JPH0911355A - Manufacture of fiber reinforced thermoplastic resin composite tube - Google Patents

Abstract

PURPOSE: To provide a manufacturing method for a fiber reinforced thermoplastic resin composite tube in which the fusion bonding force of a multilayer tubular body is stabilized having quality without unevenness. CONSTITUTION: A manufacturing method comprises the process of forming a core material P for cooling and solidifying an extrusion molded thermoplastic resin tube, the process of forming an inner layer Q for an inner layer for extrusion coating thermoplastic resin of thermal expansion coefficient smaller than that of the thermoplastic resin of the core material P on the outer face of the core material P, and also the process of forming a resin layer by winding belts almost in the peripheral direction on which the thermoplastic resin of thermal expansion coefficient smaller than that of the thermal plastic resin of the core material and compatible with the thermoplastic resin of the inner layer Q is retained, on continuous fiber disposed in the longitudinal direction and forming a multilayer tubular body T on the outer face of the inner layer Q. Also the process of heating up the multilayer tubular body T to the thermal expansion temperature - thermal decomposition temperature of the thermoplastic resin of the core material P and also the temperature of the Vicat softening point - thermal decomposition temperature of the thermoplastic resin of the resin layer and then cooling and solidifying the multilayer tubular body and the process of drawing the core material P out of the inside of the solidified multilayer tubular body T are included in the manufacturing method.

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 comprising a thermoplastic resin and reinforcing fibers.

[0002]

2. Description of the Related Art A fiber-reinforced resin composite pipe having a layer made of a thermoplastic resin on its inner surface is
It is not rusted and has excellent strength, and is widely used as pipes for transporting fluids such as water and gas, pipes used for electric wiring, structural members and the like.

Conventionally, in a fiber-reinforced composite pipe, a reinforcing fiber impregnated with a liquid thermosetting resin is wound around a mandrel on the outer surface of a thermoplastic resin pipe as an inner layer, and the mandrel is cured after the thermosetting resin is cured. It is manufactured by a drawing method (filament winding method) (for example, see Japanese Patent Publication No. 62-773).

This type of fiber-reinforced resin composite pipe has a weak adhesive force at the interface, and when the fiber-reinforced resin composite pipe is used under conditions of repeated heat and cold, due to the difference in thermal expansion coefficient between the inner layer and the fiber-reinforced resin layer, There is a problem of interfacial peeling.

In order to solve this problem, for example, as described in JP-A-6-218841, a thermoplastic resin is used as a resin for forming a fiber reinforced resin layer, and a thermoplastic resin layer as an inner layer and a fiber reinforced resin are used. A method for producing a fiber-reinforced resin composite pipe having a strong fusion force with a resin layer is known.

According to this method, a reinforcing layer made of a fiber reinforced resin composite is wound around the outer surface of a pipe made of a thermoplastic resin as an inner layer and laminated to form a multilayer tubular body, and the multilayer tubular body is fused. , The inner atmosphere of the multi-layer tubular body, the depressurization of the outer atmosphere, or both, the multi-layer tubular body is exposed to the atmosphere and heated to strengthen the tube made of the thermoplastic resin and the fiber-reinforced resin composite. A method of fusion bonding and integration has been proposed.

[0007]

However, in the case of this method, the portion where the multilayer tubular body is fused under pressure or reduced pressure is supported by a support member extending from the extruder side. Since it is necessary to continuously seal with a rubber stopper etc.,
It may cause troubles when starting up continuous production,
Further, since the sealing degree due to the rubber plug varies due to a slight change in the inner diameter of the multilayer tubular body, the fusion force may vary.
There is a problem that the rubber plug is easily deteriorated and is promoted.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a method for producing a fiber-reinforced thermoplastic resin composite pipe in which the fusion bonding force of the multilayer tubular body is stable and the quality is uniform. It was made.

[0009]

According to the present invention, there is provided a step of forming a core material by once cooling and solidifying an extruded thermoplastic resin tube, and a thermal expansion on the outer surface of the core material as compared with the thermoplastic resin of the core material. A step of forming an inner layer by extrusion-coating a thermoplastic resin that has a low rate and is incompatible with the thermoplastic resin, and a continuous fiber arranged in the longitudinal direction on the outer surface of the inner layer than the thermoplastic resin of the core material. A step of forming a fiber-reinforced thermoplastic resin layer into a multilayer tubular body by winding a belt-shaped body having a thermoplastic resin having a small thermal expansion coefficient and compatibility with a thermoplastic resin of an inner layer and winding the belt-shaped body in a substantially circumferential direction, The tubular body is heated to a temperature from the thermal expansion temperature of the thermoplastic resin of the core material to the thermal decomposition temperature and the Vicat softening point of the thermoplastic resin of the fiber-reinforced thermoplastic resin layer to the thermal decomposition temperature, and then cooled. The process of solidification and the core material from the solidified multilayer tubular body A method for producing a fiber-reinforced thermoplastic resin composite pipe comprising the step of withdrawing.

In the present invention, as the thermoplastic resin of the inner layer, one having a smaller coefficient of thermal expansion than the thermoplastic resin of the core material and being incompatible with the thermoplastic resin is used. The coefficient of thermal expansion of the thermoplastic resin of the inner layer is preferably 0.9 times or less, and more preferably 0.7 times or less the coefficient of thermal expansion of the thermoplastic resin of the core material. In addition, that the thermoplastic resin of the inner layer is not compatible with the thermoplastic resin of the core material as used herein means that the interface is easily peeled off after cooling even when both thermoplastic resins are brought into close contact with each other by heating. The core material is considered to be reused after peeling, and it is preferable to use a thermoplastic resin that is easy to recycle.

As a combination of the thermoplastic resin of the inner layer and the thermoplastic resin of the core material, for example, in the thermoplastic resin of the inner layer, polyvinyl chloride, chlorinated polyvinyl chloride, etc. Examples include polyethylene, polypropylene, polytetrafluoroethylene, and the like.

In the present invention, as the thermoplastic resin of the fiber reinforced thermoplastic resin layer, one having a smaller coefficient of thermal expansion than the thermoplastic resin of the core material and having compatibility with the thermoplastic resin of the inner layer is used. . The thermal expansion coefficient of the thermoplastic resin of the fiber-reinforced thermoplastic resin layer is, like the thermoplastic resin of the inner layer, preferably 0.9 times or less of the thermal expansion coefficient of the thermoplastic resin of the core material, and 0.7 times or less. More preferable.

As the thermoplastic resin of the fiber reinforced thermoplastic resin layer, one that can be heat-sealed with the thermoplastic resin of the inner layer is used, and examples thereof include polyvinyl chloride, polyethylene, polypropylene, polyamide, polycarbonate, polyphenylene sulfide, polysulfone , Polyether ether ketone, etc., but the same kind as the thermoplastic resin of the inner layer is particularly preferably used.

The term "heat-meltable" means that both thermoplastic resins are heated to a molten state and then pressure-bonded.
It means that the fused interface is not easily broken after cooling.
If necessary, a thermal stabilizer, a plasticizer, a lubricant, an antioxidant, an ultraviolet absorber, a pigment, an inorganic filler, a processing aid, a modifier, etc. may be added to each thermoplastic resin. .

In the present invention, the form of the strip is as follows.
A tape shape or a string shape is preferable because it is usually easy to wind. In the present invention, as the material of the continuous fibers forming the strip, for example, glass fibers, inorganic fibers such as carbon fibers,
Examples include organic fibers such as aramid fiber, vinylon fiber, and polyester fiber. Examples of the form of continuous fibers include monofilaments, rovings, strands, crosses, nets, and nets.

Examples of the form of winding the strip-like body include a tape-like form and a string-like form. The width, thickness, diameter and the like of the strip-like form vary depending on the size of the composite pipe to be formed, the required performance and the like. . In the case of a tape, its width is preferably about 1/30 to 1 times the inner diameter of the composite pipe to be molded, more preferably about 1/10 to 2/3, and its thickness is not particularly limited. It is preferably about 1 to 5 mm. In the case of a string, the diameter is preferably about 1 to 10 mm.

The thickness of the monofilament constituting the continuous fiber is 1 to 100 μm because if the fiber is too thick, a part where the thermoplastic resin is not held is generated, and if it is too thin, it may be cut.
m is preferable, and 3 to 50 μm is more preferable.

If the amount of continuous fibers in the strip is too large, the amount of the thermoplastic resin held between the fibers will be small, and if it is too small, the reinforcing effect will not occur, so 3 to 70% by weight is preferable, and 10 to 10% by weight is preferable. 50% by weight is more preferable.

As a method for manufacturing the strip, for example, the following method can be adopted. Continuous fibers such as roving, strand, cloth, net and net made up of many filaments are sequentially passed through a fluidized bed of powdered thermoplastic resin, and the powdered thermoplastic resin is adhered between the fibers. After that, heating is performed to integrate the continuous fiber and the thermoplastic resin.

Continuous fibers similar to the above are passed through an emulsion of a thermoplastic resin to impregnate the emulsion with the fibers, and then heated to a temperature equal to or higher than the melting temperature of the thermoplastic resin to integrate the continuous fibers and the thermoplastic resin. How to make.

In the case of a thermoplastic resin having a low melt viscosity, the same continuous fibers as described above are dipped and passed through a tank filled with the molten thermoplastic resin so that the thermoplastic resin is adhered and solidified between the fibers. How to find a monkey. A method of laminating a thermoplastic resin film on the same continuous fibers as above and thermocompression bonding.

In the present invention, as a method for forming the core material by once cooling and solidifying the extruded thermoplastic resin tube,
A conventionally known extrusion molding method can be appropriately adopted. In the present invention, as a method of forming the inner layer by extrusion coating the outer surface of the core material with a thermoplastic resin, a conventionally known coating method using a crosshead die or the like can be appropriately adopted.

In the present invention, a method for forming a fiber-reinforced thermoplastic resin layer by winding a strip-shaped body in which continuous fibers arranged in the longitudinal direction and a thermoplastic resin are held on the outer surface of the inner layer is wound in a substantially circumferential direction. A conventionally known filament winding method, a method using a braiding machine, or the like can be appropriately adopted.

In the present invention, as a method for heating the multilayer tubular body, conventionally known heating means such as hot air, a heating furnace and infrared rays can be appropriately adopted. The heating temperature of the multilayer tubular body is a temperature of the thermal expansion temperature to the thermal decomposition temperature of the thermoplastic resin of the core material, and the Vicat softening point of the thermoplastic resin of the fiber-reinforced thermoplastic resin layer to the thermal decomposition temperature. is there.

When the heating temperature of the thermoplastic resin of the core material exceeds the thermal decomposition temperature, it may affect the inner layer resin and the like coated thereon and impair its performance. If it is lower than the thermal expansion temperature, the core material Cannot be thermally expanded, and the multi-layer tubular body cannot be fused. This heating temperature is from the Vicat softening point of the thermoplastic resin of the core material −50 ° C. to the Vicat softening point +5.
Temperatures in the range of 0 ° C are preferred.

Here, the Vicat softening point is JIS K
It is measured according to 7206. The Vicat softening temperature of the thermoplastic resin of the fiber-reinforced thermoplastic resin layer is, for example, about 65 to 85 ° C. for polyvinyl chloride and about 95 to 120 ° C. for chlorinated polyvinyl chloride.

By heating the multilayer tubular body at the above temperature, the thermoplastic resin of the core material is heated to the temperature of the thermal expansion temperature to the thermal decomposition temperature, and the Vicat softening of the thermoplastic resin of the fiber reinforced thermoplastic resin layer is performed. It is heated to a temperature between point and thermal decomposition temperature.

Since the coefficient of thermal expansion of the thermoplastic resin of the inner layer and the fiber-reinforced thermoplastic resin layer is smaller than the coefficient of thermal expansion of the thermoplastic resin of the core material, the thermal expansion of the inner layer and the fiber-reinforced thermoplastic resin layer The thermal expansion of the core material is larger than that of the core material, and the thermal expansion of the core material presses the inner layer onto the fiber-reinforced thermoplastic resin layer.

As a result, the interface between the inner layer and the fiber-reinforced thermoplastic resin layer is compatible with both thermoplastic resins, so that after cooling it is heat-fused so that the fused interface does not break easily. . However, the interface between the core material and the inner layer is not compatible with both thermoplastic resins, and the coefficient of thermal expansion of the thermoplastic resin of the core material is the coefficient of thermal expansion of the thermoplastic resin of the inner layer and the fiber-reinforced thermoplastic resin layer. Since it is larger, the core material is reduced in diameter by heat shrinkage and easily peeled off after cooling. Therefore, the core material can be easily extracted from the multilayer tubular body to obtain a fiber-reinforced thermoplastic resin composite pipe.

An example of the present invention will be described below with reference to the drawings. FIG. 1 is a front view for explaining a process of an example of the present invention together with a manufacturing apparatus, FIG. 2 is a perspective view showing an intermediately obtained multilayer tubular body, and FIG. 3 is a finally obtained fiber-reinforced thermoplastic resin composite pipe. FIG.

First, the manufacturing apparatus will be described. The manufacturing apparatus includes an extruder 11 for extruding a thermoplastic resin as a core material,
An extrusion die 12 attached to the tip of the extruder 11, a first sizing device 13, a crosshead die 15 for extruding an inner layer thermoplastic resin from the extruder 14 and covering the outer surface of the core material, and a crosshead. Rewinding rolls 16 and 17 to which the sheet-shaped strips A1 or A2 arranged above and below the die 15 are mounted, and winding devices 18 and 19 around which the tape-shaped strips B1 or B2 are wound, The heating furnace 20, the second sizing device 21, the take-up machine 22, and the cutting machine 23 are sequentially arranged.

Next, the steps of an example of the present invention using this manufacturing apparatus will be described. The thermoplastic resin of the core material is kneaded in the extruder 11 and extruded in a molten state into a tubular shape from the extrusion die 12, and this is passed through the first sizing device 13, and the cooling water is passed inside the first sizing device 13. While performing cooling, the tubular core material P is continuously formed by cooling and solidifying. This core material P is introduced into the crosshead die 15, and the outer surface of the core material P is kneaded with the thermoplastic resin of the inner layer in the extruder 14 and extruded in a molten state to cover the inner layer Q.

Subsequently, on the downstream side of the crosshead die 15, continuous fibers are axially formed in two sheet-shaped strips A1 and A2 from above and below the outer surface of the inner layer Q covering the outer surface of the core material P. Along the outer surface of the inner layer Q, the intermediate layer R
Tape-shaped strips B1 and B2 in which the thermoplastic resin is held by continuous fibers arranged on the outer surface in the longitudinal direction.
Is wound in a substantially circumferential direction while applying tension by the winding devices 18 and 19 to form the outer layer S, and the intermediate layer R is formed on the outer surface of the inner layer Q.
A multi-layer tubular body T having a fiber-reinforced thermoplastic resin layer composed of the outer layer S and the outer layer S is formed.

This multilayer tubular body T is introduced into the heating furnace 20, and the temperature of the thermoplastic resin of the core material P is from the thermal expansion temperature to the thermal decomposition temperature, and the Vicat softening point of the thermoplastic resin of the fiber reinforced thermoplastic resin layer. ~ Heat to pyrolysis temperature.

This multilayer tubular body T is attached to the second sizing device 2
Cooling is carried out by passing the inside of 1. The above-mentioned series of steps is carried out while being taken by the take-up machine 22, cut to an appropriate length by the cutting machine 23, the core material P is extracted, and the fiber-reinforced thermoplastic resin composite pipe as shown in FIG. F is produced continuously. Further, the method for producing the fiber-reinforced thermoplastic resin composite pipe of the present invention may be not only the above continuous production but also a batch type production method.

FIG. 4 is a front view for explaining a process of another example of the present invention. In this case, a tape-shaped strip in which the thermoplastic resin is held by continuous fibers arranged in the longitudinal direction without laminating the sheet-shaped strips A1 and A2 on the outer surface of the inner layer Q covering the outer surface of the core material P A winding device 18 for winding bodies B3 and B4
With reference to FIG. 1, a multilayer tubular body having a fiber-reinforced thermoplastic resin layer formed by winding the fiber-reinforced thermoplastic resin layer in a substantially circumferential direction so that mutual inclination angles are opposite to each other while applying tension by 19. A fiber reinforced thermoplastic resin composite pipe is manufactured in the same manner as the process.

[0037]

The method for producing a fiber-reinforced thermoplastic resin composite pipe of the present invention comprises a step of once forming a core material by cooling and solidifying an extruded thermoplastic resin tube, and a step of forming a core material on the outer surface of the core material with a thermoplastic material. A step of forming an inner layer by extrusion-coating a thermoplastic resin having a smaller coefficient of thermal expansion than the resin and incompatible with the thermoplastic resin; and a continuous fiber arranged in the longitudinal direction on the outer surface of the inner layer. A belt-shaped body having a smaller coefficient of thermal expansion than the thermoplastic resin and having a thermoplastic resin compatible with the inner layer thermoplastic resin is wound in a substantially circumferential direction to form a fiber reinforced thermoplastic resin layer to form a multilayer tubular body. And the multilayer tubular body, the temperature of the thermal expansion temperature of the thermoplastic resin of the core material ~ the thermal decomposition temperature, the Vicat softening point of the thermoplastic resin of the fiber-reinforced thermoplastic resin layer ~ the temperature of the thermal decomposition temperature. By heating, the inner layer and fiber reinforced thermoplastic Since the thermal expansion coefficient of the thermoplastic resin of the resin layer is smaller than the coefficient of thermal expansion of the thermoplastic resin core material,
The thermal expansion of the core material is larger than the thermal expansion of the inner layer and the fiber-reinforced thermoplastic resin layer, and the thermal expansion of the core material presses the inner layer onto the fiber-reinforced thermoplastic resin layer. As a result, the interface between the inner layer and the fiber-reinforced thermoplastic resin layer is compatible with both thermoplastic resins, so that after cooling, the interface is fused by heat so that the fused interface is not easily broken. However, the interface between the core material and the inner layer is not compatible with both thermoplastic resins, and the coefficient of thermal expansion of the thermoplastic resin of the core material is the coefficient of thermal expansion of the thermoplastic resin of the inner layer and the fiber-reinforced thermoplastic resin layer. Because it is larger
After cooling, the core material shrinks in diameter due to heat shrinkage and is easily peeled off. Therefore, the core material can be easily extracted from the multilayer tubular body to obtain a fiber-reinforced thermoplastic resin composite pipe.

[0038]

The present invention will be described below with reference to examples.Example 1 (1) Production of sheet-shaped strips and tape-shaped strips Roving composed of filaments with a diameter of 23 μm
A glass fiber bundle (4,400 tex) in powder form
Polyvinyl chloride (manufactured by Tokuyama Sekisuisha, trade name "TS-1000"
R ", coefficient of linear expansion (according to ASTM 696, the same applies hereinafter):
About 7-8 x 10 ^-Five/ ° C, Vicat softening point: about 80 ° C)
It is passed through a fluidized bed to form powdery polyvinyl chloride between the fibers.
And then apply this to a pair of heating elements heated to about 200 ° C.
Distribute in the longitudinal direction by heating and pressure bonding with a heat roll.
Sheet-shaped, in which thermoplastic resin is retained in the continuous fibers
Band A1, A2 (thickness: about 0.7 mm, width: about 88 m
m) and tape-shaped strips B1, B2 (thickness: about 0.7 m
m, width: about 20 mm). Their fiber content
Was 25% by weight in each case.

(2) Production of Fiber Reinforced Thermoplastic Resin Composite Pipe A fiber reinforced thermoplastic resin composite pipe was produced according to the production process described with reference to FIG. Rewinding roll 16,1
The sheet-shaped strip A1 or A2 is attached to 7 and the winding device 1
The tape-shaped strips B1 or B2 were attached to Nos. 8 and 19.

First, polyethylene (manufactured by Mitsui Petrochemical Co.,
Product name "Hi-Zex", coefficient of linear expansion: about 10 to 13 x 1
0 ^-5 / ° C., Vicat softening point: about 110 ° C.) the extruder 11
Was extruded in a tubular shape from the extrusion die 12 in a kneaded state and a molten state, and passed through the first sizing device 13 while being water-cooled to continuously form a tubular core material P having an outer diameter of 50.2 mm.

Next, the core material P is applied to the crosshead die 15
Guided inward, polyvinyl chloride (made by Tokuyama Sekisui company, product name "TS-1000R", coefficient of linear expansion: about 7-
(8 × 10 ⁻⁵ / ° C., Vicat softening point: about 80 ° C.) was kneaded in the extruder 14 and extruded in a molten state to coat the inner layer Q having a thickness of about 2.4 mm.

Subsequently, on the downstream side of the crosshead die 15, two sheet-shaped strips A1 and A2 (thickness: 0.7 m) are formed from above and below the outer surface of the inner layer Q covering the outer surface of the core material P.
m, width: 80 mm) continuous fibers are laminated on the outer surface of the inner layer Q so as to be along the axial direction to form the intermediate layer R, and
On the outer surface of the intermediate layer R, tape-shaped strips B1 and B2 in which a thermoplastic resin is held by continuous fibers arranged in the longitudinal direction.
(Thickness: 0.7 mm, width: 20 mm) winding device 18,
A multilayer tubular body T in which a fiber-reinforced thermoplastic resin layer composed of an intermediate layer R and an outer layer S is formed on the outer surface of an inner layer Q by being wound in a substantially circumferential direction while giving tension to each other by 19 so as to have mutually opposite inclination angles. did.

This multi-layer tubular body T is introduced into the heating furnace 20, and 1
After heating to 30 ° C., it is passed through the inside of the second sizing device 21 and cooled with water, and these series of steps are carried out while being taken by the take-off machine 22, and cut by the cutting machine 23 to a length of 3 m,
A solidified multilayer tubular body T as shown in FIG. 2 was obtained. next,
The core material P was extracted from the multilayer tubular body T to obtain a fiber-reinforced thermoplastic resin composite tube F having an inner diameter of about 51 mm and an outer diameter of about 60 mm as shown in FIG.

Example 2 (1) Production of tape-shaped strip Chlorinated polyvinyl chloride as a thermoplastic resin (trade name "HA-52K" manufactured by Tokuyama Sekisui Co., Ltd., linear expansion coefficient: 7 to 8 x 10)
^-5 / ° C., Vicat softening point: about 115 ° C.) The same as in Example 1 except that the thickness was 0.7 mm and the width was 1
5 mm, tape-shaped band B having a glass content of 25% by weight
3 and B4 were produced.

(2) Manufacture of Fiber Reinforced Thermoplastic Resin Composite Pipe A fiber reinforced thermoplastic resin composite pipe was manufactured according to the manufacturing process described with reference to FIG. The tape-shaped strips B3 or B4 were attached to the winding devices 18 and 19.

First, polypropylene (manufactured by Mitsui Petrochemical Co., Ltd., trade name "Hipol", linear expansion coefficient: about 11 to 13 ×)
Extruder 1 at 10 ⁻⁵ / ° C., Vicat softening point: about 120 ° C.)
The mixture was kneaded in No. 1 and extruded in a molten state into a tubular shape from the extrusion die 12 and passed through the first sizing device 13 while being water-cooled to continuously form a tubular core material P having an outer diameter of 50.2 mm.

Next, the core material P is applied to the crosshead die 15
Guided inside, and on the outer surface of the core material P, chlorinated polyvinyl chloride (manufactured by Tokuyama Sekisui Co., Ltd., trade name "HA-52K", linear expansion coefficient: about 7
˜8 × 10 ⁻⁵ , Vicat softening point: about 115 ° C.) was kneaded in the extruder 14 and extruded in a molten state to coat the inner layer Q having a thickness of about 3.1 mm.

Subsequently, on the downstream side of the crosshead die 15, on the outer surface of the inner layer Q covering the outer surface of the core material P, a tape-shaped strip in which a thermoplastic resin is held by continuous fibers arranged in the longitudinal direction. B3, B4 (thickness: 0.7 mm, width: 15
mm) is wound in a substantially circumferential direction while applying tension by winding devices 18 and 19 so that the inclination angles thereof are opposite to each other to form a multilayer tubular body in which a fiber-reinforced thermoplastic resin layer is formed on the outer surface of the inner layer Q. .

This multi-layer tubular body is introduced into the heating furnace 20 and
After heating to 0 ° C., it is passed through the second sizing device 21 and cooled with water, and a series of these steps is carried out while being taken by the take-up machine 22 and cut by the cutting machine 23 into a length of 3 m to be solidified. A multilayer tubular body was obtained. Next, the core material P is extracted from the obtained multilayer tubular body to have an inner diameter of about 51 mm and an outer diameter of about 60 mm.
A mm fiber reinforced thermoplastic resin composite tube was obtained.

Comparative Example 1 Sheet-shaped strips A1 and A2 and tape-shaped strips B1 and B
As 2, a fiber-reinforced thermoplastic resin composite pipe was manufactured by using the same one as in Example 1 according to the conventional manufacturing process shown in FIG.

The sheet-shaped strips A1 or A2 were mounted on the rewinding rolls 16 ', 17', and the tape-shaped strips B1 or B2 were mounted on the winding devices 18 ', 19'.

First, polyvinyl chloride (manufactured by Tokuyama Sekisui Co., Ltd., trade name "TS-1000R", linear expansion coefficient: approximately 7 to 8 × 10)
^-5 / ° C., Vicat softening point: about 80 ° C.) is kneaded in an extruder 11 ′ and extruded in a molten state into a tubular shape from an extrusion die 12 ′, and passed through a first sizing device 13 ′ while being water-cooled. A tubular inner layer having an outer diameter of 50.2 mm and a wall thickness of about 2.4 mm was continuously formed.

Subsequently, two sheet-like strips A1 and A2 (thickness: 0.7 mm, width: from the top and bottom of the outer surface of the inner layer).
At 80 mm), continuous fibers are laminated on the outer surface of the inner layer so as to be along the axial direction to form an intermediate layer, and further, on the outer surface of the intermediate layer, continuous fibers arranged in the longitudinal direction hold a thermoplastic resin. Tape-shaped strips B1 and B2 (thickness: 0.7 m
m, width: 20 mm) is wound in a substantially circumferential direction while applying tension by winding devices 18 'and 19' so that their inclination angles are opposite to each other, and a fiber-reinforced heat composed of an intermediate layer and an outer layer is formed on the outer surface of the inner layer. A multi-layer tubular body having a plastic resin layer was formed.

This multi-layer tubular body is introduced into a heating furnace 20 ', and the inside of the front end side of the multi-layer tubular body is supported by a support member 24' and a rubber plug 25 '.
The inside of the container is sealed, and the inside is pressurized at 0.5 kg / cm ² by the compressed air generator 26 ′, heated to 180 ° C., passed through the second sizing device 21 ′ and cooled with water. The above process was carried out while being taken up by the take-up machine 22 ', and cut into a length of 3 m by the cutting machine 23' to obtain a fiber-reinforced thermoplastic resin composite tube having an inner diameter of about 51 mm and an outer diameter of about 60 mm.

Comparative Example 2 Using the same tape-like strips B3 and B4 as in Example 2, a fiber-reinforced thermoplastic resin composite pipe was manufactured according to the conventional manufacturing process shown in FIG. Winding device 1
Tape-shaped strips B3 and B4 were attached to 8'and 19 '.

First, chlorinated polyvinyl chloride (manufactured by Tokuyama Sekisui Co., Ltd., trade name "HA-52K", linear expansion coefficient: about 7 to 8 x 1)
0 ^-5 / ° C., Vicat softening point: about 115 ° C.) the extruder 1
The mixture was kneaded in 1'and extruded in a molten state into a tubular form from an extrusion die 12 'and passed through the first sizing device 13' while being water-cooled to continuously form a tubular inner layer having an outer diameter of 50.2 mm. .

Subsequently, on the outer surface of the inner layer, tape-shaped strips B3 and B4 (thickness: 0.7 mm, width: 15 mm) in which thermoplastic resin is held by continuous fibers arranged in the longitudinal direction are wound around the winding device 18. ′, 19 ′ were applied in tension while being wound substantially in the circumferential direction so that their inclination angles were opposite to each other, and a fiber-reinforced thermoplastic resin layer was formed on the outer surface of the inner layer to obtain a multilayer tubular body.

This multi-layer tubular body is introduced into a heating furnace 20 ', and the inside of the front end side of the multi-layer tubular body is supported by a support member 24' and a rubber plug 25 '.
The inside of the container is sealed and the inside is pressurized at 0.5 kg / cm ² by the compressed air generator 26 ′, heated to 200 ° C., passed through the second sizing device 21 ′ and cooled with water. The above process was carried out while being taken up by the take-up machine 22 ', and cut into a length of 3 m by the cutting machine 23' to obtain a fiber-reinforced thermoplastic resin composite tube having an inner diameter of about 51 mm and an outer diameter of about 60 mm.

In Examples 1 and 2 and Comparative Examples 1 and 2,
For each of the five fiber-reinforced thermoplastic resin composite pipes obtained at the initial stage of production (about 1 hour after the start of production) and b after continuous operation for a long time (after about 40 hours from the start of production),
A repeated cooling and heating test was performed to observe the peeling condition of the interfaces at both ends. The results are shown in Table 1. As the cold heat condition, 85 ° C./25° C. = 5 minutes / 5 minutes was set as one cycle,
2,000 cycles at a water pressure of 1.5 Kg / cm ² ,
It was set to 5,000 cycles and 10,000 cycles.

The evaluation criteria are as follows. ◯: No peeling at the interface. Δ: One peeling (crack) having a width of 5 mm or less was found at the interface. X: Peeling (crack) with a width of 5 mm or more was observed at one place on the interface, or peeling (crack) with a width of 5 mm or less was seen at two or more places.

[0061]

[Table 1]

As described above, the fiber-reinforced thermoplastic resin composite pipes obtained according to the examples of the present invention are excellent in dimensional accuracy without peeling of the interface even after continuous operation for a long period of time. .

[0063]

EFFECT OF THE INVENTION Since the method for producing a fiber-reinforced thermoplastic resin composite pipe of the present invention is constructed as described above, the fusion at each interface of the multilayer tubular body is stabilized, and the fiber reinforced without quality variations. A thermoplastic resin composite pipe can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a process of an example of the present invention together with a manufacturing apparatus.

FIG. 2 is a perspective view showing a multilayer tubular body intermediately obtained by the present invention.

FIG. 3 is a perspective view showing an example of a fiber-reinforced thermoplastic resin composite tube obtained by the present invention.

FIG. 4 is a front view for explaining a process of another example of the present invention together with a manufacturing apparatus.

FIG. 5 is a front view illustrating a conventional example of a process along with a manufacturing apparatus.

FIG. 6 is a front view for explaining another conventional process along with a manufacturing apparatus.

[Explanation of symbols]

 A1, A2 Sheet-shaped strips B1, B2, B3, B4 Tape-shaped strips P Core material Q Inner layer R Intermediate layer S Outer layer T Multi-layer tubular body F Fiber reinforced thermoplastic resin composite pipe

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Claims (1)

[Claims] 1. A step of forming a core material by once cooling and solidifying an extruded thermoplastic resin tube, and a thermoplastic resin having a smaller coefficient of thermal expansion than the thermoplastic resin of the core material on the outer surface of the core material. A step of forming an inner layer by extrusion-coating a thermoplastic resin that is not compatible with the inner layer, and a continuous fiber that is arranged in the longitudinal direction on the outer surface of the inner layer and has a thermal expansion coefficient smaller than that of the thermoplastic resin of the core material. A step of forming a multi-layer tubular body by forming a fiber-reinforced thermoplastic resin layer by winding a belt-shaped body holding a thermoplastic resin compatible with the thermoplastic resin in a substantially circumferential direction, The temperature of the thermal expansion temperature to the thermal decomposition temperature of the plastic resin, the Vicat softening point of the thermoplastic resin of the fiber reinforced thermoplastic resin layer to the temperature of the thermal decomposition temperature, and then the step of cooling and solidifying, and the solidified multilayer The process consists of removing the core material from the tubular body. And a method for producing a fiber-reinforced thermoplastic resin composite pipe.