CA2018587A1 - Coating material, process for the preparation of coatings and substrates coated therewith - Google Patents
Coating material, process for the preparation of coatings and substrates coated therewithInfo
- Publication number
- CA2018587A1 CA2018587A1 CA002018587A CA2018587A CA2018587A1 CA 2018587 A1 CA2018587 A1 CA 2018587A1 CA 002018587 A CA002018587 A CA 002018587A CA 2018587 A CA2018587 A CA 2018587A CA 2018587 A1 CA2018587 A1 CA 2018587A1
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- Prior art keywords
- coating material
- weight
- cellulose ester
- coatings
- appropriate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D101/00—Coating compositions based on cellulose, modified cellulose, or cellulose derivatives
- C09D101/08—Cellulose derivatives
- C09D101/32—Cellulose ether-esters
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D201/00—Coating compositions based on unspecified macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/80—Processes for incorporating ingredients
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Paints Or Removers (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
Abstract of the disclosure Coating material, process for the preparation of coatings and substrates coated therewith The invention relates to a coating material for the preparation of coatings, in particular multi-layer paint coatings composed of at least one base layer and, if appropriate, at least one transparent cover coat, the coating material containing film-forming resin (A), cellulose esters (B), solvents (C), metallic pigments (D) and, if appropriate, crosslinking agents (E) and also, if appropriate, further paint additives (F), wherein the cellulose ester (B) has an acetyl content of 2.0 to 30 %
by weight, a butyryl content of 17 to 53 % by weight and an average molecular weight M? of at least 25,000, this cellulose ester (B) having been introduced into the coating material in the form of a pasty, thixotropic premix.
The invention also relates to a process for the prepar-ation of a multi-layer coating and to the substrates thus coated.
The coating materials according to the invention are distinguished, inter alia, by high solids contents at low viscosities, and afford coatings with fault-free metallic effects.
by weight, a butyryl content of 17 to 53 % by weight and an average molecular weight M? of at least 25,000, this cellulose ester (B) having been introduced into the coating material in the form of a pasty, thixotropic premix.
The invention also relates to a process for the prepar-ation of a multi-layer coating and to the substrates thus coated.
The coating materials according to the invention are distinguished, inter alia, by high solids contents at low viscosities, and afford coatings with fault-free metallic effects.
Description
213 l~i8r~
HOECHST AKTIENGESELLS~HAFT HO~ 89/F 174 Dr. ZR/sch Description Coating material, process for the preparation of coatings and 8ubstrate8 coated therewit]h The importance of metallic paints in the automobile industry has increased greatly in xecent years. Whereas earlier a large fraction of coachworks was treated with one-layer metallic paints, nowadays automobile6 are painted virtually exclusivPly by the multi(2)-layer metallic process, the so-called "wet-on-wet process". In this process a base paint which dries essentially by physical means and which is pigmented with aluminium, to which other coloring pigments may first be added, and then, after brief exposure to air, a clear lacquer is applied as a finish. Thiæ base paint consists mainly of organic solvent, a binder which dries by physical means, such as a cellulose ester, in particular cellulose acetobutyrate ~CAB), a film-forming resin, such as an oil-free polyester, a crosslinking agent, ~uch as a melamine resin, and pigments (cf., inter alia, German Offenlegungsschrift 1,949,372). A well as a more rapid physical drying of the paint film, the cellulose esterl inter alia, also produces an improvement in the metallic effect. Considerable amoun~s of the cellulose e~ter, which is soluble in base paint solvents, are, howe~ver, required for this purpose.
Apart from aluminum and Iriodin, the pi~ments used are both inorganic pigments, such as titanium dioxide and iron oxides, and organic pigments, such as phthalocyan-ines, quinacridones and/or halogenated thioindigo pig-ments. The solids content of the base paints, which is in most cases around 15 %, is fairly low. The remainder is volatile ~olvent, composed for the most part of esters, such as ethylene glycol monoethyl ether acetate, butyl acetate and ethyl acetate, and aromatic compounds, such as toluene or xylene.
HOECHST AKTIENGESELLS~HAFT HO~ 89/F 174 Dr. ZR/sch Description Coating material, process for the preparation of coatings and 8ubstrate8 coated therewit]h The importance of metallic paints in the automobile industry has increased greatly in xecent years. Whereas earlier a large fraction of coachworks was treated with one-layer metallic paints, nowadays automobile6 are painted virtually exclusivPly by the multi(2)-layer metallic process, the so-called "wet-on-wet process". In this process a base paint which dries essentially by physical means and which is pigmented with aluminium, to which other coloring pigments may first be added, and then, after brief exposure to air, a clear lacquer is applied as a finish. Thiæ base paint consists mainly of organic solvent, a binder which dries by physical means, such as a cellulose ester, in particular cellulose acetobutyrate ~CAB), a film-forming resin, such as an oil-free polyester, a crosslinking agent, ~uch as a melamine resin, and pigments (cf., inter alia, German Offenlegungsschrift 1,949,372). A well as a more rapid physical drying of the paint film, the cellulose esterl inter alia, also produces an improvement in the metallic effect. Considerable amoun~s of the cellulose e~ter, which is soluble in base paint solvents, are, howe~ver, required for this purpose.
Apart from aluminum and Iriodin, the pi~ments used are both inorganic pigments, such as titanium dioxide and iron oxides, and organic pigments, such as phthalocyan-ines, quinacridones and/or halogenated thioindigo pig-ments. The solids content of the base paints, which is in most cases around 15 %, is fairly low. The remainder is volatile ~olvent, composed for the most part of esters, such as ethylene glycol monoethyl ether acetate, butyl acetate and ethyl acetate, and aromatic compounds, such as toluene or xylene.
2 (3 ~ 7 The second layer, applied after a time of exposure of air of only a few minutes, is a clear lacquer which can be an air-drying or artifically dried lacquer, such as r for instance, in the case of coachwork repair, or a baking lacquer, such as is used in conveyor belt automotive painting. In the latter case both coat~ of paint are cured together under the customary baking conditions (10 to 30 minutes at 120 to 150C). The hi~h content of solvent in the base paint con6titutes considerable pollution for the environment and, in addition, also results in corresponding expense, i.e. the additional charge caused by the use of solvents and their removal 80 as to protect the en~ironment.
There has, therefore, been no lack of attempts to in-crease ths solids content or to reduce the proportion of volatile solvents. In the course of this it has been found that paints having a solids content increased in the customary manner have too high a vi6cosity, ~an only be applied with difficulty and result in paint layers having unsatisfactory technical properties in use. ~his route to the preparation o~ paints, in particular base paints, which are le~s harmful to the environment and, as a result of the higher solids content, are more product-ive and hence economical, cannot therefore be taken.
The invention therefore relates to a coating material for the preparation of coatings, in particular ~ulti-layer paint coatings composed of at least one ba~e layer and, if appropriate, at least one transparent top coat, the coating material containing film-forming resin~ (A), cellulose esters ~B), solvellts (C), preferably metallic pi~ments (D~ and, if appropriate, crosslinking sgent~ (E) and also, if appropriate, further paint addi~ives (F), wherein the cellulose ester (B) has an acetyl content of 2.0 to 30 ~ by weight, a butyryl content of 17 to 53 ~ by weight and an average molecular weight k~ of at least 25,000, this cellulose ester (B) having been introduced into the coating material in the form of a pasty, 8 ~ ~ 7 thixotropic premix.
The invention also relates ~o a process for the prepar-ation of a multi-layer coa~inS~ using this coating mater-ial and to the substrates thus l~oated.
It was surprising and not to be foreseen that, in the coating material according to the invention, the amount of cellulose ester can be reduced from the approx 40 ~
hitherto customary to about one half. This makes p~ssible an increase in the ~olids content from approx. 15 % to approx. 30 %, preferably 26 ~, and hence a considerable saving of solvent. It was al~o surprising that a paint of such a composition has a low viscosity, in spite of its high solids content; it can therefore be applied without difficulties and, in ~he case of a metallic paint, produces a fault~free metal effect. As a result of the special rheological behavior and the rapid drying, there is also no sagging on vertical suraces and no blushing~
In the case of a mul~i~layer paint coat it is also possible to overpaint without difficulties even after a few minutes dryins~ at room temperature, i.e. no in~ipient dissolution of the incipiently dried base paint takes place as a result of the finish applied later. In gener-al, ~he tLme of exposure to air after which the layer of base paint can be o~erpainted is 2 to 10 minutes, prefer-ably 3 to 6 minutes, at 15 to 30DC, preferably 20 to 25C.
The cellulose ester (B) is preferably cellulose aceto-butyrate; in addition cellulose propionate, cellulo~e butyrate and cellulose acetopropionate and al~o mixtures of the various cellulose esters are also 6uitable. The cellulose acetobutyrate which is preferably employed has an acetyl content of 2 to 5 % by weight, particularly 3 to 5 % by weis~ht, and a butyryl content of, preferably, 47 to 53 ~ by weight, especially 50 to 52 ~ by weight.
The hydroxyl c:ontent is usually 0 5 ~o 1.8 ~ by weight, preferably 0.6 to 1.0 ~ by weight. The average molecular weight Mn preferably has values between 30,000 and 60,000, especially between 54,000 and 60,000.
The amount of cellulose ester (B) in the coatin~ material is generally 0.5 to 6, pxaferably 1 to 3, % by weight, relative to the sum of (A) and (B) and also, if appropri-ate, (~) (solids content). ~rhe cellulose e~ter (B) according to the invention can also, if appropriate, be employed as a mixture with conventional cellulose e~ter~, for example those described in German Offenlegungs6chrift 1,949,372 which was mentioned initially.
In accordance with the invention the cellulose ester (B) is added to the coating material in the form of a pasty (viscous), thixotropic premix (master bakch) which preferably has a gelatinous consistency. In addition to the cellulose ester, this premix contains a diluen which essentially swells the cellulose ester only incipiently.
The boiling point (under normal pressure) of this diluent is generally at least 70~C, preferably between 70 and 250C. Examples of these diluents are aromatic or ali-phatic hydrocarbons, such as ben2ene, toluene, thevarious xylenes, higher-boiling mineral oil fractions, such as ~)Solvesso, higher alcohols having at least 4 carbon atoms, preferably 4 to 10 carbon atoms, such as n-butanol, isobutanol, pentanols, hexanols etc. or corresponding mixtures. ~he amount of cellulose ster (B) in this premix i8 usually l to 10 % by weight, preferably 2 to 6 % by weight, relative to this premix.
In a further embodiment this premix also contains, în addition, polymers or prepol~mers, especially tho~e which are in any case used in the coating material according tD
the invention. These polymers/prepolymers can be at least partly soluble in the diluent used for the premi~.
E~amples of pol~mers/prepolymers of this type are, intex alia, customary ~mino resins, such as polycondensates formed from melamine, benzoguanamine and/or ur~a with formaldehyde which are etherified, for example with monoalcohols, e~amples of suitable monoalcohols being (3 ~ ~ 7 methanol, ethanol, propanol or butanol. Methylated, propylated or butylated methylolmelamine may be men~ioned here. Further examples are polyester resins, preferably free from oil, and acrylate re~ins.
This premix is prepared by combining the cellulose ester (B) with the other constituent(s) of the mixture for 30 to 180 minutes, preferably 100 to 140 minllte~, at an elevated temperature, the :Level of the temperature under normal conditions being at least 70C, preferably between 70 and 250C.
Suitable film-foxmin~ resins (A), the average molecular weights M~ ~determined by gel permeation chromatography aga.inst a polystyrene standard) of which are usually within the range from about 500 to 50,000, preferably about 1,000 to 20,000, are the pol~mers known for this purpose which contain active groups for crosslinking, above all hydroxyl and/or amino groups. Ex2mples of these are synthetic resins (polyols) containing OH groups, such as polyether-polyols, polyacetal-polyols, polyester-amide polyols, epoxy resin polyols or reaction products thereof with CO2, phenolic resin polyols, polyurea-polyols, polyurethane-polyGls, partly saponified homopolymers and copolymers of vinyl esters, partly acetalized polyvinyl alcohols, polyester-polyols or acrylate resin polyols.
Phenolic, urea or melamine resins containing OH are also suitable in this respect. Polyols of this type, which can also be employed as a mixture, are described, for example, in German Offenlegungsschriften 2,314,513 and 3,124,784 and in European Published Applications 123,880 and 189,728. Other resins (A~ for the base paint which are suitable according to the invention are also dis-closed, for example~ in German Offenlegun~sschriften 1,949,372, ~,818,093, 2,818,100 and 3,720,984 and European Published Applications 5,428 and 80,340.
Epoxy resin polyols, polyester-polyols, polyuxethane-polyols, polyether-polyols and acrylate resin polyols are preferred.
In one embodiment of the invention these film-forming resins can be self-curing because, for example, some of the hydroxyl groups have been reacted w:ith partly masked isocyanates.
The amount of component (A) in the coating material according to the invention is generally between and 90 % by weight, preferably betwsen 5 and 30 % by weight, relative to the coating material.
Sui.table solvents (C) are, above all, (cyclo)aliphatic and/or aromatic hydrocarbons, ~uch as hexane~ heptane, cyclohexane, benzene, toluene, the various xylenes and aromatic solvents within a boiling range of approx. 150 to 180C (higher-boiling mineral oil fraction~, such as ~R~Solvesso); also halogenated hydrocarbons, ethers and glycol ethers, such as diethyl ether, 1,2-dLmetho~y-ethane, ethylene glycol dibutyl e~her, tetrahydrofuran or dioxane; ketones, such as, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like; esters, such as ethyl acetate, butyl acetate/
ethylene glycol monoethyl ether acetate and methoxypropyl acetate; N-methylpyrrolidone; monohydric or polyhydric alcohols, such as butanol, ethylene glycol monoethyl-(butyl~ ether etc~ The amount of this solvent should be such that the coating material can be handled in an optimum manner depending on the method of application chosen and that the paint films applied level out to an adequate extent. In general, amounts of 70 to 85, prefer-ably 70 to 80, % by weight, relative to the coating material, are sufficient for this.
The coating materials according to the invention contain - if appropr:iate as well as customary non-metallic (colored) pigments (in this regard see under (F) below) -metallic pi~ments (D), preferably in powder form, on their own or as a mi~ture, such as aluminum bronzes or copper bron~es, preferably aluminum powder. The amount thereof is generally 0.5 to 60, preferably 0.5 to 40, ~
:
2 ~
by weight, relative to (A).
These metallic pigments are advantageously incorporated into the coating material in the form of pigment pastes.
In addition to the metallic pigment and sol~ent, this pigment paste contains a so-c:alled grinding resin or paste resin, such as polyesters or acrylic resin~.
The grinding resin can often be equivalent to the film-forming resin (A).
Suitable crosslinking agents (E) - in the event that (A) is not self-curing - are the curing agents customary for extraneously crosslinking two-component lac~uers, for example amino resins, such as melamine/formaldehyde, benzoguanamine/formaldehyde~ ureatformaldehyde or thio-urea/formaldehyde condensates, in particular melamine/
formaldehyde condensates which have been etherified with alkanols; also phenolic resins, (masked) polyisocyanates, ~-hydroxyesters of polycarboxylic acids, poly~ hydroxy-urethanes), polyepoxide compounds, reaction products of dialkylmalona~es with aldehydes and ketones which react with the elimination of water to give unsaturated dicar-boxylic acid esters (Knoevenagel æynthesis), transesteri-fication or transamidation curing agents and also Michael addition products, for example those described in German Offenlegungsschriften 3,315,469, 3,417,441 and 3,436,345.
The crosslinking agents (E) are usually employed in amounts of 5 to 90 ~ by weight, preferably 10 to 70 % by weight, relative to the film-forming resin (~.
Exampl~s of customary paint additives (F) which can, if appropriate, be present in the coating material according to the invention are (colored) pigments and fillers and also paint auxiliaries, for example anti-settling agents, foaming agents and/or wetting agents, levelling agents, reactive thin:ners, plasticiæers, stabilizers, catalysts, rheology auxiliaries ~such as microgels or polyurea derivatives) and the like. At least some of these 20~53~87 additives can be added to the coating material aæ late as immediately before processing.
Addition to the individual components or to the whole mixture is also possible. The selection and the S proportionation of these substcmces are known to ~hose skilled in the art.
Iron oxides (iron red or iron black), lead vxides, lead silicates, titanium dioxide, z.inc oxide, ~inc sul~ide, chrome-titanium yellow, ultramarine blue, carbon black, phthalocyanine complexes, quinacridone~, halogenated thioindigo pigments, ~lavanthrone yellow, indanthrone blue, perylene red etc. and also effect pigments, such as Iriodin, should be mentioned as examples of (colored) pigments, which can have an inorganic or organic nature.
These pigments are usually employed in amounts of 0.1 to 20, preferably 0.5 to 5, % by weight, relative to component (A).
The total solids content (including the metallic pig-ments (D) and the paint additives (F)~ in the coating materials according to the invention i8 generally 10 to 30 % by weight, preferably 15 to 30 % by weight and particularly 20 to 30 ~ by weight (120C/1 hour). The solids content varies with the application and in the case of metallic paints ( content of component (D~) is, as a rule, somewhat lower than in the case of so-called self-colored paints (which do not contain (D)).
The coating materials according to tha invention are prepared by the usual methods of paint formulation.
The application of the coating materials according to the invention for the preparation of the base layer is effected in a known mannex, preferably by spraying using the compressed air process or by means of airless or electrostatic spraying processes; examples of othex suitable processes are knife coating, dipping and rolling. Iron and steel are the preferred substrates in 2 ~ 7 _ 9 _ this case, but other metals, for e~xample aluminum, copper, magnesium or alloys, are al~o suitable. Fur~her-more, it is also possible in principle to u~e nonmetallic substrates, such as ceramic materials, plastics and the like, provided that they withstand the curing tempera-tures.
~emperature~ from eo to 180C, preferably 120 to 150C, are generally used for curing the applied coat~ of paint, in the case of l-K system~. The curing ~ime i8 u~ually 10 to 40 minutes, preferably 15 to 30 minutes. In the case of 2-K systems the temperature~i are, as a rule, between 20 and 180C, preferably 20 and 80C, and the curing times are usually between 30 minutPs and 24 hour~.
Curing is preferably effected only after coating with the finish, it being possible to employ predrying or, pre~er-ably, the wet-on-wet proces 8 .
The layer thicknesses of the dried films are pre~erably 4 to 80, preferably lO to 40, ~m for the coatings ob-tained from the coating materials according to the invention; if a finish i~ employed, the layer thicknesses of the dried film are in this case generally lO to 100, preferably 20 to 60, ~m.
The composition of the clear finish i8 not critical, on the contrary all known non-pigmented or only transparent-ly pigmented coating agents are in principle, suitablefor this purpose. These can be conventional solvent-con-taining clear lacquers, water-dilutable clear lacquers or powder lacquers. It is preferable to use "high-solids" as clear finishes. In this connection reference ~hould be made, for example, to German Offer,legungsschriften 1,949,372 and 2,818,100 and to ~uropean Published Application 38,127 ~nd US Patent 4,5~1,533.
The examples which follow illustrate ~he invention.
lo p~ js3 3~ ~
, ~ompari~on E~ample 1 1 a~ Preparation of a commercially available metallic base paint corresponding to ~he s~ate o~ the art 60 parts of a 70 % strength solution in ~Solvesso 100 of a commercially available oil-free polye~ter resin (acid number: 10, dynamic viscoæity (source material) 5,500-7,000 mPas/20C, commexcial product: (R)Alftalat ~N 9S1~, 1 part of highly disperse silica, 222.2 parts of an 18 %
strength solution of cellulose acetc)butyrate in butyl acetate having an acetyl content of 13 %, a butyryl content of 37 % and an average molecular weight of 20,000 (commercial product CAB 381-0.1), 32.7 parts of melamine resin partially etherified with isobutanol (approx. 55 %
strength in 44:1 isobutanol/xylene, melamine:~ormaldehyde molar ratio 1:4, etherified with 3 mol of isobutanol, dyn~mic viscosity 500 mPas/20C, commercial product (~)Maprenal MF 590), 14 paxts of aluminum paste (metal content 65 %, solvent: white spirit or solvent naphtha), 6 parts of Solvesso 150, 5 parts of methoxypropyl acetate, 33 parts of a 5 ~ strength dispersion of a comme.rcially available wax (HO~CHST WACHS 371 FP~ in 30 parts of xylene and 64 parts of butyl acetate, 10.5 parts of xylene and 10.5 parts of butyl acetate were processed to give a paint. By adding ~ylene and butyl acetate mixed in a 1:1 ratio the base paint was diluted to a spraying consistency (DIN cup with 4 mm orifice as specified i~ DIN 53,211, 23C) of 15 ~econds. This resulted in a solids content of 18 % (2 g, 1 hol~x, 120C). ~he base paint was sprayed onto a commercially available automobile filler (subetrate: steel sheet) to a dry film thickness of 18 ~m. After exposure to air for 5 minutes the following clear lacquer was sprayed on.
1 b) Clear lac:quer for a two-coat metallic paint coating 28.33 parts of co~mercially available, extraneously crosslinking acrylic resin (65 % strength ~olution in 3~1 xylene/butanol, ~ynamic viscosity ~50 % strength in ;, .
. ' , .
xylene) 1140 mPas/20C, acid number 13, relative to solid resin, commercial product: ~R)Synthacryl SC 303), 24.54 parts of commercially available, ex~raneously crosslink-ing acrylic resin (75 ~ strength ~olution in Solvesso 100, dynamic viscosity 2g5 mPas/20C, acid number: lO, relative to solid resin, commercial product:
Synthacryl SC 370), 28.7 parts of mel~mine re~in partially etherified with isobutanol (approx. 55 ~
strength in 44:1 isobutanol/xylene, melami.ne:formald2hyde molar ratio 1:4, etherified with 3 mol of i~obutanol, dynamic viscosity 500 mPas/20"C, commercial product:
Maprenal NF 650), O.5 part of commercially available W
absorber ~R~Tinuvin 292 as curing component, 0.5 part of commercially available HAL stabilizer ~R~Tinuvin 900, 5.12 parts of i60butanol, 3.12 parts of an aromatic hydrocarbon mixture of boiling range 180-200DC, and 9.19 parts of an aliphatic hydrocarbon mixture of boiling range 145-200C wexe mixed. The spraying viscosity (DIN
cup with 4 mm orifice as specified in DIN 53,211, 23C) of this clear lacquer was then adjusted to 26 seconds by means o~ a hydrocarbon mixture of boiling range 150-180C, and the lacquer was applied in a dry film thick-ness of 40 ~m. Both layers were baked in one operation in 25 minutes at 140C.
Comp~ri~on Esample 2 Comparison Example la) was repeated, with the differ~nce that only 111.1 parts of an 18 % strength solution of cellulose acetobutyrate in butyl acetate were employed instead of 222.2 parts of the same cellulo~e acetobuty-rate solution. This gave a solid~ content of 27 % (2 g, 1 hour, 120C). Further processing was carried out aR in Comparison Example la), a clear 1 cquer of the ~ame composition ~s in Comparison Example lb) being spr~yed on an~ both layers being baked in an operation la~ting 25 minutes at 140C.
Example 3 Comparison Example 2 was repeated with the differences that 80 parts of the commercially available, oil-free polyester Alftalat ~N 951 in ';olvesso 100 were employed instead of 60 parts of the 70 ~ strength solution of the same resin, and that 46 parts of a thixotropic premix were employed instead of 32 . 7 parts of the 55 % strength commercially a~ailable butylated melamine resin Maprenal MF 590. This premix was prepared by introducing a cellulose acetobutyrate having a 4 % acetyl content, a 51 % butyryl content/ a hydro~yl content of 0.8 and an average molecular weight of 57,000 (commercial product CAB 500-5) in solid form into the abovementioned melamine resin solution (Maprenal MF 590) at a temperature of 80-100C and maintaining this temperature level for approx.120 minutes. A solids content of 26 % (2 g, 1 hour, 120C) was obtained. Further processing was carried out as in Comparison Example 2.
Example ~
Comparison Example 2 was repeated with the differences that only 54.6 parts of the commercially available, oil-free polyester Alftalat AN 951 were employed instead of 60 parts of the 70 ~ strength solution of the same resin in Sol~esso 100 and that 27 parts of a thixotropic premix were additionally employed. This premix was prepared by introducing the cellulose acetobutyrate according to Example 3 in solid form into the oil-f~ee polyester resin Alftalat AN 951 at a temperature of 120C and maintaining this temperature level for approx. 120 minutes. A8 a further difference from Comparison Example 2, 45 parts of a 55 ~ strength commercially available butylated melamine resin (commercial product: Maprenal MF 590) were now employed instea~ of 32.7 parts of this resin. This resulted in a solids content of 26 % (2 g, 1 hour, 120C). Further processing was carried out as in Comparison Example 2.
2 0 1 ~ :rj ~xample 5 Comparison Example 2 was repeated with the diffQrences that 51 parts of a 65 % strength solution in 3:1 xylene/
butanol of the commercially available t extraneously crosslinking acrylic resin ~dynamic viscosity (50 %
strength solution in xylene) 1140 mPas/20C, acid number 13, relative to solid resin, trade name:
Synthacryl SC 303) were employed inst~ad of 60 parts of the 70 % solution in Sol~esso 100 of the commercially available, oil-free polyester resin Alftalat ~N 951, and that 36.6 parts of a thixotropic pxemix wera additionally employed. This premix was prepared by introdu~ing the cellulose acetobutyrate according to Example 3 into the abovPmentioned acrylic resin at a temperature of 120C.
As a further difference from Comparison Example 2, 45 parts of the 55 % strength butylated melamine resin Maprenal MF 590 were employed instead of 3~.7 parts of the same resin. A solids content of 23 % (2 g, 2 hours, 120C) was obtained. Further processing was carried out as in Comparison Example 2.
~ample 6 Example 3 was repeated with the differences that 45 paxts of the butylated melamine resin Maprenal MF 590 and 26 parts of a premix made by introducing the cellulose acetobutyrate according to Example 3 into boiling toluene in the course of approx. 120 minutes, were employed instead of 46 parts of the premix described in Example 3.
A solids content of ~6 % (2 g, 1 hour, 120C~ was obtained. Further processing was carried out as in Comparison Example 2.
The properties and the behavior of the paints and paint coats obtained in Comparison Example 1 and 2 and in Examples 3 to 6 (invention~ are shown in the table below.
Assessment of the baked paint coatings was carried out visually.
5 ~ 7 ~n ~ O
a PC
~D I O
I ~
~1 IdP ~ ~ O
o U~ ~ o ~1 1 a) ~-1 0 I W~
~ I a) ~ (a P Fi I ~ h~
~1 o ,f ~ I I
~ I ~ 0 a tq I ~:n I '1 1 o D O ~1 ~
~ I , 7~
o o ~ o ~ ~ ~ ~ ~ ~
O ~ ~~ o u a~ ~ ~ O
e ~ w ~
IJ w ~ rl h h ~ .-1 1 ~ u ~ o ~ O O ~
O ~C I 1` IIJ U ~ O ~ 1 0--I o o ~ ~C
m ~ ~-~I-rl O
0 ~ 1 U~rl O ~ o ~ ~U o .4 W
O
O rl --I P~ h O ~ ~ ~ O
E~ ¢ M .¢ ~ ~1 0 , :: :
'
There has, therefore, been no lack of attempts to in-crease ths solids content or to reduce the proportion of volatile solvents. In the course of this it has been found that paints having a solids content increased in the customary manner have too high a vi6cosity, ~an only be applied with difficulty and result in paint layers having unsatisfactory technical properties in use. ~his route to the preparation o~ paints, in particular base paints, which are le~s harmful to the environment and, as a result of the higher solids content, are more product-ive and hence economical, cannot therefore be taken.
The invention therefore relates to a coating material for the preparation of coatings, in particular ~ulti-layer paint coatings composed of at least one ba~e layer and, if appropriate, at least one transparent top coat, the coating material containing film-forming resin~ (A), cellulose esters ~B), solvellts (C), preferably metallic pi~ments (D~ and, if appropriate, crosslinking sgent~ (E) and also, if appropriate, further paint addi~ives (F), wherein the cellulose ester (B) has an acetyl content of 2.0 to 30 ~ by weight, a butyryl content of 17 to 53 ~ by weight and an average molecular weight k~ of at least 25,000, this cellulose ester (B) having been introduced into the coating material in the form of a pasty, 8 ~ ~ 7 thixotropic premix.
The invention also relates ~o a process for the prepar-ation of a multi-layer coa~inS~ using this coating mater-ial and to the substrates thus l~oated.
It was surprising and not to be foreseen that, in the coating material according to the invention, the amount of cellulose ester can be reduced from the approx 40 ~
hitherto customary to about one half. This makes p~ssible an increase in the ~olids content from approx. 15 % to approx. 30 %, preferably 26 ~, and hence a considerable saving of solvent. It was al~o surprising that a paint of such a composition has a low viscosity, in spite of its high solids content; it can therefore be applied without difficulties and, in ~he case of a metallic paint, produces a fault~free metal effect. As a result of the special rheological behavior and the rapid drying, there is also no sagging on vertical suraces and no blushing~
In the case of a mul~i~layer paint coat it is also possible to overpaint without difficulties even after a few minutes dryins~ at room temperature, i.e. no in~ipient dissolution of the incipiently dried base paint takes place as a result of the finish applied later. In gener-al, ~he tLme of exposure to air after which the layer of base paint can be o~erpainted is 2 to 10 minutes, prefer-ably 3 to 6 minutes, at 15 to 30DC, preferably 20 to 25C.
The cellulose ester (B) is preferably cellulose aceto-butyrate; in addition cellulose propionate, cellulo~e butyrate and cellulose acetopropionate and al~o mixtures of the various cellulose esters are also 6uitable. The cellulose acetobutyrate which is preferably employed has an acetyl content of 2 to 5 % by weight, particularly 3 to 5 % by weis~ht, and a butyryl content of, preferably, 47 to 53 ~ by weight, especially 50 to 52 ~ by weight.
The hydroxyl c:ontent is usually 0 5 ~o 1.8 ~ by weight, preferably 0.6 to 1.0 ~ by weight. The average molecular weight Mn preferably has values between 30,000 and 60,000, especially between 54,000 and 60,000.
The amount of cellulose ester (B) in the coatin~ material is generally 0.5 to 6, pxaferably 1 to 3, % by weight, relative to the sum of (A) and (B) and also, if appropri-ate, (~) (solids content). ~rhe cellulose e~ter (B) according to the invention can also, if appropriate, be employed as a mixture with conventional cellulose e~ter~, for example those described in German Offenlegungs6chrift 1,949,372 which was mentioned initially.
In accordance with the invention the cellulose ester (B) is added to the coating material in the form of a pasty (viscous), thixotropic premix (master bakch) which preferably has a gelatinous consistency. In addition to the cellulose ester, this premix contains a diluen which essentially swells the cellulose ester only incipiently.
The boiling point (under normal pressure) of this diluent is generally at least 70~C, preferably between 70 and 250C. Examples of these diluents are aromatic or ali-phatic hydrocarbons, such as ben2ene, toluene, thevarious xylenes, higher-boiling mineral oil fractions, such as ~)Solvesso, higher alcohols having at least 4 carbon atoms, preferably 4 to 10 carbon atoms, such as n-butanol, isobutanol, pentanols, hexanols etc. or corresponding mixtures. ~he amount of cellulose ster (B) in this premix i8 usually l to 10 % by weight, preferably 2 to 6 % by weight, relative to this premix.
In a further embodiment this premix also contains, în addition, polymers or prepol~mers, especially tho~e which are in any case used in the coating material according tD
the invention. These polymers/prepolymers can be at least partly soluble in the diluent used for the premi~.
E~amples of pol~mers/prepolymers of this type are, intex alia, customary ~mino resins, such as polycondensates formed from melamine, benzoguanamine and/or ur~a with formaldehyde which are etherified, for example with monoalcohols, e~amples of suitable monoalcohols being (3 ~ ~ 7 methanol, ethanol, propanol or butanol. Methylated, propylated or butylated methylolmelamine may be men~ioned here. Further examples are polyester resins, preferably free from oil, and acrylate re~ins.
This premix is prepared by combining the cellulose ester (B) with the other constituent(s) of the mixture for 30 to 180 minutes, preferably 100 to 140 minllte~, at an elevated temperature, the :Level of the temperature under normal conditions being at least 70C, preferably between 70 and 250C.
Suitable film-foxmin~ resins (A), the average molecular weights M~ ~determined by gel permeation chromatography aga.inst a polystyrene standard) of which are usually within the range from about 500 to 50,000, preferably about 1,000 to 20,000, are the pol~mers known for this purpose which contain active groups for crosslinking, above all hydroxyl and/or amino groups. Ex2mples of these are synthetic resins (polyols) containing OH groups, such as polyether-polyols, polyacetal-polyols, polyester-amide polyols, epoxy resin polyols or reaction products thereof with CO2, phenolic resin polyols, polyurea-polyols, polyurethane-polyGls, partly saponified homopolymers and copolymers of vinyl esters, partly acetalized polyvinyl alcohols, polyester-polyols or acrylate resin polyols.
Phenolic, urea or melamine resins containing OH are also suitable in this respect. Polyols of this type, which can also be employed as a mixture, are described, for example, in German Offenlegungsschriften 2,314,513 and 3,124,784 and in European Published Applications 123,880 and 189,728. Other resins (A~ for the base paint which are suitable according to the invention are also dis-closed, for example~ in German Offenlegun~sschriften 1,949,372, ~,818,093, 2,818,100 and 3,720,984 and European Published Applications 5,428 and 80,340.
Epoxy resin polyols, polyester-polyols, polyuxethane-polyols, polyether-polyols and acrylate resin polyols are preferred.
In one embodiment of the invention these film-forming resins can be self-curing because, for example, some of the hydroxyl groups have been reacted w:ith partly masked isocyanates.
The amount of component (A) in the coating material according to the invention is generally between and 90 % by weight, preferably betwsen 5 and 30 % by weight, relative to the coating material.
Sui.table solvents (C) are, above all, (cyclo)aliphatic and/or aromatic hydrocarbons, ~uch as hexane~ heptane, cyclohexane, benzene, toluene, the various xylenes and aromatic solvents within a boiling range of approx. 150 to 180C (higher-boiling mineral oil fraction~, such as ~R~Solvesso); also halogenated hydrocarbons, ethers and glycol ethers, such as diethyl ether, 1,2-dLmetho~y-ethane, ethylene glycol dibutyl e~her, tetrahydrofuran or dioxane; ketones, such as, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like; esters, such as ethyl acetate, butyl acetate/
ethylene glycol monoethyl ether acetate and methoxypropyl acetate; N-methylpyrrolidone; monohydric or polyhydric alcohols, such as butanol, ethylene glycol monoethyl-(butyl~ ether etc~ The amount of this solvent should be such that the coating material can be handled in an optimum manner depending on the method of application chosen and that the paint films applied level out to an adequate extent. In general, amounts of 70 to 85, prefer-ably 70 to 80, % by weight, relative to the coating material, are sufficient for this.
The coating materials according to the invention contain - if appropr:iate as well as customary non-metallic (colored) pigments (in this regard see under (F) below) -metallic pi~ments (D), preferably in powder form, on their own or as a mi~ture, such as aluminum bronzes or copper bron~es, preferably aluminum powder. The amount thereof is generally 0.5 to 60, preferably 0.5 to 40, ~
:
2 ~
by weight, relative to (A).
These metallic pigments are advantageously incorporated into the coating material in the form of pigment pastes.
In addition to the metallic pigment and sol~ent, this pigment paste contains a so-c:alled grinding resin or paste resin, such as polyesters or acrylic resin~.
The grinding resin can often be equivalent to the film-forming resin (A).
Suitable crosslinking agents (E) - in the event that (A) is not self-curing - are the curing agents customary for extraneously crosslinking two-component lac~uers, for example amino resins, such as melamine/formaldehyde, benzoguanamine/formaldehyde~ ureatformaldehyde or thio-urea/formaldehyde condensates, in particular melamine/
formaldehyde condensates which have been etherified with alkanols; also phenolic resins, (masked) polyisocyanates, ~-hydroxyesters of polycarboxylic acids, poly~ hydroxy-urethanes), polyepoxide compounds, reaction products of dialkylmalona~es with aldehydes and ketones which react with the elimination of water to give unsaturated dicar-boxylic acid esters (Knoevenagel æynthesis), transesteri-fication or transamidation curing agents and also Michael addition products, for example those described in German Offenlegungsschriften 3,315,469, 3,417,441 and 3,436,345.
The crosslinking agents (E) are usually employed in amounts of 5 to 90 ~ by weight, preferably 10 to 70 % by weight, relative to the film-forming resin (~.
Exampl~s of customary paint additives (F) which can, if appropriate, be present in the coating material according to the invention are (colored) pigments and fillers and also paint auxiliaries, for example anti-settling agents, foaming agents and/or wetting agents, levelling agents, reactive thin:ners, plasticiæers, stabilizers, catalysts, rheology auxiliaries ~such as microgels or polyurea derivatives) and the like. At least some of these 20~53~87 additives can be added to the coating material aæ late as immediately before processing.
Addition to the individual components or to the whole mixture is also possible. The selection and the S proportionation of these substcmces are known to ~hose skilled in the art.
Iron oxides (iron red or iron black), lead vxides, lead silicates, titanium dioxide, z.inc oxide, ~inc sul~ide, chrome-titanium yellow, ultramarine blue, carbon black, phthalocyanine complexes, quinacridone~, halogenated thioindigo pigments, ~lavanthrone yellow, indanthrone blue, perylene red etc. and also effect pigments, such as Iriodin, should be mentioned as examples of (colored) pigments, which can have an inorganic or organic nature.
These pigments are usually employed in amounts of 0.1 to 20, preferably 0.5 to 5, % by weight, relative to component (A).
The total solids content (including the metallic pig-ments (D) and the paint additives (F)~ in the coating materials according to the invention i8 generally 10 to 30 % by weight, preferably 15 to 30 % by weight and particularly 20 to 30 ~ by weight (120C/1 hour). The solids content varies with the application and in the case of metallic paints ( content of component (D~) is, as a rule, somewhat lower than in the case of so-called self-colored paints (which do not contain (D)).
The coating materials according to tha invention are prepared by the usual methods of paint formulation.
The application of the coating materials according to the invention for the preparation of the base layer is effected in a known mannex, preferably by spraying using the compressed air process or by means of airless or electrostatic spraying processes; examples of othex suitable processes are knife coating, dipping and rolling. Iron and steel are the preferred substrates in 2 ~ 7 _ 9 _ this case, but other metals, for e~xample aluminum, copper, magnesium or alloys, are al~o suitable. Fur~her-more, it is also possible in principle to u~e nonmetallic substrates, such as ceramic materials, plastics and the like, provided that they withstand the curing tempera-tures.
~emperature~ from eo to 180C, preferably 120 to 150C, are generally used for curing the applied coat~ of paint, in the case of l-K system~. The curing ~ime i8 u~ually 10 to 40 minutes, preferably 15 to 30 minutes. In the case of 2-K systems the temperature~i are, as a rule, between 20 and 180C, preferably 20 and 80C, and the curing times are usually between 30 minutPs and 24 hour~.
Curing is preferably effected only after coating with the finish, it being possible to employ predrying or, pre~er-ably, the wet-on-wet proces 8 .
The layer thicknesses of the dried films are pre~erably 4 to 80, preferably lO to 40, ~m for the coatings ob-tained from the coating materials according to the invention; if a finish i~ employed, the layer thicknesses of the dried film are in this case generally lO to 100, preferably 20 to 60, ~m.
The composition of the clear finish i8 not critical, on the contrary all known non-pigmented or only transparent-ly pigmented coating agents are in principle, suitablefor this purpose. These can be conventional solvent-con-taining clear lacquers, water-dilutable clear lacquers or powder lacquers. It is preferable to use "high-solids" as clear finishes. In this connection reference ~hould be made, for example, to German Offer,legungsschriften 1,949,372 and 2,818,100 and to ~uropean Published Application 38,127 ~nd US Patent 4,5~1,533.
The examples which follow illustrate ~he invention.
lo p~ js3 3~ ~
, ~ompari~on E~ample 1 1 a~ Preparation of a commercially available metallic base paint corresponding to ~he s~ate o~ the art 60 parts of a 70 % strength solution in ~Solvesso 100 of a commercially available oil-free polye~ter resin (acid number: 10, dynamic viscoæity (source material) 5,500-7,000 mPas/20C, commexcial product: (R)Alftalat ~N 9S1~, 1 part of highly disperse silica, 222.2 parts of an 18 %
strength solution of cellulose acetc)butyrate in butyl acetate having an acetyl content of 13 %, a butyryl content of 37 % and an average molecular weight of 20,000 (commercial product CAB 381-0.1), 32.7 parts of melamine resin partially etherified with isobutanol (approx. 55 %
strength in 44:1 isobutanol/xylene, melamine:~ormaldehyde molar ratio 1:4, etherified with 3 mol of isobutanol, dyn~mic viscosity 500 mPas/20C, commercial product (~)Maprenal MF 590), 14 paxts of aluminum paste (metal content 65 %, solvent: white spirit or solvent naphtha), 6 parts of Solvesso 150, 5 parts of methoxypropyl acetate, 33 parts of a 5 ~ strength dispersion of a comme.rcially available wax (HO~CHST WACHS 371 FP~ in 30 parts of xylene and 64 parts of butyl acetate, 10.5 parts of xylene and 10.5 parts of butyl acetate were processed to give a paint. By adding ~ylene and butyl acetate mixed in a 1:1 ratio the base paint was diluted to a spraying consistency (DIN cup with 4 mm orifice as specified i~ DIN 53,211, 23C) of 15 ~econds. This resulted in a solids content of 18 % (2 g, 1 hol~x, 120C). ~he base paint was sprayed onto a commercially available automobile filler (subetrate: steel sheet) to a dry film thickness of 18 ~m. After exposure to air for 5 minutes the following clear lacquer was sprayed on.
1 b) Clear lac:quer for a two-coat metallic paint coating 28.33 parts of co~mercially available, extraneously crosslinking acrylic resin (65 % strength ~olution in 3~1 xylene/butanol, ~ynamic viscosity ~50 % strength in ;, .
. ' , .
xylene) 1140 mPas/20C, acid number 13, relative to solid resin, commercial product: ~R)Synthacryl SC 303), 24.54 parts of commercially available, ex~raneously crosslink-ing acrylic resin (75 ~ strength ~olution in Solvesso 100, dynamic viscosity 2g5 mPas/20C, acid number: lO, relative to solid resin, commercial product:
Synthacryl SC 370), 28.7 parts of mel~mine re~in partially etherified with isobutanol (approx. 55 ~
strength in 44:1 isobutanol/xylene, melami.ne:formald2hyde molar ratio 1:4, etherified with 3 mol of i~obutanol, dynamic viscosity 500 mPas/20"C, commercial product:
Maprenal NF 650), O.5 part of commercially available W
absorber ~R~Tinuvin 292 as curing component, 0.5 part of commercially available HAL stabilizer ~R~Tinuvin 900, 5.12 parts of i60butanol, 3.12 parts of an aromatic hydrocarbon mixture of boiling range 180-200DC, and 9.19 parts of an aliphatic hydrocarbon mixture of boiling range 145-200C wexe mixed. The spraying viscosity (DIN
cup with 4 mm orifice as specified in DIN 53,211, 23C) of this clear lacquer was then adjusted to 26 seconds by means o~ a hydrocarbon mixture of boiling range 150-180C, and the lacquer was applied in a dry film thick-ness of 40 ~m. Both layers were baked in one operation in 25 minutes at 140C.
Comp~ri~on Esample 2 Comparison Example la) was repeated, with the differ~nce that only 111.1 parts of an 18 % strength solution of cellulose acetobutyrate in butyl acetate were employed instead of 222.2 parts of the same cellulo~e acetobuty-rate solution. This gave a solid~ content of 27 % (2 g, 1 hour, 120C). Further processing was carried out aR in Comparison Example la), a clear 1 cquer of the ~ame composition ~s in Comparison Example lb) being spr~yed on an~ both layers being baked in an operation la~ting 25 minutes at 140C.
Example 3 Comparison Example 2 was repeated with the differences that 80 parts of the commercially available, oil-free polyester Alftalat ~N 951 in ';olvesso 100 were employed instead of 60 parts of the 70 ~ strength solution of the same resin, and that 46 parts of a thixotropic premix were employed instead of 32 . 7 parts of the 55 % strength commercially a~ailable butylated melamine resin Maprenal MF 590. This premix was prepared by introducing a cellulose acetobutyrate having a 4 % acetyl content, a 51 % butyryl content/ a hydro~yl content of 0.8 and an average molecular weight of 57,000 (commercial product CAB 500-5) in solid form into the abovementioned melamine resin solution (Maprenal MF 590) at a temperature of 80-100C and maintaining this temperature level for approx.120 minutes. A solids content of 26 % (2 g, 1 hour, 120C) was obtained. Further processing was carried out as in Comparison Example 2.
Example ~
Comparison Example 2 was repeated with the differences that only 54.6 parts of the commercially available, oil-free polyester Alftalat AN 951 were employed instead of 60 parts of the 70 ~ strength solution of the same resin in Sol~esso 100 and that 27 parts of a thixotropic premix were additionally employed. This premix was prepared by introducing the cellulose acetobutyrate according to Example 3 in solid form into the oil-f~ee polyester resin Alftalat AN 951 at a temperature of 120C and maintaining this temperature level for approx. 120 minutes. A8 a further difference from Comparison Example 2, 45 parts of a 55 ~ strength commercially available butylated melamine resin (commercial product: Maprenal MF 590) were now employed instea~ of 32.7 parts of this resin. This resulted in a solids content of 26 % (2 g, 1 hour, 120C). Further processing was carried out as in Comparison Example 2.
2 0 1 ~ :rj ~xample 5 Comparison Example 2 was repeated with the diffQrences that 51 parts of a 65 % strength solution in 3:1 xylene/
butanol of the commercially available t extraneously crosslinking acrylic resin ~dynamic viscosity (50 %
strength solution in xylene) 1140 mPas/20C, acid number 13, relative to solid resin, trade name:
Synthacryl SC 303) were employed inst~ad of 60 parts of the 70 % solution in Sol~esso 100 of the commercially available, oil-free polyester resin Alftalat ~N 951, and that 36.6 parts of a thixotropic pxemix wera additionally employed. This premix was prepared by introdu~ing the cellulose acetobutyrate according to Example 3 into the abovPmentioned acrylic resin at a temperature of 120C.
As a further difference from Comparison Example 2, 45 parts of the 55 % strength butylated melamine resin Maprenal MF 590 were employed instead of 3~.7 parts of the same resin. A solids content of 23 % (2 g, 2 hours, 120C) was obtained. Further processing was carried out as in Comparison Example 2.
~ample 6 Example 3 was repeated with the differences that 45 paxts of the butylated melamine resin Maprenal MF 590 and 26 parts of a premix made by introducing the cellulose acetobutyrate according to Example 3 into boiling toluene in the course of approx. 120 minutes, were employed instead of 46 parts of the premix described in Example 3.
A solids content of ~6 % (2 g, 1 hour, 120C~ was obtained. Further processing was carried out as in Comparison Example 2.
The properties and the behavior of the paints and paint coats obtained in Comparison Example 1 and 2 and in Examples 3 to 6 (invention~ are shown in the table below.
Assessment of the baked paint coatings was carried out visually.
5 ~ 7 ~n ~ O
a PC
~D I O
I ~
~1 IdP ~ ~ O
o U~ ~ o ~1 1 a) ~-1 0 I W~
~ I a) ~ (a P Fi I ~ h~
~1 o ,f ~ I I
~ I ~ 0 a tq I ~:n I '1 1 o D O ~1 ~
~ I , 7~
o o ~ o ~ ~ ~ ~ ~ ~
O ~ ~~ o u a~ ~ ~ O
e ~ w ~
IJ w ~ rl h h ~ .-1 1 ~ u ~ o ~ O O ~
O ~C I 1` IIJ U ~ O ~ 1 0--I o o ~ ~C
m ~ ~-~I-rl O
0 ~ 1 U~rl O ~ o ~ ~U o .4 W
O
O rl --I P~ h O ~ ~ ~ O
E~ ¢ M .¢ ~ ~1 0 , :: :
'
Claims (13)
1. A coating material for the preparation of coatings, in particular multi-layer paint coatings composed of at least one base layer and, if appropriate, at least one transparent cover coat, the coating material containing film-forming resins (A), cellulose esters (B), sol-vents (C), preferably metallic pigments (D) and, if appropriate, crosslinking agents (E) and also, if appropriate, further paint additives (F), wherein the cellulose ester (B) has an acetyl content of 2.0 to 30 %
by weight, a butyryl content of 17 to 53 % by weight and an average molecular weight ?n of at least 25,000, this cellulose ester (B) having been introduced into the coating material in the form of a pasty, thixotropic premix.
by weight, a butyryl content of 17 to 53 % by weight and an average molecular weight ?n of at least 25,000, this cellulose ester (B) having been introduced into the coating material in the form of a pasty, thixotropic premix.
2. A coating material as claimed in claim 1, wherein the cellulose ester (B) has an acetyl content of 2 to 5 % by-weight and a butyryl content of 47 to 53 % by weight.
3. A coating material as claimed in claim 1 and/or 2, wherein the cellulose ester (B) has an average molecular weight ?n of 30,000 to 60,000.
4. A coating material as claimed in at least one of claims 1 to 3, wherein the pasty, thixotropic premix contains, in addition to the cellulose ester (B), a diluent which incipiently swells (B).
5. A coating material as claimed in claim 4, wherein the diluent is an aromatic or aliphatic hydrocarbon or a higher alcohol.
6. A coating material as claimed in claim 4 and/or 5, wherein the thixotropic premix contains, in addition, an amino resin, a polyester resin an acrylate resin or appropriate mixtures.
7. A coating material as claimed in at least one of claims 1 to 6, wherein the amount of cellulose ester (B) is 0.5 to 6 % by weight, relative to the sum of (A), (B) and, if appropriate, (E).
8. A coating material as claimed in at least one of claims 1 to 7, wherein the film-forming resin (A) used is a polyacrylate resin containing hydroxyl groups or an oil-free polyester containing hydroxyl groups.
9. A coatinq material as claimed in at least one of claims 1 to 8, wherein the crosslinking agent (E) is a melamine resin.
10. A coating material as claimed in at least one of claims 1 to 9, wherein the solids content is 15 to 30 %
by weight.
by weight.
11. A coating material as claimed in at least one of claims 1 to 10, which contains (colored) pigments as paint additives (F).
12. A process for the preparation of multi-layer paint coatings in which a coating material which preferably Contains metallic pigments, is applied to a substrate in order to form a base layer and, after a period of ex-posure to air, a second coating material which forms a transparent top coat is applied thereto by the wet-on-wet process, which comprises employing the coating materials as claimed in at least one of claims 1 to 11 for the base layer.
13. A substrate coated with a multi-layer paint coating composed of at least one base layer, preferably contain-ing metallic pigments, and at least one transparent top coat, wherein a coating material as claimed in at least one of claims 1 to 11 has been used for the preparation of the base layer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3919028.5 | 1989-06-10 | ||
| DE3919028A DE3919028A1 (en) | 1989-06-10 | 1989-06-10 | COATING SIZE, METHOD FOR PRODUCING COATINGS AND SUBSTRATES COATED WITH IT |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2018587A1 true CA2018587A1 (en) | 1990-12-10 |
Family
ID=6382511
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002018587A Abandoned CA2018587A1 (en) | 1989-06-10 | 1990-06-08 | Coating material, process for the preparation of coatings and substrates coated therewith |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0402772A1 (en) |
| JP (1) | JPH0331382A (en) |
| KR (1) | KR910000962A (en) |
| AU (1) | AU628180B2 (en) |
| BR (1) | BR9002723A (en) |
| CA (1) | CA2018587A1 (en) |
| DE (1) | DE3919028A1 (en) |
| PT (1) | PT94324A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4133290A1 (en) * | 1991-10-08 | 1993-04-15 | Herberts Gmbh | METHOD FOR PRODUCING MULTILAYER LACQUERING USING RADICALLY AND / OR CATIONICALLY POLYMERIZABLE CLEAR VARNISHES |
| DE4426039A1 (en) * | 1994-07-22 | 1996-01-25 | Basf Lacke & Farben | Process for the production and repair of multi-layer effect coatings |
| US5849365A (en) * | 1997-02-18 | 1998-12-15 | Basf Lacke + Farben, Ag | Method for the production and repair of multicoat special-effect coating |
| US8461234B2 (en) * | 2003-03-14 | 2013-06-11 | Eastman Chemical Company | Refinish coating compositions comprising low molecular weight cellulose mixed esters |
| JP4507535B2 (en) * | 2003-09-02 | 2010-07-21 | 東亞合成株式会社 | Paint composition |
| CN110551423A (en) * | 2019-10-16 | 2019-12-10 | 天津宝丽杰涂料有限公司 | Metal coating with anti-corrosion effect |
| CN118530492B (en) * | 2024-06-13 | 2024-12-06 | 上海人民印刷八厂有限公司 | A water-resistant packaging box and its preparation process |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3411941A (en) * | 1965-03-01 | 1968-11-19 | Eastman Kodak Co | Process for coating a metallic article with thermally reflowable cellulose acetate butyrate/melamine-formaldehyde resin/alkyd or acrylic resin coating compositions |
| US3637546A (en) * | 1968-11-29 | 1972-01-25 | Du Pont | Thermosetting acrylic enamel containing cellulose acetate butyrate |
| GB2156829B (en) * | 1984-04-02 | 1987-08-19 | Kodak Ltd | Base coat compositions for wet-on-wet applicatons, and articles coated therewith |
-
1989
- 1989-06-10 DE DE3919028A patent/DE3919028A1/en not_active Withdrawn
-
1990
- 1990-06-07 EP EP90110795A patent/EP0402772A1/en not_active Withdrawn
- 1990-06-08 PT PT94324A patent/PT94324A/en not_active Application Discontinuation
- 1990-06-08 BR BR909002723A patent/BR9002723A/en unknown
- 1990-06-08 AU AU56916/90A patent/AU628180B2/en not_active Ceased
- 1990-06-08 CA CA002018587A patent/CA2018587A1/en not_active Abandoned
- 1990-06-08 JP JP2148869A patent/JPH0331382A/en active Pending
- 1990-06-09 KR KR1019900008448A patent/KR910000962A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| AU628180B2 (en) | 1992-09-10 |
| KR910000962A (en) | 1991-01-30 |
| PT94324A (en) | 1991-02-08 |
| AU5691690A (en) | 1990-12-13 |
| EP0402772A1 (en) | 1990-12-19 |
| BR9002723A (en) | 1991-08-20 |
| JPH0331382A (en) | 1991-02-12 |
| DE3919028A1 (en) | 1990-12-13 |
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