JP3164652B2 - Fiber reinforced plastic products with improved weather resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced plastic product having excellent weather resistance and appearance quality.

[0002]

2. Description of the Related Art Fiber-reinforced plastics are composed of thermosetting resins and reinforcing fibers such as glass fibers. Containers such as tanks and containers are excellent in terms of their excellent mechanical strength, moldability, and economy. It is used for a wide range of applications such as and various building materials.

However, there is a problem that FRP products are yellowed and glass fibers are exposed on a surface layer when exposed to ultraviolet rays for a long period of time outdoors. Therefore, there have been proposed FRP products in which a polyvinylidene fluoride (hereinafter referred to as “PVDF”) film is laminated on the surface, or an FRP product in which a resin to which an ultraviolet absorber or the like is added is laminated as a surface layer.

However, in the former case, PVDF is applied to the surface of a corrugated plate by urethane-based adhesive.
Since the film is bonded and laminated, the PVDF film may be peeled off.
The molding compound (hereinafter, referred to as "SMC") has a problem that since the surface resin layer is thin, sufficient weather resistance cannot be obtained even if an ultraviolet absorber is added to, for example, a polyester resin constituting the SMC.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its gist is to provide an uncured SM obtained by impregnating a glass fiber base material with an unsaturated polyester resin composition.
A prepreg made by impregnating a mat-shaped or cloth-shaped glass fiber with a methyl-methacrylate-modified unsaturated polyester resin on the surface of C, and heated / pressurized, wherein the fiber is a weather-resistant fiber-reinforced plastic product. It is.

Uncured SM serving as a substrate in the present invention
C is a monofilament for reinforcement such as chopped roving glass or chopped strand mat formed by adding a resin compound obtained by adding a filler and a curing agent mainly containing calcium carbonate powder to an unsaturated polyester resin using a usual styrene monomer. Impregnated into a glass fiber base material.

The prepreg to be laminated on the surface of the SMC is made of a compound of an unsaturated polyester resin obtained by replacing a part of the styrene monomer with methyl methacrylate and modifying the same with a glass fiber base such as a continuous glass fiber mat or glass fiber cloth. The material is impregnated. What is important here is that the glass fiber substrate in the prepreg is
It is a continuous long-fiber-shaped one, and has a function of preventing the end of the glass fiber from protruding when the resin layer on the surface is peeled off and suppressing the exposure of the glass fiber from the SMC inner layer part. .

The product of the present invention is obtained by laminating the above prepreg on the above SMC substrate and pressing by heating. The molded product obtained by laminating and integrating has a methyl methacrylate-modified polyester resin layer on the surface and is a continuous glass. It has a layer structure having an ordinary SMC layer via a fiber base material.

[0009]

Example: A chopped roving glass of 30 wt% was impregnated with 70 wt% of a resin compound having a compounding ratio shown in Table 1 obtained by adding a filler such as calcium carbonate, a dispersant, a curing agent, etc. to an unsaturated polyester resin. A cured SMC is obtained.

[0010]

[Table 1]

On the other hand, a cloth made of a long fiber glass fiber is impregnated with a compound of a modified unsaturated polyester resin in which 30% of about 50% of a styrene monomer contained in the unsaturated polyester resin is substituted with methyl methacrylate. To obtain an uncured prepreg.

Next, four 1.5 mm thick SMCs (6
(thickness), a single prepreg having a thickness of 0.5 mm is laminated, a laminated body having a total laminated thickness of 6.5 mm is charged on a lower die of a press die, and the upper die is closed. C, a lower mold temperature of 130 ° C., a pressure of 50 kg / cm ² , and a pressure holding time of 5 minutes were pressed to obtain a fiber-reinforced plastic molded article having excellent appearance quality.

On the other hand, a cloth made of long fiber glass fiber was laminated and formed on the SMC having the same thickness under the same press conditions as the comparative example in place of the prepreg.

In the comparative example obtained, the glass fibers were exposed on the surface, resulting in poor appearance and poor weather resistance. However, in the example of the present invention, the surface was concealed by the modified unsaturated polyester resin layer. Since the glass fiber inside the SMC was pressed down, the appearance was excellent and the weather resistance was greatly improved.

[0015]

The present invention has the above-mentioned structure, and has the following effects. That is, since the long fibrous glass mat or cloth is concealed by the modified unsaturated polyester resin substituted with methyl methacrylate, the molded article surface layer improves weather resistance, and may cause protrusion of glass fiber ends on the surface. No appearance quality is excellent.

Claims (1)

(57) [Claims] 1. An uncured sheet molding compound obtained by impregnating a glass fiber base material with an unsaturated polyester resin composition, a mat-shaped or cloth-shaped glass fiber and a methyl-methacrylate-modified unsaturated fiber. Laminate prepreg impregnated with polyester resin and heat /
A weather-resistant fiber-reinforced plastic product characterized by being pressurized .