JPH07316240A - Composition for graft copolymer,its preparation and coating composition - Google Patents

Abstract

PURPOSE: To obtain an improved composition for a graft copolymer, useful for water-based coating materials by compounding a polymer which forms a main chain, a macromonomer having specified functional groups and an unsaturation-terminated oligomer.

CONSTITUTION: There is provided a composition for obtaining a graft copolymer having a molecular weight of 3,000-500,000, comprising (A) a polymerized ethylenically unsaturated monomer for forming the main chain of a graft polymer, (B) a macromonomer for bonding to the polymer chain through a single terminal, the macromonomer having a molecular weight of 500-30,000, being neutralized at least partially, being soluble or dispersible in an aqueous carrier, having a carboxylic acid or amino-functional group, and containing 10-100 wt.%, based on the weight of the macromonomer, polymerized α,β-ethylenically unsaturated monomer, and (C) an unsaturation-terminated oligomer having a substantially lower average molecular weight and a lower water solubility than component B. The amounts of components A to C are 2-98 wt.%, 98-2 wt.%, and 1-20 wt.%, respectively.

COPYRIGHT: (C)1995,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a composition for a graft copolymer and is called a self-stabilized latex.
The present invention relates to a graft copolymer having a neutralized carboxylic acid or amino functionality which stabilizes an aqueous graft copolymer dispersion in a graft portion. In particular, the present invention relates to controlling the molecular weight of graft copolymers. The present invention also relates to a method for producing such a copolymer. Furthermore, the present invention relates to a coating composition using such a graft copolymer.

The description of the present specification is based on the priority of the present application, US Patent Application No. 246,196 (1994).
(May 19, 2016), and the description of the specification of the US patent application constitutes a part of the specification by referring to the number of the US patent application. And

[0003]

BACKGROUND OF THE INVENTION Automobiles and trucks are exterior finish coated for several well-known reasons. First, such topcoats provide barrier protection against corrosion. Second, consumers prefer exterior finishes that have an attractive aesthetic finish because of their high gloss and excellent DOI.
(Image clarity) is included.

The coating composition contains one or more film-forming polymers. Acrylic polymers are typically linear polymers that, when applied, react with a crosslinker to cure. However, the use of non-linear graft copolymers has been disclosed. For example, U.S. Pat. No. 4,801,6
No. 53 [Das et al.] Describes the use of hydroxy-functional graft copolymers.
Das et al. Describe grafting by a condensation reaction between an epoxy group of a glycidyl ester contained in an acrylic polymer and a carboxyl group present in at least a part of a vinyl polymer polymerized in the presence of the acrylic polymer. There is.

Various living polymerization methods have been disclosed in the production of graft polymers in general. These have functional groups at the ends by selectively terminating at living ends (functiona).
This is to obtain a ly-ended polymer. Polymers terminated with such functional groups may subsequently be attached to other polymers as so-called macromonomer "arms" (arms) on the polymer backbone to form comb or graft copolymers. Webster
r) is "Living Polymerization Method"
251 Science 887 (February 22, 1991 issue)
["Living Polymerization M
methods, "251 SCIENCE 887
(22 February 1991), in general, a three-dimensional shape
ms) discloses a living polymerization process for making polymers.

US Pat. No. 4,680,352 (J
anowicz et al. ), U.S. Pat. No. 4,72
2,984 (Janowicz) and PCT
WO87 / 03605 discloses the use of cobalt (Co) chelate as a chain transfer agent in free radical (radical) polymerization. The last patent shows that macromonomers prepared by cobalt chain transfer can be polymerized to form graft copolymers useful in coating resins and molding resins, but such graft copolymers are highly solid. Includes finish paints and water-based or solvent-based finish paints. However, the use of such polymers is limited to applications in automotive finishes, as disclosed, for example, in US Pat. No. 5,010,140.

Water-dispersible polymers are well known and have been used to form water-based (water-based) coating compositions, pigment dispersions, adhesives and the like. A graft copolymer containing a carboxyl group and a method for producing these polymers are disclosed in JP-A-1-182304 (publication date: July 20, 1989). This publication shows a graft copolymer having a carboxyl group, and discloses hydrophilic side chains composed of acrylic acid and methacrylic acid. The publication further discloses that a tertiary alcohol-based ester unit of acrylic acid or methacrylic acid is used to form the macromonomer used to form the graft copolymer, which is then hydrolyzed onto the polymer. It teaches forming carboxylic acid groups. The method described in this publication does not form a pure graft copolymer and is detrimental to the graft copolymer, the pigment dispersion formed from the graft copolymer and the finishing coating formed from such a composition. It produces a mixture with various low molecular weight components and is not an efficient method.

EP 0363723 (BASF) describes acid functional acrylic copolymer dispersions for use in OEM clearcoats which are crosslinked with melamine formaldehyde. This acrylic copolymer is prepared in a solvent in a two-step process. In this two-step method, the hydrophilic portion (acid-functional monomer) is concentrated in one of two steps. Then, the whole copolymer is neutralized with an amine and dispersed in water. The difference with the one-stage process product is that the two-stage acrylic has a better solids / viscosity relationship. The drawback of this technique is that the hydrophilic part requires that the amount of acid-functional monomer present exceeds 60%, which may cause a problem in moisture resistance.

[0009]

It is an object of the present invention to provide improved graft copolymer compositions useful in waterborne coatings.

Another object of the invention is to provide a coating composition comprising such a graft copolymer.

Another object of the present invention is to provide a method for producing such a graft copolymer.

[0012]

SUMMARY OF THE INVENTION The present invention is directed to a graft copolymer prepared from an acrylic copolymer macromonomer, the acrylic copolymer macromonomer being present in an amount of at least 10% by weight based on its weight. Polymerizable,
Α- having either a carboxylic acid group or an amino group
It has an unsaturated monomer for β-ethylene. Such macromonomers preferably have a weight average molecular weight (MW) of 500.
May be ˜30,000. About 2 to 98% (by weight) of this macromonomer, as detailed below,
MW by copolymerizing with a blend of 98-2% of another α-β ethylenically unsaturated monomer in the presence of an oligomeric chain transfer agent.
Of 3,000 or more to form a graft copolymer. This graft copolymer can be formed by copolymerizing a main chain monomer in the presence of an aqueous dispersion of the above macromonomer. The macromonomer can be neutralized before it is dispersed in water.

By using these graft copolymers, improved water-based or water-borne coating systems are obtained. It has been found that such compositions have the advantage of providing the desired excellent coatability for automotive finishes.

That is, in order to achieve the above object,
According to the first solution of the invention, a molecular weight of 3,000 to 5
0,000 graft copolymer compositions are characterized in that they comprise the following reaction products: (a) 2-98 based on the weight of the graft copolymer.
Wt% of polymerized ethylenically unsaturated monomers to form the polymer backbone of the graft copolymer,
(B) 98-2 based on the weight of the graft copolymer
% Of macromonomer for attaching to said polymer backbone at its single end, having a molecular weight of 50
0 to 30,000 and comprising 10 to 100% polymerized α-β ethylenically unsaturated monomer having one of a carboxylic acid function or an amine function, based on the weight of the macromonomer. Macromonomer, (c) 1.0-20 wt% of one or more terminally unsaturated oligomers based on the weight of the graft copolymer, the average being substantially lower than the macromonomer of (b). A terminal unsaturated oligomer having a molecular weight and low water solubility, provided that at least a part of the carboxylic acid or amine group is neutralized, the macromonomer is soluble or dispersible in an aqueous carrier, and the graft copolymer The oligomer has the effect of stabilizing the portion of the polymer that forms the insoluble particles and limiting the molecular weight of the graft copolymer.

Here, the oligomer or the molecular weight distribution of the oligomer may have the following end groups:

[0016]

[Chemical 1]

(Where X is --CONR ₂ , --COOR,
OR ¹ , -OCOR, -OCOOR ¹ , -NRCOOR ¹
, Halo, cyano, or substituted or unsubstituted phenyl or aryl, each R independently being hydrogen, silyl,
Alternatively, it is selected from the group consisting of substituted or unsubstituted alkyl, alkyl ether, phenyl, benzyl and aryl, where the substituted is selected from the group consisting of epoxy, hydroxy, isocyanato, cyano, amino, silyl, acid, halo and acyl. means having a substitution group, R ¹ is the same as R except H, each alkyl branched or unbranched hydrocarbons and 4-12 carbon atoms having 1 to 12 carbon atoms independently, preferably Selected from 5 to 6 cyclic hydrocarbons, halo is bromo, iodo, chloro or fluoro, except when pure dimer is used when X is substituted or unsubstituted phenyl or aryl).

The oligomer or the molecular weight distribution of the oligomer may be represented by the following formula:

[0019]

[Chemical 2]

(In the formula, n is 2 to 100 on average, and X ¹
~ ^Xn is independently the above X).

The composition according to claim 2, wherein the oligomer or the molecular weight distribution of the oligomer is represented by the following formula:

[0022]

[Chemical 3]

(In the formula, n is 2 to 20 on average, and R ¹ to
R ⁿ are each independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, alkyl ether, phenyl, benzyl and aryl, the substituents of which are epoxy,
Hydroxy, isocyanato, cyano, amino, silyl,
Selected from the group consisting of acids, acid anhydrides, halogens and acyls, each alkyl being independently a branched, unbranched or cyclic hydrocarbon having 1 to 12 carbon atoms, 4 to 12 carbon atoms, preferably 5 to 6 carbon atoms. Is selected from the group consisting of cyclic hydrocarbons, halo is selected from the group consisting of bromo, iodo, chloro or fluoro, and silyl is —SiR ² (R ³ ) (R ⁴ ), where R ² , R ³ , R ⁴ are independently alkyl, phenyl, alkyl ether or phenyl ether,
Alkyl has the same meaning as above. ).

The oligomer may include alkyl methacrylate, and the alkyl may have 1 to 10 carbon atoms.

The macromonomer may comprise 10 to 40% by weight, based on the weight of the macromonomer, of polymerized ethylenically unsaturated monomers containing carboxylic acid functional groups.

The macromonomer may further comprise 5-30% by weight, based on the weight of the macromonomer, of polymerized, ethylenically unsaturated monomers containing hydroxyl functional groups.

The polymer backbone further comprises polymerized ethylenically unsaturated monomers, the monomers being predominantly acrylates and / or styrenes, the acrylates and / or styrenes being alkyl acrylates, cyclic acrylates, aryls. An ethylenically unsaturated monomer selected from the group consisting of acrylates, styrenes, alkyl styrenes and mixtures thereof, and containing a carboxylic acid functional group, comprising a monomer selected from the group consisting of carboxylic alkyl acrylates, The carbon number of the alkyl group, the alicyclic group and the aryl group may be 1 to 12, and the macromonomer may be mainly methacrylate as described above.

The composition may be an aqueous dispersion (20 to 100% of water) of the graft copolymer.

A coating composition according to a second solution of the invention is characterized in that it comprises the graft copolymer according to claim 1.

Here, the coating composition is 2 to 50% by weight based on the weight of the binder, and reacts with the graft copolymer when the composition is cured to crosslink. Cross-linking agent and 4 based on the weight of the composition
A water-based carrier of 0 to 90% by weight, which may further include a carrier containing 20 to 100% of water.

The coating composition may contain additional curable linear or branched film-forming polymers or binder materials in various proportions.

The composition may comprise a linear or branched hydroxyl functional acrylic, polyester or polyurethane copolymer.

The binder material may contain a relatively small amount of, for example, a thickener (thickener), a fixing agent and the like.

Molecular weight 3, according to the third solution of the invention
The method for preparing a graft copolymer of 000 to 500,000 is characterized in that the following components are simultaneously reacted in an aqueous solvent: (a) 2 to 98 based on the weight of the graft copolymer.
Wt% of polymerized ethylenically unsaturated monomers to form the polymer backbone of the graft copolymer,
(B) 98-2 based on the weight of the graft copolymer
% Of macromonomer for attaching to said polymer backbone at its single end, having a molecular weight of 50
0 to 30,000 and comprising 10 to 100% polymerized α-β ethylenically unsaturated monomer having one of a carboxylic acid function or an amine function, based on the weight of the macromonomer. Macromonomer, (c) 1.0-20 wt% of one or more terminally unsaturated oligomers based on the weight of the graft copolymer, the average being substantially lower than the macromonomer of (b). A terminal unsaturated oligomer having a molecular weight and low water solubility, provided that at least a part of the carboxylic acid or amine group is neutralized, the macromonomer is soluble or dispersible in an aqueous carrier, and the graft copolymer The oligomer has the effect of stabilizing the portion of the polymer that forms the insoluble particles and limiting the molecular weight of the graft copolymer.

[0035]

The present invention offers several significant advantages. First, the graft copolymer in which acid groups or amine groups are concentrated in one segment is less required to be a stable dispersion of these functional groups, and hardly leaves moisture-sensitive groups when used in a coating material.

Second, standard emulsions are stabilized by surfactants, which remain as moisture sensitive residues in the film and migrate to the coating interface to form a weak boundary layer. This will result in weakening of adhesion and delamination. The surfactant stabilizes the bubbles formed by the air trapped during spraying and pinhole formation occurs. The graft copolymers of the present invention can also be used in compositions having lower amounts of surfactant or no surfactant at all.

Third, standard emulsions in which water is a non-solvent require a significant amount of solvent in order for flocculation (film formation) to occur after being applied to the surface.

Therefore, the VOC (volatile organic compound content) becomes high. In the present invention, the hydrophilic macromonomer on the surface of the self-stabilizing latex is plasticized by water, so that film formation occurs with little solvent or without solvent, and the coating composition can be formulated with a much lower VOC. it can. These and other advantages of the invention can be better understood with reference to the following detailed description.

Disclosed herein are water-soluble or water-dispersible graft acrylic copolymers. It is formed by the free radical initiated copolymerization of 2-98% (by weight) α-β unsaturated monomers in the presence of acrylic macromonomers. This acrylic macromonomer has an ionic character and has a number average molecular weight (MN) of 500-
It is 30,000 and contains 10% or more of acid- or amino-functional α-β unsaturated monomer. After neutralizing the carboxyl or amino groups to at least part with carboxyl groups, for example with amines, these acrylic resins form stable aqueous solutions or dispersions.

These graft copolymers may be used alone or in aggregate (aggregat) in dispersions or coating compositions.
The particles are formed in e). The macromonomer is relatively hydrophilic and therefore soluble or dispersible in the aqueous carrier and the polymer backbone (to which the macromonomer is attached) is relatively insoluble in water. Such particles may or may not be crosslinked, for example with diacrylate monomer units, and preferably have an average particle size of 50 to 1,000.
Nanometer (nm), preferably 100-250 nm.

The molecular weight of the self-stabilizing latex is controlled during polymerization using the oligomer chain transfer technique described below.
This involves the use of very low molecular weight oligomers with terminal vinyl groups as radical chain transfer agents in polymerizing the desired monomers with high molecular weight macromonomers (emulsion stabilizers).

The oligomer chain transfer agent generally has a molecular weight distribution with a very low degree of polymerization, eg DP = 2-8. These low molecular weight macromonomers differ from the macromonomers used to stabilize emulsion particles in the following ways. That is, (1) they consist of ones whose average molecular weight is lower than that of the stabilizer macromonomer itself,
(2) The oligomeric macromonomers provide emulsion stability, whereas macromonomer stabilizers do not provide this at all or to a substantially lesser extent, and (3) they typically Has little or no functional group that imparts water solubility to the oligomer.

For example, the average composition of methyl methacrylate 60% and methacrylic acid 40% and the number average molecular weight 1,200.
Stabilizing macromonomer with methyl methacrylate 1
It could be used with an oligomeric chain transfer agent consisting of 00% and having a Mn molecular weight equal to 315. The neutralized 60/40 macromonomer becomes the grafted emulsion stabilizer. This oligomer cannot neutralize, but will not be able to act as an emulsion stabilizer and can form stable low molecular weight self-stabilizing emulsions only when used with 60/40 macromonomers.

The chain transfer process, by definition, does not change the dynamic chain length that halts the growth of radical chains. The result is that from one initiating radical, several
00 polymer chains will be produced. The initiating radicals from the polymerization initiators may be derived from any conventional class of initiators such as azos, peroxides, peroxyesters or similar classes of thermal initiators as well as redox and photoinitiators.

The oligomeric chain transfer agent, like other conventional chain transfer agents, is incorporated into the polymer during the polymerization process. One advantage is that the oligomer composition does not introduce moieties that can degrade the properties of the final copolymer. In contrast, the use of conventional sulfur-containing chain transfer agents produces polymers containing groups that are less durable than the polymer being synthesized. They often leave a malodor on the resin. Some cobalt chain transfer agents are active in polymerization using water as long as the bulk of the monomer is methacrylate. Cobalt chain transfer agents may not be very effective if the self-stabilizing latex requires the use of acrylate and styrene monomers in the backbone. Cobalt catalysts also have the drawback of not working well with hydroxyl and / or carboxyl containing monomers. This is a factor that oligomer chain transfer agents do not have.

As mentioned above, one important aspect of the use of oligomeric chain transfer agents for molecular weight control is that the oligomers are as particle stable as the stabilizer macromonomers in making self-stabilizing latices. It is not to contribute. Since the oligomer is hydrophobic, it contributes to the hydrophobic part of the polymer either as an end group by chain transfer or as a short graft by copolymerization.

Stabilizer Macromonomers are themselves chain transfer agents, as defined by the mechanism of addition-elimination chain transfer agents. It can be observed that increasing the number of moles of stabilizer macromonomer in the self-stabilizing latex composition alone limits the reduction in molecular weight. Oligomer chain transfer agents offer a new way to increase the number of moles of macromonomers with terminal vinyl groups in the process due to their low molecular weight, thus increasing the concentration of molecular weight regulators and increasing the hydrophobic-hydrophilic character in the polymer composition. Has little effect on sexual balance.

Oligomer uptake and β cleavage (chain transfer)
The competition between and defines the relative activity of the oligomeric chain transfer agents and is greatly regulated by three factors.
That is, (1) temperature-the higher the polymerization temperature, the more chain transfer. (2) Main chain monomer composition-Acrylate and styrene provide a competitive mechanism for chain transfer and uptake, whereas methacrylate only undergoes chain transfer. (3) Concentration of Oligomer to Monomer in Reactor-The higher the relative molar concentration of oligomer to (meth) acrylate and / or styrene monomer in the reactor during polymerization, the greater the molecular weight reduction.

Oligomer chain transfer agents reduce variables that limit the usefulness of commercially available chain transfer agents or conventional techniques for controlling molecular weight. It works with a wide range of monomers and initiator types without adversely affecting other important polymer properties. For example, it provides the means to incorporate into the polymer acceptable monomer units that are generally considered by those skilled in the art to have a neutral or positive effect on artificial and natural weathering. The ability to adjust the molecular weight of the self-stabilizing latex provides additional variables for particle aggregation during film formation in addition to other conventional variables such as cosolvent, particle size, glass transition temperature and temperature of the polymer. The graft copolymer of the present invention is useful in coating compositions. Such compositions are preferably about 20-98 based on the weight of the binder.
%, Preferably 50-90% of the specified graft polymer. (In general, all polymeric and oligomeric components of a coating composition are conventionally referred to as "binders" or "binder solids" and are dissolved, emulsified or otherwise dispersed in an aqueous liquid carrier. It contains all the normally solid polymer components of the material. Generally, chemical additives such as catalysts, pigments or stabilizers are not considered to be part of the binder solids. No more than about 10% by weight of the composition.) The coating composition according to one aspect of the invention is suitably about 10-60% by weight, more typically 50-70%.
% Binder, and about 40-90%, more typically 50-30% aqueous carrier.

The graft copolymer itself is about 2-98% by weight, preferably 5-40% by weight, most preferably 15-.
About 98 corresponding to 40% by weight macromonomer arm
~ 2, preferably 60-95% by weight, most preferably 6
0 to 85% by weight of main chain polymer. The weight average molecular weight of the graft copolymer is about 3,000 or more, preferably 20,000 to 500,000, and most preferably 20,000 to 300,000. The side chains of the graft copolymer are formed from relatively water-soluble macromonomers, which have a weight average molecular weight of about 50.
0 to 30,000, preferably 2,000 to 10,000
0, about 10 to 1 based on the weight of macromonomer
It contains 00% by weight, preferably 15-40% by weight of polymerized ethylenically unsaturated acid or amino monomer.
These monomers are then at least partially neutralized. These side chains are relatively hydrophobic,
The graft polymer is kept well dispersed in the resulting coating composition.

Although the main chain of the graft copolymer is more hydrophobic than the side chains, it may contain a polymerized ethylenically unsaturated acid or amine monomer or a salt thereof. The backbone may contain polymerized monomers, preferably selected from the group consisting of acrylates or styrene, but may also contain up to 50% of alkyl methacrylate. Also, 50% by weight or less of a polymerized ethylenically unsaturated non-hydrophobic monomer based on the weight of the graft copolymer, which may have a functional group in addition to an amino group or an acid group, is added. It may be contained. Examples of such monomers are hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylamide, nitrophenol acrylate, nitrophenol methacrylate, phthalimidomethyl acrylate and phthalimidomethacrylate. Other vinyl monomers can be introduced into the backbone. For example, ethylenically unsaturated sulfonic acid, sulfinic acid, phosphoric acid or phosphonic acid and esters thereof, such as styrene sulfonic acid, acrylamidomethylpropane sulfonic acid, vinylphosphonic acid and esters thereof.

In one embodiment, the water-borne acrylic graft copolymer comprises 0 to 60 parts by weight, preferably 10 to 40 parts by weight of a hydroxy-functional acrylic monomer, such as 2-hydroxyethyl acrylate.
-Hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-
Contains hydroxybutyl methacrylate. All or most of these may be present in the side chain,
In addition, it may act as a crosslinking site.

As indicated previously, the graft polymer comprises macromonomer side chains attached to the polymer backbone. Each macromonomer ideally contains a single ethylenically unsaturated group that is polymerized into the backbone of the graft copolymer and is typically methacrylic acid, its esters, nitriles, amides or It contains polymerized monomers of a mixture of these monomers.

The ethylenically unsaturated carboxylic acid or amino-functional monomer is 10% by weight of the weight of the macromonomer.
Although used in the above amounts, the carboxylic acid monomer preferably includes methacrylic acid, acrylic acid, itaconic acid, maleic acid (or maleic anhydride that hydrolyzes to maleic acid after polymerization), or a mixture thereof. You can leave. Suitable amino-functional monomers include t-butylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. or mixtures thereof. The acids or amines mentioned above can also be used in the backbone of the graft copolymer, but usually in lesser weight than that used in the macromonomer arms to maintain the water insolubility of the backbone. However, in this case, it is preferable that both the main chain and the macromonomer arm are composed of the same type of monomer, either an acid monomer or an amino monomer. In addition to the minimum amount of acid or amino-functional monomer, up to 90% by weight of other polymerized ethylenically unsaturated monomers based on the weight of macromonomer may be present in the macromonomer. For example, but not limited to, acrylic or methacrylic acid esters of linear or branched monoalcohols having 1 to 20 carbon atoms can be used. Most of these monomers, ie, preferably 60-80% by weight, based on the weight of macromonomer,
Must be methacrylate. For example, an alkyl methacrylate having an alkyl group having 1 to 12 carbon atoms such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, 2-ethyl methacrylate, nonyl methacrylate, lauryl methacrylate, etc. Can be used. Alicyclic methacrylates such as trimethylcyclohexyl, methacrylate, t-butylcyclohexyl methacrylate, isobornyl methacrylate, 2-ethylhexyl methacrylate can be used. Aryl methacrylates such as benzyl methacrylate can also be used.

The ethylenically unsaturated monomer containing a hydroxy functional group has an alkyl moiety having 1 to 12 carbon atoms.
Are hydroxyalkyl acrylates and hydroxyalkyl methacrylates. Suitable monomers include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyisopropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate,
There are hydroxyisopropylmethacrylate, hydroxybutylmethacrylate, etc. and mixtures thereof. Reactive functional groups can also be obtained from monomer precursors, such as epoxy groups on the glycidyl methacrylate unit of the polymer. Such epoxy groups can be converted to hydroxyl groups with water or a small amount of acid in post-polymerization reactions, or to hydroxylamines with ammonia and / or primary amines.

Other suitable olefinically unsaturated comonomers include acrylamide and methacrylamide and derivatives as alkoxymethyl (meth) acrylamide monomers such as methacrylamide, N-isobutoxymethylmethacrylamide, and N-methylolmethacrylamide. , Itaconic anhydride and maleic anhydride and their half-esters and diesters, vinyl aromatic hydrocarbons such as styrene and vinyltoluene, polyethylene glycol monoacrylates and monomethacrylates, amino-functional (meth) acrylates such as diethylaminoethyl methacrylate and t-. Butylaminoethyl methacrylate, glycidyl functional (meth) acrylates such as glycidyl methacrylate.

Other functional monomers include acrylonitrile, acrolein, allyl methacrylate, acetoacetoxyethyl methacrylate, methyl acrylamido glycolate methyl ether, ethylene urea ethyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, trialkoxysilylpropyl. There are reaction products of methacrylates, monoepoxy esters or monoepoxy ethers with α-β unsaturated acids, and reaction products of glycidyl (meth) acrylates with monofunctional acids having up to 22 carbon atoms.

The above-mentioned monomers can also be used in the main chain of the graft copolymer.

Graft copolymers can be prepared by polymerizing ethylenically unsaturated monomers in the presence of macromonomers having terminal ethylenic unsaturation for grafting. The obtained graft copolymer can be regarded as consisting of a main chain in which a plurality of macromonomer arms are bonded. In the composition of the present invention, both the macromonomer arm and the main chain may have a reactive functional group capable of reacting with the crosslinkable compound or polymer. It is also optional to choose to have only on the monomer. Macromonomers designated as having carboxylic or amine functionality may have some of them having no carboxylic or amine functionality, or may be part of a mixture of macromonomers with varying amounts of carboxylic or amine functionality. May be It is also understood that there is usually a normal distribution of functionalities in the preparation of any macromonomer.

To ensure that the resulting macromonomer has only one terminal ethylenically unsaturated group which will polymerize with the backbone to form a graft copolymer, the macromonomer will be treated with a catalytic chain transfer agent. To prepare. Typically, the first step in the process for making this macromonomer is to blend the monomer with an inert organic solvent miscible or dispersible with water and cobalt or other chain transfer agent, and usually heated to the reflux temperature of the reaction mixture. To do. In a subsequent step, additional monomer, chain transfer agent and conventional polymerization catalyst are added and the polymerization is continued until the desired molecular weight macromonomer is formed.

The term "macromonomer" is used herein to refer to a polymer of limited chain length or molecular weight having an olefinic moiety at such end. The macromonomer has from about 10 to about 300 monomer units linked to end groups, which units are independently selected from the monomer units described below. The number average molecular weight is about 1,000 to 50,000, preferably 1,0.
It can range from 00 to 10,000.

The concentration of the macromonomer having a vinyl group at its end is about 80 mol% or more. Preferably the concentration is about 8
5 mol% or more, more preferably about 90 mol% or more, most preferably about 95 mol% or more, all concentrations and concentration ranges are in between, and maximum is about 100 mol%
Up to is intended.

The macromonomer can be prepared with a cobalt chain transfer agent such as diakobis (borodifluorodiphenyl-glyoxymate) cobaltate (II). Macromonomers are formed by a process that uses oligomers having relatively low molecular weight ω-unsaturation as free-radical chain transfer agents, which are themselves macromonomers of relatively limited degree of polymerization or chain length. be able to. These oligomers can themselves be made using metal chelates or other suitable chain transfer agent catalysts. However, although less preferred, ω-unsaturated oligomers with two or more monomer units could be prepared by known or conventional organic synthesis without polymerization. Thus, the term "oligomer" or "oligomeric" is used herein to refer to a compound necessarily prepared by polymerization.

The oligomeric chain transfer agent used in the present invention may be a pure compound or a polydisperse mixture of compounds.
These materials are effective alone or as a blend when used as chain transfer agents for virtually any radical polymerization.

Preferably, the chain transfer agent is used as a polydisperse mixture, the mixture having a very low degree of polymerization, ie DP = 2-100, preferably 2-20, most preferably 2-7. Have dispersion.

Important oligomeric chain transfer agents as well as polymers or macromonomers produced thereby are those having the following end groups:

[0067]

[Chemical 4]

(In the formula, X is -CONR ₂ , -COOR,
OR ¹ , -OCOR, -OCOOR ¹ , -NRCOOR ¹
, Halo, cyano, or substituted or unsubstituted phenyl or aryl, each R independently being hydrogen, silyl,
Alternatively, it is selected from the group consisting of substituted or unsubstituted alkyl, alkyl ether, phenyl, benzyl and aryl, where the substituted is epoxy, hydroxy, isocyanato, cyano, amino, silyl, acid (--COO
H), having a substituent selected from the group consisting of halo and acyl, R ¹ is the same as R except H, and each alkyl independently has 1 to 12 carbon atoms, preferably 1 carbon atoms.
~ 6, most preferably 1 to 4 branched or unbranched hydrocarbons and 4 to 12 carbon atoms, preferably 4 to 6 cyclic hydrocarbons, halo or halogen being bromo, iodo, chloro or fluoro, preferably Chloro and fluoro, silyl is —SiR ² (R ³ ) (R ⁴ ), where R ² , R ³ and R ⁴ are independently alkyl, phenyl, alkyl ether or phenyl ether, preferably Two or more of R ² , R ³ and R ⁴ are hydrolyzable groups, more preferably 2 of them.
Is an alkyl ether, and alkyl has the same meaning as above, preferably methyl or ethyl. Organosilanes such as Si (R
² ) ₂ —O—Si (R ³ ) ₂ R ⁴ (provided that R ² , R ³ ,
R ⁴ is independently an alkyl group). See US Pat. No. 4,518,726 for examples of silyl groups in general.

A preferred class of oligomeric chain transfer agents for use in the present invention is where X is -CONR in the above structure.
₂ , -COOR, unsubstituted or substituted phenyl, aryl, halo, or cyano, and R is an oligomer having the same meaning as described above.

A further preferred class of oligomeric chain transfer agents for use in the present invention is that in the above structure X is --COOR or phenyl, R is hydrogen, alkyl or unsubstituted or substituted with epoxy, hydroxyl or alkoxysilyl. It is an oligomer that is phenyl.

The oligomers used in the present invention should be distinguished from conventional oligomers having end groups of the formula

[0072]

[Chemical 5]

Preferably, the oligomers used in the present invention as well as the polymers produced thereby are characterized by the following end groups:

[0074]

[Chemical 6]

In the formula, X ¹ and X ² are independently (may be the same or different) the above X.

The general formula for suitable oligomers used in the present invention is as follows: However, n = 2 to 100 (average).

[0077]

[Chemical 7]

(In the formula, X ^{1 to} X ⁿ are independently the above X, and n is 2 to 100 on average, preferably 2 to 20).

For example, the general formula of the methacrylate oligomeric chain transfer agent is as follows.

[0080]

[Chemical 8]

(In the formula, R ^{1 to} R ⁿ each independently has the same meaning (may be the same or different), and n has an average of 2 to 20, preferably 2 to 7).

As a more specific example, a methyl methacrylate trimer (n = 3, R = -CH ₃ ) has the following formula.

[0083]

[Chemical 9]

As described above, the dimer,
Trimers, tetramers, tetramers, etc. or mixtures thereof are preferably used in the present invention.
Mixtures of different molecular weights are probably easier to prepare for large scale preparation. It is also possible to prepare a wide range of molecular weight oligomers and distill them to obtain purer or purer oligomers such as tetramers. The oligomer need not be in a particular form. The oligomer may be mixed as a liquid or solid in a solvent or mixed with the monomer, stored in bulk and added.

Many of the oligomers that can be used in the method of the present invention are known and are disclosed, for example, in EP-A-0261942 (Janowicz). Alpha methyl styrene dimer (the same compound as 2,4-diphenyl-4-methyl-1-pentene) is known as a chain transfer agent. However,
Chain transfer agents having such phenyl or aryl groups may be less preferred due to the nature of the resulting polymer due to the presence of aromatic end groups derived from the chain transfer agent. It may be preferable to exclude or reduce the amount of dimeric oligomers (n = 2 in the above formula). That is because such dimers may be somewhat less reactive than other oligomeric chain transfer agents.

According to the invention, suitable oligomeric chain transfer agents are monomeric dimers, trimers, tetramers and higher oligomers and mixtures thereof. Thus, branched or unbranched or cyclic alkyl or aromatic methacrylates such as methyl, ethyl, propyl, butyl, 2-ethylhexyl and / or decyl methacrylate, cyclohexyl, phenyl or benzyl methacrylate, functional alkyls or aromatics. Group methacrylates such as glycidyl methacrylate, hydroxyethyl or hydroxypropyl methacrylate, methacrylic acid, methacrylonitrile, methacrylamide, 2-isocyanatoethyl methacrylate, dimethylaminoethyl methacrylate,
N, N-Dimethylamino-3-propylmethacrylamide, t-butylaminoethylmethacrylate, and silanes such as methacryloxypropyltrimethoxysilane, or mixtures of the above, as well as various others can be used. Hetero-oligomers are suitable, for example the reaction product of methyl methacrylate and methacrylonitrile. These oligomers are most easily made with metal chelate catalyzed chain transfer agents, such as cobalt chelates, as described below. However, they could be made in another way.

The oligomeric chain transfer agent of the present invention is mainly used in the formation of the graft copolymer of the present invention, the macromonomer used to form the graft copolymer and / or the graft copolymer. It can be used to control the molecular weight during chain polymerization. The chain transfer agent can be used in an effective amount of only a few weight percent (%) of the reactants. A suitable amount range of the oligomeric chain transfer agent is 0.01% to 80% by weight, preferably about 0.1% to 40% by weight, most preferably 1 to 10% by weight based on the weight of the monomer reactant. % By weight.

Radical polymerization of unsaturated monomers, some of which carry acid functional groups for stabilization, is well known to those skilled in the art, as are suspensions, emulsions or solutions in aqueous or organic media. You can go inside.

The oligomeric chain transfer agents used in this invention are typically prepared by standard solution polymerization techniques, but by emulsion (suspension) or suspension (bulk) polymerization methods. May be. Preferably, a metal chelate chain transfer agent catalyst is used in the preparation method. (In effect, one chain transfer agent is used to make another chain transfer agent). Such a method is disclosed in US Pat. No. 4,680,352 (Jan).
owicz et al. ), U.S. Pat. No. 4,694,
054 (Janowicz), WO87 / 360
5 (International Publication June 18, 1987).

When a cobalt chelate is used to prepare the present oligomers, it is convenient to remove the cobalt and color from the reaction product by using activated carbon after precipitation with a solvent. For example, addition of ethyl acetate (Rhone-Poulin AR grade, 99.5%, 0.005% acetic acid) in various proportions causes cobalt to substantially precipitate as a dark brown solid in the final solution. It was found that the color decreased. Other precipitation solvents include acetone and water mixtures and acetonitrile and water mixtures. The color may be further removed by conventional techniques. For example, simple treatment with activated carbon for about 15 minutes may be followed by filtration through a short column packed with Celite [CELITE® 545] filter aid.

For large scale production, continuous (CSTR) production of oligomers may be more economical.

In general, to obtain some of the relatively low molecular weight oligomeric chain transfer agents of this invention, the metal chelate chain transfer agents used in the prior art to obtain relatively high molecular weight macromonomers may be used. Large amounts of metal chelate chain transfer agents could be used. In other words, essentially the same conventional methods used to make low molecular weight macromonomers can be used to make the relatively low molecular weight oligomeric chain transfer agents of the present invention, such as dimers and trimers. Initiators that produce sufficiently mild, carbon-centered radicals that do not destroy the metal chelate chain transfer agent are also typically used to prepare oligomeric chain transfer agents. Suitable initiators are the azo compounds as described below.

As will be apparent to those skilled in the art, these oligomers could be prepared in situ from the appropriate reactants. However, it is preferable to make them separately and add them to the polymerization reaction mixture.

In the macromonomer polymerization method of the present invention, the macromonomer (a polymer or copolymer having an unsaturated terminal) is produced by using the above-mentioned oligomeric chain transfer agent, and the method is preferably 20 ° C. To 200 ° C, preferably 40 to 160 ° C, more preferably 50 to 145
It is performed at ℃.

Any radical source or class of known polymerization initiators can be used, so long as the initiator has the required solubility in the selected solvent or monomer mixture and has a suitable half-life at the polymerization temperature. Are suitable. The polymerization initiator is a redox, which is thermally or photochemically induced,
It may be, for example, azo, peroxide, peroxyester or persulfate. Preferably, the initiator has a half-life at polymerization temperature of about 1 minute to about 1 hour. Some suitable initiators include ammonium persulfate, azocumene, 2,2'-azobis (2-methyl) butanenitrile, 4,4'-azobis (4-cyanovaleric acid), and 2- (t-butylazo). )
-2-Cyanopropane is mentioned. Other non-azo initiators having the required solubility and suitable half-life may be used. The macromonomer polymerization method may be a batch, semi-batch, continuous or feed method. When operated in batch mode, the reactor is typically charged with oligomeric chain transfer agent and monomer or medium and monomer. The mixture is then charged with the desired amount of initiator, typically M /
Add so that the I (monomer / initiator) ratio is 10/200. Typically, the oligomeric chain transfer agent catalyst will have a catalyst / initiator or C / I ratio of 0.10 to 2
It is added in an amount within the range of 0. The mixture is heated for the required time, usually 1.5 hours to 10 hours. In the batch process, the reaction may be carried out under pressure to avoid reflux of the monomer and it can be seen that the medium absorbs the heat of reaction.

When the macromonomer polymerization is carried out in a feed system, the reaction can typically be carried out as follows. The reactor is charged with a medium, typically an organic solvent.
Charge monomers and oligomers in separate vessels. Further, the initiator and the medium are charged in another container. While the medium in the reactor is being heated and stirred, respective solutions of the monomer, the oligomeric chain transfer agent and the initiator are introduced by, for example, a syringe pump or other pump device. The feed rate depends on the amount of solution as seed. When the feed is complete, continue heating for an additional 30 minutes. Alternatively, the reactor may be initially charged with all of the oligomeric chain transfer agent along with the medium and the monomer and initiator solution added over time.

In any type of method, the macromonomer product may be isolated by stripping the medium and unreacted monomer or by precipitation with a non-solvent. Alternatively, the macromonomer solution may be used as is if it is suitable for the application.

As mentioned above, the polymerization can be carried out either in the absence or in the presence of a polymerization medium. Many conventional organic solvents are suitable as polymerization media. These include aromatic hydrocarbons such as benzene, toluene and xylene, ethers such as tetrahydrofuran, diethyl ether and commonly available ethylene glycol and polyethylene glycol monoalkyl and dialkyl ethers (including cellosolve and carbitol), alkyls of organic acids. Esters and mixed esters-
Included are ethers such as monoalkyl ether-monoalkanoate esters of ethylene glycol. Furthermore, ketones such as acetone, butanone, pentanone and hexanone are suitable, as are alcohols such as methanol, ethanol, propanol and butanol. It may be advantageous to use a mixture of two or more solvents. Certain solvents may be preferred for environmental or toxicological reasons.

A significant advantage of this method of preparing vinyl-terminated macromonomers is that a wide range of monomers can be polymerized without adversely affecting the desired molecular weight of the macromonomer product. As mentioned above, typical methods of preparing vinyl-terminated macromonomers suffer from sensitivity to monomers containing active protons. One example is cobalt porphyrin and dioxime catalysts. U.S. Pat. No. 4,680,352 and subsequent Janowicz et al. The patent shows a typical example. Although such cobalt catalysts are widely used to prepare vinyl-terminated macromonomers, they have the disadvantage of not working well with low levels of hydroxyl and / or carboxyl containing monomers. Also, high levels of these catalysts can result in unacceptable colors in the resin. Generally, cobalt catalysts are not efficient when used with acrylate monomers. After the macromonomer is formed as described above, the solution can be used "as is". Alternatively, the solvent is optionally stripped and the backbone monomer is added to the macromonomer along with additional solvent and polymerization catalyst.

According to the present invention, the above-mentioned oligomer chain transfer agent is used to control the molecular weight when forming the graft copolymer.

Azo-based catalysts (0.5 to 5% by weight of monomer) can be used as well as other suitable catalysts such as peroxides and hydroperoxides.
Typical examples of such catalysts include di-t-butyl peroxide, dicumyl peroxide, t-amyl peroxide, cumene hydroperoxide, di (n-).
Propyl) peroxydicarbonate, peresters such as amyl peroxyacetate and the like. Polymerization is usually continued at the reflux temperature of the reaction mixture until a graft copolymer of the desired molecular weight is formed.

Organic solvents are used to form macromonomers or graft copolymers. These organic solvents include, for example, aromatic compounds, aliphatic compounds, ketones (eg methyl ethyl ketone, isobutyl ketone, ethyl amyl ketone,
Acetone), alcohol (eg methanol, ethanol, n-butanol, isopropanol), ester (eg ethyl acetate), glycol (eg ethylene glycol, propylene glycol), ether (eg:
Tetrahydrofuran, ethylene glycol monobutyl ether, etc.), and water-miscible solvents with water and mixtures thereof, as described above.

As already mentioned, first the macromonomer in the solvent is copolymerized with the remaining monomer mixture to form a graft copolymer. Next, the graft polymer is synthesized by neutralizing and dispersing in water.

Inorganic bases suitable as neutralizing agents for the acid groups include ammonium hydroxide, sodium hydroxide, and potassium hydroxide. In addition, as typical amines that can be used as a neutralizing agent, aminomethyl propanol, aminoethyl propanol, dimethyl ethanol amine, triethyl amine, dimethyl ethanol amine,
Dimethylaminomethyl propanol, aminomethyl propanol and the like are included. Furthermore, one of the suitable amines is aminomethyl propanol. on the other hand,
A suitable inorganic base is ammonium hydroxide.

When an amine group is used instead of the acid group, suitable neutralizing agents for the amine group include organic or inorganic acids (eg acetic acid, formic acid, lactic acid, hydrochloric acid, sulfuric acid, etc.).

The conversion of the graft polymer into an aqueous dispersion is carried out by mixing the graft polymer with a suitable neutralizing agent and diluting with water, or by adding the polymerized graft copolymer solution to an aqueous solution containing the neutralizing agent. It is done by slowly adding and stirring. The degree of neutralization of the dispersion is 10 to 150%, preferably 80 to 105% of the total amount of reactive groups present. Thus, the final pH of the dispersion is about 4-10, preferably 7-10 for anionic and 4-7 for cationic. Furthermore, anionic, cationic, or nonionic surfactants can be used. However, it is desirable not to use a nonionic surfactant because it may impair the wet resistance described below. As mentioned above, it is one of the excellent advantages of the present invention that there is no need to use a surfactant.

However, preferably the macromonomer is dispersed or neutralized and dissolved in water to form the graft copolymer directly in water. In the graft copolymer, the remainder of the monomer mixture (for the main chain) is mixed with a macromonomer solution or an aqueous dispersion (for the comb or graft of the graft copolymer or tooth) in the presence of the oligomeric chain transfer agent. Is formed by copolymerizing. The advantage of this method is that less cosolvent is used throughout the process and solvent stripping is eliminated. Another advantage is that a graft polymer having a higher molecular weight than that obtained by solvent polymerization can be obtained. It can be used as a mixture of macromonomers having an appropriate compatibility as long as it shows all or either of cationic or anionic properties in water.

Water-soluble free radical initiators such as peroxides, ammonium persulfate, redox initiators (eg t-
Butyl hydroperoxide / ascorbic acid) can be used. In this case, 20 to 98 ° C is an appropriate temperature. When copolymerizing a monomer with a macromonomer,
Chain transfer agents other than cobalt chelate compounds, such as mercaptans (ie, mercaptoethanol, t-dodecyl mercaptan, N-dodecyl mercaptan) can optionally be used.

A small amount of difunctional alpha-beta unsaturated compounds such as ethylene glycol dimethacrylate or hexanediol diacrylate can be used in the synthesis of the graft copolymer. by this,
Crosslinked particles are obtained.

The overall graft copolymer water borne dispersion has an acid or amine value of 10 to about 150 (mg / KOH / g resin solids), preferably 15 to about 250 ( mg / KOH /
g resin solids), more preferably 40-150 (mg /
KOH / g resin solids).

The binder systems described above are used in making waterborne coatings by mixing with other suitable ingredients by conventional film forming methods.

The graft polymers of the present invention are useful in film-forming vehicles in the synthesis of waterborne coating compositions such as automotive clearcoat or basecoat compositions.
ng vehicles). The coating composition made thereby has a low volatile organic content (VOC), preferably up to 3.50 lbs / gallon.

In preparing the coating composition, in accordance with another aspect of the present invention, the graft copolymer is 5 parts relative to the binder.
It can be combined with -20% by weight, preferably 10-40%, of crosslinker.

Suitable hardeners are melamine formaldehyde or alkylated melamine formaldehyde compounds,
Alternatively, one-part blocked or unblocked isocyanate compounds, or two-part isocyanate compounds, preferably water-dispersible polyisocyanates, or other cross-linking agents capable of reacting with cross-linking functionality on the graft copolymer. (Example: epoxy, silane, carbodiimide, etc.)
including.

When a binder is used in the compounding component which cures with a curing agent containing N-methylol and / or N-methylol ether groups, a water-based graft copolymer is used to make an overall stable dispersion. A curing agent is dispersed in the polymer dispersion. Such curing agents include, for example, reacting aldehydes (eg formaldehyde) with amino group-containing compounds (eg melamine, urea and benzoguanamine) and reacting with alcohols (eg methanol, n-butanol, isobutanol) in N 2 Obtainable by wholly or partially etherifying the methylol groups.

Preferred crosslinkers for forming a composition that crosslinks by raising the baking temperature to about 60 to 180 ° C. for about 5 to 60 minutes have 1 to 4 carbon atoms on the alkylated group. Of water-soluble, water-dispersible, alkylated melamine formaldehyde cross-linking agent, which is about 10-60% by weight, preferably 10-25% by weight, based on the weight of the binder.

The crosslinking agent is generally a partially alkylated melamine formaldehyde compound, which may be a monomer or a polymer, and the degree of polymerization of the polymer is about 1 to 3.
May be Typical alcohols used to alkylate such resins are methanol, ethanol, propanol, butanol, isobutanol and the like. Commercially available and suitable alkylated melamine cross-linking agents include Simel ™.
l) 373, 385, 1161, or 1168 (Monsanto) and Resimin (trademark: R
esimine) 714, Resimin (trademark: Resim
ine) 730 and 731, Resimin (trademark: Res
imine) 735 and 745 (Cyanamide (Cya
name)) is included.

For coating compositions containing a melamine crosslinker, about 0.1% to 1.0% by weight of binder of a strong acid or salt catalyst is included to reduce cure temperature and time. be able to. A preferred catalyst is paratoluene sulfuric acid or its ammonium salt. Other catalysts that can also be used are dodecylbenzenesulfonic acid, phosphoric acid, and the amine or ammonium salts of these acids.

When a binder is used in the compounding component that is cured by the polyisocyanate, the water-dispersible polyisocyanate is added to the water-supported graft copolymer dispersion prior to coating.

In this case, the dispersion as a whole is unstable and should be used within a limited time. Examples of water dispersible polyisocyanates include biuret and cyclotrimers of hexamethylene diisocyanate, isophorone diisocyanate and tetramethyl xylene diisocyanate. These isocyanates may be modified to the extent that they contain ionic groups so that they are easily dispersed in water.

Generally, a cure promoting catalyst is used in combination with an isocyanate crosslinking or curing agent. Preferred catalysts are organometallic compounds, which are effective in curing, usually from 0.1% to 2% by weight, based on the weight of the binder, of dibutyltin dilaurate, dibutyltin di-2.
Suitable are ethylhexoate, zinc octoate, zinc naphthenate, vanadium acetylacetonate, or zirconium acetylacetonate. Such catalysts are optional, for example elevated temperature and / or extended time may be sufficient to cure the composition.

Typical isocyanate crosslinkers that can be used to effect the coating composition include both compounds and polymers, both blocked and unblocked. Examples of suitable polyisocyanates are monomeric polyisocyanates (for example toluene diisocyanate and 4,4'-methylene-bis (cyclohexyl isocyanate)), isophorone diisocyanate, as well as the above-mentioned monomeric polyisocyanates and polyester or polyether polyols. NCO-prepolymers such as reaction products with Particularly useful isocyanates are isophorone diisocyanate and biuretized 1,6-hexamethylene diisocyanate, the latter being commercially available from Bayer, such as "Desmodur" N (N). . Other cross-linking agents include
4,4'-biphenylene diisocyanate, tetramethyl diisocyanate, ethylethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,
3-Phenylene diisocyanate, 1,5-naphthalene diisocyanate, bis (4-isocyanatocyclohexyl) methane and the like are included.

Trifunctional isocyanates may be used.
For example, triphenylmethane triisocyanate, 1,
3,5-benzenetriisocyanate, 2,4,6-toluenthisocyanate, an adduct of trimethylol and tetramethylxylene diisocyanate (trade name "Cythane 3160", a trimer of hexamethylene diisocyanate). Desmodur (De
smodur) "sold as N3390). For example, U.S. Pat. No. 4,965,317 (Co
l. As disclosed in 5), polyisocyanate acrylic copolymers derived from isocyanate ethyl methacrylate (commercially available as TMI) may optionally be used.

As mentioned above, the polyisocyanate may optionally be blocked. Examples of suitable blocking agents are substances that do not block at high temperatures, such as lower aliphatic alcohols (eg methanol), oximes (eg:
Methyl ethyl ketone oxime), and lactams (eg:
Epsilon caprolactam). The blocked isocyanate can be used to form a suitable one-part system. Also, polyfunctional isocyanates with free isocyanate groups can be used to form a two-part room temperature cure system. In these systems, the product and isocyanate curing agent are combined just prior to coating.

Preferably 0 to 50% by weight based on the weight of binder (and 45 based on the graft copolymer).
To 100% by weight) of other film-forming polymers may be used with the graft copolymer. Other film forming polymers are linear or branched and include acrylics, acrylourethanes, polyesters, polyesterurethanes, polyethers, and polyurethanes compatible with graft polymers.

Organic cosolvents are also commonly used in the composition.
In this case, in order to facilitate the formulation and application of the coating composition of the present invention, the minimum amount thereof is preferably less than 20% by weight based on the carrier. Also, an organic solvent compatible with the components of the above composition is used.

Of course, the amounts of graft copolymer, curing agent, and catalyst will depend to a large extent on various factors,
Among other things, it depends on the particular components of the composition and the intended use of the composition.

Various components may be optionally added to the composition used for the graft copolymer according to the present invention.
Such ingredients include pigments, pearls, fillers, plasticizers, antioxidants, surfactants, and rheology control agents.

In order to improve the weather resistance of the finish coatings produced by the coating compositions according to the invention, a UV stabilizer, or a combination of UV stabilizers, is used in an amount of about 0.1 to 5 parts by weight, based on the weight of the binder. % Can be added.
Such stabilizers include UV absorbers, screening agents, quenching agents, and certain hindered amine light stabilizers. Also, the antioxidant may be added in an amount of about 0.1 to 5% by weight based on the weight of the binder.

Useful and typical UV stabilizers include benzophenones, triazoles, benzoates, hindered amines and mixtures thereof. Specific examples of UV stabilizers are disclosed in US Pat. No. 4,591,533.
No.

The coating composition also contains conventional compounding additives. For example, Regiflow S (trademark: Res
iflow S) (polybutyl acrylate), BYK
Flow control agents such as 320 and 325 (high molecular weight polyacrylates); rheology control agents such as fumed silica, microgels, and non-aqueous dispersion polymers; and other additives.

Color / Clear Coat When the coating composition is used as a clear coat (top coat) for finishing, and applied on a color coat (base coat) to which a pigment has been added, a small amount of pigment is applied to the clear coat. By adding, an aesthetic effect such as a specific color or coloring property can be obtained.

By adding a pigment to the coating composition, it can be used as a color coat, a mono coat, a primer, or a primer surfacer.

[0134]

The following examples illustrate the invention. Parts and percentages are by weight unless otherwise indicated. All molecular weights disclosed herein were determined by gel permeation chromatography using polyester as a standard sample.

Example 1 This example illustrates a method of making a methyl methacrylate (MMA) oligomer chain transfer agent. The following components were used in this method:

[0136]

[Table 1]

A dry reactor (reactor) equipped with a stirrer, thermocouple, nitrogen gas pressurizer and cooler was used. Portion 1 was added to the reactor and heated to 80 ° C. Portion 2 was charged to the reactor at once. When the temperature stabilized, Portions 3 and 4 were charged to the reactor over 240 minutes and 300 minutes, respectively.
After adding Part 3, the reactor was held at reflux temperature for 30 minutes before cooling.

Example 2 This example illustrates the preparation of a macromonomer stabilizer made from methyl methacrylate and methacrylic acid (MMA / MAA = 60: 40 (weight ratio)). The following components were used in this method:

[0139]

[Table 2]

Part 1 was charged to a reactor equipped with a stirrer, thermocouple and nitrogen gas pressurizer. The reactor was brought into a reflux state. Portions 2-6 were manufactured in separate containers. Portion 2 was charged to the reactor at once.
Portions 3 and 4 were simultaneously charged to the reactor with charging rates of 12.04 g / min and 3.37 g, respectively.
/ Min. After adding part 4, part 5 is 3.3
It was added at a rate of 7 g / min. After adding Part 5, the addition of Part 6 was done at a rate of 3.37 g / min. (The addition of parts 6 and 3 is completed at the same time.) Following the addition of parts 3 and 6, the reactor was held at reflux for 30 minutes.

The macromonomer stabilizer (A) obtained was characterized by the following molecular weight data.

Number average molecular weight Mn = 1405 Weight average molecular weight Mw = 2353 Dispersion (disp.) = 1.68 Example 3 In this example, methyl methacrylate and methacrylic acid (MMA / MAA = 70: 30 (weight ratio)) were used. 2) shows a method for producing another macromonomer stabilizer produced from The following components were used in this method:

[0143]

[Table 3]

Part 1 was charged to a reactor equipped with a stirrer, thermocouple and nitrogen gas pressurizer. The reactor was brought into a reflux state. Portions 2-6 were manufactured in separate containers. Portion 2 was charged to the reactor at once. Portions 3 and 4 were simultaneously charged to the reactor with charging rates of 18.12 g / min and 4.91 g / min, respectively.
It was a minute. Once the addition of Portion 4 was complete, Portion 5 was added at a rate of 4.91 g / min. Once the addition of Portion 5 was complete, Portion 6 was added at a rate of 4.91 g / min. (The addition of parts 5 and 3 is completed at the same time.) Following the addition of parts 3 and 5, the reactor was held at reflux for 30 minutes.

The macromonomer stabilizer (B) obtained was characterized by the following molecular weight data.

Number average molecular weight Mn = 1206 Weight average molecular weight Mw = 2641 Dispersion (disp.) = 2.19 Examples 4 to 7 These examples are for the preparation of self-stabilizing graft copolymer emulsions according to the invention. Is shown. Reactants for forming the basic skeleton of the copolymer include styrene (STY) and 2-ethylhexyl acrylate (2-
EHA), methyl methacrylate (MMA) and the M
A mixture of MA oligomer chain transfer agents, which was 80% by weight based on the weight of the graft copolymer.
The weight ratio of each component in the mixture is 23:40: (17-
X): It was X. The reactants for forming the graft or graft copolymer arms are MMA / MAA (1
2/8 weight ratio),
This is 20% by weight based on the weight of the above graft copolymer.
Met. The following components were used in such a method.

[0147]

[Table 4]

Part 1 was charged to a 5 liter reactor equipped with a stirrer, thermocouple and nitrogen gas pressurizer. The mixture was heated at 85 ° C. and purged with nitrogen gas for 30 minutes. Part 2, 10% of part 3 and part 4
10% of that was charged to the reactor at one time. The reactor temperature was raised and once stabilized, the co-additions of Portions 3, 4 and 5 were carried out for 240 minutes, 270 minutes and 300 minutes, respectively. After the addition of Part 5, the reactor temperature was held for 60 minutes.

[0149]

[Table 5]

Examples 8 and 9 This example illustrates the method of making addition graft copolymers according to the present invention. This graft copolymer comprises 80% by weight of the above-mentioned graft copolymer component of STY (23),
2-EHA (40), MMA (17-X) and the MM
It was a reaction product of the A oligomer chain transfer agent (X) and 20% by weight of the graft copolymer component of MMA / MAA (14/6). The numbers in the above parentheses are weight ratios in the composite. The following components were used in such a method.

[0151]

[Table 6]

Part 1 was charged to a 2 liter reactor equipped with stirrer, thermocouple and nitrogen gas pressurizer. The mixture was heated at 85 ° C. and purged with nitrogen gas for 30 minutes. Part 2, 10% of part 3 and part 4
10% of that was charged to the reactor at one time. The reactor temperature was raised and once stabilized, the co-additions of Portions 3, 4 and 5 were carried out for 240 minutes, 270 minutes and 300 minutes, respectively. After the addition of Part 4, the reactor temperature was held for 60 minutes. The results are shown in the table below.

[0153]

[Table 7]

Example 10 This example demonstrates a waterborne clearcoat based on the use of a low molecular weight self-stabilizing latex with methylmethacrylate oligomers for molecular weight control.

[0155]

[Table 8]

The above components were sequentially added and mixed. The sample was stretched on glass and formed into a dry film structure approximately 2.0 mils thick to produce a clear gloss film. The panel was cured at 77 degrees Fahrenheit and 50% relative humidity. The results are shown in the table below.

[0157]

[Table 9]

Example 11 In the following ingredient table for waterborne clearcoat candidates, a methylmethacrylate oligomer was used for molecular weight control.

[0159]

[Table 10]

The above components were sequentially added and mixed. The sample was stretched onto glass and formed into a dry film structure approximately 2.0 mils thick. The panel was cured at 77 degrees Fahrenheit and 50% relative humidity. By stretching the above solution,
Dust free time 33 minutes, tack free time 4 hours,
A transparent gloss film having the properties shown in the following table was produced.

[0161]

[Table 11]

Example 12 The following ingredient table for waterborne clearcoats was based on the use of low molecular weight self-stabilizing latices with methylmethacrylate oligomers for molecular weight control.

[0163]

[Table 12]

Spraying of the above solution gave a clear film with very good gloss on a white basecoat.

Those skilled in the art can make various changes such as slightly changing the component amounts from the disclosed contents, adding harmless or supplementary substances, or substituting equivalent substances to those disclosed. Would not doubt to include a change of. Such changes are considered to be within the scope of the inventive concept as defined in the claims.

[0166]

According to the present invention, the graft copolymer of the present invention has almost no moisture-sensitive groups when used in a coating composition.

The graft copolymers of the present invention can also be used in compositions having lower amounts of surfactant or no surfactant at all.

In the present invention, since the hydrophilic macromonomer on the surface of the self-stabilizing latex is plasticized by water, a film is formed with less solvent or without solvent.
The coating composition can be formulated with a much lower VOC.

 ─────────────────────────────────────────────────── ———————————————————————————————— Inventor Michael Fried United States 08057 Morestown, New Jersey East Maple Avenue 50 (72) Inventor Charles Tee. Barge United States 19810 Wilmington Boxwood Drive, Delaware 2621 (72) Inventor Donald A .. White, Jr. 19701 Bear West Savannah Drive, Delaware 143

Claims (3)

[Claims] 1. A composition for a graft copolymer having a molecular weight of 3,000 to 500,000, which comprises the following reaction product: (a) 2 based on the weight of the graft copolymer. ~ 98
Wt% polymerized ethylenically unsaturated monomer to form the polymer backbone of the graft copolymer, (b) 98-2 based on the weight of the graft copolymer.
% Of macromonomer for attaching to said polymer backbone at its single end, having a molecular weight of 50
0 to 30,000 and comprising 10 to 100% polymerized α-β ethylenically unsaturated monomer having one of a carboxylic acid function or an amine function, based on the weight of the macromonomer. Macromonomer, (c) 1.0-based on the weight of the graft copolymer
20% by weight of one or more terminally unsaturated oligomers having a substantially lower average molecular weight and lower water solubility than the macromonomer of (b) above, provided that the carboxylic acid or amine At least a portion of the groups are neutralized, the macromonomer is soluble or dispersible in the aqueous carrier, stabilizes the graft copolymer moiety that forms insoluble particles, and the oligomer is It has the effect of limiting the molecular weight of the graft copolymer. 2. A coating composition comprising the graft copolymer according to claim 1. 3. A molecular weight of 3,000 to 500,000, wherein the following components are simultaneously reacted in an aqueous solvent.
No. 0 graft copolymer: (a) 2 to 98 based on the weight of the graft copolymer.
Wt% polymerized ethylenically unsaturated monomer to form the polymer backbone of the graft copolymer, (b) 98-2 based on the weight of the graft copolymer.
% Of macromonomer for attaching to said polymer backbone at its single end, having a molecular weight of 50
0 to 30,000 and comprising 10 to 100% polymerized α-β ethylenically unsaturated monomer having one of a carboxylic acid function or an amine function, based on the weight of the macromonomer. Macromonomer, (c) 1.0-based on the weight of the graft copolymer
20% by weight of one or more terminally unsaturated oligomers having a substantially lower average molecular weight and lower water solubility than the macromonomer of (b) above, provided that the carboxylic acid or amine At least a portion of the groups are neutralized, the macromonomer is soluble or dispersible in the aqueous carrier, stabilizes the graft copolymer moiety that forms insoluble particles, and the oligomer is It has the effect of limiting the molecular weight of the graft copolymer.