JPH05148749A - Fiber-reinforced resin molded product - Google Patents

Abstract

PURPOSE:To obtain the subject molded product of high mechanical strength, prevented from interlaminar debonding by monolithically laminating plural sheets of a fibrous base material impregnated with a thermoplastic resin and by making unevennesses on the laminate surfaces and also by casting the thermoplastic resin on the recesses on at least one side of the laminate to make the surface flat. CONSTITUTION:A plain-woven roving cloth made using glass fiber roving is impregnated with a polypropylene resin as thermoplastic resin to form a prepreg material. Plural sheets of the prepreg material are then laminated and put to hot pressing into a monolithic laminate, and unevennesses of wavy or serrated shape in the sectional view are made on the laminate surfaces followed by casting the polypropylene resin on the recesses on at least one side of the laminate to make the surface flat, thus obtaining the objective resin molded product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced resin molded product which can be used in various fields including automobile parts such as bumpers, sunroof housings and seat back frames.

[0002]

2. Description of the Related Art Conventionally, a plurality of base materials obtained by impregnating a material such as glass fiber with a resin are laminated and molded into a desired shape on the market. Although these molded products are pressure-molded so that the laminated surface of the base material and the base material are in close contact with each other,
There is no constraint in the plate thickness direction by glass fibers or the like, and there is a problem that the stress applied to the molded product is directly transmitted to the laminated surfaces formed in parallel and delamination occurs to reduce the strength of the molded product.

As a molded article invented to prevent this delamination, there is one disclosed in Japanese Patent Publication No. 2985/1990. In this molded product, interlaminar reinforcing fibers consisting of short fibers are randomly inserted from the outer surface of the molded product in which the base material is laminated by using a jet flow, and a connecting state by the interlaminar reinforcing fibers is created between the layers, The delamination of the material is prevented.

[0004]

However, there is a limit to the thickness of the base material into which the short fibers can be inserted by using the jet flow, and when the base material reaches a certain number or more, the short fibers are inserted into the whole. It was not possible to completely prevent delamination. In addition, there is a problem that the number of processes is increased and another facility is required.

Therefore, it is a technical object of the present invention to provide a resin-reinforced molded product capable of preventing delamination regardless of the thickness of the base material and the molded product.

[0006]

[Constitution of the invention]

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the technical solution provided by the present invention comprises a plurality of base materials in which fibers are impregnated with a thermoplastic resin, which are laminated without a gap. The fiber-reinforced resin molded product is characterized in that the laminated surface of the material has irregularities, and preferably, the laminated surface of the base material has a wavy or sawtooth cross section.

As the fibers used for the substrate, inorganic fibers such as glass fibers and carbon fibers, organic fibers such as polyamide and highly stretched polyethylene, and metal fibers such as stainless steel and titanium can be used. Further, as the form of the fiber, continuous fiber such as roving, or roving cloth woven by roving can be used.

As the thermoplastic resin, polystyrene, polypropylene, polyethylene, AS resin, ABS resin,
ASA resin, polymethyl methacrylate 9 nylon, polyacetal, polycarbonate, polyethylene terephthalate, polyphenylene oxide, fluororesin, polyphenylene sulfide 9 polysulfone, polyether sulfone, polyether ketone, polyimide, polyarylate and the like can be used.

Regarding the height and the spread of the unevenness formed on the laminated surface, if the height of the unevenness is too large or too small, the base material cannot withstand the stress applied during pressure molding. , Especially on the pull side (projection side), it may be damaged or weakened during molding, but if the height of the unevenness is too small or the spread is too large, the molded product will be close to a flat surface and effective. Fades. For this reason, it is preferable that the unevenness formed on the molded product has a height equal to or greater than the thickness of the molded product, or that the unevenness has a cycle of one or more times. Further, as for the unevenness, only concave portions or convex portions may be randomly formed, or both concave portions and convex portions may be formed. Further, unevenness may be formed so as to have a wavy shape or a sawtooth shape as a whole, and any shape may be used as long as the laminated surface is not flat.

[0011]

The above-mentioned problem acts as follows. That is, in the present invention, the laminated surface of each laminated base material has unevenness and is not parallel, and each layer is unevenly laminated while maintaining the same interval and thickness, and at a constant distance from the outer surface of the molded product. Has no continuous laminated surface. Therefore, the stress applied to the molded product is dispersed in multiple layers without being concentrated in the same layer, and delamination becomes difficult.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a base material forming a reinforced resin molded product. The base material in the first embodiment is a prepreg material obtained by impregnating a roving cloth 2 in which glass fibers having a diameter of 13 μm are bundled into a plain weave with a basis weight of 200 g / m ² and 50% by weight of polypropylene resin 1 as a thermoplastic resin. 3 (PP-GF-SB manufactured by Mitsui Toatsu Chemicals, Inc.). Next, the prepreg material 3 is cut into 100 × 300 mm, and 10 sheets are laminated in the same direction as shown in FIG. 2 to obtain a prepreg laminated product 4 having a thickness of about 10 mm. This was set in the press machine 5 which had been preheated to 210 ° C. in a high temperature tank, and the mold temperature was 70 ° C., and the press pressure was 20 kg / cm ² .
Hold for a minute. The cross sections of the molding surfaces of the upper mold 5a and the lower mold 5b of the press machine 5 have the same sine waveform, and the cycle is 1
0 mm, amplitude 2 mm (height of unevenness from the center line is 1 m
m). Pressure-molded prepreg laminate 4
Is a fiber-reinforced resin molded product 6 having a wavy cross section with the same period and the same amplitude as the press machine 5, and its thickness is about 2 mm.

Fiber-reinforced resin molded product 6 thus formed
25mm across the wave and 70m in the direction parallel to the wave
It cut into the rectangle of the size of m, and performed the bending test shown in FIG.

The test conditions were that the fiber-reinforced resin molded product 6 was placed on a table 10 having a bending span of 45 mm, and the jig 9 was lowered from above the center at a bending speed of 1 mm / min. The test results are as shown in Table 1, bending strength 61 kg / mm ² ,
The bending elastic modulus was 3050 kg / mm ² , and the strength and elastic modulus could be improved by 20% or more as compared with the conventional one (Comparative Example 1) described later.

As the second embodiment, the same prepreg laminate 4 of the first embodiment is used, and a fiber having a sine waveform with a period of 10 mm and an amplitude of 6 mm (the height of the unevenness from the center line is 3 mm). The reinforced resin molded product was pressure molded. As the third embodiment, the same prepreg laminate as in the first and second embodiments is used, and the cycle is 10 mm as shown in FIG.
Then, a saw-toothed fiber-reinforced resin molded product 7 having an amplitude of 2 mm (the height of the unevenness from the center line is 1 mm) was pressure-molded. Further, as a comparative example, the same prepreg laminated product as in the above-mentioned example was used, and a flat fiber-reinforced resin molded product 8 having no unevenness was molded under the same conditions of pressure and the like. The same tests as in Example 1 were performed on the second and third examples and the comparative example. The test results are shown in Table 1.

[0017]

[Table 1]

Regarding the evaluation, the case where the bending strength and the bending elastic modulus were improved by 20% or more compared with Comparative Example 1 was marked with ◯. As described above, all three of the first to third examples have the flexural strength and the flexural modulus of the comparative example, which are increased by 20% of the flexural modulus, and the high strength and the high elastic modulus, It has a structure that is strong against stress and is unlikely to peel off between layers. This is because in Comparative Example 1, since the respective laminated surfaces are flat and the laminated intervals are parallel, the stress applied to the laminated product runs between the parallel laminated layers as shown in FIG. In the embodiment, as shown in FIG. 7, since each laminated surface is not parallel to the extending direction of the molded product but has a corrugated shape, stress applied from the outside of the molded product does not concentrate on the same layer. , And has the effect of suppressing the delamination 12 by being dispersed in multiple layers to the minimum. As a result, the durability of the fiber-reinforced resin molded product is improved and the strength is also improved.

In the present embodiment, the molded product has a sinusoidal or sawtooth cross section.
The laminated surface does not have to be a flat surface as a whole, and may have a shape having a plurality of irregularities. When the cross section of the base material has a corrugated shape such as a sine shape or a sawtooth shape, the strength and elastic modulus can be improved as a whole, as compared with the case where partial unevenness is provided on the laminated surface.

Further, when a fiber reinforced resin molded product having a flat outer surface is required, it is used for molding the prepreg material in the groove-shaped recess 6a of the molded product as shown in FIG. By filling the same resin 10 as described above and molding so that the surface becomes a flat surface, it is possible to obtain a molded product that is strong in delamination and strength and has no unevenness on the surface.

[0021]

EFFECTS OF THE INVENTION According to the present invention, the unevenness provided on the laminated surface makes it difficult to cause delamination, and the strength and durability of the resin-reinforced molded product can be improved.

Further, when the base material has a wavy or sawtooth cross section, it is possible to prevent delamination and improve the strength as compared with the case where partial unevenness is provided.

Further, it is possible to improve both strength and elastic force by the conventional process and conventional material without requiring an extra process after the pressure processing.

[Brief description of drawings]

FIG. 1 is a perspective view of a prepreg material constituting a fiber-reinforced resin molded product according to an embodiment of the present invention.

FIG. 2 shows a perspective view of a prepreg laminate according to an embodiment of the present invention.

FIG. 3 (a) shows a mold for press-molding the fiber-reinforced resin molded product of the first embodiment, and FIG. 3 (b) shows FIG.
The enlarged view of the A section of (a) is shown.

FIG. 4 is a partial perspective view of the fiber-reinforced resin molded product of the first embodiment.

FIG. 5 shows a partial perspective view of a fiber-reinforced resin molded product of a third embodiment.

FIG. 6 shows the test status of the fiber-reinforced resin molded products of the present example and the comparative example.

FIG. 7 shows a partial cross-sectional view of a fiber-reinforced resin molded product of this example.

FIG. 8 shows another embodiment of the present invention, and is a partial perspective view of a fiber-reinforced resin molded product which is molded so that the recess is filled with resin and the outer surface becomes flat.

FIG. 9 shows a partial cross-sectional view of a fiber-reinforced resin molded product of a comparative example.

[Explanation of symbols]

 1 polypropylene (thermoplastic resin) 2 roving cloth (fiber) 3 prepreg material (base material) 4 prepreg laminated product (base material in which a plurality of sheets are laminated) 6,7 fiber-reinforced resin molded product 6a groove-like recess

Claims (3)

[Claims] 1. A fiber-reinforced resin molded article, characterized in that a plurality of base materials, in which fibers are impregnated with a thermoplastic resin, are stacked without a gap, and the base material has a laminated surface with irregularities. 2. The fiber-reinforced resin molded product according to claim 1, wherein the cross section of the laminated surface of the base material is wavy or sawtooth. 3. The fiber-reinforced resin molded product according to claim 1, wherein the thermoplastic resin is flown into a concave portion of at least one surface of the fiber-reinforced resin molded product, and the outer surface is flat.