JPH044132A - Manufacture of fiber-reinforced thermoplastic resin pipe - Google Patents

Abstract

PURPOSE:To manufacture the above fiber-reinforced thermoplastic resin pipe superior in fiber reinforcing effect, by a method wherein a tapelike matter or a sheetlike matter comprised by fusing reinforcing fibers comprised of a large number of continuing filaments with thermoplastic resin is sued as a reinforcing fiber complex. CONSTITUTION:A tapelike reinforcing fiber complex 6 to be unwound through unwinder 5a, 5a of the first winding device 5 is wound spirally round the outer circumference of a resin pipe 3 extruded through a mold 2 of an extruding machine 1. Hot air through a hot air type heating device is blown against the circumference of the reinforcing fiber complex 6, the reinforcing fiber complex 6 is fused to the outer circumference of the resin pipe 3 and the first layer reinforcing layer is formed. Continuously, the tapelike reinforcing fiber complex 6 is wound round spirally in the opposite direction by the second winding device 5 and the second layer reinforcing layer is formed. The resin pipe 3 where reinforcing layer is formed is introduced into a crosshead mold 8, thereupon thermoplstic resin is melted and extruded to the outer circumference of the resin pipe 3 where the reinforcing layer is formed and a coating layer is formed. Then the same is cooled with a cooling device 9, received by a receiving machine 10 and a fiber-reinforced thermoplastic resin pipe 11 is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a fiber-reinforced thermoplastic resin pipe having excellent pressure resistance, impact resistance, hot water resistance, and the like.

(Prior art) Thermoplastic resin pipes such as vinyl chloride resin have superior properties such as being lighter and less susceptible to rust than metal pipes, and are widely used. Thermoplastic resin pipes are inferior to metal pipes in pressure resistance, impact resistance, hot water resistance, etc.

As a method for improving the performance such as pressure resistance, impact resistance, and hot water resistance of thermoplastic resin pipes, for example, Japanese Patent Application Laid-Open No. 63-1527
Publication No. 86 specifically discloses a method for manufacturing a fiber-reinforced thermoplastic resin pipe, which includes a step of winding a reinforcing fiber composite around the outer periphery of the thermoplastic resin pipe and fusing it.

In this case, the reinforcing fiber composite is a strand in which an aggregate of many continuous filaments to which thermoplastic resin powder is attached is coated with a thermoplastic resin that is the same as or compatible with the resin powder, or a strand made of this strand. A reinforced fiber composite composed of mat or cloth is used.

The reinforcing fiber composite is fused to the outer periphery of the thermoplastic resin pipe by heating and winding the reinforcing fiber composite around the outer periphery of the thermoplastic resin pipe immediately after extrusion molding. The most commonly used method is to completely melt and fuse the internal resin powder and the surface coating resin.

(Problem to be Solved by the Invention) In a method of manufacturing such a fiber-reinforced thermoplastic resin pipe, the internal thermoplastic resin powder adhering to a large number of continuous filaments is completely melted to achieve strong fusion. To achieve this, it is necessary to heat and maintain the surface of the resin pipe and the reinforcing fiber composite at a relatively high temperature, or to sufficiently heat the inside of the reinforcing fiber composite by lowering the line speed at a relatively low temperature.

However, when the surface of the resin pipe and the reinforcing fiber composite are heated and held at high temperatures, the resin pipe becomes excessively soft due to the heat. Such an excessively softened resin tube is easily deformed by the tension of the reinforcing fibers wound around it, making it difficult to obtain a fiber-reinforced thermoplastic resin tube with good dimensional accuracy. Therefore, the main method used is to slow down the line speed and heat and maintain the surface of the resin pipe and the reinforcing fiber composite at a relatively low temperature to sufficiently heat the inside of the reinforcing fiber composite. There is a problem in terms of productivity.

The present invention solves the problems of the prior art described above,
The aim is to efficiently produce fiber-reinforced thermoplastic resin pipes that do not cause deformation of the resin pipe, have good dimensional accuracy, have a strong fusion bond between the resin pipe and the reinforcing fiber composite, and have excellent fiber reinforcement effects. The purpose of the invention is to provide a method for manufacturing the same.

(Means for Solving the Problems) The method for manufacturing a fiber-reinforced thermoplastic resin pipe of the present invention includes a step of winding or surrounding a reinforcing fiber composite around the outer periphery of a thermoplastic resin pipe and fusing the reinforcing fiber composite. In the method for manufacturing a reinforced thermoplastic resin pipe, the reinforcing fiber composite is a tape-like or sheet-like product formed by reinforcing fibers made of a large number of continuous filaments fused together with a thermoplastic resin, and the thermoplastic resin pipe The reinforcing fiber composite is characterized by using a reinforcing fiber composite having a lower fiber content in the surface layer portion in contact with the surface layer than in other portions, thereby achieving the above object.

In the present invention, the thermoplastic resin constituting the thermoplastic resin pipe includes polyvinyl chloride, chlorinated polyvinyl chloride,
Examples include polyethylene, polypropylene, polystyrene, polyamide, polycarbonate, polyphenylene sulfide, polyarylether sulfone, polyarylether ketone, and the like.

These resins may be used alone or in combination with compatible resins. Additionally, additives such as heat stabilizers, lubricants, plasticizers, antioxidants, ultraviolet absorbers, pigments, fillers, processing aids, and modifiers may be added as necessary.

The thermoplastic resin pipe used in the present invention is obtained by melt extrusion molding the above thermoplastic resin, and such a resin pipe may be a single-layer pipe or a multi-layer laminated pipe.

The reinforcing fiber composite used in the present invention is a tape-like or sheet-like product formed by reinforcing fibers consisting of a large number of continuous filaments fused together with a thermoplastic resin. If the thickness of the tape-like material or sheet-like material is too thin, the reinforcing effect will not be sufficient, and if it is too thick, it will be difficult to wrap or surround it, so it is preferably used in the range of 0.1 to 2 MB. It will be done. In the case of a tape-like material, one having a width of 5 to 50+ nm is suitably used.

Reinforcing fibers consisting of a large number of continuous filaments include inorganic fibers such as glass fibers, carbon fibers, and metal fibers, and synthetic fibers such as aramid fibers and vinylon fibers, and have a diameter of 1 to 4 mm.
Rovings or yarns composed of tens to thousands of 0 μm filaments are commonly used. In addition, the thermoplastic resin to which such reinforcing fibers are fused is
A resin similar to that used for the thermoplastic resin pipe described above or a resin copolymerized with a heptamer capable of imparting adhesive properties, such as vinyl acetate, is used.

Therefore, in the tape-shaped or sheet-shaped reinforcing fiber composite, the fiber content of the surface layer portion in contact with the thermoplastic resin pipe is lower than that of the other portions. In this case, the fiber content of the surface layer in contact with the thermoplastic resin tube is preferably 0 to less than 10% by volume. Here, the surface layer of the reinforced fiber composite is approximately 1 to 30% of the total thickness of the fiber composite.
It means the % part.

Further, the ratio of the reinforcing fibers consisting of a large number of continuous filaments and the thermoplastic resin fused thereto is preferably in a range such that the content of the reinforcing fibers as a whole is 10 to 80% by volume. If the total reinforcing fiber content is less than 10% by volume, a sufficient reinforcing effect cannot be obtained. On the other hand, if the reinforcing fiber content exceeds 80% by volume as a whole, even if the fiber content in the surface layer is as low as less than 10% by volume, the cohesive force of the reinforcing fibers themselves will be small and the resin will not be sufficiently fused. A fiber-reinforced resin pipe with high strength cannot be obtained.

To manufacture the above-mentioned reinforcing fiber composite used in the present invention,
The following methods are mainly adopted.

First, reinforcing fibers in the form of rovings or yarns made of a large number of continuous filaments are opened and aligned, and passed through a fluidized bed of thermoplastic resin powder or through a dispersion of thermoplastic resin powder. After drying, the resin powder is impregnated and adhered to the gaps between the reinforcing fibers, and is passed through a heated pressure roll to melt the resin powder and form it into a tape or sheet.

At this time, a plurality of tape-shaped or sheet-shaped reinforcing fiber composites with different fiber contents are formed, and the reinforcing fiber composite with the lower fiber content is on the outside. A method is adopted in which the composite is laminated and bonded.

Alternatively, a reinforcing fiber composite in the form of a tape or sheet having the same fiber content throughout is formed in advance by the method described above, and a resin film is coated on one or both sides of this reinforcing fiber composite. A method of melt extrusion is also adopted.

Alternatively, a reinforcing fiber composite in the form of a tape or sheet having the same fiber content throughout is formed in advance by the method described above, and resin powder is applied to one or both sides of this reinforcing fiber composite. A method of melting the resin powder and molding it into a tape or sheet shape by adhering the resin powder and passing it through a heated pressure roll is also adopted.

In the present invention, it is particularly preferable to use a reinforcing fiber composite in which not only the surface layer in contact with the thermoplastic resin pipe but also the surface layer on the opposite side has a lower fiber content than the inner fiber content.

Hereinafter, the method of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a schematic explanatory diagram showing an example of the method of the present invention. In FIG. 1, 1 is a thermoplastic resin extruder. A molding die 2 for extruding and molding a thermoplastic resin into a hollow tube shape is attached to the tip of the extruder 1. Molding mold 2
Two sets of winding devices 5.5 for winding the tape-shaped reinforcing fiber composite 6 around the outer periphery of the thermoplastic resin pipe 3 are provided at the front end of the thermoplastic resin pipe 3.

Each winding device 5.5 is equipped with two bobbin-like unwinding machines 5a, 5a each winding a tape-like reinforcing fiber composite 6. is rotated, and a tape-shaped reinforcing fiber composite 6 is unwound from each unwinding machine 5a, 5a, and is spirally wound around the outer periphery of the resin pipe 3. In addition, 2&I
The winding devices 5, 5 of 1 are configured to rotate in mutually opposite directions.

Near the front of each winding device 5, 5 is a hot air heating device 4.4.
is provided so that the fiber composite 6 wound around the outer periphery of the resin tube 3 can be heated. Further ahead, there is an extruder 7 equipped with a crosshead mold 8 for coating the outer periphery of the resin tube 3 around which the reinforcing fiber composite 6 is wound with thermoplastic resin, and a cooling device 9 such as a water tank. , collection machine 10
are provided in this order.

First, the tape-shaped reinforcing fiber composite 6 unwound from the unwinding machines 5a, 5a of the first winding device 5 is placed around the outer periphery of the resin pipe 3 extruded from the molding die 2 of the extruder 1, so as to fill the gap. It is wound in a spiral to avoid overlapping or overlapping. Then, hot air from the hot air heating device W4 is blown around the reinforcing fiber composite 6, and the resin in the surface layer of the reinforcing fiber composite 6 that is in contact with the resin pipe 3 is heated and melted, thereby reinforcing the outer periphery of the resin pipe 3. The fiber composite 6 is fused to form a first reinforcing layer.

Subsequently, the tape-shaped reinforcing fiber composite 6 is spirally wound in the opposite direction to the first layer reinforcing fiber composite 6 by the second winding device 5, and the second layer is similarly wound. A reinforcing layer is formed. By winding the first and second reinforcing layers in opposite directions, the reinforcing fibers are less likely to shift even when stress is applied to the fiber-reinforced pipe, compared to when they are wound in the same direction. It is difficult to order and can exhibit excellent reinforcing effects.

As a method for forming the reinforcing layer of the reinforcing fiber composite 6 on the outer periphery of the resin pipe 3, the method of winding and fusing the reinforcing fiber composite 6 in the circumferential direction as described above is simple and reasonable. When strength in the tube axis direction is required, a method is adopted in which the reinforcing fiber composite 6 is surrounded and fused along the tube axis direction. In this case, the reinforcing fiber composite 6 may be in the form of a tape or a wider sheet.

In addition, when winding and fusing the reinforcing fiber composite 6 around the outer circumference of the resin tube 3, in order to further reduce the deformation of the resin tube 3, an extension core that protrudes in the extrusion direction of the molding die 2 is provided. There is a method of winding the reinforcing fiber composite 6 on the core, or a method of blowing cooling air into the resin tube 3 from the tip of the extrusion mold 2 to cool the inner surface of the resin tube 3 and winding the reinforcing fiber composite 6. A winding method may also be adopted.

The resin pipe 3 on which the reinforcing layer has been formed is then introduced into a crosshead mold 8 attached to an extruder 7, where a thermoplastic resin is melted and extruded to coat the outer periphery of the resin pipe 3 on which the reinforcing layer has been formed. A layer is formed. After that, the cooling device 9
The pipe is cooled and taken off by a take-off machine 10, and a fiber-reinforced thermoplastic resin pipe 11 is manufactured.

The tape-shaped reinforcing fiber composite 6 is manufactured by the method shown in FIG. That is, in Figure 2,
A reinforcing fiber 20 consisting of a large number of filaments is unwound from a bobbin, aligned in the longitudinal direction, and introduced into a fluidized bed 30 provided with a porous bottom plate 31. The reinforcing fibers 20 are usually introduced into the fluidized bed 30 or before they are introduced into the fluidized bed 30.
The fibers are opened by the defibrator 32 in the chamber.

In the fluidized bed 30, a powdered thermoplastic resin is blown up above a porous bottom plate 31 by air pressure and maintained in a floating state. The particle size of the powdered thermoplastic resin is generally about 10 to 200 μm. Then, the powdered thermoplastic resin suspended between the filaments of the reinforcing fibers 20 introduced into the fluidized bed 30 is impregnated.

The reinforcing fibers 20 impregnated with the powdered thermoplastic resin are passed through a heating furnace 40 and passed through a pair of heated pinch rolls 41 where they are heated and pressed, whereby the reinforcing fibers 20 are fused with the powdered thermoplastic resin. be done.

Subsequently, it passes through a pair of cooling pinch rolls 42 and is taken up by a pair of take-up pinch rolls 5o. In this way,
Two tape-shaped reinforced fiber composite materials 60 and 61 having different fiber contents are separately produced. These two tape-shaped reinforcing fiber composites 60 and 61 are thermocompression bonded in a separate process using a thermocompression bonding device (not shown) to produce the tape-shaped reinforcing fiber composite 6.

When this tape-shaped reinforcing fiber composite 6 is used to wrap or surround the outer periphery of the resin pipe 3 as described above, it is wound so that the side with the lower fiber content is in contact with the resin pipe 3. round or surrounded.

When fusing the wound or surrounding reinforcing fiber composite to the resin tube, the resin layer tube is immediately extruded from the molding die.
The reinforcing fiber composite may be quickly wound and fused, or the resin pipe may be cooled once and the resin pipe and reinforcing fiber composite may be simultaneously or separately coated on the surface of the resin pipe and the reinforcing fiber composite. After heating with hot air, an infrared heater, etc. to such an extent that the surface melts, the reinforcing fiber composite may be wound around the outer periphery of the resin tube and fused. When heating the resin pipe and reinforcing fiber composite, it is preferable to heat the resin pipe and the reinforcing fiber composite rapidly in a short period of time so that only the surface thereof is melted and the inside thereof is not melted.

Further, although an example in which two winding devices are provided has been described, the number thereof is not particularly limited and may be appropriately determined depending on the thickness of the reinforcing layer to be molded, desired strength, etc. For example, - pieces may be provided, or three or more may be provided.

In addition, as a method for winding a reinforcing fiber composite around a resin tube, an example was explained in which the resin tube is manufactured continuously while being extruded. After that, the resin tube may be rotated and wound.

Further, although an example using a reinforcing fiber composite manufactured in advance on a separate line has been described, the reinforcing fiber composite may be continuously wound or surrounded around the resin pipe while forming the reinforcing fiber composite.

Note that if a rolled or surrounded reinforcing fiber composite is present on the outer surface of the tube, it may be inconvenient as a product, so here is an example in which a thermoplastic resin is extruded and coated with a coating layer. Although described, the covering layer is not necessarily required.

(Function) As mentioned above, the reinforcing fiber composite is a tape-like or sheet-like material made by reinforcing fibers made of a large number of filaments fused together with a thermoplastic resin, and the surface layer in contact with the thermoplastic resin pipe is used as a reinforcing fiber composite. When using a reinforcing fiber composite with a lower fiber content than other parts, the reinforcing fibers are already fused and integrated with thermoplastic resin, so the surface of the resin pipe and the reinforcing fiber composite It is possible to quickly melt only the surface layer portion at a relatively low temperature to firmly fuse the two together.

Therefore, deformation of the resin tube is prevented and the line speed can be increased.

Note that since the reinforcing fiber composite is in the form of a tape or sheet, it can be wound or surrounded more efficiently than in the case of a strand-shaped reinforcing fiber composite. Furthermore, compared to reinforcing fiber composites formed into mats or cloths, the production of reinforcing fiber composites is also a more expensive product.

(Example) Examples and comparative examples of the present invention are shown below.

Slipper↓ In this example, a fiber-reinforced thermoplastic resin pipe was manufactured by the method shown in FIGS. 1 and 2.

As shown in Figure 1, polyvinyl chloride mixed with heat stabilizers, lubricants, etc. is extruded from a mold 2 at a temperature of about 180°C to form a resin tube 3 with an inner diameter of 23 mm and a wall thickness of 3 mm. did. Then, while heating the surface of the resin pipe 3 and the surface of the reinforcing fiber composite 6 to about 180°C using the hot air heating device 4, a tape-shaped reinforcing fiber composite 6 is attached to the outer periphery of the resin pipe 3.
was spirally wound and fused using a winding device 5 to form a first reinforcing layer. Subsequently, in the same manner, the tape-shaped reinforcing fiber composite 6 was spirally wound and fused in the opposite direction to the first layer to form a second reinforcing layer.

The tape-shaped reinforcing fiber composite 6 used here has a thickness of approximately 0.5 m, a width of approximately 201 Iffl, and a fiber content of the surface layer (approximately 0.05 m5) in contact with the resin pipe 3. Volume%, fiber content of other parts (approximately 0.45m) is 3
0% by volume.

This tape-shaped reinforcing fiber composite 6 is obtained by opening glass fiber rovings by the method shown in FIG. A tape-shaped reinforcing fiber composite 60 with a glass fiber content of 3% by volume and formed by impregnating the same, and a tape-shaped reinforcing fiber composite 61 with a glass fiber content of 30% by volume formed in the same manner. The copolymer powder was melted and integrated with glass fibers by thermocompression bonding at a temperature of about 180°C.

Next, the resin pipe 3 on which the reinforcing layer has been formed is introduced into the crosshead mold 8, and polyvinyl chloride is applied around the outer circumference of the resin pipe 3 at an angle of about 180°.
The pipe was coated at a temperature of C to form a coating layer, cooled by a cooling device 9, taken by a take-off machine 10, and cut into a predetermined length to produce a fiber-reinforced thermoplastic resin pipe 11. The line speed was 2 m/min, and the dimensional accuracy of the tube diameter was also good.

This fiber-reinforced thermoplastic resin pipe 11 was cut into 1 m lengths, and a cold/hot cycle test was conducted in which 90°C hot water and 25°C cold water were alternately passed through the pipe at 15-minute intervals for 5,000 cycles, but peeling between the eyebrows etc. No abnormalities were observed.

As a tape-shaped reinforcing fiber composite 6, after opening a glass fiber roving by the method shown in FIG. The thickness of the molded product impregnated with the combined powder is approximately 0.5
A tape-shaped reinforcing fiber composite having a width of about 20 mm and a glass fiber content of 30% by volume throughout was used. Other than that, the same procedure as in Example 1 was carried out.

The resulting fiber-reinforced thermoplastic resin pipe was cut into 1 m lengths, and a cold/heat cycle test was conducted in which 90°C hot water and 25°C cold water were alternately passed through the pipe at 15-minute intervals for 5,000 cycles. Glabellar peeling was observed between the fiber composite and the reinforcing fiber composite.

Therefore, in order to strengthen the fusion bond between the resin pipe and the reinforcing fiber composite, the heating temperature of the surface of the resin pipe 3 and the surface of the reinforcing fiber composite 6 by the hot air heating device 4 was made higher than in Example 1. As time progressed, the resin tube 3 deformed and the dimensional accuracy of the tube diameter decreased. In addition, the heating temperature of the surface of the resin pipe 3 and the surface of the reinforcing fiber composite 6 was the same as in Example 1, and the line speed was 2 m.
When changing from 0.5 m/min to 0.5 m/min, no peeling between the eyebrows was observed in the above-mentioned cold/heat cycling test, but productivity decreased.

(Effects of the Invention) Since the method for manufacturing a fiber-reinforced thermoplastic resin pipe of the present invention is configured as described above, the resin pipe does not deform and has good dimensional accuracy. A fiber-reinforced thermoplastic resin pipe with strong fusion bonding and excellent fiber reinforcement effects such as pressure resistance, impact resistance, and hot water resistance can be efficiently produced.

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic illustrations showing an example of the method of the present invention. 2... Molding mold, 3... Thermoplastic resin pipe, 4...
Hot air heating device, 5... Winding device, 6... Reinforced fiber composite, 8... Crosshead mold, 9... Cooling device,
]0,... Taking machine, 11... Fiber-reinforced thermoplastic resin pipe, 2o... Reinforcing fiber, 30... Fluidized bed, 41...
Heating pinch roll, 50...Take-back pinch roll, 60
．． 61... Reinforced fiber composite material.

Claims (1)

[Claims] 1. A method for producing a fiber-reinforced thermoplastic resin pipe, which includes a step of winding or surrounding a reinforcing fiber composite around the outer periphery of the thermoplastic resin pipe and fusing the same, wherein the reinforcing fiber composite comprises a large number of continuous filaments. A reinforcing fiber composite is a tape-like or sheet-like material made by reinforcing fibers fused together with a thermoplastic resin, in which the surface layer in contact with the thermoplastic resin pipe has a lower fiber content than other parts. A method for producing a fiber-reinforced thermoplastic resin pipe.