JPH05138758A - Production of fiber reinforced thermoplastic resin pipe - Google Patents

Abstract

PURPOSE:To efficiently produce a fiber reinforced thermoplastic resin pipe excellent in interlaminar bonding strength even when first and second reinforced layers are formed by employing an inner core system. CONSTITUTION:A double-layered pipe consisting of an inner thermoplastic resin layer B3 and a first reinforced layer A3 is introduced into an inner core 6c in such a state that it is held to the temp. range from the softening temp. of the matrix resin constituting the first reinforced layer A3 to below the m.p. thereof and a fiber composite C1 is wound around the inner core 6c at the outside position thereof at temp. below the m.p. of the matrix resin to form a second reinforced layer C2. By this constitution, the floating of the fibers forming the respective reinforced layers and the adhesion of the inner layer B3 to the inner core 6c are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a thermoplastic resin tube as the innermost layer, and a first reinforcing layer formed by arranging continuous reinforcing fibers in the longitudinal direction of the tube on the outermost layer. The present invention relates to a method for manufacturing a fiber-reinforced thermoplastic resin pipe having a second reinforcing layer formed by winding continuous reinforcing fibers around the outer periphery of a reinforcing layer.

[0002]

2. Description of the Related Art Conventionally, a reinforcing fiber impregnated with a liquid thermosetting resin is arranged on the outer surface of a thermoplastic resin tube which is an inner layer,
The composite pipe formed by heat-curing this to form a reinforced layer has a weak adhesive force with the thermoplastic resin pipe of the inner layer because the matrix resin of the reinforced layer is formed of a thermosetting resin, so that the composite pipe When used under high temperature conditions, there has been a problem that interfacial peeling occurs between both layers due to the difference in linear expansion coefficient between the thermoplastic resin tube of the inner layer and the reinforcing layer.

Therefore, in order to solve this problem, the present applicant uses a thermoplastic resin as a matrix resin for the reinforcing layer and forms a fiber composite in which the thermoplastic resin is held by continuous fibers. A first layer in which a continuous layer is arranged in the longitudinal direction of the pipe on the outer surface of the plastic resin layer as the innermost layer.
A composite pipe in which a reinforcing layer is formed, and further, a second reinforcing layer in which continuous fibers are wound and arranged in the circumferential direction of the pipe is formed on the outer side thereof, and a method for producing the composite pipe have been previously proposed (JP-A-3-15759).
(See Japanese Patent Publication No. 1).

According to this technique, the reinforcing fiber has a reinforcing layer having a two-layer structure of a first reinforcing layer arranged in the longitudinal direction of the tube and a second reinforcing layer arranged in the circumferential direction, and these. By using a fiber composite in which a thermoplastic resin is held in a large number of continuous filaments as a reinforcing fiber forming the reinforcing layer, it is possible to obtain one in which the thermoplastic resin is fused and integrated at the interface of each layer. What is done is the essence, but as an example of the method of forming the second reinforcing layer in the two-layer pipe consisting of the first reinforcing layer and the thermoplastic resin inner layer, the inner core is projected inside the two-layer pipe. Then, a method of winding the fiber composite around the inner core at a position outside of the inner core was proposed (see page 4, lower right column of the above publication). This is to prevent the two-layer tube which has not been sufficiently solidified from being deformed by winding the fiber composite.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in order to heat-seal and integrate the second reinforcing layer on the first reinforcing layer, the fiber composite for winding and the already formed first composite layer are formed. Since the reinforcing layer is wound while being heated to a temperature at which they can be mutually fused by the heat energy from the heat source, if the heating temperature is not precisely controlled, the matrix resin in the fiber composite will melt and its viscosity will increase. It may become low, and only the reinforcing fibers may be raised on the surface, and it may be difficult to sufficiently fuse the first and second reinforcing layers.

On the other hand, since the above-mentioned inner core system is adopted, the resin in the inner layer of the thermoplastic resin of the two-layer pipe cannot be cooled sufficiently when the production speed is relatively fast, so When sliding, the friction between the inner core and the inner surface of the thermoplastic resin inner layer becomes severe, and the resin adheres to the surface of the inner core, causing sliding between the inner core and the thermoplastic resin inner layer. In the case of lacking smoothness and extremeness, the reinforcing layer and the thermoplastic resin inner layer may be separated from each other, which may make it difficult to pick up.

The present invention solves the problems of the prior art as described above, uses a thermoplastic resin as the resin for forming the reinforcing layer, and adopts the inner core system to provide the first and second double reinforcements. An object of the present invention is to provide a production method capable of efficiently producing a fiber-reinforced thermoplastic resin tube having excellent adhesive strength between layers even when forming layers.

[0008]

According to a first aspect of the present invention, in a method for producing a fiber-reinforced thermoplastic resin pipe, an inner core is provided in a die of an extruder so as to project from the die in an extruding direction.
In the inner core, in a state where the temperature of the resin forming the two-layer pipe is maintained within a temperature range of the softening temperature or more and less than the melting temperature,
A fiber characterized by introducing the two-layer pipe and winding a tape-shaped or string-shaped fiber composite at a position outside the inner core at a temperature lower than a melting temperature of a resin held in the fiber composite. The essence is a method for producing a reinforced thermoplastic resin tube, and by doing so, it is possible to prevent the fibers from rising due to the melting of the matrix resin of each reinforced layer, and to prevent the thermoplastic resin inner layer of the inner core from forming. The main point is to ensure smooth sliding.

According to the invention described in claim 2, the obtained 3
The method for producing a fiber-reinforced thermoplastic resin pipe according to claim 1, wherein at least an interface between the first reinforcing layer and the second reinforcing layer of the layered tube is reheated to a melting temperature or higher. The main point is to increase the adhesive strength between the layers by doing so.

In the invention according to claim 1 or 2, the continuous reinforcing fibers used in the sheet-shaped, tape-shaped or string-shaped fiber composite are roving-shaped or strand-shaped composed of continuous filaments having a diameter of 1 to several tens of μm. What is used.

Concretely, inorganic fibers such as glass fiber, carbon fiber, silicon / titanium / carbon fiber, boron fiber, fine metal fiber, aramid fiber, vinylon fiber, liquid crystal polymer fiber, polyester fiber, polyamide fiber, etc. All of the continuous fibers that can be used as reinforcing fibers for synthetic resins, such as organic fibers, can be mentioned.

The fiber composites used for forming the first and second reinforcing layers may use the same type of fibers or different types of fibers. Further, the continuous fiber is preferably one in which the thermoplastic resin is sufficiently impregnated and retained between the filaments, and it is preferable that the continuous fiber forms a reinforcing layer. It is preferable from the viewpoint of enhancing watertightness and adhesion between the continuous fiber and the thermoplastic resin. From this viewpoint, the thermoplastic resin is preliminarily impregnated between the filaments before the step of producing the fiber composite, which will be described later. It is preferable to perform surface treatment such as.

In the invention according to claim 1 or 2, the fiber composite is held by a continuous resin filament being adhered or impregnated with a thermoplastic resin, and held by heating, pressurizing or the like into a sheet, tape or string. In this composite, continuous fibers are arranged substantially parallel to the longitudinal direction thereof.

The width and thickness of this fiber composite are not particularly limited, but when using a string-shaped fiber composite, a diameter of 0.5 to 5 mm is suitable, and a tape-shaped one. In the case of using, those having a thickness of about 0.1 to 10 mm are suitable.

The amount of fibers in the fiber composite is 5 to 70% by volume.
If it is less than 5% by volume, a sufficient reinforcing effect cannot be obtained. On the contrary, if it exceeds 70% by volume, the thermoplastic resin is not sufficiently impregnated and the reinforcing effect is rather reduced. Also,
The continuous fibers in the tape-shaped fiber composite need to be arranged substantially parallel to the longitudinal direction thereof as described above, but in addition to that, the finite fibers arranged in the intersecting direction such as the direction orthogonal to the continuous fibers are also available. It may include a length of fiber.

In the invention of claim 1 or 2, the thermoplastic resin to be retained in the continuous reinforcing fiber is not particularly limited, and examples thereof include polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, polystyrene,
Examples thereof include polyamide, polycarbonate, polyphenylene sulfide, polysulfone, and polyether / etherketone. These thermoplastic resins may be used alone or as a mixture of two or more depending on the purpose of use of the tube. Further, additives such as heat stabilizers, plasticizers, lubricants, antioxidants, ultraviolet absorbers, pigments, reinforcing fibers, inorganic fillers, processing aids, modifiers, etc. may be added.

The thermoplastic resin for the inner layer does not have to be the same as the thermoplastic resin retained by the continuous reinforcing fibers in the fiber composite, and it can be extruded into a tubular shape and has a fusible property. If it is good, it can be adopted.

However, the thermoplastic resin in the fiber composite for the second reinforcing layer is more fused to the thermoplastic resin used in the first reinforcing layer which is in direct contact than the fusion property to the thermoplastic resin for the inner layer. You should emphasize the wearability,
The larger one should be selected and used, and by doing so, the interlayer adhesion between the first reinforcing layer and the second reinforcing layer becomes higher, and an excellent fiber-reinforced thermoplastic resin pipe can be obtained.

The term "fusing property" as used herein means that both resins are heated to a molten state and then pressure-bonded, and after cooling, the fused interface is not easily broken. As a method for holding the thermoplastic resin in the continuous reinforcing fiber, all known methods can be adopted, and, for example, (1) the continuous reinforcing fiber is passed through a fluidized bed of powdered thermoplastic resin, A method in which a powdery thermoplastic resin is adhered to a fiber filament and then heated to integrate the fiber and the resin, (2) continuous reinforcing fibers are passed through an emulsion of the thermoplastic resin to form the thermoplastic resin between the filaments. A method of impregnating the same with the resin and then heating it to a temperature higher than the melting temperature to integrate the fibers and the resin, or allowing the resin to pass through the emulsion and drying once, and then heating to a temperature higher than the melting temperature to integrate them. 3) In the case of a resin having a low melt viscosity, a method of immersing a bundle of continuous reinforcing fibers in a tank filled with the molten resin to impregnate the resin,
(4) A method in which a film-like thermoplastic resin is laminated on continuous reinforcing fibers and heated and pressed is adopted.

Further, in the invention according to claim 1 or 2, after forming the three-layer pipe, it is optional to further provide an outer layer of a thermoplastic resin on the upper layer, and the resin used for the outer layer is not particularly limited. Although all thermoplastic resins can be used, it is preferable to use a resin having a good fusion property with the resin held in the second reinforcing layer.

In the invention according to claim 1 or 2, as a method of maintaining the temperature of the two-layer pipe at the time of introduction into the inner core within a temperature range from the softening temperature to less than the melting temperature, a thin material is attached to the tip of the mold. A support material consisting of is attached to the support material, and an inner core is attached to the support material to allow a distance to enter the inner core. A gas such as temperature-controlled air is ejected from this support material to cool it from the inner surface. Method (Note that this method is likely to be over-cooled and may be difficult to introduce into the inner core.) A gas such as air whose temperature is controlled outside the two-layer tube There is a method of jetting and cooling.

In the second aspect of the invention, as a method for reheating the three-layer tube, it may be heated by directly applying hot air or the like from the surroundings, but when it is overheated, the reinforcing fibers may come out again. It is preferable to employ an internal heating method utilizing electromagnetic waves, such as a far infrared heating device.

[0023]

According to the first aspect of the present invention, the innermost layer of the thermoplastic resin is used as the innermost layer, and the continuous fiber is formed on the outer side of the inner layer, and the continuous fiber is formed on the outer side of the first reinforcing layer. In a method for producing a composite pipe formed by forming a second reinforcing layer wound in the circumferential direction of the pipe, an inner core is provided in a die of an extruder in an extrusion direction from the die, and two layers are formed. Since the temperature of the pipe was introduced into the tube while maintaining it in the temperature range of the softening temperature or more and less than the melting temperature, the thermoplastic resin inner layer did not adhere to the inner core, and the thermoplastic resin inner layer The first reinforcing layer is firmly fused. Furthermore, the winding of the fiber composite for forming the second reinforcing layer does not cause the fibers in the first reinforcing layer of the two-layer tube to stand out.

Further, the fiber composite is wound at a position corresponding to the inner core, that is, at a position outside the inner core, and the matrix resin in the fiber composite is wound at a temperature lower than its melting temperature. Therefore, even if the tightening force due to the winding works, it is possible not only to prevent the two-layer tube from being deformed, but also to prevent the fibers in the first or second reinforcing layer from protruding.

Since the reinforcing fibers are arranged in the axial direction in the first reinforcing layer, when a continuously molded three-layer pipe is taken in, the pipe is deformed by a tensile force applied to the pipe. Can be kept to a minimum.

The invention according to claim 2 also provides the obtained 3
Since the interface between at least the first reinforcing layer and the second reinforcing layer of the layered tube is heated to the melting temperature or higher, fusion between the reinforcing layers of the composite tube can be performed more reliably.

[0027]

Embodiment 1 First, an apparatus used for carrying out the present invention will be described with reference to the drawings. The drawings explain the invention of claim 1 and the invention of claim 2 together. In the following description, the term "front" means the rightward direction in FIG.

The apparatus for producing a fiber-reinforced thermoplastic resin pipe shown in FIGS. 1 and 2 is a sheet-like fiber composite A1 for a first reinforcing layer.
A rewinding roll 1 in which is wound, and a thermoplastic resin extruder for an inner layer, which is arranged in front of the rewinding roll 1 and has a tip portion bent forward at a right angle and an outer peripheral portion of which is an inner mold 2 having a circular cross section. The first extruder 3, the heating means 4 arranged on one side of the rear part thereof, the pair of drum-shaped shaping rolls 5 sandwiching the inner mold 2 from both sides, and the first extruder 3 Has a core 6 which is provided on the shaft center of the tip end of the and which protrudes forward of the inner mold 2.

Further, the core 6 has a base portion 6a having a diameter-enlarged portion which becomes thicker in an inverted conical shape in the vicinity of the front end from the rear to the front, and a small diameter which is protruded from the end face of the mold and is provided in front thereof. Support member 6b and an inner core 6c which is provided integrally with the support member 6b and which has four large diameter portions sandwiching three small diameter portions therebetween, and also has a base portion 6a and an inner core 6c. The outer diameter of the large-diameter portion is substantially the same as the inner diameter of the thermoplastic resin inner layer. Also, these bases 6a
The support member 6b and the inner core 6c are integrally formed by bolt-nut coupling.

The inside of the core 6 is hollow, and the compressed air sent from the compressed air generator 23 to the rear of the inner mold 2 through the conduit is supplied to the support member 6b. It is possible to maintain the pipe diameter by ejecting from the ejection hole 22 and maintaining the pressure applied to the inner layer of the thermoplastic resin constant, and to facilitate introduction into the inner core 6c.

In the present manufacturing apparatus, an outer die 7 is further installed so that the tip surface of the inner die 2 is aligned with the inner die 2 from an outer position in the vicinity of the tip. Reference numeral 8 denotes a warm / cool air generator, which is also designed to blow out warm air or cold air by blowing air from an energy source having a cooling / heating function (not shown). 83, 84 positioned in front of the two-layer pipe are blown out with a wind having a temperature that maintains the softening temperature and lower than the melting temperature.
The two units are designed to blow air for cooling the temperature of the matrix resin forming the first reinforcing layer A3 of the two-layer pipe to a temperature lower than the softening temperature of the resin.

9 is a tape-shaped fiber composite C1 for the second reinforcing layer
Heating means comprising an infrared generator for heating to a temperature below the melting temperature of the matrix resin, 10 is a winding machine for the tape-shaped fiber composite C1, and 11 is a furnace provided with a far infrared generator. Means, 12 is a second extruder for extruding the outer layer thermoplastic resin, 13 is a coating die provided at the tip thereof, 14 is a sizing device provided in front of it, and 15 is a take-up machine.

Further, as shown in FIG. 2, both edges a of the sheet-shaped fiber composite A1 for the first reinforcing layer are overlapped between the inner mold 2 and the pair of drum-shaped shaping rolls 5. A gap corresponding to the thickness of the tubular bodies A2 to be molded together is provided. Base 6
Between the a and the tubular body A2, the thermoplastic resin inner layer B2 formed by the molten resin B1 extruded from the extruder 3.
A gap corresponding to the thickness of is provided. That is, the base 6a has an outer diameter that is substantially the same as the inner diameter of the thermoplastic resin inner layer B3.

Incidentally, in FIG. 3, since the tubular body A2 is formed from the sheet-shaped fiber composite A1, instead of using the pair of shaping rolls 5, the shaping die 24 corresponds to the pair of shaping rolls 5. A modified example provided at a position to be shown is shown.

The sheet-shaped fiber composite A1 and the tape-shaped fiber composite C1 are manufactured using the fluidized bed apparatus 16 shown in FIG. The bottom of the fluidized bed apparatus 16 is formed of a perforated plate 17, and a gas G such as air or nitrogen sent from a gas supply passage is passed upward from below the perforated plate 17 through many holes thereof. Is made to squirt. As a result, the powdered thermoplastic resin put in the tank of the fluidized bed apparatus 16 is fluidized by the jetted gas G, and the fluidized bed R is formed.
A guide roll 18 for guiding the continuous reinforcing fibers F1 is provided in the tank of the fluidized bed apparatus 16 and at the upper ends of the front and rear walls thereof.

Using the fluidized bed apparatus 16 described above, 10 bundles of continuous reinforcing fibers F1 composed of a large number of continuous filaments were unwound from a rewinding roll 19 by a winding roll 20 while preventing twisting, and powdered. The fluidized bed R of the body-like thermoplastic resin is passed through to adhere the powdery thermoplastic resin to each filament of the bundle-like reinforcing fibers F1. In the case of this example, as the powdery thermoplastic resin, a vinyl acetate-vinyl chloride copolymer (vinyl acetate amount 8%, average particle size =
250 μm) and the reinforcing fiber has a diameter of 23 μm.
Roving glass fiber (44
00tex) was used.

Further, the powdery thermoplastic resin adhesion reinforcing fiber F2 is passed through a pair of heating rolls 21 heated to about 180 ° C., heated and pressed to melt the thermoplastic resin and strengthen it. A sheet-shaped fiber composite body F3 having a thickness of 0.6 mm was obtained by integrating it with the fiber, and this was taken up as a winding roll 20.
Rolled up. The volume ratio of the thermoplastic resin and the reinforcing fiber of the sheet-shaped fiber composite F3 is 75% of the thermoplastic resin,
The reinforcing fiber was 25%.

The above-mentioned sheet-shaped fiber composite F3 was cut, and the continuous reinforcing fibers were arranged in the longitudinal direction to have a width of 91 mm and a thickness of 0.6.
A sheet-shaped fiber composite A1 having a width of 23.5 mm and a thickness of 0.6 mm in which continuous reinforcing fibers were arranged in the lengthwise direction were obtained.

The sheet-like fiber composite A1 for the first reinforcing layer produced as described above is transferred to the rewinding roll 1 shown in FIG. 1, and while being rewound, hot air is blown by the heating means 4 consisting of a hot air generator. Then, both edges a of the sheet-shaped fiber composite A1 are overlapped with each other, and a tubular body A2 having an outer diameter of 29 mm and a thickness of 0.6 mm is formed by the shaping roll 5 and the inner mold 2.
Was continuously molded.

Next, the formed tubular body A2 is transferred to the inner die 2
And, it is introduced into the annular gap between the base 6a and the outer mold 7. In this case, the inner mold 2, the base 6a and the outer mold 7 are 20
It was heated to 0 ° C., where the polymerized edges a, a were fused.

While advancing the tubular body A2 having polymerized both edges a, the thermoplastic resin B for the inner layer is advanced along the inner surface of the tubular body A2.
1 is extruded in a molten state to laminate a molten resin layer B2,
By forming a thermoplastic resin inner layer B3 having a thickness of 1.5 mm and having a first reinforcing layer A3 in which reinforcing fibers are arranged in the longitudinal direction of the pipe, a two-layer pipe having an outer diameter of 29 mm is formed. As the thermoplastic resin B1 for the inner layer, a polyvinyl chloride resin (degree of polymerization = 10
00) was used.

While advancing the two-layer pipe as it is, the two-layer pipe is guided to the inner core 6C having substantially the same outside diameter (large diameter part = 25.0 mm) as the inside, while the two-layer pipe is
Before reaching the inner core 6C, the warm / cool air generator 81,
82, the resin temperature was adjusted to a temperature not lower than the softening temperature and not higher than the melting temperature of the matrix resin constituting the first reinforcing layer A3 of the two-layer pipe. In this case, by setting the softening temperature or higher, the first reinforcing layer A3 and the thermoplastic resin inner layer B3 are firmly fused and integrated, and further, in combination with the high tensile strength of the reinforcing fiber, The two-layer pipe can be continuously drawn onto the inner core 6C without being stretched and even when a strong drawing force is exerted by the drawing machine 15. On the other hand, at the softening temperature or lower, the two-layer pipe is made into the inner core 6 having an outer diameter of 25.0 mm.
It is difficult to introduce it into C, and above the melting temperature, the thermoplastic resin inner layer B3 adheres to the inner core 6C, making it difficult to take it back.

The two-layer pipe was sized on the inner core 6c while controlling the inner surface thereof. The two-layer pipe is cooling air generated by the pressure air generator 23 while passing through the inner core 6c and ejected from an inner pipe (not shown) provided inside the support member 6b and the inner core 6c. And cold air generator 8
The resin temperature was adjusted below the softening temperature by cold air from 3,84.

As described above, when the inside of the inner core is cooled by the refrigerant and the temperature of the two-layer pipe is lower than the softening temperature of the matrix resin of the first reinforcing layer, the inner layer of the thermoplastic resin is prevented from adhering to the inner core, and This is preferable in that it is possible to more reliably prevent deformation of the layered tube and to facilitate reheating of the three-layered tube in the next step.

Furthermore, the tape-shaped fiber composite C1 for the second reinforcing layer is wound around the outer periphery of the two-layer pipe on the core 6c by the winding machine 10. At this time, while being heated by the heating means 9 to the softening temperature of the matrix resin of the tape-shaped fiber-fiber composite C1 or higher (for example, 160 ° C.), the tape-shaped fiber-fiber composite C1 is spirally wound at an angle of 75 ° C. with respect to the axial direction. First
A three-layer pipe was obtained by closely contacting the reinforcing layer A3 and forming the second reinforcing layer C2 in which the reinforcing fibers were arranged in the circumferential direction on the outer surface of the first reinforcing layer A3.

Next, the three-layer tube is introduced into the heating means 11 consisting of a heating furnace provided with a far infrared heater, and the three-layer tube is at least the interface between the first reinforced layer A3 and the second reinforced layer C2. The resin was heated until the resin temperature reached the melting temperature (200 ° C.), and both reinforcing layers were fused and integrated. In this embodiment, the far-infrared heater heats the three-layer tube, but the heating means is not limited to this, and any heating means capable of achieving the intended heating purpose may be used as described above.

Subsequently, the three-layer pipe is introduced into the coating mold 13, and the thermoplastic resin for the outer layer melt-plasticized by the second extruder 12 is extruded onto the outer periphery of the second reinforced layer C2 to coat it, and the thickness After molding a 1 mm thermoplastic resin outer layer D,
Cooling sizing is performed by the sizing device 14 to form a four-layer pipe. Polyvinyl chloride resin (average degree of polymerization = 1000) was used as the thermoplastic resin for the outer layer.

The above series of steps are carried out while being taken by the take-up machine 15, and a fiber-reinforced thermoplastic resin pipe E having an inner diameter of 25.0 mm and an outer diameter of 32.2 mm made of a four-layer composite pipe as shown in FIG. 5 is continuously formed. Molded into a

Instead of providing the heating means 4, a heater may be incorporated in the pair of shaping rolls 5 and the heating may be performed at a temperature higher than the softening temperature of the sheet-shaped fiber composite A1. The position of the heating means 4 is not limited to the illustrated position, and it may be omitted in some cases.

In addition, when the tape-shaped fiber composite C1 for the second reinforcing layer is wound around the first reinforcing layer A3 and tightly adhered thereto, a roll or a leaf spring can be used in addition to the method of winding while maintaining a constant tension. For example, it may be wound under pressure.

A water tank is generally used as the cooling device 14 for cooling sizing, but the cooling device is not limited to this.

[0052]

According to the invention of claim 1, the innermost layer of the thermoplastic resin is used as the innermost layer, and the first reinforcing layer in which continuous fibers are arranged in the longitudinal direction of the pipe is formed on the outer side of the inner layer. In a method for producing a composite pipe, in which fibers form a second reinforcing layer arranged in the circumferential direction of the pipe, a die of an extruder is provided with an inner core in the extrusion direction from the die,
Since the temperature of the two-layer pipe is introduced into the temperature range maintained above the softening temperature and below the melting temperature,
The inner layer of thermoplastic resin does not adhere to the inner core, and the inner layer of thermoplastic resin and the first reinforcing layer are firmly fused.

Therefore, the inner core and the thermoplastic resin inner layer slide smoothly, and the desired take-up speed can be maintained, and the production speed can be increased and the productivity can be improved. ..

Furthermore, the winding of the fiber composite for forming the second reinforcing layer does not cause the fibers in the first reinforcing layer of the two-layer tube to stand out. Further, the fiber composite is wound at a position corresponding to the inner core, that is, at a position outside the inner core, and the matrix resin in the fiber composite is wound at a temperature lower than its melting temperature. Therefore, even if the tightening force by the winding works, not only the deformation of the two-layer tube can be prevented, but also the fibers in the first or second reinforcing layer do not come out.

Therefore, as the resin forming the inner and outer layers and the resin held by the reinforcing fibers, all of the thermoplastic resins are used, and there is a resin having excellent interfacial strength between the first and second reinforcing layers. Even if it is obtained and used for a long period of time under severe temperature conditions such as high-temperature water, interfacial peeling hardly occurs and the pipe lasts a long time.

Since the reinforcing fibers are arranged in the axial direction in the first reinforcing layer, when a continuously molded three-layer pipe is drawn, the pipe deformation caused by the tensile force applied to the pipe is also generated. Can be kept to a minimum.

Therefore, it is possible to obtain a fiber-reinforced thermoplastic resin tube having excellent dimensional accuracy. Further, since the reinforcing fibers are arranged in both the longitudinal direction and the circumferential direction of the tube, it is possible to obtain a composite tube having a pressure resistance and an impact resistance comparable to those of the composite tube using the thermosetting resin.

According to the second aspect of the present invention, at least the interface between the first reinforcing layer and the second reinforcing layer of the obtained three-layer tube is heated to a temperature equal to or higher than its melting temperature, so that the composite tube of the composite tube can be more surely heated. Since fusion between the reinforcing fiber layers is performed, the occurrence of interfacial peeling can be more completely prevented, and a fiber-reinforced thermoplastic resin tube having excellent durability can be obtained.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view showing an example of a manufacturing apparatus used for carrying out the present invention.

2 is a cross-sectional view taken along the line II-II of FIG. 1 and viewed in the direction of the arrow, and FIG. 2B is also the same as FIG.
FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 3 is a partially cutaway plan view showing a modified example of a tubular body molded portion.

FIG. 4 is a vertical cross-sectional view showing an example of an apparatus for producing a sheet-shaped fiber composite body F3 including a fluidized bed apparatus.

FIG. 5 is a partially cutaway perspective view of a fiber reinforced thermoplastic resin tube obtained by the apparatus shown in FIG. 1 of the present invention.

[Explanation of symbols]

 A1 sheet-shaped fiber composite A2 tubular body A3 first reinforcing layer B1 thermoplastic resin for inner layer B2 molten resin layer B3 thermoplastic resin inner layer C1 tape-shaped fiber composite C2 second reinforcing layer D thermoplastic resin outer layer F1 continuous reinforcing fiber F2 Powdery thermoplastic resin adhesion reinforcing fiber F3 Sheet fiber composite P1 Fiber reinforced thermoplastic resin tube P2 Fiber reinforced thermoplastic resin tube P3 Fiber reinforced thermoplastic resin tube P4 Fiber reinforced thermoplastic resin tube R Fluidized bed 2 Inner mold 3 First Extruder 4 Heating Means 6 Core 6a Base 6b Support Material (Part) 6c Inner Core (Projection) 7 Outer Mold 8 Cooling Means 9 Heating Means 10 Winding Machine 11 Heating Means

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Claims (2)

[Claims] 1. A step of continuously forming a tubular body from a sheet-shaped fiber composite in which a thermoplastic resin is held by continuous reinforcing fibers arranged in a longitudinal direction, and a step of advancing the tubular body along its inner surface. A step of forming a two-layer pipe by forming a thermoplastic resin inner layer having a first reinforcing layer by laminating a thermoplastic resin for an inner layer in a molten state from an extruder and laminating the two layers while advancing the two-layer pipe as it is. A tape-shaped or string-shaped fiber composite, in which a thermoplastic resin is held by continuous reinforcing fibers arranged in the longitudinal direction, is wound around the outer periphery of the first reinforcing layer in a spiral shape, and the second reinforcing layer is formed on the outer surface of the first reinforcing layer. In a method for producing a fiber-reinforced thermoplastic resin tube, which has at least a step of forming a three-layer tube by forming a reinforced layer, a mold of an extruder is provided with an inner core protruding from a mold in a direction of extrusion. , To the core of this, before The two-layer pipe is introduced while maintaining the temperature of the resin constituting the two-layer pipe within a temperature range from the softening temperature to less than the melting temperature, and a tape-shaped or string-shaped fiber composite is formed at a position outside the inner core. A method for producing a fiber-reinforced thermoplastic resin tube, which comprises winding at a temperature lower than a melting temperature of a resin held in the fiber composite. 2. The fiber-reinforced thermoplastic resin pipe according to claim 1, wherein at least an interface between the first reinforcing layer and the second reinforcing layer of the obtained three-layer pipe is reheated to a melting temperature or higher. Production method.