JP3227260B2 - Manufacturing method of molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plated plastic molded article having excellent gloss, smoothness and adhesion.

[0002]

2. Description of the Related Art In recent years, fiber reinforced plastics (hereinafter FR)
Molded products are excellent in rigidity, mechanical strength, moldability, etc., and are lightweight. Therefore, they are used in many fields such as automobile outer panels and parts, housing equipment parts, and electric product parts as materials that can replace metal. It is being used. When a metal appearance is imparted to an FRP molded product, a plating method is usually employed.

[0003]

However, the FRP molded product has surface defects such as burrows, pinholes, and minute cracks. Therefore, even if directly plated, uniform surface gloss, smoothness, and adhesion are obtained. It was difficult to form an excellent plating layer. In view of the above situation, the present inventors have attempted to solve the above-mentioned problems, and to perform a plating process for an ASB molded product, which has been conventionally ordinarily performed, and a uniform surface gloss and smoothness under plating conditions. As a result of intensive studies to develop a method of manufacturing a FRP molded product capable of forming a plating layer having excellent adhesion and the like, the present invention has been achieved.

[0004]

Means for Solving the Problems That is, the present invention provides (i)
The fiber-reinforced plastic material is heated and pressed in a mold, and (ii) (a) a urethane acrylate oligomer and an epoxy acrylate oligomer (9.9 / 90.
1 to 0/100) [weight ratio] containing a vehicle component mainly composed of an oligomer and a polymerizable unsaturated monomer, and (b) a filler mainly composed of calcium carbonate,
In addition, a coating composition containing the oligomer in an amount of 20 to 60% by weight and the calcium carbonate in an amount of 5 to 50% by weight is poured into the mold, and heated and pressed to form a coating on the surface of the molded article. And (iii) removing the obtained coated molded product from the mold, and then plating the surface of the molded product, and a method for producing a molded product.

Hereinafter, the present invention will be described in detail. As the FRP material used in the present invention, a sheet molding compound (SMC), a bulk molding compound (BMC) and the like can be used. Specifically, a fiber reinforced plastic material such as glass fiber, carbon fiber, and mineral fiber having a matrix of a thermosetting resin such as an unsaturated polyester resin, a vinyl ester resin, a phenol resin, and an epoxy resin is typical. No. The coating composition used in the present invention comprises an epoxy acrylate oligomer or an oligomer composed of the oligomer and a urethane acrylate oligomer, a vehicle component (A) containing polymerizable unsaturated monomers as main components, and a filler containing calcium carbonate as main components ( B) and a polymerization initiator as essential components, and if necessary, a resin for modification, a release agent and other various additives are blended.

[0006] The urethane acrylate oligomer is
For example, (a) an organic diisocyanate, (b) an organic diol and (c) a hydroxyl group-containing (meth) acrylate,
A typical example is a reaction product having a molecular weight of about 300 to 3000 and containing substantially no unreacted isocyanate groups. That is, the components (a), (b) and (c) are mixed and reacted together; the components (a) and (b) are reacted to form a urethane isocyanate intermediate containing an isocyanate group, Then, the intermediate is reacted with the component (c); the components (a) and (c) are reacted to form a urethane (meth) acrylate intermediate containing an isocyanate group, and then the intermediate is reacted with the (b) And the like). (a) The component includes alicyclic isocyanates such as isophorone diisocyanate, methylcyclohexane diisocyanate, and hydrogenated xylylene diisocyanate;
Aromatic isocyanates such as tolylene diisocyanate and xylylene diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate and trimethylene hexane diisocyanate. Examples of the component (b) include alkylene diols such as ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; and polyester diols, which are esterification products of dicarboxylic acids or their anhydrides with excess alkylene diols. (c) As components, 2-hydroxyethyl (meth) acrylate,
2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2
-Hydroxypropyl (meth) acrylate and the like.

[0007] The epoxy acrylate oligomer,
It is produced by reacting a polyepoxide with a stoichiometric equivalent of acrylic acid or methacrylic acid as described in U.S. Pat. Nos. 3,301,743 and 3,337,075. The polyepoxide has two or more epoxy groups, and preferably has a molecular weight of about 300 to 3,000.
A conventionally known polyepoxide can be used as the polyepoxide, specifically, a bisphenol-type polyepoxide obtained by reacting epichlorohydrin with bisphenol A, bisphenol F, bisphenol C, bisphenol S, or the like; by reacting epichlorohydrin with a novolak resin Novolak-type polyepoxide obtained;
Typical examples include cycloaliphatic polyepoxides obtained by epoxidizing the reaction product of butadiene and crotonaldehyde with peracetic acid, and mixtures thereof, but are not limited thereto.

[0008] The polymerizable unsaturated monomer has a function as a viscosity modifier of the coating composition, and radically polymerizes with the polymerizable unsaturated group in the oligomer to form a uniform cured film. Mix. As the polymerizable unsaturated monomer, specifically, styrene, α-methylstyrene,
Divinylbenzene, vinyltoluene; (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate; ethylene glycol;
Representative examples include di- or tri (meth) acrylates of diethylene glycol and trimethylolpropane; functional group-containing monomers such as (meth) acrylic acid, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, and glycidyl (meth) acrylate. Are listed.

The vehicle component (a) comprises the epoxy acrylate oligomer described above or an oligomer comprising the oligomer and a urethane acrylate oligomer, and a polymerizable unsaturated monomer. The mixing ratio of the oligomer composed of the urethane acrylate oligomer and the epoxy acrylate oligomer is (9.9 / 90.1
0/100) [weight ratio] is preferred. If the amount of the urethane acrylate oligomer is excessively added, the coating is deteriorated by an etchant in a plating step described below, and the gloss and smoothness of the plated surface are deteriorated. The oligomer is suitably incorporated in the coating composition in an amount of 20 to 60% by weight in order to exhibit the original coating properties such as the adhesion between the molded product base and the plating layer.
The ratio between the oligomer and the polymerizable unsaturated monomer is
(30/70 to 90/10) [weight ratio] is appropriate,
And the total amount of both is 30 to 70% by weight in the coating composition.
It is appropriate to mix them.

[0010] The filler disperses the shrinkage stress caused by the hardening of the film, improves the adhesion to the base of the molded article, and further fills the above-mentioned burrows and the like existing on the surface of the base of the molded article to make it smooth.
It is blended for the purpose of improving the surface appearance. In particular, in the present invention, a part or all of the filler needs to be made of calcium carbonate so that the film is easily etched by the etching solution. Calcium carbonate is suitably incorporated in the coating composition in an amount of 5 to 50% by weight. As other fillers, it is possible to use color pigments and extenders commonly used for plastics and paints, but the average particle size of the filler is to improve the gloss and smoothness of the plated surface. 10 μm or less is preferred. Other fillers include, specifically, coloring pigments such as titanium oxide in a white system; benzidine yellow, titanium yellow, and hanza yellow in a yellow system; molybdate orange, graphite, and benzidine orange in an orange system; and quinacridone and maroon in a red system. Green type: chrome green, chrome oxide green; blue type: ultramarine, cobalt blue, ultramarine; black type: mica treated with powdered pigments such as carbon black and iron oxide, or flaked iron oxide, nickel, titanium oxide, etc. And the like are typical examples. Typical examples of the extender include talc, barium sulfate, aluminum hydroxide, and clay.

The polymerization initiator generates free radicals and is used to polymerize the vehicle component. As the polymerization initiator, tertiary butyl perbenzoate, tertiary butyl peroctoate, methyl ethyl ketone peroxide, tertiary benzyl perbenzoate, dicumyl peroxide, cumyl hydroperoxide, diacetyl peroxide, caprylyl peroxide,
Tertiary butyl hydroperoxide is a typical example. The amount is suitably about 0.1 to 5% by weight based on the vehicle component. The modifying resin to be blended as required, the dispersibility of the pigment,
It is used to improve fluidity in the mold, storage stability, and the like, or to improve flexibility, adhesion, etching property, and the like of the obtained film. As the modifying resin, those which dissolve or stably disperse in the polymerizable unsaturated monomer are desirable, and saturated polyester, polystyrene, polyvinyl acetate, polyvinyl acetate-acryl copolymer, polyvinyl chloride, polyvinyl chloride- Thermoplastic or thermosetting polymers such as vinyl acetate copolymer, polyvinyl chloride-acrylic copolymer, polyacrylate, polystyrene-butadiene copolymer, polyester, butyral resin, melamine resin, rosin, and cellulose are typical. And the amount can be up to about 30% by weight in the coating composition.

The release agent is added for the purpose of smoothly releasing the cured film from the mold. The types of the release agent include stearates such as zinc, aluminum, magnesium and calcium, lecithin and alkyl. Phosphate and the like are mentioned as typical examples, and the amount thereof is suitably 0.05 to 2% by weight in the coating composition.
Further, various additives such as a curing accelerator, a dispersant, an anti-settling agent, a flow aid, and a polymerization inhibitor can be arbitrarily added as the additives. The coating composition used in the present invention comprises the components described above. Next, a method for producing a molded article of the present invention will be described. As the molding method of the present invention, an injection molding method, a compression molding method, a transfer molding method and the like can be used.
273921 and JP-B-55-9291.

That is, one mold is the other mold (hereinafter, the former is referred to as “lower mold” and the latter is referred to as “upper mold” for convenience).
The FRP material, that is, SMC or BMC is put between the molds that form the cavity space having the shape of the target molded product by fitting into the mold, and heated and pressed in the mold, and the FRP material is heated. And a thermosetting reaction to form a desired shape. The molding heating temperature is arbitrarily determined depending on the molding time, the type of the FRP material, and the like. Usually, 130 to 200 ° C. is appropriate. Is desirably maintained at this temperature until is obtained. The molding pressure is arbitrarily determined depending on the heating temperature, the type of the FRP material, and the like, but is usually 50 to 250 kgf.
/ Cm ² is appropriate.

The molding time may be until the FRP material is completely completed by the thermosetting reaction. However, when the coating composition described below is injected, it is sufficient that the FRP material is cured to such a strength that the molded shape is not damaged. About 20 to 120 seconds is appropriate. Then, the upper mold is separated from the surface of the molded article, and after giving a gap larger than a desired cured film thickness to be described later but insufficient to release the fitting of the mold, or after fitting the mold. While maintaining the molding pressure or 10 to 40 kgf /
After reducing the pressure to about ² cm ² , the desired film thickness, preferably 1
An amount of the coating composition sufficient to obtain a cured film of 0 to 500 μm is press-fitted (injection injected) between the upper mold and the surface of the molded article.
Then, while maintaining the heating temperature substantially at the above-mentioned temperature, the coating composition uniformly covers the surface of the molded article and is about 20-
The pressure is (re) pressed to 140 kgf / cm ² , and usually maintained for about 30 to 180 seconds until a cured film is formed. After the cured film is formed on the surface of the molded product in this manner, the mold is opened, and the obtained coated molded product is taken out of the mold.

Next, a plating layer is formed on the surface of the coated molded article by a known plating method. The following method is suitable as the plating method. That is, as a first step, the surface of the coated molded article is treated in a chemical plating process. In the chemical plating step, first, impurities on the surface are removed by an alkali degreasing method, washed with water, and then degreased with a surfactant-containing solution to improve wettability. Then, etching treatment is performed with an etching solution composed of a mixed solution of chromic acid / sulfuric acid or the like to form anchor-shaped micropores on the surface of the film. Next, chromic acid is removed by washing with water, pickling, and washing. Next, after catalyst treatment, water washing treatment, accelerator treatment, and water washing treatment, nickel was precipitated on the surface in an aqueous solution of nickel chloride / sodium hypophosphite,
Conductivity is imparted, and finally, water washing is performed. As a second step, it is processed in an electroplating process. In the electroplating process, first, after pickling, a strike plating process is performed to improve conductivity, and then a mirror surface gloss is obtained by a copper plating process. Next, a semi-bright nickel plating process and a bright nickel plating process improve the corrosion resistance and the throwing power of chrome plating in a later process. Next, the corrosion resistance is improved by seal nickel plating, and finally, the plated layer is formed by chromium plating.

[0016]

According to the method of the present invention, in the method of plating an FRP molded product, a film made of a specific coating composition is formed in advance on the surface of the FRP molded product, so that the FRP molded product base and the plating layer are The interlayer adhesion is improved, and the resulting plated layer has a characteristic that it has a uniform surface gloss and a smooth surface. Hereinafter, the present invention will be described in more detail with reference to Examples. In the examples, “parts” and “%” are shown on a weight basis. <Preparation of Coating Compositions A to F> The components shown in Table 1 (excluding the polymerization initiator) were kneaded and dispersed, and a polymerization initiator was added immediately before use to prepare coating compositions A to F.

[0017]

TABLE 1 TABLE 1 ──────────────────────────────────── coating composition A B C D E F────────────────────────────────────Bi-urethane acrylate oligomers Note 1) 23--2 28 Epoxy acrylate (Note 2) 28 28 25 35 282 Styrene 25 26 25 30 25 25 ───────────────────────────── {Filled calcium carbonate 23 21 18 15-23 filled titanium oxide 10 10 5 8 20 10 agent talc 10 10 20 10 23 23} ─────────────────── Saturated polyester resin − − 5 − − Zinc stearate 0.5 0.5 0.5. 0.5 0.5 0.5 Hardening accelerator 0.1 0.1 0.1 0.1 0.1 0.1 Tertiary butyl perbenzoate 1.4 1.4 1.4 1.4 1. 41.4４

Note 1) 1 mol of hexamethylene diisocyanate, 1 mol of hydroxyethyl acrylate and 0.5 mol
Reaction product with mol of polypropylene glycol (average molecular weight: 1000) Note 2) Bisphenol A type polyepoxide-diacrylate (average molecular weight: 1100) Examples 1-4 and Comparative Examples 1-3 described in JP-A-61-273921. A molded article having a coating was produced under the following conditions according to a molding apparatus and a molding method. Using a 300 mm long, 150 mm wide chromium-plated flat test die, the die temperature was 150 ° C,
The lower mold was set to 145 ° C. First, 250 g of an SMC material which is an unsaturated polyester-based thermosetting glass fiber reinforced plastic (glass fiber content: 28%) is set on a lower mold, and molded under a molding pressure of 80 kgf / cm ² and a molding time of 60 seconds. did. Next, after reducing the molding pressure to 30 kgf / cm ² , 10 g of each coating composition was injected between the upper part and the molded product,
The molding pressure was again increased to 60 kgf / cm ² and maintained for 90 seconds, then the mold was opened and the coated molded product was taken out. The obtained coated molded product was plated by a chemical plating process and an electroplating process shown in Tables 2 and 3.

[0019]

[Table 2] Table 2 Chemical plating process ───────────────────────────────── No. Item Treatment solution, treatment Conditions １ 1 Degreasing Alkaline degreasing 40 ° C, 4 minutes ─────── ────────────────────────── 2 Rinse ────────────────────── ─────────── 3 Degreasing surfactant 40 ℃, 4 minutes ───────────────────────────── ４4 Etching Chromic acid / sulfuric acid mixed solution 65 ℃, 15 minutes ５5 Washing with water ６ 6 Pickling hydrochloric acid / hydrazine 40 ℃, 4 minutes ───────────────────────────────── 7 Rinse ────────── ─────────────────────── 8 Catalyst palladium chloride / stannous chloride / hydrochloric acid solution 23 ℃, 4 minutes ───────── ９ 9 Washing 水───────── 10 Accelerator sulfuric acid / hydrazine ───────────────────────────────── 11 Rinse ───────────────────────────────── 12 Chemical nickel Nickel chloride / aqueous sodium hypophosphite solution ───── ──────────────────────────── 13 Rinse ── ──────────────────────────────

[0020]

[Table 3] Table 3 Electroplating process ───────────────────────────────── No. Item Treatment solution, treatment Conditions １ 1 Pickling ───────────── ──────────────────── 2 Strike Potassium oxalate, Potassium pyrophosphate plating pH9, 30 ℃ ──────────────── ────────────────── 3 Copper plating Copper sulfate / sulfuric acid 23 ℃ ─────────────────────── ───────────4 Semi-bright nickel Nickel sulfate, nickel chloride, sulfur boric acid plating pH 4.0 53 ° C ───────────────────── ５ 5 Bright nickel nickel sulfate Nickel chloride, boric acid plating pH4.0 55 ℃ ───────────────────────────────────6 Seal Nickel Sulfuric acid Nickel, nickel chloride, powder, ru plating Boric acid pH 4.0 53 ° C ５３ 7 Chromium plating Chromic acid / sulfuric acid aqueous solution 40 ℃ ─────────────────────────────────── Plating treatment obtained Each test was performed on the adhered area ratio, gloss, smoothness, and adhesion of the plating layer in the molded article obtained, and the results are shown in Table 4.

[0021]

[Table 4] Example 4 Comparative Example 1 2 3 4 1 2 ─────────────────────────────────── Coating composition No. ABCDEF Plating area Ratio (%) 100 100 100 100 90 100 Gloss * 3) 8 7 8 8 5 2 Smoothness * 4) (μm) 0.12 0.14 0.08 0.08 0.20 0.25 Adhesion * 5) (g / cm) 750 680 700 650 240 200 ───────────────────────────────────

Note 3) A fluorescent lamp was projected on the test piece from a position of 2 m, and the way of reflection was ranked by the five measurers in the following 10 ranks, and the average value was used as the gloss value. Rank: 10 The shape of the fluorescent lamp is clearly reflected, like the mirror surface. Rank: 8 The shape of the fluorescent lamp appears slightly cloudy. Rank: 5 The shape of the fluorescent lamp is clouded. Rank: 3 The shape of the fluorescent light appears quite cloudy. Rank: 1 The shape of the fluorescent lamp is not reflected at all. In addition, the rank without description is a rank between the above-mentioned ranks. Note 4) Center line average roughness (Ra) based on JIS B 0601 Note 5) Make a 10 mm width scratch on the plating layer with a cutter knife,
The end was sandwiched between chucks of a tensile tester, a tensile test was performed at an angle of 90 °, and the adhesion was measured.
No. 4 has a plating layer formed on the entire surface,
Both smoothness and adhesion were good. On the other hand, in Comparative Example 1 in which calcium carbonate was not blended, a portion where a plating layer was not formed occurred, and in Comparative Example 2 in which the urethane acrylate oligomer was excessive, gloss, smoothness, and adhesion were poor.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Fujii 878 Mitsubuchi Nishinomon, Komaki City, Aichi Prefecture Dainippon Paint Co., Ltd. Komaki Plant (72) Inventor Kenji Yonemochi Mitsubuchi Nishinomon, Komaki City, Aichi Prefecture 878 Dainippon Paint Co., Ltd. Komaki Factory (72) Inventor Mitsutoshi Mitsutoshi Mitsuchi Nishinomon, Komaki City, Aichi Prefecture 878 Dainippon Paint Co., Ltd. Komaki Factory (56) References JP-A-5-104554 (JP, A JP-A-4-252233 (JP, A) JP-A-5-59589 (JP, A) JP-A-4-228592 (JP, A) JP-A-58-125762 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B29C 43/18-43/20 B29C 43/32-43/34 C08J 7/04 C08F 299/02-299/06

Claims (1)

(57) [Claims] (1) A fiber-reinforced plastic material is heated and pressed in a mold, and (ii) (A) (9.9 / 90.1-0) of a urethane acrylate oligomer and an epoxy acrylate oligomer. / 1
00) [weight ratio], a vehicle component mainly composed of an oligomer and a polymerizable unsaturated monomer, and (b) a filler mainly composed of calcium carbonate. A coating composition containing 60% by weight of the calcium carbonate and 5 to 50% by weight of the calcium carbonate is injected into the mold, and heated and pressed to form a film on the surface of the molded article. After removing the coated molded product from the mold,
A method for producing a molded product, comprising plating the surface of the molded product.