JPH07144372A - Manufacture of fiber reinforced thermoplastic resin composite pipe - Google Patents

Abstract

PURPOSE:To easily manufacture a fiber reinforced thermoplastic resin composite pipe having excellent strength without peeling of an interface of a surface layer and a synthetic resin pipe. CONSTITUTION:A bundle of fibers consists of two kinds of fibers having different softening temperatures. One of the fibers which has lower softening temperature is of a thermoplastic resin fiber with a thermoplastic resin pipe and a heat fusing property. On the outer periphery of the thermoplastic resin pipe, the bundle of the fibers is wound or braided so as to provide a surface layer on the thermoplastic resin pipe. In a first process, a laminated thermoplastic resin pipe is manufactured. In a second process, the obtained laminated thermoplastic resin pipe is heated to above the softening temperature of the thermoplastic resin fiber having low softening temperature among the two kinds of fibers and to below the softening temperature of the fiber having high softening temperature among the two kinds of fibers, and the thermoplastic resin pipe and the surface layer are fused and integrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber-reinforced thermoplastic resin composite pipe.

[0002]

2. Description of the Related Art Fiber-reinforced thermoplastic resin composite pipes are lighter in weight than metal pipes and do not rust, and have higher strength than thermoplastic resin pipes, so that they are members for piping and structural members. Is widely used as.

In Japanese Unexamined Patent Publication (Kokai) No. 57-100030, a glass roving impregnated with a thermosetting resin is surrounded along the axial direction on the outer surface of an extruded thermoplastic resin tube, and then a twill is further formed. Wrap the glass yarn in a hanging shape, cure with ultraviolet rays, far infrared rays to form an intermediate layer, and then
The surface of the intermediate layer is coated with a thermoplastic resin to form a protective layer,
A method of making a fiber reinforced thermoplastic resin composite tube is disclosed. Further, JP-A-2-165930 discloses a method of producing a fiber-reinforced thermoplastic resin composite pipe by winding a fiber composite material composed of a thermoplastic resin and continuous fibers around the outer periphery of the thermoplastic resin pipe. There is.

However, in the former case, since the thermosetting resin is used for the intermediate layer, the thermoplastic resin tube, the intermediate layer, and
There is a problem that the adhesion between the intermediate layer and the protective layer is insufficient and peeling occurs at the interface. Further, in the latter, since the fiber composite material to be wound lacks flexibility, it is necessary to soften the fiber composite material by heating or the like when winding it around a pipe. For this reason, since air is entrained during winding, the adhesion between the tube and the fiber composite material deteriorates, and there is a problem that the interface peels off when used for a long period of time or under high temperature and high pressure.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method capable of easily producing a fiber-reinforced thermoplastic resin composite tube having excellent adhesion and strength between a surface layer and a thermoplastic resin tube.

[0006]

The thermoplastic resin constituting the thermoplastic resin tube used in the present invention may be appropriately selected according to the intended use of the fiber-reinforced thermoplastic resin composite tube, and is not particularly limited. No, for example, polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene,
Examples thereof include polystyrene, polyamide, polycarbonate, polyphenylene sulfide, polysulfone, and polyether ether ketone.

The thermoplastic resins may be used alone or in combination, and if necessary, they may be heat stabilizers, plasticizers, lubricants, antioxidants, ultraviolet absorbers, etc. within the range not impairing the physical properties. Pigments, inorganic fillers, fibers, fillers, processing aids, modifiers and the like may be added. The method for manufacturing the thermoplastic resin tube is not particularly limited, and examples thereof include a method of manufacturing using an extrusion method.

Of the two types of fibers used in the present invention, the thermoplastic resin fiber having a low softening temperature is not particularly limited as long as it has a heat fusion property with the thermoplastic resin tube. For example, aramid, Examples thereof include thermoplastic resin fibers made of nylon, polypropylene, polyethylene, polyvinyl alcohol, polyoxymethylene, polyethylene terephthalate, and the like.

Here, the same thermoplastic resin is used for the combination of the thermoplastic resin forming the thermoplastic resin tube and the thermoplastic resin forming the thermoplastic resin fiber having a low softening temperature of the two types of fibers. Are preferred, but may be different, for example, in the case of polypropylene, the latter is polypropylene and polyethylene as the latter, and in the case of polyamide, the latter is nylon and polyethylene terephthalate as the latter, and the former is In the case of polycarbonate, polyethylene terephthalate is preferred.

Of the two types of fibers used in the present invention, the fiber having a high softening temperature is not particularly limited, and for example, the thermoplastic resin fiber having a low softening temperature of the above two types of fibers can be used. Fibers made of a thermoplastic resin similar to a plastic resin; inorganic fibers such as glass fibers, carbon fibers, metal fibers; organic fibers made of silk, cotton, cellulose, hemp, etc., and particularly glass fibers and carbon fibers. To use
A fiber-reinforced thermoplastic resin composite tube having excellent strength is obtained, which is preferable.

Further, the softening temperature is equal to or higher than the softening temperature of the thermoplastic resin fiber having a low softening temperature of the two types of fibers and lower than the softening temperature of the fiber having a high softening temperature of the two types of fibers. Certain fibers may be mixed as appropriate.
Incidentally, such a fiber is a fiber made of the above thermoplastic resin,
Either inorganic fibers or organic fibers may be used.

If the average diameter of the above fibers is large, the flexibility of the fibers is reduced, making it difficult to wind or braid the fibers.
Further, if the fiber is thin, the fiber may be broken during winding or braiding, so 1 μm to 1 mm is preferable.

If the number of fibers in the fiber bundle used in the present invention is small, the fibers may be broken at the time of winding or braiding, and if the number of fibers is large, the fiber bundle becomes too thick and winding or braiding may occur. Since it may become difficult and the fusion property of the interface between the surface layer of the obtained fiber-reinforced thermoplastic resin composite pipe and the thermoplastic resin pipe may decrease, 100 to 100,000 is preferable.

If the diameter of the fiber bundle is large, winding or braiding will be difficult, and if it is thin, the fiber bundle may be broken, so 0.1-10 mm is preferable.

The form of the fiber bundle is not particularly limited, and a roving form, a strand form, a yarn form or the like may be appropriately selected depending on the use and the diameter of the fiber-reinforced thermoplastic resin composite pipe obtained. .

When the amount of the thermoplastic resin fiber having a low softening temperature in the fiber bundle is low, the heat fusion property between the thermoplastic resin tube and the surface layer is lowered, and when the amount is high, the fiber-reinforced heat obtained is increased. Since the strength of the plastic-resin composite pipe decreases,
It is preferably about 90% by weight.

The first step of the present invention is to wind or braid a fiber bundle around the outer periphery of the thermoplastic resin tube,
This is a step of producing a laminated thermoplastic resin tube by providing a surface layer on the thermoplastic resin tube.

The method of winding or braiding is not particularly limited. When winding, it may be wound in only one direction, or may be wound from multiple directions, but winding from multiple directions improves the internal pressure resistance and impact resistance of the resulting fiber-reinforced thermoplastic resin composite pipe, It is suitable.

The winding angle is not particularly limited, but if the angle is small, the pressure resistance of the resulting fiber-reinforced thermoplastic resin composite tube will be reduced, and if it is large, the productivity of the fiber-reinforced thermoplastic resin composite tube will be reduced. Therefore, it is preferable to wind it at 30 to 85 °.

When braiding, a braid forming machine (brader) can be used. The angle of the braid is not particularly limited, but for the same reason as in the case of winding, the angle between the braided fiber bundles is 30 to 170 ° when viewed from the longitudinal direction of the fiber-reinforced thermoplastic resin composite pipe. Preferably braided to

Further, when the fiber bundle is wound or braided, it is preferable to provide an inner core on the inner surface of the synthetic resin tube because it can prevent deformation of the synthetic resin tube and improve molding stability. Is.

In the second step of the present invention, the obtained laminated thermoplastic resin tube is treated at a temperature equal to or higher than the softening temperature of the thermoplastic resin fiber having a lower softening temperature of the two kinds of fibers and of the two kinds of fibers. In this step, the thermoplastic resin pipe and the surface layer are fused and integrated by heating to a temperature lower than the softening temperature of the fiber having a high softening temperature.

The softening temperature in the present invention means the Vicat softening temperature in the case of thermoplastic resin fiber, the melting temperature in the case of inorganic fiber, and the burning temperature in the case of organic fiber. Vicat softening temperature is JIS
It can be measured according to K7206.

The heating of the laminated thermoplastic resin tube is performed at a temperature equal to or higher than the softening temperature of the thermoplastic resin fiber having a low softening temperature of the two types of fibers and higher than the softening temperature of the fiber having a high softening temperature of the two types of fibers. Must be low temperature.

At this time, it is preferable to heat the thermoplastic resin tube within a range in which it does not deform. Therefore, the softening temperature of the thermoplastic resin fiber that is softened by heating is preferably 50 ° C. or higher higher than the melting temperature of the thermoplastic resin tube.

Here, the melting temperature refers to a state in which the crystalline state of the thermoplastic resin is completely lost, and when the glass transition temperature is Tg, generally 3 × in the case of an asymmetric thermoplastic resin. In the case of a thermoplastic resin having Tg / 2 and symmetry, it can be obtained by an expression represented by 2 × Tg.

When the laminated thermoplastic resin tube is heated and the thermoplastic resin tube and the surface layer are fused and integrated, pressing the inside of the thermoplastic resin tube means that the thermoplastic resin tube and the surface layer are joined together. It is suitable because it improves the fusion property.

The degree of pressurization depends on the heating temperature,
If it is low, it is not effective, and if it is high, the thermoplastic resin tube may be damaged, so 0.1 to 10 kg / cm ² is preferable.

It is also preferable to provide a coating layer made of a resin on the outer surface of the obtained fiber-reinforced thermoplastic resin composite pipe because the strength of the fiber-reinforced thermoplastic resin composite pipe is improved.

[0030]

In the present invention, since the fiber bundle is directly wound around or braided on the outer surface of the thermoplastic resin tube, the fiber bundle and the thermoplastic resin tube are not heated and air is not trapped between the fiber bundle and the thermoplastic resin tube. Adhesion with the plastic resin tube can be improved. Further, since a part of the fibers in the fiber bundle is softened and the surface layer and the thermoplastic resin tube are fused and integrated, the fusion property between the two becomes excellent.

[0031]

【Example】

(Example 1) Polypropylene (Sumitomo Chemical Co., Ltd., trade name Sumitomo Noblen D501) was extruded using an extruder having a die provided at the tip to have an inner diameter of 25 mm and an outer diameter of 29 mm.
Thermoplastic resin tube made of polypropylene (melting temperature 1
60 ° C.) is continuously extruded, and a fiber bundle made of polypropylene (softening temperature 150 ° C.) fibers and glass fibers (commercial yarn glass manufactured by Toyobo Co., Ltd.) is wound around the outer surface of the thermoplastic resin tube by using a winding machine. The fiber content (50% by weight) was wound in the left-hand direction with respect to the extrusion direction of the thermoplastic resin tube, and then in the right-hand direction from above.

The resulting laminated thermoplastic resin tube was placed at 180 ° C.
The polypropylene fiber is softened, the surface layer and the thermoplastic resin tube are fused and integrated, and the inner diameter is 25 mm and the outer diameter is 32 m.
m fiber reinforced thermoplastic resin composite tube was obtained.

The strength and interfacial peelability of the obtained fiber-reinforced thermoplastic resin composite pipe were measured by the following methods.

(Strength) Water at 85 ° C. under a pressure of 10 kg / cm ² was continuously flown into the obtained fiber-reinforced thermoplastic resin composite tube. As a result, there was no change in the fiber-reinforced thermoplastic resin composite tube after 3 hours.

(Interfacial Peeling Property) Water having a temperature of 80 ° C. and 25 ° C. was alternately flowed into the obtained fiber-reinforced thermoplastic resin composite pipe under a pressure of 1 atmosphere without applying pressure. This is 3,000, 5,0
After repeating 00, 10,000 times, the state of the interface between the surface layer of the fiber-reinforced thermoplastic resin composite pipe and the thermoplastic resin pipe was visually observed. As a result, even after the repetition of 10,000 times, the state of the interface did not change at all compared to the beginning.

(Example 2) In the same manner as in Example 1, while continuously extruding a thermoplastic resin tube made of polypropylene, the fiber bundle used in Example 1 was woven into a braid forming machine (Murata Machine Co., Ltd.). Attached to each bobbin of the brand name New Joint Braider manufactured by the company), on the outer surface of the thermoplastic resin tube,
Braiding was performed so that the angle between the fiber bundles was 90 ° C.

An inner stopper was attached to one end of the obtained laminated thermoplastic resin tube in the take-up direction, and an internal pressure generator (trade name AHV-8 manufactured by Shinko Sangyo Co., Ltd.) was used to apply pressure to 0.5 kg / cm ^2. , The laminated thermoplastic resin tube is heated to 190 ° C. to soften the polypropylene fiber, and the surface layer and the thermoplastic resin tube are fused and integrated, and then cooled, and the inner diameter is 25 mm and the outer diameter is 32 mm.
A fiber-reinforced thermoplastic resin composite tube was obtained. The strength and interfacial peelability of the obtained fiber-reinforced thermoplastic resin composite pipe were evaluated in Example 1
Measurement was carried out in the same manner as in, and the results are shown below.

(Strength) After 3 hours, there was no change in the fiber-reinforced thermoplastic resin composite tube.

(Interfacial peelability) After repeating 10,000 times, there was no change in the state of the interface between the surface layer and the thermoplastic resin tube as compared with the beginning.

(Comparative Example) Powdered polypropylene (Sumitomo Noblen D501, manufactured by Sumitomo Chemical Co., Ltd.) was adhered to glass fiber (trade name: Glass Roving RS440RR-517FS, manufactured by Nitto Boseki Co., Ltd.), and then heated and melted to give a width. Two
A cm fiber composite was obtained.

Then, in the same manner as in Example 1, while continuously extruding a thermoplastic resin tube made of polypropylene, the obtained fiber composite was used for 15 minutes with a winding machine.
While blowing soft air by blowing hot air at 0 ° C., the outer surface of the thermoplastic resin tube was wound in the same manner as in Example 1 to form a surface layer, thereby obtaining a multilayer thermoplastic resin tube.

The obtained multi-layered thermoplastic resin tube was heated at 180 ° C.
After heating, the polypropylene was softened, the surface layer and the thermoplastic resin tube were fused and integrated, and then cooled to obtain a composite tube having an inner diameter of 25 mm and an outer diameter of 32 mm. The strength and interfacial peelability of the obtained composite pipe were measured by the same method as in Example 1, and the results are shown below.

(Strength) After 25 minutes, the composite tube expanded and burst.

(Interfacial peelability) After repeating 3,000 times, there was no change in the interface between the surface layer and the thermoplastic resin tube as compared with the beginning, but the surface layer and the thermoplastic resin tube did not change. In the meantime, after repeating 5,000 times, peeling of 2 mm
After repeating 10,000 times, there was peeling of 5 mm.

[0045]

The method for producing a fiber-reinforced thermoplastic resin composite pipe of the present invention is as described above, and according to the present invention,
It is possible to easily manufacture a fiber-reinforced thermoplastic resin composite pipe having excellent strength without peeling at the interface between the surface layer and the thermoplastic resin pipe.

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Claims (1)

[Claims] 1. A fiber made of two kinds of fibers having different softening temperatures and having a low softening temperature on the outer periphery of a thermoplastic resin tube is a thermoplastic resin fiber having a heat fusion property with the thermoplastic resin tube. By providing a surface layer on the thermoplastic resin tube by winding or braiding the fiber bundle, the first step of producing a laminated thermoplastic resin tube and the resulting laminated thermoplastic resin tube, the two types of fibers Heats above the softening temperature of the thermoplastic resin fiber with a low softening temperature, and below the softening temperature of the fiber with the higher softening temperature of the two types of fibers, and fuses the thermoplastic resin tube and the surface layer together. The method for producing a fiber-reinforced thermoplastic resin composite pipe, which comprises the second step of: