JPH0443010A - Molding method for fiber reinforced thermoplastic synthetic resin - Google Patents

Abstract

PURPOSE:To carry out quenching without deforming a molded body by pressure molding a molded material sheet composed of a fiber reinforced synthetic resin prepreg material laminated sheet clamped by metallic sheets of enriched stretching properties in a heating chamber, jetting a refrigerant just after said pressure heating and cooling. CONSTITUTION:A molded material sheet 11 composed of laminated sheets 12 formed with prepreg material sheets of fiber reinforced thermoplastic synthetic resin clamped by metallic sheets 13 of enriched stretching properties is preheated and placed on a molding die 8 of a lower chamber 5, and the lower chamber 5 is lifted up, clamped by a flange section and set thereon. A compressor valve 17 is opened and a service water valve 19 and an exhaust valve 21 are closed to start a compressor 16, and compressed air is jetted out of a jetting tube 14 through an air-liquid mixer 18 to pressurize the molded material sheet 11. When the service water valve 19 and the valve 21 are opened after molding a molded body, the compressed air in an upper chamber 3 is exhausted out of an exhaust air tube 15 and a refrigerant formed with water and compressed air mixed in the mixer 18 are jetted out of the jetting tube 14 toward the molded body to cool the molded body.

Description

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

(Prior art) Fiber-reinforced synthetic resins are superior in specific rigidity and specific strength, which are rigidity and mechanical strength per unit weight, compared to metal materials, and it is also possible to design materials with characteristics that match specifications to some extent. , so-called chirad material,
It rapidly became popular in the aviation and space industries, as well as boats, ships, automobiles, and sporting goods.

Conventional fiber-reinforced thermoplastic synthetic resins were formed based on thermosetting synthetic resins, but recently, with the development of many high-performance thermoplastic synthetic resins, thermoplastic synthetic resins have been Also, some products have been developed.

As a fiber-reinforced thermoplastic synthetic resin, 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, Aro
A sheet material APC-2, which is a matic Polymer Composite made by reinforcing PEEK (polyetheretherketone) resin with carbon fibers, has been developed.

PEEKII resin has excellent heat resistance, steam resistance, chemical resistance, radiation resistance, flame retardancy, etc., and is used as electrical wire coating, computer wrapping wire, aircraft connectors and engine peripheral parts, and nuclear power generation connectors.

FRTP based on this PEEK resin is also expected to have a wide range of applications, as it is used in many applications such as hot water pumps.

Conventional molding of FRTP sheets involves hot press molding, in which a sheet of molding material heated to a predetermined molding temperature is set in a heated mold, and pressed inside a pressurizing chamber equipped with a mold in which the sheet of molding material is set. After heating to a predetermined temperature, compressed air is introduced and the molding material sheet is pressed to conform to the mold.

In the case of these moldings, the molded product was naturally cooled in the mold after molding, and then taken out.

(Problem to be Solved by the Invention) However, when a molded product is slowly cooled by natural cooling in a mold, the degree of crystallinity increases and the degree of crystallinity varies in the case of a crystalline synthetic resin such as PEEK resin. , the toughness and impact resistance will decrease, and the physical properties will vary.

This tendency is particularly strong in the case of resins such as PEEK resins that are formed at a high temperature of 400''C because it takes time to cool them down.

That is, the degree of crystallinity of a crystalline synthetic resin varies depending on the cooling rate after molding. For example, if the cooling rate is slowly cooled at 10° C./min or less, the degree of crystallinity increases and the toughness decreases, and conversely, Rapid cooling at a cooling rate of 700° C./min lowers the degree of crystallinity, resulting in lower mechanical strength, rigidity, chemical resistance, etc.

Therefore, in order to stabilize the physical properties of a crystalline synthetic resin molded product, it is necessary to strictly control the cooling rate after molding and optimally control the degree of crystallinity. This is difficult if the body is naturally cooled inside the mold.

For this reason, in the case of molded products based on crystalline synthetic resins, immediately after molding is completed, they are rapidly cooled to a state with a low degree of crystallinity, and then annealed at 200 to 300°C for about 20 minutes to reach the specified level. It is preferable to adjust the degree of crystallinity.

However, it is difficult to take out a molded product such as PEEK resin, which is heated to an extremely high temperature of about 400°C, from the mold immediately after molding and quench it with water cooling, etc. There was also the problem that it would become deformed.

The present invention solves the drawbacks of the prior art as described above, and
It is an object of the present invention to provide a method for molding a sheet-like molded material of a fiber-reinforced thermoplastic synthetic resin, in which a quenching operation immediately after molding of the molded object can be easily performed without deforming the molded object.

(Means for Solving the Problems) That is, the present invention comprises a laminated sheet in which a predetermined number of fiber-reinforced thermoplastic synthetic resin prepreg sheets are laminated and sandwiched between highly malleable metal sheets on both sides to form a molded material sheet,
This molded material sheet is pressure-molded using compressed air based on a mold in a pressurizing chamber located within the heating chamber, and the molded product is cooled by injecting refrigerant from a nozzle located within the pressurizing chamber immediately after molding. This is a method for molding a fiber-reinforced thermoplastic synthetic resin.

(for production) The present invention is configured as described above, and the molded article is as follows.

Immediately after molding, the molded product is efficiently quenched by injection of refrigerant, so the crystallinity of the molded product is extremely low.Moreover, since this cooling is local to the molded product, the room temperature inside the heating chamber hardly drops, allowing for short molding. Molding can be done in a cycle, and since the synthetic resin sheet is molded and cooled while being sandwiched between metal sheets on both sides, the reinforcing fibers are not oriented or damaged during molding and can be molded well. Furthermore, the molded body does not deform even if high-pressure refrigerant is injected during cooling.

(Example) As an example of the present invention, first, an apparatus for forming a forming material sheet by air pressure forming will be described with reference to FIG.

In FIG. 1, (1) is a heating chamber in which hot air circulates, and a pressurizing chamber (2) is provided within this heating chamber (1).

The pressurized chamber (2) has an opening at the bottom, and an upper chamber (3) that has a flange (4) around the opening and is fixed in a predetermined position.
, the position opposite to the opening of the upper chamber (3) on the top surface opens,
This opening has a flange portion (6) around it and is divided into two parts by a plunger rod (10) into a lower chamber (5) which is vertically movable.

The lower chamber (2) is provided with an exhaust port (7), and a mold (8) made of an air-permeable material such as ceramics is housed with the cavity portion (9) facing the opening.

(11) is a molding material sheet made by stacking a predetermined number of FRTP prepreg material sheets (12) between upper and lower surfaces of highly malleable metal sheets (13). 11) is the upper chamber (
3) and the lower chamber (5), there is a plunger rod (10
), the peripheral portion is sandwiched and set by the flange portions (4) and (6) provided around the openings on both the upper and lower surfaces.

(14) is an injection pipe for injecting compressed air for pressure molding and refrigerant for cooling into the upper chamber (3) of the pressurizing chamber (2), and this injection pipe (14) is connected to the compressor. Valve (17
) to the compressor (16) and the water valve (19).
) to the water pipe (20) through a gas-liquid mixer (1
8).

(15) is an exhaust pipe that is released to the atmosphere via an exhaust valve (21) for exhausting the inside of the upper chamber (3) of the pressurizing chamber (2) as necessary.

Next, the procedure of molding using the molding apparatus configured as described above will be explained.

First, as shown in Figure 2, the heating chamber (1) is heated to 400°C, which is the molding temperature of the PEEK resin that is the base of the molding material, and the lower chamber (5) of the pressurizing chamber (2) is lowered. It is in an open state, and 40 mm is placed on the mold (8) in the lower chamber (5).
A molding material sheet (11) preheated to 0°C is placed.

As shown in FIG. 3, the laminated sheet (12) of the molding material sheet (11) is made of carbon fiber prepreg material (Kasei Fiberlite Co., Ltd., APC) with PEEK resin as a matrix material.
-2, density 1.6 g/ad, carbon fiber volume fraction 61%,
A sheet of 0.125 mm thick (resin content 32%) (2
2) is a four-layer stack with the fiber orientation shifted by 45°C,
These two sets are stacked with a total of eight sheets, and the metal sheet (13) sandwiching the laminated sheet (12) from both sides is a superplastic aluminum sheet (Sky Aluminum Co., Ltd., A7475) with a thickness of 0.8 mm. .

Next, as shown in FIG. 4, the pressurizing chamber (2) raises the lower chamber (5) by operating the plunger rod (10), and moves the forming material sheet (11) between the lower chamber (5) and the upper chamber. Set the periphery between the chamber (3) and the flange provided around the opening, and set the compressor with the compressor valve (17) open and the water valve (19) and exhaust valve (21) closed. Activate (16) and gas-liquid mixer (18)
Compressed air at a pressure of about 6 kgf/cd is ejected from the injection pipe (14) to pressurize the forming material sheet (11).

As a result, the laminated sheet (12) heated to a predetermined molding temperature gradually deforms following the cavity (9) of the mold (8), and at this time, the laminated sheet (12) - (
The metal sheet (13) sandwiching the laminated sheet (12) from both sides is also a superplastic aluminum sheet with excellent malleability and deforms together, preventing the fiber orientation of the laminated sheet (12) from being disturbed by deformation.

Moreover, when the molding material sheet (11) deforms, the mold (8)
) is a ceramic type with breathability.

The air in the cavity (9) is discharged out of the mold (8) through the exhaust port (7) provided in the lower chamber (5) by the pressing force caused by the deformation of the molding material sheet (11), and the molding material sheet (11) - (11) becomes more easily deformed by the pressurizing force of compressed air, and eventually it comes into close contact with the cavity (9) and is formed into a shape that completely imitates the cavity, and in this state is pressurized for a predetermined time. The continuation forms a molded body.

Next, the water valve (19) and exhaust valve (21) are opened to cool the molded body formed as described above.

As a result, the compressed air for pressurization in the upper chamber (3) is discharged into the atmosphere from the exhaust pipe (15), and the inside of the pressurizing chamber (2) returns to atmospheric pressure, as shown in FIG. Mixer (18
), the refrigerant mixed with water and compressed air is sent to the injection pipe (14).
) towards the molded body (23) and then the exhaust pipe (
15), and the molded body (23) is cooled.

The amount of refrigerant injected during this cooling is 300 cc/min of water;
The amount of compressed air is 294 NQ/min, and the amount of injection from the injection pipe (14) is greater than the amount of exhaust from the exhaust pipe (15), so the compact (23) is cooled while being pressurized. There will be.

In the molded body (23), the surface of the molded product (24) formed by the laminated sheet (12) is covered with a metal cover (25) formed by the metal sheet (13), so that the refrigerant is directly formed. Since the refrigerant is not injected onto the surface of the molded product (24), the surface of the molded product (24) will not be deformed by the injection pressure of the refrigerant.

Further, as the refrigerant, in addition to the above-mentioned compressed air containing water mist, it is also possible to use adiabatic expanded air, water shower, and the like.

When the molded body (23) has been cooled as described above, the compressor valve (17), water valve (19) and exhaust valve (21) are closed, and the plunger rond (10) is closed as shown in FIG. The lower chamber (5) of the pressurizing chamber (2) is lowered by the operation of the pressurizing chamber (2), the molded body (23) is removed from the mold (8), and the next annealing process is started to readjust the degree of crystallinity.

(Effect) FIG. 7 shows the cooling effect of the present invention, and A shown by the solid black circle is the cooling curve of the molded product when the rapid cooling of the present invention is performed.
B, indicated by a white dotted line, is a cooling curve obtained by naturally cooling a molded product at room temperature as a comparative example.

As is clear from this figure, the cooling rate when cooling was performed under the conditions shown in the above embodiment according to the present invention was 5.
Extremely fast at 200℃/min, molded products at 400℃ can be processed 4 to 5 times.
The molded product can be cooled to room temperature in an extremely short time of seconds, and although the surface of the molded product is covered with a metal cover, this metal cover is made of an aluminum sheet with good thermal conductivity, so it does not affect the cooling rate of the molded product. has almost no effect.

As a result, the molded article is taken out from the mold in a state in which crystallization has hardly progressed, and an optimum degree of crystallinity can be achieved by the subsequent annealing treatment.

Furthermore, the cooling time for the molded product is short and it can be taken out from the mold immediately after the completion of molding.Moreover, since the cooling is local to the molded product and the time is short, there is almost no drop in the temperature of the heating chamber. Since no adjustment time is required, the molding cycle is extremely short.

As described above, the present invention provides a thermoplastic synthetic resin, particularly a sheet-like fiber-reinforced thermoplastic synthetic resin molded material based on a crystalline thermoplastic synthetic resin, by adjusting the degree of crystallinity and eliminating variations in physical properties. The object of the present invention is to provide a molding method that can easily mold a good molded product without any blemishes.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a molding device used in the present invention, Fig. 2 is a diagram showing a state in which a molding material is set in the device, and Fig. 3 is a diagram showing a state in which prepreg material sheets are laminated to form a laminated sheet. , FIG. 4 is a diagram showing the molding state, FIG. 5 is a diagram showing the cooling state of the molded product, FIG. 6 is a diagram showing the molded product taking out state, and FIG. 7 is a diagram showing the cooling effect. (1)... Heating chamber, (2)... Pressurizing chamber, (8)...
・Molding mold, (11)...Molding material sheet, (12)...
・Laminated sheet, (13)...Metal sheet, (14)
... Compressed air and refrigerant injection pipe, (16) ... Compressor, (18) ... Gas-liquid mixing device, (20) ...
・Water pipe, (23)... Molded object. Figure Figure Figure Answer 0 Lu 剋drive

Claims (1)

[Claims] A laminated sheet made by laminating a predetermined number of fiber-reinforced thermoplastic synthetic resin pre-prepared material sheets is sandwiched between highly malleable metal sheets on both sides to form a molded material sheet, and this molded material sheet is heated in a pressurized chamber located within a heating chamber. A method for molding a fiber-reinforced thermoplastic synthetic resin, which comprises pressurizing a mold using compressed air and cooling the molded product by injecting a refrigerant from a nozzle placed in a pressurizing chamber immediately after molding. .