JPH0376331B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a molding composition for FRP,
More specifically, FRP is suitable for molding FRP products that have excellent surface smoothness and can be coated with a coating film without creating wrinkles or pinholes.
The present invention relates to a molding composition for use. FRP (Fiber Reinforced Plastics) was originally made by filling unsaturated polyester resin with glass fibers.
It was developed as a material with extremely high strength, and has since been applied to other thermosetting resins and even thermoplastic resins. FRP has higher mechanical strength per unit weight than general metal materials, so it is a material that can be used to make products that are lighter and stronger than metals.FRP also has excellent physical properties such as heat resistance, cold resistance, weather resistance, and moldability. It is widely used in various structural materials, automobile parts, exterior materials, etc. Particularly in recent years, in order to improve workability and productivity, reinforcing materials such as glass fibers are pre-impregnated with resin and other fillers and hardening agents, for example, in the form of sheets (SMC,
Molding compounds for FRP in a dry semi-cured state, such as TMC) and block or rod-like (BMC), have been developed and are widely used for molding FRP articles. By the way, since FRP articles have poor surface smoothness, or in order to further improve appearance, weather resistance, abrasion resistance, etc., the surfaces of FRP articles are painted. Such coating is also necessary, for example, in the case of automobile parts, in which the parts are painted in a desired color to match the color scheme of the entire automobile or to be painted integrally with the body of the automobile. However, when conventional solvent-based paints are applied to FRP products, there is a problem that foaming occurs during the baking process, causing so-called wrinkles and pinholes in the paint film, which impairs the performance and appearance of the paint film. The problem is assumed to be that air, other gases, and volatile components are contained within FRP products, and these are released to the outside during the paint baking process. Furthermore, even when a urethane-based primer is applied to an FRP article, the above-mentioned foaming phenomenon during baking is not improved, and baking also occurs when a solvent-based paint is applied after applying pliers to an FRP article. Sometimes prone to armpits. Furthermore,
When molding with FRP, the surface opposite to the folds or protrusions of the molded product tends to be slightly depressed, a so-called "sink mark" phenomenon. This is believed to be caused by non-uniform shrinkage of the molding material. If a solvent-based paint is applied over these sink marks, the paint film will be uneven along the sink marks, which will impair the aesthetic appearance. Furthermore, another problem is that electrostatic coating is difficult when applying solvent-based paint to FRP. This is thought to be due to the extremely high electrical resistance of the FRP surface. Therefore, the present inventors have conducted extensive research to solve the above-mentioned problems in the coating technology for FRP articles, and have succeeded in painting FRP articles using a special technique without creating wrinkles or pinholes on the surface. but,
After further investigation, we discovered that the above-mentioned problems can be effectively solved by incorporating a liquid paint that does not contain water or solvent into the molding compound for FRP in advance, resulting in the present invention. I've reached it. That is, the molding composition for FRP according to the present invention contains () unsaturated polyester resin 15 to 60
Weight%, () Reinforcement 15-60% by weight, () Filler
15 to 60% by weight, () 0.01 to 5% by weight of catalyst, and () (A) A liquid paint in which the main resin is a liquid epoxy resin and contains at least one of a phenol compound, a composite amine compound, an imidazole compound, and an amino resin as a curing agent. or (B) a liquid paint whose main resin is a liquid acrylic resin having a glycidyl group and which contains a dicarboxylic acid or an acid anhydride as a hardening agent and has a non-volatile content of 98% or more, 0.3 to 20% by weight.
It consists of Any unsaturated polyester resin commonly used as a molding compound for conventional FRP can be used as the resin component to be blended into the composition of the present invention. ~60% by weight, preferably
Use in the range of 20-50% by weight. If the amount of resin blended is too large, it will be difficult to maintain the shape of SMC, TMC, BMC, etc., and the strength of FRP will be low, which is undesirable.On the other hand, if the blended amount is too small, the fluidity during molding will be reduced. This is not preferable because the surface smoothness of FRP is poor. The reinforcing material (or reinforcing material) to be added to the composition of the present invention may be any reinforcing material commonly used in conventional molding compounds for FRP, such as glass having a diameter of 2 to 30 μm and a length of 5 to 50 mm. Fibers, carbon fibers, etc. can be used. These reinforcing materials can be used alone or in combination. These reinforcements are present in amounts ranging from 15 to 60 per total weight of the composition.
% by weight, preferably in the range of 20-50% by weight. If the amount of reinforcing material blended is too large, molding becomes difficult and fluidity decreases, which is undesirable.On the other hand, if the blended amount is too small, the strength of the FRP decreases, which is not preferable. The filler to be incorporated into the composition of the present invention may be any filler commonly used in conventional FRP molding compounds, such as powdered fillers such as calcium carbonate, barium sulfate, talc, kaolin, clay, and silica powder. Agents and the like can be used. These fillers can be used alone or in combination. These fillers are based on the total weight of the composition.
It is used in a range of 15 to 60% by weight, preferably 20 to 50% by weight. If the amount of filler added is too large, the strength will decrease and molding will become difficult, which is undesirable.
On the other hand, if the blending amount is too small, the shrinkage rate when cooling the molded product after molding will increase, and SMC, TMC,
This is not preferable because it becomes difficult to maintain the shape of BMC, etc. Catalyst (or curing agent) to be added to the composition of the present invention
Any catalyst commonly used as molding compound for conventional FRP, such as t-butyl perbenzoate, benzoyl peroxide, t-butyl peroxide, etc.
Peroxides that decompose at temperatures of about 100 to 160°C can be used. These catalysts can be used alone or in combination. These catalysts are used in an amount of 0.01 to 5% by weight, preferably 0.1 to 2% by weight, based on the total weight of the composition. If the amount of catalyst blended is too large, the flow time of the compound will be shortened, making molding difficult, which is undesirable.On the other hand, if the blended amount is too small, the resin will not be cured sufficiently, resulting in a decrease in strength. Undesirable. The molding composition for FRP of the present invention contains, in addition to the above-mentioned general ingredients for FRP, a liquid paint that does not contain water or solvent. The liquid paint that can be used in the present invention is a paint that contains as main components, for example, a liquid epoxy resin, a phenol compound, a complex amine compound, an imidazole compound, and an amino resin, and is substantially free of water and solvent. The paint itself is already known. In addition, if water and solvent are included, the water and solvent will evaporate during compression molding, so
This is undesirable because it causes pinholes and wrinkles on the surface of the FRP article. The liquid paint mentioned here is one in which the main resin is liquid, with a liquid or solid curing agent, and if necessary, pigments, additives, and curing accelerators, and the non-volatile content is 98% or more. It refers to something. The liquid paint used in the present invention may further include a liquid paint whose main resin is a liquid acrylic resin having a glycidyl group and which contains a dicarboxylic acid or an acid anhydride as a curing agent. It is preferable that these combinations do not produce reaction products during the curing reaction. These compositions include known inorganic pigments, organic pigments,
Additives can be added. These liquid paints contain 0.3 to 20% of the total weight of the composition.
It is used in an amount of 1 to 20% by weight, preferably 1 to 20% by weight. If the amount of liquid paint is too large, SMC and
FRP molded because it can no longer maintain the shape of BMC
This is undesirable because the strength of the FRP product decreases, and conversely, if the amount is too small, wrinkles and pinholes may occur when a solvent-based paint is applied to an FRP article, which is undesirable. In addition to the above-mentioned essential ingredients, the FRP molding composition of the present invention includes commonly used optional ingredients,
For example, pigments, crystal nucleating agents, plasticizers, mold release agents, lubricants,
Heat stabilizers, antioxidants, ultraviolet absorbers, flame retardants, polymerization inhibitors, etc. can be added. The molding composition for FRP according to the present invention can be prepared into any shape such as a sheet, block, or rod by the same method as conventional molding compounds for FRP. An example of such a preparation method is to uniformly mix a resin, water, and solvent-free liquid paint, filler, catalyst, and other compositions using a Henschel mixer, and then impregnate the reinforcing agent to form BMC. Alternatively, SMC can be obtained by placing this BMC between two sheets of polyethylene and rolling it to an appropriate thickness, for example, 3 mm.
These BMC and SMC can also be used after aging at 40° C. for 48 hours, for example. The molding composition for FRP according to the present invention is generally applied to a mold of a desired shape with a release agent in advance, and then applied in the form of a sheet or cut, or in the form of a lump or rod. A fixed amount can be inserted and compression molded using a general method using a compression press. Compression molding is performed under conditions that are almost the same as general FRP molding conditions or under general conditions to ensure that the liquid paint components are completely cured in the FRP product.
Compared to FRP molding conditions, it can be carried out over a slightly longer period of time. For example, a temperature range of 120 to 160°C, a pressure of 3 to 100 kg/cm ² and a time of 2 to 30 minutes is selected depending on the thickness and shape of the molded product, the type and amount of the resin, catalyst and liquid paint used, etc. be able to. In addition, compression molded FRP can be further processed, for example.
It can also be sufficiently hardened by baking at a temperature of 120 to 170°C for 1 to 30 minutes. In this way, if the molding composition for FRP of the present invention is used, there is no problem of "sink",
It is possible to obtain an FRP article that has excellent surface smoothness and allows a coating film to be formed on the surface without wrinkles or pinholes. This product has sufficient performance as it is, such as surface smoothness, weather resistance, and abrasion resistance, but in order to further enhance the aesthetic appearance and provide other desired properties, it is necessary to apply it on top of the liquid paint film. A solid color or metallic color paint (for example, a solvent-based paint) can be suitably applied as a top coat according to conventional methods. Furthermore, by incorporating, for example, 1 to 20% by weight of a conductive substance such as carbon black, graphite, zinc powder, or antistatic agent into the liquid paint, the top coat can be easily and effectively electrostatically applied. Hereinafter, the present invention will be explained in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. In addition, in the following examples, "parts" indicate "parts by weight." Example 1 30 parts of unsaturated polyester resin (Polymer 6409 manufactured by Takeda Pharmaceutical Co., Ltd.), 40 parts of calcium carbonate powder (Whiten B manufactured by Shiraishi Calcium), 0.3 parts of t-butyl perbenzoate, 1 part of zinc stearate, 1 part of polyethylene powder, One part of magnesium oxide powder and five parts of the prescribed paint were mixed for one minute in a Henschel mixer. This mixture was spread on a polyethylene sheet with a thickness of 0.05 mm to a thickness of about 5 mm, and 30 parts of glass fiber (diameter 15μ and length 26 mm) was uniformly spread over this drawn mixture to 70 parts of this mixture. The glass fibers were impregnated with the mixture. Furthermore, a polyethylene sheet with a thickness of 0.05 mm was placed on top of this and passed through a roll to obtain a sheet composition with a thickness of 3 mm. This sheet-like composition was wrapped in aluminum foil and kept at 46° C. for 48 hours for aging to obtain a molding compound for FRP. A stainless steel mold with an internal thickness of 6 mm, width of 150 mm, and length of 200 mm was heated in a hot press with the upper surface adjusted to 160°C and the lower surface adjusted to 145°C. After coating the inner surface of the mold with a mold release agent (Mirror Glaze manufactured by Mirror Glite Polish), 350 g of the above molding compound for FRP was charged and compression molded at a pressure of 30 kg/cm ² for 8 minutes. The molded product was removed from the mold, and the surface of the molded product heated at 160°C was sprayed with 35μ of solvent-based paint (Olga 100OG-50 Sietland White NH-61 manufactured by Nippon Paint).
After setting for 10 minutes, it was baked at 150°C for 20 minutes.
Table 1 shows the appearance after molding and after painting with solvent paint.

【table】

[Table] Example 2 Instead of the molding compound for FRP used in Example 1, a molding compound for FRP having the following composition was manufactured in the same manner as in Example 1. Unsaturated polyester resin (Polymer 6409 manufactured by Takeda Pharmaceutical Co., Ltd.) 40 parts Calcium carbonate powder (Whiten B manufactured by Shiraishi Calcium) 20 parts Talc 10 parts Tertiary butyl perbenzoate 0.5 parts Zinc stearate 0.5 parts Polyethylene powder 0.5 parts Magnesium oxide powder 1 part Paint Composition of 10 parts glass fiber (diameter 15μ and length 26mm) or more
35 parts for 65 parts A mold for producing a T-shaped molded product with the shape and dimensions shown in Figure 1 was heated at 160°C on the top surface using a hot press.
The lower side was heated to 145°C. After applying a mold release agent to the inner surface of the mold, 350 g of the above molding compound for FRP was charged and compression molded for 8 minutes at a pressure of 30 kg/cm ² . Remove the molded product from the mold and
A 35μ solvent-based paint (same as in Example 1) was spray-coated on the surface of the molded product heated and molded at 150°C, and after setting for 10 minutes, it was baked at 150°C for 20 minutes. Table 2 shows the appearance after molding and after painting with solvent-based paint.

【table】 [Brief explanation of drawings]

FIG. 1 is a drawing showing the dimensions of a T-shaped molded product for testing the presence or absence of "sink marks" in molded products in Examples and Comparative Examples of the present invention.

Claims (1)

[Claims] 1 () Unsaturated polyester resin 15-60% by weight, () Reinforcement material 15-60% by weight, () Filler 15-60% by weight
60% by weight, () catalyst 0.01-5% by weight and ()
(A) A liquid paint whose main resin is a liquid epoxy resin and contains at least one of a phenol compound, a complex amine compound, an imidazole compound, and an amino resin as a curing agent; or (B) A liquid paint whose main resin is a liquid acrylic resin having a glycidyl group and whose main resin is a dicarbonate resin. A molding composition for FRP comprising 0.3 to 20% by weight of a liquid paint containing an acid or an acid anhydride as a hardening agent and having a non-volatile content of 98% or more.