CA2048179A1

CA2048179A1 - Hybrid polymer, aqueous dispersions and coating composition therefrom

Info

Publication number: CA2048179A1
Application number: CA 2048179
Authority: CA
Inventors: Roelof Buter; Peter M. Postma
Original assignee: Individual
Current assignee: Akzo NV
Priority date: 1990-08-02
Filing date: 1991-07-31
Publication date: 1992-02-03
Also published as: BR9103337A; JPH04233926A

Abstract

ABSTRACT OF THE DISCLOSURE

A hybrid polymer of a core/shell structure is provided which is based upon (A) a polymer (core) of an unsaturated fatty acid group functionalized poly(epoxyester) onto which (B) at least one addition polymer-based chain (shell) has been grafted. Also provided are aqueous dispersions of these hybrid polymers and coating compositions therefrom, which coating compositions are especially suited for use as clear coatings, pigmented coatings and primers/surfaces.

Description

7 ~

HYBRID POLYMER, AQUEOUS DISPERSIONS
AND COATING COMPOSITION THEREFROM

The present application is entitled to the bene~it o~
earlier filing dates in a ~oreign country under 35 IJ.S.C. 119, based upon European Applications Serial Nos. 90202106.2, ~iled August 2, 1990, and 91200865.3, filed April 4, 1991, which are hereby incorporated by reference.

The present application is related to co pending and commonly assigned United States Patent Application Serial No.
07/661,712, filed February 27, 1991 and entitled "A~ueous Dispersions of Hybrid Polymers and Coating Compositions Containing Same."

BACKGROUND OF TH~E INVENTION

The present invention relates generally to a water-dispersibla hybrid polymer of a core/shell structure, which comprisss (A~ a polymer (core) onto which (B) at least one addition polymer-based chain (shell) has been gra~ted. The present invention also relates generally to aqueous dispersions of these hybrid polymers and coating compositions based thereon, which coating compositions are especially suitable ~or use as primer~/sur~aces, clear coatings and pigmented top coatings.

Hybrid pol~mers comprising a polymer backbone onto which at least one addition polymer-based chain has been grafted are, in a general sense, known in the art, as is their use in coating compositions. See, for example, DE-A-2304680, U.S.
3,93~,562 and U,S. 4,025,471.

Aqueous versions of such are also known. See, for example, BE 854523, EP-A-0116225, EP-A-0287144, U.S.
4,028,2~4, U.S. 4,116,901, U.S. 4,151,131, U.S. 4,212,776, .~

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~co 2238 U.S. 4,212,781, U.S. 4,285,847, U.S. 4,297,261, U.s.
4,303,565, U.S. 4,308,185, U.S. 4,443,568, U.S. ~,564,6~8, JP-A-63309516 and Bauer, Ronald S., "Recent Developments in Water Borne Epoxy Resins," Journal of Waterborne ~oatin~s, Vol. 5 (1982), pp. 5-17.

: SUMMARY OF ~HE INVENTION

A particular type of hybrid polymer has now been discovered which, when dispersed in an aqueous medium, produces stable dispersions with relatively low viscosities even at concentrations of 40 percent by weight and higher.
The hybrid polymers themselves possess a relatively low acid number, which is comparable to polymers used in organic solvents.

Further, aqueous coating compositions based upon these aqueous dispersions may be formulated at quite high solids contents, and coating compositions can be formulated from these aqueous dispersions to result in films displaying a good combination of physical and mechanical properties such as chemical, water and acid resistance, as well as good durability~

Such advantageous hybrid polymers, as well as a~ueous dispersions and coating composition~ there~rom, are neither ~pecifically known from nor suggested by the aforementioned prior art.
. .
:~ 25 In accordance with the present invention, there i9 provided a hybrld polymer which comprises (A) a polymer (core) onto which (B) at least one addition polymer-based chain (ahell) haa been graieed, wherein:

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i. the polymer (A) comprises an unsaturated ~atty acid group ~unctionalized poly(epoxyester), which i5 the reaction product of (1) an epoxy-terminated poly(epoxyester) and (2) an unsaturated fatty acid component, at least a -~ portion of which comprisas an unsaturated fatty acid with conjugated double bonds;
ii. the addition polymer based chain (B) has an acid number of from about 20 to about 100; and iii. the at least one addition polymer-based chain (B) is grafted onto polymer (A) via the addition polymerization of ~ree-radically pol~merizable monomers in the presence of the unsaturated ~atty acid group functionalized poly(epoxyester).
It is pre~erred that the hybrid polymer comprises (A) from about 40 weight percent to about 90 weight percent o~ the polymer (core) and (B~ from about 10 weight percent to about 60 weight percent of the addition polymer-based chains (shell), based upon the total weight of the hybrid polymer, and preferably consists eæsentially of the polymer (A) and the addition polymer-based chain (B) as recited above~ Within these boundaries it has been ~ound that the hybrid polymers possess the best mixture o~ advantageous properties from the individual aomponents. Advantageous properties o~
; poly(epoxyesters) include, for example, good adhesion to many substrates, good mechanical resistance and a good balance o~
hardness and ~lexibility. Advantageous properties of addition polymers include, for example, good chemical resistance.
:
The hybrid polymers in accordance with the present invention are readily water dispersible upon at least partial neutralization of the acid groups of the addition polymer-~ based chains (B). Aqueous dispersion o~ such are produced by `; 3 : :

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at least partially neutralizing the acid groups and dispersing the so-neutralized hybrid polymers in an aqueous medium.

The aqueous dispersions of the hybrid polymers in accordance with the present invention are suitable for a variety of uses but especially as aqueous coating compositions. They are especially suited ~or use as primers/surfacersl clear coatings and pigmented top coatings because they can be formulated to result in films possessing a desirable combination of chemical, water and acid resistance, and excellent durability re~uired for the ultimate end use.
.;
These and other features and advantages of the present invention will be more readily understood by those skilled in the art from a reading of the ~ollowing detailed description with reference to the specific examples contained therein~

DE?AILED DESCRIPTION OF THE PREFERRED ~MBODIMENTS
~' As indicated earlier, the present invention concerns a particular water-dispersible hybrid polymer, a~ueous dispersion of such hybrid polymer and coating composition ~ based thereon.

- 20 The hybrid polymer, in its o~erall concept, comprises (A) a polymer (aore) onto which (B) at least one addition polymer-based chain (shell) has been grafted via the addition polymerization of free-radically polymerizable monomers in the presence of the polymer (core).

The polymer (A) is an unsaturated fatty acid group functionalized poly(epoxyester) which is the reaction product of (1) an epoxy-terminated poly(epoxyester) and 7 r~
~CO 2238 (2) an unsaturated fatty acid component, at least a portion o~ which comprises an unsaturated fatty acid with conjugated double bonds.
The epoxy-terminated poly(epoxyester) preferably comprises the reaction product of n moles of a bisepoxida having a number average molecular weight (Mn) in the range of from ahout 150 to about 2000, and n-l moles of a dicarboxylic acid having 4-40 carbons atoms, wherein n - 2-10. The Mn of th~ resulting poly~epoxyester) preferably range~ from about 400 to about 20,000, more preferably ~rom about 2000 to about 20,000.

; As suitable bisepoxiqes may be mentioned a wide variety ~ 15 of aliphatis, aromatic, araliphatic and cycloaliphatic : bisepoxides as well as mixtures thereof. A number of suitable specific examples may be found by refere~ce to Epoxy Reslns -Chemistry and Technoloqy, 2d ed., Mossel Dekker Inc., New York ~; (1988), pages 212-31, which is specifically incorporated by reference herein for all purposes.

As pre~erred examples may be mentioned the diglycldyl ~; ethers of bi phenol A; epoxy oligomers from epichlorohydrin ~ and bisphenol A having oxirane end group~ and an Mn in the : range of from about 300 to about 2000; epoxy oliyomers ~rom epichlorohydrin and hydrogenated bisphenol A having oxirane ; end groups and an Mn in the range o~ from about 300 to about :~ 2000; 1,3-bi~2,3-epoxyprop~l-oxy) benzene; 1,4-butanediol ; diglycidyl ether; a diglycidyl ether of polypropylene glycol;
: a diglycidyl ether of dimerized linoleic acid;
. 30 epoxydicyclopentyl phenyl glycidyl ether; bis~2,3-: epoxycyclopentyl) ether, bis(2,3-epoxy-6-methylcyclohexylmethyl) adipate; 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate; 3,4-epoxy-6-~' .
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. 7~3 methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexane carboxylate, and dicyclopentadiene dioxide.

When the hybrid polymers are utilized in primer/surfacer applications, the aromatic bisepoxides (e.g., those based upon bisphenol A~ are preferred because o~ their excellent corrosion resistance. Particularly preferred of these are the aforementioned diglycidyl ethers of bisphenol A, and epoxy oligomers from epichlorohydrin and bisphenol A.

When utilized in clear coating and/or pigmented top coating applica~ions, however, the cycloaliphatic bisepoxides (including those based upon hydrogenated bisphenol A) are preferred because of their excellent ultraviolet light -~; resistance.
:
As examples of preferred dicarboxylic acids having from 4 to about 40 carbon atoms may be mentioned adipic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, hexahydrophthalic a~id, succinic acid, sebacia acid, dodecane dicarboxylia acid, azelaic acid and dimeriz2d fatty acids. Especially preferred are those having ~rom 10 to 40 carbon atoms, partiaularly the dimerized fatty acids haviny from 18 to 36 carbon atoms.

The epoxy-texminated poly~epoxyester) is unsaturated fatty acid group functionalized through the reaction of at least a portion of the epoxy groups with one or more unsaturated fatty acids (unsaturated fatty acid component), at least a portion of which include con~ugated double bonds.

As examples of suitable unsaturated fatty acids may be mentioned a wide variety of mono- and polyunsaturated fatty acids, and preferably those having from about 12 to 26 carbon atoms. As specific suitable examples may be mentioned mono-:. ~
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unsaturated fatty acids such as myristoleic acid, palmitoleicacid, oleic acid, gadoleic acid, erucic acid and ricinoleic acid; di-unsaturated fatty acids such as linoleic acid; tri-unsaturated fatty acids suchlas linolenic acid, eleostearic acid and licanic acid; tetra-unsaturated fatty acids such as arachidonic acid, penta-unsaturated fatty acids such as clupanodonic acid; and other unsaturated fatty acids pr~pared from animal or vegetable oils. Normally, natural fatty acids will be utilized which comprise at least 30 percent of the - 10 above-mentioned fatty acids or mixtures thereof.
:.
As mentioned above, the unsaturated fatty acid component mu~t comprise at least a portion, preferably at least 10 mole percent, and especially ak lea~t 30 mole percent, of a fatty acid with conjugated double bonds, for example, conjugated linoleic acid. The actual amount of conjugated double bond-containing fatty acid will vary depending primarily upon the monomers and initiators used for the grafting of the addition polymer-based chains (B) onto the polymer (A), and also upon the ultimate use of the hybrid polymer.

In general, if more reactive monomer~ (e.g., acrylic monomers~ and initiators are u~ed, it is pre~erred khat the fatty acid component aomprise from 10-80 mole percent, more preferably 30 60 mole percent, of a fatty acid with conjugated double bonds. Under the most reaative conditions, mor~ than 80 mole percent fatty acid with conjugated double bonds can result in gelation. On the other hand, if less reactive monomers (e.g., methacrylic monomers) are utilized, it is preferred that the fatty acid component comprise from about 5 to lOO mole percent of a fatty acid with conjugated double bonds.

When the hybrid polymer is ultimately utilized in clear coating and/or pigmented top coating applications, the .' ; , ': .','' '` ';:

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unsaturated fatty acid should comprise at least 30 mole percent of the fatty acid with conjugated double bonds. In addition, if the more reactive monomers and initiators are used, it is preferred that the fatty acid component comprise 30-50 mole percent fatty acid with conjugated double bonds; if the less reactive monomers and initiators are used, it i5 preferred that the fatty acid component comprise 50-65 mole percent fatty acid with conjugated double bonds.

One skilled in the art, based upon these general guidelines and general knowledge, can readily and appropriately choose the desired unsaturated fatty acid component.

A portion of the unsaturated fatty acid component may be replaced with a monofunctional compound of the general formula ~ 15 (I) ::
: ~ R ~ X (I) wherein R represents a hydrocarbon group having from 1 to 40 carbon atoms, more preferably an alkyl, aralkyl, aryl or cycloalkyl group having from 1 to about 24 carbon atoms; and X
represents a functional group which is reactive with an epoxy group, preferably an amino or carboxyl group, and especially a carboxyl group.
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Especially preferred monofunctional compounds are the monocarboxylic acids. As suitable monocarboxylic acids may be mentioned a wide vari~ty of aromatic, araliphatic, aliphatic and cycloaliphatic mono-carboxylic acids, pre~erably having from 2 to 24 carbon akoms. As particularly preferred examples may be mentioned pivalic acid, propionic acid, benæoic acid and stearic acid.

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The unsaturated fatty acid is reacted with the epoxy-terminated poly(epoxyester) in an equivalence ratio of carboxyl groups/epoxy groups of at least about 1:4, more preferably at least about 1:2. The combination of the unsaturated fatty acid and monofunctional compound is preferably reacted in an equivalence ratio of carboxyl ~ X
groups/epoxy groups of from about 1:4 to about 1:1, more preferably about 1:2 to about 1:1, and especially about 1:1 so as to result in essentially no residual epoxy functionality.

The unsa~urated fat~y acid group functionalized poly(epoxyester) may be produced in a conventional manner by reacting the bisepoxide, dicarboxylic acid, unsaturated fatty acid component and optional mono-functional compound in the amounts described above.

Preferably, the reaction should take place in an organic solvent (10 to 30 weight percent) at a temperature of between about 60C and about 2000C. The organic solvent Por the ~; reaction should be water miscible. As suitable examples may be mentioned glycol ethers and propyleneglycol ethers, such as methoxypropanol, butoxyethanol, isopropoxypropanol, propoxypropanol, diethylene glycol dimethylether and N-methyl pyrrolidone. Small amounts of non-water miscible organic solvents may also be utilized, such as ethyl methyl ketone and methyl isobutyl ketone.

A catalyst may also be utilized for the reaction between the epoxy groupa, and the carboxyl and other ~unctional groups. As suitable examples may be mentioned acid catalysts such as p-toluene sulfonic acid; basic amine, ammonium and phosphonium catalysts such as t~tra-methylammonium chloride, benzyltrimethylammonium methoxide and triphenylbsnzyl phosphonium chloride; and other well-known catalysts such as .

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CrtIII)2-ethylhexanoate, zinc chloride and zinc acetylacetonate.

The hybrid polymer is formed by the addition polymerization o~ free-radically polymerizable monomers in the presence o~ the above-described unsaturated fatty acid group functionalized poly(epoxyester). It i~ believed that the addition polymer-based chains are thereby grafted onto the poly(epoxyester) backbone via the unsaturated functionality resulting from the unsaturated fatty acid.
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- 10 A wide variety of free-radically polymerizable monomers are suitable ~or use in producing the addition polymer-based chains. As specific examples may be mentioned ethylenically ~; ; unsaturated monocarboxylic acids, such as (meth)acrylic acid :; and crotonic acid; (cyclo)alkyl(meth)acrylates with 1 to about : 15 12 carbon atoms in the (cyclo)alkyl group, such as ~ methyl(meth)acrylate, ethyl(meth)acrylate, :~ propyl(meth)acrylate, isopropyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, :~ octyl(meth)acrylate, isobornyl(meth)acrylate, 20 dodecyl(meth)acrylate and cyclohexyl(meth)acrylate;
dicarboxylia acids such as maleic acid (and anhydride), umaria acid and itaconia acid (and anhydride); the : (cyclo)alkyleskers o~ such dicarboxylic acids with 1 to about :: ~ 12 carbon atoms in the (cyclo)alkyl groups, such as d~methyl maleate, diethyl maleate, diethyl ~umarate, dipropyl maleate, dibutyl maleate, dibutyl ~umarate, 2-ethylhexyl maleate, ~: 2-ethylhexyl fumarate, octyl maleate, isobornyl maleate~
~; dodecyl maleate and cyclohexyl maleate; (meth)acrylates with ether groups, such as 2-methoxy-ethylmethacrylate, 2-ethoxy-ethylmethacrylate and 3-methoxy--propylmethacrylate;
; hydroxyalkyl(meth)acrylates, such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, ~:` 4-hydroxybutylacrylate, 6-hydroxyhexylacrylate, ~` .
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p-hydroxycyclohexyl(meth)acrylate, hydroxypolyethyleneglycol(meth)acrylates, hydroxypolypropyleneglycol(meth)acrylates and the alkoxy derivative thereof; monovinyl aromatic compounds, such as styrene, vinyltoluene, ~-methylstyrene and vinylnaphthalene;
other substituted (meth)acrylic compounds, such as (meth)acrylamide, (meth)acrylonitrile, N-methylol(meth)acrylamide and N-alkyl(meth)acrylamides; and other monounsaturated compounds such as vinyl chloride, vinyl acetate, vinyl propionate and vinylpyrrolidone.

Preferrad monomer mixtures for use in producing the addition polymer-based chains are those disclosed in EP-B-0000601 and U.S. 4,245,074, which are incorporated by reference herein for all purposes. As a first specific example may be mentioned the ~ollowing monomer mixture:
35 55 mol percent of styrene and/or ~-methylstyrene;
20-50 mol percent of a compound of the general formula (II) H2C = C - C - 0 - CH2 - CH - CH2 - O - C - R2 : 20 Rl O OH O

wherein R1 i8 an H atom or a methyl group, and R2 is an alkyl group with ~-10 carbon atoms; and 0 to 30 mol percant o~ another monoethylenically unsaturated compound such as described above.

As a second specific example may be mentioned the following monomer mixture:
35 to 55 mol percent of styrene and/or ~ methyl styrene;
20 to 50 mol percent of acrylic acid and/or methacrylic acid; and 0 to 30 mol percent of another monoethylencially unsaturated compound such as described above, `
' : ~4~

wherein the reaction product during or a~ter the polymerization is reacted with a glycidyl ester of a carboxylic acid, having the general formula (III) \ / " (III) O O

wherein R2 is as defined above.
The particular monomers and/or monomer mixtures should be chosen in a manner and in an amount so as to result in an 10 addition polymer-based chain having an acid number of between about 20 and about 100 (mg KOX/g). It has been genera~ly found that stable dispersions cannot readily be produced when the acid number of the addition polymer-based chains is below about 20, and when the acid number is above about 100 the 15 water-resistance becomes unacceptable. It is especially preferred that the acid number should be in the range of from about 30 to about 80.

The monomera and/or monomer mixtures should also be chosen in a manner and in an amount so as to result in the 20 hybrid polymer comprising:
A) ~rom about 40 weight percent to about 90 weight peraent o~ the polymer (core) and B) ~rom about 10 weight percent to about 60 weight percent o~ the addition pol~mer-based chains :~ 25 (~hell), based upon the total weight of the hybrid polymer. As mentioned earlier, within these boundaries it has been ~ound that the hybrid polymers possess the best mixture o~
advantageous properties from the in~ividual components.

Of course, the particular choice of monomers and/or monomers mixtures will also depend on a wide variety of other faotors ~uch a~, for example, the particular end use of the .
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h~brid polymer. These and other factors will be appreciated by one skilled in the art, who can further adjust the choice of monomers accordingly.

The copolymerization of the ethylenically unsaturated monomers in the presence of the unsaturated fatty acid group functionalized poly~epoxyester) is in general conducted under an inert (e.g., nitrogen) atmosphere and in the presence of a radical initiator. The polymerization temperature may generally range ~rom about 60C to about 200C, and preferably from about 100C to about 160C.

As suitable radical initiators may be mentioned dibenzoyl peroxide, dicumyl peroxide, methylethyl ketone peroxide, cumene hydroperoxide, tert-butyloxy-2~ethylhexanoate, tert-butylperbenzoate, tert-~utylcumyl peroxide, di-tert~butylperoxy-3,5,ei-trimethylcyclohexane and 1,3-bis(tert-butyl~peroxyisopropylbenzene. Mixtures of the above axe also ~uitable. In general are the radi~al initiators utilized in amounts o~ ~rom about 0.05 weight percent to about 10 weight percent, and preferably from about 1 weight percent to about 5 weight percent, based upon the total weight of the monomer mixture.

The ~o-produaed hybrid polymers are readily dispersible in an aqueous medium upon at least partial neutralization o~
- the carboxyl groups o~ the addikion polymer-based chains.
Suitable neutralizing agents for carboxyl groups include a wide variety of organic and inorganic bases, for example, tertiary amines. The pre~erred degree of neutralization ~- ranges from about 50 percent to about 130 percent on an e~uivalent basis.

Ater neutralization, the hybrid polymers may readily be dispersed in an aqueous medium by convantional means, ,~
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preferably at elevated temperatures from about 50C to about lOO~C. When hybrid polymers according to the present invention are utilized, in many cases stable aqueous dispersions of 40 weight percent and even higher may be produced.

Typically, the aqueous dispersions in accordance with the present invention will comprise a solids content of from about 30 weight percent to about 60 weight percent, and preferably in the range o~ from about 35 weiyht percent to about 55 weight percent.

As indicated earlier, a preferred use of these aqueous dispersions is in the ~ormulation of coating compositions.
When so utilized, the coating compositions may also contain a curing agent ~or the hydroxyl groups of the hybrid polymer.

; 15 As suitable hydroxyl group-reactive curing agents may generally be mentioned N-methylol and/or N-methylol ether-containing animoplasts. Especially favorable results can be obtained by using a methylol melamine having 4 to 6 meth~lol groups per molecule, with at least three of the methylol groups being etherified with methanol, butanol and/or a methanol or butanol condensation product o~ formaldehyde and N,N'-ethylene dlurea. Other suitable curing agents include water dispersible blocked isocyanates, such as those blocked with methylethylketoxime, and isocyanate group~containing adducts o~ a polyisocyanate and a hydroxycarboxylic acid, for instance, dimethylpropionic acid.

~ he curing agents reacting with the hydroxyl groups are generally utilized in amounts such that the ratlo of the hydroxyl groups o~ the hybrid polymer to the reactive groupe of the curing agent is in the range of from about 0.7 to about 1.5.

Depending upon the field of application, the coating compositions may also contain a variety o~ other additives common to the paint industry such as pigments, coloring agents, pigment dispersing agents, and thixotropic and other rheological agents. The coating may, if desired, also contain accelerators for the curing reaction, for example, acid compounds such as p-toluene sulfonic acid and blocked derivatives thereof.

The coating compositions may be applied onto any number of well-known substrates such as wood, synthetic materials and metals. Suitable application methods include rolling, spraying, brushing, sprinkling, dipping and electrostaic spraying.

The coating compositions may be dried and cured under a variety of conditions, for example, at ambient temperatures.
Accelerated curing may also be accomplished by baking at elevated temperature of generally from about lOO~C to 160C
for from about 20 to 60 minutes.

As mentioned earlier, these coatiny compo~itions are suitable for use in a wide variety o~ applications. They are, ~ however, especially suited for use as primers/sur~aces, clear ; coatings and pigmenked top coatlngs because they can be formulated to result in films possessing a desirable combination of chemical, water and acid resistance, and excellent durability re~uixed for the ultimate end use.

, The foregoing more general discussion of the present invention will be further illustrated by the following specific examples.

. ~ .

~ ç~ 7 9 EXAMPLES

:~:. Preparation of Dispersions In the ~ollowing Examples 1 to 15, a number o~ stable : aqueous polymer dispersions were prepared in accordance with the present invention. Various properties of these dispersions were measured, and the results are presented below in Table I.

In these examples, the mean particle size of the dispersions was determined b~ dynamic light scattering, the dispersions being diluted with water to a solids content of about 0.1 percent by weight.

The viscosity of the dispersions was determined with the aid of a Brookfield viscometer.

The solids content of the dispersions was determined in accordance with ASTM method 1644-59, with heating at 130C
over a period o~ 30 minutes.

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~Y~ 3~ g EXAMPLE l In a 2 liter reaction flask fitted with a stirrer, a thermome~er, a reflux condenser and a dropping funnel were homogeneously mixed: ~
52.4 g of a dimerized fatty acid (commercially available under the trade designation Pripol 1013 from Unilever), 37.2 g of sebacic acid, 138.0 g of a first epoxy resin (a diglycidyl ether of bisphenol A commercially available under the trade designation Epikote 828 from Shell~, 52.4 g of a first unsaturated fatty acid (containing 65%
conjugated linolsic acid, commercially available under the trade designation Nouracid DE-656 from Akzo), 60.0 g oP l-methoxy propanol-2 and 0.3 g of Cr(III~ 2-ethylhexanoate.

The dropping funnel was filled with a ~omogeneous mixture of:
: 20 .~0.4 g of styrene, 20.7 g o~ butyl methacrylate, 25.1 g of methacrylia acid, 40.2 g oP the ylyaidyl ester of l,l-cllmethyl-1-heptane carboxylic acid (commercially available under the : 25 trade designation Cardura E Prom Shell), 3.6 g of tert-butylperbenzoate and 40.1 g of l-me~hoxy propanol-2.

~ After ventilating, the reaction flask and dropping Punnel - were brought under a nitrogen atmosphere. The con~ents of the reaction flask were then heated to reflux temperature (135C
to 145C) and maintained at that temperature for 3 hours, after whlch the temperature of the reaction flask was brought .
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to 125C, the contents of the dropping funnel added, and the reaction mixture temperature maintained at 125C for another four hours.

The contents of the reaction flask were then cooled to 100C and 11.7 g of N,N-dimethylethanolamine added after which, over a period of two hours, 441 g of demineralized water were also added.

EXAMPL~ 2 Example 1 was repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
56.2 g of the dimerized fatty acid, 39.8 g of sebacic acid, 147.8 g of the first epoxy resin, 56.2 g of the first un~aturated fatty acid, 65.0 g of l-methoxy propanol-2 and 0.3 g of Cr(III) 2-ethylhexanoate.

The dropping funnel was filled with a homogeneous mixture of:
; 20 25.3 g o~ styrene, 17.3 g of butyl methacrylate, 20.9 g of methacrylic acid, 33.5 g of the glycidyl ester, 3.0 g o~ tert-butylperbenzoate, and : 25 35.1 g of l-methoxy propanol-2.

After the cooling of the contents of the reaction flask to lOO~C, 9.7 g of N,N-dimethylethanolamine were added after ; which, over a period o~ two hours, 399.7 g of demineralized water were also added.

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2 ~! L/~ 7 9 Example 1 was repeated in its entirety except for the following.
In the reaction ~lask were homogeneously mixed:
92.9 g of the dimerized fatty acid, 61.1 g of the first epoxy resin, 77.4 g of a second epoxy resin ~a diglycidyl ether of bisphenol A commercially available under the trade designation Epikote 1001 from Shell), 23.2 g of the first unsaturated fatty acid, 25.4 g of a second unsaturated fatty acid (containing 87%
ricinoleic acid, commercially available under the trade designation Nouracid CS-80 from Akzo), 60.0 g of 1 methoxy propanol-2 and ~:~ 15 0.3 g of Cr(III) 2-ethylhexanoate.
';
. The dropping funnel was filled with a homogeneous mixture :: of:
~ 29.05 g o~ styrene, ; 7.0 g o~ methyl methacrylate, ~ 20 25~15 g of aarylic acid, :l 56.7 g of the glycidyl ester, 2.1 g o~ dicumyl peroxide, and 40.1 g of l-methoxy propanol-~.

; The polymexization of the acrylic monomers was carried ~ 25 out at 130C for 4 hours.
; ~ After the cooling of ~he contents of the reaction flask :~ to 100C, 10.9 g of N,N-dimethylethanolamine were added after which, over a period of two hours, 542 g of demineralized water were also added.

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EX~MPLE 4 Example 3 wa~ repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
9g.2 g of the dimerized fatty acid~
65q2 g o~ the first epoxy resinl 82.7 g of the second epoxy resin, 14.9 g of the first unsaturated fatty acid, 38.0 g of the second unsaturated fatty acid, 65.0 g of l-methoxy propanol-2 and 0.3 g of Cr(III) 2-ethylhexanoate.

The dropping funnel was filled with a homogeneous mixture of:
24.2 g o~ ~tyrene, 5.8 g of methylmethacrylate, 20.9 g of acrylic acid, 47.3 g of the glycidyl~ester, 1.8 g of dicumyl peroxide, and 35.1 g of 1-methoxy propanol-2.

After the cooling of the contents of the reaction flask to 100C, 9.1 g o~ N,N-dimethylethanolamine were added after which, over a period of two hours, 380 g of demineralized water were also added.

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Example 3 was repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
105.4 g of the dimerized fatty acid, 69.4 g of the first epoxy resin, 87.9 g of the second epoxy resin, 5.3 g of the first unsaturated fatty acid, 52.0 g of the second unsaturated fatty acid, 70.0 g of l-methoxy propanol-2 and 0.3 g of Cr(III~ 2-ethylhexanoate.

The dropping funnel was filled with a homogeneous mixture of:
.4 g of styrene, :~: 15 4.6 g of methyl methacrylate, 16.8 g of acrylic acid, 37,8 g of the glycidyl ester, 1.4 g of dicumyl peroxide and .:; 30~1 g of l-methoxy propanol-2.
, : ~ 20A~ter the cooling of the contents of the reaction flask to 100C, 7.3 g of N,N-dimekhylekhanolamine were added a~ter which, over a period of two hours, 262 g o~ demineralized water were also added.
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~C0 2238 Example 5 was repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
101.3 g of the dimerized fatty acid, 63.1 g of the first epoxy resin, 97.8 g of the second epoxy resin, 5.3 g of the unsaturated fatty acid, 52.5 g of the second unsaturated fatty acid, 70.0 g of l-methoxy propanol-2 and 0.3 g o~ Cr(III) 2-ethylhexanoate.

After the cooling of the contents of the reaction flask to 100C, 7.3 g of N,N-dimethylethanolamine were added after which, over a period of two hours, 262 g of demineralized 15water were also added.

EX~MPLE 7 Example 5 was repeated ln it~ entirety except for the :~ following.
In the reaction ~lask were homogeneously mixed:
97.0 g of the dimerized fatty acid, 56.7 g of the first epoxy resin, 107.8 g of the second epoxy resin, ~: 5.4 g of the first unsaturated fatty acid, 53.1 g of the second unsaturated fatty acid, -~ ~5 70.0 g of l methoxy propanol-2 and 0.3 g of Cr(III) 2 ethylhexanoate.
, :
~: After the cooling of the contents of the reaction flask to 100C, 7.3 g of N,N-dimethylethanolamine were added after ~: which, over a period of two hours, 248 g of demineralized ^~ 30 water were also added.
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Example 3 was repeated in its entirety except for the following.
In the reaction flask were homoyeneously mixed:
92.9 g of the dimerized fatty acid, 61.1 g of the first epoxy resin, 77.4 g of the ~econd epoxy resin, 23.2 g of the first unsaturated fatty acid, 25.4 g of the second unsaturated fatty acid, 60.0 g of dipropylene glycol monomethyl ether, 21.3 g of isopropanol and 0.4 g of Cr(III) 2-ethylhexanoate.
.:-The dropping funnel was filled with a homoyenous mixture f:
28.7 g of styrene, 6.9 g of methyl methacrylate, 24.8 g of acrylic acid, 56.1 g of the glycidyl ester, 3.5 g of dicumyl peroxide and 8.0 g of isopropanol.

The contents of the reaction flask were heated to re~lux temperature (about 130C) and maintained at reflux for 3 hours, after which the contents of the dropping funnel were added over a period of 1 hour while keeping the reaction mixture at reflux temparature. The reaction mixture temperature was subsequently maintained at reflux for another 3 hours.
After the cooling of the contents of the reaction flask to 100C, 10.8 g of N,N-dimethylethanolamine were added after which, over a period of two hours, 553 g of demineralized water were also added.

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ACo 2238 Example 8 was repeat~d in its entirety except for the following.
The dropping funn~l was filled with a homogenous mixture 5 of:
52.9 g of styrene, 17.2 g of 2-hydroxyethyl methacrylate, 36.1 g of butyl methacrylate, 8.7 g of acrylic acid, 5.1 g of dicumyl peroxide and 8.0 g of isopropanol.

I After the cooling of the contents of the reaction flask to 100C, 10.9 g of N,N-dimethylethanolamine were added aftar which, over a period of two hours, 553 g of demineralized water were also added.

.
Example 9 was repeated in its entlrety except for the following.
In the reaction flask were homogeneously mixed:
121.0 g of the dimerized ~atty acid, 110.2 g of ~he ~ir~t epoxy resin, 23.3 g of the first unsaturaked fatty acid, 25.5 g of ~he second unsaturated fatty acid, Ç4.0 g o* dipropylene glycol monomethyl ether, 17 2 g of isopropanol and 0.4 g of Cr(III) 2-ethylhexanoate.

After the cooling of the contents of the reaction flask to 100C, 8.7 g of N,N-dimethylethanolamine were added after which, over a period of two hours; 500.5 g of demineralized water ware also added.

. .

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, In a 2 liter reaction flask fitted with a stirrer, a thermometer, a reflux condenser and a dropping funnel were homogeneously mixed:
140.7 g of the dimerized fatty acid, 90.2 g of a third epoxy resin (a 3,4-epoxycyclo hexylmethyl-3,4-epoxycyclohexyl carboxylate commercially available under the trade designation Araldite CY-179 from Ciba-Geigy~, 23.4 g of the first unsaturated fatty acid, 25.7 g of the second unsaturated fatty acid, 49.3 g of methyl isobutyl keton~, 20.0 g of dipropylene glycol monomethyl ether and 0.4 g of Cr(III) 2-ethylhexanoate.
~ 15 The dropping funnel was filled with a homogeneous mixture `': o~:
~ 54.6 g of styrene, ;~ 13.6 g of 2-hydroxyethyl methacrylate, 37.3 g of butyl methacrylate, ~ 20 11.3 g of acrylic acid, -~ 3.2 g of dicumyl peroxide and ; 20.0 g o~ dipropylene glycol monomethyl ether.

Aftsr ventilating, the reaa~ion fla~k and dropping funnel were brought under a nitrogen atmosphere. The contents of the reaction flask were then heated to 120C and mainkained at that temperature for 3 hours, after which the temperature of -the reaction ~lask was brought to 130C, the contents of the dropping funnel added and the reaction mixture temperature maintained at 130C fox another 3 hours.
;~ 30After the cooling o~ the contents of the reaction fla~k to 100C, 14.0 g of N,N-dimethylethanolamine were addad a~ter -~which, ovex a period of two hours, 677 g of demineralized water were also added.

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` :- - ' ' i , ' ' , -In a 2 liter reaction flask fitted with a stirrer, a thermometer, a reflux condenser and two dropping funnels were homogeneously mixed:
235.5 g of a second dimerizad fatty acid (commercially available under the trade designation Pripol 1009 from Unilever), 149.6 g of the third epoxy resin, 38.9 g of the first unsaturated fatty acid, 42.6 g of the second unsaturated fatty acid, 82.5 g of methyl isobutyl ketone and 0.7 g of Cx(III) 2-ethylhexanoate.
The first dropping funnel was filled with 70.0 g of diethylene glycol monobutyl ether.
The second droppi~g funnel was filled with a homogenous mixture of:
86.8 g of styrene, 31.2 g o~ 2-hydroxypropyl methacrylate, 59.3 g of butyl methacryl~te, 14.4 g of acrylic acid and 8.3 g o~ dicumyl peroxide.
After ventilating, the reaction flask and dropping funnels were brought under a nitrogen atmosphere. rrhe contents o~ the reaction flask were then heated to 120~C and maintained at that temperature for 3 hours, after which the contents of the first dropping funnel were added and khe temperature of the reaction flask brought to 130C~ ~he contents of the ~econd dropping funnel were then added at a ~ constant rate over a period of 2 hours, after which the -~ 30 temperature was maintained at 130~C for another 3 hours.
After the cooling of the contents of the reaction flask to 100C, 14.3 g of N,N-dimethylethanolamine were added after which, over a period of two hours, 755 g of damineralized water wer also added.
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Example 12 was repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
237.4 g of the dimerized fatty acid, 150.8 g of the third epoxy resin, 78.4 g of tha first unsaturated fatty acid, 82.6 g of l-methoxy propanol-2 and 0.7 g of Cr(III) 2-ethylhexanoate.

After ventilating, the reaction flask and dropping funnels were brought under a nitrogen atmosphere. The contents of the reaction flask were then heated to 120C and - maintained at that temperature for 3 hours, after which the~ contents of the first dropping funnel were added and the ; 15 temperature of the reaction flask brought to 130C. The contents of the second dropping funnel were then added at a constant rate over a period of 1 hour, after which the ; *empsrature was maintained at 130C for another 3 hours.
After the cooling of the content~ of the reaction flask to 100C, 14.3 g of N,N-dimethylethanolamine ware adda~ after which, over a period of two hours, 922 g of demineralized water were also added.
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Example 13 was repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
254.3 g of the dimerized fatty acid, 161.6 g of the third epoxy resin, 84.0 g of the first unsaturated fatty acid, 84~9 g of l-methoxy propanol-2 and 0.7 g of Cr(III) 2-ethylhexanoate.

The second dropping funnel was filled with 166.7 g of the homogenous mixture of monomers.
After the cooling of the contents of the reaction flask to 100C, ll.9 g of N,N-dimethylethanolamine were ~dded after which, over a period of two hours, 834.2 g of demineralized lS water were also added.

Example 13 was repeated in its entirety except that, after the cooling o~ the aontents of the reaction ~lask to lOO~C, 10.8 g of N,N-dimethylethanolamine were added a~ter which, over a period of two hours, 733.3 g of demineralizecl ; water were also added.

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Properties ~ ersions , .
Dispersion o~ Solids Content Viscosity Mean Particle Example (wt%) (Pa.s.~ pHsize (nm) _ 1 41.5 0.44 8.9 217 2 44 0.53 8.8 284 3 37 0.58 8.4 174 4 44 0.92 8.2 161 51 0.57 7.9 281 ::~ 10 6 51 0.39 7.7 331 7 52 0.50 7.8 251 8 37 0.36 8.2 g2 9 38 0.26 9.0 119 0.59 8.9 159 11 35 0.56 8.9 74 .~ 12 42 4.8 8.8 148 13 38 4.5 8.8 94 ::: 14 ~0 1.4 8.8 150 :; 15 42.5 4.2 8.6 214 :~ The following Examples 16 to 19 are comparative examples ~`; demonstrating the effect of utilizing no unsaturated fatty :;. ` acid (no unsaturated functi.onality).

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Example 2 was repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
56.2 g of the dimerized fatty acid, 39.8 g of sebacic acid, 147.8 g of the first epoxy resin, 56.2 g of stearic acid, 65.0 g of l-methoxy propanol-2 and 0.3 g of Cr~III) 2-ethylhexanoate.

After the cooling of the contents of the reaction ~lask to 100C, 9.7 g of N,N-dimethylethanolamine were added after which, over a period of two hour~, 399.7 g o~ demineralized water were also added.
The resulting aqueous dispersion was unstable as phase separation occurred.

Example 8 was repeated in its entirety exaept ~or the following.
In the reaction ~lask were homogeneously mixed:
102.7 g of the dimerized fatty acid, 67.6 y of the first epoxy resin, -I 85.6 g of the second epoxy resin, 24.1 g of dimethylolpropionic acid, 60.0 g of dipropylene glycol monomethyl ether, 21.3 g o~ isopropanol and 0.4 g of Cr(III) 2-ethylhexanoate.

The resulting aqueous dispersion was unstable as phase separation occurred.

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I Example 8 was repeated in its entirety except for the ~ollowing.
In the reaction flask were homogeneously mixed:
106.9 g of the dimerized fatty acid, 70.3 g of the first epoxy resin, 89.0 g of the second epoxy resin, 13.8 g of propionic acid~
; 60.0 g of dipropylene glycol monomethyl ether, 21.3 g of isopropanol and 0.4 g of Cr(III) 2~ethylhexanoate.

The resulting aqueous dispersion was unstable as phase separation occurred.
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Example 13 was repeated in its entixety except for the following.
In the reastion flask were homogeneously mixed:
237.5 g of the dimerized fatty acid, ;~ 150.9 g of the third apoxy resin, 78.2 g of stearic acid, 82.6 g of l-methoxy propanol~2 and 0.7 g of Cr(III) 2-ethylhexanoate.

After the cooling of the contents of the reaation flask to 100C, 14.3 g of N,N-dimethylethanolamine were added after which, over a period of two hours, 1019.3 g of demineralized water were also added.
The resulting aqueous dispersion was unstable as phase separation occurred.

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ACo 2238 ~ he following Examples 20 to 22 are comparative examples demonstrating the effect of utilizing an unsaturated fatty acid but with substantially no conjugated double bonds.

COMPAR~TIVE EX~MPLE 20 Example 2 was repeatad in its entirety except for the following.
In the reaction flask were homogeneously mixed:
56.3 g of the dimerized fatty acid, 39.9 g of sebacic ac~d, 148.1 g of the first epoxy resin, 55.7 g of oleic acid, 65.0 g of l-methoxy propanol-2 and 0.3 g of Cr(III3 2-ethylhexanoate.

After the cooling of the contents of the reaction flask to 100C, 9.7 ~ of N,N-dimethylethanolamine were added a~ter which, over a period of two hours, 399.7 g of dsmineralized water were also added.
The resulting aqueous dispersion was unstable as phase separation occurred.

COMP~ARATIVE XAMPLE 21 Example 20 was repeated in its entirety except ~or the following.
In the reaction flask were homogeneously mixed:
55.3 g of the dimerized fatty acid, 39.9 g of sebacic acid, 145.5 g of the first epoxy resin, 60.0 g o~ the second unsaturated fatty acid, 65.0 g of l~methoxy propanol-2 and " 0.3 g of Cr(III) 2-ethylhexanoate.

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The resulting aqueous dispersion was unstable as phase separation occurred.

Example 13 was repeated in its entirety except for the following.
In the reaction flask were homogeneously mixed:
233.7 g of the dimerized fatty acid, 148.5 g of the third epoxy resin, 84.5 g of the second unsaturated fatty acid, 82.6 g of l-methoxy propanol-2 and 0.7 g of Cr~III) 2-ethylhexanoate.
;:
The resulting aqueous dispersion was unstable as phase separation occurred.

Preparation Qf Coating compositions In the following Examples 23 to 41, a number o~
unpigmented and pigmented coating compositions ln accordanae with the present invention were prepared by homogeneously mixing the dispersion, melamine hardener, optionally - demineralized water, optionally 2 butoxy ethanol, optionally diethylene glycol monobutyl ether (DEGMBE) and optionally ~ titanium dioxide (pigment) as set forth in Table II.
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The melamine hardener used in these Examples was a 90 percent solids melamine resin commercially available under the trade designation Cymel 327 ~rom American Cyanamid.

The demineralized water was added to adjust the coating compositions to a spray viscosity of about 0.1 Pa sec. (run-out viscosity o~ 30 sec. in a Ford Cup No. 4)O

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The solids contents of these coating compositions were measured in the same manner as described above for the dispersions, and the results are also presented in Table II.

Each o~ these coating compositions was applied onto a zinc phosphate pretreated steel panel (Bonder 132) and cured in a baking oven for 30 minutes at a temperature of 140C
(Examplee 23 to 36) or 150C (examples 37 to 41). Various properties of the so-obtained coatings were measured, and the results are presented below in Table III.

10The Persoz hardness was determined in accordance with French Industrial Standard NF T30-016, and the results are expressed in seconds. An acceptable minimum for automotive paint is about 180 seconds.

The flexibility ratings of the coatings were determined 15with a ball impact tester in accordance with ASTM D2794~69 using a ball weight of 0.908 kg, a ball diameter of 15.9 mm and an aperture of 16.3 mm, the results being expressed in kg.cm. An acceptable minimum flexibility for a primer/surfacer for khe coat side is about 35 kg,cm, with the ~0 maximum measurable value being 85 kg.cm. An acceptable minimum flexibility for a pi~mented or clear topcoat ~or the coat side is about 20 kg.cm.

~` The coatings were also tested via the Erichsen - indentation test with the results being expressed in mm. A
test value of higher than 6 is indicative of a flexible coating, and a value of 2 a brittle coating.

The gloss of the coating was dstermined in aacoxdance with U.S. Industrial Standard ASTM D-523 at 60F and 20F. A
gloss value on a steel substrate of ahove 80 at 60F is considered high.
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Coatinq Com~osition Formulations 2-Butoxy Titan. Solids Disp. Hardener Water ethanol DEGMBE Diox. Content 5 Exp. Di~p. (~rams) [~rams) (~rams~ ~rams) (~rams) (qrams) (wt~) ' 23 Ex. 1 100.0 15.32.0 2.0 ~ 43.3 24 Ex. 2 100.0 16.23.4 2.0 ~ 44.9 25 Ex. 3 100.0 13.73.0 1.7 ~ 38.9 26 Ex. 4 100.0 16.25.0 ~ --- 45.3 27 Ex. 5 100.0 18.96.6 2.3 --- --- 49.7 28 Ex. 6 100.0 18.98.1 2.3 ~ -- 49.3 29 Ex. 7 100.0 19.310.5 2.4 --- --- 49.1 30 Ex. 8 100.0 13.72.5 1.7 --- --- 40.5 31 Ex. 9 100.0 14.0 --- 1.8 --- --- 41.0 32 Ex~10 100.0 14.83.2 1.8 ~ - 42.1 33 Ex. 2 100.0 16.227.6 2.0 --- 57.5 54.9 34 Ex. 4 100.0 16.224.0 2.1 --- 57.5 56.0 35 Ex. 8 100.0 13.721.9 1.7 --- 50.5 53.6 36 Ex.ll 100.0 12.73.0 1.6 --~ 36.4 `~20 37 Ex.12 100.0 19.912.5 --- 4.6 --- 40.5 38 Ex.13 100.0 18.07.9 --- 4.1 --- 39.4 39 Ex.14 100.0 l9oO2.3 --- 4.1 --- 43.1 40 Ex.15 100,0 20.37.3 --- 4.3 --- 43.8 41 Ex.13 100.0 1~.05.6 --- 4.143.4 52.7 :`:

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~CO 2238 TABLE I I I
Properties of the Coatings Flexibility Coating Persoz (k~. cm) Erichsen 5 Coating of Thick. Hard. Coated Back Indent. Gloss Exam~le (~m~ (sec) Side _ Side (mm) 60 F 20 F
23 40 273>85 >85 9.1 89 63 24 41 272>85 >85 8.6 93 72 38 263>85 >85 8.7 94 73 26 37 260~85 >~35 8.5 93 70 27 38 246>85 >85 8.8 88 75 28 41 285>85 >85 8.8 90 76 29 39 2g9~85 >85 8.5 92 78 36 269>85 >85 8. ~99 81 31 37 302>85 >85 8.3100 85 32 40 ~48>85 >85 8.2 96 82 33 40 265>85 70 8.4 85 66 34 39 250>85 80 8.0 86 68 39 245>85 >85 8.1 90 75 36 43 286>85 4~ 7O7 96 73 37 39 292 30 2 5.4 91 73 38 41 297 35 8 6.3 96 72 39 44 285 34 8 6.7 96 75 : 40 44 298 31 7 5. ~96 73 41 40 287 32 ~ 6.0 95 70 .
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Testing of Clearcoats The coatings o~ Examples 36~40 are especially suited ~or use as clear-coats, and were further tested for acid resistance and durability as set forth below. A comparison was also done against a standard acrylic clearcoat ("re~erence"), which was a conventional thermosetting acrylic commercially applied in automotive production lines.

Zinc phosphate steel panels were first coated with a conventional epoxy primer to a dry film thickness o~ 30~m, cured ~or ? minutes at 170C, then subsequently coated with a conventional polyester/melamine sur~acer to a dry film thickness of 40~m, and cured for an additional 20 minutes at 140C.

In an atmosphere having a relative humidity of 65 percent, the precoated panels were oversprayed with a waterborne basecoat (as described in EP-A-0287144) to a dry film thickness of 15-20~m. The resulting test panels were predried in a baking oven for 15 minutes at a te~perature o~
60C, then overcoated with the clear coat to a dry film thickness of 40-45~m and cured for an additional 30 minutes at 150C.

Acid resistance was tested in accordance with a spot test utilizing a solution of 52 percent sulfuric acid. The results are presented in Table IV, and are expressed on a scale of 0 to 5, with 5 indicating no change and 0 indicating failure.

Durability was tested with the aid of a Weather-O-Meter using a carbon arc and a 17/3 cycle for 2000 hours. Gloss was then determined in accordance with ASTM D-523 at 60F (as above), and the results are also presented in Table IV.

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Durability o~ Clear Coatin~

Coating of AcidGloss before Gloss After Example ResistanceExposure _ Exposure 5Reference 0-l 88 85 ~ 38 4-5 91 89 : 39 4-5 91 89 Only a limited number of preferred embodiments of the present invention have been described above. One skilled in ; the art, however, will recognize numerous substitutions, modifications and alterations which can be made without departing from the spirit and scope of the invention as limited by the following claims.

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Claims

1. A hybrid polymer which comprises (A) a polymer onto which (B) at least one addition polymer-based chain has been grafted, wherein:
i. the polymer (A) is an unsaturated fatty acid group functionalized poly(epoxyester), which is the reaction product of (1) an epoxy-terminated poly(epoxyester) and (2) an unsaturated fatty acid component, at least a portion of which comprises an unsaturated fatty acid with conjugated double bonds, ii. the addition polymer-based chain (R) has an acid number of from about 20 to about 100; and iii. the at least one addition polymer based chain (B) is grafted onto polymer (A) via the addition polymerization of free-radically polymerizable monomers in the presence of the unsaturated fatty acid group functionalized poly(epoxyester).

2. The hybrid polymer according to claim 1, comprising from about 40 weight percent to about 90 weight percent of the polymer (A) and from about 10 weight percent to about 60 weight percent of the addition polymer-based chains (B), based upon the total weight of the hybrid polymer.

3. The hybrid polymer according to claim 1, wherein the epoxy-texminated poly(epoxyester) is the reaction product of:

n moles of a bisepoxide having a number average molecular weight (Mn) in the range of from about 150 to about 2000, and n-1 moles of a dicarboxylic acid having from about 4 to about 40 carbon atoms, wherein n = 2-10.

4. The hybrid polymer according to claim 3, wherein the poly(epoxyester) has an Mn in the range of from about 400 to about 20,000.

5. The hybrid polymer according to claim 3, wherein the poly(epoxyester) has an Mn in the range of from about 2000 to about 20,000.

6. The hybrid polymer according to claim 3, wherein the bisepoxide is selected from a diglycidyl ether of bisphenol A, and epoxy oligomers from epichlorohydrin and bisphenol A.

7. The hybrid polymer according to claim 3, wherein the bisepoxide is selected from cycloaliphatic bisepoxides, and epoxy oligomers from epichlorohydrin and hydrogenated bisphenol A.

8. The hybrid polymer according to claim 3, wherein the dicarboxylic acid comprises a dimerized fatty acid.

9. The hybrid polymer according to claim 1, wherein the unsaturated fatty acid comprises at least 10 mole percent of a fatty acid with conjugated double bonds.

10. The hybrid polymer according to claim 9, wherein the unsaturated fatty acid comprises at least 30 mole percent of a fatty acid with conjugated double bonds.

11. The hybrid polymer according to claim 1, wherein the unsaturated fatty acid has from about 12 to about 26 carbon atoms.

12. The hybrid polymer according to claim 1, wherein a portion of the unsaturated fatty acid is replaced with a monofunctional compound of the general formula (I) R - X (I) wherein R is a hydrocarbon group having from 1 to 40 carbon atoms, and X is a functional group which is reactive with an epoxy group.

13. The hybrid polymer according to claim 12, wherein R
is an alkyl, aralkyl, aryl or cycloalkyl group having from 1 to about 24 carbon atoms, and X is an amino or carboxyl group.

14. The hybrid polymer according to claim 13, wherein the monofunctional compound comprises a monocarboxylic acid.

15. The hybrid polymer according to claim 1, wherein the unsaturated fatty acid is utilized in an equivalence ratio of carboxyl groups/epoxy groups of at least about 1:4.

16. The hybrid polymer according to claim 1, wherein the unsaturated fatty acid is utilized in an equivalence ratio of carboxyl groups/epoxy groups of at least about 1:2.

17. The hybrid polymer according to claim 15, wherein the combination of the unsaturated fatty acid and monofunctional compound is utilized in an equivalence ratio of carboxyl + X groups/epoxy groups of from about 1:4 to about 1:1. :

18. The hybrid polymer according to claim 1, wherein acid groups of the hybrid polymer are at least partially neutralized to render the hybrid polymer water-dispersible.

19. An aqueous dispersion comprising the water-dispersible hybrid polymer according to claim 18.

20. An aqueous coating composition comprising the aqueous dispersion according to claim 19.

21 . The aqueous coating composition according to claim 20, further comprising a curing agent for hydroxyl groups of the hybrid polymer.

22. A primer/surfacer comprising the aqueous coating composition according to claim 20, wherein the bisepoxide of the unsaturated fatty acid group functionalized poly(epoxyester) is selected from a diglycidyl ether of bisphenol A, and epoxy oligomers from epichlorohydrin and bisphenol A.

23. The primer/surfacer according to claim 22, further comprising a curing agent for hydroxyl groups of the hybrid polymer.

24. A clearcoat comprising the aqueous coating composition according to claim 20, wherein the bisepoxide of the unsaturated fatty acid group functionalized poly(epoxyester) is selected from cycloaliphatic bisepoxides and epoxy oligomers from epichlorohydrin and hydrogenated bisphenol A.

25. The clearcoat according to claim 24, further comprising a curing agent for hydroxyl groups of the hybrid polymer.

26. A pigmented top coating comprising the aqueous coating composition according to claim 20, wherein the bisepoxide of the unsaturated fatty acid group functionalized poly(epoxyester) is selected from cycloaliphatic bisepoxides, and epoxy oligomers from epichlorohydrin and hydrogenated bisphenol A.

27. The pigmented top coat according to claim 26, further comprising a curing agent for hydroxyl groups of the hybrid polymer.