JPH03256724A - Molding method for fiber reinforced thermoplastic synthetic resin - Google Patents

Abstract

PURPOSE:To quench a molded product easily without generating deformation just after molding by laminating fiber reinforced thermoplastic synthetic prepreg sheets, molding a material clamped by means of metallic sheets of rich stretching properties from both sides, applying water while a metal wire material having plastic deformation properties in a cooling mold of same shape having water-through properties while retaining a molded product just after cooling, and quenching. CONSTITUTION:A sheet-shaped molding material 5 composed of overlapped fiber reinforced thermoplastic synthetic resin prepreg sheets 6 and clamped by means of metallic material sheets 7 rich in stretching properties from both surfaces, up and down, are clamped between a pressurizing chamber 1 and an opening of a mold retaining chamber 3 and shaped following a cavity of a mold 8 by heating and pressurizing by a heating oven 11 in which both chambers 2 and 3 are accommodated. Then, a metal wire material 18 having plastic deformation properties is filled in a cooling frame 15 and pressed by a press platen 19 to form cooling molds 24 and 25 having water-through properties. A core side cooling mold 24 is accommodated in the cooling frame 15 to be used as a top force 22, and a molded product 21 released just after the completion of molding is set in a cooling device working as a bottom force 23 in which a cavity side cooling mold 25 is accommodated and the mold is closed. Then, high pressure water is applied from a water-through hole 16 of the cooling frame 15 through into a water drain outlet 17 to cool a molded product 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for molding synthetic resin, and particularly to a method for molding using a prepreg sheet of fiber-reinforced thermoplastic synthetic resin.

[Conventional technology]

Fiber-reinforced synthetic resins have better specific rigidity and specific strength, which are rigidity and mechanical strength per unit weight, than metal materials, and because it is possible to design materials with characteristics that match specifications to some extent, they are called chilled materials. It is rapidly becoming popular in the aviation and space industries, as well as boats, ships, automobiles, and sports-related industries.

Fiber-reinforced synthetic resins have traditionally been formed using thermosetting synthetic resins as base resins, but recently, as many high-performance thermoplastic synthetic resins have been developed, thermoplastic synthetic resins are also being used as base resins. A sheet-like fiber-reinforced thermoplastic synthetic resin in which continuous fibers are impregnated with a thermoplastic synthetic resin, that is, an FRTP sheet, has been developed as a so-called stampable sheet for press molding.

As this FRTP sheet, A
ro@atic Polymer Composi
A sheet material (AP C-2) made of PEEK (polyether ether ketone) resin reinforced with carbon fiber was developed as a te. PEEK resin has properties such as heat resistance, steam resistance, chemical resistance, radiation resistance, etc. This PEE is of excellent quality and is used in numerous applications such as electrical wire coating, computer wrapping wire, aircraft connectors and engine peripheral parts, nuclear power generation connectors, and hot water pumps.
FRTP based on K resin is also expected to have a wide range of applications.

Conventional methods for forming FRTP sheets include a hot press bottom shape in which a molding material heated to a predetermined molding temperature is set in a heated mold and pressed, and a pressurizing chamber equipped with a mold in which the molding material is set. This is done by pneumatic molding, in which compressed air is introduced after heating the material to a predetermined temperature, and the molded material is pressed to conform to the mold.
After molding was completed, the molded product was cooled to a predetermined temperature within the mold and then taken out from the mold.

[Problem to be solved by the invention]

F whose base resin is crystalline resin such as PEEK resin.
When molding an RTP sheet, a problem arises in that variations in the degree of crystallinity of the molded product affect physical properties.

In other words, the degree of crystallinity of a molded product varies depending on the cooling rate after molding. For example, if the cooling rate is slowly cooled at 10°C/min or less, the crystallinity will increase and the toughness will decrease, and if the cooling rate is 700°C or less, the crystallinity will increase. When the material is rapidly cooled to 1/min, the degree of crystallinity decreases, resulting in a decrease in strength, rigidity, chemical resistance, etc.

Therefore, in order to control the crystallinity of the molded product, it is necessary to strictly control the cooling rate after molding, but this is not easy with the conventional molding method using in-mold cooling as described above. Variations in physical properties occur in molded products due to variations in crystallinity.

For this reason, when molding a molding material based on crystalline synthetic resin, the molded product is once rapidly cooled to a low crystallinity state immediately after molding is completed, and then heated at 200 to 300°C - 200°C.
It is preferable to perform annealing for about 1 minute to return the crystallinity to a predetermined degree.

However, it is not easy to quickly cool a molded product at a high temperature of about 400° C. by water cooling or the like after taking it out of the mold, and there is a problem in that the molded product is deformed during this cooling process.

The present invention solves the above-mentioned drawbacks of the prior art, and provides sheet-like molding of fiber-reinforced thermoplastic synthetic resin that allows for easy quenching of a molded product immediately after molding without causing deformation of the molded product. The purpose of this invention is to provide a method for forming materials.

[Means to solve the problem]

That is, the present invention involves forming a molded material in which a predetermined number of fiber-reinforced thermoplastic synthetic resin prepreg sheets are laminated and sandwiched between highly malleable metal sheets from both sides using a mold,
The molded product taken out from the mold immediately after molding is held in a cooling mold formed by compression molding of a metal wire material with plastic deformability in the same shape as the mold and water permeable, and the molded product is rapidly cooled by passing water through it while holding the molded product. This is a method for molding a fiber-reinforced thermoplastic synthetic resin.

[For production]

The present invention is constructed as described above, and first, since the molded product is molded while being held by metal sheets from both sides, the molded product cannot be taken out from the mold immediately after molding is completed, even at a high temperature of 400°C. The molded product is then rapidly cooled while being held in the cooling mold, so the molded product is cooled without deforming at all.Moreover, the cooling mold has a water-permeable area that is compressed by compression molding of a metal wire with plastic deformability. A large water passage can be easily formed at low cost with a large cooling effect.

〔Example〕

Regarding embodiments of the present invention, first, the state in which a forming material sheet is formed by air pressure forming will be explained with reference to FIGS. 1 and 2.

In Figure 1, (1) is a pressurized chamber with an air supply pipe (9) for introducing compressed air, and (3) is a breathable mold (8).
) with the cavity facing the opening (1)
One mold holding chamber having a mold holding chamber (0) is disposed in a heating furnace (11) facing each other through an opening.

(5) is a sheet-shaped molded material made by stacking a predetermined number of FRTP prepreg material sheets (6) and sandwiching them between upper and lower surfaces of highly malleable metal sheets (7). is a flange portion (2) provided around the opening between the pressurizing chamber (1) and the mold holding chamber (3);
It is held in place by (4).

Next, to explain the specific conditions for molding, the prepreg material sheet (6) is a carbon fiber prepreg material (Kasei Fiberlite Co., Ltd., APC-2, density, 6i/ cxl
, a carbon fiber volume fraction of 61%, and a resin content of 32%) with a thickness of 0.125 mm were used, and the sheets were stacked in four layers with the fiber orientation shifted by 45 degrees as shown in Figure 3. A total of 8 sheets of these two sets are sandwiched between 0.8 m thick superplastic aluminum sheets (Sky Aluminum, A7475) as highly malleable metal sheets (7), and processed. Pressure chamber (1) and mold holding chamber (3)
was held between the openings.

A heating furnace (11) such as a circulating hot air stove that houses a pressurizing chamber (1) and a mold holding chamber (3) is maintained at 400°C, which is the molding temperature of PEEK resin, which is the base resin of the material to be molded. Therefore, after the molding material sheet (5) reaches 400°C, compressed air at a pressure of 6 kgf/cd is sent to the pressurizing chamber (1) to pressurize it.

As a result, the molding material sheet (5) heated to a predetermined molding temperature gradually deforms to follow the cavity of the mold (8), and at this time, the mold (8) is shaped like a concrete mold. Since the mold has good air permeability, the air inside the cavity is discharged out of the mold through the exhaust pipe (10) by the pressure caused by the deformation of the molding material sheet (5), further deforming it, and eventually it is released into the cavity. It fits tightly and is shaped to perfectly resemble the cavity.

If the molding material sheet (5) is kept pressed into the cavity of the molding die (8) for a predetermined period of time, the molding will end in the state shown in Fig. 2, but in this case, the prepreg material sheet (6) When a highly malleable metal material such as a superplastic aluminum sheet is used as the metal sheet (7) that sandwiches the material from both the upper and lower sides.

The metal sheet (7) closely adheres to the prepreg sheet (6) and is simultaneously deformed and molded.

Next, a method of forming a cooling mold for rapidly cooling the molded article formed as described above will be explained based on FIG. 4, which shows how to make a mold on the cavity side.

(12) is a concrete core mold housed in the formwork (14), and (13) is a capsule mold attached to the surface of the core mold (12) to compensate for the wall thickness of the product. , this capsule type 03) is based on the core type (12) and is made of a superplastic aluminum alloy sheet (7475) with a thickness of 0.8 m.
System) Two sheets were formed by pneumatic molding at 510°C and a pressure of 4 kgf/-.

(15) is a formwork (14) that accommodates the core mold (12).
) A water inlet (16) and a drain outlet (17) placed on top of the
This is a cooling formwork with 500 mm inside this cooling frame (15).
Filled with metal wire (18) that has plastic deformability like 0-series aluminum alloy cutting waste, and press this metal wire (18) with a pressure mechanism such as hydraulic pressure! (19) to form a cooling mold with water permeability.

(20) is an O-ring installed around the press plate (19), and by installing this O-ring (20), airtightness between the cooling formwork (15) and the press plate (19) is maintained. ,
It is possible to prevent water leakage when water is passed through the cooling mold, and furthermore, it is possible to prevent the occurrence of backlash when pressing the metal wire into the bottom shape, and to smoothly form the cooling mold.

A cooling mold on the core side is also formed in exactly the same manner as described above.
A method of rapidly cooling the molded product while holding it in the recooling molds on the cavity side and the core side will be explained with reference to FIGS. 5 and 6.

As shown in FIG. 5, the compression molding apparatus in which a cooling mold is formed from the plastically deformable metal wire is used as it is as a cooling device, and the core-side cooling mold (24) is attached to the cooling mold (15).
) is housed to form the upper mold (22), and the cavity side cooling mold (25) is stored to form the lower mold (23). First, set the mold with it open.

Next, as shown in Fig. 6, as soon as the molded product (21) is set in the mold, the mold is closed, and the cooling mold frame (15) is placed in the cooling mold (24) (25) on the core side and cavity side. )
High pressure water is passed through the water inlet to cool the molded product (21).

In this case, there is a difference in water pressure of approximately 2 kgf/J between the water inlet (16) and the drain outlet (17), so the molded product (21) is cooled and deformed while being pressurized from both the upper and lower sides. It is prevented.

After cooling, the molded product (21) is opened, taken out from the cooling device, and then subjected to an annealing process to readjust the primary crystallinity.

〔Effect of the invention〕

FIG. 7 shows the cooling effect of the present invention, where the curve a shown by solid black circles is the cooling curve when the cooling device of the present invention is rapidly cooled, and the curve b shown by dotted white circles is the cooling curve for a comparative example. This is a cooling curve when naturally cooled at room temperature.

From this figure, according to the present invention, the take-out temperature of the molded product, that is, the cooling start temperature, matches the molding temperature of 400°C, and the molded product has metal sheets attached to both the top and bottom surfaces, making it easy to handle. It is clear that the molding device was able to be taken out from the molding device and set in the cooling device immediately after the molding was completed, and that the cooling rate was extremely fast, as it was cooled from 400° C. to room temperature in less than 1 minute.

As a result, in the molded product after quenching, the crystallization of the crystalline synthetic resin has hardly progressed, and the degree of crystallinity can be easily readjusted to an appropriate state through the subsequent annealing treatment, resulting in improved physical and chemical properties. was able to prevent variations.

In addition, the molded product after quenching did not deform at all, no matter what shape it was in. This shows that although the method of forming the cooling mold is extremely simple, it corresponds well to the product shape. ing.

As described above, the present invention facilitates the production of appropriate products with excellent physical properties for sheet-like fiber-reinforced composites or resin molded materials based on thermoplastic synthetic resins, particularly crystalline thermoplastic synthetic resins. A molding method is provided.

[Brief explanation of drawings]

Figures 1 to 6 show examples of the present invention, Figures 1 and 2 show the molding state, Figure 1 before molding, Figure 2 after molding, and Figure 3 4 is a diagram showing a state in which prepreg material sheets are laminated, FIG. 4 is a diagram showing a method of forming a cooling mold, FIGS. 5 and 6 are in a quenched state, and FIG. 5 is before quenching.
FIG. 6 is a diagram showing the case of rapid cooling, and FIG. 7 is a diagram showing the rapid cooling effect. (5) Molding material sheet, (6) Prepreg material sheet, (7) Metal material sheet, (8) Molding die, (18) Metal wire, (21 )···Molding,
(24) (25)... Cooling type. Figure 1 Figure 2 Figure Figure Figure 7 Figure・-1-・a o----Ob Cooling time

Claims (1)

[Claims] A predetermined number of fiber-reinforced thermoplastic synthetic resin prepreg sheets are laminated and sandwiched between highly malleable metal sheets on both sides, and the molding material is molded using a mold, and a metal wire material with plastic deformability is molded into the mold. A fiber-reinforced thermoplastic synthetic resin characterized in that the molded product taken out from the mold immediately after molding is held in a cooling mold having the same shape and water permeability and formed by compression molding, and the molded product is rapidly cooled by passing water therethrough. molding method.