JPH04201548A - Manufacture of fiber reinforced resin pipe - Google Patents

Abstract

PURPOSE:To prevent ease of separation on the interface of each layer, while the linear expansion of a pipe is suppressed and the amount of thermal shrinkage is reduced by arranging continuous reinforcing fibers on a first reinforcing layer in the axial direction of the pipe. CONSTITUTION:A tubular object A2 is continuously formed of the sheetlike fiber composite A1 for a first reinforcing layer made by holding thermoplastic resin on the continuous reinforcing fiber arranged in longitudinal direction. Next after a molten resin layer B2 has been formed on the inner surface of said tubular object A2, the temperature of the molten resin layer B2 is lowered to at most the softening temperature thereof, and the thermoplastic resin inner layer B3 which has the first reinforcing layer 3 in which reinforcing fiber is arranged in axial direction, is formed as the pipe of two layers. While the fiber composite C1 for a second reinforcing layer made by holding thermoplastic resin on the continuous reinforcing fiber arranged in longitudinal direction, is spirally wound on the outer periphery of the pipe of two layers, it is welded to the first reinforcing layer A3, and a second reinforcing layer C2 in which reinforcing fiber is arranged almost in peripheral direction, is formed on the outer surface of the first reinforcing layer A3 as the pipe of three layers, thereby obtaining a desired fiber reinforced resin pipe E.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a fiber-reinforced resin pipe.

[Conventional technology]

Synthetic resin pipes have been widely used since they have superior properties such as being lighter and less rusty than metal pipes. However, synthetic resin pipes are inferior to metal pipes in pressure resistance and impact resistance. Therefore, in order to solve this problem, we developed a composite tube with a thermosetting resin reinforcing layer in which continuous reinforcing fibers are arranged in the longitudinal direction of the tube on the outer surface of the thermoplastic resin tube, and a composite tube with continuous reinforcing fibers on the outer surface of the thermoplastic resin tube. A composite pipe has been proposed in which a thermosetting resin reinforced layer is formed which is arranged approximately in the circumferential direction of the pipe (Japanese Patent Publication No. 62-773, Japanese Patent Application Publication No. 57-100030, and Japanese Patent Application Publication No. 59-4812).
(See Publication No. 0).

The above composite pipe has excellent pressure resistance and impact resistance. In particular, pipes in which continuous reinforcing fibers are arranged in the axial direction of the pipe have four advantages in that the heat shrinkage of the pipe is small and there are fewer troubles caused by heat shrinkage of the pipe in the piping line.

[Problem to be solved by the invention]

However, since the reinforcing layer of the above composite pipe is made of thermosetting resin, its adhesion to the inner thermoplastic resin layer is weak, and when hot water is poured into the composite pipe or used at high temperatures, the thermoplastic resin layer may There has been a problem in that peeling is likely to occur at the interface between the thermoplastic resin layer and the reinforcing layer due to the difference in linear expansion coefficient with the reinforcing layer.

An object of the present invention is to provide a method for manufacturing fiber-reinforced resin pipes that have excellent pressure resistance and impact resistance, and can be easily and continuously rolled without causing any problems even when running hot water or using them at high temperatures. It's about doing.

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a fiber reinforced resin pipe according to the present invention provides a method for manufacturing a fiber reinforced resin pipe in which a thermoplastic resin is held in continuous reinforcing fibers arranged in the longitudinal direction. A process of continuously molding a tubular body from a sheet-like fiber composite for the reinforcing layer, and extruding the thermoplastic resin for the inner layer in a molten state along the inner surface of the tubular body while advancing the tubular body that is sequentially molded. After forming a molten resin layer, the molten resin layer is cooled below its softening temperature to form a thermoplastic resin inner layer having a first reinforcing layer in which reinforcing fibers are arranged in the axial direction, thereby forming a two-layer pipe. The second reinforcing layer tape-like or string-like fiber composite, in which thermoplastic resin is held by continuous reinforcing fibers arranged in the longitudinal direction, is spirally formed around the outer periphery of the two-layer pipe while advancing as it is. Wrapping and fusing this to the first reinforcing layer to form a second reinforcing layer in which reinforcing fibers are arranged approximately circumferentially on the outer surface of the first reinforcing layer to form a three-layer pipe. It is characterized by:

The reinforcing fibers used in the first and second reinforcing layers include:
All continuous fibers available for reinforcing thermoplastics may be used. Specifically, glass fiber, carbon fiber,
Examples include inorganic fibers such as silicone, titanium, carbon fibers, boron fibers, and fine metal fibers, and organic fibers such as aramid fibers, vinylon fibers, econol fibers, polyester fibers, and polyamide fibers.

The continuous reinforcing fibers used are roving-like or strand-like continuous filaments having a diameter of 1 to several tens of micrometers. The reinforcing fiber for the first reinforcing layer and the second reinforcing fiber
The reinforcing fibers for the reinforcing layer may be of the same type or different types.

In addition, the continuous reinforcing fibers are arranged in the longitudinal direction of both the side fiber composites, but in the case of the sheet-like fiber composite for the first reinforcing layer, the continuous reinforcing fibers are arranged at right angles or intersecting with the continuous reinforcing fibers arranged in the longitudinal direction. Continuous reinforcing fibers or fibers of finite length may be arranged, or cross-like fibers or net-like fibers made of fibers of finite length may be arranged.

In the case of the tape-shaped fiber composite for the second reinforcing layer, in addition to the continuous reinforcing fibers arranged in the longitudinal direction, the same finite length fibers as described above may be included.

The thermoplastic resin for the inner layer is not particularly limited as long as it can be extruded into a tubular shape, but specific examples include polyvinyl chloride, chlorinated polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyamide, polycarbonate, and polyphenylene sulfide. , polysulfone,
Examples include polyetheretherketone.

These thermoplastic resins can be used alone or in a mixture depending on the intended use of the pipe. The thermoplastic resin is blended with additives such as heat stabilizers, plasticizers, lubricants, antioxidants, ultraviolet absorbers, pigments, reinforcing fibers, inorganic fillers, processing aids, modifiers, etc. , but that's fine.

The thermoplastic resin for the first and second reinforcing layers does not necessarily have to be the same as the thermoplastic resin for the inner layer, and any thermoplastic resin with good fusion properties may be used.

However, it is preferable that the thermoplastic resin of the second reinforcing layer has a greater fusing property with the thermoplastic resin for the first reinforcing layer, which is in direct contact with it, than with the thermoplastic resin for the inner layer. By doing so, the interlayer adhesion between the first reinforcing layer and the second reinforcing layer becomes high, and an excellent fiber-reinforced resin pipe can be obtained. Note that the fusion property here refers to the fact that both resins are heated until they are in a molten state and then pressed together, and that the fused interface does not easily break after cooling.

The width of the sheet-like fiber composite for the first reinforcing layer is approximately equal to the outer circumferential length of the tubular body formed from it, and the thickness is determined depending on the desired thickness of the first reinforcing layer, but usually 0.
1n+m to 3■. Further, the amount of fibers in the sheet-like fiber composite is 5 to 70% by volume. If it is less than 5% by volume, a sufficient reinforcing effect cannot be obtained, and if it exceeds 70% by volume, the fusion properties between the thermoplastic resin inner layer and the second reinforcing layer will decrease and the interface will not be sufficiently fused.

The width and thickness of the fiber composite for the second reinforcing layer are not particularly limited, but in the case of a tape-shaped fiber composite, the width is 10 to 1
00 l1ls Thickness of 0.11 to 3I is used. Moreover, in the case of a string shape, one having a diameter of about 0.5 to 5 m11 is used.

In order to fuse the tape-like or string-like fiber composite for the second reinforcing layer to the first reinforcing layer, one or more tape-like or string-like fiber composites for the second reinforcing layer can be heated and wound around the first reinforcing layer, or after being wrapped, is heated together with the first reinforcing layer to fuse both thermoplastic resins together. When using multiple tape-shaped or string-shaped fiber composites, they may all be wound in the same direction, each wrapped at a different winding angle, or even the winding direction may be changed. .

The method for retaining thermoplastic resin in continuous reinforcing fibers is to (i) pass continuous reinforcing fibers in the form of a roving or strand bundle consisting of a large number of filaments through a fluidized bed of powdered thermoplastic resin; i i) Impregnating the filaments with the powdered thermoplastic resin by passing it through a bath of liquid in which the powdered thermoplastic resin is dispersed, and then heating it above the melting temperature to integrate the fiber and resin. , or after impregnating with resin, dry it, then heat it above the melting temperature to integrate the fiber and resin, and then form a sheet,
A method of forming it into a tape or string shape is adopted. In the case of a resin having a low melt viscosity, it is also possible to immerse the bundled continuous reinforcing fibers in a bath of molten resin to impregnate it with the resin.

A thermoplastic resin outer layer may be further provided on the outer surface of the second reinforcing layer. In this case, there are no particular restrictions on the thermoplastic resin used for the outer layer, and any thermoplastic resin can be used, or of course, a thermoplastic resin that has good fusion properties with the thermoplastic resin used for the second reinforcing layer may be used. It is preferable to use

[Function] The method for manufacturing a fiber-reinforced resin pipe according to the present invention involves continuously forming a tubular body from a sheet-like fiber composite for a first reinforcing layer in which a thermoplastic resin is held in continuous reinforcing fibers arranged in the longitudinal direction. The thermoplastic resin for the inner layer is extruded in a molten state along the inner surface of the tubular body as it is molded and the tubular body is successively molded.
After forming a molten resin layer on the inner surface of the tubular body, the molten resin layer is cooled to a temperature below its softening temperature to form a thermoplastic resin inner layer having a first reinforcing layer in which reinforcing fibers are arranged in the axial direction. While the two-layer pipe is advanced as it is, a tape-like or string-like fiber composite for the second reinforcing layer, in which thermoplastic resin is held by continuous reinforcing fibers arranged in the longitudinal direction, is spirally attached to the outer periphery of the two-layer pipe. A three-layer pipe is formed by winding the reinforcing layer into a shape, fusing it to the first reinforcing layer, and forming a second reinforcing layer in which reinforcing fibers are arranged approximately in the circumferential direction on the outer surface of the first reinforcing layer. From there, the thermoplastic resin is sequentially and continuously fused and integrated at the boundaries of the inner layer, the first reinforcing layer, and the second reinforcing layer. Moreover, as mentioned above, after the molten resin layer formed by extruding the thermoplastic resin for the inner layer in a molten state along the inner surface of the tubular body is cooled to below its softening temperature, a layer is formed on the outer periphery of the two-layer tube. Since the tape-like or string-like fiber composite for the second reinforcing layer is wound in a spiral shape and is fused to the first reinforcing layer,
No unevenness in pipe thickness.

〔Example〕

First, an apparatus used to carry out the present invention will be explained with reference to the drawings. In the following description, the term "front" refers to the right direction in FIG.

The apparatus for manufacturing a fiber-reinforced resin pipe shown in FIGS. 1 to 3 includes an unwinding roll (1) around which a sheet-like fiber composite for a first reinforcing layer (A1) is wound, and an unwinding roll (1) disposed in front of the unwinding roll (1). and a first extruder (3) for extruding an inner layer thermoplastic resin, the tip of which is bent forward at a right angle and whose outer periphery is an inner mold (2) with a circular cross section; a heating means (4) disposed on the rear side of the body, a pair of drum-shaped forming rolls (5) sandwiching the inner mold (2) from both sides, and the tip of the first extruder (3). A core (6) having a protrusion (6a) provided at the axis of the inner mold (2) and protruding forward from the inner mold (2).
and the protrusion of the core (6) from the tip of the inner mold (2) (
6a); and a cooling mold (9) placed in front of and concentrically with the outer mold (7) via a heat insulating material (8). A winding machine for the tape-shaped fiber composite (C1) is placed in front of the cooling mold (9)
10), a heating means (11) disposed on one side of the wrapping position, a second extruder (12) for extruding the outer layer thermoplastic resin disposed in front of the heating means (11), a covering mold (13) provided concentrically with the cooling mold (9) at the tip of the second extruder (12); a cooling device (14) disposed in front of the covering mold (13); It is equipped with a take-up machine (15) placed in front of the cooling device (14).

A gap corresponding to the thickness of the tubular body (A2) to be formed is provided between the inner mold (2) and the pair of drum-shaped forming rolls (5). The inner mold inner part (6b) of the core (6) has a small diameter, becomes thicker in an inverted conical shape near the tip of the inner mold (2), and becomes a large diameter columnar shape at the protrusion (6a). . Between this protruding part (6a) and the tubular body A2), there is a thickness of the tubular molten resin layer (B2) formed by the molten resin (Bl) extruded from the first presser 8 (3). A gap is provided.

Figure 4 shows how the sheet fiber composite (A1) is separated from the tubular body A.
2), instead of using a pair of shaping rolls (5), the outer mold (27) is extended rearward from the outer mold (7) to form the entire inner mold (2). A modification example in which it is covered is shown.

The sheet-like fiber composite (A1) and tape-like fiber composite (C1) are manufactured using a fluidized bed apparatus (16) shown in FIG. 5.

The tank bottom of this fluidized bed apparatus (IB) is formed by a perforated plate (17), and gas (G) such as air or nitrogen sent from the gas supply path is passed through from below the perforated plate (17). It is forced to eject upward through numerous holes. As a result, the powdered thermoplastic resin placed in the tank of the fluidized bed device (16) is brought into a fluidized state by the ejected gas (G), and a fluidized bed (1?) is formed. Guide rolls (18) for guiding bundled reinforcing fibers are provided in the tank of the fluidized bed device (16) and at the upper ends of its front and rear walls.

Using the above fluidized bed device (16), unwind roll (■9)
Bundled reinforcing fibers (P
I) The 10 fibers are rewound using a winding roll (20) while being careful not to twist, and passed through a fluidized bed (R) of powdered thermoplastic resin to separate each filament of the bundled reinforcing fibers (Fl). Attach powdered resin to. As the powdered thermoplastic resin, vinyl acetate-vinyl chloride copolymer (8% vinyl acetate amount, average particle size 250 μm) was used, and as the reinforcing fiber, roving glass fiber (4400 tex) consisting of filaments with a diameter of 23 μm was used. Using.

Powdered thermoplastic resin-adhered reinforcing fiber (F2) at approximately 180℃
The thermoplastic resin is heated and pressurized by passing through a pair of heating rolls (21) heated to The fiber composite (F3) had a volume ratio of thermoplastic resin and reinforcing fibers of 75% thermoplastic resin and 25% reinforcing fibers.

The above fiber composite (B3) was cut to obtain a sheet-like fiber composite (A1) with a width of 911111% and a thickness of 0.6 mm, in which continuous reinforcing fibers were arranged in the longitudinal direction. width 23.5III11. A tape-shaped fiber composite (C1) having a thickness of 0°61 was obtained.

The sheet-like fiber composite for the first reinforcing layer (A1) produced as described above is transferred to the unwinding roll' (1) shown in FIG. The sheet-like fiber composite for the first reinforcing layer (A1) is heated by blowing hot air using a machine, and then both edges of the sheet-like fiber composite for the first reinforcing layer (A1) are brought together and the outer diameter is 2゛9■, thickness 0,
Continuously mold into a 6-inch tubular body (A2).

The tubular body (A2) is introduced into the annular gap between the inner mold (2) and the protrusion (6a) of the core (6) and the outer mold (7). The inner mold (2), core (6) and outer mold (7) are heated to 200°C.

The thermoplastic resin for the inner layer (B1) is extruded in a molten state from the first extruder (3) along the inner surface of the tubular body (A2) that is being formed sequentially, and is melted onto the inner surface of the tubular body (A2). After forming the resin layer (B2), it is introduced into a cooling mold (9) at 79°C, and the molten resin layer (B2) is cooled to its softening temperature of 79°C, so that reinforcing fibers are arranged in the axial direction. By forming a thermoplastic resin inner layer (B3) with a thickness of 1.5 layers and 1 m having a first reinforcing layer (83), a two-layer pipe with an outer diameter of 29 cm was obtained.

As the thermoplastic resin for the inner layer (B1), chlorinated polyvinyl chloride (degree of chlorination: 64% by weight) was used.

While the two-layer pipe is being moved forward, a winding machine (l
O), the tape-shaped fiber composite for the second reinforcing layer (C1) is wound in a spiral shape at an angle of 75'' to the axial direction, and the infrared heater serving as the heating means (11) is used to wrap the two-layer tube and the tape. The shaped fiber composite (C1) is heated and the latter is fused to the first reinforcing layer (83) to form the first reinforcing layer (A3).
A second reinforcing layer (C2
) to form a three-layer pipe.

The three-layer tube is guided into the coating mold (13), and the second extruder (12)
The thermoplastic resin for the outer layer, which has been melted and plasticized by
After forming the thermoplastic resin outer layer (D) of l11, it is cooled and sized using a cooling device (14) to form a four-layer tube. Polyvinyl chloride was used as the thermoplastic resin for the outer layer. The above series of steps are carried out while being picked up by a picking machine (15),
Internal diameter 24.8 made of 4-layer composite pipe as shown in Figure 6
Fiber-reinforced resin pipes (E) with a diameter of +nm and an outer diameter of 32.2 mm were continuously manufactured.

In the above, instead of providing the heating means (4), a heater may be built into the pair of shaping rolls (5) and heated to a temperature higher than the softening temperature of the sheet-like fiber composite (A1). .

In addition, when wrapping the tape-like fiber composite (C1) around the outer periphery of the two-layer pipe, in order to prevent the two-layer pipe from deforming, the core (
The protrusion (6a) of 6) may be made to protrude as far as the winding position, or cooling air may be blown into the inside of the two-layer tube from the tip of the core (6) while cooling the inner surface of the two-layer tube. A tape-shaped fiber composite (C1) may be wound around it.

Moreover, a cold air blower may be used instead of the cooling mold (9).

Further, although a water tank is generally used as a cooling device (14) for performing cooling sizing, it is not limited to this.

Note that the position of the heating means (4) is not limited to the location shown in the figure, and it may be omitted depending on the case.

〔Effect of the invention〕

According to this invention, the thermoplastic resin is sequentially and continuously fused and integrated at each boundary of the inner layer, the first reinforcing layer, and the second reinforcing layer, and a fiber-reinforced resin pipe with an even thickness can be easily and continuously formed. You can wander around.

Since the first reinforcing layer of the obtained fiber-reinforced resin pipe has continuous reinforcing fibers arranged in the axial direction of the pipe, the linear expansion of the pipe is suppressed, and as a result, the amount of thermal contraction is reduced and each layer Peeling at the interface is less likely to occur. Further, since the second reinforcing layer includes continuous reinforcing fibers arranged approximately in the circumferential direction of the tube, the second reinforcing layer improves the pressure resistance and impact resistance of the tube.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view of a manufacturing apparatus for fiber reinforced resin pipes used in carrying out the present invention, and FIGS. 2 and 3 are cross-sectional views taken along the lines 4 is a partially cutaway plan view showing a modified example of the tubular body molded part, FIGS. 5 and 5 are vertical sectional views of the fluidized bed apparatus, and FIG. FIG. 3 is a partial perspective view of the tube in which the outer layer, the second reinforcing layer and the first reinforcing layer are successively cut away. (A1)...Sheet-like fiber composite for first reinforcing layer, (A
2)... Tubular body, (A3)... First reinforcing layer, (B1
)...Thermoplastic resin for inner layer, (B2)... Molten resin layer, (B3)... Thermoplastic resin inner layer, (C1)...
Tape-shaped fiber composite for second reinforcing layer, (C2)...second
reinforcement layer. Patent applicant: Sekisui Chemical Co., Ltd.

Claims (1)

[Scope of Claims] a) A sheet-like fiber composite for the first reinforcing layer (A1
b) extruding the thermoplastic resin for the inner layer (B1) in a molten state along the inner surface of the tubular body (A2) while advancing the tubular body (A2) that has been sequentially molded; A molten resin layer (B2) is formed on the inner surface of the tubular body (A2).
), the molten resin layer (B2) is cooled to below its softening temperature to form a first reinforcing layer (B2) in which reinforcing fibers are arranged in the axial direction.
A3) forming a two-layer tube by forming a thermoplastic resin inner layer (B3) having A tape-like or string-like fiber composite for the second reinforcing layer in which resin is retained (C
1) is spirally wound and fused to the first reinforcing layer (A3) to form a second reinforcing layer (C2) in which reinforcing fibers are arranged approximately circumferentially on the outer surface of the first reinforcing layer (A3). A method for manufacturing a fiber-reinforced resin pipe, comprising the step of forming a three-layer pipe by forming a three-layer pipe.