JPH0449027A - Manufacture of frp molded form - Google Patents

Abstract

PURPOSE:To prevent the positional displacement of a core material by setting a reinforcing material in a shape that a foamed core layer is held integrally between fiber layers to a resin injection molding die. CONSTITUTION:A laminate 1 composed of an upper fiber layer 2, an intermediate layer 3 and a lower fiber layer 4 is preheated by an open type preheater 11. Consequently, the intermediate layer 3 including a granular foaming resin is foamed and expanded, and a reinforcing material 12 in a shape that a foamed core layer 22 is held between the upper and lower fiber layers 2, 4 is obtained. A molded reinforcing material 14 is acquired by pressing the reinforcing material 12 by a molding die 13. The peripheral section of he reinforcing material 14 is trimmed and set to a resin injection molding die 16, and a two-pack type reactive liquid resin 17 is injected into the die 16 through a filler hole 19 from a mixing head 18. The liquid resin 17 injected is fluidized while being permeated into the fiber layers 2, 4 of the reinforcing material 14, the reinforcing material 14 is covered completely with the resin 17, and the liquid resin 17 is given heat by a heating mechanism set up to the resin injection molding die 16 and cured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing an FRP molded product using reinforcing fibers and a core material as reinforcing materials.

(Prior Art) As a reinforcing material for FRP (fiber reinforced plastics), chopped or matted reinforcing fibers are generally used as well known.

In addition, when making structural parts using FRP that require strength and rigidity in addition to being lightweight, a core material is often provided inside the PPP molded product, so as not to lose the advantage of FRP that it is lightweight. A lightweight foam material or honeycomb material is usually used as the core material. As shown in FIG.
The fiber base material 26 and the resin are integrated in the mold so that a fiber base material 7 is formed. On the other hand, honeycomb materials are usually made into a honeycomb core sandwich structure by applying adhesive 32 to both sides of a stretched core 31 and pasting FRP surface plates 33 together, as shown in FIG. Since honeycomb materials have poor formability and can only be used for plate-shaped products, the former foam material is exclusively used as a lightweight reinforcing material for manufacturing FRP molded products with complex shapes.

Many methods of manufacturing FRP molded products using reinforcing fibers and foam core materials are known, but such high-strength FRP molded products have the advantage of being able to integrally mold the fiber base material and foam core material. In most cases, FRP molded products are manufactured by resin injection molding with
After the fiber base material and foam core material are set in a mold, reactive liquid resin is injected into the mold through the injection hole provided in the mold and cured. (see publication).

(Problems to be Solved by the Invention) In the method of manufacturing an FRP molded product having a foamed core material by resin injection molding, it is necessary to separately manufacture the fiber base material and the foamed core material, and the mold cost and manufacturing cost for this is high. Since the cost is not small, there is a problem that FRP molded products cannot be provided at low cost. This problem is particularly noticeable in large, complex-shaped parts that require a large number of foam core materials.

In addition, there is a problem that the foam core material shifts when it is set in the mold, resulting in the production of FRP molded products with defects in quality.
In RP molded products, since the bonding strength between the foam core material and the FRP layer is low, delamination occurs when stress is applied to the molded product, which tends to cause a decrease in strength.

The present invention has been made for the purpose of solving the above-mentioned problems, and the problem to be solved is that in a method for manufacturing an FRP molded product that includes a foam core material in addition to a fiber base material as a reinforcing material, To provide a method for manufacturing a high-strength FRP molded product without the need to separately produce a foam core material and a foam core material, and without causing displacement of the core material during resin injection molding.

(Means for Solving the Problems) The method for producing an FRP molded product of the present invention involves molding a laminate consisting of an intermediate fiber layer containing a granular foamable resin and two fiber layers sandwiching it by a suction molding method. By preheating this laminate inside or outside the mold to foam the granular foamable resin, a reinforcing material having a foamed core layer sandwiched between two fiber layers is manufactured, and then the reinforcing material is molded. It is characterized by resin injection molding while it is set inside.

The suction molding method is a method of dispersing a material in a dispersion medium (liquid or gas) and suctioning the dispersion medium through a filter to obtain a molded body in which the material is deposited on a filter.In the present invention, water is added to the dispersion medium. The suction molding method using the fibers used to make the two fibrous layers and the intermediate fibrous layer containing the granular foamed resin may be the same or different, and may include glass fibers, carbon fibers, Kevlar fibers, etc. Any fiber can be used as long as it can strengthen the resin.

Examples of the granular foamable resin added to the intermediate fiber layer include granules obtained by adding a foaming agent, a curing agent, etc. to a reactive thermosetting resin such as a phenol resin, a urethane resin, or an epoxy resin. The particle size of the resin may be about 0.05 to 2+ am. As the blowing agent, chemical blowing agents that decompose and generate gas when heated, such as azonitrile compounds, benzenesulfohydrazine compounds, and diazoamide compounds, can be used.

Preheating to obtain a reinforcing material to be set in a mold from a suction-molded laminate is performed using preheating equipment such as an oven method, a far-infrared method, or a high-frequency method, which are commonly used for preheating resins. Just do it. In this case, the reinforcing material obtained must not be heated and cured to the extent that it becomes impossible to mold it.It depends on the type of granular foamable resin, but the preheating temperature is 1[11(] -150°C in the case of poly()). On the other hand, preheating to obtain reinforcing material from the laminate inside the mold is performed using mold heating means (heat medium liquid flow pipe, etc.) provided in the mold.In this case, the preheating temperature is the same as that outside the mold. It may be more expensive than preheating.

To shape the reinforcing material into a product, you can either press it with a resin injection mold, or mold it with a separate press mold.
The reinforcing material can be made by preheating in a mold, or the laminate with a specific shape can be preheated by using a filter with a specific shape in the suction molding device when making the laminate. The shape to be used may be selected depending on the difficulty of the shape.

An FRP molded product can be obtained by injecting a low-viscosity liquid resin or resin raw material into the mold with the reinforcing material set in a resin injection mold and curing it. In addition to manufacturing FRP molded products made of thermosetting resins such as resins, we also manufacture FRP molded products made of thermoplastic resins such as vinyl acetate resin, polyamide, polycarbonate, etc.
FiberReinforced Ther+mop
It can also be applied to the production of molded products.

(Function) When a laminate consisting of an intermediate fibrous layer containing a granular foamable resin and two fibrous layers sandwiching it is molded by suction molding, a laminate in which the fibers of adjacent layers are intertwined and integrated is obtained. It will be done. When this is preheated, the granular foamable resin contained in the intermediate fiber layer is melted and diffused between the fibers by heat, and a foam is formed by a foaming reaction, resulting in a foamed core layer that has been hardened to some extent. Manufacturing a reinforcing material with an integral structure in which the core material (intermediate foam core layer) is sandwiched between the fiber base materials (two fiber layers) in this way is different from the conventional method where the fiber base material and core material are sandwiched between the fiber base materials (two fiber layers). Eliminates the need to manufacture them separately.

The elasticity of the intermediate foam core layer enhances the shape followability of the reinforcing material (the ability to deform to follow the shape of the mold), and makes it easy to set the reinforcing material in the mold without any gaps. Note that foaming in a mold improves shape followability and workability. The foam core layer sandwiched between the two fiber layers is further foamed and hardened by the heat during resin injection molding. The expansion force prevents the reinforcing material from shifting due to resin injection pressure, and F
Fibers are uniformly filled into the RP matrix resin, the core material is embedded in a precise position, and an FRP molded product is produced in which the FRP layer and the foam core layer are integrated.

(Example) Hereinafter, an example of the method of the present invention will be described based on the drawings.

Example 1 In this example, a laminate 1 as shown in FIG.
Manufacture P molded products. This layered body 1 consists of three layers: an upper fiber layer 2, an intermediate layer 3, and a lower fiber layer 4. The upper fiber layer 2 and the lower fiber layer 4 are made of chopped glass fibers 5 which are commonly used in the fiber base material of FRP, and the middle layer 3 is made of granular foamable resin 7 and chopped glass fibers. The laminate 1 made of a mixture of 6 and 6 is manufactured by a suction molding apparatus as shown in FIG. This device consists of a tank 15 containing water 8.
In this device, a filter 10 is provided at the bottom of the filter 10, a stirring tank is provided above the filter 10, and water is sucked and drained from below the filter 10. The filter 10 is a filter that allows liquid to pass through but does not allow fibers or granular foamed resin to pass through.

First, water 8 to which a surfactant has been added and chopped glass fibers 5 are poured into the tank 15 from above, and after thoroughly mixing with the stirrer 9, the drain pipe 2 provided at the bottom of the tank 15
Through this filtration operation, chopped glass fibers 5 are deposited on the surface of the filter 10 to form a lower fiber layer 4. Next, water 8 to which a surfactant has been added is poured out. , chopped glass fibers 6 and granular foamable resin 7 are placed in a tank 15 and stirred, and then filtered in the same manner as before to form an intermediate layer 3 (made of a mixture of granular foamable resin 7 and chopped glass fibers 6) 1) is formed on the already formed lower fiber layer 4. Thereafter, the upper fiber layer 2 is formed on the intermediate layer 3 by repeating the first operation.

Upper fiber layer 2, intermediate layer 3 and lower fiber layer 4 thus obtained
The laminate 1 is preheated in an oven-type preheating device 11 as shown in FIG. ) A reinforcing material 12 is obtained in which a foam core layer 22 is sandwiched between upper and lower fiber layers 2.4.

By pressing it with a mold 13 as shown in FIG. 3 fdl, a molded reinforcing material 14 is obtained. After setting the reinforcing material 14 into a product shape by trimming its peripheral edge into a resin injection mold 16 as shown in FIG. Type 1
Inject into 6.

The injected liquid resin 17 is applied to the reinforcing material 14 [Fig. 3 (dl
After flowing while penetrating into the fiber layer 2.4 and completely covering the reinforcing material 14, it is heated by a heating mechanism (not shown) provided in the resin injection mold 16 and hardened. Meanwhile, the foam core layer 2 of the reinforcement material 14
The portions of No. 2 that have not yet been foamed and hardened are also foamed and hardened depending on the mold. After curing, the mold is demolded to obtain an FRP molded product 20 having an FRP layer 21 on the surface and a foam core layer 22 on the inside, as shown in FIG. 3 (f+).

Example 2 The laminate 1 shown in FIG. 3(a) is not preheated outside the mold, but is directly preheated in a resin injection mold. After changing the laminate 1 into a reinforcing material properly set in the mold 16, the same procedure as in Example 1 was carried out (the third
(See Figure (e) - ge)) 0 for manufacturing FRP molded product 20
Although this example requires a slightly longer preheating time for the shark than in Example 1, it is superior in terms of followability to mold shape and workability.

(Effects of the Invention) According to the method of the present invention, the reinforcing material in which the foam core layer is integrally sandwiched between the fiber layers is set in the resin injection mold, so the FRP molded product is free from misalignment of the core material. is obtained.

In addition, in the method of the present invention, the reinforcing material is set in the mold by crushing the elastic intermediate foam core layer or by using the foaming force, so that the shape followability of the reinforcing material is improved.
During molding, the foam core layer generates an expansion force that counters the injection pressure of the resin, eliminating the occurrence of resin-rich areas that occur in areas with small corner radii of the molded product.

Moreover, since the reinforcing material is used in which the fibers of the intermediate foam core layer are intertwined with two fiber layers, the FR of the resulting molded product is
The bonding strength between the P layer and the foam core layer is increased, and an FRP molded product with excellent peeling resistance and shear strength can be obtained.

Furthermore, it is no longer necessary to separately manufacture the fiber base material and the core material, and the work of setting the reinforcing material into the mold becomes simple, resulting in the effect of improving productivity.

[Brief explanation of drawings]

Fig. 1 is a cutaway perspective view of a laminate serving as a reinforcing material according to an embodiment of the method of the present invention, Fig. 2 is an explanatory diagram showing a method for manufacturing the laminate, and Fig. 3 is a subsequent FRP molding. Figure 4 is an explanatory diagram showing an example of the manufacturing method for FRPF and shaped products reinforced with a conventional core material. Figure 5 is a process diagram showing an example of the manufacturing method for FRPF molded products reinforced with a different core material. FIG. 3 is an exploded perspective view showing the structure. In the figure, l...laminate, 2... upper fiber layer, 3...
Intermediate layer, 4... Lower fiber layer, 5.6... Chopped glass fiber, 7... Granular foamable resin, 8... Water, lO...
Filter, 11... Preheating device 12... Reinforcing material, 14... Molded reinforcing material. 16...Resin injection mold, 17...
Liquid resin, 20...FRP molded product. Figure 1 Figure 2 Patent Applicant Toyota Motor Corporation Agent Patent Attorney Yumi Kaede (2 others) 4 Sojuoh 144

Claims (1)

[Claims] A laminate consisting of an intermediate fiber layer containing a granular foamable resin and two fibrous layers sandwiching it is molded by suction molding, and this laminate is preheated in or outside the mold to form the granular foamable resin. Manufacturing of an FRP molded product characterized by manufacturing a reinforcing material with a foamed core layer sandwiched between two fiber layers by foaming, and then resin injection molding with the reinforcing material set in a mold. Method.