MXPA97000464A - Composition of coating with low organic volatile content for finishing automovi - Google Patents

Abstract

The present invention relates to a coating for automotive finishing applications having a volatile organic content not exceeding 3.0 pounds per gallon, containing a hydroxyl functional polyester and a polyisocyanate curing agent. The functional hydroxyl polyester is prepared from reactants containing: (A) from about 15 percent to about 50 percent of a polyol or mixture of polyols, each having a formula molecular weight of from about 50 to about 2,000; B) from about 15 percent to about 50 percent of a long chain monocarboxylic acid or mixture of acid acids, each having about 6 to 24 carbon atoms, and (C) from about 15 percent to about 30 percent of dicarboxylic acid 1, 4-cyclohexane, the percentages are based on the total passage of the ractants used to prepare the polyester. The coating composition for finishing is particularly suitable as a transparent coating on a pigmented base coat

Description

COMPOSITION OF COATING WITH LOW ORGANIC CONTENT VOL TIL FOR FINISHING AUTOMOBILES BACKGROUND OF THE INVENTION The present invention relates to polyester-based polyester-based coating compositions with polyisocyanates for automotive finishing applications. One of the main objectives of the coatings industry at present is the formulation of coating compositions that not only have excellent physical properties and appearance but also that are formulated with minimal amounts of volatile organic solvents. This is especially true in the automotive coatings area where the so-called "attractive type" finishes of an automobile is an important feature but difficult to achieve with compositions that have minimal amounts of organic solvents. In the field of automotive finishing coatings, there is also a requirement that the coating composition be capable of curing at room temperature or at most at a stage of forced heating at a slightly elevated temperature. Transparent coatings for automotive finishing have a particular challenge since not only the appearance and the content of volatile organic substances have to satisfy certain rigid standards but also the transparent coating must not yellow since this makes the pigmented base coat finish unattractive . Therefore, there is a need for a clear coating composition for use in automotive finishing having a low content of volatile organic substances, which not only possesses excellent physical properties and appearance, but also meets stringent environmental standards as regards to volatile organic solvent emissions. EP 0 036 975 discloses polyester polyalcohols for use in coating compositions with polyisocyanates. Polyester polyalcohols are produced from various acids, but this document does not disclose a long chain combination of monocarboxylic acids and 1,4-cyclohexanedicarboxylic acid. Patent EP 0145 006 describes polyester polyalcohols produced from aromatic acids. The coatings produced from these polyesters are cured with aminoplasts, instead of with polyisocyanates. Patent EP 375 823 describes polyester polyalcohols which are cured with polyisocyanates. Polyester polyalcohols are produced from hexanoic acid or di-ero acid.

SUMMARY OF THE INVENTION According to the present invention, there is provided a coating composition for automotive finishing having a content of volatile organic substances not exceeding 0.36 kg / liter, comprising: A. a functional polyester hydroxyl prepared from reagents consisting of: (a) from about 15 percent to about 50 percent of a polyalcohol or mixture of polyalcohols, each having a molecular weight according to the formula of about 50 to about 2,000; (b) from about 15 percent to about 50 percent of a long chain monocarboxylic acid or mixtures of monocarboxylic acids, each having from 6 to 24 carbon atoms; (c) from about 15 percent to ~ about 30 percent 1,4-cyclohexanedicarboxylic acid; the percentage being based on the total weight of reagents used to prepare the polyester and B. a polyisocyanate curing agent.

DETAILED DESCRIPTION OF THE INVENTION The automotive finishing coating compositions of the present invention contain a hydroxyl functional polyester and a polyisocyanato-Co curing agent, or a hydroxyl functional polyester, also called polyester polyol, has been established in general. can prepare by _ polyesterification of a polyalcohol with a carboxylic acid.

Specifically, the hydroxyl functional polyester of the present invention is prepared from about 15 percent to about 50 percent of a polyalcohol or mixtures of polyalcohols, each having a molecular weight according to the formula ranging from about 50 to about 2,000. Preferably the amount of polyalcohols varies between about 20 percent and about 45 percent and more preferably between about 30 percent and about 40 percent, based on the percentages in the total weight of reagents used in the preparation of the polyester. Normally, the polyalcohol is a diol or triol, although polyalcohols of higher functionality can be used. Preferably, the polyalcohol has a molecular weight according to formula of about 75 to about 1000 and more preferably about 100 to about 300. Examples of suitable polyalcohols include ethylene glycol, diethylene glycol, glycerin, trimethylpentane diol, cyclohexane diol, 1, 6-hexanediol, trimethylolpropane, pentaerythritol, neopentyl glycol, 2-methylolpropane diol, ethoxylated trimethylolpropane and mixtures thereof. In addition to the above-described polyalcohol, the hydroxyl-functional polyester is prepared from about 15 percent to about 50 percent of a long-chain monocarboxylic acid or mixture of such acids, each having from 6 to 24 carbon atoms, preferably 12 to 20 carbon atoms. It is not convenient to use monocarboxylic acids having more than 24 carbons since these materials, which tend to be softer and waxy, worsen the appearance of the cured film. Preferably, the amount of long chain monocarboxylic acid varies between • about 20 percent to about 45 percent, more preferably from about 30 percent to about 40 percent, based on the percentage in the total weight of reagents used in the polyester preparation. Examples of suitable long chain monocarboxylic acids include hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, lauric acid, isostearic acid, stearic acid, hydroxystearic acid, flaxseed fatty acid, oleic acid, octadecanoic acid, tetradecanoic acid, eicosanoic acid and mixtures thereof. Preferably, the long chain monocarboxylic acid is isostearic acid. A mixture of isostearic acid and lauric acid is also preferred. Another important ingredient used in the preparation of the hydroxyl functional polyester of the present invention is 1-cyclohexanedicarboxylic acid. The 1,4-cyclohexanedicarboxylic acid is used in an amount of from about 15 percent to about 30 percent, more preferably from about 20 percent to about 25 percent, based on the percentages in the total weight of reagents used in the preparation of polyester. This material is marketed by Eastman Kodak as EASTMAN® 1,4-CHDA and sold as a mixture of isomers. The one used herein is preferably a high purity product which is approximately 80:20 cis: trans. You can also use the "R" grade which is approximately 60:40 cis: trans. Acid 1, -cyclohexane dicarboxylic acid is considered important to achieve good hardness, durability, ultraviolet light stability and faster tack time in the coating film. The reagents used to prepare the hydroxyl-functional polyester may additionally contain a mono- or dicarboxylic acid or anhydride thereof different from the long-chain monocarboxylic acid described above. Among the carboxylic acids or anhydrides which are useful are, for example, adipic acid, succinic acid, suberic acid, pimaric acid, isophthalic acid, azelaic acid, sebacic acid, maleic acid, glutaric acid, dodecanoic acid, terephthalic acid, chlordenedic acid, carboxylic cyclohexane acid, hexahydrophthalic anhydride or mixtures thereof. The mono or dicarboxylic acid or anhydride thereof, when used, generally ranges from about 0 percent to about 50 percent, based on the percentage in total weight of reagents used in the preparation of the polyester. The ingredients used to prepare the hydroxyl functional polyester may also include minor amounts of monobasic acids such as benzoic acid or acetic acid. In addition, smaller amounts of higher polycarboxylic acids such as trimellitic acid and tricarbalilic acid may be employed. Lower alkyl esters of these acids such as dimethyl glutarate and dimethyl terephthalate can also be used.

The polyesterification reaction is carried out following techniques well known to those skilled in the chemistry of polymers and will not be discussed in detail here. Generally, the reaction can be carried out by combining the ingredients and heating to a temperature of about 160 ° C to about 220 ° C, often referred to as "hot melt" conditions. It is important to note, however, that the polyesterification reaction is preferably carried out under azeotropic conditions using a solvent which forms a good azeotrope with water, for example xylene or 1-decene. Preferably, xylene is used. The amount of azeotropic solvent generally ranges from about 3 percent to about 4 percent, based on the total weight of reagents used to prepare the polyester. Xylene is typically used in an amount of about 3 percent. During the course of polyesterification, most of the polyester is formed in a temperature range from about 170 ° C to about 220 ° C, which is preferred because lower temperatures help to prevent turbidity of the final product. The temperature during the entire course of the reaction generally varies between about 160 ° C to about 220 ° C. Polyesterification is considered complete when an acid value of less than 4 mg KOH / gram of polymer determined by the known potentiometric titration techniques is obtained. The hydroxyl functional polyesters used in the formulation of the claimed car topcoat compositions generally have a hydroxyl number ranging from about 100 to about 300, preferably from about 175 to about 275 and more preferably from about 200 to about 260 mg of KOH / gra or polymer determined by the aforementioned potentiometric techniques. The aforementioned hydroxyl functional polyesters generally have a number average molecular weight ranging from about 800 to about 3000, preferably from about 900 to about 1700, the molecular weight being determined by gel permeation chromatography (GPC) using polystyrene as pattern. It should be noted that 2-hydroxyethyl ethylene urea can be used in the preparation of the hydroxyl-functional polyester, in the same way a monocarboxylic acid will be used for its ability to terminate the chain. This material is marketed by Sartomer Company as HEEU. As one skilled in the art can easily account for, a catalyst is typically used to accelerate the polyesterification reaction. Normally, butyl stannic acid or dibutyltin oxide is used. The catalyst is optional, and if used, the amount can vary widely. When used, the amount typically ranges from about 0.1 percent to about 0.25 percent, based on the percentage of the total weight of reagents used in the polyester preparation. The polyisocyanate that is used to cure (crosslink) the hydroxyl functional polyester can be selected from a variety of organic materials including aliphatic, cycloaliphatic as well as aromatic polyisocyanates, including mixtures thereof. Typically, the polyisocyanate is a diisocyanate. Examples of suitable aliphatic diisocyanates include 1,4-tetramethylene diisocyanate and 1,6-hexamethylene diisocyanate. Examples of suitable aromatic diisocyanates are 4,4'-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and toluene diisocyanate. Examples of suitable cycloaliphatic diisocyanates include 1,4-cyclohexyl diisocyanate, isophorone diisocyanate, 4,4'-methylene-bis (cyclohexyl isocyanate). Triisocyanates such as aliphatic triisocyanate TMXDI-IMP of CYTEC may also be used. Isocyanurates and biurets of the diisocyanates described above can also be used. Preferably, the polyisocyanate curing agent of the present invention is an isocyanurate. More preferably, the isocyanurate is a mixture of • Isocyanurates, especially a mixture of isocyanurate of isophorone diisocyanate (IPDI) and isocyanurate of hexamethylene diisocyanate (HDI). The blend generally includes from about 5 percent to about 50 percent IPDI and from about 50 percent to about 95 percent HDI, preferably from about 20 percent to about 80 percent IPDI and about 40 percent to approximately 60 percent HDI. More preferably the mixture contains from about 25 to about 30 percent of IPDI and about 70 to about 75 percent of HDI. The amount of hydroxyl functional polyester and polyisocyanate curing agent in the claimed automobile finish coating composition is such that the ratio of hydroxyl to isocyanate equivalents ranges from about 1: 0.5 to about 1: 2.5, preferably from about 1: 1 to about 1: 2 and more preferably from about 1: 1.5 to about 1: 1.8. The finished coating compositions of claimed automobiles have the particular advantage that they carry a minimum amount of volatile organic solvent (VOC) which generally does not exceed 0.36 kg / liter, preferably does not exceed 0.30 kg / liter and more preferably does not exceed 0.25 kg / liter. The claimed coating compositions are generally multi-container coating compositions with the hydroxyl-functional polyester in one of the packages and the polyisocyanate curing agent in another separate container. Other ingredients of the composition can be included in either of the two containers as desired. Preferably, the claimed coating compositions are three-pack compositions with the hydroxyl-functional polyester in one of the containers, the curing agent in a second container and with a third container containing an accelerator to promote the rapidity of the curing reaction between the hydroxyl and isocyanate groups. Examples include materials such as dibutyl tin dilaurate and dibutyl tin diacetate. A material for prolongation of shelf life, for example 3-ethyl-2,4-pentanedione, pentanedione or tertiary butyl acetoacetate, is also preferably contained in the third container. The other ingredients may be in any of the containers, as desired. The claimed coating compositions typically have a resin solids content ranging from about 50 percent to about 90 percent determined at 110 ° C for 1 hour. Although the claimed coating compositions are preferably clearcoat compositions that can be used as a clear topcoat over a pigmented basecoat, the coating compositions can also be pigmented with a variety of pigments and used as a colored basecoat or as a topcoat of finishing, without transparent layer. Alternatively, the claimed coating compositions can be used as primers if desired. A variety of pigments well known to those skilled in the art can be used, including inorganic pigments such as titanium dioxide, silica, iron oxide, talc, mica, carbon black and zinc oxide. Organic pigments can also be used. In addition, metallic pigments such as aluminum flakes and metallic effect pigments such as pearlescent pigments such as those marketed by Mearl Corp. can be used. The claimed coating compositions are typically prepared in a suitable solvent to facilitate ~ the formulation and application. Suitable solvents include aliphatic solvents such as NAPTHA VM & P, aromatic petroleum distillates; cycloaliphatic solvent such as cyclohexane; ketones such as methylethyl ketone, methyl isobutyl ketone and methyl amyl ketone; alcohols such as ethyl alcohol, propyl alcohol and diacetone alcohol; acetates such as butyl acetate and hexyl acetate; and mono- and di-alkyl ethers of ethylene, propylene and diethylene glycol, such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, propylene glycol monomethyl ether, dipropylene glycol ether and propylene glycol monomethyl ether acetate. The claimed coating compositions may also contain a variety of conventional additives including surfactants, antioxidants, ultraviolet light absorbing agents, stabilizers, rheology control agents, coalescing agents and the like. The above described packages containing the ingredients of the coating composition are typically combined together by gentle agitation before application. The coating compositions are typically applied by spraying although other well-known modes of application may be employed. As mentioned above, the coating composition is typically applied as a clear topcoat over the pigmented basecoat, including a variety of conventionally known basecoats. The clear topcoat is generally applied at a uniform film thickness ranging from about 0.05mm to about 0.08mm. The coating compositions can be cured under ambient or slightly elevated temperatures by heating to a temperature of about 30 ° C to about 60 ° C. The coating compositions of the present invention not only do not contain a minimum of volatile organic solvent but also exhibit excellent appearance and physical properties including brightness, hardness and image sharpness. In addition, the coatings have a good tack time after application. The following examples are illustrative of the invention and are not to be construed as limiting thereof.

EXAMPLES The following examples illustrate the preparation of various polyesters according to the present invention, their formulation in automobile finishing coating compositions and their evaluation.

Preparation of polyesters Examples 1 to 8 given below show the preparation of a variety of polyesters with hydroxyl function according to the present invention. For the preparation of each polyester, the following procedure was followed: Materials (A), (B), (C), (D), (E), (F) and (G), when used, were introduced into a round-bottomed, four-neck, 3-liter capacity flask, equipped with a motor-driven stainless steel paddle stirrer, a thermocouple to record the temperature of the batch, a Dean-Stark trap for water, connected to a condenser to collect the distillate released, and a nitrogen spray tube. The synthesis of Example 2 was carried out using conditions of azeotrope formation with xylene (3% solids). Heat was applied to a Glas-Col column fitted with heating mantle and the temperature was gradually increased to approximately 220 ° C and maintained at an acid number of less than four. The remaining examples were prepared by simply combining the ingredients and gradually increasing the temperature to about 220 ° C. (Conditions of "hot fusion").

Example 1 Preparation of polyester using flaxseed fatty acid Weight Weight Loading Reagents (grams) Equivalents (%) A 1,4-cyclohexane dicarboxylic acid 344.0 4.00 23, 6 B Flaxseed fatty acid 575.4 2.00 39.4 Trimethylolpropane 540.0 12.0 37.0 D Triphenyl phosphite 3.70 E Dibutyltin oxide 2.50 Example 2 Preparation of polyester using isostearic acid Weight Weight Loading Reagents (g: bouquets) Equivalents (%) A 1, 4-cyclohexane dicarboxylic acid 344.0 4.00 23.7 B B A Acciiddoo iissooeess ¡tteeáarr • iiccoo 5 56688,, 00 2,00 39,1 C Trimethylolpropane 540,0 12,0 37,2 D Triphenyl phosphite 3, 60 E Dibutyl .1 tin oxide 2, 60 Example 3 Preparation of polyester using isostearic acid and cyclohexane carboxylic acid Weight Weight Loading Reagents (g: bouquets) Equivalents (%) A 1, 4-cyclohexane dicarboxylic acid 344.0 4.00 26.5 B Isostearic acid 284.0 1.00 21.9 C Trimethylolpropane 540.0 12.0 41.7 D Cyclohexanecarboxylic acid 128.2 1.00 9.89 Triphenyl phosphite 3.30 Dibutyltin oxide 2.30 Example 4 0 Preparation of polyester using pentaerythritol and trimethylolpropane Loading Reagents (grams) Equivalents (%) A 1,4-cyclohexane dicarboxylic acid 344.0 4.00 27.5 0 B Isostearic acid 568.0 2.45 45.5 C Trimethylolpropane 275.0 6.11 22, 0 5 D Pentaerythritol 73.40 1.42 5.00 E Triphenyl phosphite 3.20 0 F Dibutyltin oxide 2.20 f '* - Example 5 Preparation of polyester using a mixture of isostearic acid and lauric acid 0 Weight Weight Loading Reagents (grams) Equivalents (%) A 1,4-cyclohexane-5-dicarboxylic acid 344.0 4.00 29.6 B Acid isostearic 284.0 1.00 24.4 Trimethylolpropane 335.3 7.50 28.8 D Lauric acid 200.00 1.00 17.2 Triphenyl phosphite 3.00 Dibutyltin oxide 2.10 Example 6 Preparation of polyester using lauric acid Weight Weight Loading Reagents (grams) Equivalents (%) A Acid 1, -cyclohexane dicarboxylic 344, 0 4, 00 31, 9 B Lauric acid 400, 0 2, 00 37, 1 Trimethylolpropane 335.3 7.50 31.1 D Triphenyl phosphite 2.80 Dibutyl tin oxide 1, 90 Example 7 Preparation of polyester using isostearic acid, lauric acid and cyclohexane carboxylic acid Weight Weight Loading Reagents (grams) Equivalents (%) A 1,4-cyclohexane dicarboxylic acid 344.0 4.00 25, 9 B Isostearic acid 284.0 1.00 21.4 C Trimethylolpropane 536.4 12.0 40.4 D Lauric acid 100.00 0.50 7.53 E Carboxylic acid cyclohexane 64.1 0.50 4.82 F Triphenyl phosphite 3.50 G Dibutyl tin oxide 2.40 Example 8 Preparation of polyester using ethoxylated trimethylolpropane Weight Weight Load Reagents (grams) Equivalents (%) A Acid 1, -cyclohexane dicarboxylic 191.0 2.22 17.4 B TP-30 * 593.3 6, 67 53.9 Isostearic acid 315.5 1.11 28.7 D Triphenyl phosphite 2.70 E Dibutyl tin oxide 2.00 * Ethoxylated trimethylolpropane marketed by Perstorp AB Preparation of clear coating compositions Examples 9 to 11 below illustrate the preparation and evaluation of clearcoat compositions with hydroxyl functional polyesters of the above Examples 1 to 8. The ingredients used in the coating formulations are explained in the table immediately following the formulations. Each of the coating compositions has a theoretical VOC content (volatile organic solvents) of approximately 2.1.

Example 9 Ingredients Percent by weight 5 Polyalcohol container Polyester of Example 2 31, 50 TEGO 425 or, 30 EKTASOLVE EEP 7, 07 TINUVIN 384 1, 83 0 Dibutyltin dilaurate or, 04 Subtotal 40.74 Hardener container "" "" DESMODUR N 3400 33, 66 5 T-1890 16, 02 Methyl amyl ketone 3, 80 Subtotal 53,48 Additive container 0 Dibutyltin dilaurate 0.08 Pentanenedione 5.70 Subtotal 5.78 TOTAL 100.00 Example 10 Ingredients Percent by weight Polyalcohol container Polyester of Example 6 27, 45 SIL ET 7500 0, 69 DOWANOL AMP 9, 15 Methyl amyl ketone 6, 53 '' EXXATE 600 2, 99 SOLVESSO 100 1/87 TINUVIN 384 1, 65 Dibutyltin dilaurate or, 70 Pentanedione 3, 97 Subtotal 54.39 Hardener container DESMODUR N 3400 30.90 T-1890 14.72 Subtotal 45, 62 TOTAL 100.00 Example 11 Ingredients Percent by weight Polyalcohol container Polyester of Example 8 27.47 SILWET 7500 0, 69 DOWANOL AMP 9.15 Methyl amyl ketone 6, 53 EXXATE 600 2, 99 SOLVESSO 100 1 87 TINUVIN 384 i, 65 Dibutyltin dilaurate or, 07 Pentanedione 3, 97 Subtotal 54,39 Hardener container DESMODUR N 3400 30, 90 T-1890 14, 72 Subtotal 45, 62 TOTAL 100, 00 Explanation of the ingredients: Steel panels Marketed by Advanced Coating Technologies, Inc. Hillsdale, MI as cold rolled steel ACT B952 DIW: polished DP 40 / DP401 A filler made by mixing 1 volume of epoxy primer DP 40/1 volume of epoxy primer DP 401. All products are marketed by PPG industries, Inc. PPG finishes. DBU16642 / DRR1170 A base layer made by mixing Deltron® DBU16642 basecoat and 1.5 volumes of DRR 1170 reagent reducer. All products are marketed by PPG Industries, Inc. PPG Finishes. TINUVINR 384 UV absorption agent marketed by Ciba-Geigy Corporation, Hawthorne, New York.

EK ASOLVER EEP Commercial solvent from Eastman Chemical Products, Kingston, T N. Methyl a il ketone Commercial solvent from Union ide Chemical and Plastics Corporation, Danbury, CT. MP DOWANOLP Acetate Commercial solvent from Eastman Chemical Products, Kingston, TN TEGO 425 A commercial surfactant compound from TEGO Chemie Service USA, a Division of Goldschmidt Chemical Corp., Hopewell, VA.

Dibutyltin dilaurate A commercial catalyst from ATOCHEM North America, Philadelphia, PA. DESMODURR N 3400 A commercial polyisocyanate from Miles Inc., Pittsburgh PA which is the isocyanurate of hexamethylene diisocyanate. T-1890 A commercial polyisocyanate from Hüls Chemische Werk Hüls AG, Mari, Germany, which is the isocyanurate of isophorone diisocyanate. Pentanedione Thinner and lifter, from Union ide Chemical and Plastics Corporation, Danbury, CT. SILWETK 7500 Commercial surfactant, from Union ide Chemical and Plastics Corporation, Danbury, CT. SOLVESSOR 100 Commercial solvent, from Exxon Chemical Co., Houston, TX. EXXATER 600 Commercial solvent, from Exxon Chemical Co., Houston, TX. The coatings were applied on 32 gauge steel panels pre-treated with zinc phosphate. The panels were printed with DP40 / DP401, allowed to dry for 1 hour and then a base coat of DBU-16442 / DDR-1170 was applied. The base coat was allowed to dry for 30 minutes, then the clear coat was applied. Each of the coated panels was allowed to dry overnight at room temperature before testing.

Test methods The BRIGHTNESS at 20 ° was measured with a brightness meter Byk Gardner Glossgard lia. The SWARD HARDNESS was measured using a Sward Rocker. HARDNESS TO THE PENCIL was measured using Eagle-Tortoise pencils.

The pencil hardness was measured by the resistance of the coating to a pencil notch. The hardness scale varies from 4B, which indicates a relatively soft coating, and increasing up to 10H, which indicates a relatively hard coating. STICKING TIME was measured by determining the time in minutes (hours) from when the coating is first applied until the time when the coating does not give a sticky feeling by light pressure with the index finger on the surface of the coating. Properties Hardness Time Hardness stickiness Sward to pencil Example (hours) Brightness at 20 ° (24 h.) (24 h.) 9 2, 0 87 12 6B 10 2, 5 85 6 5B 11 2, 75 87 2 6B

Claims (22)

1. CLAIMS 1. A car topcoat composition having a content of volatile organic substances not exceeding 0.36 kg / liter comprising: A. a polyester with a hydroxyl function prepared from reagents consisting of: a) about 15 percent to about 50 percent of a polyalcohol or mixture of polyalcohols, each having a molecular weight according to the formula of about 50 to about 2000; b) from about 15 percent to about 50 percent of a long chain monocarboxylic acid or mixture of monocarboxylic acids, each having from 6 to 24 carbon atoms; c) from about 15 percent to about 30 percent 1,4-cyclohexanedicarboxylic acid; the percentages being based on the total weight of the reagents used in the preparation of the polyester and B. a polyisocyanate curing agent.
2. 2. The coating composition according to claim 1 wherein component A further comprises a mono- or dicarboxylic acid or anhydride thereof different from the long chain monocarboxylic acid of component (b).
3. 3. The coating composition according to claim 1 wherein the polyalcohol is selected from the group consisting of ethylene glycol, diethylene glycol, glycerin, trimethylpentane diol, cyclohexane diol, 1,6-hexane diol, trimethylolpropane, ditrimethylolpropane, neopentyl glycol, 2-methylol propane diol, 'pentaerythritol, ethoxylated trimethylolpropane and mixtures thereof.
4. 4. The coating composition according to claim 3 wherein the poly alcohol is trimethylolpropane.
5. 5. The coating composition according to claim 1 wherein the amount of polyalcohol varies from about 20 percent to about 45 percent.
6. 6. The coating composition according to claim 5 wherein the amount of polyalcohol varies from about 30 - * 'percent to approximately 40 percent.
7. 7. The coating composition according to claim 1 wherein the long chain monocarboxylic acid is selected from the group consisting of stearic acid, isostearic acid, hydroxystearic acid, lauric acid, flaxseed fatty acid, and mixtures thereof.
8. 8. The coating composition according to claim 7 wherein the long chain monocarboxylic acid is a mixture of isostearic acid and lauric acid.
9. 9. The coating composition according to claim 7 wherein the long chain monocarboxylic acid is isostearic acid.
10. 10. The coating composition according to claim 1 wherein the amount of long chain monocarboxylic acid ranges from about 20 percent to about 45 percent.
11. 11. The coating composition according to claim 10 wherein the amount of long chain monocarboxylic acid ranges from about 30 percent to about 40 percent.
12. 12. The coating composition according to claim 1 wherein the amount of 1,4-cyclohexane dicarboxylic acid varies from about 20 percent to about 25 percent.
13. 13. The coating composition according to claim 1 wherein the polyisocyanate is an isocyanurate or mixture of isocyanurates.
14. 14. The coating composition according to claim 13 wherein the isocyanurate is a mixture of the isocyanurate of isophorone diisocyanate and the isocyanurate of hexamethylene diisocyanate.
15. 15. the coating composition according to claim 1 wherein the content of volatile organic substances does not exceed 0.30 kg / liter.
16. 16. The coating composition according to claim 1 wherein the hydroxyl functional polyester has a hydroxyl number ranging from about 100 to about 300 mg KOH / gram of polymer.
17. 17. The coating composition according to claim 1 wherein the hydroxyl functional polyester has a number average molecular weight of about 800 to about 3000.
18. 18. The coating composition according to claim 1 wherein the ratio of equivalents of hydroxyl groups in the polyester polyol to isocyanate groups in the polyisocyanate ranges from about 1: 0.5 to about 1: 2.5.
19. 19. The coating composition according to claim 2 wherein the amount of mono- and di-carboxylic acid or anhydride thereof, which is different from the long-chain monocarboxylic acid, ranges from about 0 percent to about 50 percent.
20. 20. The coating composition according to claim 1 wherein the polyesterification reaction for preparing the hydroxyl functional polyester is carried out under azeotropic conditions at a temperature in the range of about 160 ° C to about 220 ° C.
21. 21. The coating composition according to claim 1 which is a pigmented coating composition.
22. 22. The coating composition according to claim 1 which is a clear coating composition.