JPH04286612A - Manufacture of fiber reinforced plastic molding with flange - Google Patents

Abstract

PURPOSE:To provide a method of molding a fiber reinforced plastic molding with a flange, which is suitable for molding efficiently a molding with large strength at low cost. CONSTITUTION:An air permeable cushion material 8 is put directly on a lower mold 4, or on fiber or a fiber composite material 9 previously mounted on the lower mold, so as to be situated from the mold matching part 5 of a mold comprising an upper mold 2 and the lower mold 4 to a cut-off part 6 and a flange part 7, and after further fiber or a fiber composite material 9 is mounted on the cushion material 8, mold clamping is effected until the cut-off part 6 between the upper mold 2 and the lower mold 4 comes into contact with the front and rear surface of the cushion material, and then resin is injected from an injection port, and after the injection of resin, molding is carried out by conducting perfect mold clamping.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a flanged fiber-reinforced plastic molded product, such as a bathtub.

0002

[Prior Art] When producing medium or small quantities of products made of fiber-reinforced plastic with thick flanges, such as bathtubs, SMC (sheet molding compound) is used.
Molding requires high pressure, making molds and presses expensive, which poses a problem in terms of profitability.Also, with resin injection molding, the mold is clamped close to the final state, and the resin is injected into a closed mold sealed with packing, so the resin The pressure is also high, which makes the mold expensive, and there is also the problem that the fiber content cannot be higher than 45%. On the other hand, there is a matched die molding method in which fibers are placed on a mold, resin is poured on top of the fibers, and the mold is then clamped. It is necessary to increase the viscosity, and therefore the fiber content is 35% or less, which reduces the strength of the molded product.

[0003] Conventionally, therefore, a molding method is known in which the cut-out portion of the mold is sealed with fibers (for example, Japanese Patent Laid-Open No. 63
(Refer to Publication No.-288723).

0004

[Problems to be Solved by the Invention] However, in the molding method that seals with fibers as described in the conventional technology, since the fibers themselves do not have cushioning properties, the pressing force changes due to slight variations in the embossing stroke, resulting in resin leakage. In addition, there is a small gap between the cavity and core mold space during resin discharge, which limits the reduction in discharge pressure, and further increases the thickness (strength) of the flange part of the molded product. In order to do this, there are many resin parts, which increases the molding time due to hardening. In addition, packing is required separately from the molded product, and especially when the sealing material is glass fiber, etc., wear and galling of the cut-out parts occur. There was a problem in that it was easy to clean and it was difficult to clean up the remaining fibers.

An object of the present invention is to provide a method for molding a flanged fiber-reinforced plastic molded product that is suitable for inexpensively and efficiently molding a high-strength molded product.

[0006]

[Means for Solving the Problems] The present invention provides an air-permeable cushioning material that is placed over the lower mold so as to be located from the mating part to the cutout part and the flange part of a mold consisting of an upper mold and a lower mold. After placing the fiber or fiber composite material directly on the cushion material or on the fiber or fiber composite material that has been placed on the lower mold in advance, the cut-out parts of the upper mold and the lower mold are This is a molding method in which the mold is clamped until the front and back of the cushioning material are in contact with each other, resin is injected from the injection port, and after the resin is injected, the mold is completely clamped and molded.

[0007] As the breathable cushioning material used in the molding method of the present invention, polyethylene, polystyrene, phenolic resin or rubber foam is preferred. In addition, in order to prevent wear and galling of the cut-out portions of the mold, it is recommended that the fibers or fiber composite material be placed on the inner side of the cut-out portions of the upper and lower molds. preferable.

[0008] In the present invention, the state where the molds are clamped to the point where the cut-out portions of the upper and lower molds are in contact with the front and back sides of the cushion material means that the upper and lower molds are brought close together and the cut-out portions of the upper and lower molds press the cushion material. This is a condition in which the resin is prevented from flowing out. The mold consisting of an upper mold and a lower mold used in the present invention has a cutting part clearance of 0.05 to
A material made of metal, FRP, or the like with a slide length of about 4 to 20 mm is used. Further, as the fiber or fiber composite material used in the present invention, various fibers or fiber composite materials such as glass fiber, carbon fiber, polyamide fiber, polyester fiber, and ceramic fiber are used, and the resin to be injected is polyester, polyester amide, etc. Thermosetting resins such as , epoxy, urethane, and phenol are preferred, and can be used at low viscosity of 1500 cps or less. The temperature of the mold is heated to 100-200℃, and the pressure applied by the mold is 10-50 kg/cm2. Molding is completed in about 30 seconds to 20 minutes, depending on the thickness, resin, and composition of the molded product. do. The breathable cushioning material may be formed by discharging foaming liquid directly into the mold instead of installing a separate pre-molded item, or by foaming the cushioning material outside the mold or using an adhesive or the like. After being integrated with fibers or fiber composite material, it may be placed in a mold. Furthermore, as shown in FIGS. 1 to 3 of the embodiment, the cushioning material is placed on the support plate 12 of the support member consisting of the support plate 12, springs 13, etc. provided on the lower mold 4, and the upper and lower molds are brought close to each other. After fixing the cushioning material so that it does not move and preventing the resin from flowing out by appropriately pressing it with the cut portion 6, the resin is injected from the injection port.

[0009]

[Examples] The contents of the present invention will be explained below with reference to Examples.

Example 1 The molded product had a thickness of 6 mm at the flange part and a thickness of 3 mm at the other parts.
mm, length 400mm, width 300mm, height 100mm
Figure 4 shows a schematic diagram of the molding press and mold, and Figure 2
Figure 2 shows the cutting part when the mold is completely closed. In Fig. 4, 1 is the press plate surface, 2 is the upper mold, 3 is the injection port, and 4 is the lower mold. It is 7mm. The resin is polyesteramide resin,
Glass fiber was used as the fiber 9, hard urethane foam was used as the cushioning material, a RIM injection machine was used as the molding machine, and a downward press type hydraulic press was used as the press, and molding was performed using the above test mold. In FIG. 1, 10 layers of a continuous strand preform mat of 350 kg/m2 as fibers or fiber composite material 9 are placed on a lower mold 4 heated to 180° C. at a cutout portion 6.
Set it up close and press it into the middle layer so that it extends from the flange part 7 to the cutting part 6 and the mold matching part 5.
Set the cushioning material 8, which is a hard urethane foam made of 5x foam, with a width of 40 mm, which is breathable and has a thickness of 8 mm in some parts and 3 mm in other parts. Stop the descent, prevent the cushioning material 8 from moving at the cutting part 6, and seal the liquid at 150°C.
A liquid (resin, etc.) and B liquid (curing agent, etc.) heated to 20℃
is discharged into a mold at a rate of 20 kg/cm2 while mixing at the outlet at a ratio of 8:2 with a viscosity of 30 cps. Thereafter, the mold was completely clamped, and molded by applying pressure and heating at 25 kg/cm2 for 2 minutes. The results of the obtained products are shown in Table 1.
, glass content 70%, tensile strength 30kg/mm
2. A molded product with a bending strength of 50 kg/mm2 was obtained.

Example 2 Instead of the cushioning material 8 made of hard urethane foam in Example 1, a cushioning material 8 made of breathable hard phenol with 5x foaming was used. The results of the obtained product were similar to those of Example 1, as shown in Table 1.

Comparative Example 1 The same product as in Example was molded by a conventional resin injection method. Table 1 shows the results of the obtained products.

Comparative Example 2 The same product as in Example was molded using the molding method described in the prior art in which the cutout portion was sealed with glass fiber. Table 1 shows the results of the obtained products.

[0014]

[Table 1]

[0015]

According to the present invention, air escapes through the breathable cushioning material and the resin is injected into a large space inside the mold, making it possible to inject even lower viscosity resin at a lower pressure. Since it is used, it has elasticity and the seal at the cutting part is more reliable. Furthermore, since the core material of the flange part of the molded product is fiber or fiber composite material and cushioning material, less resin is required despite the thick wall, making the molded product inexpensive, quick to cure, and having a strong flange. is obtained. Furthermore, since a low-viscosity resin can be used, it is possible to have a high fiber content with good fluidity and impregnation properties, and it is also possible to create a fast-curing formulation, and because of the low pressure, press molds and molds are inexpensive. It is also possible to create a vacuum in the mold and raise the temperature of the resin using a slide seal device and vacuum pump before injecting the resin, allowing for even shorter molding times. There is also the advantage of being able to obtain products.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a cushioning material pressed by a cutting part of a mold, showing an embodiment of a molding method according to the present invention.

FIG. 2 is a cross-sectional view showing the state of the cutting part when the mold is completely closed from the state of FIG. 1;

FIG. 3 is a cross-sectional view showing an example different from FIG. 1, in which fibers or fiber composite materials are set and molded only on the upper side of the cushion material.

FIG. 4 is a schematic cross-sectional view showing a molding press/mold used in Examples.

[Explanation of symbols]

1...Press board surface
2... Upper mold (cavity) 3... Inlet
4...Lower mold (core) 5...Mold matching part
6... Cutting part 7... Flange part
8... Cushion material 9... Fiber or fiber composite material
10...Gap 11...Mold space
12...Support plate 13...Spring

Claims (3)

[Claims] Claim 1: A cushioning material having air permeability is placed directly on the lower mold or on the lower mold so as to be located from the mating part to the cutting part and the flange of a mold consisting of an upper mold and a lower mold. After placing the fiber or fiber composite material on the cushion material that has been placed in advance, and placing the fiber or fiber composite material on top of the cushion material, the cutting parts of the upper mold and the lower mold come into contact with the front and back sides of the cushion material. A method for molding a fiber-reinforced plastic molded article with flanges, characterized in that the molds are closed until they touch each other, resin is injected through an injection port, and after the resin is injected, the mold is completely closed and molded. 2. The method for molding a flanged fiber-reinforced plastic molded article according to claim 1, wherein the breathable cushioning material is a foam of polyethylene, polystyrene, phenol resin, or rubber. 3. The method for molding a flanged fiber-reinforced plastic molded product according to claim 1 or 2, wherein the fiber or fiber composite material is placed inside the cutout portions of the upper mold and the lower mold.