JPH10128788A - Fiber reinforced resin composite body and preparation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for obtaining an entirely uniform fiber reinforced resin composite body without a deviation of a fiber reinforced material that is being molded in reaction injection molding. SOLUTION: A manufacturing method for obtaining a fiber reinforced composite body comprising the steps of accommodating one or a plurality of mat-like reinforcing fibers and one or a plurality of mat- or net-like bodies that have a resin permeability higher than that of the mat-like reinforcing fibers in a reaction injection molding die 51 in a laminated fashion, closing the die 51, and injecting a reactive raw resin into the die 51, wherein the thickness of the laminated piece is greater than the depth of a cavity of the die 51 when it is closed, and wherein the modulus of elasticity in compression in the thickness direction of the mat-like body 55 or the net-like body 53 ranges from 0.4 to 8.0kgf/cm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a fiber-reinforced resin composite.

[0002]

2. Description of the Related Art Recently, a fiber-reinforced resin molded article has attracted attention as a member requiring high performance of light weight, high rigidity and high strength. Fiber-reinforced resin molded articles can be obtained by various molding methods. One of the methods is S-RIM (Struct
ual Reaction Injection Molding). S-RIM
Means that two or more types of low-molecular and low-viscosity reactive raw resin are mixed in a mixing head under pressure while the mat-like reinforcing fibers are contained in a mold, and simultaneously injected into the above-mentioned closed mold. This is a molding method in which a polymerization reaction is completed in a mold to obtain a molded product.

However, in the conventional molding method, there is a problem in that the flow of the resin at the time of injecting the raw material resin causes a displacement of the fiber reinforced material contained in the cavity of the mold.

In Japanese Patent Application Laid-Open No. 4-265712, a positioning projection is provided on a part of the outer peripheral edge of the fiber reinforced material contained in the cavity of the mold, and the projection is pressed against the inner wall of the cavity. A method has been proposed. However, in the above method, it is necessary to cut the fiber reinforced material in order to provide the overhanging portion, which requires man-hours for cutting the fiber reinforced material, and the raw material efficiency of the fiber reinforced material is deteriorated.
Further, since the overhanging portion is pressed against the inner wall portion of the cavity, the portion tends to be compressed, and there is a problem that impregnation of the resin becomes poor or the resin is easily deformed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in view of the above-mentioned circumstances. There is a way to provide.

[0006]

According to the present invention, there is provided a method for producing a fiber-reinforced resin composite, wherein one or a plurality of mat-like reinforcing fibers and a resin having a higher resin flowability than the mat-like reinforcing fibers are placed in a reaction injection molding die. A method for obtaining a fiber-reinforced resin composite by laminating and storing one or more mat-like bodies or net-like bodies having a high resin content, closing the mold and injecting the reactive raw material resin into the mold. Wherein the thickness of the laminate is greater than the cavity depth of the mold when the mold is clamped, and the compression elastic modulus in the thickness direction of the mat-like or net-like body is 0.
It is 4 to 8.0 kgf / cm ² .

The mat-like reinforcing fibers used in the present invention include, for example, glass fibers, carbon fibers, and aramid fibers in the form of a mat, such as chopped strand mats, continuous mats, and cloths.

As the mat-like body and the net-like body used in the present invention, those having higher resin flowability than the mat-like reinforcing fiber are used. Usually, the mat-like body itself has a resin circulation space, and in the case of a net-like body, the resin circulation space is formed by the net-like body and the mat-like reinforcing fibers. This resin flow space allows the injected resin to pass through with less flow resistance than the mat-like reinforcing fiber.

The above-mentioned mat-like body and net-like body need to have compressive elasticity in the direction perpendicular to the plane (thickness direction). The mat-like body is made of synthetic material such as polypropylene, polyethylene and nylon. Relatively coarse ones in which fibers are intertwined randomly or regularly. Examples of the mesh include a wire mesh.

One example of the mat-like body used in the present invention is a polypropylene continuous mat (hereinafter referred to as a PP mat) manufactured by using an apparatus as shown in FIG. The molten polypropylene resin is extruded from the plurality of nozzles 52 of the extruder 51 into the linear body 53, and the vibrating plate 54 is vibrated at right angles to the extruding direction to bend the uncured linear body 53. Put on P
A P mat 55 is obtained.

The reactive raw resin used in the present invention includes, for example, urethane resin in which isocyanate and polyol are mixed, epoxy resin in which bisphenol A type resin is mixed with acid anhydride type curing agent, dicyclopentadiene resin and the like. Can be Among them, urethane resins and dicyclopentadiene resins are preferably used.

[0012] In the production method of the present invention, for example, the mat-like body or the net-like body is laminated on one of the mat-like reinforcing fibers, or the mat-like body or the net-like body is placed between two mat-like reinforcing fibers. It is used as a laminate by sandwiching one body or alternately stacking mat-like reinforcing fibers and mat-like or net-like bodies. When high strength is desired, a plurality of mat-like reinforcing fibers are stacked and used as a laminate having the above configuration.

[0013] The thickness of the laminate is made larger than the cavity depth when the mold used for molding is closed. The ratio of the thickness of the laminate to the cavity depth is determined by the compression modulus of the mat or net used,
It is appropriately selected depending on the type of the mat-like reinforcing fiber used, the reactive raw material resin used, and the like, and is usually 1.1 to 2.
It is 0 times, preferably 1.2 to 1.5 times.

The above-mentioned cavity depth refers to a dimension in a thickness direction of a space formed when a mold is clamped.

When the laminate having the above thickness is placed in a mold and clamped, the compression elasticity of the mat-like or net-like body causes
The mat-like reinforcing fiber is pressed against the inner surface of the mold, and even if the raw material resin is injected by this force and the resin flow is applied,
No misalignment of the mat-like fiber reinforcement occurs. If the compression elastic modulus of the mat-like body or the net-like body is less than 0.4 kgf / cm ² , the pressing force of the mat-like reinforcing fibers against the inner surface of the mold tends to be insufficient, and the misalignment is likely to occur, and if it exceeds 8.0 kgf / cm ^2. Since the pressing force is too strong, the mat-like reinforcing fibers may be compressed and the impregnation of the resin may be deteriorated.
It is limited to 4-8.0 Kgf / cm ² , preferably 1.
0 to 5.0 Kgf / cm ² , more preferably 2.
It is 0 to 3.0 Kgf / cm ² .

The above-mentioned compression modulus can also be adjusted by adjusting the thickness and weight of the fibers forming the mat-shaped or reticulated body. When the weight per unit area is increased, the compression elastic modulus is increased. With the same weight per unit area, when the fiber is thickened, the compression elastic modulus is increased.

The above-mentioned compression modulus is JIS-K-7220.
It is a numerical value measured according to. That is, compressive stress-
It is calculated by the following equation using the initial straight line portion of the distortion curve. E = Δσ / Δε where E: compression modulus Kgf / cm ² Δσ: stress difference between two points on a straight line Kgf / cm ² Δε: difference in strain between the same two points

[0018]

As described above, the compression modulus is 0.4 to 8.0 kg.
Due to the compressive elasticity of the mat-like body or the net-like body of f / cm ² , the mat-like reinforcing fiber is pressed against the inner surface of the mold, and even if the raw material resin is injected and the flow of the resin is applied, the position of the mat-like reinforcing fiber is displaced. Does not occur.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

EXAMPLES Examples of the present invention will be described below together with comparative examples. Embodiment 1 FIG. 1 shows a mold 10 used in this embodiment. The mold 10 includes an upper mold 11 and a lower mold 12, and the lower mold 12 has an injection gate 1.
3 are provided. The cavity formed when the upper mold and the lower mold are combined and clamped has a width of 500 mm and a length of 1 mm.
It has a rectangular parallelepiped shape of 000 mm and a depth of 5 mm. Upper mold 11
Both the lower mold 12 and the lower mold 12 were heated to 70 ° C. with warm water, and a laminate formed by sandwiching one mat-like body with two mat-like reinforcing fibers in the lower mold 12 was sandwiched. The mold clamping pressure was 6 kgf / cm ² , and the dwell time was 7 minutes.

As the mat-like reinforcing fibers, glass continuous mats (M860, manufactured by Asahi Fiberglass Co., Ltd.)
9, weight per unit area: 600 g / m ² ). As the mat-like body, a PP mat (fiber diameter: 0.6 mm, thickness: 10 mm, weight basis weight: 600 g / m) manufactured using the apparatus shown in FIG.
² , a compression modulus of 2.3 kgf / cm ² ).

The mold was closed, and the raw urethane resin was injected from the injection gate 13. The resin used was a polyol (manufactured by Sumitomo Bayer Urethane Co., SBU polyol H523).
100 parts by weight and 180 parts by weight of isocyanate (manufactured by Sumitomo Bayer Urethane Co., Ltd., SBU Isocyanate 0389) were used by mixing them with a mixing head (not shown) installed just before the injection gate.

The obtained plate-like fiber reinforced resin composite (width 50
0 mm, length 1000 mm, thickness 5 mm)
As a result of performing a bending test according to K-7055, a bending strength of 10.2 kgf / mm ² and a flexural modulus of 344 kgf / mm were obtained.
mm ² .

Comparative Example 1 A glass continuous mat was used without using a PP mat.
A plate-like fiber reinforced resin composite was obtained in the same manner as in Example, except that the sheet was used. In the obtained composite 20, as shown in FIG. 2, a portion 21 not impregnated with the resin is formed at the end in the direction opposite to the injection gate, and the glass continuous mat is displaced by the flow of the resin, and the resin alone is used. There was a part 22.

Comparative Example 2 As a PP mat, a fiber diameter of 0.6 mm, a thickness of 10 mm,
Weight basis 260g / m ^Two, Compression elastic modulus 0.31 kgf /
cm^TwoExcept for the use of
A fiber-reinforced resin composite was obtained. The obtained composite 30 is shown in FIG.
As shown in the figure, the resin was impregnated to the end,
The continuous mat is displaced, and the resin-only part 31
occured.

Comparative Example 3 As a PP mat, a fiber diameter of 1.2 mm, a thickness of 10 mm,
Weight per unit area: 1500 g / m ² , compression modulus: 8.8 kgf /
A plate-like fiber-reinforced resin composite was obtained in the same manner as in Example, except that a resin having a particle size of cm ² was used. The obtained composite 40 is shown in FIG.
As shown in (1), no displacement of the glass continuous mat occurred, but portions 41 not impregnated with the resin were scattered.

[0026]

According to the method for producing a fiber-reinforced resin composite of the present invention, even if the raw resin is injected and the flow of the resin is applied, the position of the mat-shaped fiber reinforcing material does not shift, so that the raw resin is not used. A uniform fiber-reinforced resin composite can be obtained without generating an impregnated portion or a resin-only portion.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a mold used in the present invention.

FIG. 2 is a perspective view of a product obtained in Comparative Example 1.

FIG. 3 is a perspective view of a product obtained in Comparative Example 2.

FIG. 4 is a perspective view of a product obtained in Comparative Example 3.

FIG. 5 is a front view showing an example of an apparatus for manufacturing a mat-like body used in the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 Mold 11 Upper mold 12 Lower mold 13 Injection gate 20, 30, 40 Fiber reinforced resin composite 21, 41 Resin non-impregnated part 22, 31 Resin single part 51 Extrusion mold 52 Nozzle 53 Linear body 54 Vibrating plate 55 Mat body (PP mat)

Claims (1)

[Claims] In a reaction injection molding die, one or more mat-like reinforcing fibers and one or more mat-like or net-like bodies having higher resin flowability than the mat-like reinforcing fibers are laminated. A method for producing a fiber-reinforced resin composite by closing the mold and injecting the reactive raw material resin into the mold, wherein the thickness of the laminate is reduced when the mold is clamped. Greater than the cavity depth of the mold, the compression elastic modulus in the thickness direction of the mat-like or net-like body is 0.4 to 0.4;
A method for producing a fiber-reinforced resin composite, which has a weight of 8.0 kgf / cm ² .