JPH05116233A - Manufacture of fiber reinforced thermoplastic resin pipe - Google Patents

Abstract

PURPOSE:To simplify the manufacturing method of a subject pipe by inserting a prepreg composed of thermoplastic resin as its matrix and formed in the cylindrical shape into a cylindrical outer mold, disposing a heat-resistant film on the inner peripheral face of the prepreg, and then force feeding high temperature liquid. CONSTITUTION:A prepreg 2 composed of thermoplastic resin of high melting point or high softening point as its matrix formed into the cylindrical shape is inserted into a cylindrical outer mold 1 which is a metal pipe. A heat-resistant film 5 such as a polytetrafluoroethylene sheet is disposed on the inner peripheral face of the prepreg 21. Then, both ends of the cylindrical mold 1 are closed by plugs, and high temperature liquid of plasticizing temperature of thermoplastic resin constituting the prepreg 2 or over is force fed from liquid force feeding inlets formed on the plugs into a hollow section on the inside of the film 5. The prepreg 2 is pressed to the cylindrical outer mold 1 and thermoplastic resin is melted or softened by said process. The high temperature liquid is fed out and then the prepreg 2 and the film 5 are put into water together with the cylindrical outer mold 1 and cooled therein.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an advantageous method for producing fiber reinforced thermoplastic pipes.

[0002]

2. Description of the Related Art In general, continuous fiber reinforced composite materials (prepregs) having a matrix of so-called engineering plastics such as polyetheretherketone (PEEK) which is a thermoplastic resin have toughness, heat resistance and environment resistance. The properties are far superior to those of composite materials using a thermosetting resin such as epoxy resin as a matrix. In recent years, fiber reinforced thermoplastic resin pipes have been made with prepregs that use thermoplastic resin as a matrix, and the pipes have been tried to be used as structural members for bicycles, sports and leisure fields such as golf shafts and fishing rods, and aerospace fields. Came to be done.

In order to manufacture a fiber-reinforced thermoplastic resin pipe, first, a prepreg having a thermoplastic resin as a matrix is formed in a metal cylindrical outer mold 1 as shown in FIG. Load it. Next, as shown in FIG. 4, the rod-shaped core 3 is inserted into the hollow portion of the prepreg 2.
The core 3 is a thermally expandable one, and is specifically a solid or hollow mandrel made of a fluororesin. As a fluororesin, polytetrafluoroethylene (PTF
E, a trade name of Teflon), polyfluorinated alkoxyethylene resin (PFA), fluoroethylene propylene ether copolymer resin (FEP), and the like, which have large thermal expansion properties and high heat resistance, can be exemplified.

Then, the prepreg 2 and the core 3 are heated to a temperature not lower than the plasticizing temperature of the thermoplastic resin constituting the prepreg 2 to thermally expand the core 3 in the hollow portion of the prepreg 2 and melt the thermoplastic resin. At the same time, the prepreg 2 is clamped by the pressing force due to the thermal expansion of the core 3. Then, the prepreg 2 and the core 3 are cooled together with the cylindrical outer mold 1,
By pulling out the core 3 from the hollow part of the prepreg 2 and removing the cylindrical outer mold 1, a pipe 4 made of a thermoplastic resin having a shape as shown in FIG. 5 can be obtained.

However, in the case of producing a fiber-reinforced thermoplastic resin pipe in this way, it is necessary to prepare a core having a size according to the specifications and to regenerate the core after use. There are problems that the manufacturing process becomes complicated and the core is expensive.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide an advantageous method for producing a fiber-reinforced thermoplastic resin pipe in which the production process is simplified. To do.

[0007]

According to the method for producing a fiber-reinforced thermoplastic resin pipe of the present invention, a prepreg having a thermoplastic resin as a matrix is cylindrically inserted into a cylindrical outer die, and A heat-resistant film body is arranged on the inner peripheral surface of the prepreg, and then a high-temperature liquid having a plasticizing temperature of the thermoplastic resin or higher is press-fitted into the hollow portion inside the film body to melt or soften the thermoplastic resin. After that, the prepreg is cooled.

As described above, according to the present invention, since the core is not used as in the conventional case, the manufacturing process can be simplified. Hereinafter, the configuration of the present invention will be described in detail. In the present invention, first, a prepreg having a thermoplastic resin as a matrix is cylindrically inserted into a cylindrical outer mold, and a heat resistant film body is arranged on the inner peripheral surface of the cylindrical prepreg.

The cylindrical outer mold is the same as the conventional one as shown in FIG. 3, and is excellent in heat resistance capable of withstanding the temperature at the time of manufacturing the fiber reinforced thermoplastic resin pipe, for example, copper. Metal pipes such as pipes and iron pipes.
A prepreg using a thermoplastic resin as a matrix is, specifically, a fiber bundle, generally called tow, in which a plurality of continuous fibers are aligned and arranged in a band in one direction and impregnated with the thermoplastic resin of the matrix. Aligned prepreg (UD prepreg)). Not only does it have no tackiness or plasticity at room temperature, but it also has high rigidity. It has a sheet or strip shape (slit tape). As the reinforcing fibers used for the fiber bundle that constitutes this prepreg,
For example, carbon fiber, glass fiber and the like.

The thermoplastic resin of the matrix is not particularly limited, but is preferably polyether ether ketone (PEEK) having a melting point of 343 ° C., polyphenylene sulfide (PPS) having a melting point of 282 ° C. to 288 ° C., and a softening point of 219 ° C. Polyether imide (PEI), polyether sulfone (PE
S), polyarylene ketone, polyarylene sulfide, polyallylimide, polyamideimide, polyimide sulfone, polysulfone, polyester and the like can be exemplified by thermoplastic resins having a high melting point or a high softening point.
In particular, it is preferable to use a thermoplastic resin having a melting point of 200 ° C. or higher, which is called engineering plastic or super engineering plastic.

The heat-resistant film has excellent heat resistance capable of withstanding the temperature at the time of manufacturing the fiber-reinforced thermoplastic resin pipe, and examples thereof include a polytetrafluoroethylene (PTFE) sheet, a polyimide film, and an aluminum foil. Such as metal foil. In the present invention, as shown in FIG. 1, a prepreg 2 having a thermoplastic resin matrix is inserted into a cylindrical outer mold 1 in a tubular shape, and a heat-resistant inner peripheral surface of the tubular prepreg 2 is used. The film body 5 is arranged. In this case, the prepreg 2 may be inserted by inserting a tubular preform braided with strip-shaped prepregs into the cylindrical outer mold 1. Alternatively, a sheet-shaped prepreg may be spirally wound to form a cylindrical preform, which may be inserted into the cylindrical outer mold 1. The film body 5 is arranged, for example, by spirally winding the film body into a tubular shape, and inserting the tubular body into the hollow portion of the tubular prepreg 2 so as to be in close contact with the inner peripheral surface of the prepreg 2. According to

Next, in the present invention, after a high temperature liquid having a plasticizing temperature equal to or higher than the plasticizing temperature of the thermoplastic resin forming the prepreg 2 is pressed into the hollow portion inside the film body 5 to melt or soften the thermoplastic resin. Cool the prepreg 2. Film body 5
In order to press the high temperature liquid into the inner hollow portion of the cylinder, for example, as shown in FIG. 2, both ends of the cylindrical outer mold 1 are sealed with the stoppers 6, and the high temperature liquid is injected from the liquid pressure inlet 7 formed in the stopper 6. Just press fit. The high-temperature liquid is a liquid having a temperature equal to or higher than the plasticizing temperature of the thermoplastic resin forming the prepreg 2, and is not particularly limited, but for example, lithium nitrate is 35
A molten salt that is heated to a temperature of 0 ° C or higher to be melted, an alloy such as solder is heated to a temperature of 350 ° C or higher to be melted, a temperature that is equal to or higher than the plasticizing temperature of the thermoplastic resin that constitutes the prepreg 2. Heat-resistant oil such as silicone oil heated to above, another thermoplastic resin that is heated and melted at a temperature higher than the plasticizing temperature of the thermoplastic resin that constitutes the prepreg 2, or an inorganic or organic substance such as silicone rubber powder For example, a fine powder solid flowable substance (non-adhesive) is heated to a temperature equal to or higher than the plasticizing temperature of the thermoplastic resin forming the prepreg 2. The pressure at the pressure inlet is about 3 to 10 kg / cm ² .

By thus press-fitting the high-temperature liquid, the thermoplastic resin forming the prepreg 2 is melted or softened, and the prepreg 2 is pressed against the cylindrical outer mold 1 by the pressing force of the high-temperature liquid. As a result, the prepreg 2 is clamped. Then, the prepreg 2 is cooled. The cooling in this case can be performed, for example, by extracting the high-temperature liquid and throwing the prepreg 2 and the film body 5 together with the cylindrical outer mold 1 into water. Next, by removing the cylindrical outer mold 1 and the film body 5 from the prepreg 2, the pipe 4 made of a thermoplastic resin having a shape as shown in FIG. 5 can be obtained.

[0014]

【Example】

Example 1 In FIG. 2, a film of PTFE having a thickness of 50 μm was prepared as a film body 5 in a cylindrical shape and placed on the inner peripheral surface of the prepreg 2. As prepreg 2, PEEK / carbon (APC-2, ICI-Fibe
A prepreg (made by Rite Co., Ltd.) wound in a cylindrical shape was used. The cylindrical outer mold 1 and the stopper 6 are made of metal, and the stopper 6 is the membrane body 5.
It also serves as a seal and the entrance and exit of high-temperature liquid.

Silicone oil heated to 380 ° C. was introduced from the liquid pressure inlet 7 at a pressure of 3 kg / cm ² . Prepreg 2
Although the thermoplastic resin of No. 1 melted and the pressure decreased as the internal voids were eliminated, the pressure was compensated for and the pressure was maintained for about 90 seconds until the pressure decrease stopped. Then, the silicone oil was removed by suction, and the whole outer mold was poured into water to cool it, thereby obtaining a PEEK / carbon pipe.

Comparative Example 1 The same outer mold and prepreg as in Example 1 were used, but a PTFE core was inserted in the hollow part of the prepreg and these were used.
After heating for 60 minutes in an atmosphere of ° C, the whole was cooled to obtain a PEEK / carbon pipe similar to that in Example 1. This pipe showed no quality difference from the pipe obtained in Example 1. However, compared to Example 1, it took a long time to manufacture the pipe. That is, the manufacturing time in Example 1 was significantly shortened. Further, the PTFE core is expensive, and the recycling work of the core after use is complicated.

[0017]

As described above, according to the present invention, a prepreg having a thermoplastic resin as a matrix is inserted into a cylindrical outer mold in a cylindrical shape, and heat is applied to the inner peripheral surface of the cylindrical prepreg. A flexible film body, and then, in the hollow portion inside the film body, a high temperature liquid having a plasticizing temperature of the thermoplastic resin or higher is press-fitted to melt or soften the thermoplastic resin, and then the prepreg is formed. The following effects can be obtained for cooling.

(A) Compared with the case of using a heat-expandable core, the complexity of preparing cores each having a size according to the specifications can be avoided. (b) It is possible to avoid the complicated process of regenerating the core after use as in the case of using the heat-expandable core. (c) A pipe can be manufactured in a short time by press-fitting a high-temperature liquid, and the pressure can be easily controlled.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view showing a positional relationship among a cylindrical outer die, a prepreg, and a film body.

FIG. 2 is a cross-sectional view showing how a high-temperature liquid is press-fitted into a hollow portion inside a film body.

FIG. 3 is a perspective explanatory view showing a cylindrical outer die.

FIG. 4 is a perspective explanatory view showing a positional relationship among a cylindrical outer die, a prepreg and a core.

FIG. 5 is an explanatory perspective view showing an example of a fiber reinforced thermoplastic resin pipe.

[Explanation of symbols]

1 cylindrical outer mold, 2 prepreg, 3 core, 4
Pipe, 5 membranes, 6 stoppers, 7 liquid pressure inlet.

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Claims (1)

[Claims] 1. A prepreg having a thermoplastic resin as a matrix is cylindrically inserted into a cylindrical outer mold, and a heat-resistant film is disposed on the inner peripheral surface of the cylindrical prepreg.
Then, in the inner hollow portion of the film body, a high temperature liquid having a plasticizing temperature of the thermoplastic resin or higher is press-fitted to melt or soften the thermoplastic resin, and then the prepreg is cooled to heat the fiber reinforcement heat. Manufacturing method of plastic resin pipe.