JPH0911353A - 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 wherein a tube of same performance as heretofore available can be produced and with improved efficiency of fusion bonding without making a production line longer when the diameter of the tube to be manufactured is larger or the production speed is increased. CONSTITUTION: A manufacturing method comprises the processes of forming a multilayer tubular body Q of two layers or more by laminating fiber reinforced thermoplastic resin layers P2 on the outer peripheral face of a thermoplastic resin tube P1, and then guiding the multilayer tubular body Q into a pressure reducing heating oven 18 and heating under the pressure reducing condition on the outside of the multilayer tubular body Q, and fusion bonding and integrating the thermoplastic resin tube P1 for fusion integrated with the fiber reinforced thermoplastic resin layer P2. The pressure reducing heating oven 18 provided with a high heat radiation rate layer having the heat radiation rate of 0.65 or over on its inner face is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced thermoplastic resin composite pipe in which a thermoplastic resin pipe is used as an inner layer and a fiber-reinforced thermoplastic resin layer is laminated on the outer peripheral surface of the pipe to form two or more layers. The present invention relates to a manufacturing method of.

[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 linear expansion coefficient between the inner layer and the fiber-reinforced resin layer, There is a problem of causing 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. There is known a method for producing a fiber-reinforced thermoplastic resin composite pipe having a strong fusion force with a resin layer.

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, when the multilayer tubular body is heat-sealed, either the pressurization of the inner atmosphere of the multilayer tubular body or the depressurization of the outer atmosphere thereof, or its Since the multilayer tubular body is exposed to heat in both atmospheres, heat is less likely to be transferred to the multilayer tubular body compared to the conventional heating method, and even if the heating amount is increased, there is a limit to increasing the molding speed. In particular, the tendency becomes remarkable as the diameter of the composite pipe to be molded becomes large.
Further, in the continuous molding line, a method of lengthening the heating furnace can be considered, but the production line becomes long, the facility investment increases, and at the same time, the heating is performed for a long time, so that the thermoplastic resin is thermally decomposed. There is a problem.

The present invention solves the above-mentioned conventional problems, improves the efficiency of heat fusion without lengthening the production line, and increases the production speed even if the diameter of the pipe to be produced is large. Even so, the object of the present invention is to provide a method for producing a fiber-reinforced thermoplastic resin composite pipe capable of producing a pipe having the same performance as the conventional one with high production efficiency.

[0009]

According to the present invention, a fiber-reinforced thermoplastic resin layer is laminated on the outer peripheral surface of a thermoplastic resin tube to form a multilayer tubular body having two or more layers, and then the multilayer tubular body is depressurized. Of a fiber-reinforced thermoplastic resin composite tube including a step of introducing into a heating furnace and heating it under a reduced pressure condition outside the multilayer tubular body to fuse and integrate the thermoplastic resin tube and the fiber-reinforced thermoplastic resin layer A method for producing a fiber-reinforced thermoplastic resin composite pipe, wherein the reduced pressure heating furnace has a high thermal emissivity layer having a thermal emissivity of 0.65 or more on its inner surface.

The reduced pressure heating furnace used in the present invention is
Those having a high thermal emissivity layer having a thermal emissivity of 0.65 or more on the inner surface are used, and those having a high thermal emissivity layer having a thermal emissivity of 0.85 or more are preferable because the effect is further enhanced.

The thermal emissivity referred to here is also called thermal emissivity, and is the radiant emittance of thermal radiation of an object and a black body (b) at the same temperature.
It is represented by the ratio of the radiant emittance of the heat radiation of the black body), and the closer the heat radiant emittance is to 1.0 of the black body, the larger the radiant emittance. When the thermal emissivity is less than 0.65, the thermal emissivity is small, the amount of thermal radiation is small, the heat transfer is insufficient under a reduced pressure atmosphere, and the thermoplastic resin pipe and the fiber-reinforced thermoplastic resin layer are efficiently provided. And cannot be heat fused.

As a substance having a thermal emissivity of 0.65 or more,
For example, C (graphite), Fe (oxide film), Ni (oxide film), CuO, FeO, NiO, SiO, TiO, Zr
C etc. are mentioned. The shape of the reduced-pressure heating furnace is preferably a cylindrical shape because it heats the multilayer tubular body, but is not limited thereto.

As a method for providing a high thermal emissivity layer having a thermal emissivity of 0.65 or more on the inner surface of a vacuum heating furnace, a high thermal emissivity layer is provided by applying a coating material having the above-mentioned substance components and then drying it. Alternatively, a method of baking iron, nickel, or the like on the inner surface of the decompression heating furnace to form an Fe (oxide film), Ni (oxide film), FeO, or NiO layer may be used.
Further, a cylindrical body or the like having the above layer on the inner surface may be laminated (bonded) on the inner surface of the reduced pressure heating furnace.

The thickness of the high thermal emissivity layer having a thermal emissivity of 0.65 or more is preferably 5 μm or more. 0.5μ thickness
When the thickness is less than m, it is difficult to transfer the heat applied to the heating furnace to the multilayer tubular body. The upper limit of the thickness is not particularly limited, but 100
If it exceeds μm, the amount of heat radiation in the reduced pressure heating furnace does not increase, and only the cost increases.
m or less is preferable. The main body of the reduced pressure heating furnace may be made of an ordinary inexpensive metal, such as iron.

The decompression power of the decompression heating furnace is usually 500
mmHg or more is preferable, and 600 mmHg or more is more preferable. If the decompression force is less than 500 mmHg, a sufficient lamination pressure cannot be applied to the multilayer tubular body.

The heating temperature of the reduced pressure heating furnace is preferably a Vicat softening temperature to a thermal decomposition temperature of the thermoplastic resin tube of the multilayer tubular body and the thermoplastic resin of the fiber reinforced thermoplastic resin layer, such as extrusion and injection molding of the above resin. It is more preferable that the temperature is around the molding temperature. When the heating temperature is lower than the Vicat softening temperature of the above-mentioned resin, the thermoplastic resin tube and the fiber-reinforced thermoplastic resin of the multilayer tubular body are heated even if the outside of the multilayer tubular body is heated under a reduced pressure of 500 mmHg or more. If the layers are not heat-sealed and the thermal decomposition temperature is exceeded, the performance of the obtained tube deteriorates.

The Vicat softening point is JIS K 7
The value measured according to 206. The Vicat softening temperature of a thermoplastic resin is, for example, about 65 for polyvinyl chloride.
~ 85 ° C, about 95-120 ° C for chlorinated polyvinyl chloride
It is. The term "heat fusion" means that both thermoplastic resins are heated to a molten state and then pressure-bonded, and after cooling, the fused interfaces do not easily break.

In the present invention, as the thermoplastic resin,
A thermoplastic resin suitable for the purpose of use of the obtained pipe is used, and examples thereof include polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyamide, polycarbonate, polyphenylene sulfide, polysulfone, polyether ether ketone, etc. Is mentioned.

These thermoplastic resins may be used alone or in combination of two or more kinds. In the thermoplastic resin, if necessary, additives such as heat stabilizers, plasticizers, lubricants, antioxidants, ultraviolet absorbers, pigments, inorganic fillers, reinforcing fibers, fillers, processing aids, A substance or the like may be added.

In the present invention, the form of laminating the fiber reinforced thermoplastic resin layer on the outer peripheral surface of the thermoplastic resin tube is a tape-like form in which the thermoplastic resin powder is adhered and fused between the continuous fibers. A band-shaped body such as a cord is preferable because it is usually easy to wind. In the present invention, examples of the material of the continuous fibers forming the fiber-reinforced thermoplastic resin layer include inorganic fibers such as glass fibers and carbon fibers, organic fibers such as aramid fibers, vinylon fibers and polyester fibers. Examples of the form of continuous fiber include monofilament, roving, strand, cloth, net,
Examples include a net shape.

The thickness of the monofilament constituting the continuous fiber is 1 to 100 μm because if the fiber is too thick, a portion where the thermoplastic resin is not retained 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.

The same continuous fibers as described 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 with 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 in and passed through a tank filled with the molten thermoplastic resin to adhere and solidify the thermoplastic resin 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.

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, and FIG. 2 is a sectional view showing a portion of a reduced pressure heating furnace,
FIG. 3 is a partially cutaway perspective view showing the fiber-reinforced thermoplastic resin composite pipe obtained.

First, the manufacturing apparatus will be described. The manufacturing apparatus is an extruder 11 for extruding a thermoplastic resin tube as an inner layer.
An extrusion die 12 attached to the tip of the extruder 11, and rewinding rolls 13 and 14 to which the sheet-shaped strips A1 or A2 arranged on the upper and lower sides of the extrusion die 12 are attached,
A winding device 15 around which the tape-shaped strip B1 or B2 is wound,
16, a decompression heating furnace 18 capable of decompressing with a vacuum pump 17, a crosshead die 20 for extruding a thermoplastic resin as an outer layer from an extruder 19 to cover the outer layer as necessary, and a second sizing device. 21 and a take-up machine 22 are sequentially arranged.

The depressurizing heating furnace 18 is provided with a seal rubber 181 having a through hole for allowing the multilayer tubular body to pass therethrough.
A high thermal emissivity layer 182 having a thermal emissivity of 0.65 or more is provided on the inner surface, a heater 183 is provided on the outer periphery, and a decompression port 184 communicating from the outside to the inside is provided.

Next, the steps of an example of the present invention using this manufacturing apparatus will be described. A thermoplastic resin pipe P which is an inner layer of the extrusion die 12 by melting and kneading a thermoplastic resin in the extruder 11.
Push 1 continuously.

An axial reinforcing layer P21 is laminated on the outer peripheral surface of the thermoplastic resin pipe P1 from above and below by two sheet-like strips A1 and A2 so that continuous fibers are along the axial direction, and further the outer periphery thereof. Tape-like strips B1 and B2 in which thermoplastic resin is held by continuous fibers arranged in the longitudinal direction on the surface are applied in tension by the winding devices 15 and 16 and substantially inclined in the circumferential direction so that the mutual inclination angles are opposite to each other. Wrap around and wrap around circumferential reinforcement layer P2
2 to form the axial reinforcing layer P22 and the circumferential reinforcing layer P22.
A multilayer tubular body Q in which a fiber reinforced thermoplastic resin layer P2 composed of

This multi-layer tubular body Q is introduced into the reduced pressure heating furnace 18, and the outer side of the multi-layer tubular body Q is 500 m by the vacuum pump 17.
The pressure is reduced to mHg or more, and the heater 183 heats the thermoplastic resin pipe P1 and the fiber-reinforced thermoplastic resin layer P2 to the Vicat softening point to the thermal decomposition temperature of the thermoplastic resin.

At this time, by depressurizing the outside of the multilayer tubular body Q, an expansion pressure acts on the entire multilayer tubular body Q,
The interfaces of the thermoplastic resin pipe P1, the axial reinforcing layer P22, and the circumferential reinforcing layer P22 are in a close contact state. Since the high thermal emissivity layer 182 having a thermal emissivity of 0.65 or more is provided on the inner surface of the reduced pressure heating furnace 18, the heat heated by the heater 183 is transmitted to the thermoplastic resin of each layer even under a reduced pressure. As a result, the thermoplastic resin of each layer is melted and integrated.

Subsequently, the multilayer tubular body Q is guided into the crosshead die 20 as required, and the outer peripheral surface of the multilayer tubular body Q is melt-kneaded by the extruder 19 and extrusion-coated. The outer layer P3 is formed.

This multilayer tubular body is passed through the sizing device 21 for cooling. As a result, the thermoplastic resin of each layer is heat-sealed. The above-mentioned series of steps is carried out while being taken by the take-up machine 22, and cut into an appropriate length by a not-shown cutting machine to continuously produce a fiber-reinforced thermoplastic resin composite pipe as shown in FIG. To do. 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.

[0035]

The method for producing a fiber-reinforced thermoplastic resin composite pipe of the present invention is a vacuum heating furnace having a thermal emissivity of 0.65 on its inner surface.
By using the one having the high thermal emissivity layer as described above, in the reduced pressure heating furnace, the expansion pressure acts on the entire multilayer tubular body, and the thermoplastic resin tube and the fiber-reinforced thermoplastic resin layer are in a close contact state, Heat that is heated to the thermoplastic resin of each layer is transmitted even under a reduced pressure, the thermoplastic resin of each layer is melted and integrated, and since it can be heat-sealed through a cooling step thereafter, without lengthening the production line, It is possible to produce a fiber-reinforced thermoplastic resin composite tube with excellent interfacial adhesion strength that is the same as before even if the efficiency of heat fusion is increased, the diameter of the tube to be manufactured is increased, and the production speed is increased. it can.

[0036]

The present invention will be described below with reference to examples. Example 1 (1) Production of a sheet-shaped strip and a tape-shaped strip A roving-shaped glass fiber bundle (4,400 tex) composed of filaments having a diameter of 23 μm was mixed with powdered polyvinyl chloride (manufactured by Tokuyama Sekisui Co., Ltd.). , Product name "TS-1000
R ", degree of polymerization: 1000) to pass through a fluidized bed to deposit polyvinyl chloride in powder form between the fibers, which is about 2
The thermoplastic resin is held by continuous fibers arranged in the longitudinal direction by thermocompression bonding with a pair of heating rolls heated to 00 ° C (sheet thickness: A1, A2 (thickness:
About 0.7 mm, width: about 88 mm), and tape-shaped band B
1, B2 (thickness: about 0.2 mm, width: about 20 mm) were produced. The fiber content of each of them was 25% by weight.

(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. As the reduced-pressure heating furnace 18, three sealing dusts 181 each having a through hole for allowing a multilayer tubular body to pass therethrough are provided, and a high thermal emissivity paint (manufactured by Western Trading Co., Ltd.) is provided on the inner surface of the main body made of iron. A high thermal emissivity layer (thermal emissivity: approximately 0.9) formed by applying a name "Pyromark", a coating material containing graphite, chromium oxide, an inorganic solvent, etc., to a thickness of about 25 μm and drying it.
4) was used. Rewind roll 13,
The sheet-shaped strip A1 or A2 was attached to 14 and the tape-shaped strip B1 or B2 was attached to the winding devices 15 and 16.

First, polyvinyl chloride (manufactured by Tokuyama Sekisui Co., Ltd., trade name "TS-1000R", degree of polymerization: 1000) is melt-kneaded in an extruder 11 and extruded from an extrusion die 12 with an inner diameter of about 5
A thermoplastic resin pipe P1 having a diameter of 1 mm and an outer diameter of about 55 mm was continuously extruded.

Subsequently, on the downstream side of the extrusion die 12,
Two sheet-shaped strips A1 and A2 (thickness: 0.7 mm, width: 80 m) on the outer peripheral surface of the thermoplastic resin pipe P1 from above and below.
m) so that the continuous fiber is along the axial direction, the axial reinforcing layer P
21 is laminated, and the tape-shaped band B in which the thermoplastic resin is held by continuous fibers arranged on the outer peripheral surface in the longitudinal direction.
1, B2 (thickness: 0.2 mm, width: 20 mm) are wound in a substantially circumferential direction while applying tension by the winding devices 15 and 16 so that their inclination angles are opposite to each other.
22 to form a fiber-reinforced thermoplastic resin layer P2 including an axial-direction reinforcing layer P21 and a circumferential-direction reinforcing layer P22.
To form a multilayer tubular body Q.

This multi-layered tubular body Q was introduced into the reduced pressure heating furnace 18 (total length 700 mm), the outer side of the multi-layered tubular body Q was reduced by 600 mmHg by the vacuum pump 17 to 160 mmHg, and the heater 183 (set temperature was 230 ° C.). The multi-layer tubular body was heated at. The outer surface temperature of the multilayer tubular body at this time was 170 ° C.

Subsequently, the multilayer tubular body Q is guided into the crosshead die 20, and polyvinyl chloride (manufactured by Tokuyama Sekisui Co., Ltd., trade name "TS-1000" is attached to the outer peripheral surface of the multilayer tubular body Q.
R ”and the degree of polymerization: 1000) were melt-kneaded in the extruder 19 and extrusion-coated (performed while applying the above depressurizing force) to form the outer layer P4.

This multilayer tubular body was passed through the sizing device 21 for cooling. The above-mentioned series of steps is carried out while being taken by the take-up machine 22 at a speed of 0.5 m / min, and cut into an appropriate length by a cutting machine not shown in FIG.
A fiber-reinforced thermoplastic resin composite pipe having an inner diameter of about 51 mm and an outer diameter of about 60 mm as shown in (4) was continuously manufactured.

Example 2 Example 1 except that the molding speed was set to 1 m / min and the set temperature of the heater 183 of the vacuum heating furnace was set to 300 ° C.
A fiber-reinforced thermoplastic resin composite tube was continuously produced in the same manner as in. At this time, the outer surface temperature of the multilayer tubular body in the heating furnace was 165 ° C.

Example 3 As the reduced pressure heating furnace 18, FeO was formed on the inner surface of the main body made of iron.
A high thermal emissivity layer (thermal emissivity: approximately 0.95) having a thickness of about 15 μm containing many components was used, and the set temperature of the heater 183 of the vacuum heating furnace was 220 ° C.
The fiber-reinforced thermoplastic resin composite pipe was continuously manufactured in the same manner as in Example 1 except that the depressurizing force was 700 mmHg. At this time, the outer surface temperature of the multilayer tubular body in the heating furnace was 175 ° C.

Example 4 The same reduced pressure heating furnace as in Example 3 was used, the molding speed was 1 m / min, the set temperature of the heater 183 of the reduced pressure heating furnace was 290 ° C., and the reducing pressure was 550 mmH.
A fiber-reinforced thermoplastic resin composite tube was continuously manufactured in the same manner as in Example 1 except that the value was changed to g. At this time, the outer surface temperature of the multilayer tubular body in the heating furnace was 175 ° C.

Comparative Example 1 A reduced pressure heating furnace having a high thermal emissivity layer on its inner surface (main body made of iron, thermal emissivity: about 0.4) was used, and the set temperature of the heater of the reduced pressure heating furnace was used. A fiber-reinforced thermoplastic resin composite pipe was continuously manufactured in the same manner as in Example 1 except that the temperature was set to 300 ° C. At this time, the outer surface temperature of the multilayer tubular body in the heating furnace was 140 ° C.

Comparative Example 2 A reduced pressure heating furnace having a high thermal emissivity layer on its inner surface (main body made of iron, thermal emissivity: about 0.4) was used, and the molding rate was 1 m / min. That is, a fiber-reinforced thermoplastic resin composite pipe was continuously manufactured in the same manner as in Example 1 except that the set temperature of the heater of the vacuum heating furnace was set to 380 ° C. At this time, the outer surface temperature of the multilayer tubular body in the heating furnace was 120 ° C.

The interfacial adhesion strength of the fiber-reinforced thermoplastic resin composite tubes obtained in Examples 1 to 4 and Comparative Examples 1 and 2 was evaluated. The evaluation was performed on a ring-shaped sample (ring width 2 cm) by a shear strength test with reference to the JWWA116 method for a water pipe hard vinyl chloride lining steel pipe (n = 5). The results are shown in Table 1.

[0049]

[Table 1]

As is clear from Table 1, the interface shear strengths of the examples of the present invention are higher than those of the comparative examples.

[0051]

EFFECTS OF THE INVENTION The method for producing a fiber-reinforced thermoplastic resin composite pipe of the present invention is constructed as described above, and therefore the pipe to be produced by increasing the heat fusion efficiency without lengthening the production line. Even if the diameter of the
It is possible to manufacture a fiber-reinforced thermoplastic resin composite pipe excellent in interfacial adhesion strength, which is not different from conventional ones.

[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 sectional view showing an example of a reduced pressure heating furnace used in the present invention.

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

[Explanation of symbols]

 18 Decompression heating furnace 182 High thermal emissivity layer P1 Thermoplastic resin tube P2 Fiber reinforced thermoplastic resin layer Q Multi-layer tubular body

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29K 101: 12 105: 08 B29L 9:00

Claims (1)

[Claims] 1. A multi-layered tubular body is prepared by laminating a fiber-reinforced thermoplastic resin layer on the outer peripheral surface of a thermoplastic resin tube to form a multi-layered tubular body having two or more layers, and then introducing the multi-layered tubular body into a reduced pressure heating furnace. A method for producing a fiber-reinforced thermoplastic resin composite pipe, which comprises heating the thermoplastic resin pipe and a fiber-reinforced thermoplastic resin layer to be fused and integrated under reduced pressure conditions outside the body, wherein the reduced pressure is A method for producing a fiber-reinforced thermoplastic resin composite pipe, characterized in that a heating furnace having a high thermal emissivity layer having a thermal emissivity of 0.65 or more on its inner surface is used.