CA1259730A - Coating composition of an acrylic polymer having amino ester groups and a glycidyl acrylic polymer - Google Patents

Abstract

TITLE Coating Composition of An acrylic Polymer Having Amino Ester Groups And a Glycidyl Acrylic Polymer A coating composition which cures at ambient temperatures of 20-80% by weight of a binder and 80-20% by weight of a solvent for the binder, the binder contains about: A. 60-80% by weight, based on the weight of the binder, of an acrylic polymer of polymerized monomers of methyl methacrylate and an alkyl methacrylate, an alkyl acrylate or mixtures thereof, each having 2-12 carbon atoms in the alkyl group and the polymer has pendent amino ester or hydroxy amino ester groups; B. 20-40% by weight, based on the weight of the binder, of a glycidyl acrylic crosslinking polymer of polymerized monomers of glycidyl methacrylate or glycidyl acrylate and an alkyl methacrylate, alkyl acrylate or mixtures thereof, each having 2-12 carbon atoms in the alkyl group. The composition is useful as an exterior finish for automobiles and trucks and for repairing finishes of automobiles and trucks.

Description

5~3~3 _._ Coating Composition Of ~n Acrylic Polymer ~aving Amino Eater Groups ~nd A Glycidyl Acrylic Polymer BACXGROUND OF THE INVENTION
5This invention is related to a coating compo-sition and in particular to a coating composition that cures at ambient temperatures.
. ~any currently available coating com~ositions used to finish and repair the exterior finishes of trucks and automobiles ~ontain isocyanate compounds.
These compositions cure at ambient temperatures and provide finishes with good physical properties such as gloss, hardness, weatherability, good adhesion, chip ` resistan~e and the like. Typical composition~ are 15shown in Crawley et al. U.S. 4,131, 571 issued Decem-ber 26, 1978, ~iller U.S. 4,020,216 issued April 26, 1977; Miller U.S. 3,344,993 issued October 29, 1974, Miller U.S. 3,789,037 issued January 29, 1974 nnd Vast~ V.S. 3,558,564 issued Janu~ry 26, 1971. It would be desirable to provide ~n ambient temperature curing composition that does not contain an isocyanate compound but has all of the good properties of the aforementioned compositions.
The novel ~oating composition of this inven-tion does not contain isocy~nate compounds and cures at ambient temperatures and provides finishes that have excellent physical properties ~nd ~re useful for exterior finishes of nutomobiles ~nd trucks.
SUMMARY OF ~H~ INVENTION
30A coating composition containing about 20-80%
by weight ~f a binder and 80-20% by weight of a solvent for the binder, wherein the binder contains about :~25~3(~

(a) 60-80% by weight, based on the weight of the binder, of an acrylic polymer of polymerized monomers of methyl methacrylate and an alkyl methacrylate,an alkyl acrylate or mixtures thereof each having 2-12 carbon ~toms in the alkyl group and the polymer has pendent amino ester or hydroxy amino ester groups, and (b) 20-40% by w~ight, based on the weight of the binder, of a glycidyl acrylic crosslinking polymer of polymerized monomers of at least 60~ by weight, based on the weight of the crosslinking polymer, of glycidyl methacrylate or glycidyl acrylate ~nd an alkyl methacrylate, an alkyl acrylate or mixtures thereof each having 2-12 carbon ~toms in the alkyl group.
DETAILED DESCRIPTION
The coating composition contains about 20-80% by weight of binder and 80-20% by weight of a sol-vent for the binder. The binder is a blend of about 60-80% by weight of an acrylic polymer and 20-40% by weight of a glycidyl acrylic crosslinking polymer.
The composition can contain pigments in a pigment-to binder weight ratio of about 1:100-200:100.
The acrylic polymer i5 composed of polymerized monomers of methyl methacrylate, alkyl methacrylate, alkyl acrylate or mixtures thereof each having 2-12 carbon atoms in the alkyl group and has pendent amino ester groups or hydroxy amino ester groups.
The polymer has a number aver~ge molecular weight of about 3,000-15,000 and a weight aver~ge molecular weight of about 6,000 to 40,000.
Molecul~r weight is determined by gel permeation chromotography using polymethyl methacrylate as the standard.

~;~5~73~

One method for preparing the acrylic polymer is to polymerize monomera of methyl methacrylate, alkyl methacrylate,alkyl acrylate or mixtures thereof and methacrylic acid or acrylic acid and then post react the carboxyl groups of the resulting polymer with an alkylene imine to form pendent am~no ester groups fxom the backbone of the polymer.
The polymerization of the monomers to form the acrylic polymer is carried out by conventional techniques in which the monomers, solvents and polvmerization catalyst are charged into a polymeriza-tion vessel and re~cted at about 50-175C for about 0.5-6 hours to form the polymer.
Typical polymerization ca~alysts that are 15 used are azobisiosbutyronitrile, azo-bis(gamma dimethyl valeronitrilP), ~nd the like.

Typical solvents used are toluene, xylene, ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethanol, isopropanol and other ali-phatic, cycloaliphatlc and aromatic hydrocarbon esters, ethers, ketones and alcohols as are conventionally used.
One preferred acrylic polymer contains about 35-55~ by weight methyl methacrylate, 35-50%
by weight lauryl methacrylate or butyl methacrylate and 10-15% by weight methacrylic acid which polymer has been post reacted with an alkylene imine such AS propylene imine to provide amino ester groups pendent from the carbon-carbon polymer backbone of the formula where R is an alkylene group having 2-3 carbon atoms.

:~S3730 Another preferred acrylic polymer contains about 10-50% by weight styrene, an alkyl methacryla~e or an alkyl acrylate or mixtures thereof where the alkyl groups contain from 1-12 carbon atoms and methacrylic acid or acrylic acid which is post iminated with an alkylene imine to form aminoester groups pending from the backbone having the above formula. One particularly preferred acrylic polymer c~ntains about 20-50% by weight styrene, 30-70%
by weight of an alkyl methacrylate such as butyl methacrylate 10 and 10-15% by weight of methacrylic acid or acrylic acid post reacted with an alkylene imine such as propylene imine to provide amino ester groups having the above formula.
In an alternative method for preparing the acrylic polymer, monomers of methyl methacryl~te, 15 alkyl methacrylate, alkyl acrylate or mixtures thereof and glycidyl methacrylate or glycidyl acrylate are polymerized using the above solvents, polymerization catalyst and procedure. The resulting polymer and ammonia are charged into a pressure vessel 20 and heated to about 80-150~C and maintained at a pressure of about 14-35 kilograms per square centimenter tapproximately 200-500 pounds per square inch) for about 1 to 8 hours or until all of the glycidyl groups have been reacted with ammonia.
25 After the reaction of ammonia with the glycidyl groups of the polymer is completed, excess free ammonia is vacuum stripped off. The resulting polymer has hydroxy amino ester groups pending from the backbone of the polymer.
A prefe-red acrylic polymer prepared by tne alternative method contains about 40-50% by weight methyl methacrylate, 25-45% by weight of an alkyl acrylate or methacrylate such as butyl methacrylate or lauryl methacrylate and 5-20~ by 35 weight glycidyl methacrylate or glycidyl acrylate lZS~7~30 thathas been reacted with ammonia to form hydroxy amino ester groups pendent from the carbon-carbon polymer backbone of the formula O NH2 o OH
.. . .. .
-C-O-CH2-C-CH2-OH or -c-o-cH2-c-cH2 NH2 H H

An~ther preferred polymer prepared by the alternative method contains about 10-50~ by weight styrene, an alkyl methacrylate or an alkyl acrylate each having 1-12 carbon atoms in the alkyl group and glycidyl methacrylate or glycidyl acrylate that has been reacted with ammonia to form hydroxy amino ester groups pendent from the carbon-carbon polymer backbone having the above formulas. One particularly preferred acrylic polymer contains about 20-50% by weight of styrene 30-70% by weight of an alkyl methacrylate such as butyl methacrylate and 5-20% by weight of glycidyl methacrylate or glycidyl acrylate that has been reacted with ammonia to provide the aforementioned hydroxy aminoester groups.
The glycidyl acrylic crosslinking polymer is composed of.polymerized monomers of glycidyl methacrylate or glycidyl acryl~te and an alkyl 30 methacrylate,alkyl acrylate or mixtures thereof each having 2-12 carbon atoms in the alkyl groups and has a number average molecular weight of about 5,000-20,000 and a weight averaye molecular weight of about 6,000-40,000. Preferably, the polymer 35 contains about 60-85~ by weight of glycidyl 73(~
methacrylate and 15-40% by weight of an ~lkyl methacrylate such as lauryl methacrylate or butyl methacrylate. Other useful polymers contain about 40% by weight butyl methacryl~te/60%
glycidyl methacrylate and 20% butyl methacrylate/
80% glycidyl methacrylate.
Typical alkyl methacrylate and alkyl acrylate monomers that ~re used to prepare the aforementioned polymers are ethyl methacrylate, propyl methacrylate~ hutyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, ethyl hexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate,isobutyl acrylate, pentyl acrylate, hexyl acrylate, ethyl hexyl acrylate, nonyl acrylate, decyl acrylate,lauryl ~crylate and the like.
About 0.1-4~ by weight, based on the weight of the binder, of a catalyst can be added to the coating composition. Typical catalysts are resorcinol, resorcinol monobenzoate, boron trifluoride amine complex, phenol,para methoxy phenol, and hydroquinone.
As mentioned before, the composition can contain pi~ments. These pigments can be introduced into the composition by first forming a mill base with the acrylic polymer utilized in the composition or with other compatible polymers or polymer dispersants by conventional techniques, such as sand-grinding, ball milling, attritor grinding, two roll milling to disperse the pigments. The mill base is blended with the film-forming constituents as shown in the following Examples.
Any of the conYentional pigments used in coàting co~.positions can be utilized in the compo-1~Z5~73(~
7sitton such as the ~ollowing: metallic oxides, such as tTtanium dioxide, zinc oxide, iron oxide and the like, metal hydroxide, metal ~lakes such as aluminum flake, chromates, such as lead chromate, sulfides, ~ulfates, carbonates, carbon black, silica, talc, china clay, phthalocyanine blues and greens, organo reds, organo maroons and othex organlc pigments and dyes.
To improye weatherability of finishes of the coating composition about 0.1-5%, by weight, based on the ~eight of the binder, of an ultraviolet light stabilizer or a combination of ultraviolet light stabilizers can be added~ Typic~lly useful ultr~-violet light stabilizers are disclosed hereinafter.
The coAting composition of this invention can be applied over a variety of substrates, such as metal, wood, glass, plastic, and the like, by any of the con-ventional application methods, such as spraying, electro-static spraying, dipping, brushing, flow-coating and the like. The ~iscosity of the composition can be adjusted for any of these methods by adding solvents if neces-sary. Generally, the composition is utilized at a high solids content which keeps air pollution at a minimum level.
The coatings are usually dried at ambient temperatures and are tack free ~fter a~out 1-4 hours and ~ully cured after about 4-7 days, The coatings can ~e baked at relatively low temperatures of about 65-140C for ~bout 15 minutes - 2 hours. The resulting coating is ~bout 0.1-5 mils thick but for most uses, a 1-3 mil thick coating is used. One technique that is used to insure that there will be no popping or crater-ing of the coating is to allow the solvents to flash off for about 15-30 seconds before a second coating is sprayed on or otherwise applied, then waiting ~rom about 2-10 minutes before baking the coating to allow 12S9~3V
any residual solvents to flash off if the roating is to be baked. The resulting coating has good gloss and can be rubbed or polished with c~nventional techniques to improve the smoothness, appearance and gloss. The coating has good adhesion to suhstrates of all types, is hard and resistant to weathering, solvents, alkali, scratches and the like. These characteristics make the composition particularly useful as a finish for automobiles, trucks, airplanes, railroad equipment and for the repair of finishes of trucks and automobiles.
An4ther aspect of this invention is to utilize the composition as a clear coat/color coat finish for substrates. In this finish, a clear coat top layer is in firm adherence to a color coat layer that is in ad-herence with a-substrate. The clear coat is a ~rans-parent film of the coating composition of this invention and the color coat is the coating composition of this invention and contains pigments in a pigment-to-binder ratio of about 1/100 to 150/100 and other additi~es.
The thickness of the fully cured color coat and clear coat can vary. Generally~ the color coat is about 0.4-l.S mils thick and pref~rably 0.6-1.0 mils thick and the clear coat is about 0.5-6.0 mils thick and preferably 0.8-2.o mils thick. Any of the afore-mentioned conventional pigments can be used in the color coat including metallic flake pigments can be used. The clear coat can also contain transparent pigments, i.e~, pigments having the same or similar refractive index as the binder of the clear coat and are of a small particle size of about 00015-50 microns.
Typical pigments that can be used ~n a pigment-to-binder ~eight ratio of about 1/100 to 10/100 are inorganic siliceous pigments, such as silica pigments~ These pigments have a refractive index of about 1.4-1.6.
To form a durable finish, the clear coat .... . .. . .

~L~S97 ~nd optionally, the color coat contain ~b~ut 0.1-5% by weight based on the weight of the binder, of an ultra-violet light ~tabilizerO Typical ultraviolet light stabilizer6 that ~re useful are ns follows:
Benzophenoneæ ~uch as hydroxy dodecyloxy benzophenone, 2,4-dihydroxybenzophenone, hydroxyben-zophenones containing ~ulfonic groups and the like.
Triazoles ~uch as 2-phenyl-4-(2',4'-dihy-dryoxylbenzoyl)-triazoles, ~ubstituted benzotriazoles such as hydroxy-~henyltriazoles and the like.
Triazines such as 3,5-dialkyl-4-hydroxyphenyl deri~atives o triazine, ~ulfur containing derivatives of diallyl-4-hydroxy phenyl triazines, hydroxy phenyl -1,3,5-triazine and the like.
Benzoates ~uch as dibenzoate of diphenylol propane, tertiary butyl benzoate of diphenylol propane, and the like.
Other ultraviolet liyht ~tabilizers that can be used include lower alkyl thiomethylene containing phenols, substituted ~enzene~ ~uch as 1,3-bis-(2'-hydroxybenzoyl) benzene, metal derivatives of 3,5-di-t-butyl-4-hydroxy phenyl propionic acid, asymmetrical oxalic acid, diarylamides, alkylhydroxy-phenyl-thioal-kanoic ~cid ester and the like.
Particularly useful ultraviole~ light stabilizers that can be used are hindered amines of bipiperidyl derivatives such as those in Murayama et al,, ~.S. ~at. No. 4,061,616, issued December 6, 1977.
One preferred co~bination of ultr~violet light stabilizer is a benz~triazole and a hindered ~mine light st~bilizer and is preferably used in a weight ratio of ~bout 1:1. The combin~tion is used in an am~unt of about 1-4% by weight, based on the weight of the binder. One preferred benzotriazole is Tinuvin* 328, 2-(2 hydroxy-3,5-ditertiary amyl-phenol)-2H-b~nzotriazole and a *denotes trade mark 1;2 5~730 preferred hindered amine is "Tinuvin" 29~, bis(l,2,

2,6,6-pentamethyl-4 piperidinyl)sebacate. Another preferred hindered amine is "Tinuvin" 770, di[4(2,2,6,6 tetr~methyl piperdinyl)]sebacate.
The clear coat/color coat finish is ~pplied by conventional spraying techniques and preferably the clear coat is applied to the color coat while the color coat is still wet. Other conventional application techniques can be used such as brushing, roller coating, electrostatic spraying and the like. The finish is then dried at ambient temperatures or can be used as indi-cated above.
The ~ollowing Examples illustr~te the in~en-tion. All parts and percentages are on a weight basis unless otherwise indicated. The number and weight average molecular weights are determined by gel permeation chromatography using polymethyl methacrylate as A standard.

An iminated acrylic polymer solution was prepared by charging the following constituents into a reaction vessel equipped with a heating mantle, reflux condenser and a stirre~:
Parts by Weight Portion 1 Toluene 597.0 Isopropanol 268.0 Methyl methacrylate monomer 68.0 Portion 2 Methyl methacrylate monomer 452.0 Lauryl methacrylate monomer 624.0 Methyacrylic acid monomer 137.0 Azobisisobutyronitrile 21.6 Portion 3 Methacrylic acid monomer 1~.7 Toluene 40.8 :~ZS~73~

Portion 4 :
Toluene 1002.0 Portion 5 Propylene imine 118.0 Total3348.1 Portion 1 was charged into the reaction vessel and heated to its reflux temperature. While maintain-ing the constituents in the vessel at the reflux tempera-ture, Portion 2 was ~dded at a uniform rate over about l-l/2 hours to form a polymeric reaction mixture.
After Portion 2 was added, Portion 3 was added over a 45 minute period at a uniform rate to the xeaction mixture and held at xeflux tempexature for 45 minutes. Portion 4 was then added and heat was turned off and the reaction mixture was allowed to cool to about 60C. Portion 5 was added and the reaction mixture was held at its reflux temperature for about 6-l/2 hours.
The resulting polymer solution had a polymer weight solids content of about 43.3%, and a relative viscosity measured at 25C o~ 1.0669. Th~ polymer has a composition of ~8~ lauryl methacrylate, 40~
methyl methacryl~te, 12% methacrylic acid postim~ted with propylene imine. The polymer had an acid number of 1.8, a calculated glass transition temperature of ~20C, a number average molecular weight of ll,100 and weight average molecular weight of 29,400.
A glycidyl acrylic crosslinking polymer solution was prepared by charging the following consti-0 tuents into a polymerization vessel equipped ~s above: -Parts by Weight Portion l Toluene 765.0 Methyl ethyl ketone 344,0 5 ~;~5973~

Portion 2 Glycidyl me~hacrylate 999.0 Lauryl methacrylate 666.0 Azobisisobutyronitrile 16.6 Toluene 10.5 5 P rtion 3 Methyl ethyl ketone 69.8 ~ Azobisisobutyronitrile 3.0 ¦ Total2873.9 ¦ Portion 1 is charged into the polymerization vessel and heated to its reflux temperature. Portion 2 is added at a uniform rate over a 90-minute period.
After Portion 2 was added, Portion 3 is ~dded over a one-hour period and the resulting mixture was held at its reflux temperature for an ~dditional 30 minutes and then cooled to room temperature.
The resulting polymer solution had a polymer solids content of 56.~% and a relative viscosity measured at ?5C of 1.0682. The polymer had th~ following com-position: 60% glycidyl methacrylate and 40% lauryl methacrylate and has a number average molecular weight of 11,000 and a weight a~erage and molecular weight of 32,5~0.
A white mill base was prepared by charging the following constituents into a sand mill and grinding the constituents until the pigments were thoroughly dispersed:
Parts by Weight Dispersing resin solution (55% 24.73 solids in organic solvent of a polymer of 40% methyl methacrylate, 33% butyl methacrylate, 5% diethyl amino ethyl methacrylate, 7% hydroxy ethyl acrylate, 15% vinyl-oxazoline linseed oil fatty ~cid ester) ~259~3(~

Butyl acetate 4.5~
~ro~atic hydrocarbon Rolvent 3.38 Aliphati~ hydrocarbon solvent 9~31 Titanium dioxide pigment 58.00 Total lOQ,oo A green mill base w~s prepared by charg-ing the following constituents into ~ sandmil~
and grinding the constituents un~il the pigments were thoroughly dispersed:
Parts by Weight 10 Dispersing resin ~olution 44 23 (described above) - -Xylene 26.09 Butyl acetate 7.29.
Aliphatic hydrocarbon solvent 26.09 Monastral* green pigment 10.50 Total114.20 A blue mill bases ~as prepared ~y charg-ing the following constituents into a ball mill and grinding the constituents until the pigments were 20 thoroughly dispersed:
Parts by Weight Dispersing resin solution 32.90 (described above) Xylene 30.22 Toluene 29.18 25 "Monastral" blue pigment 7.70 Total100.00 A black mill base was prepared by charging the following constituents into a ball mill and grinding the constituents until the pigments were 30 thoroughly dispersed:
Parts by Weight Dispersing resin solution 54.90 (descri~ed above) Xylene 33 0O
Carbon black pigment 12.10 Total100.00 *denotes trade mark . . .

:1~59~30 . 14 An aluminum flake mill base was prepared ~y thoroughly mixing the following:
Parts_by Weight Dispersing resin solu~ion 55.08 (described above) Xylene 7.42 Butyl acetate 6.00 Aliphatic hydrocarbon solvent 13.50 Medium coarse aluminum paste 18.00 Total100.00 A composite white mill base was prepared by mixing the follswing:
White mill b~se(prepared above) 99.60 Black mill base(prepared above) 0,40 Total 100.00 A dark green metallic composite mill base was prepared by mixing the ~ollowing:
Parts by Weight Black mill base(prepared above) 27.26 Green mill base(prepared above) 64.95 Aluminum flake mill base 7.79 (prepared above) Total100.00 . A light blue metallic composite mill base was prepared by mixing the following:
Parts by Weight 25 Green mill base(prepared abo~e) 1.51 Blue mill base(prepared above) 13.59 Aluminum flake mill base 84.90 (prepared above) Total100.00 The following paints A-F were prepared as shown in Table I by thorvughly blending the constituents listed in a mixer.

12S~373~
~ABLE I
(Parts by Weight) Paints A B C D E F
~osite white mill base 249 Z49 5 DHrk green metallic - - 87 87 - -composite mill base Light blue metallic - - - - 74 74 o~site mill base ~Tmuvinn328-2-(2 hydr~ 3 33.4 3,4 3.4 3.4

3,5 di-~t~y ~myl-10 phenol~ZH-b~otriazole ~Tinuvinn292-bis(1,2,6,6- 3 3 3.4 3 4 3-4 3 4 pent~et~yl-4 piperi-dinyl)~c~te Imlnated acrylic poly- 514 514559 559572 572 mer 801ut~ on (pre-15 pared above) Silicone oil solution0.7 0.70.8 0.80.8 0.8 (2~ s~licone oil in ~rganic solvent) Isopropanol 11 11 12 12 12 12 Resorcinol - 13.2 - 13.6 - 13.8 Glycidyl ~crylic cross 116116 126126 130 130 linking polymer solution (prepared above) Each of the above paints was reduced to a spray viscosity of 23 seconds measured with a #2 Zahn cup with a solvent blend of 70% xylene, 10% Butyl Cellosolve*Acetate and 20% dimethyl esters of C4-C6 dibasic acids. Two sets of panels were prepared with each paint. The steel p~nels were primed with an alkyd resin primer and coated with an acrylic lacquerprimer surfacer which was sanded.
One set of panels was dried at ambient temperatures for 7 days and the second set of panels was baked at about 80C for about 30 minutes and then allowed to stand ~t ambient temperatures for 7 days.
The resulting dry film thickness on each of the panels was about 2.1-2.4 mils.
*denotes trade mark 15 .

3~Z~i~73~

All of the painted panels had good gloss and distinctness of image and had excellent resistance to weathering. Both sets of panels showed excellent resistance to water spotting, gasoline, gasohol, cer-!, tain solvents such as methyl ethyl ketone, ~sphaltand grease.
EX~P~E 2 An ammoni~ted acrylic polymer solution was prepared by charging the following constituen~s into a reaction Yessel equipped as in Example 1:
Parts by Weight Portion 1 Methyl methacrylate monomer 761.0 Butyl methacrylate monomer 360.0 Glycidyl methacrylate monomer 79.0 Toluene 500 0 Isopropanol 200 0 Portion 2 A~obisisobut~ronitrile 14.0 Toluene 250.0 Portion 3 ~' Azobisisobutyronitrile 7.5 Toluene 300.0 Portion 4 Toluene 26.0 Isopropanol ~952.0 Total3449.5 Portion 1 was ~harged into the reaction ves-sel and heated to its reflux t~mperature of ~bout 90C.
About 25% of PDrtion 2 was added rapidly nnd the remainder of Portion 2 then was added over a 20 minute period and 30 the resulting reaction mixture was held at its reflux temperature for an additional 90 minutes. Portion 3 was added over a 30 minute pexiod and the reaction mixture was held at its reflux temperature for an ~Z5~73(~

additional 90 minutes. Portion 4 was added and the resulting polymer solution was cooled to an ambient temperatureO The polymer solution was charged into a pressure vessel with aImmonia and heated to about 100C and held under a pressure of about 14-35 kilograms per square centimeter (about 200-500 pounds per square inch) and reacted for about 6 hours until all of the glycidyl groups reacted with ammonia. Excess ~mmonia w~s 10 then vacuum stripped from the solution.
The resulting polymer solution had a polymer weight solids content of 3S.5% and a relative viscosity of 1.13-72 measured at 25Co The polymer had a compo-sition of 63.4% methyl methacryl~te, 30~ butyl metha-15 crylate and 6.6. hydroxy ~mino ester a post reactionof ammonia with glycidyl methacrylate and had a number average molecular weight of 7,800 and weight average molecular weight of 36,000.
The following glycidyl acrylic polymer solu-tions were prepared using the same polymerization pro-cedure a~ in Example 1 except butyl methacrylate was substituted for lauryl methacrylate in the amounts as shown below:
40~ ~MA/60~ GMA Solution (55~ polymer solids solution of 40~ butyl methacrylate/60% glycidyl methacrylate polymer having a number average molecular weight of about 12,000 and a weight average molecular weight of about 23,000);
20% BMA/80~ GMA Solution ~55% polymer solids solution of 20% butyl methacrylate/80% glycidyl ~ethacrylate polymer having a number average 373~

molecular weight of about 12,000 and a weightaverage molecular weight of about 23,0U0).
The following paints G and I were prepared as shown in Table II ~y thoroughly blending the consti-5 tuents in a mixer:
TABLE II
(Parts by Weight) Paint G
-Light blue metallic coo~osite60.4 60.4 mill base (prepared in Ex~mple 1) Ammoniated acrylic polymer 591.0 604.0 solution (prepared above) 40~ BMA/60% GMA solution3~.0 20% Br~/80~ GM~ solution - 28.0 nTinuvin" 770 di[4(2,2,- 2.6 2.6 6,6 tetramethyl piperi-dinyl)]sebacate Each of the above paints was reduced ~o spray viscosity described in Example 1 with the solvent de-scribed in Example 1. A set of steel panels was pre-pared with each paint. The panels were each primed with an alkyd resin primer and coated with an acrylic lacquer primer surfacer which was sanded.
Each of the panels was tack free in ~bout 1 hour, had ~ gloss measured at 20 of 46-48, a distinctness of image of greater than 50, gasoline resistant after 72 hours, toluene resistant after 192 hours, had excellent wet adhesion, was chip resist nt and did not blister.

~1 25~73(~
19 ' An iminated acry.lic polymer solution was prepared by charging the following constituents into a reaction vessel equipped as in Example 1:
Parts by Portion 1 Weight Toluene 1532 Isopropanol 689 Butyl methacrylate monomer 176 Portion 2 .
Butyl methacrylate monomer 1827 Styrene monomer 933 Methacrylic acid monomer 350 Azobisisobutyronitrile 87 Toluene 141 Portion 3 Toluene 105 Methacrylic acid monomer 51 Portion 4 20 Toluene 2430 Portion 5 Propylene imine 319 Total 8640 Portion 1 was charged into the reaction vessel and heated to its reflux temperature while maintaining the constituents in the vessel at the reflux temperature.
Portion 2 was added at a uniform rate over about 1.1/2 hours to form a polymeric reaction mixture. After portion 2 30 was added, portion 3 was added over a 15 minute period and the reaction mixture was held at its reflux temperature for an additional hour. Portion 4 was added and then portion 5 was added and the reaction mixture was held at its reflux temperature until the acid no. of the polymer was 2 or less.
The resulting polymer solution has a polymer weight solids content of about 42.3% and a relative viscosity ~;~5!~73(~

measured at 25C of 1.067. The polymer has the following composition 28~ styrene, 60% butyl methacrylate, 12%
methacrylic acid post iminated with propyleneimine.
~he following clear composition was formulated:
Parts by Wei~ht Iminated acrylic polymer 311.4 solution(prepared above) Silicone Oil Solution 0.4 (described above) 10 Isopropanol 6.7 "Tinuvin" 328(described in 1.7 Example l) "Tinuvin" 292 (described in 1.7 Example 1) --Total 321.9 100 parts of the above clear composition was blended with 20.8 parts of the 40% BMA/60% GMA solution described in Example 2 to form a clear coating composition.
As in Example 1, the clear coating composition was reduced to a spray viscosity using the solvent blend of Example 1 2~ Paints A-F of Example 1 and Paints G and I of Example 2 were each sprayed into two sets of steel panels primed with an alkyd resin primer and coated with an acrylic lacquer primer surfacer which was sanded. After fla~h drying the panels for a relatively short time, e.g. 5-10 minutes, the above prepared clear coating composition was applied to the panels. One set of panels was dried at ambient temperatures for 7 days and the second set of panels was baked at 80C for about 30 minutes and then kept at ambient temperatures for 7 days. Each Of the resulting panels had excellent gloss and distinctness of image and had excellent resistance to weathering. Also, the panels showed good resistance to water spotting, gasoline, gasohol and solvents such as methyl ethyl ketone and resistance to asphalt and grease.

Claims (12)

1. A coating composition comprising 20-80% by weight of a binder and 80-20% by weight of a solvent for the binder, wherein the binder consists essentially of about:
A. 60-80% by weight, based on the weight of the binder, of an acrylic polymer consisting essentially of polymerized monomers selected from the group consisting of methyl methacrylate and 10-50% by weight styrene and monomers selected from the group consisting of alkyl methacrylate and alkyl acrylate each having 1-12 carbon atoms in the alkyl group and said polymer having pending from the carbon-carbon atoms of the polymer backbone aminoester groups of the formula where R is an alkylene group having 2-3 carbon atoms or hydroxyamino ester groups of the formula B. 20-40% by weight, based on the weight of the 21a binder, of a glycidyl acrylic crosslinking polymer of polymerized monomers having at least 60% by weight of a glycidyl constituent selected from the group consisting of glycidyl methacrylate and glycidyl acrylate and polymerized monomers selected from the group consisting of alkyl methacrylate and alkyl acrylate each having 2-12 carbon atoms in the alkyl group;
said polymers having a weight average molecular weight of about 6,000-40,000 determined by gel permeation chromatography using polymethyl methacrylate as a standard.

2. The coating composition of claim 1 containing pigments in a pigment-to-binder weight ratio of 1:100 to 200:100.

3. The coating composition of claim 1 in which he acrylic polymer consists essentially of about 35-55% by weight, based on the acrylic polymer, Of methyl metahcrylate, 35-50% by weight, based on the weight of the acrylic polymer, of lauryl methacrylate or butyl methacrylate and 10-15% by weight, based on the weight of the acrylic polymer, of methacrylic acid; said polymer reacted with an alkylene imine to provide amino ester groups pendent from the carbon-carbon polymer backbone of the formula where R is an alkylene group having 2-3 carbon atoms.

4. The coating composition of claim 1 in which the glycidyl acrylic crosslinking polymer con-sists essentially of about 60-85% by weight, based on the weight of the glycidyl acrylic crosslinking polymer, of glycidyl methacrylate and 15-40% by weight, based on the weight of the glycidyl acrylic crosslinking polymer, of lauryl methacrylate or butyl methacrylate.

5. The coating composition of claim 1 in which the acrylic polymer consists essentially of 40-50% by weight, based on the weight of the acrylic polymer, of methyl methacrylate, 25-45% by weight, based on the weight of the acrylic polymer, of butyl methacrylate or lauryl methacrylate and 5-20%
by weight, based on the weight of the acrylic polymer, of glydicyl methacrylate, said polymer being reacted with ammonia to provide hydroxy amino ester groups pendent from the carbon-carbon polymer backbone of the formula

6. The coating composition of claim 1 con-taining about 0.1-44 by weight, based on the weight of the binder, of a catalyst selected from the group consisting of resorcinol, resorcinol monobenzoate, boron trifluoride amine complex, phenol, para methoxy phenol and hydroquinone.

7. The coating composition of claim 1 containing 0.1-5% by weight, based on the weight of the binder, of ultraviolet light stabilizer.

8. The coating composition of claim 1 con-taining pigments in a pigment-to-binder weight ratio of about 10:100 to 150:100, wherein the binder consists essentially of:
A. An acrylic polymer consisting essentially of about 35-55% by weight, based on the weight of the acrylic polymer, of methyl methacrylate, 35-50% by weight, based on the weight of the acrylic polymer, of lauryl methacrylate and 10-15% by weight, based on the weight of the acrylic polymer of methacrylic acid, said polymer reacted with propylene imine to provide amino ester group pendent from the carbon-carbon polymer backbone of the formula where R is an alkylene group of 3 carbon atoms;
B. a glycidyl acrylic crosslinking polymer consisting essentially of about 60-85% by weight, based on the weight of the glycidyl acrylic crosslinking polymer, of a glycidyl methacrylate and 15-40%
by weight, based on the weight of the glycidyl acrylic crosslinking polymer, of lauryl methacrylate;
C. about 0.1-4% by weight, based on the weight of the binder, of a catalyst selected from the group consisting of resorcinol, resorcinol monobenzoate, boron trifluoride amine complex, phenol, para methoxy phenol, and hydroquinone;
and D. about 0.1-5% by weight, based on the weight of the binder, of ultraviolet light stabilizer.

9. The coating composition of claim 1 con-taining pigments in a pigment-to-binder weight ratio of about 10:100 to 150:100, wherein the binder consists essentially of A. an acrylic polymer consisting essentially of 40-50% by weight, based on the weight of the acrylic polymer, of methyl methacrylate, 25-45%
by weight, based on the weight of the acrylic polymer, of lauryl methacrylate and 5-10% by weight, based on the weight of the acrylic polymer, of glycidyl methacrylate, said polymer reacted with ammonia to provide hydroxy amino ester groups pendent from the carbon-carbon polymer backbone of the formula B. glycidyl acrylic crosslinking polymer consisting essentially of about 60-85% by weight, based on the weight of the glycidyl acrylic crosslinking polymer, of glycidyl methacrylate and 15-40% by weight, based on the weight of the glycidyl acrylic crosslinking polymer, of lauryl methacrylate;
C. about 0.1-4% by weight, based on the weight of the binder, of a catalyst selected from the group consisting of resorcinol, resorcinol monobenzoate, boron trifluoride amine complex, phenol, paramethoxy phenol and hydroquinone; and D. about 0.1-5% by weight, based on the weight of the binder, of ultraviolet light stabilizing agent.

10. A substrate coated with a dried layer of the composition of claim 1.

11. The coating composition of claim 1 in which the acrylic polymer consists essentially of about 20-50%
by weight, based on the acrylic polymer, of styrene, 30-70% by weight, based on the weight of the acrylic polymer, of butyl methacrylate and 10-15% by weight, based on the weight of the acrylic polymer, of methacrylic acid; said polymer reacted with an alkylene imine to provide amino ester goups pendent from the carbon-carbon polymer backbone of the formula where R is an alkylene group having 2-3 carbon atoms.

12. The coating composition of claim 4 in which the acrylic polymer consists essentially of 20-50% by weight, based on the weight of the acrylic polymer, of styrene, 30-70% by weight, based on the weight of the acrylic polymer, of butyl methacrylate and 5-20%
by weight, based on the weight of the acrylic polymer, of glycidyl methacrylate, said polymer being reacted with ammonia to provide hydroxy amino ester groups pendent from the carbon-carbon polymer backbone of the formula