US3218274A - Two-package coating system comprising a polyester having an acid number of at least 50 in one of the packages thereof - Google Patents

Description

essary characteristics.

esters, and particularly epoxidized fatty oils.

United States Patent 3 218 274 TWO-PACKAGE coArrNd SYSTEM COMPRISING A POLYESTER HAVING AN ACID NUMBER OF AT LEAST 50 IN ONE OF THE PACKAGES THEREOF Robert vA. Boller, Rich'field, and Richard B. Graver,

Minneapolis, Minn., assignors to Archer-Daniels-Midland Company, Minneapolis, Minn., a corporation of Delaware No Drawing. Filed Feb. 13, 1961, Ser. No. 88,613

18 Claims. (Cl. 26022) This invention relates to new coatings vehicle compositions which form hard, and improved coatings. These new coatings vehicles are comprised of the reaction products of non-drying epoxidized fatty ester materials, such .as epoxidized fatty oils or epoxidized fatty glycerides,

epoxidized synthetic esters of long chain fatty acids and epoxidized fatty alcohols, with partial esters of polyols and polycarboxylic acid or anhydride materials. More particularly, this is an improvement in the method of formulating economical coatings vehicles using solvent mixtures of epoxidized long chain fatty ester systems having internal oxirane groups and partial esters of modified or unmodified phthalic acid or anhydride materials with polyhydroxy compounds, and the products derived therefrom.

Heretofore, epoxidized long chain monomeric and polymeric fatty esters, such as fatty oils and the like, have served more beneficially in a non-hardening relationship, as plasticizing agents in resinous compositions. Otherwise the formation of hard films or plastics with epoxidized oils has been through use of strong polycarboxylic acids, including certain adducts of such acids or anhydrides which have a low pH value on other defined nec- However, with these materials it has been found that there are a number of problems present in attempting to utilize such acids and anhydride materials at high solids levels with conventional solvents. This is particularly true with the low cost phthalic acid and phthalic anhydride when used with the epoxidized fatty ester compounds, as epoxidized fatty oils or fatty glycerides, and the epoxidized esters of fatty acids. Some of these problems are:

(1) Low solubility is obtained in conventional paint and varnish solvents.

(2) Low solids are required.

(3)'Viscosity control is difficult.

(4) Raw material cost is uneconomical.

(5) Versatility in formulating varnishes and paints is limited.

(6) Seeding in the films is difficult to prevent.

By comparison it has now been particularly discovered that the lower cost phthalic acid and phthalic anhydride can be more practically, economically and effectively utilized to form coatings vehicles in combination with economical paint and varnish solvents and epoxidized fatty This is accomplished by first forming esterification products of the particular polycarboxylic acid materials and polyhydroxyl alcohols with a retained acid value of 50 or more as described herein. Conventional paint and varnish solvent coating systems of epoxidized esters of fatty acids can now be used with phthalic acid materials more effectively and in a more economically'feasible manner to form pigmented and unpigmented hard, mar resistant, durable films. Further, the phthalic acid material may be modified with additional polyester for forming improved hard Accordingly, it is an object of this invention to provide improved, hard, mar-resistant, durable coatings from solvent solutions of normally non-drying epoxidized fatty ester materials and partial esters of phthalic acid mate- 3,218,274 Patented Nov. 16, 1965 rials having controlled viscosity in conventional paint and varnish solvents.

Another object is to form and provide clear and pigmented dry films from epoxidized fatty oils and modified anhydrides which have outstanding hardness, durability, color retention and mar resistance.

An additional object of this invention is to provide improved hard coating films of epoxidized fatty ester and partial ester materials; including the processof preparing pigmented and non-pigmented coating vehicle compositions for making such films comprising mixing non-drying epoxidized oils, epoxidized glycerides, epoxidized esters of long chain fatty acids, and/or epoxidized fatty alcohols, and mixtures thereof in combination with partial esters of phthalic acid or phthalic anhydride materials and polyfunctional alcohols having aretained acid value of at least 50 in a paint, varnish or enamel solvent, as indicated.

Another object of this invention is to provide economically proficient air drying and baking paint vehicles of epoxidized fatty esters, as polyepoxidized fatty oils and polyepoxidized esters of long chain fatty acids, in combination with partial esters of esterificationpolymers .of phthalic acid material and polyhydroxy alcohol. This combination forms clear and pigmented, hard, tough, mar resistant coatings with excellent adhesion, flexibility, chemical resistance, durability and color retention To the accomplishment of the foregoing and related ends, this invention then comprises the features above and hereinafter set forth, as more fully described and particularly pointed out by certain illustrative embodiments. These are indicative of the ways in which improved coatings vehicles can be made from non-drying epoxidized esters of long chain fatty compounds in combination with partial ester condensation polymers of polycarboxylic acids, and particularly polycarboxylic acid anhydrides and polyols, and the manner in which hard, dur'able,'water and chemical resistant, flexible films are obtained.

The epoxidized esters of fatty acid compounds employed in this invention are those of monomeric form having preferably 12 to 22 carbon atoms with internal oxirane groups in the fatty chain portions and 1 through 10 carbon atoms in the mono and polyhydric alcohol portions with or without internal oxirane groups in the alcohol chain portions. The methods of epoxidation of such compounds are well known to the art. Illustrative thereof are some preferred types of monomeric epoxy fatty ester compounds as epoxidized linseed oil, epoxidized soybean oil, epoxidized safiiower oil and the like having an iodine value of over before epoxidation and an oxirane value of at least 6% after epoxidation. Also, inclusive of the fatty esters, there may be utilized the many other long chain epoxidized fatty oils, fatty alcohols and mono or polyhydroxy ester derivatives of ,vegetable oil, animal oil, marine oil and similar epoxidized synethetic compounds having modified or unmodified fatty or aliphatic and cycloaliphatic chains of 12 to 26 carbon atoms in the base chains. Such base chains also preferably have from 1 through 10 carbon atoms in substituent chain portions and the preferred hard film forming compounds contain at least about 6% to 10% and more internal oxirane value. In addition, the mono and polyalcohol ester derivative of the fatty chains may or may not contain one or more oxirane groups, in the ester portion. The preferred fatty ester oxirane compounds are those described and prepared in the manner shown in Wahlroos Patent No. 2,813,878, Niederhauser Patent No. 2,485,160 and 2,543,419, Phillips et al. No. 2,779,771, Dazzi 2,745,846, Swern et al. 2,457,329 and the like.

Additional expoxidized fatty .ester compounds having a minimum of about 3% oxirane value may be indicated as epoxy 2-ethyl hexyl tallate, epoxy 1-5 pentane diol dioleate, epoxy hexanetriol dioleate mono acetate, and the like. Other compounds with 1 to or more carbon atoms in the alcohol portion are epoxidized mono and polyhydroxy alcohol esters of fatty acid chains, including the epoxidized fatty alcohols, as 9,10-epoxy-octadecanol, methyl oleate, oleyl alcohol, 9,IO-dihydroxyoctadecanol and the like. These may have non-interfering substituents as halogen or other groups, as may be illustrated by epoxidized chlorohydroxyoctadecanol and the like containing an internal oxirane group or groups. Obviously, it will be recognized that there are many epoxidized fatty oil and related like aliphatic and cycloaliphatic epoxidized compounds and epoxidized derivatives which are available. Essentially the typical fatty oils and fatty esters are indicated. However, many more can be illustrated and named, for example, epoxidized trilinoleate, trioleate, mono-oleate, monolinoleate, monolinolenate, monostearate dilinoleate, dilinoleate mono-oleate and many other well known glycerol esters. Also included are the substituted and unsubstituted epoxidized monoand polyhydric alcohol re-esterified and derivative products, including ethylene glycol, diethylene glycol, mono, di, and polypentaerythritol, sorbitol, and the like. Essentially, it will be recognized that epoxidized products derived from dimerized and trimerized fatty acids and fatty esters, including the epoxidized fatty nitriles, amides and amine derivatives of the fatty chain compounds as herein described. Such compounds also include, for example, fatty esters, as mono-, di-, and polypentaerythritol esters of soy, tall, linseed, and the like, derived from fatty oils, fatty acids and similar aliphatic and cycloaliphatic compounds of analogous structure. Other such derivatives may include epoxidized oleyl phosphate, dioleyl phosphate, oleyl chloride, octadeca dienyl chloride, oleyl mercaptan, and mixtures thereof and the like to form similar or addition reaction products, to these herein described.

It will be understood that the present film coating compositions, as herein described, are prepared and normally utilized as two package systems in the field of vehicle coating systems. It has not been found possible .to neutralize the partial esters in the presence of the epoxidized compounds and obtain systems which cure at ordinary room. temperature. Many neutralizing agents such as amines and the like form salts with the described partial esters which are usually insoluble in the epoxidized esters of fatty acid material and the conventional aromatic paint and varnish solvents. The preferred solvents are of the aromatic type as xylol or toluol, used alone or in combinatioin with esters of ketones and/ or other con- .ventional enamel, paint and varnish solvents having boiling points between about 100186 C. and dry points about 110209 C. Such solvents are well known to the coating art. As indicated, the use of the epoxidized fatty esters described with the partial esters of resinous polycarboxylic acid material, hereinafter described, require a two package system for subsequent combination, by blending just before application and use. The use of two component systems has found increasing application since unusual film properties can be obtained which are superior to those obtainable from one package systems.

In general, the partial esters are esterification polymers which can be represented by the reaction and resultant empirical formulas, as follows:

where n is an integer of at least 2 and preferably greater than 2, usually 3 or 4 but may be greater. R and R are general symbols for the alkyl, aromatic, carbon or other organicstructures usually present in polyhydroxy alcohols and polycarboxylic acids, respectively.

In this case R represents the balance of the polyhydroxy compound and R represents the balance of the polycarboxylic anhydrides. Use of a polycarboxylic acid in place of the polycarboxylic anhydride may be represented thus:

Of course the final product in this latter case may not be as simple as represented above. It is recognized that the second reaction may yield polymers and free acid. But the type of molecule represented above will be the predominate species.

As indicated, the preferred partial ester of polycarboxylic acid material is a polyhydroxymodified phthalic acid material. This may include, in part, the more expensive hexachl-oroendomethylene tetrahydrophthalic acid or anhydride materials in admixture with the phthalic acid or phthalic acid anhydride, all of which are reacted with a polyhydroxy alcohol forming a mixture of partial esters, as herein described and illustrated. Other examples of less preferred polycarboxylic acid material portions for forming modifying partial esters are maleic acid or anhydride, tri-mellitic acid or anhydride, tetrachlorophthalic acid or anhydride, monochlorophthalic acid or anhydride, tetrahydrophthalic acid or anhydride, hexahydrophthalic acid or anhydride, and mixtures of the same, and the like, for modifying reactivity. For some purposes, if it is desirable, suitable of these materials may be utilized alone, or in mixed form, for preparation of partial esters, which may then be mixed with the preferred partial esters.

The polyfunctional alcohols, for example, can be ethylene glycol, propylene glycol, glycerol, trimethylolethane, trimethylopropane, sorbitol and preferably pentaerythritol, dipentaerythritol, tripentaerythritol, or mixtures of the same, and the like. These are exemplary of the saturated alcohols used herein.

The following examples are exemplary and illustrate some preferred film forming partial esters and some less preferred partial esters or condensation esterification polymers for forming coating materials. In the overall, these are different chemicals prepared from relative initial ratios of a minimum of about 1.0 carboxyl to 1 hydroxyl to 3.0 carboxyl to 1 hydroxyl and preferably about 1.8 carboxyl to 1 hydroxyl, and reacted to use preferably all the hydroxyl groups with retention of an acid value of at least 50 in the said vehicle package portion, and forming the improved coating material herein provided.

EXAMPLE I This represents a partial ester of phthalic anhydride and pentaerythritol.

To a reaction flask equipped with a stirrer, thermometer and condenser was charged 375 parts phthalic anhydride, parts of pentaerythritol and 30 parts xylol by weight. The mixture was heated to 300320 F. and held for about 30 minutes. After cooling to 250 F., 160 parts n-butanol and parts xylol were added. The partial ester obtained had a viscosity of 7.3 stokes, an acid value of about 287, a color of 1 on the Gardner-Holdt scale and was 60 percent solids.

EXAMPLE II This represents a mixed partial ester of phthalic anhydride, maleic anhydride and pentaerythritol.

250 parts phthalic anhydride, 83 parts maleic anhydride, 120 parts pentaerythritol and 30 parts xylol werecharged and reacted as in Example I. The product was reduced to 60% solids with 115 parts xyltol and parts butanol. The viscosity was 11.2 stokes, and, the acid value was 312.

EXAMPLE III This represents a mixed partial ester with a functionality of two.

148 parts of phthalic anhydride, 386 parts hexachloroendomethylene tetrahydrophthalic acid anhydride, 160 parts pentaerythritol and 20 parts xylol were charged to a reactor equipped with a stirrer, thermometer, condenser and water trap for removing water of esterification. The above mixture was esterified at 300-3 F. to an acid value of 160 at which time 18 parts of water had been distilled off. The reaction product was cooled and thinned with 100 parts butanol and 240 parts xylol. The final product was at 65% solids and had a viscosity of 49.3 stokes.

EXAMPLE IV This represents a mixed partial ester with a functionality of about 4.

148 parts of phthalic anhydride, 386 parts hexachloroendomethylene tetrahydrophthalic acid anhydride, 80 parts pentaerythritol and 20 parts of xylol were charged and reacted as in Example III to an acid value of about 170. The product wa thinned to 70% solids with 80 parts butanol and 180 parts xylol. The viscosity was 74.4 stokes.

EXAMPLE V This represents a partial ester of hexachloroendomethylene tetrahydrophthalic acid and pentaerythritol with a functionality of about 4.

482.5 parts of hexachloroendomethylene tetrahydrophthalic acid, 50 parts of pent-aerythritol and 200 parts of xylol were reacted as in Example III to an acid value of 100 and thinned to 60% solids with 52.5 parts xylol and 67.5 parts of the acetate of the monoethyl ether of ethylene glycol (Cellosolve Acetate). The viscosity was 3.3 stokes.

EXAMPLE VI This represents a partial ester with a functionality of about 4.

222 parts of phthalic anhydride, 193 parts of hexachloroendomethylene tetrahydrophthalic acid, 80 parts pentaerythritol and 208 parts xylol were charged and reacted as in Example III to an acid value of about 160 and thinned to 60% NV with 54 parts xylol and 66 parts of the acetate of monoethyl ether of ethylene glycol. The viscosity was 37.4 stokes.

EXAMPLE VII This represents a mixed partial ester of tetrahydrophthalic anhydride, hexachloroendomethylene tetrahydrophthalic acid, and pentaerythritol. 152 parts tetrahydrophthalic anhydride, 389 parts chlorendic acid, 80 parts pentaerythritol and 216 parts xylol were reacted as in Example III to an acid value of about 170 and thinned to 65% NV with 5-1 parts xylol and 66 parts of the acetate of monoethyl ether of ethylene glycol. The viscosity was 110 stokes.

EXAMPLE IX This represents a mixed partial ester of hexahydrophthalic anhydride, hexachloroendomethylene tetrahydrophthalic acid and pentaerythritol. 154 parts hexahydrophthalic anhydride, 389 parts hexachloroendomethylene 6 tetrahydrophthalic acid, parts pentaerythritol and 217 parts xylol were reacted as in Example III to an AV of about 170 and thinned to 65% NV with 53 parts xylol and 67 parts of the acetate of monoethyl ether ofethylene glycol. The viscosity was 217 stokes.

EXAMPLE X This represents a mixed partial ester of phthalic anhydride, hexachloroendomethylene tetrahydrophthalic acid, trimethylolpropane and pentaerythritol. 148 parts phthalic anhydride, 389 parts hexachloroendomethylene tetrahydrophthalic acid, 31.5 parts pentaerythritol, 56.4 parts trimethylolpropane and 151.7 parts xylol were reacted as in Example III to an acid value of about 160 and thinned to 60% NV with 172.1 parts xylol and 81 parts of the acetate of monoethyl ether of ethylene glycol. The viscosity was 5 stokes.

The preferred epoxidized compounds are primarily epoxidized fatty oils or glycerides, including their substituted mono and polyhydroxy alcohol derivatives which are fundamentally esters of fatty acids having internal oxirane groups in the fatty chain portions. The following are illustrative of the normally non-drying fatty esters.

EXAMPLE XI Epoxidized soybean oil such as that sold under the trade name of Admex 710 with an oxirane oxygen content of about 6.3%, a color of 1, a viscosity of about 5 stokes, and an iodine value of less than 5. Other epoxidized soybean oils sold commercially and containing varying percentages of oxirane oxygen up to about 7% and iodine values as low as about 1 can be used.

EXAMPLE XII Epoxidized safiiower oil containing about 7.4% oxirane oxygen and prepared by the epoxidation of safflower oil using epoxidation techniques well known to the art.

EXAMPLE XIII Epoxidized linseed oil containing about 9.0% oxirane oxygen and prepared by the epoxidation of linseed oil using epoxidation techniques well known to the art.

EXAMPLE XIV Epoxidized 2-ethyl hexyl tallate. This material had the following characteristics: Acid Value-0.2, Gardner Colorl, Viscosity0.5 stokes, Specific Gravity-0.923, Oxirane oxygen content4.4%.

EXAMPLE XV Epoxidized 1-5 pentane diol dioleate. This material had the following characteristics: Acid Value0.2, Gardner Colorl, Viscosity-4.1 stokes, Specific Gravity 0.945, Oxirane oxygen content-4.1%.

EXAMPLE XVI Epoxidized hexanetriol dioleate mono acetate. This material had the following characteristics: Acid Value 0.2, Gardner Color-4, Viscosity-2.3 stokes, Specific Gravity-0.970, Oxirane oxygen content3.7%.

Mixtures of the herein described epoxidized compounds, with the described partial esters are in the ratio of 50-150 parts partial ester per parts epoxidized fatty ester and their application may be as clear varnish or pigmented vehicles, in the manner hereinafter described. The epoxy system reacts with the partial esters or resinous polycarboxylic acid materials, as follows:

R and R refer to the balance of the epoxidized material 7 and may or may not include non-interfering aromatic, alkyl, and ester substituents with or without oxirane groups, depending upon the epoxides and partial ester material.

This representation illustrates how each reaction between a free carboxyl group and an oxirane group produces a new hydroxyl group, a new ester linkage and reduces the number of free carboxyl groups.

The'preferred use is as pigmented coating vehicles. Any non-reactive inert pigment may be used by dispersing the pigment in either the epoxy portion or the partial ester portion-in a conventional manner. However, it is preferred to disperse the pigment in the epoxy portion, prior to its mixture with the partial ester portion, since the epoxy portion has superior pigment wetting properties.

V The following examples are representative of enamels prepared from the above components, as follows:

1 (A) White enamel 500 parts Rutile Titanium Dioxide (Du Ponts R-6l0 or equal) with 300 parts of the epoxidized oil of Example XI and 10 parts of a silica product marketed as Cabosil by Cabot Company were mixed and ground on a three roller mill in a conventional manner. To this grinding paste was added 500 parts of the partial ester of Example IV and 100 parts of the acetate of the mono ethyl ether of ethylene glycol (Cellosolve Acetate). This enamel was 78.7% solids and had a P.V.C. of 20.4%. Cured films had a 60 gloss of 92% upon baking at 250 for 20 minutes, or suitable air drying.

(B) Green enamel 5 parts of phthalocyanine green (Du Ponts Ramapo GP-SOlD or equal), 100 parts titanium dioxide (Du Ponts R-510 or equal) and 85 parts of the epoxidized oil of Example XIII were mixed and ground as above. This paste was mixed with 115 parts of the partial ester of Example IV and 24 parts of Cellosolve Acetate to give a green enamel with a percent solids of 78.5% and a P.V.C. of 17.3%. Films made from this enamel may 8 be air dried or baked under standard conditions and were very glossy, very, hard and resistant to chemicals.

(C) Yellow enamel A' yellow enamel with a P.V.C. 0f 14% was made by grinding 30 parts Cadmium Yellow (Imperial Color X-23l5), 270 parts titanium dioxide (Du Ponts R-6l0), 4 parts Cabosil (Cabot Co.), 240 parts of the epoxidized oil from Example XI and parts of the epoxidized oil from Example XIII to form a mill paste as above. To this mill paste was added 410 parts of the partial ester of Example IV and parts Cellosolve Acetate to make the final enamel. The enamel when cast as a thin film, air dried or conventionally'baked, gave a glossy, hard resistant coating.

(D) White enamel 500 parts Rutile Titanium Dioxide (Du Pont R-61O or equal), 15 parts of a silica product marketed as Cabosil M-S by Cabot Company, 40 parts of theacetate of the mono ethyl ether of ethylene glycol and 330 parts of the partial ester described in Example IV were mixed and ground in a conventional manner on a three roller mill. To this grinding paste was added 222 parts of the epoxidized oil described in Example XIII and 8 parts of the acetate of the mono-ethyl ether of ethylene glycol. This enamel was 78.7% solids and had a P.V.C. of 20.4%. Cured films had a 60 gloss of 92% after air drying or conventional baking as herein described.

Essentially these formulations provide for improved economics of solvent usage, formulating versatility, ease of handling, and higher solids levels without seed formation in applied films having improved color retention, and other improved and beneficial properties.

To show by data, some improved properties of dried films using the partial esters and epoxy materials of the above examples, the following tables are given. Table I concerns air dry film properties of several of the many possible combinations and Table II concerns baked film properties of similar combinations.

TABLE I..AIR DRY FILMS Partial Wt. Wet Non- Tack 24 Hr. Example Ester Epoxy Partial Wt. Percent Film Trans. Free Sward N0. Ex.N0. Ex. No Ester Epoxy N.V. Thick., Time, Time, Hard.

Solids Mils Min. Min.

TABLE IL-BAKED FILMS Bake Partial Epoxy Wt. Wt. Percent Wet Film Schedule Hot Sward Example N0. Ester Ex. No. Partial Epoxy N.V. Thick, mrn.at Hard Hard Ex. N0. Ester Mils 3% 30 F. XIII 30 24 3 250 Ex. 44 XIII 30 30 3 250 Ex. 38 XIII 27 32.4 3 250 Ex. 35 24 33.5 g 250 5. 14 12 250 x. 52 XIII 12 12 3 250 Ex. 52 X111 12 3 250 Ex. 43 XIII 24 24 3 250 Ex. 54 XIII 24 24 3 250 Ex. 54 XIII 12 15 3 250 Ex. 35 5 ii 3 3 28 I 56 2 52 XIII 12 9 3 250 E; 52 XIII 12 12 3 250 Ex. 40 XIII 12 15 3 250 Ex. 18 XI 12 9.5 3 250 Ex. 20 g 12 13 g 1 314. 55 12 25 x. 45 XII 12 12 3 250 Ex. XII 12 15 3 250 Ex. 25 XIII 12 9 3 250 EX. 40 XIII 12 12 3 250 Ex. 48 XIII 12 15 3 250 Ex. 45 III 12 12 3 250 Ex. 45 M11 12 6 75 3 250 Ex. 25 XIv 5 g? 12{ g 75 3 250 vo. 30 12 g 75 3 250 vs. 12 1g 75 3 250 45 54 12{ 6 75 3 250 25 gt? 12 g 75 3 250 32 12 g 75 3 250 35 XIII 12 12 73 3 250 Ex. 45 12 1g 75 3 250 Ex. 12 g 75 3 250 v.o. 25 {ggn 12 g 75 3 250 vo 32 12 6 75 3 250 V.G. 40

Listed in the columns in Table I from left to right are the example numbers; the example number of the partial ester or resinuous polycarboxylic acid, the example number of the epoxidized material, the weight of partial ester, the weight of epoxidized material, the percent solids of the partial acid-epoxidized material blend, the wet film thickness in mils, the non-transfer time in minutes, the tack free time in minutes and the 24-hour Sward hardness.

The films were drawn down approximately 1 hour after the partial ester, epoxidized material and solvent were blended. In some exemplary cases more than one epoxidized material was used with the partial esters. Catalysts were not found necessary to speed the cure of the preferred system. Some systems less preferred, but not specifically disclosed, may require catalysts such as benzyl trimethyl ammonium hydroxide to speed the cure. In other cases .005 to 2% phosphoric acid may serve as a curing catalyst.

Listed in Table II are the properties of partial esterepoxidized material films which were cured by baking at various schedules. The columns in Table II represent from left to right the example number, the example number of partial ester used, the example number of epoxidized material used, the weight of partial ester, the weight of epoxidized material, the percent solids of blend, the wet film thickness, the curing schedule and the Sward hardness of the cured films.

The epoxidized fatty esters and partial ester blends, as herein described, have a room temperature pot life varying from a few hours to several days depending upon the epoxidized fatty ester material, the partial ester and the percent solids of the blend. In general, the pot life is shortened by increasing the oxirane content of the epoxidized ester material, by increasing the reactivity of the partial ester or by increasing the percent solids in the blend of the partial esters and epoxidized ester material. In addition, the blends which contain chlorine groups appear the most reactive in normal air temperature cure while at baking temperatures above F. the presence of chlorine is not required for satisfactorily curing epoxidized fatty oils.

From the above, it will be apparent that the essential discovery lies in a manner of successfully utilizing the more economical polycarboxylic anhydrides in applying normally non-drying epoxy fatty ester compounds as clear or pigmented coating vehicles. However, some variations and modifications of this improvement in forming hard, durable, flexible films utilizing the non-drying epoxidized fatty esters by combination with the described resinous partial esters of condensation esterification polymers, may be made Without departing from the spirit and scope of the embodiment, given by way of the examples and expressed by the terms of the appended claims.

We claim:

1. A two-package coating system capable of forming a hard coating, said coating system consisting essentially of:

(a) in a first package, curable epoxidized fatty compound selected from the group consisting of epoxidized fatty oils, epoxidized monohydric alcohol esters of fatty acids, epoxidized polyhydric alcohol esters of fatty acids, epoxidized fatty nitriles, epoxidized fatty amides, epoxidized fatty amines, and epoxidized fatty alcohol-s; said fatty compound having 8-26 carbon atoms in the fatty radicals and an internal oxirane value of from 3% to 10%, and

(b) in a second package, polyester curing agent for said epoxidized fatty compound; said polyester curin g-agent having an acid value of at least 50; said polyester curing agent being esterification reaction product of polyhydric alcohol and polycarboxylic '1 1 acid wherein the esterification reaction mixture has an initial ratio of carboxyl to hydroxyl of 1-3 to 1; said reaction product comprising polyester of the formula:

wherein n is at least two, wherein R is polyhydric alcohol residue, and wherein R is polycarboxylic acid residue.

2. A coating system of the type described in claim 1 wherein said curable epoxidized fatty compound in said first package is monomeric epoxidized ester of fatty acid, said ester having 12 to 22 carbon atoms with internal oxirane in each fatty radical and 1 to carbon atoms in the alcohol radical, the oxirane value of said ester being at least 6%.

3. A coating system of the type described in claim 2 wherein from 50-150 parts of polyester curing agent are present per 100 parts of epoxidized fatty ester and wherein said polycarboxylic acid comprises chlorinated polycarboxylic acid.

4. Substrate coated with the cured filmobtained by mixing and drying the coating system defined in claim 2.

5. A two-package coating system capable of forming a hard coating, said coating system consisting essentially of:

(a) in a first package, solvent and curable monomeric epoxidized ester of fatty acid; said ester having 12 to 22 carbon atoms with internal oxirane in each fatty radical and 1 to 10 carbon atoms in the alcohol radical, the oxirane value of said ester being from 6% to 10%, and

(b) in a second package, solvent and polyester curing agent for said epoxidized ester; said polyester curing agent having an acid value of atleast 50; said polyester curing agent being esterification reaction product of polyhydric alcohol and polycarboxylic acid wherein the es-terification reaction mixture has an initial ratio of carboxyl to hydroxyl of about 1.8 to 1 and wherein said polycarboxylic acid comprises chlorinated polycarboxylic acid; said reaction product comprising polyester of the formula:

wherein n is at least two, wherein R is polyhydric alcohol residue, and wherein R is polycarboxylic acid residue, (c) from 50-150 parts of polyester curing agent being present per 100 parts of epoxidized fatty ester. 6. A two-package coating system capable of air drying, said system comprising first and second packages:

(a) in a first package, curable epoxidized fatty ester having 8 to 26 carbon atoms in the fatty radicals and an internal oxirane value of from 3% to 10%, and (b) in a second package, polyester curing agent for said epoxidized fatty ester; said curing agent having an acid value of at least 50; said curing agent being reaction product of polyhydric alcohol and polycarboxylic acid, said reaction product comprising polyester of the formula:

wherein n is at least two, wherein R is polyhydric alcohol residue and R is polycarboxylic acid residue;

said curing agent being prepared from an esterification reaction mixture having an initial ratio of car,-

boxyl to hydroxyl of from 13 to 1; said reaction mixture containing hexachloroendomethylene tetrahydrophthalic acid.

7. A coating system of the type described in claim 6 wherein from 50 to 150 parts of curing agent are present per parts of epoxidized fatty ester and wherein said fatty ester is fatty glycerol ester having an internal oxirane value of at least 6%.

8. A coating system of the type described in claim 7 wherein said polyhydric alcohol comprises pentaerythritol.

9. A coating system of the type described in claim 8 wherein said polycarboxylic acid is a mixture of phthalic anhydride and hexachloroendomethylene tetrahydrophthalic acid and wherein said curing agent has an acid value of at least about 160. v

10. Substrate coated with the cured film obtained by mixing and drying the coating system defined in claim 6.

11. A two-package coating system capable of air drying to form a hard, mar-resistant, durable coating, said coating system consisting essentially of first and second packages:

(a) in a first package, curable epoxidized ester of C C fatty acid, said curable epoxidized ester having an internal oxirane value of 3% to 10%, and

(b) in a second package, polyester curing agent for said epoxidized ester; said polyester curing agent having an acid value of at least 50; said polyester curing agent being esterification reaction product of pentaerythritol, phthalic anhydride and hexachloroendomethylene tetrahydrophthalic acid wherein the esterification reaction mixture has an initial ratio of carboxyl to hydroxyl of l3 to 1; said esterification reaction product comprising, as the predominant species, polyester of the formula:

wherein n is at least two, wherein R is polyhydric alcohol residue, and wherein R is polycarboxylic acid residue.

12. A coating system of the type defined in claim 11 wherein said initial ratio of carboxyl to hydroxyl is about 1.8 to 1 and wherein said first and second packages each contain solvent.

13. Substrate coated with the cured film obtained by mixing and drying the two-package coating system defined in claim 11, from 50-150 parts of said polyester curing agent being present per 100 parts of epoxidized ester.

14. A two-package coating system capable of drying to form a hard, mar-resistant, durable coating, said coating composition consisting essentially of first and second packages:

(a) in a first package, curable epoxidized fatty compound selected from the group consisting of epoxidized fatty oils, epoxidized monohydric alcohol esters of fatty acids, epoxidized polyhydric alcohol esters of fatty acids, epoxidized fatty nitriles, and epoxidized fatty alcohols, said fatty compounds having 8 to 26 carbon atoms in the fatty radicals and an internal oxirane value of 6% to 10%, and

(b) in a second package, polyester curing agent for said epoxidized fatty compounds; said curing agent having an acid value greater than 50; said polyester curing agent being the esterification reaction product of polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, glycerol, trimethylolethane, trimethylolpropane, sorbitol, pentaerythritol, dipentaerythritol, and tripentaerythritol, and at least one polycarboxylic acid selected from the group consisting of phthalic acid, phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalie anhydride, hexachloroendomethylene tetrahydrophthalic anhydride, hexachloroendomethylene tetrahydrophthalic acid, maleic acid, maleic anhydride, trimellitic acid, trimellitic anhydride, tetrachlorophthalic acid, tetrachlorophthalic anhydride, monochloro- 13 phthalic acid, monochlorophthalic anhydride, hexachlorophthalic acid and hexachlorophthalic anhydride, said esterification reaction product containing as the predominant species, polyester of the formula:

wherein n is at least two, wherein R is polycarboxylic acid residue and R is polyhydric alcohol residue, and wherein the esterification reaction mixture has an initial ratio of carboxyl to hydroxyl of 1-3 to 1.

15. A coating system of the type described in claim 14 wherein at least a portion of the polycarboxylic acid is hexachloroendomethylene tetrahydrophthalic acid and wherein said coating system is capable of air drying.

16. Polyester having an acid value of at least 50, said polyester being the esterification reaction product of polyhydric alcohol and polycarboxylic acid wherein the esterification reaction mixture has an initial ratio of carboxyl to hydroxyl of 1-3 to 1; said reaction product containing, as the predominant species, polyester of the formula:

wherein n is at least two, wherein R is polyhydric alcohol residue and wherein R is polycarboxylic acid residue, said polycarboxylic acid comprising chlorinated polycarboxylic acid.

17. Polyester of the type described in claim 16 wherein said polycarboxylic acid comprises hexachloroendomethylene-tetrahydrophthalic acid.

18. Polyester of the type described in claim 16 wherein said reaction mixture is a mixture of pentaerythritol, phthalic anhydride and hexachloroendomethylene tetrahydrophthalic acid and the initial ratio of carboxyl to hydroxyl is about 1.8 to 1.

References Cited by the Examiner UNITED STATES PATENTS 2,720,500 10/1955 Cody 26022 2,912,409 11/ 1959 Nischk et al. 260 2,959,559 11/1960 Delius 26075 3,027,357 3/1962 Stickle 26078.3 3,031,434 4/1962 Radlove 26078.4 3,043,717 7/1962 Budde 26022 3,050,480 8/1962 Budde 26022 3,086,949 4/ 1963 Chatfield 26022 3,098,052 7/1963 Schmitz et a1. 26022 FOREIGN PATENTS 569,634 1/1959 Canada. 806,730 12/ 1958 Great Britain.

LEON I. BERCOVITZ, Primary Examiner.

MILTON STERMAN, JAMES A. SEIDLECK,

Examiners.

Claims (1)

1. A TWO-PACKAGE COATING SYSTEM CAPABLE OF FROMING A HARD COATING, SAID COATING SYSTEM CONSISTING ESSENTIALLY OF: (A) IN A FIRST PACKAGE, CURABLE EPOXIDIZED FATTY COMPOUND SELECTED FROM THE GROUP CONSISTING OF EPOXIDIZED FATTY OILS, EPOXIDIZED MONOHYDRIC ALCOHOL ESTERS OF FATTY ACIDS, EPOXIDIZED POLYHYDRIC ALCOHOL ESTERS OF FATTY ACIDS, EPOXIDIZED FATTY NITRILES, EPOXIDIZED FATATY AMIDES, EPOXIDIZED FATTY AMINES, AND EPOXIDIZED FATTY ALCOHOLS; SAID FATTY COMPOUND HAVING 8-26 CARBON ATOMS IN THE FATTY RADICALS AND AN INTERNAL OXIRANE VALUE OF FROM 3% TO 10%, AND (B) IN A SECOND PACKAGE, POLYESTER CURIG AGENT FOR SAID EPOXIDIZED FATTY COMPOUND; SAID POLYESTER CURIN GAGENT HAVING AN ACID VALUE OF AT LEAST 50; SAID POLYESTER CURING AGENT BEING ESTERIFICATION REACTION PRODUCT OF POLYHYDRIC ALCOHOL AND POLYCARBOXYLIC ACID WHEREIN THE ESTERIFICATION REACTION MIXTURE HAS AN INITIAL RATION OF CARBOXYL TO HYDROZXYL OF 1-3 TO 1; SAID REACTION PRODUCT COMPRISING POLYESTER OF THE FORMULA: