JPH0622914B2 - Manufacturing method of fiber reinforced plastic products - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a fiber-reinforced plastic product useful for a tennis racket, a shaft pipe-shaped structure of a golf club, or the like.

(Prior Art and Problems Thereof) A fiber-reinforced plastic product is formed by placing reinforcing fibers such as glass fibers in a mold and injecting a rim molding monomer.

However, in the case of this rim molding, since the reinforcing fibers are densely arranged in order to increase the strength, there are places where the resin does not penetrate due to the rim molding. In particular, the resin hardly penetrates into the part where the reinforcing fiber is in close contact with the wall surface of the mold, resulting in a poor appearance.

In order to avoid such a poor appearance, it is conceivable to provide a thermoplastic resin layer (gel coat layer) on the surface of the rim molded product, but the manufacturing process of the product becomes complicated and the cost increases. Therefore, usually, the molded product is buffed and putty is applied for repair. However, this repair also takes a long time and is not always an excellent method.

(Means for Solving Problems) The inventors of the present invention have studied the manufacturing method of the fiber reinforced plastic product that suppresses the defective appearance without using complicated steps such as gel coat layer and putty coating, and the present invention has been achieved. Came to.

That is, the present invention is characterized in that a nonwoven fabric layer having a fiber density of 2 to 35 Vol% is provided between the reinforcing fiber and the mold in the method for producing a fiber-reinforced plastic product in which the reinforcing fiber is arranged in the mold and rim-molded. Provide a manufacturing method for fiber reinforced plastic products.

Rim molding means reaction injection molding, and is a method in which reactive monomers are mutually introduced into a mold, and the reaction is carried out at room temperature or at elevated temperature to carry out molding. The resin obtained by rim molding may be any conventional one such as polyurethane or polyamide. Suitable rim-forming monomers for the present invention include UBE nylon (UX-21) commercially available from Ube Industries.

The reinforcing fibers to be placed in the mold in advance may be any of those usually used for fiber reinforced plastics. Typical examples of the reinforcing fiber are aramid fiber, carbon fiber,
Glass fiber etc. are mentioned. The most preferred reinforcing fiber is carbon fiber. The fibers may be in any form and may or may not be braided. It is preferably braided. According to the invention, a nonwoven layer is provided between the mold and the reinforcing fibers. Nonwoven fabrics that can be used are glass fiber paper,
Examples include carbon fiber paper, polyester non-woven fabric, and nylon non-woven fabric. This non-woven fabric has a fiber density of 2-35% by volume, and preferably 5-
A content of 20 Vol% is preferably used.

If the fiber density is higher than 35 Vol%, the resin will not easily penetrate and the appearance will be poor. On the other hand, if it is less than 2 Vol%, the non-woven fabric itself becomes too sparse, and even if a non-woven fabric layer is provided as the outermost layer of the carbon fiber blend layer, there may be places where the lower braid layer directly adheres to the mold wall surface, or the non-woven fabric layer. The resistance when the rim liquid flows becomes extremely small, and the rim liquid preferentially penetrates into the non-woven fabric layer and becomes less likely to permeate into the carbon fiber blend layer than the carbon fiber braid layer having a large flow resistance. Woven cloth may be used as long as the fiber density is within this range.

The manufacturing method of the present invention provides a non-woven fabric layer to improve the appearance of the fiber reinforced plastic product, and the manufacturing method of the product itself may be a conventional method. For example, in order to achieve the weight reduction of the fiber reinforced plastic product, it is preferable to provide the product with a hollow or foamed core. The most preferable embodiment is a method in which a tube is covered with a reinforcing fiber, the outer side of which is wrapped with a non-woven fabric is placed in a mold, and a foaming agent is injected into this tube and then foamed to conform to the shape of the mold. . The tube may be tough and flexible and can be obtained from nylon, cellophane, rubber, polyester, polyetheretherketone, or the like. In the present specification, the term "foaming agent" means an agent that foams and hardens under foaming conditions, and is usually a liquid or solid resin mixed with a foaming substance. Examples of suitable foaming agents include DIC RP commercially available from Dainippon Ink and Chemicals, Inc.
A mixture of 1147H and DIC SP299 can be mentioned.

(Effect of the Invention) When the nonwoven fabric layer is provided as in the present invention, the reactive monomer for rim molding easily penetrates, and molding defects and appearance defects such that only the reinforcing fibers are exposed on the surface hardly occur. The rim molded article obtained by the method of the present invention is greatly improved in its dyeability, and a molded product having a beautiful appearance can be obtained by dyeing.

(Examples) The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Example 1 Two layers of carbon fiber braid (fiber density: about 50 Vol%) manufactured by Toho Rayon Co., Ltd. were coated on the foam, and the outermost layer thereof was fiber paper (manufactured by Nippon Sheet Glass Co., Ltd. (UL4A ・ 30)).
Table 1 shows the surface finish of the racket frame-shaped rim molded product obtained by spirally winding a 30 mm width tape (fiber density: 11 Vol%) and only two layers of carbon fiber blend. The rim molding monomer used was UBE nylon (UX-21) manufactured by Ube Industries,
Solution A and solution B were used at a ratio of 1: 1. Set the above structure in a mold and add 1.5 kg / c of the above monomer under vacuum at 150 ° C.
Injection molding was performed at a pressure of m ² .

By using the glass fiber paper, the resin uniformly flows into the surface-reinforced fiber layer and the resin penetration insufficient portion is improved. If there is a non-woven fabric layer, it is not necessary to apply putty for repair,
As shown in Table-1, the time required for the buff and putty coating process was greatly reduced.

Example 2 The sample of Example 1 was buffed with # 360 sandpaper, Was used for 20 minutes at 90 ° C. Next, a urethane-based clear was applied, and as a result, it was dyed uniformly and had a transparent feeling and a very beautiful color.

Example 3 In the same manner as in Example 2, the staining was changed to Lanyl Blue 3G for staining. Current racket (epoxy matrix CFR
In P), the basic tone is black, and to put it in another color, it is necessary to undercoat white putty. Dyeing is not possible due to the epoxy resin used in the matrix. However, since the racket prototyped according to the present invention uses the non-woven fabric, it can be dyed uniformly and enables a dyed racket. This dyeing racket
When the base is glass fiber, it becomes the color of the matrix resin,
The color is free.

Also, when the base is carbon fiber, it becomes a blackish various color and it is a racket with transparency, deep color and gloss.

When non-woven fabric was not used, the color became Madara.

Example 4 Two layers of carbon fiber blends knitted so as to form an angle of 35 ° in the axial direction were laminated around a SUS mandrel. The surface finish of the rim molded pipe when the 40 mm width tape of the glass fiber paper of Example 1 was spirally wound on the outermost layer of this carbon fiber braid and when the carbon fiber braid was only two layers was the same as in Example 1. It was a result.

Example 5 Carbon fiber cloth (manufactured by Toho Rayon Co., Ltd.) W-3
No. 101 was cut into 150 × 150 mm, 18 layers were overlapped, and 150 × 150 mm used in Example 1 on both surfaces of the outermost layer.
The glass fiber paper (1) was placed in a laminated mold and rim-molded to form a plate having a thickness of 4 mm. Comparing the surface finishes of this plate and a plate formed only with carbon fiber cloth, the plate without the non-woven fabric layer was defective, and the plate with the non-woven fabric layer was good.

Next, the fiber density of the non-woven fabric layer is 2 Vol% or less and 35 Vol%
A comparative example molded as described above will be shown.

Comparative Example 1 A carbon fiber blade was laminated in an amount corresponding to a fiber density of 50 Vol%, and a glass fiber paper (nonwoven fabric) fiber density 1 was used as the outermost layer.
The plates were formed by stacking the layers corresponding to Vol% and placing them in a mold and injecting RIM nylon.

When this outermost layer was observed, the exposure of the carbon fiber to the surface layer was conspicuous, and there were an average of 3 resin-unimpregnated portions of about 1 mm ² per cm ^{2 on} the surface.

When the cross section was observed with an optical microscope, a portion not impregnated into the carbon fiber layer was conspicuous in the vicinity of the surface layer.

As shown in Table 2, the bending properties of this molded product were about 11% lower in strength and 7% lower in elastic modulus than the molded product having a nonwoven fabric fiber density of 5 Vol%.

Comparative Example 2 As in Comparative Example 1, the glass non-woven fiber density was 0.7 Vol.
% Board was molded.

When this outermost layer was observed, the exposure of the carbon fiber to the surface layer was more conspicuous than in Comparative Example 1, and about 3 mm ³ per 1 cm ^{2 of} surface was observed.
There were 4 resin-unimpregnated parts on average.

When the cross section was observed with an optical microscope, the portion not impregnated into the carbon fiber layer was more conspicuous in the vicinity of the surface layer than in Comparative Example 1.

As shown in Table 2, the bending properties of this molded product were about 18% lower in strength and about 10% lower in elastic modulus than the molded product having a nonwoven fabric fiber density of 2 Vol%.

Comparative Example 3 Carbon fiber blade W-3101 was used to obtain a fiber density of 50 Vol.
%, A glass fiber paper (nonwoven fabric) was laminated on the outermost layer by a fiber density of 40 Vol%, placed in a mold and injected with RIM nylon to form a plate.

When this surface layer was observed, there were an average of 3 resin-impregnated portions of about 3 mm ³ size per 1 cm ^{2 of} the surface.

When the cross section was observed with an optical microscope, voids were noticeable in the non-woven fabric layer and the carbon fiber blade layer.

As shown in Table 3, the bending properties of this molded product are about 23% lower in strength and 14% lower in elastic modulus than those of the molded product having a nonwoven fabric fiber density of 35 Vol%.

Example 6 A carbon fiber blade was laminated in an amount corresponding to a fiber density of 50% by volume, and a glass fiber paper was laminated in an outermost layer in an amount corresponding to a fiber density of 5% by volume, placed in a mold and injected with RIM nylon to form a plate.

The surface of the molded product is smooth and almost no void is observed on the cross section.

Table 4 shows the bending property values of the molded product.

Example 7 Carbon fiber blades were laminated by an amount corresponding to a fiber density of 50 Vol%, and a glass fiber paper was used as the outermost layer with a fiber density of 25 Vol%.
A considerable amount of layers were laminated, placed in a mold, and RIM nylon was injected to form a plate.

The surface of the molded product is smooth and almost no void is observed on the cross section.

The bending property values of the molded product are shown in Table-5.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroomi Matsushita 2-3-12-104, Minamikonaka, Suminoe-ku, Osaka City, Osaka Prefecture (72) Inventor Kunio Niwa 1-1-23, Hinoguchi-cho, Nishinomiya-shi, Hyogo Sumitomo Gom Kobu Dormitory, Kogyo Co., Ltd. (56) Reference JP 61-21876 (JP, A) JP 60-18322 (JP, A) JP 57-51416 (JP, A)

Claims (4)

[Claims] 1. A method for producing a fiber-reinforced plastic product in which reinforcing fibers are arranged in a mold to form a rim, wherein a nonwoven fabric layer having a fiber density of 2 to 35% by volume is provided between the reinforcing fibers and the mold. Manufacturing method of fiber reinforced plastic products. 2. The method according to claim 1, wherein the reinforcing fibers are glass fibers or carbon fibers. 3. The method according to claim 1, wherein the non-woven fabric is formed of glass fiber or carbon fiber. 4. The method according to claim 1, wherein the obtained fiber-reinforced plastic product is further dyed.