JPS60244510A - Preparation of plastic molded product - Google Patents

Abstract

PURPOSE:To prepare a plastic molded product having a uniform thin wall thickness, by laminating an uncured fiber reinforced plastic to a light foam member and setting the formed laminate to a silicon rubber pressing part having a diameter smaller than that of a laminate ring at ambient temp. before heating the same under pressure. CONSTITUTION:A core metal 12 is held to the recessed parts of upper and lower molds 6 so as to leave hollow part and room temp. curing type silicon rubber 10 is injected in the molds 6 from the injection port 14 provided to one of the molds 6 and cured at room temp. Next, the cured silicone rubber 10 is notched to take out the core metal 12 and the demolded silicone rubber 10 is inlaid with the core metal 12. The press curing of a laminated fiber reinforced plastic 4 is performed by pressing the molds 6 by a heating press part 11 under heating. By using a closed-cell foam such as a cured urethane foam as a foam member 3, defoaming and a thickness are uniformized.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing a plastic molded product in which a fiber-hardened plastic is laminated and cured on the outer surface of a lightweight foam member, and particularly to a lightweight steering wheel made of fiber-reinforced plastic. This invention relates to a method for manufacturing plastic molded products suitable for rims, etc.

[Prior art]

Figure 1 is a front view of the lightweight steering wheel.

Figure 2 is a sectional view taken along line A-A, and in the figure, (1)
is the rim part, (2) is the spoke part, (3) is the rim part (1)
(4) is a ring-shaped lightweight foam member made of a hard urethane foam material as a shape-retaining member, and (4) is reinforced with fibers such as glass fiber or carbon fiber laminated around the outer periphery of the lightweight foam member (3). It is a fiber-reinforced plastic with a matrix of thermosetting resin such as epoxy resin, and serves as a strength member for the rim (). (5) is the outer layer mold part. The above-mentioned lightweight steering wheel has a conventional steering wheel in which the core metal part of the rim part (1) and the spoke part (2) are made of metal such as iron, which has a low natural frequency and is easy to operate at high speeds. Therefore, in order to improve operability, the rim part is made lighter and has a higher natural frequency without reducing rigidity. (1) is lighter.

Next, a method for manufacturing the rim portion (1) will be explained.

The ring-shaped lightweight foam member (3) is formed by injecting rigid urethane foam into a mold from a foaming machine, and then applying epoxy resin to reinforcing fibers such as glass fiber or carbon fiber on the outer surface of the lightweight foam member (3). Thermosetting resins such as polyester resin and polyester resin are laminated in a wet state, defoamed, and placed in a mold to make the entire outer surface uniform in thickness.Then, the resin is cured under pressure and heat to form a thin film. And a strong fiber reinforced plastic (4) is molded. Fiber-reinforced plastic (4) is not laminated in a wet state, but by pre-impregnating reinforcing fibers with resin, semi-hardened prepreg tape is laminated onto lightweight foam member (3) using a winding method, etc., and then placed in a mold. In some cases, it is hardened by applying pressure and heating.

The outermost molded part (5) is made of rubber, vinyl chloride resin, or the like by low-pressure or high-pressure casting.

In the conventional manufacturing method, fiber reinforced plastic (4
), due to the low compressive strength of the lightweight foam member (3), sufficient pressure could not be applied to the metal mold surface, resulting in many air bubbles in the laminated fiber reinforced plastic (4). 1 remaining
The disadvantage was that the strength was significantly reduced. In addition, if you try to increase the shape of the lightweight foam member (3) and apply pressure, only the upper and lower parts that are in contact with the mold will be pressurized, deforming the lightweight foam member (3), and the shape of the product will be deformed after molding. Or, the lightweight foam member (3) is damaged, and the damaged part remains inside the ring body of the fiber-reinforced plastic (4), which has hardened and become stronger after molding, causing abnormal noise when vibrating. There were drawbacks. Furthermore, there is a drawback that the fiber-reinforced plastic (4) protrudes from the mating part of the mold, and when this protruding part is cut to form a ring shape, the reinforcing fibers are cut, resulting in a significant decrease in strength.

The drawback was that product functionality was lost.

[Summary of the invention]

This invention was made for the purpose of eliminating the above-mentioned drawbacks of the conventional method, and includes a method of heating and curing a laminate in which a fiber-reinforced thermosetting plastic is laminated on the outer surface of a lightweight foam member in a mold. A pressurizing part formed of silicone rubber is provided in the mold so as to have a recess with a size smaller than the size of the laminate, and the laminate is inserted into the recess and heated.
Provides a method for manufacturing plastic molded products that can uniformly pressurize and harden fiber-reinforced thermosetting plastic by utilizing the difference in volumetric expansion between the mold and silicone rubber when heated by applying pressure and hardening. It is something to do.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Third
The figure is a plan view of a mold according to an embodiment of the present invention, FIG. 4 is a sectional view taken along line B-B, FIG. 5 is a sectional view of the mold showing the molding state of the pressurizing part, and FIG. FIG. 2 is a cross-sectional view of the mold showing how parts are attached; in the figure, the same reference numerals as in FIGS. 1 and 2 indicate the same or corresponding parts. (6) is a mold made of a material with a small thermal expansion coefficient, such as steel, for pressure-curing the fiber-reinforced plastic (4) in a wet or prepreg state laminated on the outer surface of the lightweight foam member (3); 7) is the mating surface (8) of the upper and lower molds (6) so as to uniformly contact the entire outer surface of the fiber reinforced plastic (4).
) The ring-shaped recess (9) provided on the
10), and (11) is a heating press section that presses and heats the upper and lower molds (6) to suppress the floating of the molds due to the expansion force of silicone rubber (RTV) (10) when heated. be. (12) is attached to the mold (6) by the holding pin (13).
It is a fiber-reinforced plastic core held in the center of the recess (9) and whose cross section is laminated to the rim (1).

First, the pressure part (
7) is formed by holding the core bar (12) hollow in the four parts (9) of the upper and lower molds (6) with the holding pins (13), and then inserting it into the mold (6). Pour room temperature curing type silicone rubber (RTV) (10) through the injection port (14) provided, and place the silicone rubber (RTV) parallel to the mating surface (8) of the mold (6).
RTV) (10) with a cutter knife or the like to take out the core metal (12), and remove the recess (6) from the demolded mold (6).
9) Apply adhesive and remove the mold from silicone rubber (RT
V) (10) is fitted and firmly adhered to form upper and lower pressure parts (7) as shown in FIG.

Fiber-reinforced plastic (4) laminated to the rim (1)
The above mold (6) is used for pressure curing of silicone rubber A.
(RT V) (10) Te molded mold (6 parts (9)
When the upper and lower pressurizing parts (7) are opened and the ring-shaped lightweight foam member (3) is laminated with the fiber-reinforced plastic (4), even if the mold (6) is closed, the upper and lower molds will not close. (6)
The fiber reinforced plastic does not protrude between the mating surfaces (8). Next, place the upper and lower molds (6) into the heated press section (
11) Press and heat. The mold (6) is made of a material with a low coefficient of thermal expansion (for example, in the case of steel, αM-1,1x lo
−””c), so the curing temperature is t=100
Even if the temperature reaches ~180°C, the cavity VMT of the recess (9) of the mold (6) will be VMr = (1 + 3 cBt), assuming the cavity VMO at room temperature, and the temperature rise will be 120°C.
Even in °C, VMr=1,0036Vi+o, 0
．． This is only a 36% increase in the cavity. On the other hand, silicone rubber (RTV) (10) has a coefficient of thermal expansion αR = 1.8 ~
The increase in the capacity of the pressurizing part (7) is as high as 2.7 x 10-'/°C, assuming the capacity at room temperature as VRO, (ER = 2.7
10-'/℃, the capacity VRT during free expansion is V
RT=1.097VRO, the capacity increased by 9.7%, and the capacity increase rate was larger than that of the mold (6), and the pressure part (7) was placed in the recess (9) of the mold (6). This creates a pressurizing force on the uncured ring-shaped fiber-reinforced plastic (4), and makes the cross-sectional thickness of the pressurizing part (7) uniform, so that the entire circumference is covered with the metal of the mold (6). By shielding, uniform pressure is applied to fiber-reinforced plastics (4)
It can be given all over. The pressing force can be freely set by changing the dimension d2 of the core metal (12), and the pressing force can be set to be less than the compressive strength of the lightweight foam member (3) during heating. On the other hand, by using a closed-cell foam such as cured urethane foam for the lightweight foam member (3), it expands and pressurizes from inside the fiber-reinforced plastic (4) when heated, eliminating any air bubbles remaining inside during wet molding. It is possible to degas the air bubbles between the prepreg layers through the mating surface (8) of the mold (6) and mold a strong ring-shaped fiber-reinforced plastic (4) with uniform thickness and completely defoamed. can.

In addition, in the above example, a ring-shaped molded product with a round cross section was explained, but the cross section may be rectangular, and it is also possible to manufacture a frame-shaped product instead of a ring shape. It has the same effect as. In addition to rigid urethane foam, lightweight foam members include closed-cell polyethylene, polypropylene, polystyrene,
A vinyl chloride resin, a urea resin, or a shirasu balloon may be used, and the same effects as those described above can be achieved.

As described above, according to the present invention, the laminate is set in the pressurizing part of silicone rubber having a lightweight foam member diameter, and is cured by heating and pressure. By eliminating jamming and making the thickness of the pressurizing part uniform, pressure can be applied uniformly to the entire outer surface of the uncured ring body during heating, and the pressurizing force can be set arbitrarily by changing the cross-sectional diameter of the pressurizing part. When heated, the lightweight foam member applies expansion pressure from inside the fiber-reinforced plastic to defoam the bubbles, making it possible to mold a plastic molded product made of a strong, lightweight laminate with a thin, uniform thickness, and making molds. It also has the advantage of being simple and inexpensive.

[Brief explanation of drawings]

FIG. 1 is a front view of a lightweight steering wheel, FIG. 2 is a sectional view taken along line A-A in FIG. 1, FIG. 3 is a plan view of a mold in an embodiment of the present invention, and FIG. FIG. 5 is a sectional view of the mold showing the molding state of the pressurizing part, and FIG.
The figure is a sectional view of the mold showing the mounting state of the pressurizing part. In each figure, the same reference numerals indicate the same or corresponding parts]) is the rim part, (2) is the spoke part, (3) is the lightweight foam member,
(4) is fiber reinforced plastic, (5) is the outer mold part, (6) is the mold, (7) is the pressurizing part, (8) is the mating surface of the mold, (9) is the recess, (10) is silicone rubber (11)
(12) is a core metal, (13) is a holding pin, (14) is an injection port, and (15) is a pressurizing part recess. Agent Masuo Oiwa Figure 1 Figure 3 Figure 4 Figure 5 n Figure 6 Procedural amendment 1. Indication of the case: Japanese Patent Application No. 59-99996 2, Title of the invention: Method for manufacturing plastic molded products 3, Representative of the person making the amendment: Hitoshi Katayama Part 5, Date of amendment order: Voluntary amendment 7, Contents of the amendment (1) ) Amend the claims as shown in the attached sheet. (2) In the specification, page 5, line 12, and page 7, line 1, "bottom" is corrected to "top". (3) On page 10, line 10, correct "small" to "large". 2. Claims (1) A method of heating and curing a laminate in which a fiber-reinforced thermosetting plastic is laminated on the outer surface of a lightweight foam member in a mold, the method comprising: A pressurizing part molded from silicone rubber is installed in the mold.
A method for producing a plastic molded product, comprising inserting the laminate into the four parts and curing it by heating and pressurizing it. (2) The plastic molded product according to claim 1, wherein the lightweight foam member is a rigid urethane foam having closed cells, polyethylene, polypropylene, polystyrene, vinyl chloride resin, urea resin, or shirasu balloon. manufacturing method. (3) The plastic molded product according to claim 1 or 2, wherein the m-fiber reinforced thermosetting plastic is reinforced with glass fiber or carbon fiber and has an epoxy resin as a matrix. Production method. (4) The method for producing a plastic molded article according to any one of claims 1 to 3, wherein the silicone rubber is a silicone rubber that cures at room temperature.

Claims (4)

[Claims] (1) In a method in which a laminate in which a fiber-reinforced thermosetting plastic is laminated on the outer surface of a lightweight foam member is heated and cured in a mold, the laminate is molded from silicone rubber so as to have a concave portion having a size equal to or smaller than that of the laminate. A pressurizing part is provided in the mold,
A method for manufacturing a plastic molded product, comprising inserting the laminate into the recess and curing it by heating and pressurizing it. (2) The plastic molded product according to claim 1, wherein the lightweight foam member is a rigid urethane foam having closed cells, polyethylene, polypropylene, polystyrene, vinyl chloride resin, urea resin, or shirasu balloon. manufacturing method. (3) The plastic molded article according to claim 1 or 2, characterized in that the ll1t fiber-reinforced thermosetting plastic is reinforced with glass fiber or carbon fiber and has an epoxy resin as a matrix. Production method. (4) The method for producing a plastic molded article according to any one of claims 1 to 3, wherein the silicone rubber is a silicone rubber that cures at room temperature.