JPH1015978A - Manufacture of fiber reinforced resin composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a raw material resin non-impregnated area, and a weld line from generating when a fiber reinforced resin composite having an area of a different thickness is formed. SOLUTION: In a mold for reaction-injection molding, two sheets of reinforcing fiber mats 16 and two sheets of mat-like bodies 14, 15 arranged side by side and having a resin flowability higher than that of the reinforcing fiber mats 16 are laminated and and disposed in such a manner that the former is placed on the outside, and then, the mold is closed, and a reactive raw material resin is injected in the mold. By doing so, the raw material resin is made to enter the resin flowing space of the mat-from bodies, and at the same time, the reinforced fiber mats are impregnated with the raw material resin entered the resin flowing space to form this fiber reinforced resin composite body having an area of a different thickness. In this case, at an area where a thin-sectioned part is formed, the mat-like bodies with a higher porosity are arranged, and at an area where a heavy-sectioned part is formed, the mat-like bodies with a lower porosity are arranged.

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 low-molecular and low-viscosity liquid monomers are mixed in a mixing head under pressure while the mat-like reinforcing fibers are arranged in a mold, and simultaneously injected into a closed mold,
This is a molding method in which a polymerization reaction is completed in a mold to obtain a molded product.

[0003] In the S-RIM, in order to improve the above-mentioned performance of a fiber-reinforced resin molded product, the fiber content may be increased. However, the mat-like reinforcing fiber impregnates the raw resin into the mat-like reinforcing fiber at a low pressure irrespective of the high density, so that if the fiber content is high, the flow resistance of the raw resin increases, and the raw resin increases. Is not sufficiently impregnated into the mat-like reinforcing fibers. Therefore, the fiber content cannot be made too high (conventionally less than 20% by weight).

Further, when there are portions having different thicknesses in a molded product, a portion having a relatively large thickness is more likely to flow than a portion having a relatively small thickness. Because the resistance is low, the raw material resin is likely to flow preferentially to the thicker part, and to the thinner part,
An unimpregnated portion of the raw resin may occur.

By the way, when the raw material resin is considered as a non-Newtonian fluid, in the case of a rectangular flow path, if the flow rate is Q, the thickness of the rectangular flow path is H, the pressure loss is ΔP, and the flow characteristic of the raw resin is a (dimensionless), , Q = KH ^{a + 2} ΔP ^a (K: constant), and the thickness H greatly affects the flow of the raw material resin.

[0006]

In order to solve the above-mentioned problem, before injecting the raw material resin into the mold, the fibers in the high fiber content portion or the hardly impregnated portion of the raw material resin are preliminarily added to the fiber. A method of impregnating a resin has been proposed (see JP-A-2-215510).

However, since a time is required for closing the mold and injecting and filling the material resin into the mold, when a urethane resin having a high reactivity is used as the material resin, in the above-mentioned proposed method, the fibers are previously added to the fibers. The impregnated raw resin is cured before the injection filling, and the part becomes a weld line, and the molding process becomes complicated. An object of the present invention is to provide a method for producing a fiber-reinforced resin composite having high strength overall even when there are different thickness portions.

[0008]

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. One or a plurality of mats or nets having a high height are stacked and housed, and then the mold is closed and the reactive resin material is injected into the molds, whereby the raw resin is matted or meshed. In the resin flow space or the mat-like reinforcing fiber, the resin-filled space formed by the mat-like body or the net-like body and infiltrate the resin-filled space into the resin-filled space into the resin-filled space. A method for producing a fiber-reinforced resin composite having a portion, wherein a mat-like body or a net-like body having a high porosity is arranged in a portion where a relatively thin wall is formed, and a relatively thick wall is formed. Be done Min is characterized in that the porosity arranging the lower mat-shaped body or reticulate body.

When the thickness of the fiber-reinforced resin composite changes continuously, the porosity of the mat-shaped or net-like body is also changed continuously according to the change in the thickness, and the thickness of the fiber-reinforced resin composite is changed. If the thickness changes discontinuously, the porosity of the mat or reticulate also changes discontinuously.

As the mat-like reinforcing fiber, a glass fiber, a carbon fiber, an aramid fiber or the like formed into a mat body such as a chopped strand mat, a continuous mat, a cloth or the like has an elastic modulus of 3000 kg / mm ² and a strength of 200 kg / m ² .
It is preferable to use one having a thickness of ² mm2 or more. If it is less than this value, there is no reinforcing effect even if the fiber content is increased.

The basis weight of one mat-like reinforcing fiber is desirably 300 to 900 g / m ² . 300g / m
^If it is less than ² , the mat becomes coarse and the variation in strength becomes large, and if it exceeds 900 g / m ² , the impregnating property of the raw material resin becomes poor, and a portion of only the mat-like reinforcing fibers is generated.

As the mat-like body and the net-like body, those having higher resin circulation than the mat-like reinforcing fiber are used.
Usually, the mat-shaped body itself has a resin circulation space,
In the reticulated body, a resin circulation space is formed by the reticulated body and the mat-like reinforcing fibers, but the reverse case may occur in a special product. In the resin circulation space, the reactive raw material resin can pass with less flow resistance than the mat-like reinforcing fiber. The mat-like body and the net-like body preferably increase the strength of the fiber-reinforced resin composite, but this is not always necessary. A specific example of the mat-like body is a relatively coarse one in which synthetic fibers such as polypropylene are entangled randomly or regularly. As a specific example of the net-like body, there is a wire net.

When there is no mat or net, 300 g
With a mat-like reinforcing fiber having a basis weight exceeding / m ² , it becomes difficult to impregnate the raw resin. Specific examples of the reactive raw material resin include a urethane resin in which isocyanate and a polyol are mixed, an epoxy resin in which a bisphenol A type resin and an acid anhydride-based curing agent are mixed, and a dicyclopentadiene resin. Among them, urethane resins and dicyclopentadiene resins are preferably used.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The box-shaped fiber-reinforced resin composite (A) shown in FIG.
Form using (3). Box-shaped fiber reinforced resin composite (A)
Has a pair of opposing thin side walls (1) and another pair of opposing thick side walls (2).

The mold for reaction injection molding of the molding apparatus (3) is made of aluminum and comprises a movable male mold (4) and a fixed female mold (5). The female mold (5) has a first sprue (6 ) And the second sprue
A mixing head (8) is provided at the center where (7) meets,
Reactive raw material resin is injected from the mixing head (8) into the cavity (10) through the gate (9). A plurality of overflow grooves (11) are provided on the parting line of the female mold (5), and the air in the cavity (10) is filled in the box-shaped fiber-reinforced resin composite (A) which is a molded product. It is designed to be discharged outside so as not to get caught.

The mat-like material (14) or (15) is sandwiched between two mat-like reinforcing fibers (16) and laminated in a sandwich form. In this case, the box-like fiber-reinforced resin composite (A Use a high porosity mat for the thin side wall (1) forming part and a low porosity mat for the thick side wall (2) forming part. . Then, after the sandwich-like laminate is placed in the mold, the mold is closed, and the reactive raw resin is injected into the die from the gate (9), so that the raw resin infiltrates the resin flow space of the mat-shaped body. At the same time, the raw resin that has entered the resin circulation space is impregnated into the mat-like reinforcing fibers on both sides.

If both of the mat-like bodies disposed on the portion where the thin side wall (1) is formed and the portion where the thick side wall (2) is formed have the same porosity, the latter has lower flow resistance than the former. Therefore, the raw material resin flows preferentially to the latter, and reaches the tip of the latter prior to the former, and as a result, the thin side wall
Air is trapped in (1), and an unimpregnated portion of the raw material resin is generated, or a weld line is formed at a confluence of the raw material resin to impair the appearance.

In the present invention, however, the thin side wall (1)
The above problem does not occur because the raw material resin flows at substantially the same speed in the formation portion and the thick side wall (2) formation portion.

FIG. 3 shows a plate-like fiber-reinforced resin composite (B) having two different thicknesses, a thin portion (12) and a thick portion (13). In forming this plate-like fiber-reinforced resin composite (B), as shown in FIG. 4, two mat-like bodies (14) (1)
5) are arranged side by side, sandwiched between two mat-like reinforcing fibers (16), and laminated in a sandwich shape. In this case, the thin portion (12) of the plate-like fiber-reinforced resin composite (B) to be molded is formed. )
A mat-shaped body (14) having a high porosity is disposed in the formation portion, and a mat-shaped body (1) disposed in the formation portion of the thick portion (13) is formed.
For 5), one having a low porosity is used. When the box-shaped fiber-reinforced resin composite (A) or plate-shaped fiber-reinforced resin composite (B) is formed, a net may be used instead of the mat.

FIG. 5 shows a plate-like fiber-reinforced resin composite (C) having three different thicknesses, a thin portion (17), a medium portion (18), and a thick portion (19). In forming the plate-like fiber-reinforced resin composite (C), as shown in FIG. 6, in the portion where the thin portion (17) is formed, one net-like body (20) is divided into two mat-like reinforcing fibers ( 16), and in the formation part of the medium meat part (18), 2
The net-like body (21) and the three mat-like reinforcing fibers (16) are alternately arranged one by one so that the latter is on the outside. The reticulated body (22) and the four mat-like reinforcing fibers (16) are alternately stacked one by one such that the latter is the outermost layer. At this time, the net (20) arranged at the portion where the thin portion (17) is formed, the net (21) arranged at the portion where the middle portion (18) is formed, and the net arranged at the portion where the thick portion (19) is formed In order of the body (22), those having different meshes and having high porosity are used. When the plate-like fiber-reinforced resin composite (C) is formed, a mat-like body may be used instead of the net-like body.

[0021]

EXAMPLES Examples of the present invention will be described below together with comparative examples. Example 1 In molding the box-shaped fiber-reinforced resin composite (A) of FIG. 1 using the molding apparatus (3) of FIG.
The laminate formed by sandwiching the sheets between the mat-like reinforcing fibers and sandwiching them was placed in a mold heated to 70 ° C. with warm water.

As the mat-like reinforcing fiber, a glass continuous mat (M8609, manufactured by Asahi Fiberglass Co., Ltd.)
600 g / m ² ). As the mat-like body, a continuous mat made of polypropylene (hereinafter referred to as “PP mat”, which can be compressed with a wire diameter of 0.6 mm and a thickness of 10 mm) was used. In the portion where the thin side wall (1) (thickness 5 mm) is formed, a PP mat with a basis weight of 300 g / m ² (the porosity of the resin circulation space is 93%), and in the portion where the thick side wall (2) (thickness 8 mm) is formed Used a PP mat having a basis weight of 1200 g / m ² (the porosity of the resin circulation space was 83%). The glass content of the thin side wall (1) was 27% by weight, and the glass content of the thick side wall (2) was 20% by weight.

The mold is closed, and a gate (9) corresponding to a portion below the bottom of the box-shaped fiber-reinforced resin composite (A), which is a molded body, so that the specific urethane resin has a specific gravity of 0.6 using only the resin.
Shot from The resin used as the raw material component is a polyol (SBU polyol H52 manufactured by Sumitomo Bayer Urethane Co., Ltd.).
3) 100 parts by weight and 186 parts by weight of isocyanate (SBU Isocyanate 0389 manufactured by Sumitomo Bayer Urethane Co.), the former being the mixing head (8) from the first sprue (6) and the latter being the mixing head from the second sprue (7). (8), where both were mixed. Table 1 shows the results of a bending test performed on the thin side wall and the thick side wall of the obtained box-shaped fiber reinforced resin composite according to JIS K7055.

[0024]

[Table 1] The obtained box-shaped fiber-reinforced resin composite had no raw material resin-impregnated portion or weld line.

Example 2 A box-shaped fiber-reinforced resin composite was formed in the same manner as in Example 1 except for the following. For the thin side wall (1) forming portion, a plain mesh wire mesh with a mesh of 4 mesh and a wire diameter of 1.0 mm was used as a mesh,
Two layers of this are sandwiched between two mat-like reinforcing fibers and laminated. At the portion where the thick side wall (2) is formed, a 11-mesh mat, a 1.0-mm wire diameter, and a plain-woven wire mesh are used. ,
Three of these were laminated and sandwiched between two mat-like reinforcing fibers and laminated. The obtained box-shaped fiber-reinforced resin composite had no raw material resin-impregnated portion or weld line.

Comparative Example A box-shaped fiber-reinforced resin composite was formed in the same manner as in Example 1 except for the following. In the portion where the thin side wall (1) is formed, a PP mat having a thickness of 300 mm / m ² and a thickness of 5 mm is used as a mat-like body, and one of the mats is sandwiched between two mat-like reinforcing fibers and laminated. In the formation part, 50
A PP mat having a thickness of 0 g / m ² and a thickness of 8 mm was used, and one of the mats was sandwiched between two mat-like reinforcing fibers and laminated. The obtained box-shaped fiber-reinforced resin composite was a defective product in which a raw material resin-unimpregnated portion was present.

[0027]

According to the method for producing a fiber-reinforced resin composite of the present invention, it is possible to reduce the difference in the flow rate of the reactive raw material resin due to the difference in the thickness of the fiber-reinforced resin composite to be molded. Therefore, it is possible to obtain a good molded body without a raw resin unimpregnated portion or a weld line.

[Brief description of the drawings]

FIG. 1 is a perspective view of a box-shaped fiber reinforced resin composite having a thin side wall and a thick side wall.

FIG. 2 is a front view in which a part of a molding device is cut away.

FIG. 3 is a perspective view of a plate-like fiber-reinforced resin composite having a thin portion and a thick portion.

FIG. 4 is an exploded perspective view showing a state before lamination of a mat-like body and a mat-like reinforcing fiber for producing the plate-like fiber-reinforced resin composite of FIG.

FIG. 5 is a perspective view of a plate-like fiber reinforced resin composite having a thin part, a medium part, and a thick part.

FIG. 6 is an exploded perspective view showing a state before laminating a net-like body and a mat-like reinforcing fiber for producing the plate-like fiber-reinforced resin composite of FIG.

[Explanation of symbols]

 (1): Thin side wall (2): Thick side wall (12) (17): Thin part (13) (19): Thick part (14) (15): Matte body (16): Matte reinforcing fiber (18): Medium part (20)-(22): Reticulated body

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. After the mold is closed, the mold is closed and the reactive material resin is injected into the mold, so that the material resin is introduced into the mat-shaped or reticulated resin flow space or the mat-shaped reinforcing fiber and the mat-shaped or reticulated material. A method for producing a fiber-reinforced resin composite having different thickness portions for impregnating the raw resin infiltrated into the resin circulation space with the mat-like reinforcing fibers while infiltrating the resin circulation space formed by the body. A mat or a net having a high porosity is disposed in a portion where the thickness is formed thin, and a mat or a net having a low porosity is disposed in a portion where the thickness is formed relatively thick. Features to A method for producing a fiber-reinforced resin composite.