CA1045276A - Powder coating composition comprising a copolymer of a glycidyl ester and a crosslinking agent - Google Patents

Abstract

POWDER COATING COMPOSITION COMPRISING
A COPOLYMER OF A GLYCIDYL ESTER AND
A CROSSLINKING AGENT

ABSTRACT OF THE DISCLOSURE

Improved powder coating compositions are disclosed which comprise (1) a copolymer of about 5 to about 20 weight percent of a glycidyl ester of a monoethylenically unsaturated carboxylic acid, e.g., glycidyl acrylate and glycidyl meth-acrylate, about 2 to about 10 weight percent of a monomeric alpha-beta olefinically unsaturated amide and about 70 to about 93 weight percent of other olefinically unsaturated monomers, preferably monofunctional olefinically unsaturated monomers which lose their sole functionality in polymeriza-tion and (2) as crosslinking agents, both hydroxy carboxylic acids and anhydrides, preferably polyanhydrides.

Description

The present invention relates to powder coating compositions.
Powder coating compositions are extremely desirable f~r use in painting substrates in that they are essentially free of organic solvents conventionally utilized in liquid paint systems. Thus, they give off little, if any, volatile material to the environment when heat cured.
Powder coatings comprising (1) a copolymer of a - glycidyl acrylate and other olefinically unsaturated monomers, (2) a dicarboxylic acid crosslinking agent, and (3) a polymeric flow control agent was heretofore described in U.S. Patent 3,752,870 issued August 14, 1973 to Santokh S.
Labana.
Powder coating materials comprising (1) a copolymer ` 3 of a glycidyl acrylate and otheir olefinically unsaturated `:~ monomers, (2) a crosslinking agent comprising a mixture of -`~ a monocarboxylic acid and a dicarboxylic acid, and (3) a ~. .
~ polymeric flow control agent were heretofore described in .,.~
U.S. Patent 3,730,930 issued May 1, 1973 to Santokh S. Labana.
Powder coating materials comprising (1) a copolymer of a hydroxy acrylate and other olefinically unsaturated monomers, (2) a crosslinking agent selected from anhydrides, dicarboxylic acids, and melamines, and (3) a polymeric flow -~ control agent were heretofore described in Canadian Patent ; No. 979,136.
Powder coating materials comprising (1) a copolymer :~ .
; of a glycidyl acrylate and other olefinically unsaturated nomers, (2) an anhydride (monomeric and polymeric) cross-,.
linking agent, and (3) a polymeric flow control agent was heretofore described in U.S. Patent No. 3,7~1,379.
It now has been discovered that the addition of -~
. ~, ~ .
-- 2 ~
., ~

.,~, , . . , ~ . .

1045Z7~, hydr~xy carboxylic acids to an epoxy-functional and amide-functional copolymer and an anhydride, preferably polyanhydride, -~coating system provides coating powders with excellent flow-ability and functional group conversion upon curing even at .;..................................................... .
;- temperatures lower than those conventionally used for curing acrylic based powder coatings. The coatings obtained by baking these powders at 300F for 20-30 minutes have excellent gloss, adhesion to metals, hardness and solvent resistance.
Further, the use of the aforementioned copolymer of dual functionality facilitates compatibility of the complete coating composition.
Except in those instarlces wherein a specific .~ .
compound is named, the term "acrylate" is used in this specification to include esters of both acrylic acid and methacrylic acid, i.e., acrylates and methacrylates.
These powders are effectively prepared by spray . .,.~ . .
drying in that they resist phase separation. They may also . :~
~ be processed by melt blending and vacuum drying techniques.
.. , . :
They are easily and effectively mixed by extrusion or mill rolling. Further, the need for an antistatic agent is ... ~ . -:
eliminated when a film depth of less than 4 mils (0.004 in.) `~ is to be applied.

Epoxy and amide functional copolymers suitable for use in the powder coating materials of this invention : . .
are readily formed by conventional free radical induced polymerization of suitable alpha-beta olefinically ~nsaturated monomers. These copolymers having both pendant epoxide groups and pendant amide groups are potentially self-cross-" . ~
linking but the epoxy-amide reaction is very slow and requires large amounts of catalyst to accelerate the curing reaction. Thus, in this invention, a crosslinking agent, i.e., ''.

;, ':
:.
-. -a hydroxy carboxylic acid and an anhydride, are added to the paint binder system.
The copolymers used in this invention contain between about 5 and about 20, preferably between 8 and 15, weight percent of a glycidyl ester of a monoethylenically unsaturated carboxylic acid, e.g., glycidyl acrylate and glycidyl meth-acrylate. These monomers provide the copolymer with its epoxy functionality. The amide functionality is provided ~, , by incorporating in the unsaturated monomer polymerization - 10 mix about 2 to about 10 weight percent of a monomeric alpha-beta olefinically unsaturated amide, which is preferably acrylamide or methacrylamide.
~, The remainder of the copolymer consists essentially ~: of monofunctional, alpha-beta ~lefinically unsaturated monomers which are esters of Cl to C8 monohydric alcohols and acrylic or methacrylic acid or C8 to C12 monovinyl hydrocarbons.
Preferably, in excess of fifty (50) weight percent of the ~! copolymer monomers are esters of a Cl - C8 monohydric alcohol and acrylic or methacrylic acid, i.e., methyl methacrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, hexyl `. J acrylate, and 2-ethyl hexyl methacrylate. C8 - Cg monovinyl ~;
l hydrocarbons such as styrene, alpha methyl styrene, ~inyl -~ toluene, t-butyl styrene, chlorostyrene, and alpha methyl styrene are suitable for use but preferably comprise less than fifty (50) weight percent of the copolymer. Other vinyl monomers such as vinyl chloride, acrylonitrile, methacrylonitrile and vinyl acetate may be used as modifying monomers. When employed these comprise between 0 and 30 -~ percent by weight of the monomer miXture.
;~ 30 The epoxy-functional and amide-functional copolymers ~ used in these coating compositions have a glass transition ,, , , ~
~ - 4 -,: ,. ,: : ,~ :

` 1045276 .. . .
temperature in the range of 40C to 90C, preferably between 50c and 80C, and a molecular weight (Mn) in the range of about 1500 to about 15,000, preferably about 2500 to about 6 0 0 0 ~
In preparing this copolymer, the epoxy-functional monomer, e.g., glycidyl methacrylate, and the amide-functional monomer, e.g., methacrylamide, are mixed with the aforemen-tioned ethylenically unsaturated remainder monomers and reacted by conventional free radical initiated polymerization in such proportions as to obtain the copolymer for the ~ ë
`~, powder coating : .
,.. ~ ; . ~
`! :

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`,ii ; :

',s ~ :
, ~j j.i, ' s 1 :
:`,~, . ~
~` ~
: , . '." .
. ~ I
"

.
- 4a -.; r 10452~76 compositions. Thus, when the preferred ethlenically un-saturated remainder monomers are used with the epoxy-functional monomer and the amide-functional monomer to form the copolymer, the epoxy-functional monomer, e.g., glycidyl methacrylate, is present in the copolymer from about 5 weight percent to about 20 weiyht percent, the amide-; functional monomer, e.g., methacrylamide is present in the copolymer from about 2 to about 10 weight percent, and the preferred remainder monomers are present from about 93 to about 70 weight percent. Gènerally, a free radical initia-tor is needed to induce the polymerization reaction. A
large nu~ber of free radical initiators are known to the ~ 1 .
~, art and are suitable for this purpose. These include benz-~, oyl peroxide, lauryl peroxide, t-butylhydroxyperoxide, -acetylcyclohexane sulfonyl peroacide, diisobutyryl peroxide, .
di-(2-ethylhexyl peroxydicarbonate, di-isopropyl peroxydi-carbonate, t-butyl-peroxypivalate, decanoyl peroxide, ,~ , ;, azobis (2-methylpropionitrile, etc. The polymerization is ` preferably carried out in solution using a solvent in which , -2Q the epoxy-functional, amide-functional copolymer is soluble.
~ Toluene, xylene, dioxane, butanone, etc.,`are suitable ; solvents for this polymerization. If the epoxy-functional, . ~ .
amide-functional copolymer is prepared in solution, the solid copolymer can be precipitated by pouring the solution at a slow rate into a non-solvent for such copolymer such as hexane, octane or water under a suitable agitation condition. The copolymer thus obtained is further dried so that it contains less than three percent of the mater-ials that volatilize at the temperatures used for baking the coatings.

:~ .
'' ... . .. . .
:.~... . .. :
' :~ . - ' : ;: . . .

These copolymers can also be prepared by emulsion polymerization, suspension polymerization, bulk polymerization or their suitable combinations. In these :;
methods of preparing the copolymers, chain transfer agents may be required to control the molecular weight of the co-polymer to a desired range. The solid copolymers obtained by these methods must also be dried to contain less than three percent of the materials that volatilize at the temperatures used for baking the coatings.
- 10 For powder coating applications, both molecular weight and molecular weight distribution of the epoxy-functional, amide-functional copolymer are important.
While the lecular weight (Mn) range extends from about 1500 to about 15,000, the copolymer component must not contain significant amounts of higher molecular weight ~
: ~
fractions. No more than 5 percent of the copolymer should ~i be of molecular weight greater than 20,000. The molecular `~ weight distribution as measured by the ratio of weight '~1 average to number average molecular weight (Mw/Mn)should be in the range of 1.6 to 3Ø The preferred range of molecular weight distribution as in the range of 1.7 to 2.2.
These powder coating compositions include as ~, crosslinking agents for the aforedescribed copolymers both hydroxy carboxylic acids and anhydrides, preferably poly-i anhydrides.
Hydroxy carboxylic acids with melting points in the range of about 40 to about 150C. are suitable for use as crosslinking agents in these powders. These include -s such hydroxy carboxylic acids as 12-hydroxy stearic, 10-hydroxy octadecanoic acid, 3-hydroxy octadecanoic acid, 2-~ . , , 1 -,. -, .
.
. ~, , , - . .
c'.

hydroxy myristic acid, 2-hydroxy octadecanoic acid, etc.
The anhydride crosslinking agent may be either monomeric or polymeric, preferably polymeric, and is employed in an amount such as to provide about 0.3 to about 1.2 anhydride groups per functional group, i.e., epoxy and amide groups in the copolymer. The hydroxy carboxylic acids are employed in an amount of about 0.1 to about 0.4 hydroxy carboxylic acid groups per functional group.
Where the anhydride is monomeric, the preferred anhydrides are selected from the group consisting of phthalic anhydride, p-chloro phthalic anhydride, tetra-bromo phthalic anhydride, cyclohexane - 1,2 - dicarboxylic j anhydride, 4-methylhexane - 1,2 - dicarboxylic anhydride, cyclopentane - 1,2 - dicarboxylic anhydride, dicarboxylic -: .
anhydride, dodecyl succinic anhydride, succinic anhydride, maleic anhydride, methyl succinic anhydride and azelaic anhydride. In general, the preferred monomeric anhydrides are those which are ring compounds having a melting point ~` ~0 in the range of about 35C. to 140C.
Where the anhydride is polymeric, the preferred polyanhydrides are polyadipic anhydride, polyazelaic anhydride, and polysebasic anhydride but others having a polymeric molecular weight up to about 5000 are useful.
Those having a polymeric molecular weight in the range of about 1000 to about 2500 are preferred.
These powder coating compositions advantageously contain a flow control agent as a part of the powder coating mixture. The flow control agent is a polymer ` 30 having a molecular weight (Mn) of at least 1000 and advan-: -::

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:::~ . , -. . . , , ~

lV45z7~;
tageously comprises between 0.05 to 4.0 weight percent of the mixture. The flow control age~t has a glass transi-tion temperature at least 20C. below the glass transition temperature of the mixture's copolymer.
One group of suitable flow control agents are acrylic polymers. Preferred acrylic polymers which may be used for the flow control agent are polylauryl acrylate, polybutyl acrylate, poly (2-ethylhexyl acrylate), poly-lauryl methacrylate and polyisodecyl methacrylate.
The flow control agent may also be a fluorinated polymer having a surface tension, at the baking tempera-`` ture of the powder, lower than that of the copolymer ~ ' ? utilized in the mixture. Preferred flow control agents, if the agent is a fluorinated polymer are esters of polyethyl-eneglycol or polypropyleneglycol and fluorinated fatty acids. For example, an ester of polyethyleneglycol of ., molecular weight of over 2500 and perfluoro octanoic acid ;, is a useful flow control agent. Polymeric siloxanes of `~ molecular weight of over 1000 (advantageously 1000 to .- 20 20,000) may also be used, e.g., polydimethyl siloxane or ~1 polymethylphenyl siloxane. -~
A coating composition formed in accordance with the teachings of this invention may include a small eight percent of a catalyst in order to increase the crosslink-ing rate of the powder coating composition at the baking - temperature thereof. Baking temperatures will ordinarily u be in the range of 130 to 200C. and the catalyst should produce a gel time for the powder coating composition at the baking temperature to be used which is at least 1 minute but no greater than 20 minutes. This gel time is .

~045Z7~;
preferably in the range of l t~ 12 minutes and most prefer-ably between about 2 and about 8 minutes at the baking temperature.
Some catalysts which are suitable for use in the powder coating compositions include tetraalkylammonium salts, imidazole type catalyst, tertiary amines and metal salts of organic carboxylic acids. The tetraalkylammonium salt catalysts include the following: tetrabutyl ammonium 5 chloride (bromide or iodide), tetraethyl ammonium chloride . ., . ~
(bromide or iodide), trimethylbenzylammonium chloride, dodecyl dimethyl (2-phenoxyethyl) ammonium bromide, di-ethyl (2-hydroxy ethyl) methyl ammonium bromide. Suitable $ ~
catalysts of the imidazole type include: 2-methyl-4-ethyl -~ -imidazole, 2-methyl imidazole, imidazole, 2 - ~(N-benzyl-... .
anilino) methylJ - 2 - imidazoline phosphate, and 2- benzyl

- 2 - imidazoline hydrochloride~ Suitable tertiary amine ~` catalysts for the powder coating compositions of this .j .
~! invention include: triethylenediamine, N,N - diethylcy-clohexylamine, and N-methyl morpholine. The metal salts of organic carboxylic acid which are catalysts for the powder :.,,j coatings of this invention include, but are not limited to: stannous octoate, zinc naphthenate, cobalt naphthenate, ~', zinc octoate, stannous 2 - ethylhexoate, phenylmercuric propionate, lead neodecanoate, dibutyl tin dilaurate and , . . .
lithium benzoate.
~ . :
The catalyst used in an individual powder coat-ing composition is generally solid at room temperature and has a melting point of from 50~C. to 200C.
' `' .

.'7 '.~, .', '~ _ 9 _ .' ~V02 l Conventlonal non-metallic and metallic plgments can 2 be u~ed wlth the~e powder coating compositions. ~uch are ~; 3 conventionally employed in an amount such as to constltute 4 between about 6 and about 35 welght percent Or the total mlxture dependlng on the plgment selected and the glos~
6 required ~or the baked ¢oatlng.
7 Slnce lndlvldual powder coatlng compositlons of this 8 lnventlon ~an be applled to an artlcle to be palnted by 9 electrostatlc methods, one may deslre to lnclude a small welght percentage o~ an antlstatlc agent ln such composltlon~. In 11 partlcular, the antistatlc a~ent ls lncluded ln a range from 12 0.05 weight percent Or the total powder composltlon. Suitable 13 antlstatlc agents lnolude, Dut are not llmlted to, tetraalkylam-14 monlum salts a~ dlscussed prevlou~ly and whlch also serve as catalysts. Other sultable antlstatlc agents lnclude: alkyl-. ;~ .
; 16 poly (ethyleneoxy) phosphate or alkylauryl poly (ethyleneoxy) ~; 17 phosphate; polyethylenelmlne, poly (2-vlnyl pyrollldone), i .~
m 18 pyrldlnlum chlorlde, poly (vlnyl pyrldlum chlorlde), polyvlnyl l9 alcohol or lnorganlc salts.
A plastlclzer may be used ln a powder coatln~
... ..
21 composltion Or thls lnventlon lr deslred. The type o~ plasti-22 cizers used very orten lnclude adlpates, phosphates, phthalates, 23 sebacates, polyesters derlved rrom adlplc acld or azelalc acld, 24 and epoxy or epoxldlzed plastlclzers. Some of these plastl-clzers are: dihexyl adlpate, dilsooctyl adlpate, dicyclo-26 hexyl adlpate, triphenylphosphate, trlcresylphosphate, trlbutyl-27 phosphate, dlbutylphthalate, dloctylphthalate, butyl octyl 28 phthalate, dloctyl sebacate, butyl benzyl sebacate, dlbenzyl 29 sebacate, ~utanedlol - 1,4 - dl~lycldyl ether, dlglycldyl ether o~ blsphenol A and lts polymers and ce~lulose acetate :.-:, , - ~. . .

~ STV02 10~5Z76 1 butyrate, 2 Havlng descrlbed the varlous materlals whlch are

3 employed ln rormulatlng the powder coating compo~ltlons Or thi~

4 inventio,n, a plurallty Or example~ are herelnafter ~et forth to lllustrate varlous lndlvldual powder coating compositions.
6 Illu~trated copolymers vary ln molecular welght rrom about 1500 7 to about 15,000.
' 8 ~xam~le 1 ' , 9 An epoxy-runctlonal, amlde-functlonal copolymer 19 prepared rrom the below llsted components ln the manner ; 11 herelnarter des¢rlbed:
; Percent by Weight ,~ 12 ReactantsAmounts~ ~rms.pr Total Reactants , 13 ~lycldyl methacrylate225.~ 15 14 methacrylamlde 75.0 5 . ., butyl methacrylate 600.0 40 16 styrene 75.0 5 ,;~- 17 methyl methacrylate 525.~ 35 ~' 18 The above mentloned monomers are admlxed ln the 19 proportlons above set rorth and 70.0 grams (4.5% based on comblned welghts Or reactants) Or 2,2' - azobls - (2-methyl - 21 proplonltrlle), herelnarter called AIBN, are added to the ''~- 22 monomer mlxture. The solutlon 19 added dropwlse over a ,- 23 3 hour perlod lnto 1500 ml. toluene at 100 - 108C. under 24 nltrogen atmosphere. Then 0.4 grams Or AIBN dl~qolved ln ~ 25 10 ml. Or acetone are added over 1/2 hour perlod and rerluxlng -,', 26 18 contlnued for 2 addltlonal hours.
.;
,, 27 The toluene-polymer solutlon ls dlluted ln 1500 ,) 28 ml. acetone and coagulated ln 16 llters Or hexane. The whlte ,, 29 powder 18 drled ln a vacuum oven at 55~C. ~or 24 hours. Thls :

- ~045Z76 copolymer has molecular weight - MW/Mn = 6750/34Q0 and the molecular weight per epoxy group, WPE, is 1068.
The prepolymer in the amount of 47.0 grams is ball-milled with 2.5 grams of 12-hydroxy stearic acid, 6.2 grams of poly (azelaic anydride), 0.45 grams of poly (2-ethylhexyl acrylate) of Mn = 9000, 5.5 grams of titanium dioxide and 4.5 grams of Ferrite yellow for 5 - lO hours.
The fine powder mixture is mill-rolled for 15 minutes at lO0 C. or extruded with a twin screw extruder. The `. ';!
~ lO resulting melt is granulated and pulverized to particles !
i of lO - 50 micron range.

The resulting powder obtained in this manner ' exhibits excellent flowability and is sprayed electrostati-cally on a grounded steel panel by using electrostatic : ~ :
powder spray gun operating at 50 KV charging voltage.
After deposition of the powder, the panel is baked at 300F. ' for 30 minutes.
~ The glossy coating obtained on the panel exhibits .`7 good adhesion to primed or unprimed steel panels, hardness j 20 and flexibility. This coating applied to other substrates `~ such as glass, brass, zinc, aluminum, copper and bronze ~ also demonstrates good adhesion. The coating obtained is : .
not soluble in gasoline, xylene, methyl ethyl ketone and `
. .. .
' tolue~e.
. ~

~l Example 2 . - , ~ The procedure of Example l is repeated. The same ? copolymer (MW/Mn = 6750/3400, WPE = 1068) is used in the preparation of a second powder coating composition. Here, 47.0 grams of this copolymer are combined with the follow-.. . .
~ 30 ing components: `
.~ .

. .
.

,.;
poly (azelaic anhydride) 7.0 grams 1 2 - hydroxystearic acid 1.5 titanium dioxide 5.5 "
Ferrite yellow 4.5 "
. "
poly (lauryl acrylate) - Mn=8000 0.45 " ~ -` All components are ball-milled for four hours and ' mill-rolled for 15 minutes at 105C. The material is granu-', lated and pulverized to particle size range of 10-50 microns.

On melting, this powder levels ~ery well and gelled in 8 minutes at 300F.

Cured coatings of this powder on steel panels, ~, i.e., deposited and cured according to the procedure of .. i; .
Example 1, exhibit excellent appearance. They exhibit high impact strength. Their solvent resistance in the solvents heretofore mentioned in Example 1 is very good.
Example 3 ~ -The copolymer of Example 1 is used in the formula-tion of another powder coating composition. Forty-seven (47.0) grams of this copolymer are combined with the follow-ing chemicals:
poly (azelaic anhydride) 5.0 grams r 12 - hydroxystearic acid 5.0 "

~ - titanium dioxide 5.5 "
`' Ferrite yellow 4.5 "
~ poly (~utyl acrylate - Mn=9000 0.5 "
.
, tetrabutyl ammonium chloride 0.04 "
The mixture is processed as in Example 1 and converted to a powder of correct particle size. Then it is sprayed on grounded steel panels and cured at 300F. for 20 minutes.

, ' - .

~ TVi~2 104S'~
l ~rhe cured coatlng 1~ glossy and smooth. The adhesion 2 and rever~e lmpact propertie~ Or the~e coatlngs are good as are .. 3 their reslstance to the organlc solvents mentioned in Example l.
4Example 4 5An epoxy-runctional and amide-functlonal copolymer ls 6 prepared ~rom the following materials:
Percent ~y Welght 7 Reactants Gramso~ Total Reactantæ
' 8 glycldyl methacrylate 20.0 lO.0 ., 9 methacrylamlde lO.0 5.0 butyl methacrylate 90.0 45 ll methyl methacrylate 70.0 35 12 styrene . lO.0 5 13To this mlxture are added lO grams Or AIBN (5% by 14 welght Or reactants). ri'he polymerlzatlon and lsolatlon of the .:, 15polymer i8 carried out as ln ~xample l. The molecular weight .~.,~ .
~a~ 16o~ thls copolymer 18 determined to be MW/Mn ~ 5860/3350 and lts 17 glass transltion temperature (T~j 18 53C.
- 18Forty seven (47.0) grams Or thls copolymer are .. ~ l9- comblned wlth the rollowlng materlals:
. , .~ ?Q poly (azelaic anhydrlde) 5.0 grams i~ 21 10-hydroxyoctadecanolc acld 5.~ "
::J
22 tltanlum dloxlde 6.0 23 Ferrlte yellow ~.o "
24 poly (lsododecyl methacrylate) o.6 , 25 tetrabutyl ammonlum iodide 0.07 "
., 26 The mixture o~ all Or these components iB ball-mllled :~ 27 for 5 hours. '~hen it 18 comblned wlth acetone-methylene chlorlde `l 28 solvent (l:l by volume) and ball-mllled ror another 5 hours.
~, 2g A~ter ev~poratlon o~ the qolvent and granulatlon Or the powder to a partlcle slze range Or lO - 50 microns, ~rounded steel panels ..~

, , .
. -14-"r : ' : , ' S'l'~TO. 10~527 1 are sprayed wlth thl~ powder ancl cured at 300F. ror 30 mlnutes.
2 These coatlngs demonstrate excellent gloss and surrace æmoothnesæ.
3 l~xample 5 4 An epoxy-~unctional and amlde-functlonal copolymer

5 1~ prepared rrom the Sollowlng materlals:
Percent By ~leight ; 6 Reactants Gramsof l~otal Reactants 7 glycldyl methacrylate 40.0 20.0 8 methacrylamide 4.0 2.0 9 butyl methacrylate 80.0 40.0 methyl methacrylate 66.o 33.0 11 styrene 10.0 5 o ~; 12 Fourteen tl4) gramq Or AIBN are added to the monomer 13 mixture. 'i'he polymerlzatlon and isolatlon Or the polymer are ~ 14 carrled out uqlng the 3ame procedures used ln Example 1.
1 15 Forty-seven (47) gr~ms Or thls copolymer are combined . ~ ~
16 wlth the ~ollowlng materlals:
17 poly (sebaslc anhydrlde) 8.o grams 18 3-hydroxyoctadecanolc acld 5.0 "
19 tltanlum dloxlde 6.0 "
Ferrlte yellow 5.0 "
21 poly (2-ethylhexyl acrylate)-MIl-8500) o . 6 22 trimethyl benzyl ammQnlum chlorlde o.o6 23 ~11 Or the roregolng ingredlents are mlxed together 24 and processed ln accordance wlth the procedure Or Example 1 to obtaln a powder coatlng composltlon. lrhls powder 18 sprayed 26 on panels and cured at 300F. ror 20 mlnutes.
27 The coatlngs obtalned from thls powder exhlbits good 28 adheslon to steel, ælass, alumlnum, zlnc and bronze. It also 29 demonstrates good scratch reslstance and good re~lstance to the organlc solvents mentloned ln Example 1.

~. ..

.

... , ., ~ . , ~0~5*~6 Example 6 The epoxy-functional, admide-functional copolymer of Example l(Mw/Mn= 6750/3400, WPE = 1068) is used for the ;~i preparation of another powder coating wherein 50.0 grams of this copolymer are combined with the following ingredients:
glutaric anhydride 5.0 grams 2-hydroxy myristic 3.0 "

` polyethylene glycol perfluoro ; octanoate (M =3400) 0.7 ~ -~, 10 tetrabutyl ammonium bromide 0.05 "
~3 ` titanium dioxide 7.0 "
ultramarine blue 3.0 "
, These ingredients are mixed together and processed - in accordance with the procedure of Example 1 to obtain a - powder coating composition. This powder coating composition : "
~, is sprayed on various test panels. The coatings obtained after curing the coatings at a temperature of 300F. for 25 minutes are glos-sy and exhibit good adhesion to the panels.
Example 7 ,, .
, 20 The epoxy-functional and amide-functional copoly-` mer of Example 1 (MW/Mn=6750/3400, WPE = 1068) is employed for the preparation of this powder coating. Fifty (50.0) ~i grams of this copolymer are combined with the following , materials:
, succinic anhydride 5.2 grams i' 2-hydroxyoctadecanoic acid 3.0 "
' tetraethyl ammonium iodide 0.07 "
poly (lauryl acrylate) - (Mn=8000) 0.6 " -Titanium dioxide 6~0 "
Phthalocyanine Blue 4.5 1(~45Z71i 'he above lngredlents are mlxed together and proce~sed 2 ln accordance wlth the procedure of Example 1 to obtain a 3 powder coatln~ composltion. This powder coatlng compo~ltlon is 4 sprayed on varlous te~t panels and cured at 340F. ~or 25 minutes.
ri~he coatlngs demonstrate good adhesion and appearance.

6 Example 8

7 The procedures Or Examples 1 - 7 are repeated with

8 the slngle exceptlon that an equlmolar amount of glycidyl

9 acrylate ~ 8 substituted ~or the glycldyl methacrylate used as ~i lO a constltuent Or the epoxy-functional, amide-functional copolymer.
:,;
11 ~
12 'l'he procedures Or Examples l - 7 are repeated with ~` - 13 the slngle exceptlon that an equlmolar amount of acrylamide i8 ; 14 sub8tituted ror the methacrylamide u5ed as a constltuent of the ~ 15 epoxy-functlonal, amide-runctlonal copolymer.
'~ 16 ExamDle lO
. A _. , 17 An epoxy-runctional, amide-runctlonal copolymer ls ~ 18 produced uslng the method Or Example l and the ~ollowing ''~'7~ 19 materlals:
::
Reactants Percent by Wei~ht 21 glycldyl methacrylate 5 22 methacrylamlde lO
23 styrene 24 butyl methacrylate 40 methyl methacrylate 40 26 With these materials, AIBN ln the amount of o.8% by 27 welght Or the reactants 1~ employed.
28 Thls copolymer ln the amount Or 47.0 grams was com-2~ pounded with the rollowlng materials:

`:
: , , , ., : .
;-............................. . . .

- `

, poly (azelaic anhydride) 3.1 grams ` 10 - hydroxy stearic acid 3.3 : poly (2-ethylhexyl acrylate) 0.43 titanium dioxide 5.5 "
Ferrite yellow 4.5 "
~, The mixture is processed to the preparation of a :
~ .
~ sprayable coating material following the same procedure - used in Example 1. This material is sprayed on substrates ~, and cured as in Example 1. The coatings exhibit good .~ 10 appearance and good adhesion.
.
Example 11 1 An epoxy-functional, amide-functional copolymer ,~ having molecular weight of about 1500 prepared using the . . ,~
, method of Example 1 from the following materials:
Reactants Percent by Weight ~ glycidyl methacrylate . 14 ,~
. ~i , .
; methacrylamide 6 butyl methacrylate 40 methyl methacrylate . 40 , With these materials, there are used 7 grams of AIBN. ~ :
~ This copolymer is compounded into a coating mater-; - ial using the methods and materials af Example 1, sprayed .
upon a metal substrate as in Example 1, and cured as in ~ Example 1. In this instance, 47 grams of this copolymer are .~ used with 2.5 grams of poly (azelaic anhydride) and 2.5 ~ grams of 12 - hydroxystearic and 1 gram of stannic chloride.
, .
Example 12 An epoxy-functional, methacrylamide-functional copolymer having molecular weight of about 15,000 is pre-., !

.
:1 i. . -:: . , . . - : ' :............. . . ~ , .
,'~,1 - . ' '. . : : ~

-: 1045Z76 pared using the method of Example 1 from the following materials:
Reactants Percent by Weight . glycidyl methacrylate 8 methacrylamide 2 . butyl methacrylate 40 ' methyl methacrylate 50 With these materials, there are used 0.8 grams i........... of AIBN.
This copolymer is compounded into a coating mater~
ial using the methods and materials of Example 1, sprayed upon a metal substrate as in Example 1 and cured as in Example 1. In:this instance, 47 grams of this copolymer, :~
~ are used with 6.0 grams of poly (azelaic anhydride) and 3.0 ::~ grams of 12-hydroxystearic acid. :~
;~ Example 13 - ':
. .1 , . .
.~ The procedure of Example 1 is repeated except for : ~
,, ; - the difference that the copolymer is formed from the follow-ing materials~
~ 20 ReactantsPercent by Weight :- glycidyl methacrylate 15 ~. :
, methacrylamide 5 - ;:
.~ vinyl chloride 20 vinyl toluene 5 ~
, ethyl acrylate 5 ~ : :
~i butyl acrylate 25 ~ ~;
., methyl methacrylate 25 :
- Example 14 . j .
. ~ .
The procedure of Example 1 is repeated except for the difference that the copolymer is formed from the follow-, ing materials:
.`

-19-- .

:;.. :: .- . . .. ,. . -1045;Z76 Reactants Percent by Weight glycidyl methacrylate lS
methacrylamide 5 t-butyl styrene 5 chlorostyrene 10 . ~ .
`' acrylonitrile 5 ~i butyl methacrylate 30 .I methyl methacrylate 30 ,. Example 15 .l 10 The procedure of Examp:l.e 1 is repeated except for the difference that the copolymer is formed from the follow- ;
`~ ing materials:
~ - Reactants - Percent by Weight '.`~s1 glycidyl methacrylate 15 ~.~ methacrylamide 5 - ~
s~ hexyl acrylate . 5 I ::
2-ethylhexyl methacrylate 10 butyl acrylate 10 methyl methacrylate ~ 55 ~ 20 Example 16 ,~
The procedure of Example 1 is repeated except for . the difference that the copolymer is formed from the follow- :;
. ing materials:
Reactants Percent by We ght glycidyl methacrylate 15 ... .
methacrylamide - 5 alpha methyl styrene 5 . 2-ethylhexyl acrylate 5 vinyl acetate s methacrylonitrile 5 butyl methacrylate 20 .~ methyl methacrylate 40 .

ii -20-;:- . :- . . ~- -~ Example 17 .
The procedure of Exam~le 7 is repeated with the two exceptions that (1) an equimolar amount itaconic an-hydride is substituted for the succinic anhydride and (2) `, a functionally equivalent amount of poly (dimethyl siloxane) `~i is substituted for the poly (lauryl acrylate).

; - Example 18 .
~ The procedure of Example 7 is repeated with the -, exceptions that an equimolar amount of phthalic anhydride is substituted for the succinic anhydride and (2) a func-' tionally equivalent amount of 10-hydroxyoctadeocanoic ~' acid in place of 2-hydroxyoctadeocanoic acid.
Example 19 The procedure of Example 7 is repeated with the exception that an equimolar amount of p-chlorophthalic , anhydride is substituted for the succinic anhydride.
Example 20 ,:.~ . . .
The procedure of Example 7 is repeated with the exception that an equimolar amount of tetrahydrophthalic .

~ 20 anhydride is substituted for the succinic anhydride.

-~ Example 21 ' The procedure of Example 1 is repeated with the .~ .
1 exception that an equimolar amount of poly (adipic anhy-.. ` .
, dride) is substituted for the poly (azelaic anhydride).

-~ Example 22 ~1i The process of Example 1 is repeated with the single difference that the flow control agent, poly (2-; ethylhexyl acrylate) is employed in an amount equal to -0.05 weight percent of the powder mixture.

- ' ~s -21-:-, i~, . . .

.. -.,: ..... . - . -: ~ . -104527~
~ Example 23 ~ The process of Example 1 is repeated with the : single difference that the flow control agent, poly (2-ethylhe~yl acrylate) is employed in an amount equal to ` 1.0 weight percent of the powder mixture.
. Example 24 ~ The process of Example 1 is repeated with the - single difference that the flow control agent, poly (2-::1 ethylhexyl acrylate) is employed in an amount equal to 2.0 weight percent of the powder mixture.
. Example 25 . The process of Example 1 is repeated with the single difference that the flow control agent, poly (2~
:. ethylhexyl acrylate) is employed in an amount equal to 4.0 ~ weight percent of the powder mixture.
.~:
Many modifications of this invention will be apparent to those skilled in the art in view of this ': ~
specification. It is intended that all such modifications ~ .
' which fall within the scope of this invention be incIuded .~. 20 within the appended claims.
.. - ' ' ". ;~
.``'' ' ' .
.
l ;`'':

, , ~, .. , . , -.~

.. -22-

Claims (6)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A powder coating composition which exclusive of pigments and other non-reactive components comprises a co-reactable mixture of:
(a) a qualitatively difunctional copolymer of about 5 to about 20 weight percent of a glycidyl ester of a monoethylenically unsaturated acid, about 2 to about 10 weight percent of a monomeric, alpha-beta olefinically unsaturated amide and about 70 to about 93 weight percent of monoethylenically unsaturated monomers consisting essentially of monofunctional monomers selected from the group consisting of esters of a C1 to C8 monohydric alcohol and acrylic acid, esters of a C1 to C8 monohydric alcohol and methacrylic acid and C8 to C12 monovinyl hydrocarbons, said copolymer having a glass transition temperature in the range of 40°C to 90°C and a molecular weight (?n) in the range of 1500 to 15,000, (b) an anhydride crosslinking agent selected from the group consisting of (1) monomeric anhydrides of dicarboxylic acids and (2) polymers of monomeric anhydrides of dicarboxylic acids and present in the amount of about 0.3 to about 1.2 anhydride groups for each functional group on said copolymer, the functional groups of said copolymer being limited to epoxy groups and amide groups, and (c) a hydroxy carboxylic acid having a melting point in the range of about 40°C to about 150°C in an amount such as to provide about 0.1 to about 0.4 hydroxy groups and about 0.1 to about 0.4 carboxyl groups per functional group in said copolymer.

2. The powder coating composition of claim 1, wherein said monomeric anhydrides have melting points in the range of about 35°C to about 140°C.

3. The powder coating composition of claim l, wherein said polymers of monomeric anhydrides have molecular weight in the range of about 1000 to about 5000.

4. The powder coating composition of claim 1, wherein said copolymer has molecular weight (?n) in the range of about 2500 to about 6000.

5. The powder coating composition of claim 1, wherein said amide is acrylamide or methacrylamide.

6. The powder coating composition of claim 1, wherein said glycidyl ester is glycidyl acrylate or glycidyl methacrylate.