JPH0246068B2 - METARITSUKUTORYOSOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to coatings suitable for metallic coatings, and in particular to metallic coating compositions suitable for basecoats using metallic coating finishes. Furthermore, the present invention relates to a metallic coating composition that can provide a coating film with improved metal unevenness and metallic feel compared to conventional metallic coatings, without impairing the storage stability of the coating material. Prior Art Conventionally, metallic coatings, in which electrodeposited primers, intermediate paints, metallic base coats (hereinafter referred to as base coats), metallic top clear coats (hereinafter referred to as top clears), etc. are laminated on metal materials, have come to account for the majority of automotive paint systems. In this laminated metallic coating film, the electrodeposited primer has the main purpose of preventing corrosion of the metal material, and the intermediate coat has the effect of smoothing the top coat and as a base to obtain a glossy coating film, and the electrodeposited primer has a different function. It has the effect of keeping the primer and topcoat in close contact for a long time, and the topcoat can be finished with a meridian color containing ordinary inorganic and/or organic pigments, or colored with a base coat containing metallic powder such as aluminum or bronze.
The purpose is to give the material long-term weather resistance,
Additionally, metallic base coats are usually coated with a top clearer which protects the base coat from metal powder alignment and waxing after the coating is completed. For such metallic coatings, in order to shorten the process and save energy, the base coat and top clear coat are coated wet-on-wet and then cured by heating, using the so-called 2c/1b (two-coat, one-bake) method. It is painted. While this 2c/1b method has many advantages, it also has the following problems due to the final aesthetic finishing process. In other words, the conventional 2c/1b method that has been used for a long time is a combination of a base coat made of acrylic resin and a top clear, and when the top clear of the same type is coated again, the top clear is coated with a solvent or the resin is coated with a top clear. There was a problem in that the metal in the base coat moved due to their compatibility with each other, causing so-called metal unevenness. In order to overcome the above-mentioned deficiencies, studies have been conducted on the use of cellulose acetate butyrate (hereinafter referred to as CAB) in combination, and on CAB-modified acrylic resins that are reacted during the production of acrylic resins, and have been put into practical use. The metallic feel was not sufficient. Based on the above circumstances, in order to further improve the metallic feel of metallic coatings, polyester resin and
A base coat containing CAB mixed during paint manufacturing and a top clear coat made of acrylic resin are being considered. According to such a coating system, metal unevenness can be almost prevented, but polyester resin and
Due to the poor compatibility of CAB, there are problems such as gelation or layer separation during storage as a paint, and poor workability, making it difficult to achieve the intended purpose. It's not working. OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a metallic coating composition that can improve the metal unevenness and metallic feel of a metallic coating without impairing the storage stability and workability of the coating. In this specification, "metal unevenness" refers to metal powder in raw paint that changes its orientation due to convection, etc., and metal powder that is fixed during the drying process and is applied wet-on-wet to the top coat. This means that the above-mentioned orientation is disturbed when In addition, "metallic feel" refers to the extent to which the scale-like metal powder in the base coat maintains parallelism and continuity with respect to the spread of the paint film. It is best to have continuity in which metal powder is always present in the cross section.
Depending on various conditions, the flaky metal powder may not be parallel but may be partially upright or inclined, or the metal powder may lack continuity, resulting in a decreased metallic feel. Structure of the Invention The metallic coating composition according to the present invention comprises a modified polyester resin containing an oxirane group obtained by reacting a polyester resin with an acid anhydride and then an epoxy compound, and a modified polyester resin containing cellulose acetate butyrate with an acid anhydride. The main component of the vehicle is a resin obtained by reacting a carboxyl group-containing modified cellulose acetate butyrate obtained by reacting an anhydride. Other metallic coating compositions according to the invention include:
The vehicle contains as a main component a resin obtained by reacting an isocyanate group-containing modified polyester resin obtained by reacting a polyester resin with an isocyanate compound and cellulose acetate butyrate. Detailed Description of Structure and Effects of the Invention As described above, the first metallic coating composition according to the present invention is an oxirane obtained by reacting a polyester resin with an acid anhydride and then reacting with an epoxy compound. A group-containing modified polyester resin and a carboxyl group-containing modified cellulose acetate butyrate obtained by reacting cellulose acetate butyrate with an acid anhydride, preferably 95/5 to 30/70,
Further, the vehicle preferably contains a resin obtained by reaction at a weight ratio of 90/10 to 50/50 as a main component. The second metallic coating composition according to the present invention contains an isocyanate group-containing modified polyester resin obtained by reacting a polyester resin with an isocyanate compound, and cellulose acetate butyrate, preferably in a ratio of 95/5 to 30/70. ,
More preferably, the resin obtained by the reaction is contained as a main component of the vehicle in a weight ratio of 90/10 to 50/50. Polyester resins used as starting materials for the modified polyester resin used in formulating the metallic coating composition of the present invention include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, Commonly used as alcohol components for conventional polyesters, such as dihydric alcohols such as pentyl glycol, trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane, and tetrahydric or higher alcohols such as pentaerythritol and dipentaerythritol. polyhydric alcohols, including phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, trimellitic anhydride, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid,
Polymers commonly used as acid components for conventional polyesters, such as tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 6-methylhexahydrophthalic anhydride, hexahydro trimellitic anhydride, and esters thereof (e.g., methyl ester). It can be any polyester resin obtained by a condensation reaction with a basic acid or an acid-forming derivative thereof, and the polyester resin used in the present invention may further optionally contain coconut oil, soybean oil, safflower oil, Natural oils and fats such as tall oil and fatty acids, Cardiura E (Ciel Chemical Co., Ltd.) α-alkyl (9 to 11 carbon atoms) monocarboxylic acid 2,3-
Oils or fatty acids commonly used as components for conventional alkyd resins can be added, such as synthetic resin acids such as epoxypropanoyl esters. From the viewpoint of weather resistance, it is preferable that the oil length is 10% or less. According to the present invention, the polyester resin described above is modified by reaction with an acid anhydride and a subsequent epoxy compound to obtain a modified polyester resin containing oxirane groups or a modified polyester resin containing isocyanate groups by reaction with an isocyanate compound. The polyester resin is then used as a reactive component of the vehicle-based resin of the metallic coating composition of the present invention. The oxirane group-containing modified polyester resin is prepared by first combining a polyester resin with an acid anhydride such as phthalic anhydride, succinic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, trimellitic anhydride, or pyromellitic anhydride. react, then this reaction product and Epicoat
It is manufactured by reacting epoxy compounds such as 828, Epicote 1001, Epicote 1004 (manufactured by Ciel Chemical), ERL4202, and ERL4206 (manufactured by Union Carbide). For example, the reaction between the polyester resin and the acid anhydride is performed under conditions of 60 to 150°C for about 1
It is carried out by a time ring-opening addition reaction. Further, the reaction between the acid anhydride-modified polyester resin and the epoxy compound is carried out using, for example, a tertiary amine such as benzyldimethylamine or tributylamine as a catalyst. The isocyanate group-containing modified polyester resin is produced by reacting a polyester resin with a diisocyanate compound at 50 to 80°C using a tin compound such as dibutyltin dilaurate or a tertiary amine such as tributylamine until the isocyanate equivalent is doubled. Manufactured by Cellulose acetate butyrate (hereinafter referred to as "CAB") used in the formulation of the metallic coating composition of the present invention includes ASTM-D-817,
It is preferable that the viscosity according to D-1343 method is 0.1 to 80 seconds, the acetyl group content is 2 to 13% (ASTM-D-817), and the butyryl group content is 30 to 50 mol% (ASTM-D-817), A typical example of such a CAB is Eastman Chemical Products Co.
CAB−551−0.01, CAB−551−0.2, CAB−531
-1, CAB-500-1, CAB-500-5, CAB-
381−0.1, CAB−381−0.5, CAB−381−2,
Examples include CAB-381-20. According to the present invention, the CAB described above is modified with an acid anhydride and then reacted with the modified polyester resin containing an oxirane group, or directly with the modified polyester resin containing an isocyanate group, and the resulting resin is used as a metallic resin according to the present invention. Used as the main vehicle component of coating compositions. The reaction of CAB with an acid anhydride (e.g., phthalic anhydride, succinic anhydride, maleic anhydride) can be carried out, for example, by a ring-opening addition reaction at a temperature of 60 to 150°C for about 1 hour. The reaction between the acid anhydride-modified CAB and the oxirane group-containing modified polyester resin, which is blended as the main vehicle component of the metallic coating composition according to the invention, may be carried out by stirring at a temperature of, for example, 100 to 150°C. On the other hand, the reaction between CAB and the modified polyester resin containing isocyanate groups can be carried out by reacting the isocyanate groups at a temperature of, for example, 70 to 100°C. Property modification CAB
The resin obtained by the reaction between CAB and a modified polyester resin containing an oxirane group or by the reaction between CAB and a modified polyester resin containing an isocyanate group is blended in the metallic paint in an amount of 30 to 90% by weight, preferably 50 to 80% by weight. As the crosslinking agent used in the metallic coating composition of the present invention, components commonly used as crosslinking agents for conventional thermosetting coatings, such as melamine, benzoguanamine, urea, and isocyanate-based curing agents, can be used. modified polyester resin/
The crosslinking agent ratio is generally used in a solid content ratio of 95/5 to 50/50. In addition to the above-mentioned vehicle component, the metallic coating composition of the present invention contains components generally included in conventional metallic coating compositions, such as metal pigments such as aluminum, bronze powder, mica powder, and titanium-coated mica, carbon black, Coloring pigments such as general inorganic pigments such as titanium dioxide, general organic pigments such as phthalocyanine blue, phthalocyanine green, Shinka Sharetsu, and flavan yellow, additives such as surface conditioners and anti-settling agents can be blended. can. Solvent components that can be used in the present invention include Solbetsuso 100, Solbetsuso 150 (manufactured by Etsuso), toluene,
Aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as hexane, heptane, cyclohexane,
Solvents used in general paints, such as alcohols such as ethanol, butanol, and isobutanol, and esters such as ethyl acetate, butyl acetate, amyl acetate, and cellosolve acetate, can be selected in consideration of solubility and boiling point. However, during resin production, it is necessary to avoid using solvents having hydroxyl groups in the reaction step using acid anhydrides or isocyanate compounds. When applying the metallic paint composition according to the present invention, it is diluted with thinner to a predetermined viscosity, and
Paint using an air spray gun, electrostatic paint gun, minibell paint gun, etc. After a flash time of 2 to 5 minutes at room temperature, a clear paint is diluted from a transparent liquid containing no pigment and then applied. 5～10
After setting for a minute, bake in an electric oven or gas oven. The coating film thus obtained has excellent metal unevenness and metallic feel. That is, there is no disturbance in the orientation of the metal powder, and the arrangement of the metal powder maintains parallelism and continuity with respect to the spread of the coating film. Furthermore, the composition of the present invention exhibits better storage stability and a smaller degree of viscosity increase than metallic paints in which polyester resin and CAB are blended during paint production. Examples Examples and comparative examples of the present invention will be described below, but it goes without saying that the scope of the present invention is not limited to these examples. Examples 1 to 4 Production of resin D-1 (1) Production of polyester resin A-1 693 g of phthalic anhydride, 299 g of trimethylolpropane, 226 g of neopentyl glycol, and 125 g of Cardiura E-10 (manufactured by Ciel Chemical Co., Ltd.) were added by a conventional method. After reacting at 200°C to 220°C, the mixture was diluted with xylene to obtain a resin solution A-1 with a nonvolatile content of 50%. This resin has a calculated molecular weight
1,600, OH value (solid content equivalent) was 110, and acid value (solid content equivalent) was 10. (2) Modification of resin A-1 Polyester resin A-1 produced above
2508g and 14.8g of phthalic anhydride were heated and mixed at 120℃ for 1 hour, and then the epoxy resin ERL-
14.8 g of 4206 (manufactured by Union Carbide) and 6.4 g of benzylmethylamine were added and reacted at 140°C until the epoxy equivalent was doubled to obtain resin solution B-1. (3) Modification of CAB 20% solution of CAB551-0.2 (Eastman Chemical Products) (CAB/cellosolve acetate/xylol 20/40/40) 695 g
and 14.8 g of phthalic anhydride were kept warm at 120° C. for 1 hour and stirred to carry out a reaction, and a resin solution C-1 was obtained. (4) Reaction of resin solution B-1 and resin solution C-1 2538 g of resin solution B-1 and 1710 g of resin solution C-1
Heated at 140℃, acid value (solid content equivalent)
The reaction was carried out until the weight ratio of polyester resin/CAB reached 8, resulting in a resin solution D-1 with a polyester resin/CAB weight ratio of 90/10.
I got it. Production of Resin D-2 (1) Production of Polyester Resin A-2 831 g of isophthalic acid, 183 g of adipic acid, 194 g of trimethylolpropane, 312 g of neopentyl glycol, and 327 g of 1.6 hexanediol were reacted at 200°C to 220°C using a conventional method. After drying, the solution was diluted with xylene to obtain a resin solution A-2 with a non-volatile content of 50%. This resin has a calculated molecular weight
1,600, OH value (solid content equivalent) was 110, and acid value (solid content equivalent) was 10. (2) Modification of resin A-2 3208 g of fat A-2 produced above and 14.8 g of phthalic anhydride were heated and mixed at 120°C for 1 hour, and then 37.4 g of epoxy resin Epicoat 828 (manufactured by Ciel Chemical) and benzyldimethylamine were mixed. 6.4g
was added and reacted at 140°C until the epoxy equivalent was doubled to obtain resin solution B-2. (3) Modification of CAB 15% solution of CAB381-20 (CAB/cellosolve acetate/xylol 15/42.5/
42.5) 1187 g and 14.8 g of phthalic anhydride, 120
The reaction was carried out by keeping the temperature at °C for 1 hour and stirring to obtain resin solution C-2. (4) Reaction of resin solution B-2 and resin solution C-2 3260g of resin solution B-2 and resin solution C-2
1202 g was heated to 140° C. and the reaction was carried out until the acid value (in terms of solid content) reached 8 to obtain a resin solution D-2 having a polyester resin/CAB ratio of 90/10. Production of Resin D-3 (1) Production of Polyester Resin A-3 831 g of isophthalic acid, 183 g of adipic acid, 209 g of trimethylolpropane, 345 g of neopentyl glycol, and 272 g of 1.6-hexanediol were reacted at 200 to 220°C using a conventional method. After cooling, it was diluted with xylene to obtain a resin solution A-3 with a non-volatile content of 50%. This resin had a calculated molecular weight of 1700, an OH value (in terms of solid content) of 110, and an acid value (in terms of solid content) of 10. (2) Modification of resin A-3 3188 g of polyester resin A-3 and 14.8 g of phthalic anhydride were heated and mixed at 120°C for 1 hour, and then 14.8 g of epoxy resin ERL4206 and 6.4 g of benzyl dimethyl were added at 140°C until the epoxy equivalent was 2. React until doubled in size.Resin solution B-3
I got it. (3) Modification of CAB 3415 g of a 20% solution of CAB551-0.2 and 14.8 g of phthalic anhydride were heated and stirred at 120° C. for 1 hour to carry out a reaction to obtain resin solution C-3. (4) Reaction of resin solution B-3 and resin solution C-3 3209g of resin solution B-3 and resin solution C-3
3,430 g was heated to 140° C. and the reaction was carried out until the acid value (in terms of solid content) reached 8 to obtain a resin solution D-3 having a polyester resin/CAB ratio of 70/30. Production of resin D-4 (1) Modification of resin A-3 3188 g of polyester resin A-3 obtained above
222g of isophorone diisocyanate and 2.0g of dibutyltin dilaurate were added to the mixture at 60°C.
The reaction was carried out until the isocyanate equivalent was doubled, and then a 20% solution of CAB551-0.2 was added.
Add 18,595g of polyester resin and continue the reaction at 100℃ until the isocyanate group disappears.
Resin solution D-4 with CAB of 30/70 was obtained. Manufacture of Paint 1 22 g of Aluminum Base 7130N (manufactured by Toyo Aluminum) was thoroughly loosened with the same amount of xylol to make a uniform paste. Add to this the resin solution D- prepared above.
1 122g and butylated melamine Yuban 20SE-
60 (manufactured by Mitsui Toatsu Chemicals) was added to obtain silver enamel paint. Manufacture of paints 2 to 4 Paints 2 to 4 have the following formulation using the same manufacturing method as paint 1 above.
I got 4.

[Table] Comparative Examples 1 to 4 Polyester resin before reacting with CAB
A paint with the following composition was made from CAB and butylated melamine. The polyester resin/CAB/melamine ratio was the same as in the example.

[Table] Comparative Example 5 Almatex NT-U-23 (manufactured by Mitsui Toatsu Chemical Co., Ltd.)/Yuban as an acrylic base coat paint
I made a paint whose 20 is 8/2. The aluminum concentration was the same as in the example. Creation of test piece 1 Electrodeposit Powertop U-30 (electrodeposition paint made by Nippon Paint) on a light dull steel plate at 300V for 3 minutes (film thickness approximately 15μ) and bake at 180℃ for 25 minutes.
Apply Olga 100 No. 71 intermediate coating gray (intermediate coating paint made by Nippon Paint) (film thickness approximately 25μ) and bake at 140℃ for 30 minutes. After baking, it was water-sanded with 400 paper, and after draining, it was wiped with petroleum benzene to prepare the object to be painted. 2. Dilute the aforementioned silver paint with a thinner consisting of ethyl acetate/toluene/Solbetsuso 150/Cellosolve Acetate (50/20/20/10) in a food cup No. 4 for 14 seconds/20°C, and
Paint in two stages using No. 71 (spray gun made by Iwata Coating Machine) to achieve a dry film thickness of 13 to 15μ. After 3 minutes of flash time, apply Superac 0-28L and clear (acrylic rear manufactured by Nippon Paint) to a dry film thickness of 25-27μ. After setting for 10 minutes, bake in an electric oven at 140℃ for 30 minutes. Evaluation Test The sharpness, metallic feel, and metal unevenness of the dry line coatings of the paints of Examples 1 to 4 and Comparative Examples 1 to 5 produced above were evaluated by the following methods. 1 Sharpness Measured using a sharpness gloss meter (manufactured by Tokyo Kohden). The larger the PGd value, the closer the surface is to a mirror surface. 2 Metallic Feel A test piece (9 cm x 20 cm x 0.8 mm) was viewed directly in front of the naked eye under sunlight and the whiteness of the painted surface was compared. ◎...Excellent 〇...Good ×...Poor At the same time, L measured by a variable angle colorimeter (manufactured by Suga Test Instruments)
We also measured the value (at an acceptance angle of 15 degrees). This indicates that the larger the value, the higher the reflectance of light. 3 Metal unevenness The uniformity of the arrangement of aluminum powder was compared with the naked eye. ◎...Excellent 〇...Good ×...Poor The results obtained are shown in Tables 1 and 2 below. 4 Storage stability The viscosity of metallic paint measured by a viscometer is
Dilute with thinner until 65Ku/20° and heat at 50°C.
After storage for 10 days, the viscosity was measured again.

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【table】

Claims (1)

[Claims] 1. Reacting an acid anhydride with a polyester resin,
Next, an oxirane group-containing modified polyester resin obtained by reacting an epoxy compound with a carboxyl group-containing modified cellulose acetate butyrate obtained by reacting cellulose acetate butyrate with an acid anhydride is reacted. A metallic paint composition comprising the obtained resin as a main component of a vehicle. 2 The ratio by weight of the modified polyester resin and the modified cellulose acetate butyrate is 95/
5-30/70 composition according to claim 1. 3. A metallic coating composition characterized by containing as a main vehicle component a modified polyester resin containing isocyanate groups obtained by reacting a polyester resin with an isocyanate compound and a resin obtained by reacting cellulose acetate butyrate. . 4 The ratio by weight of the modified polyester resin and cellulose acetate butyrate is 95/5 to 30/
70. The composition according to claim 3, wherein the composition is