JPH038392B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a top coating composition, and more specifically to a scratch-resistant and scratch-resistant composition containing an acrylic resin using an ε-caprolactone-modified vinyl monomer as a copolymerization component, an oil-free polyester, an alkyd resin, and a crosslinking agent as binder components. The present invention relates to a top coating composition that forms a coating film with excellent waxability. In recent years, it has been used as a top coat for automobile bodies, etc., such as the finished appearance (texture, smoothness), weather resistance, chemical resistance, mechanical properties, adhesion to undercoat, adhesion when recoating the same paint, etc. In addition to the normally required performance, a high degree of scratch resistance and wax resistance performance is strongly required. Here, scratch resistance refers to the resistance to scratches caused by conventional brushing of hair or the brushes of recent automatic car washes, and wax resistance refers to the resistance to scratches caused by conventional brushing of hair or the brushes of recent automatic car washes. Waxing refers to the property that when applied with wax, the painted surface is less likely to get scratches or become dull, and the rag is less likely to become colored. This waxing resistance is a performance required both for the coating film immediately after painting and for the coating film after being exposed outdoors. Conventionally used alkyd resin-based topcoat paints and acrylic resin-based topcoat paints have poor scratch resistance and waxing resistance, and oil-free polyester-based topcoat paints have
As seen in Publication No. 20068, the waxing resistance is improved to some extent, but the scratch resistance is still insufficient. In addition, each of the above three types of top coat paints has its own advantages and disadvantages in other performance areas, and it is impossible to completely satisfy the performance normally required for top coat paints for automobile bodies, etc. . Therefore, the present applicant previously proposed a thermosetting coating composition that is a mixture of three components: oil-free polyester, acrylic resin, and alkyd resin, and combines the advantages of each resin (Japanese Patent Application Laid-Open No. 57-1989-1).
(See Publication No. 123267). This thermosetting coating composition is
It has excellent performance in terms of finished appearance, weather resistance, chemical resistance, mechanical properties, and adhesion to undercoat and recoat films, and its waxing resistance has also been considerably improved. In terms of scratch resistance, it cannot completely meet the demands of the current market, and improvements are required. Therefore, the present inventors have conducted intensive research in order to obtain a top coat that maintains the performance conventionally required of automotive top coats and has particularly excellent scratch resistance and wax resistance. The results showed that both scratch resistance and waxing resistance are abrasion phenomena of the paint film, and that they can be improved by increasing the abrasion resistance of the paint film by making the paint film more elastic. I did it. However, in order to make the coating film highly elastic, for example, in the case of acrylic resin, it is necessary to use a monomer that lowers the glass transition temperature, and in the case of alkyd resin or oil-free polyester resin, it is necessary to use a monomer that lowers the glass transition temperature. This is possible by using basic acids and soft polyhydric alcohols. However, the coating films obtained using these resins have the disadvantage that they rapidly harden and lose elasticity at low temperatures, and that the coating films block when coated plates are stacked.
There is a problem that a top coat that provides satisfactory performance cannot be obtained. Therefore, the present inventors conducted further research on making the coating film elastic and improving its abrasion resistance without degrading other properties.As a result, we copolymerized an ε-caprolactone-modified vinyl monomer. A specific acrylic resin with a glass transition temperature (Tg) of -50 to 20℃, an acid value of 2 to 50, and a hydroxyl value of 20 to 200 has a remarkable effect on scratch resistance and waxing resistance, and this resin has an acid component. It also has excellent compatibility with a relatively linear specific oil-free polyester containing a saturated alicyclic polybasic acid and an alkyd resin, and as a result, a top coating composition that satisfies all of the above performances using these three types of resins. Furthermore, this top coating composition has excellent flexibility and adhesion with undercoating, so it can be applied to various organic elastomers including polyurethane, which has been increasingly used recently. They discovered this and completed the present invention. Thus, according to the present invention, (A) the following general formula (wherein R: H or CH ₃ , n: 0.5-5) 5-70% by weight of ε-caprolactone-modified vinyl monomer and 95-30% by weight of other radically copolymerizable unsaturated monomers Glass transition temperature (Tg) obtained by copolymerizing with -50 to 20℃, acid value 2 to
50, and an acrylic resin with a hydroxyl value of 20 to 200; (B) at least one of the acid components forming the polyester;
30 mol% is saturated alicyclic polybasic acid, and the horizontal axis is the value obtained by dividing the total number of moles of polybasic acid in the polyester raw material by the total number of moles of polyhydric alcohol (dibasic acid ratio). When the mol% of glycol components with 3 or more carbon atoms in the alcohol is plotted on the vertical axis, (0.8, 60), (0.8, 100), (1.00, 70),
(1.00, 100); (C) an alkyd resin with an oil length of 5 to 50% and a hydroxyl value of 40 to 200; and ( D) A top coating composition containing a crosslinking agent as a binder is provided. The acrylic resin (A) used in the present invention is
general formula (wherein R: H or CH ₃ , n: 0.5-5) 5-70% by weight, preferably 10-50% by weight of an ε-caprolactone-modified vinyl monomer and other radically copolymerizable unsaturated Glass transition temperature (Tg) -50 to 20°C, preferably -40 to 10°C, acid value 2 to 50 obtained by copolymerizing monomer 95 to 30% by weight, preferably 10 to 50% by weight. , preferably 5~
30 and a hydroxyl value of 20 to 200, preferably 50 to 160. The radically polymerizable unsaturated monomer to be copolymerized with the ε-caprolactone modified vinyl monomer includes a radically polymerizable ethylenically unsaturated bond (
There are no particular restrictions as long as the acrylic monomer (a) containing a hydroxyl group and α, β- The ethylenically unsaturated carboxylic acid (d) is a component necessary for the former to provide a hydroxyl value to the acrylic resin (A), and the latter to provide an acid value. Representative examples of such unsaturated monomers are as follows. (a) Hydroxyl group-containing acrylic monomer: for example, _C2-8 hydroxyalkyl ester of acrylic acid or methacrylic acid such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate (b) Acrylic acid or methacrylate Esters of acids: e.g. methyl acrylate, ethyl acrylate,
Propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate,
Acrylics such as octyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, etc. C _1-18 alkyl or cycloalkyl ester of acid or methacrylic acid: acrylic acid or methacrylate such as methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, etc. Alkoxyalkyl ester of acid. Glycidyl acrylate or glycidyl methacrylate and _C2-18 monocarboxylic acid compounds (e.g. acetic acid, propionic acid, oleic acid, stearic acid, lauric acid, p-t
-butylbenzoic acid, etc.), and adducts of Cardiula E-10 and unsaturated acids such as acrylic acid. (c) Vinyl aromatic compounds: e.g. styrene, α
-Methylstyrene, vinyltoluene, p-chlorostyrene, vinylpyridine. (d) α,β-Ethylenically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid. (e) Glycidyl group-containing vinyl monomer: for example, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether. (f) Amides of acrylic or methacrylic acid: for example acrylamide, N-methylolacrylamide, N-butoxymethylacrylamide. (g) Ethylenically unsaturated monomers having alkoxysilane groups: for example γ-methacryloxytrimethoxysilane. (h) Others: Acrylonitrile, methacrylonitrile. These unsaturated monomers are Tg of acrylic resin (A),
Other than satisfying the acid value and hydroxyl value, they are appropriately selected depending on the desired physical properties, and each may be used alone, or two or more types may be combined and copolymerized with the ε-caprolactone modified vinyl monomer. Among these, esters of acrylic acid or methacrylic acid (b) and vinyl aromatic compounds (c) are preferred. The copolymerization of the above-mentioned ε-caprolactone-modified vinyl monomer and radically copolymerizable unsaturated monomer is known from JP-A-57-195714, and is used, for example, to produce an acrylic copolymer. According to a method known per se, for example, solution polymerization method, emulsion polymerization method,
This can be carried out using a suspension polymerization method or the like. Advantageously, the polymerization is carried out according to a solution polymerization method, in which the above two components are generally combined in a suitable solvent in the presence of a polymerization catalyst, usually at a concentration of from about 0 to about 180
The reaction can be carried out at a reaction temperature of about 40 DEG to about 170 DEG C. for about 1 to about 20 hours, preferably about 4 to about 10 hours. As the polymerization catalyst, it is possible to use conventional radical initiators for radical polymerization, such as azo compounds, peroxide compounds, sulfides, sulfines, diazo compounds, nitroso compounds, and redox compounds. Acrylic resin (A) obtained by copolymerizing 5 to 70% by weight of the ε-caprolactone modified vinyl monomer and 95 to 30% by weight of a radically polymerizable unsaturated monomer.
Tg -50~20℃, acid value 2~50 and hydroxyl value 20
~200. In order to obtain the above-described acrylic resin, it is desirable to adjust the amount of monomers in advance so that the glass transition temperature, acid value, and hydroxyl value have the above-mentioned values during its preparation. For the purpose of the present invention, the number average molecular weight of the acrylic resin (A) is preferably in the range of about 1,000 to 30,000. The above glass transition temperature is 1/Tg=ΣWn/Tgn
[Tg: Glass transition temperature (absolute temperature) of copolymer,
Wn: weight fraction of n monomer; Tgn: glass transition temperature (absolute temperature) of n monomer]. The acrylic resin (A) used in the present invention shows unexpectedly excellent scratch resistance and waxing resistance when used in a top coat, but it does not affect the finish of the paint film by itself. Appearance (feeling of flesh,
It has the disadvantages of poor smoothness), poor adhesion to undercoating, and poor adhesion when the same paint is applied over and over again. However, by using the acrylic resin in combination with the specific oil-free polyester (B) and alkyd resin (C) described later, the performance of both acts synergistically to produce a top coat that completely satisfies the above performance. Form. In the above-mentioned acrylic resin (A), if the content of the ε-caprolactone modified monomer is less than 5% by weight, the resulting coating film will have poor elasticity and will not have excellent scratch resistance and waxing resistance. On the other hand, if the amount is more than 70% by weight, the solubility in solvents and the compatibility with oil-free polyester, alkyd resin and crosslinking agent decrease. In addition, acrylic resin (A)
When Tg is lower than -50°C, the coating film becomes sticky; on the other hand, when Tg is higher than 20°C, the coating film loses its elasticity. The acid value is preferably in the range of 2 to 50 in view of the dispersibility of the pigment; outside this range, good pigment dispersibility cannot be obtained, and if it exceeds 50, water resistance deteriorates. Furthermore, the hydroxyl value is
If it is less than 20, the reactivity with the crosslinking agent will decrease, and if it is less than 200
If it exceeds this, water resistance will decrease. The oil-free polyester (B) used in the present invention has an acid component of at least 30 mol%, preferably at least 40 mol% of the total acid component.
contains a saturated alicyclic polybasic acid, and the horizontal axis is the value obtained by dividing the total number of moles of polybasic acid in the polyester raw material by the total number of moles of polyhydric alcohol (dibasic acid ratio),
When the vertical axis is the mol% of the glycol component with 3 or more carbon atoms in the polyhydric alcohol, (0.8, 60),
4 points: (0.8, 100), (1.00, 70), (1.00, 100),
Preferably (0.8, 70), (0.8, 90), (1.00, 80)
,
It is distinctive in that it consists of compositions contained on and within a quadrilateral line surrounded by the four points (1.00, 100). Among the acid components forming the oil-free polyester used in the present invention, examples of saturated alicyclic polybasic acids include hexahydrophthalic acid and its anhydride, methylhexahydrophthalic acid and its anhydride, and hexahydrotrid. Examples include mellitic acid and its anhydride, hexahydro 2-methyltrimellitic acid and its anhydride, and the like. Examples of other polybasic acids include phthalic acid and its anhydride, isophthalic acid and its dimethyl ester, terephthalic acid and its dimethyl ester, trimellitic acid and its anhydride, 2-methyltrimellitic acid and its anhydride, pyromellitic acid Aromatic polybasic acids such as succinic acid and its anhydrides; HOOC (CH ₂ ) such as succinic acid and its anhydrides, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, _etc.
Saturated dibasic acids represented by COOH (n is an integer of 1 to 12); unsaturated polybasic acids such as tetrahydrophthalic anhydride and (anhydrous) maleic acid; and the like. When an unsaturated polybasic acid is used as part of the acid component, the amount used should be adjusted as the unsaturated bonds within the molecule will deteriorate the weather resistance of the coating film in applications where weather resistance is important. For example, it should be kept at 10 mol% or less. If the content of the saturated alicyclic polybasic acid in the acid component is less than 30 mol%, the resulting oil-free polyester will have poor compatibility with acrylic resins and alkyd resins. On the other hand, the polyhydric alcohol component of the oil-free polyester can be comprised of those conventionally used in the formation of polyester. For example, glycol components include dihydric alcohols having 2 carbon atoms such as ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1, 4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, ester diol 204 (product of Union Carbide (USA)), tricyclodecane dimethanol, 1,4-
Examples include dihydric alcohols having 3 or more carbon atoms such as cyclohexanedimethanol, and examples of alcohols having 3 or more hydric acids include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, dipentaerythritol, diglycerin,
Examples include sorbitol. The oil-free polyester is prepared according to a conventional method.
It can be produced by condensation polymerization of a saturated alicyclic polybasic acid together with an aromatic polybasic acid, a saturated dibasic acid, etc. as necessary, and at least one of the alcohols as exemplified above. The molecular weight may be adjusted using, for example, benzoic acid, pt-butylbenzoic acid, benzoic acid methyl ester, etc. as an end-capping agent. The reaction ratio between the polybasic acid component and the alcohol component is determined by the above-mentioned 4.
Adjust so that it is included on and within the quadrilateral line surrounded by the points. Oil-free polyester obtained from a composition outside the above range has poor compatibility with the acrylic resin (A) and alkyd resin (C) used in combination, and cannot be used for the purpose of the present invention. The alkyd resin (C) used in the present invention can be produced by the same method as that of ordinary alkyd resins, and the raw materials used at this time include various materials in addition to those used for producing the oil-free polyester. Natural and synthetic fatty acids and their glycerides are used. Further, as the alcohol component, Cardiura E-10 (product of Shell Petrochemical Co., Ltd.), α-olefin epoxide, etc. can also be used. There are no particular restrictions on the use of fatty acids and their glycerides used for modifying alkyd resins, but since fatty acids and their glycerides with high iodine values tend to deteriorate weather resistance, it is preferable to use fatty acids with high iodine values. A low iodine number is used, for example an iodine value of about 12 or less. The reaction ratio of the raw material components used to produce the above alkyd resin is such that the oil length of the obtained alkyd resin is 15 to 50%, preferably 20 to 45%, and the hydroxyl value is 40 to 200, preferably 50 to 160. is adjusted so that The crosslinking agent (D) used in the present invention is an aminoaldehyde resin and/or a blocked isocyanate as a heat-curing type, and a polyisocyanate as a room-temperature or low-temperature heat-curing type. For the aminoaldehyde resin, melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, etc. are used as amino components, and most aminoaldehyde resins commonly used in paints can be used. Among them, melamine formaldehyde resin is most preferred from the viewpoint of weather resistance. The block type polyisocyanate is tolylene diisocyanate, preferably a non-yellowing type polyisocyanate, such as isophorone diisocyanate,
Hexamethylene diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-
Diisocyanates and their reactants with water or polyhydric alcohols are made into blocked polyisocyanates using conventional blocking agents such as aliphatic or aromatic monoalcohol oximes, lactams, phenols, etc. Takenate B-815N (Takeda Pharmaceutical Co., Ltd. product), Takenate B-840N (Takeda Pharmaceutical Co., Ltd. product), Adduct
B1065 (Veba Chemie (Germany)), ADDITOL
Examples include VXL-80 (manufactured by Hoechst Japan Co., Ltd.). When these blocked polyisocyanates are used, a catalyst that promotes the dissociation of the blocking agent is added if necessary. As the polyisocyanate used for the room temperature or low temperature heating curing type, non-blocked forms of the above-mentioned blocked isocyanates can be used. The acrylic resin used in the present invention exhibits remarkable effects on scratch resistance and waxing resistance, and further exhibits effects on weather resistance, water resistance, and chemical resistance. On the other hand, the oil-free polyester used in the present invention exhibits excellent performance in weather resistance, adhesion to undercoating and repeated coatings of the same paint, and appearance of the coated surface. On the other hand, the alkyd resin used in the present invention has excellent pigment dispersibility and painting workability (does not bleed, sag, and is easy to apply), and has an excellent paint film appearance (no blemishes or sag, and the paint film is smooth). Good gloss and texture) and high gloss. That is, the top coating composition of the present invention mainly exhibits scratch resistance and waxing resistance with the acrylic resin (A), and compensates for the lack of this performance with the oil-free polyester (B) and the alkyd resin (C). The mixing ratio of these three types of resins and the crosslinking agent (D) is determined by considering the role of each of them.
is 10-60% by weight, component (B) is 5-40% by weight, component (C)
is preferably in the range of 5 to 30% by weight, and component (D) is in the range of 10 to 40% by weight. The top coating composition of the present invention may be used with addition of a surface conditioner, a catalyst for accelerating curing, an anti-cissing agent, an ultraviolet absorber, an antioxidant, a quencher, and other additives, if necessary. The thus obtained coating composition of the present invention has excellent scratch resistance, waxing resistance, weather resistance, chemical resistance (acid resistance), ease of painting, appearance of the painted surface, flexibility, water resistance, It has excellent performance in terms of adhesion to undercoats and overcoats, pigment dispersibility, etc., and is particularly suitable as a solid color topcoat for automobile bodies. Furthermore, recently, there has been a demand for high performance that cannot be applied to conventional coatings, such as the application of elastic coatings to bumpers made of various organic elastic materials such as urethane for automobiles, plastic elastic containers, etc. The top coating composition can meet the above requirements due to its high elasticity, towability, adhesion to the undercoat, and the like. In order to paint, for example, an automobile body using the coating composition of the present invention, first, a binder component consisting of an acrylic resin (A), an oil-free polyester (B), an alkyd resin (C), and a crosslinking agent (D) is added. A paint is prepared in the usual way by blending the colored pigments to be used and additives if necessary, and this is diluted with a diluting solvent until the coating viscosity is 20 to 30 at a food cup No. 4 (20℃).
Adjust to seconds. Then, if an undercoat is required, this is applied onto the coating material on which an intermediate coating film has been formed so that the dry film thickness is about 30 to 40 μm. Painting methods include regular air spray, airless spray, and electrostatic painting. The top coating composition contains an aminoaldehyde resin and/or
Alternatively, for the heat-curing type using blocking isocyanate, leave it at room temperature for a few minutes and then heat it at 140-150℃ for 20-40℃.
For room temperature or low temperature curing types using polyisocyanates, heat for 40 minutes if necessary.
After heating at ~80° C. for 20 to 60 minutes and leaving the solution for one day, the top coat film targeted by the present invention is obtained. Hereinafter, the present invention will be explained in more detail with reference to Examples. Parts and percentages in the examples are by weight unless otherwise specified. [] Manufacture of varnish (1) Manufacture of acrylic resin varnish A In a normal acrylic resin varnish manufacturing equipment equipped with a reaction tank, a stirrer, a monomer dropping tank, a heating and cooling device, etc., xylol 40 is placed in the reaction tank.
Add 20 parts of butyl acetate and heat to 112°C. Maintain this temperature (112°C) until the end of the reaction. The monomer mixture described below is then added dropwise to the reaction vessel at a uniform rate over a period of 4 hours. Placcel FM-3 Note- ⁽¹⁾ 40 parts 2-hydroxyethyl acrylate 10 Styrene 10 n-butyl acrylate 39 Acrylic acid 1 2,2'-azobisisobutyronitrile 1.2 Note-(1) Product name: Daicel Chemical Industries Co., Ltd. Manufactured by ε-caprolactone modified vinyl monomer (R: CH ₃ , n=3). One hour after the monomer mixture was added dropwise, 2,2'-azobisisobutyronitrile was added.
Add 0.5 parts at 10 minute intervals in 1/6 portions over 1 hour. Then, the mixture was kept at 112° C. for 1 hour and stirred, and then the reaction was completed and the mixture was cooled.
After cooling, 6.7 parts of xylene was added to obtain acrylic resin varnish A with a solid content of 60%. Tg-35℃, acid value of acrylic resin varnish A
7.8 and the hydroxyl value was 96. (2) Production of acrylic resin varnish B Acrylic varnish B having the following monomer composition was prepared in the same manner as in the case of acrylic resin varnish A (however, the reaction temperature and the amount of 2,2'-azobisisobutyronitrile were different). Manufactured. Placcel FM-3 40 parts 2-hydroxyethyl acrylate 6 Styrene 30 n-butyl acrylate 23 Acrylic acid 1 Acrylic resin varnish B resin content Tg - 11℃,
The acid value was 7.8 and the hydroxyl value was 77. (3) Production of acrylic resin varnish C In the same manner as in the case of acrylic resin varnish A (however, the reaction temperature and the amount of 2,2'-azobisisobutyronitrile are different), acrylic resin varnish C having the following monomer composition is produced. Manufactured. 2-hydroxyethyl acrylate 20 parts Styrene 30 n-butyl acrylate 49 Acrylic acid 1 Tg of acrylic resin varnish C - 23℃, acid value
7.8 and the hydroxyl value was 97. This acrylic resin varnish C is used as a comparative example. (4) Production of oil-free polyester varnish A 72.4 parts of hexahydrophthalic anhydride ( 0.47 mol), phthalic anhydride 28.1 parts (0.19 mol), adipic acid 43.8 parts (0.3 mol), trimethylolpropane 32.8 parts (0.24 mol), neopentyl glycol 58.5 parts (0.56 mol), 1,6-hexanediol 23.6
(0.20 mol) and heat. Once the raw materials have melted and stirring is possible, start stirring.
Raise the reactor temperature to 240°C. however
The temperature is raised uniformly from 160°C to 240°C over 4 hours. The condensed water produced is distilled out of the system through a rectification column. Once the temperature reaches 240°C, keep the temperature constant and continue stirring for 2 hours. After that, xylene is added to the reaction tank and the reaction is continued by switching to the solvent condensation method. When the acid value reaches 7, the reaction is terminated and the mixture is cooled. After cooling, 143 parts of xylene was added to produce an oil-free polyester varnish A having a solid content of 60%. The viscosity of this varnish is Z (Gardner viscosity,
(25°C) The resin acid value was 7.1. (5) Production of oil-free polyester varnish B Oil-free polyester varnish B was produced in the same manner as in the case of oil-free polyester varnish A using the following raw materials. Isophthalic acid 106.2 parts (0.64 mol) Adipic acid 43.8 (0.3 mol) Neopentyl glycol 85.3 (0.82 mol) Trimethylolpropane 24.1 (0.18 mol) The solid content of the obtained oil-free polyester varnish B was 60%, and the viscosity was V ( Gardner viscosity (25°C) and resin acid value were 6.9. This oil-free polyester varnish B is used as a comparative example. (6) Production of alkyd resin varnish A Alkyd resin varnish B was produced in the same manner as in the case of oil-free polyester A using the following raw materials. Phthalic anhydride 132 parts (0.89 mol) Pentaerythritol 58 (0.42 mol) Trimethylolpropane 78 (0.58 mol) Isononanoic acid 142 (0.90 mol) The solid content of alkyd resin varnish A is 60%, and the viscosity is R (Gardner viscosity at 25°C ), the resin acid value is
It was 5.8. Furthermore, the hydroxyl value of the resin component of alkyd resin varnish A was 115, and the oil length was 41%. [] Preparation of coating material (1) Steel sheet material Apply cationic epoxy electrodeposition paint to a dull steel sheet treated with zinc phosphate using the electrodeposition method to a dry film thickness of 20μ and bake at 170℃ for 20 minutes. . Next, polish the painted surface with #400 sandpaper, and then wipe the painted surface with gauze soaked in petroleum benzene to degrease it. After that, an amino alkyd-based automotive intermediate paint was applied to a dry film thickness of 30 μm.
Bake for 30 minutes at ℃. Then, the coated surface was sanded with #400 sandpaper, drained and dried, and the coated surface was wiped with petroleum benzine to provide coating materials for examples of the present invention and for comparison. (2) Flexible material Thickness of reactive injection molded polyurethane resin for automobile bumpers 3
The coating material was made by degreasing a 1.0 mm plate with trichloroethane and applying a volatilized polyurethane resin primer to a dry film thickness of approximately 10 microns. Example 1 A blue top coating paint was prepared using alkyd resin A with the following formulation by dispersion in a pebble ball mill. 60% acrylic resin varnish A 66.7 parts 60% oil-free polyester varnish A 33.3 60% alkyd resin varnish A 16.7 60% Yuban 20SE (Note-2) 50 Heliogen Blue 7040 (Note-3) 10 (Note-2) Mitsui Toatsu Melamine resin (Note 3) manufactured by Kagaku Co., Ltd. Copper phthalocyanine pigment manufactured by BASF (West Germany) Pigment dispersion was performed using alkyd resin varnish A with the addition of an appropriate amount of xylol. 40 ppm of silicone oil KP-322 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the paint as a coating surface conditioner. The obtained paint was coated with Swasol #1500 (Maruzen Sekiyu Co., Ltd.)
petroleum-based solvent)/xylol/butyl acetate/n-
Butanol = 30/20/30/20 mixed solvent with viscosity 26
(Food cup #4/20°C). Air spray the diluted paint onto the previously prepared paint material surface to a dry film thickness of 35μ.
After setting at room temperature for 10 minutes, it was baked in a hot air electric dryer at 140°C for 30 minutes. The test results of the obtained coated plates are shown in Table 2. The pigment dispersion method, the addition of a coating surface conditioner, the method of preparing a test coated plate, etc. are the same as in Example 1 in both the following Examples and Comparative Examples. However, the pigment dispersion in Comparative Example 2 was performed using acrylic resin A. Table 1 shows the paint formulations of Examples 1 and 2 and Comparative Examples 1 to 4.
Shown below. The results of each test are shown in Table 2.

【table】

【table】

[Table] Example 3 60% acrylic resin varnish A 66.7 parts 60% oil-free polyester varnish A 33.3 60% alkyd resin varnish A 16.7 A main liquid of Heliogen Blue 7040 10 was prepared in advance, and then the ratio of hydroxyl groups and isocyanate in the main liquid was determined. Diyuranate 24A-100 (polyisocyanate manufactured by Asahi Kasei Industries, Ltd.) was added so that the (OH/NCO ratio) was 1, and then xylol/butyl acetate/methylisobutyl titone=
Diluted with 40/30/30 solvent for 26 seconds and the above []-
Air spray the flexible material prepared in (2) to a dry film thickness of 35μ, and after setting for 10 minutes,
It was baked for 1 hour at 40°C and then left at 40°C for 24 hours to obtain a test coated plate. As a result of the coating film performance test, 60° specular reflectance, 93,
Taber abrasion resistance, 9mg, pencil hardness, 3B, impact resistance,
In addition to 50, weather resistance, and 82, the various performances listed in Table 2 were all good or ◎. It also passed the test for low-temperature bending resistance (Note 15), which is an important function for flexible materials. (Note-15) Low-temperature bending resistance: After placing the coating liquid in a refrigerator at -30℃ for 4 hours, it was immediately bent 180 degrees with the coated side facing outward between iron rods with a diameter of 10 mm. Observe the paint film at the bent part, and pass if there are no cracks, and reject if cracks are present. Examples 1 to 3 are application examples of the present invention, and are top coatings (particularly Examples 1 and 2 are for top coating of automobile bodies, and 3 is for top coating of flexible materials such as plastic bumpers).
In addition to scratch resistance and wax resistance,
It has shown excellent properties in each test. Comparative Example 1 is an example in which an acrylic resin (A), an alkyd resin (C), and a crosslinking agent (D) were used without using an oil-free polyester (B), and the coating film appearance and interlayer adhesion were poor. Comparative Example 2 is an example in which an acrylic resin (A), an oil-free polyester (B), and a crosslinking agent (D) were used without using an alkyd resin (C), and compared to Examples 1 and 2, the coating was The film appearance and 60° specular reflectance are much worse. Comparative Example 3 is an example using oil-free polyester B, which has poor compatibility and has defects such as poor coating film appearance and glossiness, making it unsuitable as a top coat, so tests for car wash and scratch resistance were omitted. Comparative Example 4 is an example using an acrylic resin that does not use an ε-caprolactone modified vinyl monomer, and is significantly inferior in scratch resistance and waxing resistance. From the above, it is clear that the top coating composition of the present invention has very excellent performance.

Claims (1)

[Claims] 1 (A) The following general formula (wherein R: H or CH ₃ , n: 0.5-5) 5-70% by weight of ε-caprolactone-modified vinyl monomer and 95-30% by weight of other radically copolymerizable unsaturated monomers Glass transition temperature (Tg) obtained by copolymerizing with -50 to 20℃, acid value 2 to 50
and an acrylic resin with a hydroxyl value of 20 to 200; (B) at least one of the acid components forming the polyester;
30 mol% is saturated alicyclic polybasic acid, and the horizontal axis is the value obtained by dividing the total number of moles of polybasic acid in the polyester raw material by the total number of moles of polyhydric alcohol (dibasic acid ratio). When the mol% of glycol components with 3 or more carbon atoms in the alcohol is plotted on the vertical axis, (0.8, 60), (0.8, 100), (1.00, 70),
(1.00, 100); (C) an alkyd resin with an oil length of 5 to 50% and a hydroxyl value of 40 to 200; and ( D) Top coating composition containing a crosslinking agent as a binder.