JPS62146929A - Fiber-reinforced composite material - Google Patents

Abstract

PURPOSE:To obtain a fiber-reinforced composite material excellent in moldability, mechanical property and weathering resistance and good in appearance, by mixing a mixture comprising a specified resin, a polyvinyl oligomer and a vinyl monomer with a reinforcing fiber, a metal oxide, etc. CONSTITUTION:A mixture is obtained by mixing 10-40wt% methacrylate copolymer resin containing 0.05-1.0mol, per 1,000g of resin, of groups of the formula (wherein X is an aromatic group or an alicyclic group) as side chains with 5-40wt% polyvinyl oligomer having at least two (meth)acryloyl groups in the molecule and 20-85wt% vinyl monomer (e.g., methyl methacrylate). This mixture is further mixed with a reinforcing fiber such as glass fiber, a bivalent metal oxide or hydroxide and, optionally, a radical polymerization initiator, a filler, a shrinkage-lowering aid, etc., and th obtained mixture is thickened to a viscosity at 25 deg.C of 100,000-1,500,000 P and molded by heating to 120-160 deg.C at a pressure of 20-250kb/cm<2> for 2-10 min.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a novel product which can be formed at high speed under heating and pressurizing conditions and is particularly suitable for outdoor use in vehicle parts, building materials, road materials, etc. The present invention relates to fiber-reinforced composite materials.

[Conventional technology]

Conventionally, TA fiber-reinforced composite materials have been widely used in vehicle components, building materials, housing equipment, etc. because they can add mechanical strength to the easy processability and non-corrosion properties of plastics. Unsaturated polyester resins and epoxy resins are widely used as resin components for these fiber-reinforced composite materials, but both have poor weather resistance and must be painted when used outdoors. There has been a desire to provide fiber-reinforced composite materials that do not.

On the other hand, molding methods for fiber-reinforced composite materials include the Handley Atsushi method, resin injection method, cold press method, pultrusion method, filament winding method, sheet molding method (SMC method), bulk molding method (BMC method), etc. Although various proposals have been made, the SMC method and BMC method are excellent for rapidly producing molded products of arbitrary shapes, and these methods have excellent weather resistance that can be used outdoors. Fiber-reinforced composite materials that have a similar structure are particularly desirable.

In order to meet these demands, for example, JP-A-49-
104937, an acrylic composite material consisting of a methacrylic acid ester monomer and a methacrylic resin has been proposed, but in conventional methods, it is not suitable for hot pressure molding such as SMC method and BMC method. The viscosity characteristics before molding and the flow characteristics during molding cannot be obtained, so it has not been put into practical use.

[Problem that the invention seeks to solve]

The present invention uses SMC fiber reinforced composite materials with excellent weather resistance.
The aim is to improve the viscosity characteristics before molding and the flow characteristics during molding to make them suitable for the above-mentioned method.

[Means for solving problems]

The fiber-reinforced composite material of the present invention has (A) 10GO-X-C:OOH (in the formula, X is an aromatic group or alicyclic group) in the side chain of 0.05 to 0.05 to 1000 g of resin.
Methacrylic acid ester copolymer resin 1 containing 1.0 mol
0 to 4% by weight, (B) 5 to 40% by weight of a polyvalent vinyl oligomer containing two or more acryloyl or methacryloyl groups in one molecule, and (C) 20 to 85% by weight of vinyl monomer. It is formed by mixing reinforcing fibers and divalent metal oxides or hydroxides into a compound, and then heating and press-molding the mixture.

The above copolymer resin (A) has a specific structure, that is, -
It is characterized by having 0CO-X-COOH (X is an aromatic group or an alicyclic group) in a side chain. This structure can be used with hydroxy-containing vinyl monomers such as hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, hydroxybutyl methacrylate, hydroxybutyl acrylate, and hydroxy-containing vinyl monomers such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydroanhydride. By copolymerizing monomers obtained by addition reaction with aromatic or alicyclic acid anhydrides such as phthalic acid, methyltetrahydrophthalic anhydride, and nadic anhydride, or by copolymerizing the above-mentioned hydroxyl group-containing vinyl monomers. It can be obtained by addition reaction of the above-mentioned acid anhydrides to the copolymer. The monomer component having the above structure is preferably acrylic esters or methacrylic esters, with methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, etc. being particularly preferred. Yes, other methacrylic esters, acrylic esters, aromatic monomers such as styrene, α-methylstyrene, vinyltoluene, paramethylstyrene, chlorostyrene, vinyl esters such as vinyl acetate and vinyl propionate, Vinyl halide monomers such as vinyl chloride and vinylidene chloride, unsaturated nitriles such as acrylonitrile and methacryloyl groups, etc. may be used in combination as copolymerization components.

The content of carboxyl groups with the above-mentioned specific structure in the copolymer resin is 0.05 to 1.0 mol per 1000 g of resin, and within this range, appropriate viscosity characteristics before molding and flow characteristics during molding can be obtained. It will be done. The carboxyl group in the above structure ionically bonds with the divalent metal oxide or hydroxide, efficiently thickens the resin component, and provides appropriate viscosity characteristics before molding (
It is believed that the ionic bonds are moderately dissociated during heating and exhibit good flow characteristics. It exhibits properties that could not be achieved with polymeric copolymer resins.

The above specific carboxyl group content is 1000g of resin
0.0 middle child. If it is less than 1.0 mol, the viscosity will be insufficiently thickened and handling before molding will be difficult, and if it is more than 1.0 mol, the flow characteristics during molding will deteriorate and the water resistance of the molded composite material will decrease, making it unsuitable. . In particular, 0.2 to 0.7 mol is suitable.

As the polyvalent vinyl oligomer (B), an esterified product of polyhydric alcohol and acrylic acid or methacrylic acid is used, such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, diprobylene glycol, butanediol, bentanediol, Hexanediol, hydrogenated bisphenol A
In addition to polyhydric alcohols such as , trimethylolethane, trimethylolpropane, pentaerythritol, dipentol, sorbitol, and trishydroxyethyl isocyanurate, polyglycidyl ethers of the above polyhydric alcohols, alicyclic polyepoxides, and aromatic carboxyl Acid diglycidyl esters are also useful as polyhydric alcohol components. The polyvalent vinyl oligomer (B) above imparts heat resistance to the molded product and also facilitates demolding from the mold during molding.

As the vinyl monomer (C), methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, and isopropyl methacrylate are preferably used, and aromatic monomers such as styrene can also be used in combination. It is preferable that the methacrylic acid ester accounts for 50% by weight or more of the monomer. These vinyl monomers (C) serve as a reactive diluent that sufficiently impregnates the reinforcing fibers with the resin component.

The blending ratio of the components (A), (B) and (C) is (
A) is 10-40% by weight, (B) is 5-40% by weight, (
C) exhibits good moldability and physical properties of molded products at 20 to 85% by weight, but when (A) is at 15 to 30% by weight and (B) is at 1
Most preferably, the amount of (C) is 0 to 30% by weight, and 40 to 75% by weight.

The resin-forming components (A), (B) and (C) include reinforcing fibers such as glass fibers and carbon fibers, and oxides or hydroxides of divalent metals as thickeners, such as magnesium. , calcilum, zinc, strontium, etc., and known radical polymerization initiators, and if necessary, fillers such as calcium carbonate, barium sulfate, talc, silica, alumina, crushed sand, glass spheres, etc., and low-shrinkage auxiliary agents. , a coloring agent, a mold release agent, etc. are mixed, and the mixture is usually maintained at a temperature of room temperature to 50°C to form a liquid formulation, with a viscosity of 10°C at 25°C.
The viscosity is increased to 1,000,000 to 1,500,000 voids, and the material is made into a form that is easy to cut and charge into a mold for practical use.

Molding is usually carried out in a mold heated to 120 to 160°C by applying pressure of 20 to 250 kg/cm' for 2 to 10 minutes to simultaneously flow and harden the fiber-reinforced material of the present invention. Obtain composite materials.

〔Effect of the invention〕

By using a copolymer resin with a specific structure, the present invention achieves extremely good moldability in heat-pressure molding, and provides fiber-reinforced composites with good appearance, mechanical properties, and extremely good weather resistance. I was able to obtain the materials.

〔Example〕

EXAMPLES The present invention will be specifically described below with reference to Examples.

In the example, 10 parts by weight of azobisisobutyronitrile was dissolved in the monomer mixture shown in experiment numbers 1 to 6 (6 is a comparative example) in Table 1,
The above monomer mixture was added continuously over a period of 4 hours to a reactor containing 1000 parts by weight of toluene each, during which the temperature of the reactants was maintained at 90-95°C, and after the addition was completed, azobisisobutyro 10 parts by weight of nitrile was further added and the mixture was heated and stirred at the same temperature for 3 hours. Thereafter, the reaction solution was transferred to an evaporator and heated under reduced pressure to evaporate toluene to obtain a solid resin. The carboxyl group content of the resulting resin was measured by caustic potassium titration and is also listed in Table 1.

Table 1 Note 1) The carboxyl group-containing monomers used in resin numbers (1) to (6) are as shown in Table 1.

Sheet molding compound experiment number 1~
Using each of the resins listed in Table 6, polyvalent vinyl oligomers, vinyl monomers, polymerization initiators, thickeners, fillers, low shrinkage agents, and mold release agents shown in Table 2 were mixed and dissolved, and the mixture was applied onto a polyethylene film. Glass m fibers cut to 25.4 mm were continuously and evenly sprinkled from the top, covered with another polyethylene film, rolled up, and left at 40°C for 24 hours to form a sheet molding compound. was manufactured. Table 2 shows the temperature of the mixed liquid at 40° for 24 hours before adding glass fiber.
The viscosity after standing (measured at 40° C.) and the glass fiber content of the sheet molding compound of each experimental number determined by the combustion method are also listed.

/ Bi / Snow Each of the above sheet molding compounds was added to the upper mold (
145℃) and the lower mold (140℃),
Pressure and heat molding was performed at a pressure of 100 kg/am' for 5 minutes to obtain a molded product with a thickness of about 4 mm.

In Experiment No. 7, as a comparative example, a molded product was obtained using a commercially available sheet molding compound based on unsaturated polyester under the same conditions as above. Table 3 shows appearance, gloss, bending strength,
Flexural modulus, weather resistance (Sunshine Weather Off-Ter 5)
The gloss retention rate after irradiation for 00 hours was measured and described.

Table 3

Claims (1)

[Claims] 1. (A) -OCO-X-COOH (in the formula, X is an aromatic group or alicyclic group) in the side chain in 0.05 to 0.05 to 1000 g of resin
Methacrylic acid ester copolymer resin 1 containing 1.0 mol
0 to 40% by weight, (B) 5 to 40% by weight of a polyvalent vinyl oligomer containing two or more acryloyl or methacryloyl groups in one molecule, and (C) 20 to 85% by weight of vinyl monomer. A fiber-reinforced composite material made by mixing reinforcing fibers and divalent metal oxides or hydroxides, thickening the mixture, and then heating and press-molding the mixture.