JPH03222B2 - - Google Patents

Description

[Detailed description of the invention]

In the present invention, a gel coat resin that can be applied by spraying or brushing and has excellent abrasiveness and paintability is used as a surface layer, and then an inorganic fiber reinforcement material and/or an organic fiber reinforcement material is impregnated with a thermosetting resin and hardened to form a backing layer. This article relates to a molding method for reinforced plastic (hereinafter abbreviated as FRP) as a base material. For example, for FRP molds such as those used for leisure boats, molds are taken from the prototype to create the required number of resin molds for mass production, and these are used for production. However, the most commonly used prototype material for FRP is wooden molds.
A master mold is made from this wooden mold, and a large number of FRP production molds are made from the master mold. When making a master mold from a wooden pattern, defects in the original wooden pattern are transferred to the master mold. Traditionally, master molds have been refinished using FRP with a gel coat on the surface, which has poor abrasiveness and also has a lot of residual air bubbles inside, which takes a lot of time to retouch and repair. Furthermore, the production mold is also made of FRP with a gel coat surface layer, and it is necessary to make corrections due to the occurrence of cracks, pinholes, etc. at the stage of production, but it has poor polishability and requires a lot of man-hours. There was a vicious cycle in which air bubbles remained inside during polishing, requiring additional hole-filling work and repair work, which required a large amount of man-hours. In addition, among FRP molding using thermosetting resin, in hand lay-up molding, spray-up molding, cold press molding, and resin injection molding, colored gel coat resin is applied to create a beautiful surface with the desired color. It is common practice to manufacture molded articles having Recently, FRP has come to be used as a vehicle exterior panel material, but it is necessary to color the FRP and steel plate in the same color, improve weather resistance, and paint in multiple colors. It is fundamentally difficult to meet product requirements. Therefore, in order to remove minute defects in the gel coat surface layer, it is necessary to correct the surface before painting the surface. Conventional gel coat resins have poor abrasiveness during polishing and correction, require time to finish, and air bubbles that remain inside appear on the surface during polishing. This requires a subsequent polishing process, which complicates the process. The method for painting the surface of FRP is to form a preliminary shape by impregnating and curing an inorganic fiber reinforcing material and/or an organic fiber reinforcing material with a thermosetting resin, then removing the mold release agent, and adjusting the surface tone with a polysurfacing agent. Is there a method of painting after polishing? It is essential to use air-curing unsaturated polyester resin as the reactive resin for polysurfacing, and it satisfies the various functions and performances required for the surface layer of FRP molded objects. It has been difficult to adopt this method because of its limitations and the large number of steps that inevitably result in high costs. The present inventors have made it easier to repair and paint the surface layer of the above-mentioned reinforced plastic.
As a result of intensive research on FRP molding methods, we ground clay minerals with a plate-like or scale-like crystal grain structure into fine particles with an average particle size of 50μ or less for 100 parts by weight of unsaturated polyester resin containing polymerizable monomers. A gel coat resin composition is prepared by uniformly dispersing 10 to 100 parts by weight of silica and 0.5 to 7 parts by weight of one or more thixotropy imparting agents selected from the group consisting of finely powdered silica, asbestos, and organic bentonite. We have arrived at the FRP molding method of the present invention, which is characterized in that it is coated on a mold and then impregnated and cured with an inorganic fiber reinforcing material and/or an organic fiber reinforcing material with a thermosetting resin to form a backing base material. However, according to the method of the present invention, an unexpected effect is that when stress is applied to the surface layer, cracks are likely to occur because the surface layer does not have a reinforcing material, whereas the surface layer is strong. Moreover, there were no cracks. In addition, according to the method of the present invention, the polishing workability is good when making a master mold from a wooden mold, when creating a product mold from a master mold, and when repairing the mold.Furthermore, there are no air bubbles in the surface layer during polishing, so it is easy to repair. It can be finished immediately without any additional cleaning, resulting in a beautiful surface. Furthermore, when applying paint as the final finishing method,
By adopting this molding method, FRP before painting
The only surface adjustment required is polishing, and there are no defects caused by the underlying surface when baking the paint. The unsaturated polyester resin containing a polymerizable monomer used in carrying out the present invention refers to a resin obtained by dissolving an esterified polycondensate of a dibasic acid component and a glycol component in a polymerizable monomer. The dibasic acid component mentioned above is, for example, an α,β-unsaturated dibasic acid such as maleic anhydride, maleic acid, itaconic acid, citraconic acid, mesaconic acid, or chlorinated maleic acid, and if necessary, phthalic anhydride. acid,
Isophthalic acid, terephthalic acid, monochlorophthalic acid, dichlorophthalic acid, trichlorophthalic acid, hettic acid, tetrachlorophthalic acid, tetrabromo phthalic anhydride, endomethylenetetrahydrophthalic anhydride, adipic acid, succinic acid, sebacic acid, glutaric acid An acid, a saturated dibasic acid such as pimelic acid may be added. On the other hand, glycol components include, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,3-butylene glycol,
2,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, hexylene glycol, octylene glycol, bisphenol A dioxyethyl ether adduct, bisphenol A dioxypropyl ether adduct, hydrogenated bisphenol A, or alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide. Polyhydric alcohols such as trimethylolpropane and glycerin can also be used in combination if necessary. The acid value of the solid unsaturated polyester resin used in the present invention is preferably 20 to 40. Acid value is 40
If it is more than that, there is a tendency to cause problems in water resistance and heat resistance of the cured resin product. Typical polymerizable monomers contained in the unsaturated polyester resin include styrene, α-methylstyrene, vinyltoluene,
Monomers such as chlorstyrene, (meth)acrylic acid and their alkyl esters, acrylonitrile, vinyl acetate, allyl acetate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, acrylamide, diacetone acrylamide, etc. The use of styrene and methyl methacrylate is particularly preferred. The amount of these polymerizable monomers is preferably 20 to 60% by weight based on the total amount with the unsaturated polyester.
In some cases, it is also possible to use polymerizable vinyl ester and polymerizable acrylic urethane together. Further, the unsaturated polyester resin containing the polymerizable monomer may be added with a polymerization inhibitor such as hydroquinone, benzoquinone, toluhydroquinone, t-butylcatechol, or N+N'-dimethylaniline, if necessary. Polymerization accelerators such as cobalt naphthenate and cobalt octenoate can be added. Examples of clay minerals having a plate-like or scale-like crystal grain structure pulverized into fine particles with an average particle size of 50μ or less used in carrying out the present invention include, for example, kaolin minerals, which are generally called clays. Dateskite, nacrite, kaolinite, anorkisite, metahalloysite of the halloysite genus, halloysite; chrysotile of the serpentinite family, commonly called talc, lizardite, six-layer serpentine, antigorite, montmorillonite of the montmorillonite genus, pyrophy light,
Zakorite, nontronite saponite, hectorite; vermiculite minerals such as vermiculite; mica minerals such as illite, sericite, glauconite; and other chlorite minerals; crushed minerals such as attapulgiaite and palygoskite. It is processed into fine particles of 50μ or less, preferably 15μ or less, by separating or classifying. The use of particles with a particle size of 50μ or more results in poor surface smoothness during polishing. The proportion of these clay minerals used is within the range of 10 to 100 parts by weight, preferably 30 to 70 parts by weight, per 100 parts by weight of the unsaturated polyester resin containing the polymerizable monomer. However, if the amount of clay mineral is less than 10 parts by weight, the abrasiveness is not much different from that of ordinary gel coat resin, and if it is more than 100 parts by weight, the viscosity of the compound becomes too high and the air contained in the compound is This is undesirable because it impairs defoaming and causes pinholes and craters in the paint film. Moreover, the clay mineral is not limited to one type, and may be used as a mixture of several types of minerals. As the thixotropy imparting agent used in the present invention, one or more of commonly used fine powder silica, asbestos, and organic bentonite are used in combination. The usage ratio of this thixotropy imparting agent is
100 unsaturated polyesters containing polymerizable monomers
0.5 to 7 parts by weight, preferably 1 part by weight
~5 parts by weight. However, if the amount of the thixotropy imparting agent used is 7 parts by weight or more, air bubbles tend to remain, making spraying and brush coating difficult. On the other hand, if it is less than 0.5 parts by weight, it will tend to drip when applied to vertical areas, making the work difficult. In the method for uniformly dispersing the raw materials prepared as described above, first, a predetermined amount of a thixotropy imparting agent is added to an unsaturated polyester resin containing a polymerizable monomer, and the mixture is stirred using a disper-type stirrer. At this time, a polymerization inhibitor or a polymerization accelerator may be added as necessary. Next, while continuing to stir, a predetermined amount of clay mineral is added little by little and dispersed. At this time, if necessary, a conventional organic or inorganic pigment or a toner color prepared by kneading these pigments with a resin in advance may be added. Normally, the gel coat resin produced as described above can be used immediately, but in particular when smoothness of the surface of the molded product or water resistance is required.
It is necessary to knead through three rolls three to four times. At this time, for color toning, conventional organic or inorganic pigments or toner colors prepared by kneading these pigments with resin in advance can be added. According to the molding method of the present invention, a beautiful surface finish can be easily achieved when making a master mold and a production mold, and when repairing a production mold. In addition, even in the case of FRP molded products that require a paint finish, the only adjustment of the FRP surface before painting is polishing, and there are no defects caused by the base when the paint is baked. Next, the present invention will be explained in detail with reference to Examples and Comparative Examples. Parts and % in Examples and Comparative Examples
are all based on weight. Example 1 0.5 part of 6% cobalt naphthenate was added to 100 parts of Estar G13 (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name of unsaturated polyester resin), 40 parts of Pyrolite was added as a clay mineral crushed to an average particle size of 15μ or less, and shaken. 1.2 parts of Aerosil 200 (trade name, Nippon Aerosil Co., Ltd.) as a modifying agent is added to the resin while stirring and dispersed uniformly. Next, gel coat resin A was produced by passing it through a three-roll roll twice. Next, add 0.8 parts of 55% methyl ethyl ketone peroxide to 100 parts of gel coat resin A, mix uniformly, pour between 35 cm x 35 cm glass plates with 5 mm thick Teflon spacers on three sides, and leave at room temperature for 10 hours. After curing at 80°C for 2 hours, the glass plate was removed to produce a casting plate with a thickness of 5 mm. Cut out three discs with a diameter of 120 mm from this casting board.
The amount of wear was measured in accordance with JIS K7204 "Plastic wear test method using wear wheels". The results are shown in Table 1. Furthermore, 0.8 parts of 55% methyl ethyl ketone peroxide was added to 100 parts of the above A and mixed uniformly.
Spray to a thickness of 0.5 m/m on a glass plate coated with a mold release agent to gel, then cure at 50°C for 30 minutes to obtain unsaturated polyester resin Ester R235A-1 for curing at room temperature.
(Product name of Mitsui Toatsu Chemical Co., Ltd.) Add 0.8 parts of 55% methyl ethyl ketone peroxide to 100 parts, layer 3ply of #450 mat, gelatinize at 80℃ for 3 hours, then 100 parts of 55% methyl ethyl ketone peroxide.
After-cure was carried out at ℃ for 1 hour. This FRP with a surface gel coat layer was polished with #400 sandpaper, then with #600 sandpaper, and finally with #800 sandpaper to check the ease of polishing.After that, 30μ of one-component moisture-curing urethane resin was sprayed. . After setting for 10 minutes, it was cured at 80°C for 30 minutes. The surface finish was visually judged and the results are shown in Table 1. Example 2 Gel coat was made in the same manner as in Example 1, except that Estar R280 (unsaturated polyester resin manufactured by Mitsui Toatsu Chemical Co., Ltd.) was used instead of Estar G13 and kaolinite was used instead of pyrofluorite. Resin B
was manufactured and tested in the same manner. Example 3 Gel coat resin C was produced in the same manner as in Example 2 using 50 parts of talc instead of 40 parts of kaolinite, and tested in the same manner. Example 4 5 parts out of 100 parts of Esther G13 were TR9441-Gray (gray toner manufactured by Toyo Ink Mfg. Co., Ltd., trade name)
In addition to changing 20 parts of the 40 parts of pyrofluorite to illite crushed to less than 5μ,
Gel coat resin D was produced in the same manner as in Example 1 and tested in the same manner. Example 5 Gel coat resin E was prepared in the same manner as in Example 1, except that 0.5 part of RG244 asbestos (trade name manufactured by Union Carbide) was used instead of Aerosil 200.
was manufactured. Example 6 Gel coat resin F was produced in the same manner as in Example 1, except that 7.0 parts of Espen (manufactured by Hojun Yoko Co., Ltd.) was used instead of Aerosil 200. Comparative Example 1 Gel coat resin E was produced in the same manner as in Example 1, except that 40 parts of pyrofluorite was replaced with calcium carbonate having an average particle size of 3 μm or less, and tested in the same manner. Comparative Example 2 Add 0.5 parts of 6% cobalt naphthenate to 100 parts of Ester G13 (mentioned above), and add 2.0 parts of Aerosil 200 while stirring the resin component to uniformly disperse the resin.
Next, gel coat resin F was produced by passing it through three rolls twice, and tested in the same manner as in Example 1. Comparative Example 3 Gel coat resin I was produced in the same manner as in Example 1, except that pyrophyllite with an average particle size of 51 μm was used instead of pyrophyllite with an average particle size of 15 μm or less. Comparative Example 4 Gel coat resin J was produced in the same manner as in Example 1 except that 9 parts of pyrofluorite was added. Comparative Example 5 Gel coat resin K was produced in the same manner as in Example 1, except that 101 parts of pyrofluorite was added.

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Claims (1)

[Claims] 1. 10 to 100 parts by weight of clay minerals having a plate-like or scale-like crystal grain structure pulverized into fine particles with an average particle size of 50μ or less per 100 parts by weight of an unsaturated polyester resin containing a polymerizable monomer. A gel coat resin composition in which 0.5 to 7 parts by weight of one or more thixotropic agents selected from the group consisting of finely powdered silica, asbestos, and organic bentonite is uniformly dispersed is applied to a mold, and then inorganic fibers are applied to the mold. A method for molding reinforced plastics, characterized by impregnating and curing a reinforcing material and/or an organic fiber reinforcing material with a thermosetting resin to form a backing base material.