticles having a particle size of from 0.1 to 10 microns are produced in relatively high con-centrations by a method comprising the free radical addition copolymeri-zation of at least one ethylenically-unsaturated monomer with an alpha, beta-ethylenically unsaturated monocarboxylic acid and a crosslinking monomer selected from the group consisting of epoxy group-containing compounds, or a mixture of alkylenimine and organoalkoxysilane in the presence of a dispersion stabilizer and a dispersing liquid in which the cross-linked polymer particles are insoluble.
These crosslinked polymeric microparticles can be blended with various resins to produce compositions having improved application characteristics as well as other desirable properties.
Description
~U9ZZ71 This application ls a dlvisional of Serial Number 243,461 filed 13 January, 1976 and is directed to the gelled polymeric microparticles and method of preparation while specific compositlons containing the microparticles are the sub;ect of Serial Number 243,461.
Background of The Invention Methods of preparing crosslinked polymeric microparticles commonly ::
referred to as microgel particles are known in the art. One such method is disclosed in commonly-assigned copending Canadian application Serial No.
180,828 filed 12 September, 1973, in the name of Roger M. Christenson et al.
In this method, a non-aqueous polymer dispersion is prepared by polymerizing an ethylenically-unsaturated monomer containing hydroxyl groups in the presence of (1) a dispersing liquid which is a solvent for the monomer but in which the resultant polymer is insoluble and ~2) a dispersion stabilizer.
The resultant non-aqueous .~
polymer dispersion produced by this metll~d consists of a major pro-portion of uncrosslinked polymer particles and a minor proportion (e.g., 10 percent by weight or less) of crosslinked polymer particles (i.e., microgel particles). Accordingly, in this method, it is necessary to separate the microgel particles from the uncrosslinked polylllcr particles. This is accomplished by the addition to the dis-persion o~ an active solvent for the uncrosslinked polymer particles, ther~by converting the dispersion to essentially a solution, but for the presence of the insoluble microgel particles. The microgel pnrticles are then separated from the bulk of the polymer by conventional means SllCh as centrifuging, filtering, and the like.
The above process, while advantageous in some respects, llas several serious disadvantages. Thus, as will be apparent, the micro-gel particles are an incidental by-product of the non-aqueous dispersion process and therefore the yield is relatively low (e.g., 5 to lO per-cent by wei~ht or less). Moreovcr, because oE this factor, it is nece~sary to separate the microgel particles from a dispersion which contains a major proportion of uncrosslinked polymer particles by dissolving the ul~crosslinked polymer particles with an active solvent.
Still another method for producing microgel particles is disclosed in British Patent No. 967,051 to Bullitt et al, dated August 19, 1964. In this method, microgel particles are prepared by forming an aqueous emulsion of monoethylenic unsaturated monomer and a crosslinking monomer containing at least two ethylenic double bonds, heating the emulsion to a temperature of about 40 to 100C. until the reaction is substantially complete to yield a microgel and during the re;lctioll addillg an agent to inhibit the formation of high molecular ;~
. . .
-~09ZZ71 weight substantially uncrosslinked material. The inhibiting agent as disclosed in Bullitt et al can be an active solvent for the monomers or a chain transfer agent. This method has several disadvantages.
Thus, the method utilizes conventional emulsion polymerization tech-niques requiring careful control of the process to prevent settling and the like. Further, the use of crosslinking monomers containing at least
Background of The Invention Methods of preparing crosslinked polymeric microparticles commonly ::
referred to as microgel particles are known in the art. One such method is disclosed in commonly-assigned copending Canadian application Serial No.
180,828 filed 12 September, 1973, in the name of Roger M. Christenson et al.
In this method, a non-aqueous polymer dispersion is prepared by polymerizing an ethylenically-unsaturated monomer containing hydroxyl groups in the presence of (1) a dispersing liquid which is a solvent for the monomer but in which the resultant polymer is insoluble and ~2) a dispersion stabilizer.
The resultant non-aqueous .~
polymer dispersion produced by this metll~d consists of a major pro-portion of uncrosslinked polymer particles and a minor proportion (e.g., 10 percent by weight or less) of crosslinked polymer particles (i.e., microgel particles). Accordingly, in this method, it is necessary to separate the microgel particles from the uncrosslinked polylllcr particles. This is accomplished by the addition to the dis-persion o~ an active solvent for the uncrosslinked polymer particles, ther~by converting the dispersion to essentially a solution, but for the presence of the insoluble microgel particles. The microgel pnrticles are then separated from the bulk of the polymer by conventional means SllCh as centrifuging, filtering, and the like.
The above process, while advantageous in some respects, llas several serious disadvantages. Thus, as will be apparent, the micro-gel particles are an incidental by-product of the non-aqueous dispersion process and therefore the yield is relatively low (e.g., 5 to lO per-cent by wei~ht or less). Moreovcr, because oE this factor, it is nece~sary to separate the microgel particles from a dispersion which contains a major proportion of uncrosslinked polymer particles by dissolving the ul~crosslinked polymer particles with an active solvent.
Still another method for producing microgel particles is disclosed in British Patent No. 967,051 to Bullitt et al, dated August 19, 1964. In this method, microgel particles are prepared by forming an aqueous emulsion of monoethylenic unsaturated monomer and a crosslinking monomer containing at least two ethylenic double bonds, heating the emulsion to a temperature of about 40 to 100C. until the reaction is substantially complete to yield a microgel and during the re;lctioll addillg an agent to inhibit the formation of high molecular ;~
. . .
-~09ZZ71 weight substantially uncrosslinked material. The inhibiting agent as disclosed in Bullitt et al can be an active solvent for the monomers or a chain transfer agent. This method has several disadvantages.
Thus, the method utilizes conventional emulsion polymerization tech-niques requiring careful control of the process to prevent settling and the like. Further, the use of crosslinking monomers containing at least
2 ethylenic double bonds (e.g., divinyl and diacrylate monomers) has been found to lead to flocculation problems in relatively high solids level ~i.e. 40 percent by weight or higher) microgel particle dispersions.
Finally, this method requires the additional step of adding a water-immiscible solvent or chain transfer agent to the reaction mixture.
The method of the present invention overcomes essentially all of the disadvantages of the prior art. Thus, the present invention provides a method of producing crosslinked acrylic polymer microparticles of from 0.1 to 10 microns particle size in relatively high concentrations ~i.e.
solids levels of 20 to 60 percent by weight) by a process which comprises the free radical addition copolymerization of from about 0.5 to 15 ; percent of an alpha, beta-ethylenically unsaturated monocarboxylic acid with from about 70 to 99 percent of at least one other ethylenically ` 20 unsaturated monomer and from about 0.5 to 15 percent of a crosslinking monomer selected from the group consisting of ~1) epoxy group-containing compounds, ~2) a mixture of alkylenimine and organoalkoxy-silane, wherein a. said epoxy group-containing compound is monoepoxide compound which additionally contains ethylenic unsaturation, b. said organoalkoxysilane is selected from the group con-sisting of acrylatoalkoxysilane, methacrylatoalkoxysilane and vinylalkoxysilane, and c. said monomer percentages are based on the weight of monomers used in the copolymerization process, _3_ A'i , ,, .. ,.. _, , ', .
.
in the presence of hydrocarbon dispersing liquid which is a solvent for the polymerizable monomers but a non-solvent for the resultant polymer, and polymeric dispersion stabilizer containing at least two segments o which one segment is solvated by said dispersing liquid and a second segment is of different polarity than said first segment and is relatively insoluble in said dispersing liquid, wherein the reaction i5 carried out at elevated temperature such that the dispersion polymer first forms and then is crosslinked. Usually the temperature of reaction should be between about 50 C and 150 C.
The crosslinked acrylic polymer microparticles resulting from the method of this invention can be blended with resins such as polyurethanes, -3a-¦ ~A~
. . .
. . , . ., .
,. . . .. . . .... . . ~ ,.
.. ... . .
lO9ZZ7~
polyesters and the like to produce coating compositions having improved application characteristics and other desirable properties Description of the Preferrcd Embodiments The preferred alpha, beta-ethylenically unsaturated mono-carboxylic acids employed in the process of this invention are acrylic and methacrylic acid. ~lowever, other ethylenically unsaturated carboxylic acids such as ethacrylic acid, crotonic acid, and half esters of maleic and fumaric acids may also be used. In the half esters, one of the carboxyl groups is esterified with an alcohol, the identity of which is not significant so long as it does not prevent polymerization or preclude the desired utilization of the product. BuLyl hydrogell maleate and ethyl hydrogen fumarate are examples.
From about 0.5 to about 15.0 percent by weight of such acid monomers based on the weight of monomer solids is employed in the process of the invention.
Various other ethylenically unsaturated monomérs may be co-polymerized with tl-e acid monomer and crosslinking monomers in the process of tl-is invention. Although essentially any copolymerizable ethylenic monomer may be utilized, depending upon the properties desired io the preferred ethylenically-unsaturated monomers are the alkyl esters of acrylic or methacrylic acid, particularly those having from about 1 to about 4 carbon atoms in the alkyl group. Illustrative of such com-pounds are the alkyl acrylates, such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate and the alkyl methacrylates, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate. Other ethylenically unsaturated monomers which ~A 1 ~ ~ .
.
~09ZZ71 may advantageously be employed include, for example, the vinyl aromatic hydrocarbons, such as styrene, alpha-methyl styrene, vinyl toluene, unsaturated esters of organic and inorganic acids, such as vinyl acetate, vinyl chloride and the like, and the unsaturated nitriles, such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like. From about 70 percent to about 99 percent by weight of such ethylenically unsaturated monomers, based on the weight of monomer solids is utilized.
As indicated above, the crosslinking monomers employed in the process of the invention are selected from the group consisting of epoxy group-containing compounds, or a mixture of alkylenimine and organo-alkoxysilane.
.
~1 ... , .. ,. ,,, ,. ,, . , ,, ., ., ,..... " ~ ... . .. . . ..
lO9ZZ'71 The epoxy group-containin~ compounds which may be utilized in the practice of the invention are monoepoxlde compounds which additionally contain ethylenic unsaturation. Illustrative of such compounds are, for example, glycidyl acrylate and glycidyl methacrylate.
Various alkylenimines can be utilized in the practice of the invention including substituted alkylenimines. The preferred class of SUCIl amines are those of the formula:
,2 6 ,3 Rl - C - (C~l) j C - R4 N
where 1~1~ R2, 1~3, R4 and R5 are eacllllydrogen; alkyl, sucll as metllyl, ethyl, propyl or the like, having, for example, up to about ~0 earbon atoms; aryl, such as phenyl or the like; aralkyl, such as tolyl, xylyl or tlle like; or aralkyl, such as benzyl, phenethyl or the like. K6 in the above formula is hydrogen or a lower alkyl radical u~ually having not more than about 6 carbon atoms, and n is an integer from 0 to 1.
- It is intended that the groups designated by the above formula include substituted radicals of the classes indicated where the sub-stituent groups do not adversely affect tlle basic nature of the imine in the reactioll. Such substituents can include the groups such as eyano, halo, amino, hydroxy, alkoxy, carbalkoxy and nitrile. The substituted groups may tl-us be cyanoalkyl, haloalkyl, amilloalkyl, llydroxyalkyl, alkoxyalkyl, carbalkoxyalkyl, and si~llilar substituted derivatLv~s of aryl, alkaryl and aralkyl groups where present.
. , .
.
, -~ lOgZZ71 A number of specific examples of alkylenimines within the c:lass clescribed are as follows:
Etllylenillline (aziridine) 1,2-propylenimine (2-methyl aziridine) 1,3-propylenimine (azetidine) 1,2-dodecylenimine (2-decyl aziridine) I,l-dimethyl etllylanimine (2,2-dimethyl aziridine) Pllenyl ethylenimine (2-phenyl aziridine) Bcnzyl etllylenillline (2-phenylmetllyl aziridinc) llydroxyetllyl etllylenimine (2-(2-hydroxyetllyl)aziridine) ~minoethyl ethylellimine (2-(2-aminoethyl)aziridine) 2-metllyl propylellimine (2-methyl azetidine)
Finally, this method requires the additional step of adding a water-immiscible solvent or chain transfer agent to the reaction mixture.
The method of the present invention overcomes essentially all of the disadvantages of the prior art. Thus, the present invention provides a method of producing crosslinked acrylic polymer microparticles of from 0.1 to 10 microns particle size in relatively high concentrations ~i.e.
solids levels of 20 to 60 percent by weight) by a process which comprises the free radical addition copolymerization of from about 0.5 to 15 ; percent of an alpha, beta-ethylenically unsaturated monocarboxylic acid with from about 70 to 99 percent of at least one other ethylenically ` 20 unsaturated monomer and from about 0.5 to 15 percent of a crosslinking monomer selected from the group consisting of ~1) epoxy group-containing compounds, ~2) a mixture of alkylenimine and organoalkoxy-silane, wherein a. said epoxy group-containing compound is monoepoxide compound which additionally contains ethylenic unsaturation, b. said organoalkoxysilane is selected from the group con-sisting of acrylatoalkoxysilane, methacrylatoalkoxysilane and vinylalkoxysilane, and c. said monomer percentages are based on the weight of monomers used in the copolymerization process, _3_ A'i , ,, .. ,.. _, , ', .
.
in the presence of hydrocarbon dispersing liquid which is a solvent for the polymerizable monomers but a non-solvent for the resultant polymer, and polymeric dispersion stabilizer containing at least two segments o which one segment is solvated by said dispersing liquid and a second segment is of different polarity than said first segment and is relatively insoluble in said dispersing liquid, wherein the reaction i5 carried out at elevated temperature such that the dispersion polymer first forms and then is crosslinked. Usually the temperature of reaction should be between about 50 C and 150 C.
The crosslinked acrylic polymer microparticles resulting from the method of this invention can be blended with resins such as polyurethanes, -3a-¦ ~A~
. . .
. . , . ., .
,. . . .. . . .... . . ~ ,.
.. ... . .
lO9ZZ7~
polyesters and the like to produce coating compositions having improved application characteristics and other desirable properties Description of the Preferrcd Embodiments The preferred alpha, beta-ethylenically unsaturated mono-carboxylic acids employed in the process of this invention are acrylic and methacrylic acid. ~lowever, other ethylenically unsaturated carboxylic acids such as ethacrylic acid, crotonic acid, and half esters of maleic and fumaric acids may also be used. In the half esters, one of the carboxyl groups is esterified with an alcohol, the identity of which is not significant so long as it does not prevent polymerization or preclude the desired utilization of the product. BuLyl hydrogell maleate and ethyl hydrogen fumarate are examples.
From about 0.5 to about 15.0 percent by weight of such acid monomers based on the weight of monomer solids is employed in the process of the invention.
Various other ethylenically unsaturated monomérs may be co-polymerized with tl-e acid monomer and crosslinking monomers in the process of tl-is invention. Although essentially any copolymerizable ethylenic monomer may be utilized, depending upon the properties desired io the preferred ethylenically-unsaturated monomers are the alkyl esters of acrylic or methacrylic acid, particularly those having from about 1 to about 4 carbon atoms in the alkyl group. Illustrative of such com-pounds are the alkyl acrylates, such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate and the alkyl methacrylates, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate. Other ethylenically unsaturated monomers which ~A 1 ~ ~ .
.
~09ZZ71 may advantageously be employed include, for example, the vinyl aromatic hydrocarbons, such as styrene, alpha-methyl styrene, vinyl toluene, unsaturated esters of organic and inorganic acids, such as vinyl acetate, vinyl chloride and the like, and the unsaturated nitriles, such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like. From about 70 percent to about 99 percent by weight of such ethylenically unsaturated monomers, based on the weight of monomer solids is utilized.
As indicated above, the crosslinking monomers employed in the process of the invention are selected from the group consisting of epoxy group-containing compounds, or a mixture of alkylenimine and organo-alkoxysilane.
.
~1 ... , .. ,. ,,, ,. ,, . , ,, ., ., ,..... " ~ ... . .. . . ..
lO9ZZ'71 The epoxy group-containin~ compounds which may be utilized in the practice of the invention are monoepoxlde compounds which additionally contain ethylenic unsaturation. Illustrative of such compounds are, for example, glycidyl acrylate and glycidyl methacrylate.
Various alkylenimines can be utilized in the practice of the invention including substituted alkylenimines. The preferred class of SUCIl amines are those of the formula:
,2 6 ,3 Rl - C - (C~l) j C - R4 N
where 1~1~ R2, 1~3, R4 and R5 are eacllllydrogen; alkyl, sucll as metllyl, ethyl, propyl or the like, having, for example, up to about ~0 earbon atoms; aryl, such as phenyl or the like; aralkyl, such as tolyl, xylyl or tlle like; or aralkyl, such as benzyl, phenethyl or the like. K6 in the above formula is hydrogen or a lower alkyl radical u~ually having not more than about 6 carbon atoms, and n is an integer from 0 to 1.
- It is intended that the groups designated by the above formula include substituted radicals of the classes indicated where the sub-stituent groups do not adversely affect tlle basic nature of the imine in the reactioll. Such substituents can include the groups such as eyano, halo, amino, hydroxy, alkoxy, carbalkoxy and nitrile. The substituted groups may tl-us be cyanoalkyl, haloalkyl, amilloalkyl, llydroxyalkyl, alkoxyalkyl, carbalkoxyalkyl, and si~llilar substituted derivatLv~s of aryl, alkaryl and aralkyl groups where present.
. , .
.
, -~ lOgZZ71 A number of specific examples of alkylenimines within the c:lass clescribed are as follows:
Etllylenillline (aziridine) 1,2-propylenimine (2-methyl aziridine) 1,3-propylenimine (azetidine) 1,2-dodecylenimine (2-decyl aziridine) I,l-dimethyl etllylanimine (2,2-dimethyl aziridine) Pllenyl ethylenimine (2-phenyl aziridine) Bcnzyl etllylenillline (2-phenylmetllyl aziridinc) llydroxyetllyl etllylenimine (2-(2-hydroxyetllyl)aziridine) ~minoethyl ethylellimine (2-(2-aminoethyl)aziridine) 2-metllyl propylellimine (2-methyl azetidine)
3-chloropropyl ethylenimine (2-(3-chloropropyl)aziridine) Metlloxyethyl etllylenimine (2-(2-methoxyethyl)aziridine) Dodecyl aziridinyl ~ormate (dodecyl l-aziridinyl carboxylate) N-etllyl ethylenimine (l-ethyl aziridine) N-(2-aminoetllyl)ethylenimine (1-(2-aminoethyl)aziridine) N-(pllenethyl)etllylenimine (1-(2-pllenyletllyl)aziridine N-(2-hydroxyetllyl)etllylenimine (1-(2-hydroxyethyl)aziridine) N-(cyanoethyl)ethylenimine (l-cyanoethyl aziridine) N-phenyl cthylenimine (l-phenyl aziridine) N-(p-chlorophenyl)etllylenimine (1-(4-chlorophenyl)aziridine) Because of their availability and because they have been found to bc among tllc most effective, thc prefc~rred imines are llydroxyalkyl-substitutcd alkylcnimines, such as N-hydroxyetllyl ethylenimine and N-Ilydroxye~llyl propylcnimine.
,. : ,. ' ,. . : :
` ' ' .: : `' .` :
~9ZZ~l Organoalkoxysilane monomers wl-ich are employed in the practice of this invention are the acrylatoalkoxysilanes, mcthacrylatoalkoxysi]anes and the vinylalkoxysilanes. Illustrative of sucll compounds are acryloxypropyltrimethoxysilalle, gamma-mctil-acryloxypropyll::rimetlloxysilane, gamma-methacryloxypropyltriethoxysilane, gamma-mctllacryloxypropyl-tris(2-methoxycthoxy)silane, vinyltrimethoxy-silane, vinyltrietlloxysilane, vinyl-tris(2-mcthoxyethoxy)silane and thc like. Of thcse organoalkoxysilanes, gamma-methacryloxypropyltri-metl~oxysilane is especially preferred.
The proportion of such crosslinking monomers employed in the proccss of ~he invention may range from 0.5 perccnt Lo 15 perccnt by weight.
The cthylenically-unsaturated monomer, acid monomer and cross-linking monomer are polymerized in a dispersing liquid whicll solubilizes the monomers but in whicll the resulting polymers are cssentially not soluble and form dispersed polymer particles. The non-solvent is a hydrocarbon medium consisting essentially of liquid ali- ;
phatic hydrocarbons. A pure aliphatic hydrocarboll or a mixture of two or more may be employed. To the extent that any particular polymer produced is mostly insoluble in the hydrocarbon mcdium rcsulting, the essentially aliphatic hydrocarbon may be modified by the incorporation of other solvcllt materials such as aromatic or naphthenic hydrocarbons, and in ccrtain instances the amount of such non-aliphatic component may atLain as high as 49 percent by weight of the cntire liquid medium.
owever, the liquid medium preferably consists essenLially of aliphatic hydrocarbons and, in general, the compositions of the present invention contain less than ~5 perccnt by wcight bascd on the weight of the liquid medium of an aromatic hydrocarbon an~ often none at all at this stage.
~;
_,, . , .. _ . .... . .. . , . _ _ .
lO9ZZ~l It is essential that the hydrocarbon be of liquid character, but it may bave a wide boiling range from a minimum of about 30C. (in wl~icll case higll pressures may be necded in the polymerization) to a maxilllu~ icll may be as higll as 300C. Ior most purposes, the boiling point should be Lrom about 50C. Up to about 235C.
Examples of non-solvents useful herein are pentane, hexane, heptane, ocLanc, mixtures of thc same, and the lilie.
Ordinarily, the polymerizable composition of monomcrs and non-solvent should contain from about 30 to about 80 percent by weight o~ the non-solvcnt. It is undcrstood, however, that the monomeric solution need contain only that amount of non-solvent necessary to solubilize the monomers and maintain the resulting polymers in a dis- -persed state aftcr polymerization.
The monomers arc polymerized in the presence of a dispersion stabilizer. The dispersion stabilizer employed in producing the micro-particles of the invention is a compound, usually polymeric, which contains at least two segments of which one segment is solvated by the dispcrsing liquid and a second segment is of different polarity than the first segment and is relatively insoluble (compared to the first segment) in the dispersing liquid. Although such compounds have been used in the past to prepare dispersions of polymer, in those installces it has been considered necessary tllat the polymer produced be ungelled, film-forming and soluble in certain solvents.
~ ncludcd among such dispersion stabilizers are polyacrylates and polymetllacrylates, such as poly(lauryl)methacrylate and poly(2-ethyl-hexyl acrylate); diene polymers and copolymers such as polybutadiene and degraded rubbers; aminoplast resins, particularly higllly naphtlla-tolerant compounds such as mclamine-formaldehyde resins etherified ` 109ZZ71 with hi~ller alcohols (e.g., alcohols having 4 to 12 carbon atoms), for example, butanol, hexanol, 2-ethylllexallol, etc., and other aminoplasts of similar characteristics such as certain resins based on urea, benzo-guallamille, and the like; and various copolymers dcsigned to have the desired char.lcteristics, for example, polyethylene vinyl acetate co-polymers .
Illc presently prererred dispcrsion stabilizcrs used in thisinventioll are graft copolymers comprising two types of polymer components of wllich one segment is solvated by the aliphatic hydrocarbon solvent and is usually not associated with polymerized particles of the poly- --merizable ethylenically-unsaturated monomer and the second type is an anchor polymer of different polarity from the first type and being relativcly non-solvatable by tlle aliphatic hydrocarbon solvent and capable o~ anchoring with the polymerized particles of the ethylenically unsat~lrated monomer, said anchor polymer containing pendant eroups - -capal-le of copolymerizing with etllylenically-unsaturated monomers.
The preferred dispersion stabilizers are comprised of two segments. The first segment (A) comprises the reaction product of (1) a long-chain hydrocarbon molecule which is solvatable by the dispersing liq~id and contains a terminal reactive group and (2) an ethylenically-unsaturated compound wllicll is copolymeri~able with the ethylenically unsaturated monomer to be polymerized and which contains a functional ~roup capable of reacting with the terminal reactive group of the long-chain hydrocarbon molecule (1).
Generally, the solvatable segment (~) is a monofunctional polymerlc material of molecular weight of about 300 to about 3,000.
Thcse polymcrs may be madc, for example, by condensation reaction producin~ ~ polyester or polyether. The most conveniellt monomers to . ' .
~(~9ZZ71 use are hydroxy acids or lactones wllich form hydroxy acid polymers.
lor example, a hydroxy fa~ty acid sucll as 12-llydroxystearic acid may be polymerized to form a non-polar component solvatable by such non-polar organic liquids as aliphatic and aromatic hydrocarbons. The polyhydroxy stearic acid may then be reacted with a compound which is eopolymerizable witl- the acrylic monomer to be polymerized, such as glycidyl acrylate or glycidyl methacrylate. The glycidyl group would react witll the carboxyl groups of tlle polyllydroxy stearic acid and the polymer segment (A) would be formed.
Somewhat more complex, but still useful, polyesters may be made by reacting diacids with diols. For example, 1,12-dodecanediol may be reaeted with sebaciC acid or its diacid chloride to form a component solvatable by aliphatic hydrocarbons.
The preferred polymeric segment (A) of tl-e dispersion stabilizer is formed by reacting poly-(12-hydroxystearic acid) with glycidyl meth-....
acrylate.
Tlle second polymeric segment (B) of the dispersion stabilizeris of polarity different from the first segment (A) and, as such, is relatively non-solvated by the dispersing liquid and is associated with or eapable of anchoring onto tlle acrylic polymeric particles formed by the polymerization and contains a pendant group which is copolymerizable with the acrylic monomer. This anchor segment (B) provides around the polymerized particles a layer of the stabilizer. The solvated polymer ~egmenC (A) which extends outwardly from the surface of the partieles provi(les a solvated barrier wl-ieh sterieally stabilizes the polymerized particles in dispersed form.
rhe anchor segment (B) may eomprise copolymers of (1) compounds whleh .~re rea~lily associated Witll the acrylic mononler to be polymerized ' _ Ll _ .. .. . .
such as acrylic or methacrylic esters, such as methyl acrylate, methyl metllacrylatc, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl metllacrylate, 2-ethylllexyl acrylate, octyl methacrylate, and the like, wiLh (2) compounds ~hich contain groups copolymerizable with the acrylic monomer to be polymerized and which contain groups which are reactive witll the polymeric segment (A), such as glycidyl-containing acrylates and mctl-acrylatcs, such as glycidyl acrylate and glycidyl methacrylate.
These copolymers are further reacted with polymerizable ethylenically-unsnturated acids, such as acrylic acid, methacrylic acid, 3-butenoic acid, crotonic acid, itaconic acid, and others mentioned previously which contain pendant groups which are copolymerizable with the acrylic monomer.
The preferred polymeric segtnent (~) is a terpolymer of methyl methacrylate, glycidyl methacrylate, and methacrylic acid.
The segments (~) and (B) are usually combined entities, the segment (A) being attached to the backbone of the graft copolymer and the segment (~) being carried in or on the backbone.
The mollomer solution containing the stabilizer preferably con-tains from about 1 to about 25 percent by weight of the stabilizer.
; Tlle polymerization may be carried out in a conventional manner, utilizing heat and/or catalysts and varying solvents and techniques.
Cenerally, a free radical catalyst such as cumene hydroperoxide, benzoyl peroxide or similar peroxygen compound, or an azo compound such as azo-bisisobutyronitrile is employed. ~ :
The resultant non-aqueous acrylic dispersion CollSiStS ess-entially of microgel particles (i.e., crosslinked polymer particles) dispersed therein. These particles have particle sizes ranging from 0,1 to 10 microns. Depending upon the original concentration of ,: . . ' '. .. ` ' ' ' ~ `: ' ' :
~" 109ZZ71 monomer solids, non-aqueous dispersions consisting essentially of the microgel particles can be produced by the process at relatively hi~h conccntrations. The term "relatively high concentration" as employed llerein refers to tl~e solids level of the non-aqueous dispersion. Thus, the proccss of this invention permits the production of non-aqueous dispcrsions of microgel particles having solids contents of from 20 to 60 percent by weight or even higher.
As mentioned above, the gelled polymeric micropartlcles pre-pared by the proccss, can be blended with various resins such as poly-urethanes, polyesters and the like to produce coating compositions having improved application characteristics and other desirable properties.
Thus, by blending these gelled polymeric microparticles in appropriate quantities with resins of the above type, coating compositions can be obtained whicll upon application exhibit improved f ilm build, metallic pattern control and flow control. Moreover, these improved character-istics can be obtained without adversely affecting the gloss of films formed from the resultallt coating compositions. A particularly sig-nificant improvement obtained when these gelled polymeric microparticles are included in a coating composition is as indicated in the area of film build, particularly the film build of compositions utilized as topcoat materials in the automotive industry. Heretofore, most commercial topcoat compositions for use in the automotive industry -when spray applied often required at least three spray coats to obtain films havlng the desired thickness. By including an appropriate quantity of the ~elled polymeric microparticIes produced in tllis invention in --sucll topcoaL compositions, the same thickness can be obtained in two spray coats.
' ' ''' :'' -, lO9ZZ71 Polyurethane coating compositions having the improved appli-cation characteristics and other desirable properties can be obtained by blending the crosslinked acrylic polymer microparticles with an iso-cyanate modified resin containing hydroxyl groups, formed by reacting a polyhydric material with an organic polyisocyanate, and, if desired, curing agents and other additives.
The polyhydric material preferably contains a polymeric polyol sucll as a polyether polyol, a polyester polyol, or an acrylic polyol. The polymcric polyol sh~uld be predominalltly linear (that is, absence of crosslinks) to avoid gelling of the resultant polymeric product and should have a molecular weight of between 500 and 5000.
As exampl:es of polyether polyols, any suitable polyalkylene ether polyol may be used including those which have the following strucLural formula:
m where R is hydrogen or lower alkyl and n is typically from 2 to 6 and m is from 2 to 100 or even higher. Included are poly(oxytetramethylene) glycols, poly(oxyethylene)glycols, poly(oxytrimethylene)glycols, poly (oxypentamethylene)glycols, polypropylene glycols, etc. ~Lso useful are polyethcr polyols formed from the oxyalkylation of various polyols, for example, glycols &uch as ethylene glycol, 1,6-hexanediol and the likc, or highcr polyols, such as trimethylol propane, trimethylolethane, pentaerythritol and the like. Polyols of higller functionality which can be utilizcd as indicated can be made, for instance, by oxyalkylation of compounds a5 ~orbitoL or sucro~e.
S'- , ~ 14 -~- 1092271 Also suitable are polyby(lric po]ythioether such as, for example, tlle condensation product of thioglycol or the reaction product of a polyhydric alcohol with thioglycolic or any other suitable glycol.
Polyester polyols can also be used as a polymeric polyol component in making the polyurethane resin. Such polyester polyols --calt be prepared by the polyesterif ication of organic polycarboxylic acids or anhydrides thereof with organic polyols. Usually, the poly-cnrboxylic acids and polyols are alipllatic or aromatic dibasic acids and diols, although a minor amount, i.e., up to about 25 mole percent of polyols and polybasic acids having a functionality of 3 or more, can be used. Ilowever, the use of higher functionality polybasic acids anù polyols must be carefully controlled so as to avoid gelling in the resultant polymeric product. Diols which are usually employed in making the polyester include alkylene glycols, such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol and neo- -pentyl glycol and other glycols such as hydrogenated Bisphenol A, cyclohexane dimetllanol, caprolactone diol (for example, the reaction product of caprolactone and ethylene glycol), hydroxyalkylated bis-phenols, polyether glycols, for example, poly(oxytetrametllylene)glycol and the like. Ilowever, other diols of various types and, as indicated, --polyols of higher functionality can also be utilized, including for example, trimethylol propane, trimethylol ethane, pentaerythritol, and the likc, as well as higher molecular weight polyols such as those produceù by oxyalkylating low molecular weight polyols.
The acid component of the polyester conslsts primarily of monomeric carboxylic acids or anhydrides having 2 to 14 carbon atoms pcr m~lecllle. Tlle acld sho-lld have an average [ullctionlllity of at lOgZZ71 least about 1.9; the acid component in most instances contains at least 75 mole percent of dicarboY.ylic acids or anhydrides Tlle functionality of the acid component is based upon considerations similar to those discussed above in connection with the alcohol component, the to~al functionality of the system being kept in mind.
Among the acids whicll are useful are phthalic acid, iso-phtllalic acid, terephthalic acid, tetrahydrophthalic acid, hexa-hydrophtllcllic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, glutaric acid, chlorendic acid, tetrachlorophthalic acid, and otller dicarboxylic acids of varying types. The polyester may include --minor amounts of monobasic acid, SUCll as benzoic acid, and there may also be employed l~igller polycarboxylic acids such as trimellitic acid and tricarballylic acid (where acids are referred to above, it is understood that the anhydrides of those acids whicll form anhydrides can be used in place of the acid3. It is preferred that the polyester include an aliphatic dicarboxylic acid as at least part of the acid component.
The polyester polyols useful herein also include polyester amide polyols, and polyhydric compounds having polyester structures but not fonned from the reaction of an alcohol and an acid. Examples of this latter type include the so-called lactone polyesters, such as polycaprolactone polyols, as described in U.S. Patent 3,169,945 to llostettler et al.
Besides polyether and polyester polyols, useful polyoIs in-clude hy~roxyl-containing interpolymers of ethylenically unsaturated --monomers. I'xamples o ~uch interpolymers are the so-called acrylic polyols, which include interpolymers of a hydroxyalkyl ester of an ethylenlcally unsaturated carboxylic acid and one or more copolymeri~able ethylenically unsaturated compounds.
- l6 -lO9Z271 The preferred in~crpolymers are those containing hydroxy groups dcrivcd fro~ 0noacrylates or mctl~acry]atcs of a diol such as llydroxyalkyl acrylates and metllacrylates. Ixamples include acrylic acid and methacrylic acid esters of ethylene glycol and 1,2-propylene glycol such as hydroxyetllyl acrylate and methacrylate and hydroxy-propyl methacrylate as well as polyethylene glycol monoacrylate and polycal)rolaccone diol or polyol monoacrylate. ~Iydroxybutyl acrylate, llydroxyoc~yl methacrylate, and the like are further examples of the llydroxy.lll;yl estcrs of tlle interpolymer. ~lso useful are the hydroxy-containing esters of such unsaturated acids as maleic acid, fumaric acid, itaconic acid, and tlle like. Tlle hydroxyalkyl ester is inter-polymerized with any ethylenically unsaturated compound copolymerizable witll the ester, the polymerization taking place througll tlle ethylenlcally unsaturated linkagcs; acrylic monomers and vinyl aromatic hydrocarbon monomers are often utilized. Functional monomers, such as acrylamide, N-alkoxyalkyl acrylamides and masked or blocked ethylenically unsaturated isocyanates may also be used.
One particularly preferred class of acrylic polyols comprises in`terpolymers of hydroxyethyl acrylate or metllacrylate, one or more `~
lower alkyl acrylates and, if desired, an unsaturated nitrile and an N-alkoxymethyl acrylamide.
Besides polymeric polyols, low molecular weight polyols, that is tllosc having molecular weights up to 250, can be employed as part or all of the polyhydric material. The low molecular weight polyols incllldc diols, triols an(l higllcr alcohols. Sucll matcrials include alipllatic polyols particularly alkylene polyols containing from about 2 to lS carbon atoms. Examples include ethylelle glycol, 1,2-propancdiol, 1,4-butanedlol, 1,6-1lexanediol, 2-methyl-1,3 pentancdiol; cycloaliphatic .
, , .-: : , , , i , ,, , , :
polyols such as 1,2-cyclohexanediol, 1,2-bis(hydroxyrnethyl)cyclohexane and cyclohexane dimcthanol. Examples of triols and higher alcohols include trimethylol propane, trimethylol ethane, glycerol and pen-taerythritol. ~lso useful are polyols containing ether linkages such as diethylene glycol, and triethylene glycol.
To producc optimum coatings, the overall functionality per unit weigllt of the reaction system should be controlled. Preferably, there should not be present more than about one gram-mole of acids and/or alcohols having a functionality of 3 or more, per 500 grams of tlle total weight of these compounds. By "functionality" is meant the number of reactive hydroxyl and carboxyl groups per molecule, with anhydride groups being considered as equivalent to two carboxyl groups.
It can be noted that certain compounds contain both hydroxyl and car-boxyl groups; examples are 6-hydroxyhexanoic acid, 8-hydroxyoctanoic acid, tartaric acid, etc.
The organic polyisocyanate which is reacted with the poly-hydric material as described is e.sscntially any polyisocyanate, e.g., hydrocarbon polyisocyanates or substituted hydrocarbon diisocyanates.
Many such organic polyisocyanates are known in the art, including p-phenylene diisocyanate, biphenyl diisocyanate, toluene diisocyanate, 3,3'-dimetllyl-4,4~-bipllenylene diisocyanate, 1,4-tetramethylene diiso-cyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexane-1,6-diisocy-anate, mcthylene bis(phenyl isocyanate), lysine diisocyanate, bis(iso-cyanatocthyl)fumarate, isophorone diisocyanate and methyl cyclohexyl diisocyanatc. Therc can also be employcd isocyanate-tcrminated adducts -of diols, such as ethylene glycol, 1,4-butylcne glycol, polyalkylene ~lycols, etc. These are formed by reacting more than one mole of a ~llisocyanatc, sucll as those mcntioned, with one mole of a diol to . ]~ -,.. . . .
- , . :: , .
. . : ' ' . . . , ~ : , lO9Z2~71 form a longer chain diisocyanate. Alternatively, the diol can be aclded alon~, with the diisocyanate.
While diisocyanates are preferred, lli~llcr polyisocyanates can ~e utilizcd as part of the organic polyisocyanate. Examples are 1,2,4-benzene triisocyanate and polymethylene polyphenyl isocyanate.
It is preferred to employ an alipllatic diisocyanate, since it has been [ound that thcse providc better color stability in the finislle(l coating. Examples include bis(isocyanatocyclohexyl)methane, 1,4-butylene diisocyanate and methylcyclohcxyl diisocyanate. The proportions of the diisocyanate and the polyhydric material are chosen so as to provide a hydroxyl-containing product. This can be accomplished by utili~ing a less than stoichiometric amount of polyisocyanate, i.e., less than one isocyanate group per hydroxyl group in the polyhydric material. Iligher (c.g., stoicl-iomctric or excess) isocyanate levels can be present if the reaction is tenninated at the desired stage, as by addition of a compound which reacts witil the residual isocyanate groups, water, alcohols and amines are examples of such compounds.
In one especially desirable embodilllent, a polyfunctional alcohol is used to terminate the reaction at the desired stage (determined by the viscosity), thereby also contributing residual hydroxyl groups.
Particularly desirable for such purposes are aminoalcohols, such as ethanolamine, diethanolamine and the like, since the amino groups preferentially react with the isocyanate groups present. Polyols, such as ethylcne glycol, trimetllylolpropane and hydroxyl-terminated poly-esters, can also be employed in this manner.
k'llile tlle ratios of the components of tlle polyhydric material the polyisocyanate and any terminating or blocking agent can be varied, lt w~ll be noted by those skilled in the art tllat the amounts should lO9Z271 be chosen so as to avoid gellation and to produce an ungelled, ure~hane reaction product colltaining hydroxyl groups. The hydroxyl value of t:llc uretllalle reaction product should be at lcast 10 and preferably 20 ~o 200.
The urethane reaction product as described above, can optionally be mi~ed witll a curing agent, along with tlle gelled polymeric micro-particles, to provide the coating composition. Other additive materials sucll as polymeric polyols of low glass transition temperature (which can be aclded before, durillg or after the reaction to form the urethane reaction product) can also be employed.
The curing agent, when one is used, can be, for example, an aminoplast resin, i.e., an alùehyde condensation product of melamine, urea, benzoguanamine or a similar compound; products obtained from the reaction of forlllaldehyde with melamine, urea or benzoguanamine are most common and are preferred herein. The aminoplast resins utilized -contain methylol or similar alkylol groups, and in most instances at least 3 portion of these alkylol groups are etherified by a reaction with an alcollol, such as methanol, butanol, 2-ethylhexanol, or the ``
like.
Other curing agents include phenolic resins formed by the condensation of an aldehyde and a phenol. A common phenolic resin is phenol~ormaldehyde resin.
Any blocked or masked organic polyisocyanate may also be used as the curing agent herein. The conventional organic polyiso-cyanates, as described above, which are blocked with a volatile alcohol, gamma-cal)rolactam, ketoximes or the like, so that tlley will be unblocked at temperatures above 100C. may be used. ~lasked poly-l~ocyan.~te.~, as is known in the art, are not derlved from isocyanates, .
,~
lO9~Z71 but do producc isocyclnate groups upon heating at elevatcd temperatures.
Examples of uscrul masked polyisocyanates ;ncllJde + _ _ +
diaminimi<les [(c-g-, (C1l3)3-N-N-~-(C~l2)4-C-N-N-(C1l3 _3], adiponitrile dicarbonate, and the like.
The curing agent may comprise up to about 60 percent by weight of the coating composition and in many cases prcferably comprises from about 4 to about 50 percent by weight of the coating composition.
Tl~c polyuretllane coating compositions arc prepare(l by blen~ g the crosslinked acrylic polymer microparticles to solutions or dispersions of the above-described urethane reaction products. The solvents employed in forming such solutions and dispersions are well known and may be any of thos~ conventionally employed in the polyurethane coatings art.
~ccordingly, any solvellt or solvcnt mixture in which tlle urethane reaction product and aminoplast resin are compatible and soluble and/or dispcrsible to the desired extent may be utili~ed. When water is desired to be utiliæed as the solvent medium, it is often preferable to include in the urethane reaction product salt groups which impart the desired degree of solubility or dispersibility in water.
In most cases, the overall polyurethane coating compositioll may contain ~rom about 30 percent to about 90 percent by weigllt of tllc urethane rcaction product, from about 0 percent to about 50 percent by weight of curing agent, and from about 2 percent to abouL 50 pcrcent by weight, preferably 2 to 20 percent by weight of the crosslinked acrylic polymer microparticles. Where it is desired to inclllde a polymeric polyol, from about 2 to about 20 percent by weight may be employed.
~s will be understoocl, when a polymeric polyol is included in the compositioll thc amount of urethane reaction product an(l curing asent will be reduccd accordingly, gcncrally on a 1:1 basis.
' ~1 , , ' ., : ' . , . . : ~; ~
~`
~09Z271 Polyester coating compositions having improved application cllaractcristics and other desirable properLies can be obtailled by blending the crosslinked acrylic polymer microparticles with an oil-modified or oil-free polyester resin, an aminoplast resin and if desired, other adcditives.
The term "oil-modified polyester" as used throughout this specification re~ers to resins produced by reacting a polyfunctional alcohol, i.e., a polyol, a polyfunctional acid (or acid anhydride) and an oil or oil fatty acid. These resins are variously referred to in the art as oil-modified polyesters or oil-modified alkyds.
A wide variety of such oil-modifiecl polyesters may be employed in forming the coating compositions. Thus, oil-modified polyester resins hnving molecular weights ranging from about 1,000 to about 10,000 may be utilized in tlle compositions of this invention.
Polyols whicll may be utili~ed in preparing the oil-modified polyester resins are preferably polyols having from 3 to 10 hydroxyl groups or diols or a mixture of a polyol and a diol.
Typical polyols having 3 or more hydroxyl groups which may be employed include trimethylol propane, trimethylol ethane, pentaery-tllritol, clipentaerythritol, glycerin, sorbitol, mannitol, hexanetriol and the like. A wicle variety of diols may be employed. Typical of the many diols which may be employed are alkylene glycols, such as ethylene glycol, propyléne glycol, butylene glycol, hexylene glycol and neopentyl glycol and other glycols such as hydrogenated Bisphenol A, cyclohexallc climethanol, caprolactone and ethylene glycol, hydroxy-alkylated bi~phellols, polyether glycols, for example, ~oly(oxytetrn-methylene)glycol ancd the like.
Tlle oil modified polyester resin will also contain a poly-fu!lctionnl acid constituellt, preferably an aromatic dicarboxylic acicd ~. .
.. . .
, , ., : ~:: .
lO~Z271 such as phthalic acid, isophthalic acid, terephthalic acid, tetrahydro-plltll;llic acid, hexallydropllthalic acid, and ~he like, or a saturated alipllatic dicarboxylic acid 9uch as succinic, glutaric, adipic, pimelic, suberic, azelaic, brassic, dodecalldoic and the like. The oil-modified polyester resin nnay also advantageously contain a minor amount of a monobasic acid constituent such as ben~oic acid, a substituted benzoic acicl or a similar monobasic aromatic acid. In addition, there may also be employed higller polycarboxylic acids such as trimellitic acid and tricarballylic acid (where acids are referred to above, it is understood that the anllydrides of those acids which form anhydrides can be used ln place of the acid). It is preferred that the oil-modiied polyester contain an aliphatic dicarboxylic acid as at least part of the acid component.
The oil employed in preparing the oil-modified polyester can be a non-drying saturated oil such as coconut oil, cottonseed oil, peanut oil,.olive oil and the like, or a drying or semi-drying oil, such as linseed oil, tall oil, soya oil, safflower oil, perilla oil, tung oil, oiticica oil, poppyseed oil, sunflower oil, dehydrated castor oil, herring oil, menhadan oil, sardine oil and the like. The above oils can be used per se or in the form of an oil fatty acid. - -The oil-modified polyester resin is produced by methods well known in the polyester resin art employins conventional techniques and proce(lures. Thus, for example, the oil-modified polyester can readily be prepared by the simple interaction of a mixture of a poly~unctioll.ll alcohol (i.e., po~yol or diol or mixture thereof), a polyfllnctional acid (or acid anllydride) and all oil or oil fatty acid.
Where the oil per se is employed, it becomes necessary as is well known in the art, ~o first convert the oil to a mono- or diglyceride by - ~3 -~09ZZ~71 alcoholysis with glycerol before adding the acid or acid anhydride and esteriEyin~.
As will be recogni~ed, tlle type and amounts of the various components wl~ich make up the oil-modified polyester resin can be varied widely, dcpending upon the physical characteristics desired in the resin. Tllus, the oil-modified polyester can be prepared in such a manllcr th~t it cxhil~its both carboxyl and hydroxy] runctionality or substantially only carboxyl functionality or essentially no functionality at all. Tlle term "functionality" as used herein refers to the number of reactive hydroxyl and carboxyl groups per molecule, with anhydride groups being considered as equivalent to two carboxyl groups. It will be noted that certain compounds contain both hydroxyl and carboxyl groups, e.g., 6-hydroxyllexanQic acid, 8-hydroxyoctanoic acid, tartaric acid, etc.
The prefcrred oil-modified polyester resins employed in these compositions are those having substantial hydroxyl functionality so that crosslinking with aminoplast resins may be readily accomplished.
As is well known in the art, hydroxyl functional polyester resins may be readily prepared by reacting an excess of the polyfunctional alcohol constituent with the polyfunctional acld constituent. The preferred oil-modified polyester resins employed in these compositions have hydroxyl values ranging from about 10 to about 200, more preferably from 40 to 120 and acid values ranging from about 0.1 to about 50, more preferably from 2 to 20.
As will be evident, it may in certain cases be desirable to forM salt groups in the above-clescribed oi]-modified polyesters for purpo.;cs ol~ water dispersibility. In that evcnt, it may be desirable ~
to ir~cl~lde a somewhat higher proportion of acid constituent in the ~ ~ I
polycster.
- 2~l -lO9ZZ7~
As indicated, the resin component of the compositions of this invention may alternatively be an oil-free polyester resin. A
~;de variety oE sucll oil-free polyester resins may be utilized in the compositions of the present invention. 'rhus, virtually any oil-free polyester resin prepared by the polyesterification of organic poly- -carboxylic acids or anhydrides thereof with organic polyols utilized heretoEore in the coatings industry may be utilized in the compositions of the invention. The preferred oil-free polyester resins are those having molecular ~eigllts ranging from 1,000 to 10,000.
The oil-free polyester produced can be prepared from those polyols utilized in the preparation of eonventional polyesters. Such polyols ineluLle ethylene glycol, propylene glycol, butylene glycol, cliethylene glycol, dipropylene glycol, triethylene glycol, neopentyl glyeol, trimethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentaneLliol, trimethylolethane, trimethylolpropane, tetralDethylene glycol, 2,3-dihydroxybutane, 1,4-dihydroxybutane, 1,4-dihydroxy-2-ethyl b-ltane, 1,6-dihytlroxyllexane, 1,3-dihydroxyoctane, 2,10-dihydroxy-deeane, 1,4-dihydroxycyclollexane, 2,2-diethylpropanediol-1,3, 2,2-diethylbutanediol-1,3, 4,5-dihydroxynonane, pentamethylene glycol, hepcameLIIylene glycol, decamethylene glyeol, butene-2-diol-1,4, 2,7-dihydroxy-ll-llexane-4, 2-ethylhexanediol-1,3, glycerol, 1,2,6-hexanetriol, pentaerythritol, sorbitol, mannitol, methyl glycoside, 2,2-bis(hydroxy-eChy]phellyl)propane, 2,2-bis(betahydroxypropoxypllenyl)propane, 2-hyLlroxyetllylhydroxyacetate, l,l-bis(hydroxymethyl)nitroethane, and Lhe like. ~dditionally, polyether polyols may be utilized, such as for example, poly(oxyethylelle)-glycol, poly(oxytetramethylene)glycol, poly(oxypentaneLIIylene)glycol and the like.
Particularly useful polyols include diols and triols. Gen-erally, Llle diol coml)ollellt includes glycols oE the Eormula II()(CII2~ Oll wlIerein n equals 2 to 10, glycols of the formulas IIO(CI-I2C1~20)nf~ and IIO[CII(CII3)CII20] II in whicIl n equals 1 to 10, such as ethylene glycol, diethylene glycol, and the like, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 3-methyl-1~5-peIltanediol~ 1,6-hexanediol, N-metIIyl an(I N-ethyl dietIIanolamines. Others-include 4,4'-methylenebis-cyclohexanol, 4,4'-isopropylidene-biscycloIlexanol and various xylene-diols, hydroxymetIlylphenyletIlyl alcohols, hydroxymethylpIlenylpropanols, phetlylenedietIIano]s, phenylenedipropanols, and heterocyclic diols such as 1,4-piperazine dietllanol and tlle like. Some of the preferred diols include 2-methyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,6- --hexanediol and 2,2-dimethyl-3-hydroxypropyl, 2,2-dimethyl-3-IIydroxy-propionaLe and the ]ike. The preferred triols (trifunctional polyols) are trimethylolpropane; trimetIIylolethane, 1,2,3-propanetriol, 1,2,4-butaIletriol; 1,2,6-hexaIletriol~ aIld the like.
A wide variety of polycarboxylie acids ean be reaeted with the above-deseribed polyols to form the oil-free polyester resins.
Virtually any of the polycarboxylic aeids eonventionally employed in oil-free polyester resins may be employed. Thus, aeids such as maleic, fumaric, itaeonie, propionic, citraconic, isobutyric, trans-crotonic, mesaeonie, aeetylene dicarboxylic, aconitric, alpha-methyl itaconic, -alpha, alpha dimetIlyl itaconic, oxalic, malonic, succinic, adipic, glutaric, brassic, dodecandoic, sebacic, 2-methylsuccinic, pimelic, 2,3-dimethyl succinic, suberic, hexyl SUCCilliC, azelaic, 3,3-diethyl ~lutaric, 3,3-dimethyl glutaric, 2,2-dimethyl glutaric, 2,2-dimethyl ~
sueeinie, phthalic, isophtIIalic, terephthalic, tetrahydrophthalic, -- -hexaI)ydrophthalie, trimellitic, tricarballylic, and the like may be utlli~ed. AnIIydrides of tllese acids, where they cxist, can be employed and are ~ncompassed by the term "polycarboxylic acid".
_ lOgZZ71 The preferred polycarboxylic acids whicil can be utilized in preparing the oil-free polyester resin component of these compositions are LhC aromatic dicarboxylic acids such as plltllaliC, iSOpllthaliC, terephtilalic, tetrahydrophtllalic, hexahydrophtllalic and the like, or the saturated aliphatic dicarbo~ylic acids such as succinic, glutaric, adipic, pimelic, suberic, a~elaic, brassic, dodecandoic, and the like.
As in the case of tlle oil-modified polyesters, the oil-free polycster rcsins employed in the coating compositions are prcferably those having hydro~yl functionality. Thus, the oil-free polyester resin may have hydroxyl values ranging from about 10 to about 200, and acid values ranging from about 0.1 to about 50.
~ s indicated above, tlle improved polycster coating compo-sitions are prepared by the addition of aminoplast resins (described above) crosslinking agents and gelled polymeric microparticles to solutions or dispersions of the above described oil-modified or oil-frce polyester resins.
Tlle aminoplast crosslinking agent may comprise up to about 60 percent by weight oE thc polyester coating composition and, in many cDses, preferably comprises from about 4 to about 50 percent by weight of the coating composition.
In most cases, the overall composition may contain from about 30 percent to about 90 percent by weight of the oil-modified or oil-free polyester resin, from about 4 percent to about 60 percent by weip,ht of the aminoplast crosslinking agent, and from about 2 percent to about 50 pcrccnt by weigllt, preferably 2 to 20 percent by weight of -thc gcll(:d polylllcric microparticles.
Thc polyurethanc and polyester coating compositions described above m~y Dlso contain otllcr ingrcdients SUCII as catalysts, plastici~ers, .:
,' ' lOg2~71 fillers, pigments and the like. This invention is particularly useful in the deposition of films containing metallic flake pigments such as aluminum, nickel, stainless steel, or tl~e like, as the pattern control of the resulting film is excellent.
The compositions are quite useful as coatings on substrates.
The compositions are applied to the substrate and baked at 150E. to 350F. for about 5 to about 60 minutes to cure tl~e coating on the substr~te. The coatings may be applied by any conventional means such as spray coating, dip coating, roll coating, and tlle likc. The pre-errecl method is spray coating as the compositions containing cross-linking polymeric microparticles can be applied with good dcposition, efficiency and rapid film build.
Any substrate such as paper, metal, wood, paperboard, plastic, foam, extrudcd rubber, and the like may be coated with these compositions.
The fo]lowing examples are submitted for the purpose of furtl~er illustrating the nature of the present invention and should not be interpreted as a limitation on the scope thereof. All parts and percentages in the examples as well as throughout tlle specification are by weight unless otherwise indicated.
EXA~LE 1 To a 5-liter flask equipped with an up and over condenser, agitator, thermometer, and heating mantle was charged 1900 grams of Napoleum*30 (a medium boiling naphtha from Kerr-McGee Company) 950 grams of hexane, and 950 grams of heptane. The mixture was heated to reflux (about 85C.) and then 200 grams of methyl methacrylate;
34 grams of a dispersion stabilizer comprising a 50.3 percent solids ;~
solution of 45.4 percent methyl metllacrylate, 4.2 percent glycidyl , * Trade Mark ~A
, . . . , , ,, . . . , . , . ~, , . . , . . ; .. . _ . .
.. . . , , .. " . . . . .. -, .. ,, .`.. , . - . - -~)9ZZ71 methacrylatc, 0.9 percent methacrylic acid, and 49 5 p~rcent of a reaction product of 8902 percent poly-12-hydroxystearic acid and 10.8 percent glycidyl methacrylate in a solvent solution comprising 52 1 percellt butyl acetate, 40.0 percent V~l&P naplltha, and 7 9 percent toluene, and 14.3 grams of azobisisobutyronitrile were added. After this addition was complete, reflux was continued for about 20 minutes and tllen over a 3-hour period was added 4060 grams methyl methacrylate, 226 grams of gamma-metl~acryloxypropyltrimetlloxysilane, 595 grams of the above dispersion stabili~er, 34.0 grams of methacrylic acid, 34.0 grams of 2-hydroxyethyl ethylenimine, 18.0 grams of azobisisobutyronitrile and 18 grams of p-octyl mercaptan. After this addition, reflux was continued for another 1.5 hours alld tlle mixture was then cooled and filtered.
The resultant polymeric dispersion consisting essentially of crosslinked polymer particles (i.e., microgel particles) had a total solids content determined at 150C. of 54.5 percent by weight.
EXAMPL~ 2 To a 5-liter flask equipped witll an up and over condenser, agitator, thermometer and heating mantle were charged 1250 grams of heptane, 540 grams of Isopar*U (a mixed aliphatic hydrocarbon having an initial boiling point of 350F. and a dry point of 371F.with 90 percent distilling between 353-357F., available from llumble Oil and Refining Company), 50 grams of methyl methacrylate, 10 grams of tlle ``
dispersion stabili~er of Example l and 4 grams Or a~obisisobutyrollitrile.
The mixture was heated to reflux (about 103C.) and held for about 30 ninutes. Thell ovcr a pcriod of about 3 hours wcre added 1288 grams of * Trade Mark ~ .
, -metl-yl methacrylatc, 70 grams o glycidyl metllacrylatc, 42 grams of methacrylic acid, 4.2 grams of Armeer~kDM(,D (dimetllyl cocoamine, availal)le from ~rmour Chemical Company), 200 grams of the dispersion stabilizer of l~xample 1, 14 grams of octyl mercal)tall and 5.6 grams of azobisisobutyronitrile. ~fter this addition was completed, reflux was continued ror an additional 30 minutes and then an additional 2.8 grams of azobisisobutyronitrile were added. Reflux was then continued for another one hour and the mixture was then cooled and i~iltered.
The resultant polymeric dispersion consisting essentially of crosslinked polymer particles (i.e. "nicrogel particles) had a total solids content determined at 150t:. of 44.9 percent by weight.
The following Examples illustrate coating compositions pre-parecl by blendillg the gelled polymeric microparl:icles ~itll polyester and polyurethane resins and other additives.
This example illustrates the preparation of gelled polymeric microparticles for use in polyurethane coating compositions.
To a 5-liter flask equipped with an up and over condenser, agitator, tllermometer and heating mantle was cllarged 1900 grams of Napoleum*30, 950 grams of hexane, and 950 grams of heptane. The mixture was l~eated to reflux (about 85C.) and then 200 grams of - methyl methacrylate; 34 grams of a dispersion stabilizer comprising a 50.3 percent solids solution of 45.4 percent methyl methacrylate,
,. : ,. ' ,. . : :
` ' ' .: : `' .` :
~9ZZ~l Organoalkoxysilane monomers wl-ich are employed in the practice of this invention are the acrylatoalkoxysilanes, mcthacrylatoalkoxysi]anes and the vinylalkoxysilanes. Illustrative of sucll compounds are acryloxypropyltrimethoxysilalle, gamma-mctil-acryloxypropyll::rimetlloxysilane, gamma-methacryloxypropyltriethoxysilane, gamma-mctllacryloxypropyl-tris(2-methoxycthoxy)silane, vinyltrimethoxy-silane, vinyltrietlloxysilane, vinyl-tris(2-mcthoxyethoxy)silane and thc like. Of thcse organoalkoxysilanes, gamma-methacryloxypropyltri-metl~oxysilane is especially preferred.
The proportion of such crosslinking monomers employed in the proccss of ~he invention may range from 0.5 perccnt Lo 15 perccnt by weight.
The cthylenically-unsaturated monomer, acid monomer and cross-linking monomer are polymerized in a dispersing liquid whicll solubilizes the monomers but in whicll the resulting polymers are cssentially not soluble and form dispersed polymer particles. The non-solvent is a hydrocarbon medium consisting essentially of liquid ali- ;
phatic hydrocarbons. A pure aliphatic hydrocarboll or a mixture of two or more may be employed. To the extent that any particular polymer produced is mostly insoluble in the hydrocarbon mcdium rcsulting, the essentially aliphatic hydrocarbon may be modified by the incorporation of other solvcllt materials such as aromatic or naphthenic hydrocarbons, and in ccrtain instances the amount of such non-aliphatic component may atLain as high as 49 percent by weight of the cntire liquid medium.
owever, the liquid medium preferably consists essenLially of aliphatic hydrocarbons and, in general, the compositions of the present invention contain less than ~5 perccnt by wcight bascd on the weight of the liquid medium of an aromatic hydrocarbon an~ often none at all at this stage.
~;
_,, . , .. _ . .... . .. . , . _ _ .
lO9ZZ~l It is essential that the hydrocarbon be of liquid character, but it may bave a wide boiling range from a minimum of about 30C. (in wl~icll case higll pressures may be necded in the polymerization) to a maxilllu~ icll may be as higll as 300C. Ior most purposes, the boiling point should be Lrom about 50C. Up to about 235C.
Examples of non-solvents useful herein are pentane, hexane, heptane, ocLanc, mixtures of thc same, and the lilie.
Ordinarily, the polymerizable composition of monomcrs and non-solvent should contain from about 30 to about 80 percent by weight o~ the non-solvcnt. It is undcrstood, however, that the monomeric solution need contain only that amount of non-solvent necessary to solubilize the monomers and maintain the resulting polymers in a dis- -persed state aftcr polymerization.
The monomers arc polymerized in the presence of a dispersion stabilizer. The dispersion stabilizer employed in producing the micro-particles of the invention is a compound, usually polymeric, which contains at least two segments of which one segment is solvated by the dispcrsing liquid and a second segment is of different polarity than the first segment and is relatively insoluble (compared to the first segment) in the dispersing liquid. Although such compounds have been used in the past to prepare dispersions of polymer, in those installces it has been considered necessary tllat the polymer produced be ungelled, film-forming and soluble in certain solvents.
~ ncludcd among such dispersion stabilizers are polyacrylates and polymetllacrylates, such as poly(lauryl)methacrylate and poly(2-ethyl-hexyl acrylate); diene polymers and copolymers such as polybutadiene and degraded rubbers; aminoplast resins, particularly higllly naphtlla-tolerant compounds such as mclamine-formaldehyde resins etherified ` 109ZZ71 with hi~ller alcohols (e.g., alcohols having 4 to 12 carbon atoms), for example, butanol, hexanol, 2-ethylllexallol, etc., and other aminoplasts of similar characteristics such as certain resins based on urea, benzo-guallamille, and the like; and various copolymers dcsigned to have the desired char.lcteristics, for example, polyethylene vinyl acetate co-polymers .
Illc presently prererred dispcrsion stabilizcrs used in thisinventioll are graft copolymers comprising two types of polymer components of wllich one segment is solvated by the aliphatic hydrocarbon solvent and is usually not associated with polymerized particles of the poly- --merizable ethylenically-unsaturated monomer and the second type is an anchor polymer of different polarity from the first type and being relativcly non-solvatable by tlle aliphatic hydrocarbon solvent and capable o~ anchoring with the polymerized particles of the ethylenically unsat~lrated monomer, said anchor polymer containing pendant eroups - -capal-le of copolymerizing with etllylenically-unsaturated monomers.
The preferred dispersion stabilizers are comprised of two segments. The first segment (A) comprises the reaction product of (1) a long-chain hydrocarbon molecule which is solvatable by the dispersing liq~id and contains a terminal reactive group and (2) an ethylenically-unsaturated compound wllicll is copolymeri~able with the ethylenically unsaturated monomer to be polymerized and which contains a functional ~roup capable of reacting with the terminal reactive group of the long-chain hydrocarbon molecule (1).
Generally, the solvatable segment (~) is a monofunctional polymerlc material of molecular weight of about 300 to about 3,000.
Thcse polymcrs may be madc, for example, by condensation reaction producin~ ~ polyester or polyether. The most conveniellt monomers to . ' .
~(~9ZZ71 use are hydroxy acids or lactones wllich form hydroxy acid polymers.
lor example, a hydroxy fa~ty acid sucll as 12-llydroxystearic acid may be polymerized to form a non-polar component solvatable by such non-polar organic liquids as aliphatic and aromatic hydrocarbons. The polyhydroxy stearic acid may then be reacted with a compound which is eopolymerizable witl- the acrylic monomer to be polymerized, such as glycidyl acrylate or glycidyl methacrylate. The glycidyl group would react witll the carboxyl groups of tlle polyllydroxy stearic acid and the polymer segment (A) would be formed.
Somewhat more complex, but still useful, polyesters may be made by reacting diacids with diols. For example, 1,12-dodecanediol may be reaeted with sebaciC acid or its diacid chloride to form a component solvatable by aliphatic hydrocarbons.
The preferred polymeric segment (A) of tl-e dispersion stabilizer is formed by reacting poly-(12-hydroxystearic acid) with glycidyl meth-....
acrylate.
Tlle second polymeric segment (B) of the dispersion stabilizeris of polarity different from the first segment (A) and, as such, is relatively non-solvated by the dispersing liquid and is associated with or eapable of anchoring onto tlle acrylic polymeric particles formed by the polymerization and contains a pendant group which is copolymerizable with the acrylic monomer. This anchor segment (B) provides around the polymerized particles a layer of the stabilizer. The solvated polymer ~egmenC (A) which extends outwardly from the surface of the partieles provi(les a solvated barrier wl-ieh sterieally stabilizes the polymerized particles in dispersed form.
rhe anchor segment (B) may eomprise copolymers of (1) compounds whleh .~re rea~lily associated Witll the acrylic mononler to be polymerized ' _ Ll _ .. .. . .
such as acrylic or methacrylic esters, such as methyl acrylate, methyl metllacrylatc, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl metllacrylate, 2-ethylllexyl acrylate, octyl methacrylate, and the like, wiLh (2) compounds ~hich contain groups copolymerizable with the acrylic monomer to be polymerized and which contain groups which are reactive witll the polymeric segment (A), such as glycidyl-containing acrylates and mctl-acrylatcs, such as glycidyl acrylate and glycidyl methacrylate.
These copolymers are further reacted with polymerizable ethylenically-unsnturated acids, such as acrylic acid, methacrylic acid, 3-butenoic acid, crotonic acid, itaconic acid, and others mentioned previously which contain pendant groups which are copolymerizable with the acrylic monomer.
The preferred polymeric segtnent (~) is a terpolymer of methyl methacrylate, glycidyl methacrylate, and methacrylic acid.
The segments (~) and (B) are usually combined entities, the segment (A) being attached to the backbone of the graft copolymer and the segment (~) being carried in or on the backbone.
The mollomer solution containing the stabilizer preferably con-tains from about 1 to about 25 percent by weight of the stabilizer.
; Tlle polymerization may be carried out in a conventional manner, utilizing heat and/or catalysts and varying solvents and techniques.
Cenerally, a free radical catalyst such as cumene hydroperoxide, benzoyl peroxide or similar peroxygen compound, or an azo compound such as azo-bisisobutyronitrile is employed. ~ :
The resultant non-aqueous acrylic dispersion CollSiStS ess-entially of microgel particles (i.e., crosslinked polymer particles) dispersed therein. These particles have particle sizes ranging from 0,1 to 10 microns. Depending upon the original concentration of ,: . . ' '. .. ` ' ' ' ~ `: ' ' :
~" 109ZZ71 monomer solids, non-aqueous dispersions consisting essentially of the microgel particles can be produced by the process at relatively hi~h conccntrations. The term "relatively high concentration" as employed llerein refers to tl~e solids level of the non-aqueous dispersion. Thus, the proccss of this invention permits the production of non-aqueous dispcrsions of microgel particles having solids contents of from 20 to 60 percent by weight or even higher.
As mentioned above, the gelled polymeric micropartlcles pre-pared by the proccss, can be blended with various resins such as poly-urethanes, polyesters and the like to produce coating compositions having improved application characteristics and other desirable properties.
Thus, by blending these gelled polymeric microparticles in appropriate quantities with resins of the above type, coating compositions can be obtained whicll upon application exhibit improved f ilm build, metallic pattern control and flow control. Moreover, these improved character-istics can be obtained without adversely affecting the gloss of films formed from the resultallt coating compositions. A particularly sig-nificant improvement obtained when these gelled polymeric microparticles are included in a coating composition is as indicated in the area of film build, particularly the film build of compositions utilized as topcoat materials in the automotive industry. Heretofore, most commercial topcoat compositions for use in the automotive industry -when spray applied often required at least three spray coats to obtain films havlng the desired thickness. By including an appropriate quantity of the ~elled polymeric microparticIes produced in tllis invention in --sucll topcoaL compositions, the same thickness can be obtained in two spray coats.
' ' ''' :'' -, lO9ZZ71 Polyurethane coating compositions having the improved appli-cation characteristics and other desirable properties can be obtained by blending the crosslinked acrylic polymer microparticles with an iso-cyanate modified resin containing hydroxyl groups, formed by reacting a polyhydric material with an organic polyisocyanate, and, if desired, curing agents and other additives.
The polyhydric material preferably contains a polymeric polyol sucll as a polyether polyol, a polyester polyol, or an acrylic polyol. The polymcric polyol sh~uld be predominalltly linear (that is, absence of crosslinks) to avoid gelling of the resultant polymeric product and should have a molecular weight of between 500 and 5000.
As exampl:es of polyether polyols, any suitable polyalkylene ether polyol may be used including those which have the following strucLural formula:
m where R is hydrogen or lower alkyl and n is typically from 2 to 6 and m is from 2 to 100 or even higher. Included are poly(oxytetramethylene) glycols, poly(oxyethylene)glycols, poly(oxytrimethylene)glycols, poly (oxypentamethylene)glycols, polypropylene glycols, etc. ~Lso useful are polyethcr polyols formed from the oxyalkylation of various polyols, for example, glycols &uch as ethylene glycol, 1,6-hexanediol and the likc, or highcr polyols, such as trimethylol propane, trimethylolethane, pentaerythritol and the like. Polyols of higller functionality which can be utilizcd as indicated can be made, for instance, by oxyalkylation of compounds a5 ~orbitoL or sucro~e.
S'- , ~ 14 -~- 1092271 Also suitable are polyby(lric po]ythioether such as, for example, tlle condensation product of thioglycol or the reaction product of a polyhydric alcohol with thioglycolic or any other suitable glycol.
Polyester polyols can also be used as a polymeric polyol component in making the polyurethane resin. Such polyester polyols --calt be prepared by the polyesterif ication of organic polycarboxylic acids or anhydrides thereof with organic polyols. Usually, the poly-cnrboxylic acids and polyols are alipllatic or aromatic dibasic acids and diols, although a minor amount, i.e., up to about 25 mole percent of polyols and polybasic acids having a functionality of 3 or more, can be used. Ilowever, the use of higher functionality polybasic acids anù polyols must be carefully controlled so as to avoid gelling in the resultant polymeric product. Diols which are usually employed in making the polyester include alkylene glycols, such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol and neo- -pentyl glycol and other glycols such as hydrogenated Bisphenol A, cyclohexane dimetllanol, caprolactone diol (for example, the reaction product of caprolactone and ethylene glycol), hydroxyalkylated bis-phenols, polyether glycols, for example, poly(oxytetrametllylene)glycol and the like. Ilowever, other diols of various types and, as indicated, --polyols of higher functionality can also be utilized, including for example, trimethylol propane, trimethylol ethane, pentaerythritol, and the likc, as well as higher molecular weight polyols such as those produceù by oxyalkylating low molecular weight polyols.
The acid component of the polyester conslsts primarily of monomeric carboxylic acids or anhydrides having 2 to 14 carbon atoms pcr m~lecllle. Tlle acld sho-lld have an average [ullctionlllity of at lOgZZ71 least about 1.9; the acid component in most instances contains at least 75 mole percent of dicarboY.ylic acids or anhydrides Tlle functionality of the acid component is based upon considerations similar to those discussed above in connection with the alcohol component, the to~al functionality of the system being kept in mind.
Among the acids whicll are useful are phthalic acid, iso-phtllalic acid, terephthalic acid, tetrahydrophthalic acid, hexa-hydrophtllcllic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, glutaric acid, chlorendic acid, tetrachlorophthalic acid, and otller dicarboxylic acids of varying types. The polyester may include --minor amounts of monobasic acid, SUCll as benzoic acid, and there may also be employed l~igller polycarboxylic acids such as trimellitic acid and tricarballylic acid (where acids are referred to above, it is understood that the anhydrides of those acids whicll form anhydrides can be used in place of the acid3. It is preferred that the polyester include an aliphatic dicarboxylic acid as at least part of the acid component.
The polyester polyols useful herein also include polyester amide polyols, and polyhydric compounds having polyester structures but not fonned from the reaction of an alcohol and an acid. Examples of this latter type include the so-called lactone polyesters, such as polycaprolactone polyols, as described in U.S. Patent 3,169,945 to llostettler et al.
Besides polyether and polyester polyols, useful polyoIs in-clude hy~roxyl-containing interpolymers of ethylenically unsaturated --monomers. I'xamples o ~uch interpolymers are the so-called acrylic polyols, which include interpolymers of a hydroxyalkyl ester of an ethylenlcally unsaturated carboxylic acid and one or more copolymeri~able ethylenically unsaturated compounds.
- l6 -lO9Z271 The preferred in~crpolymers are those containing hydroxy groups dcrivcd fro~ 0noacrylates or mctl~acry]atcs of a diol such as llydroxyalkyl acrylates and metllacrylates. Ixamples include acrylic acid and methacrylic acid esters of ethylene glycol and 1,2-propylene glycol such as hydroxyetllyl acrylate and methacrylate and hydroxy-propyl methacrylate as well as polyethylene glycol monoacrylate and polycal)rolaccone diol or polyol monoacrylate. ~Iydroxybutyl acrylate, llydroxyoc~yl methacrylate, and the like are further examples of the llydroxy.lll;yl estcrs of tlle interpolymer. ~lso useful are the hydroxy-containing esters of such unsaturated acids as maleic acid, fumaric acid, itaconic acid, and tlle like. Tlle hydroxyalkyl ester is inter-polymerized with any ethylenically unsaturated compound copolymerizable witll the ester, the polymerization taking place througll tlle ethylenlcally unsaturated linkagcs; acrylic monomers and vinyl aromatic hydrocarbon monomers are often utilized. Functional monomers, such as acrylamide, N-alkoxyalkyl acrylamides and masked or blocked ethylenically unsaturated isocyanates may also be used.
One particularly preferred class of acrylic polyols comprises in`terpolymers of hydroxyethyl acrylate or metllacrylate, one or more `~
lower alkyl acrylates and, if desired, an unsaturated nitrile and an N-alkoxymethyl acrylamide.
Besides polymeric polyols, low molecular weight polyols, that is tllosc having molecular weights up to 250, can be employed as part or all of the polyhydric material. The low molecular weight polyols incllldc diols, triols an(l higllcr alcohols. Sucll matcrials include alipllatic polyols particularly alkylene polyols containing from about 2 to lS carbon atoms. Examples include ethylelle glycol, 1,2-propancdiol, 1,4-butanedlol, 1,6-1lexanediol, 2-methyl-1,3 pentancdiol; cycloaliphatic .
, , .-: : , , , i , ,, , , :
polyols such as 1,2-cyclohexanediol, 1,2-bis(hydroxyrnethyl)cyclohexane and cyclohexane dimcthanol. Examples of triols and higher alcohols include trimethylol propane, trimethylol ethane, glycerol and pen-taerythritol. ~lso useful are polyols containing ether linkages such as diethylene glycol, and triethylene glycol.
To producc optimum coatings, the overall functionality per unit weigllt of the reaction system should be controlled. Preferably, there should not be present more than about one gram-mole of acids and/or alcohols having a functionality of 3 or more, per 500 grams of tlle total weight of these compounds. By "functionality" is meant the number of reactive hydroxyl and carboxyl groups per molecule, with anhydride groups being considered as equivalent to two carboxyl groups.
It can be noted that certain compounds contain both hydroxyl and car-boxyl groups; examples are 6-hydroxyhexanoic acid, 8-hydroxyoctanoic acid, tartaric acid, etc.
The organic polyisocyanate which is reacted with the poly-hydric material as described is e.sscntially any polyisocyanate, e.g., hydrocarbon polyisocyanates or substituted hydrocarbon diisocyanates.
Many such organic polyisocyanates are known in the art, including p-phenylene diisocyanate, biphenyl diisocyanate, toluene diisocyanate, 3,3'-dimetllyl-4,4~-bipllenylene diisocyanate, 1,4-tetramethylene diiso-cyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexane-1,6-diisocy-anate, mcthylene bis(phenyl isocyanate), lysine diisocyanate, bis(iso-cyanatocthyl)fumarate, isophorone diisocyanate and methyl cyclohexyl diisocyanatc. Therc can also be employcd isocyanate-tcrminated adducts -of diols, such as ethylene glycol, 1,4-butylcne glycol, polyalkylene ~lycols, etc. These are formed by reacting more than one mole of a ~llisocyanatc, sucll as those mcntioned, with one mole of a diol to . ]~ -,.. . . .
- , . :: , .
. . : ' ' . . . , ~ : , lO9Z2~71 form a longer chain diisocyanate. Alternatively, the diol can be aclded alon~, with the diisocyanate.
While diisocyanates are preferred, lli~llcr polyisocyanates can ~e utilizcd as part of the organic polyisocyanate. Examples are 1,2,4-benzene triisocyanate and polymethylene polyphenyl isocyanate.
It is preferred to employ an alipllatic diisocyanate, since it has been [ound that thcse providc better color stability in the finislle(l coating. Examples include bis(isocyanatocyclohexyl)methane, 1,4-butylene diisocyanate and methylcyclohcxyl diisocyanate. The proportions of the diisocyanate and the polyhydric material are chosen so as to provide a hydroxyl-containing product. This can be accomplished by utili~ing a less than stoichiometric amount of polyisocyanate, i.e., less than one isocyanate group per hydroxyl group in the polyhydric material. Iligher (c.g., stoicl-iomctric or excess) isocyanate levels can be present if the reaction is tenninated at the desired stage, as by addition of a compound which reacts witil the residual isocyanate groups, water, alcohols and amines are examples of such compounds.
In one especially desirable embodilllent, a polyfunctional alcohol is used to terminate the reaction at the desired stage (determined by the viscosity), thereby also contributing residual hydroxyl groups.
Particularly desirable for such purposes are aminoalcohols, such as ethanolamine, diethanolamine and the like, since the amino groups preferentially react with the isocyanate groups present. Polyols, such as ethylcne glycol, trimetllylolpropane and hydroxyl-terminated poly-esters, can also be employed in this manner.
k'llile tlle ratios of the components of tlle polyhydric material the polyisocyanate and any terminating or blocking agent can be varied, lt w~ll be noted by those skilled in the art tllat the amounts should lO9Z271 be chosen so as to avoid gellation and to produce an ungelled, ure~hane reaction product colltaining hydroxyl groups. The hydroxyl value of t:llc uretllalle reaction product should be at lcast 10 and preferably 20 ~o 200.
The urethane reaction product as described above, can optionally be mi~ed witll a curing agent, along with tlle gelled polymeric micro-particles, to provide the coating composition. Other additive materials sucll as polymeric polyols of low glass transition temperature (which can be aclded before, durillg or after the reaction to form the urethane reaction product) can also be employed.
The curing agent, when one is used, can be, for example, an aminoplast resin, i.e., an alùehyde condensation product of melamine, urea, benzoguanamine or a similar compound; products obtained from the reaction of forlllaldehyde with melamine, urea or benzoguanamine are most common and are preferred herein. The aminoplast resins utilized -contain methylol or similar alkylol groups, and in most instances at least 3 portion of these alkylol groups are etherified by a reaction with an alcollol, such as methanol, butanol, 2-ethylhexanol, or the ``
like.
Other curing agents include phenolic resins formed by the condensation of an aldehyde and a phenol. A common phenolic resin is phenol~ormaldehyde resin.
Any blocked or masked organic polyisocyanate may also be used as the curing agent herein. The conventional organic polyiso-cyanates, as described above, which are blocked with a volatile alcohol, gamma-cal)rolactam, ketoximes or the like, so that tlley will be unblocked at temperatures above 100C. may be used. ~lasked poly-l~ocyan.~te.~, as is known in the art, are not derlved from isocyanates, .
,~
lO9~Z71 but do producc isocyclnate groups upon heating at elevatcd temperatures.
Examples of uscrul masked polyisocyanates ;ncllJde + _ _ +
diaminimi<les [(c-g-, (C1l3)3-N-N-~-(C~l2)4-C-N-N-(C1l3 _3], adiponitrile dicarbonate, and the like.
The curing agent may comprise up to about 60 percent by weight of the coating composition and in many cases prcferably comprises from about 4 to about 50 percent by weight of the coating composition.
Tl~c polyuretllane coating compositions arc prepare(l by blen~ g the crosslinked acrylic polymer microparticles to solutions or dispersions of the above-described urethane reaction products. The solvents employed in forming such solutions and dispersions are well known and may be any of thos~ conventionally employed in the polyurethane coatings art.
~ccordingly, any solvellt or solvcnt mixture in which tlle urethane reaction product and aminoplast resin are compatible and soluble and/or dispcrsible to the desired extent may be utili~ed. When water is desired to be utiliæed as the solvent medium, it is often preferable to include in the urethane reaction product salt groups which impart the desired degree of solubility or dispersibility in water.
In most cases, the overall polyurethane coating compositioll may contain ~rom about 30 percent to about 90 percent by weigllt of tllc urethane rcaction product, from about 0 percent to about 50 percent by weight of curing agent, and from about 2 percent to abouL 50 pcrcent by weight, preferably 2 to 20 percent by weight of the crosslinked acrylic polymer microparticles. Where it is desired to inclllde a polymeric polyol, from about 2 to about 20 percent by weight may be employed.
~s will be understoocl, when a polymeric polyol is included in the compositioll thc amount of urethane reaction product an(l curing asent will be reduccd accordingly, gcncrally on a 1:1 basis.
' ~1 , , ' ., : ' . , . . : ~; ~
~`
~09Z271 Polyester coating compositions having improved application cllaractcristics and other desirable properLies can be obtailled by blending the crosslinked acrylic polymer microparticles with an oil-modified or oil-free polyester resin, an aminoplast resin and if desired, other adcditives.
The term "oil-modified polyester" as used throughout this specification re~ers to resins produced by reacting a polyfunctional alcohol, i.e., a polyol, a polyfunctional acid (or acid anhydride) and an oil or oil fatty acid. These resins are variously referred to in the art as oil-modified polyesters or oil-modified alkyds.
A wide variety of such oil-modifiecl polyesters may be employed in forming the coating compositions. Thus, oil-modified polyester resins hnving molecular weights ranging from about 1,000 to about 10,000 may be utilized in tlle compositions of this invention.
Polyols whicll may be utili~ed in preparing the oil-modified polyester resins are preferably polyols having from 3 to 10 hydroxyl groups or diols or a mixture of a polyol and a diol.
Typical polyols having 3 or more hydroxyl groups which may be employed include trimethylol propane, trimethylol ethane, pentaery-tllritol, clipentaerythritol, glycerin, sorbitol, mannitol, hexanetriol and the like. A wicle variety of diols may be employed. Typical of the many diols which may be employed are alkylene glycols, such as ethylene glycol, propyléne glycol, butylene glycol, hexylene glycol and neopentyl glycol and other glycols such as hydrogenated Bisphenol A, cyclohexallc climethanol, caprolactone and ethylene glycol, hydroxy-alkylated bi~phellols, polyether glycols, for example, ~oly(oxytetrn-methylene)glycol ancd the like.
Tlle oil modified polyester resin will also contain a poly-fu!lctionnl acid constituellt, preferably an aromatic dicarboxylic acicd ~. .
.. . .
, , ., : ~:: .
lO~Z271 such as phthalic acid, isophthalic acid, terephthalic acid, tetrahydro-plltll;llic acid, hexallydropllthalic acid, and ~he like, or a saturated alipllatic dicarboxylic acid 9uch as succinic, glutaric, adipic, pimelic, suberic, azelaic, brassic, dodecalldoic and the like. The oil-modified polyester resin nnay also advantageously contain a minor amount of a monobasic acid constituent such as ben~oic acid, a substituted benzoic acicl or a similar monobasic aromatic acid. In addition, there may also be employed higller polycarboxylic acids such as trimellitic acid and tricarballylic acid (where acids are referred to above, it is understood that the anllydrides of those acids which form anhydrides can be used ln place of the acid). It is preferred that the oil-modiied polyester contain an aliphatic dicarboxylic acid as at least part of the acid component.
The oil employed in preparing the oil-modified polyester can be a non-drying saturated oil such as coconut oil, cottonseed oil, peanut oil,.olive oil and the like, or a drying or semi-drying oil, such as linseed oil, tall oil, soya oil, safflower oil, perilla oil, tung oil, oiticica oil, poppyseed oil, sunflower oil, dehydrated castor oil, herring oil, menhadan oil, sardine oil and the like. The above oils can be used per se or in the form of an oil fatty acid. - -The oil-modified polyester resin is produced by methods well known in the polyester resin art employins conventional techniques and proce(lures. Thus, for example, the oil-modified polyester can readily be prepared by the simple interaction of a mixture of a poly~unctioll.ll alcohol (i.e., po~yol or diol or mixture thereof), a polyfllnctional acid (or acid anllydride) and all oil or oil fatty acid.
Where the oil per se is employed, it becomes necessary as is well known in the art, ~o first convert the oil to a mono- or diglyceride by - ~3 -~09ZZ~71 alcoholysis with glycerol before adding the acid or acid anhydride and esteriEyin~.
As will be recogni~ed, tlle type and amounts of the various components wl~ich make up the oil-modified polyester resin can be varied widely, dcpending upon the physical characteristics desired in the resin. Tllus, the oil-modified polyester can be prepared in such a manllcr th~t it cxhil~its both carboxyl and hydroxy] runctionality or substantially only carboxyl functionality or essentially no functionality at all. Tlle term "functionality" as used herein refers to the number of reactive hydroxyl and carboxyl groups per molecule, with anhydride groups being considered as equivalent to two carboxyl groups. It will be noted that certain compounds contain both hydroxyl and carboxyl groups, e.g., 6-hydroxyllexanQic acid, 8-hydroxyoctanoic acid, tartaric acid, etc.
The prefcrred oil-modified polyester resins employed in these compositions are those having substantial hydroxyl functionality so that crosslinking with aminoplast resins may be readily accomplished.
As is well known in the art, hydroxyl functional polyester resins may be readily prepared by reacting an excess of the polyfunctional alcohol constituent with the polyfunctional acld constituent. The preferred oil-modified polyester resins employed in these compositions have hydroxyl values ranging from about 10 to about 200, more preferably from 40 to 120 and acid values ranging from about 0.1 to about 50, more preferably from 2 to 20.
As will be evident, it may in certain cases be desirable to forM salt groups in the above-clescribed oi]-modified polyesters for purpo.;cs ol~ water dispersibility. In that evcnt, it may be desirable ~
to ir~cl~lde a somewhat higher proportion of acid constituent in the ~ ~ I
polycster.
- 2~l -lO9ZZ7~
As indicated, the resin component of the compositions of this invention may alternatively be an oil-free polyester resin. A
~;de variety oE sucll oil-free polyester resins may be utilized in the compositions of the present invention. 'rhus, virtually any oil-free polyester resin prepared by the polyesterification of organic poly- -carboxylic acids or anhydrides thereof with organic polyols utilized heretoEore in the coatings industry may be utilized in the compositions of the invention. The preferred oil-free polyester resins are those having molecular ~eigllts ranging from 1,000 to 10,000.
The oil-free polyester produced can be prepared from those polyols utilized in the preparation of eonventional polyesters. Such polyols ineluLle ethylene glycol, propylene glycol, butylene glycol, cliethylene glycol, dipropylene glycol, triethylene glycol, neopentyl glyeol, trimethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentaneLliol, trimethylolethane, trimethylolpropane, tetralDethylene glycol, 2,3-dihydroxybutane, 1,4-dihydroxybutane, 1,4-dihydroxy-2-ethyl b-ltane, 1,6-dihytlroxyllexane, 1,3-dihydroxyoctane, 2,10-dihydroxy-deeane, 1,4-dihydroxycyclollexane, 2,2-diethylpropanediol-1,3, 2,2-diethylbutanediol-1,3, 4,5-dihydroxynonane, pentamethylene glycol, hepcameLIIylene glycol, decamethylene glyeol, butene-2-diol-1,4, 2,7-dihydroxy-ll-llexane-4, 2-ethylhexanediol-1,3, glycerol, 1,2,6-hexanetriol, pentaerythritol, sorbitol, mannitol, methyl glycoside, 2,2-bis(hydroxy-eChy]phellyl)propane, 2,2-bis(betahydroxypropoxypllenyl)propane, 2-hyLlroxyetllylhydroxyacetate, l,l-bis(hydroxymethyl)nitroethane, and Lhe like. ~dditionally, polyether polyols may be utilized, such as for example, poly(oxyethylelle)-glycol, poly(oxytetramethylene)glycol, poly(oxypentaneLIIylene)glycol and the like.
Particularly useful polyols include diols and triols. Gen-erally, Llle diol coml)ollellt includes glycols oE the Eormula II()(CII2~ Oll wlIerein n equals 2 to 10, glycols of the formulas IIO(CI-I2C1~20)nf~ and IIO[CII(CII3)CII20] II in whicIl n equals 1 to 10, such as ethylene glycol, diethylene glycol, and the like, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 3-methyl-1~5-peIltanediol~ 1,6-hexanediol, N-metIIyl an(I N-ethyl dietIIanolamines. Others-include 4,4'-methylenebis-cyclohexanol, 4,4'-isopropylidene-biscycloIlexanol and various xylene-diols, hydroxymetIlylphenyletIlyl alcohols, hydroxymethylpIlenylpropanols, phetlylenedietIIano]s, phenylenedipropanols, and heterocyclic diols such as 1,4-piperazine dietllanol and tlle like. Some of the preferred diols include 2-methyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,6- --hexanediol and 2,2-dimethyl-3-hydroxypropyl, 2,2-dimethyl-3-IIydroxy-propionaLe and the ]ike. The preferred triols (trifunctional polyols) are trimethylolpropane; trimetIIylolethane, 1,2,3-propanetriol, 1,2,4-butaIletriol; 1,2,6-hexaIletriol~ aIld the like.
A wide variety of polycarboxylie acids ean be reaeted with the above-deseribed polyols to form the oil-free polyester resins.
Virtually any of the polycarboxylic aeids eonventionally employed in oil-free polyester resins may be employed. Thus, aeids such as maleic, fumaric, itaeonie, propionic, citraconic, isobutyric, trans-crotonic, mesaeonie, aeetylene dicarboxylic, aconitric, alpha-methyl itaconic, -alpha, alpha dimetIlyl itaconic, oxalic, malonic, succinic, adipic, glutaric, brassic, dodecandoic, sebacic, 2-methylsuccinic, pimelic, 2,3-dimethyl succinic, suberic, hexyl SUCCilliC, azelaic, 3,3-diethyl ~lutaric, 3,3-dimethyl glutaric, 2,2-dimethyl glutaric, 2,2-dimethyl ~
sueeinie, phthalic, isophtIIalic, terephthalic, tetrahydrophthalic, -- -hexaI)ydrophthalie, trimellitic, tricarballylic, and the like may be utlli~ed. AnIIydrides of tllese acids, where they cxist, can be employed and are ~ncompassed by the term "polycarboxylic acid".
_ lOgZZ71 The preferred polycarboxylic acids whicil can be utilized in preparing the oil-free polyester resin component of these compositions are LhC aromatic dicarboxylic acids such as plltllaliC, iSOpllthaliC, terephtilalic, tetrahydrophtllalic, hexahydrophtllalic and the like, or the saturated aliphatic dicarbo~ylic acids such as succinic, glutaric, adipic, pimelic, suberic, a~elaic, brassic, dodecandoic, and the like.
As in the case of tlle oil-modified polyesters, the oil-free polycster rcsins employed in the coating compositions are prcferably those having hydro~yl functionality. Thus, the oil-free polyester resin may have hydroxyl values ranging from about 10 to about 200, and acid values ranging from about 0.1 to about 50.
~ s indicated above, tlle improved polycster coating compo-sitions are prepared by the addition of aminoplast resins (described above) crosslinking agents and gelled polymeric microparticles to solutions or dispersions of the above described oil-modified or oil-frce polyester resins.
Tlle aminoplast crosslinking agent may comprise up to about 60 percent by weight oE thc polyester coating composition and, in many cDses, preferably comprises from about 4 to about 50 percent by weight of the coating composition.
In most cases, the overall composition may contain from about 30 percent to about 90 percent by weight of the oil-modified or oil-free polyester resin, from about 4 percent to about 60 percent by weip,ht of the aminoplast crosslinking agent, and from about 2 percent to about 50 pcrccnt by weigllt, preferably 2 to 20 percent by weight of -thc gcll(:d polylllcric microparticles.
Thc polyurethanc and polyester coating compositions described above m~y Dlso contain otllcr ingrcdients SUCII as catalysts, plastici~ers, .:
,' ' lOg2~71 fillers, pigments and the like. This invention is particularly useful in the deposition of films containing metallic flake pigments such as aluminum, nickel, stainless steel, or tl~e like, as the pattern control of the resulting film is excellent.
The compositions are quite useful as coatings on substrates.
The compositions are applied to the substrate and baked at 150E. to 350F. for about 5 to about 60 minutes to cure tl~e coating on the substr~te. The coatings may be applied by any conventional means such as spray coating, dip coating, roll coating, and tlle likc. The pre-errecl method is spray coating as the compositions containing cross-linking polymeric microparticles can be applied with good dcposition, efficiency and rapid film build.
Any substrate such as paper, metal, wood, paperboard, plastic, foam, extrudcd rubber, and the like may be coated with these compositions.
The fo]lowing examples are submitted for the purpose of furtl~er illustrating the nature of the present invention and should not be interpreted as a limitation on the scope thereof. All parts and percentages in the examples as well as throughout tlle specification are by weight unless otherwise indicated.
EXA~LE 1 To a 5-liter flask equipped with an up and over condenser, agitator, thermometer, and heating mantle was charged 1900 grams of Napoleum*30 (a medium boiling naphtha from Kerr-McGee Company) 950 grams of hexane, and 950 grams of heptane. The mixture was heated to reflux (about 85C.) and then 200 grams of methyl methacrylate;
34 grams of a dispersion stabilizer comprising a 50.3 percent solids ;~
solution of 45.4 percent methyl metllacrylate, 4.2 percent glycidyl , * Trade Mark ~A
, . . . , , ,, . . . , . , . ~, , . . , . . ; .. . _ . .
.. . . , , .. " . . . . .. -, .. ,, .`.. , . - . - -~)9ZZ71 methacrylatc, 0.9 percent methacrylic acid, and 49 5 p~rcent of a reaction product of 8902 percent poly-12-hydroxystearic acid and 10.8 percent glycidyl methacrylate in a solvent solution comprising 52 1 percellt butyl acetate, 40.0 percent V~l&P naplltha, and 7 9 percent toluene, and 14.3 grams of azobisisobutyronitrile were added. After this addition was complete, reflux was continued for about 20 minutes and tllen over a 3-hour period was added 4060 grams methyl methacrylate, 226 grams of gamma-metl~acryloxypropyltrimetlloxysilane, 595 grams of the above dispersion stabili~er, 34.0 grams of methacrylic acid, 34.0 grams of 2-hydroxyethyl ethylenimine, 18.0 grams of azobisisobutyronitrile and 18 grams of p-octyl mercaptan. After this addition, reflux was continued for another 1.5 hours alld tlle mixture was then cooled and filtered.
The resultant polymeric dispersion consisting essentially of crosslinked polymer particles (i.e., microgel particles) had a total solids content determined at 150C. of 54.5 percent by weight.
EXAMPL~ 2 To a 5-liter flask equipped witll an up and over condenser, agitator, thermometer and heating mantle were charged 1250 grams of heptane, 540 grams of Isopar*U (a mixed aliphatic hydrocarbon having an initial boiling point of 350F. and a dry point of 371F.with 90 percent distilling between 353-357F., available from llumble Oil and Refining Company), 50 grams of methyl methacrylate, 10 grams of tlle ``
dispersion stabili~er of Example l and 4 grams Or a~obisisobutyrollitrile.
The mixture was heated to reflux (about 103C.) and held for about 30 ninutes. Thell ovcr a pcriod of about 3 hours wcre added 1288 grams of * Trade Mark ~ .
, -metl-yl methacrylatc, 70 grams o glycidyl metllacrylatc, 42 grams of methacrylic acid, 4.2 grams of Armeer~kDM(,D (dimetllyl cocoamine, availal)le from ~rmour Chemical Company), 200 grams of the dispersion stabilizer of l~xample 1, 14 grams of octyl mercal)tall and 5.6 grams of azobisisobutyronitrile. ~fter this addition was completed, reflux was continued ror an additional 30 minutes and then an additional 2.8 grams of azobisisobutyronitrile were added. Reflux was then continued for another one hour and the mixture was then cooled and i~iltered.
The resultant polymeric dispersion consisting essentially of crosslinked polymer particles (i.e. "nicrogel particles) had a total solids content determined at 150t:. of 44.9 percent by weight.
The following Examples illustrate coating compositions pre-parecl by blendillg the gelled polymeric microparl:icles ~itll polyester and polyurethane resins and other additives.
This example illustrates the preparation of gelled polymeric microparticles for use in polyurethane coating compositions.
To a 5-liter flask equipped with an up and over condenser, agitator, tllermometer and heating mantle was cllarged 1900 grams of Napoleum*30, 950 grams of hexane, and 950 grams of heptane. The mixture was l~eated to reflux (about 85C.) and then 200 grams of - methyl methacrylate; 34 grams of a dispersion stabilizer comprising a 50.3 percent solids solution of 45.4 percent methyl methacrylate,
4.2 percellt glycidyl methacrylate, 0.9 percent meLIIacrylic acid, all(l 49.5 percenl: of a reaction product of 89.2 percent poly-12-hydroxy-stear~c acicl and 1().8 percent glycidyl metllacrylate in a solvent * Trade Mark !~:
, solution comprising 52.1 pcrcent butyl acetate, 40.0 pcrcent VM&P
naphtha, and 7.9 percent toluene, and 14.3 grams of azobisisobutyro-nitrile were added. After this addition was completé, reflux was continlIed for aboul: 20 minutes and tlIen over a 3-hour period was added 4060 E rams methyl metIlacrylate, 226 grams of gamma-methacryloxypropyl-trimethoxysilane, 595 grams of the above dispersion stabili~er, 34.0 gr.Illls of mctlIacrylic acid, 34.0 grams of 2-hydroxyeLIlyl ethylenimine, 18.0 grams of a~obisisobutyronitrile and 18 grams of p-octyl mercaptan.
After this addition, reflux was continued for another 1.5 hours and the mixture was then cooled and filtered.
The resultant polymeric dispersion consisting essentially of crosslinked polymer particles (i.e., microgel particles) had a total solids content determined at 150C. of 54.5 percent by weight.
Thc above dispersion was then spray dried to produce a finely divided powder. This powder was then dispersed in an aliphatic hydrocarbon solvent at a 1:1 ratio for use in the examples below.
This example illustrates the preparation of a urethane renction product of the polyurethane coating composition.
The following were charged to a reaction vessel:
Parts by Weight - -Ncopentyl glycol 126.9 TrimetIlylolpropane22.1 ~dipic acid 72.3 lsophthalic acid 123.2 ~i :
l~9ZZ71 This mixture was heated to 200C. for 30 minutes and then at 220C. until the resin had a Gardnér-lloldt viscosity of ~ (60 per-cent solids in methyl ethyl ketone), an acid value of about 10 and a hydroxyl vaLue of about 100. This polyester polyol was then mixed with the following:
Parts by Weight Polyester polyol 70 ~lethyl ethyl ketone 35 ~lethanc-bis(cyclohexyl isocyanate) -(~lobay D-244) 7.13 This mixture was heated at 150C. for 20 hours and then cooled to 120F. for 3 more hours. There were then added 22 parts of n-butanol and 0.3 part of ethanolamine. The product had a Cardner-~loldt viscosity of %l-Z2~ a non-volatile solids content of about 60 percent ~ and an acid value of 3.7.
.' EX~LE 5 This example illustrates the preparation of a pigmented polyurethane coating composition to which the crosslinked poly~erized microparticles are added to form the improved conditions.
A titanium dioxide pigmented polyurethane coating composition was first formulated using the urethane reaction product of Example 4 by blendin~, thc following:
l'nrts by l~eight Urethane reaction product of l,xample 4 204.90 ~utyLated melaminc fomlaldellyde resin 100.80 ~-' ' ', ' ',', ' ' ' ; - ''~' ,'' :' 1~922~1 Parts by ~Jeight C~B* solution 4.2 Pigmcnt paste 396.70 Tinuvin*828 (ultraviolct absorber) 8.5 Cellosolve acetate 18.70 Isobutyl alcohol 30.90 Santo~ ite* 8.5 p-Toluene sulfonic acid 2.80 ; Isobutyl acetate 216.0 Diethanolamine 1.0 * (Trade Mark) 20 percent solution of 1/2 second cellu-lose acetate butyrate in 80/20 toluene/ethanol Tlle pigmcnt paste employed was ground in a solution of a ;.
polyester made from 131 parts of neopentyl glycol, 141 parts of sebacic acid, 174 parts of isophthalic acid, 93.6 parts of trimethylolpropane, and 8.5 parts hydroxyethyl ethylenimine; the paste was produced by mixing the following:
Parts by Wei~ht Polyester (60 percent solids in a 90:10 mixture of xylene and butyl Cellosolve*) 91.80 Poly(oxytetramethylene)glycol 26.20 .~ TiO2 223.30 ` Diacetone alcohol 8.90 Methyl ethyl ketone 26.60 lsobutyl acetate 8.9 Tl~is mixture was ground in a ball mill until the particles ; had a finencss of 7.5 llegman.
* Trade Mark A
- . ~.... . . . - ....... ... .. ... . ~ .
l~9ZZ71 The polyuretllane coating composition thus obtained served - as a control composiLion for the examples below and also as ti~e base com-position to which the crosslinked polymeric microparticles were added.
EX/~IPLE 6 A polyurethane coating composition was preparcd as in ~ample 5 except that the titanium dioxide pigment was replaced by aluminum flake pigment at a level of 3 percent by weigllt. Tlle compo-sition also was utili~ed both as a control composition and as the basic composition to which the crosslinked polymeric microparticles were added.
EXN~PLES 7-8 Tllese examples illustrate tlle improvemcnt in properties obtained by adding the crosslinked polymeric microparticles to polyurethane .
coating compositions.
Parts by Weight Lxample 1 (control) Example 2 . .
Polyurethane of Example 5 200.0 200.0 Ce].led polymcric micro-; particles of Example 3 -- 8.0 Total 200.0 208.0 The above compositions were sprayed onto a panel, flaslled ~or 2 milllltcs aL room tcmperature, at whicll time anotller coat was applicd and flashed for 5 minutes at room temperature and then baked at 250~F. for 30 minutcs to cure.
- 34 ~
. ~ `.
: ' ' '- ''.: ' " ' .. " ,'' . . ' .' :, ' ~ '' ' '. ' lO9ZZ7~
The film build of Example 1 (no crosslinked polymeric micro-particles) was 1.20 mils wllile the film build of ~xample 2 (8 parts crosslinked polymcric micropar~icles) was 1.70 mils. 'rhe flow control of Example 2 was exccllent compared to fair or the film of Example 1.
EXAMPLES 9-lO
Tllesc examples further illustrate ~he effect of tlle crosslinked polymeric microparticles on the properties of polyurcthane coating compositions.
Parts by l~ei~ht Example 3 (control) Example 4 : Polyureth.lne of Example 6 200.0 200.0 Gelled polymeric micro-particles of Lxample 8 -- 8.0 Total 200.0 208.0 These compositions were sprayed onto panels, utilizing the same procedure as in Examples l and 2. The film build of Example 3 (the control) was 1.3 mils while the film build of example 4 was 1.9 mils. The pattern control of Example 3 was fair while that of Example 4 was excellent.
, EX~LE 11 Tllis examplc illustrates the preparatioll of crosslinked poly-mcric micro~ rticles [or usc in l~olycstcr contillg coml)ositlol-s.
To a 5-litcr flask equipped with an up and over condenser, agitator, tllcrmometcr an(l heating mantle were charged 1250 grams of .. , : . . :
.
heptane, 540 grams of Isopar ll (a mixed aliphatic l~ydroearbon having an initial boiling point of 350~. and a dry point of 371P. with 90 percent distilling between 353-357F., available from ~lumble Oil and Refining Conpany), 50 grams of methyl methacrylate, 10 grams of a dispersion stabilizer comprising a 50.3 percent solids solution of 45.4 percent metl~yl metllaerylate, 4.2 percent glycidyl methaerylate, 0.9 pereent metllaerylie acid, and 49.5 percellt of a reaction product of 89. ~ percent poly-12-llydroxystearie aeid and 10.8 percent glyeidyl metllncrylate in a solvent mixture eomprising 52.1 pereent butyl aeetate, 40.0 percent VM&P naplltlla, and 7.9 percent toluene, and 4 grams of azobisisol>utyronitrile. The mixture was heated to reflux (about 103C.) and held for about 3() minutes. Tllen over a period of about 3 hours were 1288 grams of metllyl metllacrylate, 70 grams Or glyeidyl metllacry-late, 42 grams of metl~acrylic acid, 4.2 grams of Armeen DMCD (dimetllyl eoeamine , available f rom ~rmour Chemieal Company), 200 grams of the above dispersion stabilizer, 14 grams of octyl mercaptan and 5.6 grams of azobisisobutyronitrile. l~fter this addition was eompleted, reflux was eontinued for an additional 30 minutes and then an additional 2.8 grams of azobisisobutyronitrile were added. Reflux was then continued Çor another one hour and the mixture was then eooled and filtered.
The resllltallt polymerie dispersion eonsisting essentially of crosslinked polymerie mieropartieles had a total solids content de-termined at 150C. of 44.9 percent by weight .
'.
These examples illustrate the effect of adding the gelled ~ ` --polymerie mleropartieles of Example 11 to an oil-modified polyester. ~ ~ -In the!;e exnmples, a eontrol compositioll eomprisin~ an aluminum pigmented :
.'.. . .. ` :'~ ''' ' ': ". '. ' ; `.` ' '`'' . '. '` '': ' lO9ZZ71 oil-modified polyester coating con1position (Example 12~ and a test coml)osition (l~xample 13) having substantially tllc same composition excer)t tllat it contained approximately 10 percent by weight solids of the crosslin}ced polymeric microparticles of lxample 11 were prepared using standard polyester coating composition mixing procedures.
The compositions had tile following formulations:
Parts by ~eight _~rcdicnLs l:xam~)l c No. 12~:xam~le i~o. L3 Oil-modified polyester resin ( ) 125.0 110.0 Pigment past~ ( ) 10.0 10.0 I'utylate(l melaminc formaldehyde 41.() 41.0 ~;yl ~?11~
Crosslinked polymeric microparticle dispersion of Example 11 ~~ ~~
Total 206.0 25~.0 ( )A 60 percellt solids solution of an oil-modified polyester resin having a hydroxyl value of 76, - an acid value of 9, and a Gardner-~loldt viscosity of V-X, prepared by reacting a monomer mixture consisting of 33.8 percent coconut oil, 38.3 percent phtl-alic anllydride, 2.4 percent tertiary butyl ben~oic acid, 21.6 percent pclltaerytl-ritol and 20.9 percellt trimethyloletllalle in a solvent mixturc consisting of 91 percent xylene and 9 percent n-butanol.
( )A pigment paste consisting of 23.7 percent aluminum flake, 5.9 percent phthalocyanine blue, 16.2 per-cent methyl-1-12-hydroxystearate, 27.1 percent VM&P -naphtha and 27.1 percent methyl ethyl ketone. The ~30 paste was prcpared in conventional manner by grinding on a ball mill until the particles h.ld a filleness of 7.5 llcglllan.
The above compositions were reduce(l to 40 percent total solids witll xylcnc and sprayed onto metal substrates. Example 12, tllc control .~
. .
.
~^
composition, sllowed poor metallic pattern control wl~ Example 13, the composition containing the crosslinked polymeric microparticles showed excellent metallic pattern control.
EXAMPLE~ 14-15 ~-These examples illustrate the effect of adding the crosslinked ; polymeric micropartlcles to an oil-free polyester resin coating com-position. In these examples, a control composition comprising an aluminum pigmented oil-free polyester coating composition (Example 14) and a test composition (~xample 15) having substantially the same composition except that it contained approximately 10 percent by weight solids of the crosslinked polymeric microparticles of Example 11, were prepared utilizing standard polyester coating composition mixing procedures. The compositions had the following formulations:
I'art~s bY Wei~ht _ ~redients ~xample ~o. ~~xample lio. 4 Oil-free polyester resin (1) 125.0 108.0 Pigment paste of Examples 12 and 13 10.0 10.0 Metl~ylolate~ melamine formaldehyde 31.0 31.0 Gellcd polymeric m:icroparticle di~spersion of Example 11 ~ -1 percent SF1023*(anti-cratering agent)( ) 4.0 4.0 p-toluene sulfonic acid 2.0 2.0 ~letllyl-n-bllLyl ketone 86.0 ~1.0 'roL;ll ~5~.0 25~.0 * Trade Mark ., .. . -, : , .
(l)A 60 percent solids solution Or an oil-free polye.ster resill having a hydro~yl value of 74, an acid value of 4 and a Gardller-lloldt vi.scosity of ~ prel)ared by reacting a monomer mixture consisting of 28.6, 1,6-hexanediol, 19.6 percent adipic acid, 33.4 percent is~phthalic acid, 18.0 percent trimethylolpropane and 0.4 percent hydroxy-ethyl ethylenimine in a solvent mixturc consisting of 82.0 percent methyl n-butyl ketone and 18.0 percent toluene.
( ~A l percent solution of silicone in toluene available from the General ~lectric Corporation.
Tlle above compositions were reduced 50 percent by volume to spray using a solvent mixture consistin~ of 75 percent xylene, 10 percent n-butanol and 15 percent Cellosolve acetate and sprayed onto metal substrates. Example 14, the control composition, showed poor metallic pattern control while ~xample 15, the composi~ion containing the-: crosslinked polymeric microparticles, showed excellent metallic pattern contrvl.
~; According to the provisions oE the~Patent Statutes there is described above the invention and what are now considered to be its best embodiments. However, within tlle scope of the appended claims, it is to be understood that the invention can be practiced otherwise ; than as specifically described.
`::
' , , " , ' '.
,
, solution comprising 52.1 pcrcent butyl acetate, 40.0 pcrcent VM&P
naphtha, and 7.9 percent toluene, and 14.3 grams of azobisisobutyro-nitrile were added. After this addition was completé, reflux was continlIed for aboul: 20 minutes and tlIen over a 3-hour period was added 4060 E rams methyl metIlacrylate, 226 grams of gamma-methacryloxypropyl-trimethoxysilane, 595 grams of the above dispersion stabili~er, 34.0 gr.Illls of mctlIacrylic acid, 34.0 grams of 2-hydroxyeLIlyl ethylenimine, 18.0 grams of a~obisisobutyronitrile and 18 grams of p-octyl mercaptan.
After this addition, reflux was continued for another 1.5 hours and the mixture was then cooled and filtered.
The resultant polymeric dispersion consisting essentially of crosslinked polymer particles (i.e., microgel particles) had a total solids content determined at 150C. of 54.5 percent by weight.
Thc above dispersion was then spray dried to produce a finely divided powder. This powder was then dispersed in an aliphatic hydrocarbon solvent at a 1:1 ratio for use in the examples below.
This example illustrates the preparation of a urethane renction product of the polyurethane coating composition.
The following were charged to a reaction vessel:
Parts by Weight - -Ncopentyl glycol 126.9 TrimetIlylolpropane22.1 ~dipic acid 72.3 lsophthalic acid 123.2 ~i :
l~9ZZ71 This mixture was heated to 200C. for 30 minutes and then at 220C. until the resin had a Gardnér-lloldt viscosity of ~ (60 per-cent solids in methyl ethyl ketone), an acid value of about 10 and a hydroxyl vaLue of about 100. This polyester polyol was then mixed with the following:
Parts by Weight Polyester polyol 70 ~lethyl ethyl ketone 35 ~lethanc-bis(cyclohexyl isocyanate) -(~lobay D-244) 7.13 This mixture was heated at 150C. for 20 hours and then cooled to 120F. for 3 more hours. There were then added 22 parts of n-butanol and 0.3 part of ethanolamine. The product had a Cardner-~loldt viscosity of %l-Z2~ a non-volatile solids content of about 60 percent ~ and an acid value of 3.7.
.' EX~LE 5 This example illustrates the preparation of a pigmented polyurethane coating composition to which the crosslinked poly~erized microparticles are added to form the improved conditions.
A titanium dioxide pigmented polyurethane coating composition was first formulated using the urethane reaction product of Example 4 by blendin~, thc following:
l'nrts by l~eight Urethane reaction product of l,xample 4 204.90 ~utyLated melaminc fomlaldellyde resin 100.80 ~-' ' ', ' ',', ' ' ' ; - ''~' ,'' :' 1~922~1 Parts by ~Jeight C~B* solution 4.2 Pigmcnt paste 396.70 Tinuvin*828 (ultraviolct absorber) 8.5 Cellosolve acetate 18.70 Isobutyl alcohol 30.90 Santo~ ite* 8.5 p-Toluene sulfonic acid 2.80 ; Isobutyl acetate 216.0 Diethanolamine 1.0 * (Trade Mark) 20 percent solution of 1/2 second cellu-lose acetate butyrate in 80/20 toluene/ethanol Tlle pigmcnt paste employed was ground in a solution of a ;.
polyester made from 131 parts of neopentyl glycol, 141 parts of sebacic acid, 174 parts of isophthalic acid, 93.6 parts of trimethylolpropane, and 8.5 parts hydroxyethyl ethylenimine; the paste was produced by mixing the following:
Parts by Wei~ht Polyester (60 percent solids in a 90:10 mixture of xylene and butyl Cellosolve*) 91.80 Poly(oxytetramethylene)glycol 26.20 .~ TiO2 223.30 ` Diacetone alcohol 8.90 Methyl ethyl ketone 26.60 lsobutyl acetate 8.9 Tl~is mixture was ground in a ball mill until the particles ; had a finencss of 7.5 llegman.
* Trade Mark A
- . ~.... . . . - ....... ... .. ... . ~ .
l~9ZZ71 The polyuretllane coating composition thus obtained served - as a control composiLion for the examples below and also as ti~e base com-position to which the crosslinked polymeric microparticles were added.
EX/~IPLE 6 A polyurethane coating composition was preparcd as in ~ample 5 except that the titanium dioxide pigment was replaced by aluminum flake pigment at a level of 3 percent by weigllt. Tlle compo-sition also was utili~ed both as a control composition and as the basic composition to which the crosslinked polymeric microparticles were added.
EXN~PLES 7-8 Tllese examples illustrate tlle improvemcnt in properties obtained by adding the crosslinked polymeric microparticles to polyurethane .
coating compositions.
Parts by Weight Lxample 1 (control) Example 2 . .
Polyurethane of Example 5 200.0 200.0 Ce].led polymcric micro-; particles of Example 3 -- 8.0 Total 200.0 208.0 The above compositions were sprayed onto a panel, flaslled ~or 2 milllltcs aL room tcmperature, at whicll time anotller coat was applicd and flashed for 5 minutes at room temperature and then baked at 250~F. for 30 minutcs to cure.
- 34 ~
. ~ `.
: ' ' '- ''.: ' " ' .. " ,'' . . ' .' :, ' ~ '' ' '. ' lO9ZZ7~
The film build of Example 1 (no crosslinked polymeric micro-particles) was 1.20 mils wllile the film build of ~xample 2 (8 parts crosslinked polymcric micropar~icles) was 1.70 mils. 'rhe flow control of Example 2 was exccllent compared to fair or the film of Example 1.
EXAMPLES 9-lO
Tllesc examples further illustrate ~he effect of tlle crosslinked polymeric microparticles on the properties of polyurcthane coating compositions.
Parts by l~ei~ht Example 3 (control) Example 4 : Polyureth.lne of Example 6 200.0 200.0 Gelled polymeric micro-particles of Lxample 8 -- 8.0 Total 200.0 208.0 These compositions were sprayed onto panels, utilizing the same procedure as in Examples l and 2. The film build of Example 3 (the control) was 1.3 mils while the film build of example 4 was 1.9 mils. The pattern control of Example 3 was fair while that of Example 4 was excellent.
, EX~LE 11 Tllis examplc illustrates the preparatioll of crosslinked poly-mcric micro~ rticles [or usc in l~olycstcr contillg coml)ositlol-s.
To a 5-litcr flask equipped with an up and over condenser, agitator, tllcrmometcr an(l heating mantle were charged 1250 grams of .. , : . . :
.
heptane, 540 grams of Isopar ll (a mixed aliphatic l~ydroearbon having an initial boiling point of 350~. and a dry point of 371P. with 90 percent distilling between 353-357F., available from ~lumble Oil and Refining Conpany), 50 grams of methyl methacrylate, 10 grams of a dispersion stabilizer comprising a 50.3 percent solids solution of 45.4 percent metl~yl metllaerylate, 4.2 percent glycidyl methaerylate, 0.9 pereent metllaerylie acid, and 49.5 percellt of a reaction product of 89. ~ percent poly-12-llydroxystearie aeid and 10.8 percent glyeidyl metllncrylate in a solvent mixture eomprising 52.1 pereent butyl aeetate, 40.0 percent VM&P naplltlla, and 7.9 percent toluene, and 4 grams of azobisisol>utyronitrile. The mixture was heated to reflux (about 103C.) and held for about 3() minutes. Tllen over a period of about 3 hours were 1288 grams of metllyl metllacrylate, 70 grams Or glyeidyl metllacry-late, 42 grams of metl~acrylic acid, 4.2 grams of Armeen DMCD (dimetllyl eoeamine , available f rom ~rmour Chemieal Company), 200 grams of the above dispersion stabilizer, 14 grams of octyl mercaptan and 5.6 grams of azobisisobutyronitrile. l~fter this addition was eompleted, reflux was eontinued for an additional 30 minutes and then an additional 2.8 grams of azobisisobutyronitrile were added. Reflux was then continued Çor another one hour and the mixture was then eooled and filtered.
The resllltallt polymerie dispersion eonsisting essentially of crosslinked polymerie mieropartieles had a total solids content de-termined at 150C. of 44.9 percent by weight .
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These examples illustrate the effect of adding the gelled ~ ` --polymerie mleropartieles of Example 11 to an oil-modified polyester. ~ ~ -In the!;e exnmples, a eontrol compositioll eomprisin~ an aluminum pigmented :
.'.. . .. ` :'~ ''' ' ': ". '. ' ; `.` ' '`'' . '. '` '': ' lO9ZZ71 oil-modified polyester coating con1position (Example 12~ and a test coml)osition (l~xample 13) having substantially tllc same composition excer)t tllat it contained approximately 10 percent by weight solids of the crosslin}ced polymeric microparticles of lxample 11 were prepared using standard polyester coating composition mixing procedures.
The compositions had tile following formulations:
Parts by ~eight _~rcdicnLs l:xam~)l c No. 12~:xam~le i~o. L3 Oil-modified polyester resin ( ) 125.0 110.0 Pigment past~ ( ) 10.0 10.0 I'utylate(l melaminc formaldehyde 41.() 41.0 ~;yl ~?11~
Crosslinked polymeric microparticle dispersion of Example 11 ~~ ~~
Total 206.0 25~.0 ( )A 60 percellt solids solution of an oil-modified polyester resin having a hydroxyl value of 76, - an acid value of 9, and a Gardner-~loldt viscosity of V-X, prepared by reacting a monomer mixture consisting of 33.8 percent coconut oil, 38.3 percent phtl-alic anllydride, 2.4 percent tertiary butyl ben~oic acid, 21.6 percent pclltaerytl-ritol and 20.9 percellt trimethyloletllalle in a solvent mixturc consisting of 91 percent xylene and 9 percent n-butanol.
( )A pigment paste consisting of 23.7 percent aluminum flake, 5.9 percent phthalocyanine blue, 16.2 per-cent methyl-1-12-hydroxystearate, 27.1 percent VM&P -naphtha and 27.1 percent methyl ethyl ketone. The ~30 paste was prcpared in conventional manner by grinding on a ball mill until the particles h.ld a filleness of 7.5 llcglllan.
The above compositions were reduce(l to 40 percent total solids witll xylcnc and sprayed onto metal substrates. Example 12, tllc control .~
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composition, sllowed poor metallic pattern control wl~ Example 13, the composition containing the crosslinked polymeric microparticles showed excellent metallic pattern control.
EXAMPLE~ 14-15 ~-These examples illustrate the effect of adding the crosslinked ; polymeric micropartlcles to an oil-free polyester resin coating com-position. In these examples, a control composition comprising an aluminum pigmented oil-free polyester coating composition (Example 14) and a test composition (~xample 15) having substantially the same composition except that it contained approximately 10 percent by weight solids of the crosslinked polymeric microparticles of Example 11, were prepared utilizing standard polyester coating composition mixing procedures. The compositions had the following formulations:
I'art~s bY Wei~ht _ ~redients ~xample ~o. ~~xample lio. 4 Oil-free polyester resin (1) 125.0 108.0 Pigment paste of Examples 12 and 13 10.0 10.0 Metl~ylolate~ melamine formaldehyde 31.0 31.0 Gellcd polymeric m:icroparticle di~spersion of Example 11 ~ -1 percent SF1023*(anti-cratering agent)( ) 4.0 4.0 p-toluene sulfonic acid 2.0 2.0 ~letllyl-n-bllLyl ketone 86.0 ~1.0 'roL;ll ~5~.0 25~.0 * Trade Mark ., .. . -, : , .
(l)A 60 percent solids solution Or an oil-free polye.ster resill having a hydro~yl value of 74, an acid value of 4 and a Gardller-lloldt vi.scosity of ~ prel)ared by reacting a monomer mixture consisting of 28.6, 1,6-hexanediol, 19.6 percent adipic acid, 33.4 percent is~phthalic acid, 18.0 percent trimethylolpropane and 0.4 percent hydroxy-ethyl ethylenimine in a solvent mixturc consisting of 82.0 percent methyl n-butyl ketone and 18.0 percent toluene.
( ~A l percent solution of silicone in toluene available from the General ~lectric Corporation.
Tlle above compositions were reduced 50 percent by volume to spray using a solvent mixture consistin~ of 75 percent xylene, 10 percent n-butanol and 15 percent Cellosolve acetate and sprayed onto metal substrates. Example 14, the control composition, showed poor metallic pattern control while ~xample 15, the composi~ion containing the-: crosslinked polymeric microparticles, showed excellent metallic pattern contrvl.
~; According to the provisions oE the~Patent Statutes there is described above the invention and what are now considered to be its best embodiments. However, within tlle scope of the appended claims, it is to be understood that the invention can be practiced otherwise ; than as specifically described.
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Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of producing a dispersion containing a relatively high concentration of non-rubbery crosslinked acrylic polymer microparticles having a particle size of from 0.1 to 10 microns, said method comprising free radical addition copolymerizing from about 0.5 to 15 percent of alpha, beta-ethyleni-cally unsaturated monocarboxylic acid, from about 70 to 99 percent of at least one other copolymerizable ethylenically unsaturated monomer and from about 0.5 to 15 percent of crosslinking monomer selected from the group consisting of (1) epoxy group-containing compound and (2) a mixture of alkylenimine and organoalkoxysilane, wherein:
a. said epoxy group-containing compound is monoepoxide compound which additionally contains ethylenic unsaturation.
b. said organoalkoxysilane is selected from the group con-sisting of acrylatoalkoxysilane, methacrylatoalkoxysilane and vinylalkoxysilane, and c. said monomer percentages are based on the weight of monomers used in the copolymerization process, in the presence of hydrocarbon dispersing liquid which is a solvent for the polymerizable monomers but a non-solvent for the resultant polymer, and polymeric dispersion stabilizer containing at least two segments of which one segment is solvated by said dispersing liquid and a second segment is of different polarity than said first segment and is relatively insoluble in said dispersing liquid, wherein the reaction is carried out at elevated temperature such that the dispersion polymer first forms and then is crosslinked.
a. said epoxy group-containing compound is monoepoxide compound which additionally contains ethylenic unsaturation.
b. said organoalkoxysilane is selected from the group con-sisting of acrylatoalkoxysilane, methacrylatoalkoxysilane and vinylalkoxysilane, and c. said monomer percentages are based on the weight of monomers used in the copolymerization process, in the presence of hydrocarbon dispersing liquid which is a solvent for the polymerizable monomers but a non-solvent for the resultant polymer, and polymeric dispersion stabilizer containing at least two segments of which one segment is solvated by said dispersing liquid and a second segment is of different polarity than said first segment and is relatively insoluble in said dispersing liquid, wherein the reaction is carried out at elevated temperature such that the dispersion polymer first forms and then is crosslinked.
2. The method of Claim 1 wherein the alpha, beta-ethylenically unsaturated monocarboxylic acid is acrylic acid or methacrylic acid.
3. The method of Claim 1 wherein said other copolymerizable ethylenically-unsaturated monomer is methyl methacrylate.
4. The method of Claim 1 wherein the crosslinking monomer is glycidyl methacrylate.
5. The method of Claim 1 wherein the crosslinking monomers are a mixture of an alkylenimine and an organoalkoxysilane of the group acrylato-alkoxysilane, methacrylatoalkoxysilane and vinylalkoxysilane.
6. The method of Claim 5 wherein the crosslinking monomers are a mixture of hydroxyethyl ethylenimine and gamma-methacryloxypropyltrimethoxy-silane.
7. The method of Claim 1 wherein the dispersion stabilizer is a graft copolymer containing two polymeric segments of which one segment is solvated by said dispersing liquid and the second segment is an anchor polymer of different polarity to said first segment and is relatively non-solvatable by said dispersing liquid and wherein said dispersion stabilizer contains pendant groups which have been addition copolymerized with said ethylenically unsaturated monomers.
8. The method of Claim 7 wherein the dispersion stabilizer is formed by graft copolymerizing the reaction product of glycidyl methacrylate and poly-(12-hydroxystearic acid), with methyl methacrylate and glycidyl methacrylate and the resulting copolymer product containing pendant epoxy groups is reacted with methacrylic acid.
9. The method of Claim 1 wherein said ethylenically-unsaturated monomer is methyl methacrylate, said monocarboxylic acid is methacrylic acid, and said crosslinking monomer is a mixture of gamma-methacryloxypropyltri-methoxysilane and hydroxyethyl ethylenimine.
10. The method of Claim 1 wherein said other ethylenically-unsaturated monomer is methyl methacrylate, said monocarboxylic acid is methacrylic acid and said crosslinking monomer is glycidyl methacrylate.
11. Non-rubbery crosslinked acrylic polymer microparticles having a particle size of from 0.1 to 10 microns formed by the free radical addition copolymeri-zation of from 0.5 to 15 percent of an alpha, beta-ethylenically unsaturated monocarboxylic acid, from about 70 to 99 percent of at least one other copolymerizable ethylenically unsaturated monomer, and from 0.5 percent to 15 percent of a crosslinking monomer selected from the group consisting of (1) epoxy-group containing compound and (2) a mixture of alkylenimine and organoalkoxysilane, wherein:
a. said epoxy group-containing compound is monoepoxide compound which additionally contains ethylenic unsaturation, b. said organoalkoxysilane is selected from the group con-sisting of acrylatoalkoxysilane, methacrylatoalkoxysilane, and vinylalkoxysilane, and c. said monomer percentages are based on the weight of monomers used in the copolymerization process, in the presence of hydrocarbon dispersing liquid which is a solvent for the polymerizable monomers but a non-solvent for the resultant polymer, and polymeric dispersion stabilizer containing at least two segments of which one segment is solvated by said dispersing liquid and a second segment is of different polarity than said first segment and is relatively insoluble in said dispersing liquid, the reaction having been carried out at elevated temperature such that the polymeric microparticles first form and then are crosslinked.
a. said epoxy group-containing compound is monoepoxide compound which additionally contains ethylenic unsaturation, b. said organoalkoxysilane is selected from the group con-sisting of acrylatoalkoxysilane, methacrylatoalkoxysilane, and vinylalkoxysilane, and c. said monomer percentages are based on the weight of monomers used in the copolymerization process, in the presence of hydrocarbon dispersing liquid which is a solvent for the polymerizable monomers but a non-solvent for the resultant polymer, and polymeric dispersion stabilizer containing at least two segments of which one segment is solvated by said dispersing liquid and a second segment is of different polarity than said first segment and is relatively insoluble in said dispersing liquid, the reaction having been carried out at elevated temperature such that the polymeric microparticles first form and then are crosslinked.
12. The non-rubbery crosslinked acrylic polymer microparticles of Claim 11 wherein said dispersion stabilizer is a graft copolymer containing two polymeric segments of which one segment is solvated by said dispersing liquid and the second segment is an anchor polymer of different polarity to said first segment and is relatively non-solvatable by said dispersing liquid and wherein said dispersion stabilizer contains pendant groups which have been addition copolymerized with said ethylenically unsaturated monomers.
13. The non-rubbery crosslinked acrylic polymer microparticles of Claim 12 wherein said dispersion stabilizer is formed by graft copolymerizing the reaction product of glycidyl methacrylate and poly-(12-hydroxystearic acid), with methyl methacrylate and glycidyl methacrylate and the resulting copolymer product containing pendant epoxy groups is reacted with methacrylic acid.
14. The non-rubbery crosslinked acrylic polymer microparticles of Claim 11 wherein said monocarboxylic acid is methacrylic acid, said other unsaturated monomer is methyl methacrylate and said crosslinking monomer is glycidyl methacrylate.
15. The non-rubbery crosslinked acrylic polymer microparticles of Claim 11 wherein said monocarboxylic acid is methacrylic acid, said other unsaturated monomer is methyl methacrylate and said crosslinking monomer is a mixture of hydroxyethyl ethylenimine and gamma-methacryloxy propyltrimethoxysilane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA298,122A CA1092271A (en) | 1975-03-19 | 1978-03-03 | Preparation of high concentration dispersions of cross-linked acrylic polymer microparticles |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US55994975A | 1975-03-19 | 1975-03-19 | |
| US559,949 | 1975-03-19 | ||
| CA243,461A CA1064637A (en) | 1975-03-19 | 1976-01-13 | Method of preparing gelled polymeric microparticles, product produced thereby, and compositions containing the same |
| CA298,122A CA1092271A (en) | 1975-03-19 | 1978-03-03 | Preparation of high concentration dispersions of cross-linked acrylic polymer microparticles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1092271A true CA1092271A (en) | 1980-12-23 |
Family
ID=27164277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA298,122A Expired CA1092271A (en) | 1975-03-19 | 1978-03-03 | Preparation of high concentration dispersions of cross-linked acrylic polymer microparticles |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1092271A (en) |
-
1978
- 1978-03-03 CA CA298,122A patent/CA1092271A/en not_active Expired
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