KR102340547B1 - Oil paint composition for automobiles surface coating - Google Patents

Abstract

The present invention provides an oil paint for intermediate automobiles comprising 10 to 40 parts by weight of a polyester polyol resin, 5 to 30 parts by weight of a polyester-modified acrylic microgel resin, 1 to 15 parts by weight of an alkyd resin, and 5 to 30 parts by weight of a melamine resin. to the composition.

Description

Oil-based paint composition for automotive intermediates {OIL PAINT COMPOSITION FOR AUTOMOBILES SURFACE COATING}

[0001] The present invention relates to an oil-based paint composition for an automobile intermediate coating excellent in adhesion, repainting, chipping resistance and appearance characteristics of the prepared coating film.

In order to protect the surface of the vehicle body from the exterior and the external environment, it is common to perform electrodeposition painting, intermediate painting, base painting, and clear painting. For example, an electrodeposition paint is applied to a vehicle body and then cured, and an intermediate paint is applied and cured. Thereafter, it is a common automobile painting system to continuously coat a base coat and a clear coat on the intermediate coating layer and then harden them. In addition, in the automobile painting process as described above, a three-coat and two-bake (3C2B) painting method in which primary curing is performed after intermediate painting, and secondary curing after base coat and clear coat painting is common.

However, in order to reduce costs such as equipment investment cost, facility management cost and painting cost of the painting process and to improve the eco-friendliness of the paint, a three-coat, one-bake (3C1B) painting method, a mid-erasing type painting method, etc. have been proposed. The 3 coat 1 bake painting method consists of electrodeposition, intermediate coat, base coat, and clear coat. The base coat and clear coat are coated with wet on wet without primary curing after the intermediate paint is applied, but the intermediate paint is applied. to be. In addition, the half-finish coating method consists of electrodeposition, base, and clear coat, and is a coating method in which the intermediate coating itself is deleted and the intermediate function is realized in the base coating film.

In this regard, Japanese Patent Application Laid-Open No. 1996-290102 (Patent Document 1) discloses a wet-on-wet coating method by controlling the neutralization value of the base resin of the water-soluble intermediate paint and the neutralization value of the base resin of the water-soluble top coat. This is disclosed. The coating method of Patent Document 1 improved the gloss and image quality of the coated film surface by controlling the neutralization value of the base resin to prevent interlayer inversion or mixed layer phenomenon between the intermediate layer and the top coat layer. Since it is generally used, it is very difficult to control the interaction between the layers only with the difference in the neutralization of the base resin. Since the top coat permeates onto the surface, differences in the appearance characteristics of the prepared coating film may occur depending on the electrodeposition roughness.

Therefore, there is a need for research and development on an oil-based paint composition for automobile intermediates having excellent appearance characteristics, adhesion, repainting properties, chipping resistance, and the like of the prepared coating film.

Japanese Patent Laid-Open No. 1996-290102 (published on: 11.5. 1996)

Accordingly, the present invention provides an oil-based paint composition for an automobile intermediate coating having excellent appearance characteristics, adhesion, repainting properties, chipping resistance, and the like of the prepared coating film.

The present invention provides an oil paint for intermediate automobiles comprising 10 to 40 parts by weight of a polyester polyol resin, 5 to 30 parts by weight of a polyester-modified acrylic microgel resin, 1 to 15 parts by weight of an alkyd resin, and 5 to 30 parts by weight of a melamine resin. A composition is provided.

The oil-based paint composition for an automobile intermediate coating according to the present invention has excellent appearance characteristics, adhesion, repainting properties, chipping resistance, and the like of the prepared coating film. Due to this, the composition can be applied to the coating system of 3C1B can lower the manufacturing cost.

Hereinafter, the present invention will be described in detail.

As used herein, "weight average molecular weight" and "number average molecular weight" are measured by a conventional method known in the art, and may be measured by, for example, a gel permeation chromatograph (GPC) method. In addition, the "glass transition temperature" is measured by a conventional method known in the art, for example, it can be measured by differential scanning calorimetry (DSC). In addition, functional groups such as "acid value" and "hydroxyl value" may be measured by a method well known in the art, for example, may represent a value measured by a method of titration. In addition, the viscosity may be measured by a method well known in the art, for example, may represent a value measured by a Brookfield (Brookield) rotating spindle method (25 ℃, 50 rpm).

In addition, in this specification, "(meth)acryl" means "acryl" and/or "methacrylic", and "(meth)acrylate" means "acrylate" and/or "methacrylate" .

The oil-based paint composition for automotive intermediate use according to the present invention comprises 10 to 40 parts by weight of a polyester polyol resin, 5 to 30 parts by weight of a polyester-modified acrylic microgel resin, 1 to 15 parts by weight of an alkyd resin, and 5 to 30 parts by weight of a melamine resin. include

polyester polyol resin

The polyester polyol resin is the main resin of the composition including the same, and serves to form the appearance characteristics and mechanical properties of the coating film prepared through chemical bonding with the melamine resin.

The polyester polyol resin may be directly synthesized according to a known method, or a commercially available product may be used. For example, the polyester polyol resin may be a polymer produced by a condensation reaction between a polyol monomer and a carboxyl group-containing monomer.

The polyol monomer is, for example, ethylene glycol, propylene glycol, trimethylol propane, trimethylolethane, cyclohexanedimethanol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 1,4- hexanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, triethylolpropane, glycerin, pentaerythritol, 3-methylpentanediol, and mixtures thereof.

In addition, the carboxyl group-containing monomer is, for example, phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, succinic anhydride, isophthalic acid, azelaic acid, maleic anhydride, trimellitic anhydride, terephthalic acid, fumaric acid, adipic acid and mixtures thereof.

The polyester polyol resin may be modified with a polyisocyanate compound during the production of the polyester resin or after the esterification reaction. In this case, the polyisocyanate compound is, for example, isophorone diisocyanate (IPDI), trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, propylene diisocyanate, ethylene diisocyanate, 2,3 -Dimethylethylene diisocyanate, 1-methyl trimethylene diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclopentene diisocyanate, 1,2-cyclopentene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, 4,4-diphenylpropane diisocyanate, xylene diisocyanate, and 1,1; It may be at least one selected from the group consisting of 6,6-tetramethylhexamethylene diisocyanate.

In addition, the polyester polyol resin may have a hydroxyl value (OHV) of 50 to 200 mgKOH/g, or 80 to 140 mgKOH/g. When the hydroxyl value of the polyester polyol resin is less than the above range, the crosslinking density with the melamine resin is insufficient, resulting in a problem that the durability and chemical resistance of the prepared coating film are lowered. This may cause a problem in which chipping resistance is lowered.

The polyester polyol resin may have an acid value (AV) of 1 to 70 mgKOH/g, or 1 to 30 mgKOH/g. When the acid value of the polyester polyol resin is less than the above range, the curing reaction rate is lowered to cause a problem in that the hardness and appearance characteristics of the prepared coating film are lowered. Problems can arise.

In addition, the polyester polyol resin may have a number average molecular weight (Mn) of 1,000 to 10,000 g/mol, or 1,000 to 6,000 g/mol. When the number average molecular weight of the polyester polyol resin is less than the above range, the molecular weight is small and the mechanical properties of the prepared coating film are deteriorated. As the coating film becomes hard, a problem in which chipping resistance is lowered may occur.

The polyester polyol resin may have a glass transition temperature (Tg) of -30 to 30 °C, or -10 to 10 °C. When the glass transition temperature of the polyester polyol resin is within the above range, molecular fluidity is improved upon curing of the paint, and the paint appearance and curability are improved, so that the hardness and appearance characteristics of the prepared coating film are excellent. In addition, when the glass transition temperature of the polyester polyol resin is less than the above range, elasticity is increased to decrease the hardness of the paint, and the dryness is inferior to deteriorate the appearance characteristics. Appearance properties are deteriorated and the elasticity of the coating film is lowered, which may cause problems in adhesion and chipping resistance.

In addition, the polyester polyol resin may have a viscosity at 25° C. of 1,000 to 2,500 cps, or 1,070 to 2,270 cps. When the viscosity of the polyester polyol resin is within the above range, the viscosity of the composition is appropriate, so that workability and appearance characteristics are excellent. In addition, when the viscosity of the polyester polyol resin is less than the above range, the viscosity of the composition is too low and the adhesion and chipping resistance of the coating film are reduced due to non-formation of the prepared coating film, and when it exceeds the above range, the workability of the composition Due to this lack, there may be a problem in that the appearance characteristics of the prepared coating film are insufficient.

The polyester polyol resin may have a solid content (NV) of 50 to 80% by weight, or 60 to 80% by weight, based on the total weight of the resin. When the solid content of the polyester polyol resin is less than the above range, a problem occurs in that curing reactivity is lowered due to a decrease in the solid content of the composition. may occur.

In addition, the polyester polyol resin may be included in the composition in an amount of 10 to 40 parts by weight, or 20 to 30 parts by weight based on 5 to 30 parts by weight of the polyester-modified acrylic microgel resin. When the content of the polyester polyol resin is less than the above range, the crosslinking density is lowered, and mechanical properties and appearance are deteriorated. can

Polyester Modified Acrylic Microgel Resin

The polyester-modified acrylic microgel resin serves to improve the appearance characteristics and mechanical properties of the coating film prepared from the composition containing the same.

The polyester-modified acrylic microgel resin may be directly synthesized according to a known method, or a commercially available product may be used. In this case, the polyester-modified acrylic microgel resin may be prepared by, for example, polymerizing an acrylic composition including an ethylenically unsaturated monomer and a polyester-modified acrylic monomer. As another example, the acrylic composition may include 55 to 85 parts by weight or 60 to 75 parts by weight of the ethylenically unsaturated monomer and 15 to 45 parts by weight or 25 to 40 parts by weight of the polyester-modified acrylic monomer. When the content of the ethylenically unsaturated monomer in the acrylic composition is within the above range, the problem of insufficient appearance improvement effect or insufficient weather resistance and compatibility is prevented, and when the content of the polyester-modified acrylic monomer is within the above range, the acrylic resin and It is possible to prevent the problem of insufficient compatibility of

The ethylenically unsaturated monomer may be, for example, an alkyl (meth) acrylate having 1 to 4 carbon atoms substituted or unsubstituted with a hydroxyl group, and specifically, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) It may include at least one selected from the group consisting of acrylate, butyl (meth) acrylate, methyl (meth) acrylate, and 1,6-hexanediol di (meth) acrylate.

The polyester-modified acrylic monomer may be, for example, an acrylic resin whose ends are modified with polyester. As another example, as the polyester-modified acrylic monomer, a conventional microgel emulsion containing an acrylic resin may be used. Specifically, the polyester-modified acrylic monomer has a weight average molecular weight (Mw) of 5,000 to 50,000 g/mol, or 10,000 to 45,000 g/mol, and a glass transition temperature (Tg) of 1 to 20 °C, or 1 to 10 °C can be

In addition, the acrylic composition may further include a styrenic monomer. The styrenic monomer may be, for example, a styrene-based monomer unsubstituted or substituted with an alkyl group having 1 to 4 carbon atoms, and specifically, styrene and α-methylstyrene may be mentioned.

The polyester-modified acrylic microgel resin may have a hydroxyl value (OHV) of 10 to 100 mgKOH/g, or 20 to 90 mgKOH/g. When the hydroxyl value of the polyester-modified acrylic microgel resin is less than the above range, the crosslinking density is lowered and the appearance of the prepared coating film is deteriorated. , there may be a problem that the composition lacks water resistance and weather resistance.

In addition, the polyester-modified acrylic microgel resin may have an acid value (AV) of 1 to 10 mgKOH/g, or 2 to 9 mgKOH/g. When the acid value of the polyester-modified acrylic microgel resin is less than the above range, the curing reaction rate is lowered and the appearance of the prepared coating film is deteriorated. There may be problems with lowering.

The polyester-modified acrylic microgel resin may have a glass transition temperature (Tg) of 30 to 70 °C, or 40 to 60 °C. When the glass transition temperature of the polyester-modified acrylic microgel resin is less than the above range, the drying rate of the paint is delayed and there is a problem that the appearance is deteriorated. This lowering problem may occur.

In addition, the polyester-modified acrylic microgel resin may have a viscosity at 25° C. of 1 to 50 cps, or 10 to 30 cps. When the viscosity of the polyester-modified acrylic microgel resin is within the above range, there is an effect of improving the workability of the composition at the time of manufacturing the paint, thereby improving the appearance characteristics. In addition, when the viscosity of the polyester-modified acrylic microgel resin is less than the above range, the viscosity of the composition is too low and the adhesion and chipping resistance of the coating film are reduced due to non-formation of the coating film. , the workability of the composition may be poor, and thus there may be a problem in that the appearance characteristics of the prepared coating film are insufficient.

The polyester-modified acrylic microgel resin may be a microgel emulsion having a solid content (NV) of 20 to 50% by weight, or 30 to 50% by weight, based on the total weight of the resin. When the solid content of the polyester-modified acrylic microgel resin is less than the above range, it is difficult to manufacture the microgel, and thus the productivity of the paint is lowered. There may be problems with lack of sex.

In addition, the polyester-modified acrylic microgel resin may be a microgel emulsion having an average particle diameter of 50 to 500 nm, or 100 to 300 nm. When the average particle diameter of the polyester-modified acrylic microgel resin is less than the above range, a problem occurs in that mechanical properties are lowered as the resin particle size becomes smaller, and when it exceeds the above range, the appearance is deteriorated as the particle size increases Problems can arise.

The polyester-modified acrylic microgel resin may be included in the composition in an amount of 5 to 30 parts by weight, or 10 to 20 parts by weight based on 10 to 40 parts by weight of the polyester polyol resin. When the content of the polyester-modified acrylic microgel resin is within the above range, the gloss and appearance characteristics of the coating film are excellent. In addition, when the content of the polyester-modified acrylic microgel resin is less than the above range, the drying property is lowered and the paint appearance and workability are deteriorated. A problem in which chipping resistance is lowered may occur.

alkyd resin

The alkyd resin serves to improve the appearance characteristics and mechanical properties of the prepared coating film.

The alkyd resin may be directly synthesized according to a known method, or a commercially available product may be used. For example, the alkyd resin may be prepared by reacting a polyhydric alcohol, a basic acid, and a fatty acid. At this time, the alkyd resin may be prepared by reacting 10 to 40 parts by weight or 20 to 35 parts by weight of a polyhydric alcohol, 15 to 45 parts by weight or 25 to 35 parts by weight of a basic acid, and 3 to 25 parts by weight or 5 to 20 parts by weight of a fatty acid. It may be manufactured.

The polyhydric alcohol is, for example, neopentyl glycol, trimethylolpropane, ethylene glycol, propylene glycol, trimethylolethane, cyclohexanedimethanol, 2-butyl-2-ethyl-1,3-propanediol, 1,4- hexanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, triethylolpropane, glycerin, pentaerythritol, 3-methylpentanediol, and mixtures thereof.

The basic acid is, for example, adipic acid, phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, succinic anhydride, isophthalic acid, azelaic acid, maleic anhydride, trimellitic anhydride, terephthalic acid, fumaric acid, and mixtures thereof.

The fatty acids include, for example, fatty acids of vegetable oils such as coconut, ricinus, tung, olive, soybean, cottonseed, saflower, and dihydrate carbon (DCO); synthetic fatty acids such as pork milk, tallow, train, and deoiled fatty acid (tofa);

The alkyd resin may have a hydroxyl value (OHV) of 20 to 150 mgKOH/g, or 60 to 120 mgKOH/g. When the hydroxyl value of the alkyd resin is less than the above range, a problem occurs in that chemical resistance is lowered due to lowering of curability, and when it exceeds the above range, mechanical properties of the coating film prepared by lowering the molecular weight of the resin may be lowered.

In addition, the alkyd resin may have an acid value (AV) of 0.1 to 70 mgKOH/g, or 1 to 20 mgKOH/g. When the acid value of the alkyd resin is less than the above range, the appearance characteristics of the resin are deteriorated, and when it exceeds the above range, the water resistance of the prepared coating film may be reduced.

The alkyd resin may have a number average molecular weight (Mn) of 1,000 to 10,000 g/mol, or 1,000 to 5,000 g/mol. When the number average molecular weight of the alkyd resin is less than the above range, a problem occurs in that the mechanical properties of the prepared coating film are lowered, and when the number average molecular weight of the alkyd resin is higher than the above range, a problem in that the appearance characteristics of the prepared coating film are deteriorated may occur.

In addition, the alkyd resin may have a glass transition temperature (Tg) of -50 to 30 °C, or -10 to 10 °C. When the glass transition temperature of the alkyd resin is less than the above range, the drying rate is delayed and the appearance characteristics of the coating film are deteriorated.

The alkyd resin may have a viscosity at 25° C. of 500 to 5,500 cps, or 1,000 to 5,000 cps. When the viscosity of the alkyd resin is less than the above range, a problem occurs in that the mechanical properties of the prepared coating film are lowered, and when it exceeds the above range, a problem in that the appearance of the coating film is deteriorated may occur.

In addition, the alkyd resin may be included in the composition in an amount of 1 to 15 parts by weight, or 2 to 10 parts by weight based on 10 to 40 parts by weight of the polyester polyol resin. When the content of the alkyd resin is less than the above range, the reactivity of the composition is lowered and the appearance characteristics of the coating film are deteriorated. A problem of deterioration of weather resistance may occur.

melamine resin

The melamine resin acts as a curing agent for curing the composition by reacting with the components in the composition including the same.

The melamine resin is not particularly limited as long as it is a curing agent commonly used in paints, and for example, hexamethylolmelamine, hexamethoxymethylmelamine, hexabutoxymethylmelamine, and the like may be mentioned.

In addition, the melamine resin may have a weight average molecular weight (Mw) of 500 to 3,000 g/mol, or 700 to 2,800 g/mol. When the weight average molecular weight of the melamine resin is within the above range, there is an effect of improving the adhesion and hardness of the prepared coating film by improving the crosslinking density. In addition, when the weight average molecular weight of the melamine resin is less than the above range, a problem occurs that the chemical resistance of the prepared coating film is lowered, and when it exceeds the above range, a problem that the appearance characteristics of the coating film is deteriorated may occur.

The melamine resin may have a solid content (NV) of 40 to 70% by weight, or 50 to 60% by weight, based on the total weight of the resin. When the solid content of the melamine resin is within the above range, there is an effect of improving low-temperature curability. In addition, when the solid content of the melamine resin is less than the above range, the workability of the composition is lowered and the solid content is lowered.

In addition, commercial products of the melamine resin include, for example, CYMEL-325, CYMEL-303, CYMEL-1161 and CYMEL-1168 by CYTEC, and LUWIPAL 012 and LUWIPAL 072 by BASF.

The melamine resin may be included in the composition in an amount of 5 to 30 parts by weight, or 10 to 20 parts by weight based on 10 to 40 parts by weight of the polyester polyol resin. When the content of the melamine resin is within the above range, there is an effect of improving the adhesion, water resistance and hardness of the prepared coating film by improving the crosslinking density. In addition, when the content of the melamine resin is less than the above range, the curability of the composition is lowered, and a problem occurs in that the mechanical properties and chemical resistance of the prepared coating film are lowered. As a result, there may be problems of reduced adhesion and reduced chipping resistance.

The composition may further include at least one selected from the group consisting of organic solvents, colorants and additives.

organic solvent

The oil-based paint composition for an automobile intermediate may further include an organic solvent. In this case, the organic solvent serves to improve the workability of the composition by adjusting the viscosity of the composition.

The organic solvent includes, for example, aromatic hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone and ethyl propyl ketone; ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, propylene glycol methyl ether acetate (PMA), 1-methoxy-2-propyl acetate, and ethyl ethoxypropionate; and alcohol solvents such as 2-ethylhexanol, isobutanol, n-butanol, propanol and 1-methoxy-2-propanol.

In addition, the organic solvent may be appropriately selected and used according to the characteristics or volatilization rate of the resin contained in the composition. For example, as a commercial item of the said aromatic hydrocarbon type solvent, Cocosol #100, Cocosol #150, etc. are mentioned.

The oil-based paint composition for the middle of an automobile may contain 5 to 50 parts by weight, or 15 to 35 parts by weight of the organic solvent based on 10 to 40 parts by weight of the polyester polyol resin. When the content of the organic solvent in the composition is within the above range, there is an effect of improving the painting workability. When the organic solvent content in the composition is less than the above range, the workability of the composition is insufficient due to the high solid content in the composition. Problems can arise.

tonic

The oil-based paint composition for an automobile intermediate may further include a colorant. In this case, the toner serves to impart color to the prepared coating film.

The colorant is not particularly limited as long as it is a pigment typically used in a paint composition, and, for example, inorganic pigments and organic pigments may be used. As another example, the pigment may include a metal oxide such as titanium dioxide, carbon black, zinc oxide, ultramarine blue, or red iron oxide; sulfides of lithopone, lead, cadmium, iron, cobalt, aluminum and their hydrochloride or lactate; azo pigments; and copper phthalocyanine pigments.

The oil-based paint composition for the middle of an automobile may contain 10 to 30 parts by weight, or 15 to 25 parts by weight of a colorant based on 10 to 40 parts by weight of the polyester polyol resin. When the content of the colorant in the coating composition is less than the above range, a problem of insufficient hiding power of the prepared film occurs.

additive

The oil-based paint composition for automotive intermediate use may further include at least one additive selected from the group consisting of a curing catalyst, a surface conditioner, a light stabilizer, a weather resistance improver, an appearance control agent, an antifoaming agent, a leveling agent, and a dispersing agent.

The additive may be included in the composition in an amount of 0.1 to 10 parts by weight, or 0.5 to 5 parts by weight based on 10 to 40 parts by weight of the polyester polyol resin.

The oil-based paint composition for automotive intermediate use has a viscosity of 10 to 60 seconds, or 15 to 50 seconds, based on Ford Cup No. 4 at 25° C., and a solid content of 30 to 70% by weight based on the total weight of the composition, or 40 to 60% by weight.

As described above, the oil-based paint composition for an automobile intermediate according to the present invention has excellent appearance characteristics, adhesion, repainting properties, chipping resistance, etc. In addition, the composition can be applied to the coating system of 3C1B, thereby lowering the manufacturing cost, the economical efficiency is high.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example]

Synthesis Example 1. Preparation of polyester polyol resin-1

249 parts by weight of neopentyl glycol, 92 parts by weight of trimethylolpropane, and 411 parts by weight of hexahydrophthalic anhydride were put into a four-neck flask equipped with a thermometer, a stirring device, a condenser, a filling column, and a separation tube, and the temperature was raised to 180° C. under a nitrogen atmosphere. and held for 1 hour. After that, the temperature was raised to 230 ° C. over 3 hours to remove the condensed water, 23 parts by weight of xylene was added and refluxed, cooled to 130 ° C., and diluted by adding 274 parts by weight of butyl acetate to prepare a polyester polyol resin-1. .

The prepared polyester polyol resin-1 had a hydroxyl value (OHV) of 120 mgKOH/g, an acid value (AV) of 10 mgKOH/g, a solid content (NV) of 70% by weight, and a viscosity of 2,050 cps at 25 ° C. , the number average molecular weight (Mn) was 1,800 g/mol, and the glass transition temperature (Tg) was 5 °C.

Synthesis Example 2. Preparation of polyester polyol resin-2

255 parts by weight of neopentyl glycol, 94 parts by weight of trimethylolpropane, 298 parts by weight of hexahydrophthalic anhydride, and 117 parts by weight of adipic acid were used as monomers, and 19 parts by weight of xylene and 280 parts by weight of butyl acetate were used as organic solvents. A polyester polyol resin-2 was prepared in the same manner as in Synthesis Example 1 except that.

The prepared polyester polyol resin-2 has a hydroxyl value (OHV) of 130 mgKOH/g, an acid value (AV) of 10 mgKOH/g, a solid content (NV) of 68 wt%, and a viscosity at 25°C of 1,090 cps, , the number average molecular weight (Mn) was 1,800 g/mol, and the glass transition temperature (Tg) was 12 °C.

Synthesis Example 3. Preparation of polyester polyol resin-3

241 parts by weight of neopentyl glycol, 89 parts by weight of trimethylolpropane, and 387 parts by weight of hexahydrophthalic anhydride were put into a four-neck flask equipped with a thermometer, a stirring device, a condenser, a filling column and a separation tube, and heated to 180° C. under a nitrogen atmosphere. The temperature was raised and maintained for 1 hour. After that, the temperature was raised to 230° C. over 3 hours to remove the condensed water, and 22 parts by weight of xylene was added and refluxed, cooled to 170° C., and 31 parts by weight of trimellitic anhydride was added and maintained for 30 minutes. . Thereafter, it was cooled to 130° C. and diluted with 280 parts by weight of butyl acetate to prepare a polyester polyol resin-3.

The prepared polyester polyol resin-3 has a hydroxyl value (OHV) of 120 mgKOH/g, an acid value (AV) of 35 mgKOH/g, a solid content (NV) of 70% by weight, and a viscosity at 25°C of 1,680 cps, , the number average molecular weight (Mn) was 1,300 g/mol, and the glass transition temperature (Tg) was -10 °C.

Synthesis Example 4. Preparation of polyester polyol resin-4

Synthesis Example 1, except that 240 parts by weight of neopentyl glycol, 88 parts by weight of trimethylolpropane, and 421 parts by weight of hexahydrophthalic anhydride were used as monomers, and 22 parts by weight of xylene and 280 parts by weight of butyl acetate were used as organic solvents Polyester polyol resin-4 was prepared in the same manner.

The prepared polyester polyol resin-4 has a hydroxyl value (OHV) of 78 mgKOH/g, an acid value (AV) of 11 mgKOH/g, a solid content (NV) of 72 wt%, and a viscosity at 25 °C of 2,200 cps, , the number average molecular weight (Mn) was 2,000 g/mol, and the glass transition temperature (Tg) was 5 °C.

Synthesis Example 5. Preparation of polyester polyol resin-5

Synthesis Example 1, except that 256 parts by weight of neopentyl glycol, 94 parts by weight of trimethylolpropane, and 396 parts by weight of hexahydrophthalic anhydride were used as monomers, and 22 parts by weight of xylene and 280 parts by weight of butyl acetate were used as organic solvents Polyester polyol resin-5 was prepared in the same manner.

The prepared polyester polyol resin-5 has a hydroxyl value (OHV) of 150 mgKOH/g, an acid value (AV) of 10 mgKOH/g, a solid content (NV) of 70% by weight, and a viscosity at 25°C of 1,020 cps, , the number average molecular weight (Mn) was 1,500 g/mol, and the glass transition temperature (Tg) was 5 °C.

Synthesis Example 6. Preparation of polyester-modified acrylic microgel resin

6-1: Preparation of polyester monomer

400 parts by weight of 12-hydroxystearic acid and 100 parts by weight of toluene were put into a 1,000 ml flask equipped with a stirrer, a thermometer, a dropping tank, a nitrogen inlet tube and a reflux condenser, and the temperature was raised to 70°C. Then, 0.1 parts by weight of methanesulfonic acid was added, and the temperature was raised to 160°C, maintained for 4 hours, and then cooled to 100°C. Thereafter, 50 parts by weight of glycidyl methacrylate was prepared, maintained for 5 hours, and diluted with 300 parts by weight of heptane to prepare a polyester monomer having a solid content of 50% by weight.

6-2: Preparation of polyester-modified acrylic monomer

1666 parts by weight of xylene was put into a four-neck flask equipped with a thermometer and a cooler, and the temperature was raised to 100° C. under a nitrogen atmosphere, and then 400 parts by weight of styrene, 570 parts by weight of methyl methacrylate, 900 parts by weight of butyl acrylate, hydroxyethyl acrylate 500 parts by weight, 130 parts by weight of the polyester monomer prepared in Synthesis Example 6-1, and 30 parts by weight of 2,2'-azobis(2-methylbutylonitrile) were added and reacted, and the solid content was 60.8% by weight and the weight average A polyester-modified acrylic monomer having a molecular weight (Mw) of 13,100 g/mol and a glass transition temperature (Tg) of 2.5°C was prepared.

6-3: Preparation of polyester-modified acrylic microgel resin

600 parts by weight of ionized water and 12.35 parts by weight of an emulsifier were placed in a flask with a condenser, a thermometer and a stirrer attached to four branches, and the temperature was raised to 80° C., 209 parts by weight of ionized water, 2.7 parts by weight of an emulsifier, 123 parts by weight of methyl methacrylate (MMA) , 39 parts by weight of hydroxypropyl methacrylate (HPMA), and 74 parts by weight of 1,6-hexanediol diacrylate (1,6-HDDA) were added dropwise over 3 hours. Then, 90 parts by weight of ionized water and 2 parts by weight of ammonium persulfate (APS) were added dropwise for 3 hours and maintained for 1 hour to prepare a microgel emulsion. At this time, Aerosol@MA-80 was used as the emulsifier.

200 parts by weight of n-butanol (n-BUOH) and 100 parts by weight of KOCOSOL #100 were added to the prepared microgel emulsion to separate the water layer and the resin layer. 110 parts by weight of polyester-modified acrylic monomer and 110 parts by weight of n-BUOH were added to the microgel emulsion, which is the separated resin layer, and water remaining in the emulsion was recovered to prepare an acrylic resin as a microgel resin. The prepared polyester-modified acrylic microgel resin had a solid content of 40% by weight, a viscosity at 25°C of 20cps, a hydroxyl value (OHV) of 61 mgKOH/g, an acid value (AV) of 8 mgKOH/g, and a glass transition The temperature (Tg) was 43°C.

Synthesis Example 7. Preparation of acrylic resin

550 parts by weight of toluene was placed in a four-neck flask, 200 parts by weight of methyl methacrylate, 250 parts by weight of butyl methacrylate, 5 parts by weight of hydroxyethyl acrylate, and 10 parts by weight of acrylic acid were mixed, and 10 parts by weight of the initiator benzoyl peroxide was mixed and refluxed. After uniformly dripping over 3 hours at a temperature and reacting for 2 hours, 1 part by weight of benzoyl peroxide was mixed with 10 parts by weight of toluene and added dropwise, followed by further reaction for 3 hours to terminate the reaction.

The prepared acrylic resin had a solid content of 50.4% by weight, a viscosity of 320cps at 25°C, a weight average molecular weight (Mw) of 25,000g/mol, a hydroxyl value (OHV) of 9.5mgKOH/g, and an acid value (AV) of 12.5 mgKOH/g, and a glass transition temperature (Tg) of 42 °C.

Synthesis Example 8. Preparation of alkyd resin-1

117 parts by weight of neopentyl glycol, 157 parts by weight of trimethylolpropane, 224 parts by weight of phthalic anhydride, 82 parts by weight of adipic acid, and KRATON as fatty acid in a four-neck flask equipped with a thermometer, stirring device, condenser, filling column and separation tube 67 parts by weight of SYLFAT FA2 and 67 parts by weight of coconut oil fatty acid were added, and the temperature was raised to 220° C. over 5 hours under a nitrogen atmosphere and reacted for 1 hour. After that, when the acid value reached 30 mgKOH/g, it was cooled to 160° C., and 21 parts by weight of xylene was added, followed by reflux reaction. After that, when the acid value reached 5 mgKOH/g, the mixture was cooled to room temperature and diluted by adding 320 parts by weight of KOCOSOL-100 to prepare an alkyd resin-1.

The prepared alkyd resin-1 had a hydroxyl value of 98 mgKOH/g, an acid value of 5 mgKOH/g, a solid content of 65% by weight, a viscosity at 25°C of 4,630cps, a number average molecular weight of 2,850 g/mol, and a glass transition temperature of 5 °C.

Synthesis Example 9. Preparation of alkyd resin-2

105 parts by weight of neopentyl glycol, 148 parts by weight of trimethylolpropane, 224 parts by weight of phthalic anhydride, 82 parts by weight of adipic acid, and KRATON as fatty acid in a four-neck flask equipped with a thermometer, stirring device, condenser, filling column and separation tube. 67 parts by weight of SYLFAT FA2 and 67 parts by weight of coconut oil fatty acid were added, and the temperature was raised to 220° C. over 5 hours under a nitrogen atmosphere and reacted for 1 hour. After that, when the acid value reached 30 mgKOH/g, it was cooled to 160° C., and 21 parts by weight of xylene was added, followed by reflux reaction. After that, when the acid value reached 5 mgKOH/g, the mixture was cooled to room temperature and diluted by adding 320 parts by weight of KOCOSOL-100 to prepare alkyd resin-2.

The prepared alkyd resin-2 had a hydroxyl value of 58 mgKOH/g, an acid value of 5 mgKOH/g, a solid content of 65% by weight, a viscosity at 25°C of 4,320cps, a number average molecular weight of 2,820 g/mol, and a glass transition temperature of 5 °C.

Synthesis Example 10. Preparation of alkyd resin-3

117 parts by weight of neopentyl glycol, 157 parts by weight of trimethylolpropane, 232 parts by weight of phthalic anhydride, 89 parts by weight of adipic acid, and KRATON as fatty acids in a four-neck flask equipped with a thermometer, stirring device, condenser, filling column and separator tube 69 parts by weight of SYLFAT FA2 and 69 parts by weight of coconut oil fatty acid were added, and the temperature was raised to 220° C. over 5 hours under a nitrogen atmosphere and reacted for 1 hour. After that, when the acid value reached 30 mgKOH/g, it was cooled to 160° C., and 21 parts by weight of xylene was added, followed by reflux reaction. After that, when the acid value reached 22 mgKOH/g, the mixture was cooled to room temperature and diluted by adding 320 parts by weight of KOCOSOL-100 to prepare alkyd resin-3.

The prepared alkyd resin-3 had a hydroxyl value of 98 mgKOH/g, an acid value of 22 mgKOH/g, a solid content of 65 wt%, a viscosity at 25°C of 4,450 cps, a number average molecular weight of 2,750 g/mol, and a glass transition temperature of 5 °C.

Examples 1 to 14 and Comparative Examples 1 to 10. Preparation of oil-based paint composition

An oil-based paint composition was prepared by stirring and mixing the components at 1,500 rpm for 20 minutes with the composition (parts by weight) as shown in Tables 1 to 3.

(parts by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Polyester Polyol Resin-1 25 30 15 34 - - - - polyester polyol resin-2 - - - - 25 - - - Polyester Polyol Resin-3 - - - - - 25 - - polyester polyol resin-4 - - - - - - 25 - polyester polyol resin-5 - - - - - - - 25 Polyester-modified acrylic microgel resin (Synthesis Example 6) 15 10 15 10 15 15 15 15 Alkyd Resin-1 5 2 10 2 5 5 5 5 melamine resin 15 13 15 10 15 15 15 15 curing catalyst One One One One One One One One tonic 20 20 20 20 20 20 20 20 n-butyl acetate 7 8 8 8 7 7 7 7 Propylene glycol methyl ether acetate 6 8 8 7 6 6 6 6 xylene 3 4 4 4 3 3 3 3 KOKOSOL#100 3 4 4 4 3 3 3 3 total 100 100 100 100 100 100 100 100

(parts by weight) Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Comparative Example 1 Comparative Example 2 Comparative Example 3 Polyester Polyol Resin-1 25 20 30 20 25 25 - 30
30
Polyester-modified acrylic microgel resin (Synthesis Example 6) 7 25 10 10 15 15 30 - 15 Alkyd Resin-1 10 5 One 13 - - 15 10 - Alkyd Resin-2 - - - - 5 - - - - Alkyd Resin-3 - - - - - 5 - - - melamine resin 18 10 19 17 15 15 15 20 15 curing catalyst One One One One One One One One One tonic 20 20 20 20 20 20 20 20 20 n-butyl acetate 7 7 7 7 7 7 7 7 7 Propylene glycol methyl ether acetate 6 6 6 6 6 6 6 6 6 xylene 3 3 3 3 3 3 3 3 3 KOKOSOL#100 3 3 3 3 3 3 3 3 3 total 100 100 100 100 100 100 100 100 100

(parts by weight) Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Polyester Polyol Resin-1 5 42 30 20 30 15 25 Polyester-modified acrylic microgel resin (Synthesis Example 6) 20 10 3 35 10 10 - Acrylic resin (Synthesis Example 7) - - - - - - 15 Alkyd Resin-1 10 2 7 2 0.5 20 5 melamine resin 20 10 15 10 14.5 10 15 curing catalyst One One One One One One One tonic 20 20 20 20 20 20 20 n-butyl acetate 8 5 8 4 8 8 7 Propylene glycol methyl ether acetate 8 5 8 3 8 8 6 xylene 4 2 4 2 4 4 3 KOKOSOL#100 4 3 4 3 4 4 3 total 100 100 100 100 100 100 100

Hereinafter, the manufacturers and product names of each component used in Comparative Examples and Examples are shown in Table 4.

ingredient note melamine resin Manufacturer: CYTEC, product name: CYMEL-325 curing catalyst 2-amino-2-methyl-1-propanol (2-amino-2 methyl-1-propanol) tonic Manufacturer: KCC, Product name: YF4208B

Test Example: Evaluation of the properties of the prepared coating film

On the electrodeposition-coated specimen, the oil-based paint compositions of Examples and Comparative Examples were applied horizontally at a speed of 40 to 50 cm/sec while maintaining a constant distance between the nozzle inlet and the specimen within 30 cm using a handgun to apply an intermediate coating film ( Dry film thickness: 35 µm) was applied. At this time, the nozzle diameter of the handgun was 1.5mm, and the air pressure was kept constant around ^{4.5kgf/cm 2 .}

After that, it is dried at room temperature for 10 minutes, and a base paint (manufacturer: KCC, product name: WT3062, dry film thickness: 15㎛) and clear paint (manufacturer: KCC, product name: TT6830, dry film thickness: 40㎛) is applied, and 140 The final coating film was prepared by drying and curing at ℃ for 25 minutes. Thereafter, the physical properties of the final coating film were measured in the following manner, and the results are shown in Table 5.

(1) Image sharpness

Gloss (LU), sharpness (SH), and orange peel (OP) were measured using Wave Scan DOI (BYK Gardner), an automobile exterior measuring instrument, on the manufactured final coating film, and comprehensive appearance evaluation values using the measured physical properties (CF) was calculated by Equation 1 below.

[Equation 1]

CF = LU X 0.15 + SH X 0.35 + OP X 0.5

At this time, CF was measured and calculated horizontally and vertically.

(2) hardness

The hardness of the final coating film was measured by the pencil hardness method. Specifically, 3B, 2B, B, HB, F, H, 2H, and 3H each of pencils were used to measure the maximum hardness that does not damage the intermediate coat (3B, 2B, B, HB, F, H, 2H). , 3H: inferior ⇔ excellent).

(3) Adhesiveness

100 squares (width 2mm x length 2mm) were drawn on the final coating film with a blade, and the number of squares remaining after removing the squares using a tape was measured to evaluate adhesion.

At this time, the measured adhesion is M-1 (very good) when 100 squares are 100% completely attached, M-2 (excellent) when the remaining squares are 70% or more and less than 100%, and M- when 50% or more and less than 70% 3 (moderate), 30% or more and less than 50% M-4 (bad), and less than 30% M-5 (very bad).

(4) Chipping resistance

After leaving the painted specimen of size 150mmX70mm at -20±3℃ for 3 hours, the chipping resistance was measured using a chipping resistance tester (manufacturer: Grebrometa, model name: SAE J 400).

Specifically, 50 g of chipping stones (diameter: 4 mm) were sprayed at an angle of 45° at a pressure of 4±0.2Kgf/cm ^{2 on the painted specimen.} Thereafter, the specimen was taken out and foreign substances such as the peeled coating film remaining on the coating film were removed with a cellophane adhesive tape.

At this time, when the damaged part of the final coating film was 1 mm or less, it was evaluated as excellent (◎), when it was more than 1 mm and less than 2 mm, it was good (○), when it was more than 2 mm and less than 3 mm, it was normal (Δ), and when it was more than 3 mm, it was evaluated as bad (×).

CF (horizontal) CF (vertical) Hardness adherence chipping resistance Example 1 64 55 HB M-1 ◎ Example 2 64 54 HB M-1 ◎ Example 3 63 52 HB M-1 ◎ Example 4 62 52 HB M-1 ◎ Example 5 62 54 HB M-2 ◎ Example 6 61 51 B M-1 ◎ Example 7 62 52 HB M-1 ○ Example 8 62 51 HB M-2 ○ Example 9 61 52 HB M-1 ◎ Example 10 61 50 HB M-1 ◎ Example 11 60 50 HB M-1 ◎ Example 12 60 51 HB M-1 ◎ Example 13 62 52 HB M-1 ○ Example 14 60 50 HB M-2 ◎ Comparative Example 1 51 42 B M-3 X Comparative Example 2 60 49 2B M-2 ○ Comparative Example 3 58 46 B M-1 X Comparative Example 4 48 44 2B M-3 X Comparative Example 5 56 52 B M-2 △ Comparative Example 6 54 52 B M-2 X Comparative Example 7 50 42 B M-2 X Comparative Example 8 59 46 B M-1 X Comparative Example 9 58 46 B M-2 X Comparative Example 10 59 51 B M-2 △

As shown in Table 5, the coating films prepared from the compositions of Examples 1 to 14 were excellent in appearance characteristics, hardness, adhesion, and chipping resistance.

On the other hand, the coating film prepared from the composition of Comparative Example 1 not including the polyester polyol resin had poor appearance characteristics, adhesion, and chipping resistance.

In addition, the coating film prepared from the composition of Comparative Example 2 not including the polyester-modified acrylic microgel resin had poor hardness.

Furthermore, the coating film prepared from the composition of Comparative Example 3 not including the alkyd resin also had poor chipping resistance.

In addition, Comparative Example 4, in which the content of the polyester polyol resin was small, lacked hardness, adhesion, and chipping resistance, and Comparative Example 5, in which the content of the polyester polyol resin was excessive, was insufficient.

In addition, Comparative Example 6 in which the content of the polyester-modified acrylic microgel resin was small and Comparative Example 7 in which the content of the polyester-modified acrylic microgel resin was excessive had low chipping resistance.

Further, the chipping resistance was also very low in Comparative Example 8, in which the content of the alkyd resin was small, and Comparative Example 9, in which the content of the alkyd resin was excessive.

In addition, Comparative Example 10 including an unmodified acrylic resin had very poor chipping resistance.

Claims (6)

10 to 40 parts by weight of a polyester polyol resin, 5 to 30 parts by weight of a polyester-modified acrylic microgel resin, 1 to 15 parts by weight of an alkyd resin, and 5 to 30 parts by weight of a melamine resin. The method according to claim 1,
The polyester polyol resin has a hydroxyl value of 50 to 200 mgKOH/g, an acid value of 1 to 70 mgKOH/g, a number average molecular weight of 1,000 to 10,000 g/mol, and a glass transition temperature of -30 to 30 ℃, A viscosity at 25°C of 1,000 to 2,500 cps, an oil-based paint composition for automotive intermediates. The method according to claim 1,
The polyester-modified acrylic microgel resin has a hydroxyl value of 10 to 100 mgKOH/g, an acid value of 1 to 10 mgKOH/g, a glass transition temperature of 30 to 70° C., and a viscosity at 25° C. of 1 to 50 cps. Phosphorus, an oil-based paint composition for an automobile intermediate. The method according to claim 1,
The alkyd resin has a hydroxyl value of 20 to 150 mgKOH / g, an acid value of 0.1 to 70 mgKOH / g, a number average molecular weight of 1,000 to 10,000 g / mol, and a glass transition temperature of -50 to 30 ° C. oil-based paint composition. The method according to claim 1,
The alkyd resin is prepared by reacting a polyhydric alcohol, a basic acid and a fatty acid, an oil-based paint composition for an automobile intermediate. The method according to claim 1,
The composition further comprises at least one selected from the group consisting of an organic solvent, a colorant and an additive, an oil-based paint composition for an automobile intermediate.