JPH0515366B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to fiber reinforced thermosetting resin (hereinafter referred to as FRP).
This invention relates to a molding method that allows continuous and efficient production of plates, particularly long plates.

[Conventional technology and problems]

Conventionally, known methods for forming FRP include a mated metal die method, a vacuum bag method, an autoclave method, and a filament winding method.

These molding methods are suitable for molding three-dimensional shapes with curvature or different thicknesses, but
Since it is a batch type, productivity is low and there are restrictions on the length of the laminate.

Pultrusion is a known method for continuous molding, but when pultruding a plate-shaped molded product, the mold must be changed each time the thickness of the molded product changes, resulting in a lack of flexibility. .

Furthermore, when the reinforcing fiber structure is a woven fabric, meandering of the reinforcing fibers is likely to occur when the fibers intersect with the drawing direction, and the mechanical properties of the obtained molded product are deteriorated.

[Purpose of the invention]

In order to solve the drawbacks of the prior art, the present invention has the following features:
To provide a method for forming FRP plates that does not require separate molds even when the thickness of the formed plate changes continuously.

[Structure of the invention]

In the present invention, a fiber reinforced material sheet and a thermosetting resin are sandwiched between mold release materials and continuously supplied between a heating plate and a pressure heating roller, and a curing reaction of the thermosetting resin is performed under pressure. This is a continuous molding method for a fiber-reinforced thermosetting resin molded plate, which is characterized by conveying the molded sheet while adjusting the molded sheet.

In the present invention, the fiber reinforced material sheet is a unidirectionally oriented sheet such as carbon fiber, glass fiber, or aramid fiber, woven fabric, or nonwoven fabric.

Thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, polyimide resins, and the like.

The fiber reinforcing material sheet and the thermosetting resin may be made into a prepreg sheet in advance, or the thermosetting resin film and the fiber reinforcing material sheet may be simultaneously supplied and impregnated and molded.

As the release material, normal release paper, metal film, etc. used for prepreg etc. can be used.

The method of the present invention will be explained with reference to the drawings.

FIG. 1 is a conceptual diagram showing one example of the steps of the method of the present invention.

In FIG. 1, 1 is a prepreg sheet in which a fiber reinforced sheet is impregnated with a thermosetting resin.
A mold release material (3) is placed on both sides of this prepreg sheet, and is supplied between the pressure and heat rollers of heating plates (5) and (6). The pressurized and heated sheet is taken off by a taking machine 7.

The temperature of the heating plate is set depending on the type of resin. It is necessary to change the material of the mold release material depending on the set temperature.

Pressure of pressure roller is 0.05Kg/cm~5Kg/cm
The range is adjusted according to the viscosity of the resin. If the pressure is low, voids will occur and the physical properties of the molded product will deteriorate. On the other hand, if it is too high, the resin flow will increase, making it difficult to control the thickness of the thin plate and the fiber volume content.

Two or more pressure and heat rollers can also be provided. This method is preferable because pressure is applied repeatedly to the sheet during the forming process, which improves the flatness of the sheet, reduces voids, and reduces disturbance in the orientation of the fiber reinforcement.

It is preferable to keep the area heated by the heating platen and pressure heating roller warm.

It is also possible to pull out the thermosetting resin before it is completely cured.

To determine the degree of hardening when pulling out during curing, there is a method of measuring and comparing the reaction heat of the prepreg and the thin plate in the middle of curing using a thermal differential scanning calorimeter (DSC) to determine the degree of curing.

According to this method, if the thin plate is removed from the molding machine when the degree of hardening is 65% or more, it can be taken out even if it is not completely cured, and in the next step, it can be completely cured without deformation by heating in an oven or the like.

〔Effect of the invention〕

According to the present invention, the following effects can be obtained.

It is easy to mold long objects.

In vacuum bag molding, autoclave molding, etc., there is a limit to the length of the molded product, but according to the method of the present invention, there is no particular restriction on the length of the molded product.

The thickness of the molded plate is arbitrary.

Although it was possible to make long molded plates using conventional pultrusion molding, it was necessary to change the mold when the thickness of the molded plate changed.

However, according to the method of the present invention, such complexity is not required, and molded plates with different thicknesses can be obtained simply by adjusting the distance between the roller and the hot platen.

No disturbance occurs in the orientation of the fiber reinforcement.

In the case of pultrusion, the orientation is disturbed due to the pressure generated in the mold, but in the present invention, the molded product is sandwiched between mold release materials and passes through the process, so the molded product is directly placed on the heating platen and pressure roller. Don't touch it,
Therefore, it is effective in stabilizing the process and preventing disturbances in fiber orientation.

Molding speed is fast.

In pultrusion molding, the molding speed is limited by the pull-out load of the molded product, but in the present invention, the pressure roller rotates in accordance with the molding speed, so there is a large degree of freedom in the molding speed.

High thermal efficiency and uniform heating.

In the present invention, since heating is performed on a hot platen which allows the curing reaction to occur uniformly through uniform heating, compared to the case where the upper and lower surfaces are heated using heated rollers, heating is performed on the surface, so that the thermal efficiency is high and the heating is uniform.

〔Example〕

Example 1 A continuous sheet of 2 plies of unidirectionally oriented epoxy resin prepreg Q-1112 (manufactured by Toho Rayon Co., Ltd., curing temperature 130°C) with a basis weight of 270 g/m ² was laminated as shown in Fig. 2. Set to unwinder. Both sides of this prepreg were covered with process release paper so as to be in close contact with each other, and the prepreg was introduced into a molding machine. The temperature of the heating plate and heating roller was 150°C, and seven pressure heating rollers were used. A prepreg with process release paper adhered to both sides was heated to 150°C on a hot plate in a molding machine, and while curing, pressure was repeatedly applied with a roller at a linear pressure of 0.1 kg/cm to form a laminate.

Residence time of prepreg laminate sheet on hot platen
The carbon fiber-reinforced thermosetting resin plate obtained by continuous heat treatment and curing for 10 minutes had a thickness of 0.59 mm and a fiber volume content of 51% capacity.

The molded plate had a good appearance with no irregularities or disordered fiber orientation, and no internal voids were observed.

[Brief explanation of the drawing]

In FIG. 1 and FIG. 2, 1 is prepreg;
2 is an unwinder, 3 is a processing paper, 4 is a nip roller, 5 is a heating plate, 6 is a pressurized heat roller, 7 is a take-up machine, and 8 is a cutting machine.

Claims (1)

[Claims] 1. A fiber reinforced sheet and a thermosetting resin are sandwiched between mold release materials and are continuously fed between a hot platen and a pressure heating roller, and the thermosetting resin undergoes a curing reaction under pressure. A continuous molding method for a fiber-reinforced thermosetting resin molded plate, characterized in that the sheet is conveyed while being carried out. 2. The continuous molding method according to claim 1, in which pressure is repeatedly applied between a heating platen and two or more pressure heating rollers. 3 The pressure applied to the heating plate and pressure heating roller is 0.05~
The continuous molding method according to claim 1, wherein the molding rate is 5Kg/cm.