JP2006297268A - Method of manufacturing plastic automobile component having hairline pattern and chrome plated tone metallic feeling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a plastic automobile component having a hair line pattern, chrome plated tone metallic feeling, high weather resistance and excellent designability. <P>SOLUTION: The plastic automobile component having the hairline pattern and chrome plated tone metallic feeling on the surface is manufactured by applying hairline-processing on the surface of the plastic automobile component, forming a black coating film, applying a metallic coating material containing a base resin component comprising a cellulose acetate butylate resin, an acrylic resin and a cross-linking agent and a luster pigment component on the black coating film to form a metallic coating film having light transparency in a degree of exhibiting the chrome plated tone metallic feeling. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a plastic automobile part having excellent design properties, and more specifically, production of a plastic automobile part having a hairline pattern, a chrome-plated metallic feeling, and having weather resistance and excellent design characteristics. Regarding the method.

Conventionally, in plastic automobile parts used for the interior and exterior of automobiles, a method of imparting a metallic feeling to the surface has been widely used in order to impart aesthetics and the like. As a method of imparting a metallic feeling, the surface of plastic automobile parts
(1) A method of chrome plating,
(2) Method of painting with metallic paint,
(3) A method of coating with a paint using a pulverized product of a deposited metal film,
Etc. are known as typical methods.

  However, in order to carry out the above method (1), it is necessary to impart conductivity to the plastic surface, and thus it is necessary to perform electroless plating or the like to form a conductive film on the surface of the plastic substrate. is there. In addition, it is necessary to immerse the entire base material in a plating bath, which complicates the manufacturing process and has various limitations on equipment.

  In the method (2), paints mainly containing an aluminum paste pigment are applied to express design properties with the aluminum paste pigment (see, for example, Patent Document 1 and Patent Document 2). However, the reflected light of the aluminum paste pigment has problems such as inferior in design compared with the chromium plating process by the method (1).

  In recent years, as a method of the above (3), a method of applying a metallic paint containing a glittering pigment obtained by pulverizing a deposited metal film into a metal piece has been proposed (for example, Patent Document 3, Patent Document 4, Patent Document). 5 and Patent Document 6). However, the bright pigment obtained by pulverizing the deposited metal film to form a metal piece has problems that it is unstable with respect to an acidic substance or an alkaline substance, has poor orientation, and tends to be uneven.

  In addition, plastic automobile parts not only have a chrome-plated metallic feel, but also have hair-like patterns formed on the surface of metal parts such as aluminum and steel for surface decoration of acoustic products, home appliances, etc. That is, design properties such as hairline processing are required.

As a method of giving a metallic feeling to the surface of a plastic member and applying hairline processing,
(A) It was made by rubbing sandpaper on the surface of an injection molding die to form a large number of elongated grooves extending in one direction on the die surface, and injection molding using the die. A method of coating the surface of a resin molded product with a metallic paint or a pearl paint at an appropriate thickness (see Patent Document 7);
(B) Metallic glitter with a glittering paint obtained by grinding a glittering synthetic resin film into a powder or plate shape of 5 to 50 μm square on the metallic coating surface of the undercoat and mixing it with an acrylic paint. After painting, a method of applying hairline processing to the painted surface and then applying clear coating to the surface (see Patent Document 8),
Etc. are known as typical ones.

  However, in the above method (a), for example, a paint containing aluminum powder is applied to express the design, but the reflected light of the aluminum powder is not sufficient in terms of design, and the above (b) ) Has a problem that it is inferior in terms of weather resistance since the method of applying hairline processing to the glitter paint surface is employed.

JP-A-11-10062 Japanese Patent Laid-Open No. 11-19588 JP 2003-113348 A JP 2000-176365 A JP 11-343431 A Japanese Patent Laid-Open No. 11-80620 Japanese Patent Laid-Open No. 10-71677 JP 2002-45785 A

  The present invention has been made against the background of the problems of the prior art as described above, and is a plastic automobile part having a hairline pattern, a chrome-plated metallic feel and excellent weatherability. The object is to provide a method that can be manufactured.

  As a result of intensive studies to achieve the above object, the present inventors have performed hairline processing on the surface of plastic automobile parts, then formed a black coating as an undercoat, and the black coating surface has a specific composition. A metallic coating containing a base resin component and a bright pigment component is applied to form a metallic coating. In this case, a light-transmitting metallic coating is formed to such an extent that the black coating of the undercoat can be seen through. Thus, the inventors have found that a hairline pattern can be formed on the surface of a plastic automobile part, and that a metallic feeling of chrome plating can be imparted and weather resistance can be imparted, and the present invention has been completed.

  That is, in the method of manufacturing a plastic automobile part having a hairline pattern on the surface of the present invention and having a chrome-plated metallic feeling, the surface of the plastic automobile part is subjected to hairline processing, and then a black coating film is formed. A metallic coating containing a base resin component composed of cellulose acetate butyrate resin, acrylic resin and its cross-linking agent and a bright pigment component is formed on the film to form a metallic coating, and the metallic coating is chrome-plated. It is characterized by being light transmissive to such an extent that it exhibits a metallic feeling.

  By the production method of the present invention, it is possible to produce a plastic automobile part having a hairline pattern, a chrome-plated metallic feeling and excellent weatherability.

  The plastic automatic type parts that are the subject of the present invention may be made of any resin as long as the resin has properties such as strength and impact resistance required for automobile parts. For example, AS resin, ABS resin, acrylic resin, etc. Resin, polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin, polymethyl methacrylate resin, polyallyl diglycol carbonate resin and the like.

  In the present invention, it is necessary to perform hairline processing on the surface of plastic automobile parts. This hairline processing is carried out, for example, by forming a hair-like fine groove on the surface by rubbing sandpaper or a metal brush in one direction against a desired surface of a plastic automobile part. The hairline processing is preferably performed on the plastic surface so as to have a depth of about 2 to 3 μm.

  In the present invention, it is necessary to form a black coating film on the surface of plastic automobile parts. This black coating film is formed by applying a black paint, and as the black paint used here, a black paint generally used as a primer for a plastic substrate can be used.

  These primers can be used regardless of organic or inorganic. Examples of organic primers are selected from the group consisting of nylon resin, alkyd resin, epoxy resin, acrylic resin, organically modified silicone resin (for example, acrylic silicone resin), chlorinated rubber resin, urethane resin, phenol resin, polyester resin and melamine resin. The organic primer composition etc. which contain 10 mass% or more of at least 1 sort (s) of organic resin as solid content can be mentioned.

Examples of the inorganic primer include an inorganic primer composition containing 90% by mass or more of an inorganic resin such as a silicone resin as a solid content.
The black primer used in the present invention is generally blended with the resin composition described above in an amount of about 2 to 3 parts by mass per 100 parts by mass of the resin solid content of carbon black or black pigment. It is what.

  In this invention, the dry film thickness of the black coating film formed by black primer coating becomes like this. Preferably it is 10-20 micrometers, More preferably, it is 13-17 micrometers. When the dry film thickness of the black coating film is less than 10 μm, the black coating film has insufficient concealment power, and the plastic base material that is the base tends to show through. Since the metal feeling of the chrome plating tone which is the object of the invention tends to be insufficient, it is not preferable. On the contrary, when the dry film thickness of the black coating film exceeds 20 μm, it tends to become familiar with the metallic coating film formed on the black coating film. In such a case, the chromium plating which is the object of the present invention is provided. This is not preferable because the metallic tone tends to be insufficient.

In the present invention, the metallic paint is applied on the black coating film, but this metallic paint can be applied while the black coating film is not dried or after it is dried.
In the present invention, in order to ensure weather resistance, a metallic paint containing a base resin component comprising a cellulose acetate butyrate resin, an acrylic resin and a crosslinking agent thereof, and a bright pigment component is applied.

  The cellulose acetate butyrate resin used in the present invention includes a cellulose derivative obtained by butyl esterification of a partially acetylated product of cellulose or a modified product thereof, and already known ones can be used without limitation. Specific examples include trade names “CAB381-0.5”, “CAB551-0.2”, “CAB531-1” and the like manufactured by Eastman Chemical Co., Ltd.

  The acrylic resin used in the present invention can be produced from an acrylic monomer. As such acrylic monomers, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, lauryl Acrylate, tridecyl acrylate, stearyl acrylate, cyclohexyl acrylate, benzyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2-phenoxyethyl acrylate, ethyl carbitol acrylate, allyl acrylate Acrylics such as glycidyl acrylate, dimethylaminoethyl acrylate, acrylic acid, sodium acrylate, trimethylolpropane acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol acrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate Mention may be made of acid esters, acrylic acid and acrylate monomers.

  Furthermore, as an acrylic monomer that can be used for the production of acrylic resins, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate Propyl methacrylate, benzyl methacrylate, isopropyl methacrylate, sec-butyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, allyl methacrylate, Tylene glycol methacrylate, triethylene glycol methacrylate, tetramethylol propane methacrylate, 1,3-butylene glycol methacrylate, trimethylol propane methacrylate, 2-ethoxyethyl methacrylate, 2-methoxyethyl methacrylate, dimethylaminoethyl methyl chloride salt methacrylate, methacrylic acid, Mention may be made of methacrylic acid esters such as sodium methacrylate, methacrylic acid and methacrylate monomers.

  In addition to the acrylic monomer components described above, as copolymerization components, vinyl monomers such as acrylamide, acrylonitrile, vinyl acetate, ethylene, propylene, isobutylene, butadiene, isoprene, chloroprene, glycidyl (meth) acrylate, methyl glycidyl (meta ) Epoxy group-containing ethylenically unsaturated monomers such as acrylate, allyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth) acrylate, and carboxyl group-containing ethylenically unsaturated monomers such as crotonic acid, itaconic acid, maleic acid and fumaric acid Hydroxyl-containing ethylenically unsaturated monomers such as hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate can be used.

  Acrylic resin can be produced by synthesizing a high molecular weight resin by a normal solution polymerization method, then removing the solvent by a thin film heating and decompression method, etc., or a resin by a suspension polymerization method. Then, there is a method of producing a solid resin by removing moisture by a spray drying method or the like.

  As a crosslinking agent for the acrylic resin as described above, when the reactive polar group in the acrylic resin is a glycidyl group, a polyfunctional carboxyl group-containing compound such as sebacic acid or dodecanedicarboxylic acid, a polyfunctional acid anhydride, etc. In addition, when the reactive polar group in the acrylic resin is a hydroxyl group or both a hydroxyl group and a carboxyl group, a blocked isocyanate resin, a melamine resin, or the like can be used.

  As blocked isocyanate resins that can be used as crosslinking agents, isocyanate resins such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, and toluene diisocyanate and trimethylolpropane are added and reacted, and polyfunctionalized isocyanate resins. Examples thereof include blocked isocyanate resins obtained by blocking resins, hydrogenated and polyfunctionalized isocyanate resins and the like with caprolactone and oximes.

  When these blocked isocyanate resins are used as a cross-linking agent, a resin that is solid even with a blocked isocyanate resin alone is preferred because of the need to ensure the stability of the solid resin particles, and the resin from isophorone diisocyanate is ε-caprolactone. Blocked blocked isocyanate resins are preferred. However, liquid blocked isocyanate resins can also be used by adjusting the amount of addition, the amount of pigment, etc., or by combining with acrylic resins, polyester resins, etc. having a high glass transition temperature.

  In the present invention, those used in ordinary metallic paints can be used as the bright pigment component, for example, metal powders such as aluminum powder, copper powder, bronze powder, titanium dioxide-coated mica powder, and mica-like iron oxide. A pigment etc. can be mentioned.

  The metallic paint used in the present invention contains, as necessary, a base resin component and a bright pigment component composed of the above components, a coloring pigment, an organic solvent, a coating surface conditioner, a curing catalyst, other It may contain additives such as pigments and pigment dispersants.

  Examples of the color pigment include, for example, titanium dioxide, zinc white, lead white, carbon black, acetylene black, graphite, vermilion, cadmium red, antimony vermilion, bengara, bitumen, ultramarine, cobalt blue, chromium oxide green, guinea green, and chromium. Examples thereof include inorganic pigments such as green, zinc green, and iron oxide, and organic pigments such as azo, phthalocyanine, quinacridone, dioxazine, and isoindolinone.

  Examples of the organic solvent include aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, alcohols, esters, ethers, ketones, and the like. Specifically, toluene, xylene , Methylnaphthalene, naphtha, mineral spirit, cyclohexane, methanol, ethanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, glycol monoethyl ether, glycol monobutyl ether, glycol monomethyl ether acetate, glycol monoethyl ether acetate, methyl ethyl ketone, methyl Examples thereof include isobutyl ketone. These solvents may be used alone or in combination of two or more.

  In the metallic paint used in the present invention, the solid content of acrylic resin as the base resin component and the solid content of cellulose acetate butyrate resin are preferably present in a mass ratio of 100: 45 to 55, More preferably, it is present in an amount of 52. When the acrylic resin and the cellulose acetate butyrate resin are present in a mass ratio outside the above range, the metallic coating film has many irregular reflections, and the metallic luster tends to be dull.

  About the compounding quantity of the crosslinking agent in the metallic paint used by this invention, for example, about the compounding ratio of a hydroxyl-containing acrylic resin and a (block) polyisocyanate compound, the number of hydroxyl groups of a hydroxyl-containing acrylic resin and the (block) polyisocyanate compound. The ratio to the number of isocyanate groups is preferably in the range of 1: 0.6 to 1.5, more preferably 1: 0.8 to 1.2. If the above ratio of the blending ratio is less than 1: 0.6, the weather resistance, stain resistance, water resistance and the like of the coating film tend to be lowered. On the other hand, if the above ratio exceeds 1: 1.5, There is a tendency for the stain resistance, weather resistance, etc. of the film to decrease.

  In the metallic paint used in the present invention, the solid content of the base resin component and the bright pigment component are preferably 100: 25 to 35, more preferably 100: 28 to 32, by mass ratio. When the base resin component and the luster pigment component are present in a mass ratio outside the above range, the metallic coating film has many irregular reflections and tends to be dull in metallic luster, which is not preferable.

  In the present invention, in order to produce a plastic automotive part having an excellent chrome-plated metallic feel on the surface, the metallic coating can be seen through the black coating and light enough to exhibit a chrome-plated metallic feel. It is essential to be permeable. If it is light-impermeable or light transmittance is too low, it will not be possible to see through the black coating on the lower layer, there is no difference from the conventional metallic coating, and the surface of the chrome-plated metal is excellent It is not possible to obtain a plastic automobile part having a feeling. Conversely, when the light transmittance is too high, the influence of the black coating film in the lower layer is so strong that it almost becomes a black coating film and the metallic property tends to be insufficient, which is not preferable. In the present invention, the light transmittance of the metallic coating film measured in the wavelength range of 400 to 700 nm is preferably about 20 to 50%, and more preferably about 45 to 50%.

  The light transmittance of the metallic coating film varies depending on the type, size, shape, type of resin, and the like of the bright pigment in the metallic coating film. Specifically, it is preferable to apply the coating so that the dry film thickness of the metallic coating film is 1 to 2 μm, and it is more preferable to apply the coating film so that the dry film thickness is 1.3 to 1.7 μm.

  In the present invention, a clear coating can be formed by further applying a clear coating on the surface of the metallic coating. A thermosetting resin composition comprising a base resin and a cross-linking agent is preferable as a coating film component in the clear paint. As a base resin, it can be used by appropriately selecting from known resins. Specifically, an acrylic resin, a polyester resin having at least one crosslinkable functional group selected from the group consisting of a hydroxyl group, an amino group, a blocked isocyanate group, a carboxyl group, and an epoxy group in one molecule, Urethane resin or the like is particularly suitable.

  Examples of the crosslinking agent include melamine resins that can be crosslinked and cured with the crosslinkable functional groups, block polyisocyanate compounds, carboxyl group-containing compounds, and the like.

  The coating method for the black paint, metallic paint and clear paint can be appropriately selected from known coating methods and is usually carried out by air spray, airless spray, electrostatic coating or the like.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In Examples and Comparative Examples, “parts” and “%” are shown on a mass basis unless otherwise specified.

<Preparation of black paint>
Hitaroid 3901 (trade name, manufactured by Hitachi Chemical Co., Ltd., acrylic resin, NV 50%) 75 parts, Sumijoule N-75 (trade name, manufactured by Sumitomo Bayer Urethane Co., Ltd., HDI burette type polyisocyanate), 3 parts carbon black, A dispersion consisting of 0.1 part of a dispersant lecithin (Ajinomoto Oil Co., Ltd. trade name, fatty acid oil) and 21.9 parts of a solvent (a mixture of butyl acetate, xylene, methoxybutyl acetate and methoxypropyl acetate) was mixed with a disper. A black paint was prepared.

<Preparation of metallic paint>
ACRIDIC A-804 (Dainippon Ink Chemical Co., Ltd., trade name, acrylic resin, NV 50%) 10 parts, CAB381-05 (Eastman Chemicals trade name, cellulose acetate butyrate resin, NV 10%) 25 parts, Sumidur N-75 (trade name, manufactured by Sumitomo Bayer Urethane Co., Ltd., HDI burette type polyisocyanate), 5 parts of aluminum paste 7160NS (trade name, manufactured by Toyo Aluminum Co., Ltd .; NV70%), 3 parts of dispersant Desperon 4200-10 Product name made by Kasei Corporation; fatty acid amide wax NV10% 1 part and solvent (mixture of butyl acetate, toluene, xylene, methoxybutyl acetate and Solvesso 150) 61 parts are mixed with a disper to prepare a metallic paint did.

<Preparation of clear paint>
75 parts of Acrydic BU-955 (trade name, acrylic resin, NV 60%, manufactured by Dainippon Ink and Chemicals, Inc.), 15 parts of Sumidur N-75 (trade name, manufactured by Sumitomo Bayer Urethane Co., Ltd., HDI burette type polyisocyanate) 2 parts of ultraviolet absorber (Ciba Specialty Chemicals), 1 part of additive BYK-331 (BIC Chemie Japan trade name; polyether-modified polydimethylsiloxane) and solvent (butyl acetate, toluene, xylene, methoxybutyl acetate and Mixture of methyl isobutyl ketone) A mixture of 22 parts was mixed with a disper to prepare a clear paint.

<Example 1>
The above black paint is applied to the surface of the ABS resin plate on which a hairline pattern having a groove depth of 2 to 3 μm is formed with sandpaper of # 500 so as to have a dry film thickness of 15 μm, and then dried and black coated. A film was formed. The metallic paint was applied onto the black coating film so that the dry film thickness was 1.5 μm, and baked. The light transmittance of the metallic coating film measured in the wavelength range of 400 to 700 nm was 45%. The completed coating film had a hairline pattern, the underlying black coating film was seen through, and had a chrome-plated metallic feel.

<Example 2>
The above black paint is applied to the surface of the ABS resin plate on which a hairline pattern having a groove depth of 2 to 3 μm is formed with sandpaper of # 500 so as to have a dry film thickness of 15 μm, and then dried and black coated. A film was formed. The metallic paint was applied onto the black coating film so that the dry film thickness was 1.5 μm, and baked. Next, the above clear coating was applied and baked to a dry film thickness of 25 μm. The completed coating film had a hairline pattern, the underlying black coating film was transparent, and had a deep chrome-plated metallic feel.

<Comparative Example 1>
The above black paint is applied to the surface of the ABS resin plate on which a hairline pattern having a groove depth of 2 to 3 μm is formed with sandpaper of # 500 so as to have a dry film thickness of 15 μm, and then dried and black coated. A film was formed. A metallic paint was applied on the black coating film so as to have a dry film thickness of 5 μm and baked. The completed coating film was a metallic coating film, but the light transmittance measured in the wavelength range of 400 to 700 nm of the metallic coating film was 10%, so the hairline pattern was not visible, and the underlying black coating film was It was not visible at all, and a metallic feeling of chrome plating was not obtained.

<Comparative Example 2>
The above black paint is applied to the surface of the ABS resin plate on which a hairline pattern having a groove depth of 2 to 3 μm is formed with # 500 sandpaper, and dried to give a black coating. A film was formed. The metallic paint was applied onto the black coating film so that the dry film thickness was 1.5 μm, and baked. The finished coating was a metallic coating, but it had a hairline pattern, but the underlying black coating was too thin to allow the ABS resin to show through, and a chrome-plated metallic feel was obtained. There wasn't.

Claims (5)

  A metallic coating containing a base resin component and a bright pigment component comprising a cellulose acetate butyrate resin, an acrylic resin and a cross-linking agent formed on the coating film after a hairline treatment is applied to the surface of a plastic automobile part. A metallic coating film is formed by applying a paint, and the metallic coating film has a hairline pattern on the surface and has a chrome plating texture, characterized by being light-transmitting to the extent that it exhibits a chrome-plated metallic feeling. Of manufacturing plastic automobile parts having a metallic feeling.   In the above metallic paint, the solid content of the base resin component and the bright pigment component are present in an amount of 100: 25 to 35 by mass ratio, and the acrylic resin solid content and the cellulose acetate butyrate resin solid content are Is present in an amount of 100: 45 to 55 in mass ratio.   The method for producing a plastic automobile part according to claim 1 or 2, wherein the light transmittance of the metallic coating film measured in a wavelength range of 400 to 700 nm is 20 to 50%.   4. The plastic automobile according to claim 1, wherein the black coating film has a dry film thickness of 10 to 20 μm, and the metallic coating film has a dry film thickness of 1 to 2 μm. A manufacturing method for parts. The method for producing a plastic automobile part according to any one of claims 1 to 4, wherein a clear coating is further formed on the surface of the metallic coating to form a clear coating.