JPH08156113A - Manufacture of fiber reinforced thermoplastic resin composite tube - Google Patents

Abstract

PURPOSE: To enable a fiber-reinforced thermoplastic resin composite tube to be manufactured efficiently wherein a thermoplastic resin layer laminated on an inner surface is little in one-side thickness, and fusion welding of a resin tube to a reinforced fiber composite is strong without raising extrusion pressure of the resin. CONSTITUTION: At least three fiber-reinforced thermoplastic resin sheets 100 are transferred longitudinally inside an outer die 40 for control of an outside diameter, and combined into a tubular shape of a plygonal section corresponding to the number of the sheets 100 at an inlet of the outer die 40. Thermoplastic resin 10a is extruded tubularly on an inner surface of the tubular combined material 101 from an extrusion die 30, and laminated with a polygonal section part 41 of the outer die 40 to form a tubular shape of the polygonal section. The tubular material 102 is shaped into a tubular shape of a circular or elliptical section by inner pressure of air with a section-enlarged part 42 of the outer die and its circular or elliptical section part 43. By covering an outer periphery of the shape tubular material 103 with a thermoplastic resin by extrusion as occasion demands, a target fiber-reinforced thermoplastic resin composite tube 104 is obtained.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Fiber-reinforced thermoplastic resin composite pipes have superior characteristics such as being lighter in weight and less rusting than metal pipes, and also have higher pressure resistance, impact resistance, hot water resistance, etc. than thermoplastic resin pipes. It is widely used for piping for transferring various fluids such as hot water, gas and chemicals, as well as piping for electric wiring and structural members.

As a method for producing this type of fiber-reinforced thermoplastic resin composite pipe, Japanese Patent Laid-Open No. 3-158219 discloses a method.
A method in which one sheet of fiber reinforced thermoplastic resin is transferred in the longitudinal direction to form a tubular shape in a crosshead extrusion die, and the thermoplastic resin is extruded into a tubular shape from the crosshead extrusion die and laminated on the inner surface of the tubular body. Is proposed.

Further, Japanese Patent Application Laid-Open No. 4-8983 discloses that
Two fiber reinforced thermoplastic resin sheets are transferred in the longitudinal direction, a long straight extrusion die is used as a mandrel to surround the outer periphery in a tubular shape, and a similar fiber reinforced thermoplastic resin sheet is wound around the outer periphery, and both sheets are wrapped. A method has been proposed in which heat-sealing is performed to form a tubular shape, and a thermoplastic resin is extruded into a tubular shape from the straight extrusion die and laminated on the inner surface of the tubular body.

In any of the above-mentioned methods, the tubular body made of the fiber reinforced thermoplastic resin sheet and the thermoplastic resin layer laminated thereon are firmly fused to each other, and the pressure resistance, impact resistance, hot water resistance, etc. And has the advantage that it can be continuously and efficiently manufactured.

[0006]

However, in the former method of the above proposed methods, a thermoplastic resin must be extruded and laminated on the inner surface of the tubular body by using a crosshead extrusion die. With a crosshead extrusion mold,
Since the resin flow path in the mold is curved, the resin is unevenly flown and extruded, and the uneven thickness of the resin layer laminated on the inner surface of the tubular body increases. Further, if a single fiber-reinforced thermoplastic resin sheet is used to form a tubular shape, it becomes difficult to form a tubular body having an excessively large diameter.

In the latter method of the above proposed methods, the thermoplastic resin must be extruded and laminated on the inner surface of the tubular body by using an elongated straight extrusion die which also serves as a mandrel. When a mold is used, the thickness of the resin layer does not vary much, but the resin flow path inside the mold is considerably long, so the extrusion pressure becomes extremely high, and the amount of resin extruded cannot be increased. . Further, since the residence time of the resin in the mold becomes long, the resin may be thermally decomposed.

The present invention solves the above-mentioned problems of the prior art. The object of the present invention is to reduce the uneven thickness of the thermoplastic resin layer laminated on the inner surface and to prevent the resin extrusion pressure from increasing. Moreover, it is another object of the present invention to provide a method capable of efficiently producing a fiber-reinforced thermoplastic resin composite pipe in which fusion bonding between the resin pipe and the reinforcing fiber composite is strong.

[0009]

The method for producing a fiber-reinforced thermoplastic resin composite pipe according to the present invention is to transfer at least three fiber-reinforced thermoplastic resin sheets in the longitudinal direction to obtain a cross-section having a number of cross sections corresponding to the number of the sheets. Combining into a rectangular tube, extruding a thermoplastic resin into a tubular shape on the inner surface of the tubular combination to form a tube with a polygonal cross section, and shaping this tube into a tube with a circular or elliptical cross section by internal pressure. The above object can be achieved thereby.

The method for producing the fiber-reinforced thermoplastic resin composite pipe of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic explanatory view showing an example of the method of the present invention. In FIG. 1, 10 is a fiber-reinforced resin sheet feeding roll, 20 is a first extruder, 30 is an extrusion die for inner layer extrusion attached to the first extruder 20, and 40 is an outer die for outer diameter regulation. Is.

An air press-fitting hole 31 is provided in the extrusion die 30, one end of which is connected to a compressed air source 32, and the other end of which is opened at the tip surface of the extrusion die 30. The outer die 40 for controlling the outer diameter is composed of a portion 41 having a polygonal cross section, an enlarged portion 42 having a cross section gradually enlarged from this portion 41 into a circular or elliptical shape, and a portion 43 having a circular or elliptical cross section. It is configured.

In the outer mold 40, the cross-sectional shape of the polygonal section 41 is determined by the size and number of the fiber-reinforced thermoplastic resin sheets used. For example, when four sheets are used, the portion 41 having a polygonal cross section becomes a portion 41 having a quadrangular cross section corresponding to the number of sheets, and when using eight sheets, the portion 41 having a polygonal cross section is Octagonal section 4 corresponding to the number of sheets 4
It becomes 1.

Further, the portion 43 having a circular or elliptical cross section is
It is determined by the cross-sectional shape of the fiber-reinforced thermoplastic resin composite pipe to be produced, and the circular or elliptical shape includes a true circular shape and a true elliptical shape, as well as an oval shape and an oval shape.

Then, the air press-fitting hole 31 of the extrusion die 30 is provided inside the circular or elliptical section 43 of the outer die 40.
A disc-shaped or elliptical-plate-shaped seal plug 50 is provided to seal the air press-fitted from, and the seal plug 50 is prevented from moving by the wire 51 extended from the tip surface of the extrusion die 30. It is fixed.

Further, in front of the outer die 40, there are provided a second extruder 60, an extrusion die 70 for coating the outer layer attached to the second extruder 60, a sizing cooling die 80, and a take-off machine 90. There is. The second extruder 60 and the extrusion die 70 for coating the outer layer are provided as needed.

First, at least 3 from the feeding roll 10
The sheet of fiber-reinforced thermoplastic resin sheet 100 is transferred to the inside of the outer die 40 for controlling the outer diameter so as to surround the extrusion die 30 in the longitudinal direction. Then, at the entrance of the portion 41 having a polygonal cross section, the outer die 40 is combined into a tubular shape having a polygonal cross section corresponding to the number of sheets.

When the fiber-reinforced thermoplastic resin sheet 100 is assembled in a tubular shape having a polygonal cross section, the fiber-reinforced thermoplastic resin sheets 100 are assembled by abutting or contacting the side edges of the sheets so that no gap is formed. It in this case,
It is preferable to combine them in a regular cross section. For example, when using four sheets 100, (a), (b) in FIG.
The state shown in (c) is combined in a tubular shape with a regular square cross section. 3A shows the XX cross section of FIG. 1, and shows a tubular combination body 101 having a regular quadrangular cross section that is combined as shown in FIG.

The fiber-reinforced thermoplastic resin sheet is obtained by impregnating a large number of roving-like or strand-like reinforcing fibers with a thermoplastic resin, and is manufactured by a known method.

For example, as described in detail in JP-A-3-158219 and JP-A-4-8983, roving-like or strand-like reinforcing fibers are provided in a fluidized bed of thermoplastic resin powder. A method in which a resin is adhered and impregnated between the fibers by passing it through, and the fibers are heated and pressurized to be integrated is preferably adopted.

In addition, a roving-shaped or strand-shaped reinforcing fiber is passed through a dispersion liquid or solution of a thermoplastic resin powder to impregnate and impregnate a resin between the fibers, and then dried, which is heated and pressed to be integrated. In addition to the method and a method of laminating a thermoplastic resin film on a cross-shaped, mesh-shaped or net-shaped reinforcing fiber in which continuous fibers are arranged in the longitudinal direction, and heating and pressurizing this, the reinforcing fiber is swirl-shaped. The method of using a thing is adopted.

As the reinforcing fiber, inorganic fiber such as glass fiber, carbon fiber and metal fiber, synthetic fiber such as aramid fiber and vinylon fiber are used. As a thermoplastic resin,
Polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyamide, polycarbonate, polyphenylene sulfide, polyaryl ether sulfone, polyaryl ether ketone, etc. are used.

The thickness of the reinforcing fiber is 1 to 100 μm, preferably 3 to 50 μm, the content of the reinforcing fiber is 3 to 70% by weight, preferably 10 to 50% by weight, and the thickness of the fiber reinforced thermoplastic resin sheet is 0.1-5 mm, preferably 0.3-
The sheet width is 2 mm, and the sheet width is appropriately determined depending on the number of sheets to be used and the dimensions of the fiber-reinforced thermoplastic resin composite tube to be produced.

Subsequently, at the portion 41 of the outer die 40 having a polygonal cross section, the thermoplastic resin 10a is extruded in a tubular shape and laminated on the inner surface of the tubular combination body 101 to form a tubular shape having a polygonal cross section. In order to extrude and laminate the thermoplastic resin 10a on the inner surface of the tubular combination body 101 in a tubular shape, the thermoplastic resin 10a is extruded from the extrusion die 30 to form the tubular combination body 10.
A method in which, while extruding into a tubular shape having a polygonal cross-section similar to that of No. 1 and passing through an extrusion die 30 into this tube, for example, air or the like is pressed and laminated, is suitably adopted.

In addition, the thermoplastic resin 1 is fed from the extrusion die 30.
0a is extruded into a tubular shape having a circular cross section, and air or the like is forced into the tube through an extrusion die 30 to expand the tube in the radial direction so that the tubular combination body 101 is laminated on the inner surface thereof. FIG. 3B shows a YY cross section of FIG. 1, and shows a tubular body 102 having a regular quadrangular cross section formed by the former method.

As the thermoplastic resin 10a laminated on the inner surface of the tubular combination 101, a thermoplastic resin having a good compatibility with the resin constituting the fiber reinforced thermoplastic resin sheet is used, and for example, polyvinyl chloride or chlorinated. PVC,
It is selected from polyethylene, polypropylene, polystyrene, polyamide, polycarbonate, polyphenylene sulfide, polyaryl ether sulfone, polyaryl ether ketone, and the like.

These thermoplastic resins may contain additives such as heat stabilizers, lubricants, plasticizers, antioxidants, ultraviolet absorbers, pigments, fillers, processing aids and modifiers, if necessary. Is blended.

Subsequently, the tubular body 10 having the polygonal cross-section described above.
2 is transferred to a circular or elliptical section 43 through a sectional enlarged section 42 whose section is gradually enlarged into a circular or elliptical section. Extrusion die 30 in the pipe of 102
It is shaped into a circular or elliptical cross section by the internal pressure of the air press-fitted through. FIG. 3C shows the ZZ cross section of FIG. 1, and shows the shaped tubular body 103 whose cross section is shaped into a perfect circle.

The tubular body 102 and the shaped tubular body 103
The internal pressure due to the air, etc. used to obtain the product is generally 0.05 to 5 kg / cm ² although it depends on the diameter of the composite pipe to be manufactured.
Is more preferable and 0.1 to ² kg / cm ² is more preferable. In addition, the temperature of the resin when applying the internal pressure is appropriately selected in consideration of the type of the resin, the bore diameter of the tube, and the internal pressure, above the Vicat softening temperature of the resin, below the melting point, and in accordance with the molding conditions within the range that does not cause thermal decomposition. However, it is particularly preferable that the resin is in a molten state.

The shaped tubular body 103 is, if necessary,
Extrusion die 70 attached to the second extruder 60 for coating the outer layer
The same thermoplastic resin as described above is extrusion-coated on the surface, cooled by the sizing cooling die 80, and taken by the take-off machine 90. In this way, the fiber-reinforced thermoplastic resin composite pipe 104 is manufactured.

[0031]

As in the present invention, at least three fiber reinforced composite sheets are transferred in the longitudinal direction and combined into a tubular shape having a polygonal cross section corresponding to the number of sheets, and a thermoplastic resin is applied to the inner surface of the combined body in a tubular shape. When it is extruded and laminated to form a tube having a polygonal cross section, and this tubular body is shaped into a tube having a circular or elliptical cross section by an internal pressure, a straight mold is used to use at least three fiber-reinforced composite sheets. You can Therefore, the resin does not flow unevenly in the mold, and the variation in the thickness of the resin layer laminated on the inner surface of the tubular body is reduced.

When at least three fiber-reinforced composite sheets are used to form a tube, a tubular body having a large diameter can be easily assembled and the length of the straight mold can be made relatively short. Therefore, the extrusion pressure of the resin is prevented from increasing, and the extrusion amount of the resin can be increased. Also, the residence time of the resin in the mold is short, and there is no risk of the resin thermally decomposing.

[0033]

EXAMPLES Examples and comparative examples of the present invention will be shown below. Example 1 Production of Fiber Reinforced Thermoplastic Resin Sheet Roving glass fibers (4400 tex) made of filaments having a diameter of 23 μm were opened and aligned to obtain chlorinated polyvinyl chloride powder (chlorine content 64% by weight, average degree of polymerization 550). , An average particle size of 100 μm), and the resin powder is impregnated and adhered to the gaps between the reinforcing fibers. This is passed through a heating and pressure roll heated to 230 ° C to melt the resin powder and form a sheet, which is cut in the longitudinal direction to have a thickness of 1 mm and a width of 77 m.
A fiber reinforced thermoplastic resin sheet 100 having m and a glass fiber content of 20% by weight was obtained.

Manufacture of Fiber Reinforced Thermoplastic Resin Composite Pipe First, as shown in FIG. 1, four fiber reinforced thermoplastic resin sheets 100 were transferred in the longitudinal direction and combined in a tubular shape having a square cross section. Chlorinated polyvinyl chloride (chlorine content: 64% by weight, average degree of polymerization: 5) was formed on the inner surface of the tubular assembly 101.
50) 10a was melt-extruded into a tube at 195 ° C. and laminated by using the resin pressure and the pressure of pressurizing air to form a tube having a square cross section. The total length of the extrusion die 30 was 600 mm, and the extrusion pressure was 150 kg / cm ² .

Air was pressed into the tubular body 103 having a square cross section at a pressure of 0.3 kg / cm ² , and the tube was shaped into a circular cross section by the internal pressure of the air. The shaped tubular body 103 having a circular cross section is passed through the second extrusion die 70, and the outer periphery thereof is extrusion coated with chlorinated polyvinyl chloride (chlorine content 64% by weight, average degree of polymerization 550) at 195 ° C., and sizing cooling The fiber-reinforced thermoplastic resin composite tube 104 was obtained by being cooled by the mold 80 and taken by the take-off machine 90. The line speed was 2 m / min.

Fiber-reinforced thermoplastic resin composite tube 10 obtained
In No. 4, the inner diameter was 100 mm, the outer diameter was 114 mm, the wall thickness was 7 mm, the inner layer resin thickness was 3 mm ± 0.05 mm, and the uneven thickness of the inner layer resin was extremely small.

Example 2 Production of Fiber Reinforced Thermoplastic Resin Sheet Polyvinyl chloride powder (average degree of polymerization: 1000, average particle size: 100 μm) was used in place of the chlorinated polyvinyl chloride powder,
In the same manner as in Example 1, a fiber-reinforced thermoplastic resin sheet 100 having a thickness of 1.5 mm, a width of 75 mm and a glass fiber content of 20% by weight was obtained.

Manufacture of Fiber Reinforced Thermoplastic Resin Composite Tube First, as shown in FIG. 1, eight of the above fiber reinforced thermoplastic resin sheets 100 were transferred in the longitudinal direction and combined into a tubular shape having a regular octagonal cross section. Polyvinyl chloride (average degree of polymerization 1000) 10a was melt extruded into a tubular shape at 190 ° C. on the inner surface of the tubular assembly 101, and laminated using the resin pressure and the pressure of the pressurizing air to form a regular octagonal tubular section. The total length of the extrusion die was 1000 mm, and the extrusion pressure was 120 kg / cm ² .

Air was pressed into the inside of the tubular body 102 having a regular octagonal cross section at a pressure of 0.4 kg / cm ² , and the tube was shaped into a circular cross section by the internal pressure of the air. This shaped tubular body 103 having a circular cross section was passed through a second extrusion die 70, and chlorinated polyvinyl chloride (chlorine content 64% by weight, average degree of polymerization 550) was passed through the second extrusion die 70 at 195 ° C. in the same manner as in Example 1. Extrusion coating and cooling with a sizing cooling die 80, and a take-up machine 9
Fiber reinforced thermoplastic resin composite pipe 10
4 was produced. The line speed was 2 m / min.

Fiber-reinforced thermoplastic resin composite tube 10 obtained
In No. 4, the inner diameter was 195 mm, the outer diameter was 215 mm, the wall thickness was 10 mm, the thickness of the inner layer resin was 5 mm ± 0.05 mm, and the uneven thickness of the inner layer resin was extremely small.

Comparative Example 1 Production of Fiber Reinforced Thermoplastic Resin Sheet By the same method as in Example 1, a fiber reinforced thermoplastic resin sheet having a thickness of 1 mm, a width of 340 mm and a glass fiber content of 20% by weight was obtained.

Manufacture of Fiber Reinforced Thermoplastic Resin Composite Tube Based on the example of Japanese Patent Laid-Open No. 3-158219.
One of the above-mentioned fiber reinforced thermoplastic resin sheets is transferred in the longitudinal direction and formed into a tubular shape having a circular cross section in a crosshead extrusion die. The inner surface of the tubular body having the circular cross section has a chlorinated polyvinyl chloride (chlorine content of 64%). % By weight and an average degree of polymerization of 550) are melt-extruded and laminated in a tubular shape from the above crosshead extrusion die at 195 ° C., and chlorinated polyvinyl chloride (chlorine content: 64% by weight, average) on the outer periphery thereof in the same manner as in Example 1. Degree of polymerization 550)
Was extruded at 195 ° C., cooled by a sizing cooling mold, and taken by a take-up machine to produce a fiber-reinforced thermoplastic resin composite pipe. The line speed was 2 m / min.

The total length of the crosshead extrusion die is 800.
mm, the extrusion pressure was 210 kg / cm ² . The fiber-reinforced thermoplastic resin composite pipe obtained has an inner diameter of 100 mm and an outer diameter of 11
4mm, wall thickness about 7mm, inner layer resin thickness is 3mm ± 0.3mm
Therefore, the uneven thickness of the inner layer resin was extremely large.

Comparative Example 2 Production of Fiber Reinforced Thermoplastic Resin Sheet Polyvinyl chloride powder (average degree of polymerization: 1000, average particle size: 100 μm) was used in place of the chlorinated polyvinyl chloride powder,
In the same manner as in Example 1, a fiber-reinforced thermoplastic resin sheet having a thickness of 1.5 mm, a width of 80 mm and a glass fiber content of 20% by weight was obtained.

Manufacture of Fiber Reinforced Thermoplastic Resin Composite Tube Based on the example of Japanese Patent Application Laid-Open No. 4-8983.
Eight sheets of the above fiber reinforced thermoplastic resin sheets are transferred in the longitudinal direction, a slender extrusion die is used as a mandrel and is surrounded by a tubular shape with a circular cross-section, and similar fiber reinforced thermoplastic resin sheets are formed in the outer periphery of the mandrel with gaps or overlaps. So as not to occur, both sheets were heat-sealed to form a tubular body having a circular cross section.

Polyvinyl chloride (average degree of polymerization of 1000) was melt-extruded in a tubular form at 190 ° C. from an elongated extrusion die and laminated on the inner surface of the circular cross section, and polyvinyl chloride (average degree of polymerization was averaged on the outer periphery thereof) in the same manner as in Example 1. (1000 degree) was extruded at 190 ° C., cooled by a sizing cooling mold, and taken by a take-up machine to produce a fiber-reinforced thermoplastic resin composite pipe. The line speed was 2 m / min.

The length of the elongated extrusion die which also serves as the mandrel was 1400 mm and the extrusion pressure was 320 kg / cm ² , and the extrusion pressure was remarkably high. The fiber-reinforced thermoplastic resin composite tube obtained has an inner diameter of 195 mm, an outer diameter of 215 mm, and a wall thickness of 10 mm.
The thickness of the inner layer resin was 5 mm ± 0.05 mm, and the uneven thickness of the inner layer resin was extremely small.

[0048]

As described above, according to the method for producing a fiber-reinforced thermoplastic resin composite pipe of the present invention, at least three fiber-reinforced thermoplastic resin sheets are transferred in the longitudinal direction and the cross-sectional area corresponding to the number of sheets is increased. Combined in a rectangular tube, and extruding a thermoplastic resin in a tubular shape on the inner surface of this tubular combination to form a tube having a polygonal cross section, and shaping this tube into a tube having a circular or elliptical cross section by an internal pressure. And then
Compared with the conventional technology, the uneven thickness of the thermoplastic resin layer laminated on the inner surface is small, the extrusion pressure of the resin does not increase, and the fusion bonding between the resin tube and the reinforcing fiber composite is strong, and the pressure resistance and resistance are high. It is possible to efficiently manufacture a fiber-reinforced thermoplastic resin composite tube having excellent fiber reinforcing effects such as impact resistance and hot water resistance.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of the method of the present invention.

2 (a), (b), and (c) are cross-sectional views showing an example in which four fiber-reinforced thermoplastic resin sheets are combined in a tubular shape having a regular square cross section.

3A is a sectional view taken along line XX in FIG. 1, FIG. 3B is a sectional view taken along line YY in FIG. 1, and FIG.
It is a Z sectional view.

[Explanation of symbols]

 30 Extrusion Die for Inner Layer Extrusion 31 Air Press-in Hole 40 Outer Die for Outer Diameter Control 41 Polygonal Section of Outer Die 42 Expanded Section of Outer Die 43 Cross Section of Outer Die Circular or Elliptical Part 50 Disc-shaped or elliptical seal plug 70 Extrusion die for outer layer coating 80 Sizing cooling type 90 Take-off machine 100 Fiber reinforced thermoplastic resin sheet 101 Combination body combined in a tubular shape having a polygonal cross section 10a Inner surface of combination body Thermoplastic resin 102 laminated in a tubular shape tubular body 103 having a polygonal cross section 103 shaped tubular body 104 having a circular or elliptical cross section 104 fiber-reinforced thermoplastic resin composite pipe

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Claims (1)

[Claims] 1. At least three fiber-reinforced thermoplastic resin sheets are transferred in the longitudinal direction and combined into a tubular shape having a polygonal cross section corresponding to the number of the sheets, and the thermoplastic resin is tubularly formed on the inner surface of the tubular combination body. A method for producing a fiber-reinforced thermoplastic resin composite pipe, which comprises extruding and laminating to form a tubular shape having a polygonal cross section, and shaping the tubular body into a tubular shape having a circular or elliptical cross section by an internal pressure.