JPH08323882A - Manufacture of fiber-reinforced thermosetting resin composite pipe - Google Patents

Abstract

PURPOSE: To provide a manufacturing method for a fiber-reinforced thermosetting resin composite pipe, hardly rolling a void into an interface and never generating the separation of interface even when the pipe is used for a long period of time while excellent in the dimensional accuracy of the inner and outer diameters as well as the thickness thereof. CONSTITUTION: A multi-layer tube type body is formed by winding a belt type body A2, in which thermosetting resin is retained by continuous fibers arranged lengthwisely, around an extrusion molded thermosetting resin tube B2 in the circumferential direction substantially to laminate fiber-reinforced thermosetting resin layers while the multi-layer tubular body is heated under the atmospheric conditions of pressurization of inside atmosphere or evacuation of outside atmosphere or both of them to weld the thermosetting resin tube to the fiber reinforced thermosetting resin layers by fusion and, thereafter, they are integrated and fixed. The extrusion molded thermosetting resin tube B2 is cooled and solidified once, then, the belt type body A2 is wound around the thermosetting resin tube B2 under a condition that the tension of 100-5,000gr/cm<2> is retained.

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 piping for transporting fluids such as water and gas, piping used for electrical wiring, structural members, and the like.

In the fiber-reinforced composite pipe, for example, a reinforcing fiber in which a liquid thermosetting resin is impregnated around a thermoplastic resin pipe as an inner layer is wound around a mandrel, the thermosetting resin is hardened, and then the mandrel is set. 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 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 multilayer tubular body is exposed to pressure under the atmosphere inside the multilayer tubular body or depressurized under the outside atmosphere, or both, and the multilayer tubular body is heated to form a tube made of a thermoplastic resin and a fiber-reinforced resin composite. A method of firmly fusing and integrating has been proposed. In this case, after wrapping the fiber reinforced composite material around the tube made of the thermoplastic resin of the inner layer, the lamination pressure of the interfacial fusion is applied by pressurization or depressurization and the fusion is performed by only the heating method. The nature is improving.

[0007]

However, in the case of this method, the resulting fiber-reinforced thermoplastic resin composite pipe entraps air (voids) during winding, which may result in long-term cooling or under severe conditions. When used for a long period of time, the interface between the thermoplastic resin tube that is the inner layer and the fiber-reinforced resin composite wound around it peels off, or when fusing, there is a line of winding on the inner surface of the thermoplastic resin tube of the inner layer. There is a problem with the inner and outer diameters of the pipe and the accuracy of the wall thickness.

The present invention solves the above-mentioned problems of the prior art, prevents the inclusion of voids in the interface, does not cause interfacial peeling even after long-term use, and is excellent in dimensional accuracy of inner and outer diameters and wall thicknesses. The purpose of the present invention is to provide a method for producing a plastic resin composite pipe.

[0009]

DISCLOSURE OF THE INVENTION According to the present invention, a strip-shaped body in which a thermoplastic resin is held by continuous fibers arranged in the longitudinal direction is wound around an extruded thermoplastic resin tube in a substantially circumferential direction to form a fiber. A multilayered tubular body is formed by laminating a reinforced thermoplastic resin layer, and the multilayered tubular body is heated under atmospheric conditions of either pressurization of the inner atmosphere of the multilayered tubular body or depressurization of the outer atmosphere, or both, In a method for producing a fiber-reinforced thermoplastic resin composite pipe in which a thermoplastic resin pipe and a fiber-reinforced thermoplastic resin layer are fused and then integrally solidified, the extruded thermoplastic resin pipe is once cooled and solidified, and the thermoplastic resin pipe Around 1
It is a method for producing a fiber-reinforced thermoplastic resin composite pipe in which the band-shaped body is wound while maintaining a tension of 00 to 5,000 gf / cm ² .

In the present invention, the form of the strip is as follows.
A tape shape is generally used because it can be easily wound, but a string shape can be used depending on the case. The tension of the strip wound around the thermoplastic resin tube in the cooled and solidified state is 10
Must be 0-5,000 gf / cm, 300-
It is preferably 3,000 gf / cm. Tension is 10
When it is less than 0 gf / cm, when the strip-shaped body is wound around the thermoplastic resin tube, the strip-shaped body cannot be tightly adhered to the periphery of the thermoplastic resin tube without a gap, and loosening occurs and the vite enters. It is not easy to eliminate the cause of interfacial peeling, and when it exceeds 5,000 gf / cm, the winding force becomes too large, the thermoplastic resin tube is deformed, and molding itself becomes impossible.

The unit of tension: gf / 1 cm indicates the tension per 1 cm width of the tape when the strip is tape-like, and the tension per diameter 1 cm width when it is string-like. Show. For example, when a tape-shaped strip having a tape width of 2 cm is wound around a thermoplastic resin tube at 4,000 gf, the tension is 2,000 gf / cm. Further, in the case of winding a strip-shaped body of another form, the tension is based on the longest distance (width) of the cross section of the strip-shaped body to be wound.

As a method of applying tension to the strip,
A known method such as a mechanical brake or an electromagnetic brake can be appropriately adopted.

The material of the thermoplastic resin forming the thermoplastic resin tube used in the present invention is not particularly limited as long as it can be extruded into a tubular shape. Vinyl, chlorinated polyvinyl chloride, polyethylene, polypropylene, polystyrene,
Examples thereof include polyamide, polycarbonate, polyphenylene sulfide, polyether ether ketone, and the like.
These thermoplastic resins may be used alone or 2
You may use together 1 or more types.

If necessary, a heat stabilizer, a plasticizer, a lubricant, an antioxidant, an ultraviolet absorber, a pigment, an inorganic filler, a processing aid, a modifier, etc. are added to the thermoplastic resin. Good.

In the present invention, examples of the material of the continuous fibers forming the strip 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 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.

As the thermoplastic resin forming the strip,
It can be used without particular limitation as long as it has a good fusion property with the thermoplastic resin forming the thermoplastic resin tube, and the same thermoplastic resin as the thermoplastic resin forming the thermoplastic resin tube. Is preferably used.

The term "fusing property" as used herein means that both thermoplastic resins are heated to a molten state and then pressure-bonded, and after cooling, the fused interface is not easily broken.

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.

A continuous fiber similar to the above is 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 fiber 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 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.

In the present invention, the temperature at which the extruded thermoplastic resin tube is once cooled and solidified does not necessarily have to be cooled to the room temperature level, and may be a temperature not higher than the softening temperature of the thermoplastic resin.

In the present invention, the temperature at which the multilayer tubular body is heated is set to the thermoplastic resin forming the thermoplastic resin tube,
And the range from the Vicat softening temperature to the thermal decomposition temperature of the thermoplastic resin forming the strip, and particularly preferably around the molding temperature during extrusion molding of the thermoplastic resin pipe.

The pressure of the inner atmosphere of the multilayer tubular body is preferably set appropriately depending on the outer diameter and the wall thickness of the multilayer tubular body, but the range is usually 0.01 to 10 kg / cm.
² is preferred. If the applied pressure is less than 0.01 kg / cm ² , a sufficient lamination pressure cannot be obtained, and the effect of pressurization is small,
When it exceeds 101 kg / cm ² , the obtained multilayer tubular body is easily distorted and the dimensional accuracy is deteriorated. For example, when the inner diameter of the multilayer tubular body is 25 mm and the wall thickness is 3.5 mm, the applied pressure is preferably 0.01 to 3 kg / cm ² .

The depressurizing force of the outer atmosphere of the multilayer tubular body is 50.
0 mmHg or more is preferable. If the decompression force is less than 500 mmHg, a sufficient lamination pressure cannot be obtained. Further, when heating is performed while both pressurizing the inner atmosphere and depressurizing the outer atmosphere of the multilayer tubular body, the fusion property between the layers of the multilayer tubular body is further improved.

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. First, the manufacturing apparatus will be described. The manufacturing apparatus is an extruder 1 for extruding a thermoplastic resin tube.
An extrusion die 2 attached to the tip of the extruder 1, a first sizing device 3, and a decompression pump 4 used therefor,
For winding the rewinding rolls 5 and 5 on which the sheet-shaped strips A1 arranged above and below the downstream side of the first sizing device 3 are mounted, the cylindrical mold 6, and the tape-shaped strip A2. A winding device 7, a decompression heating furnace 8, a decompression pump 10 for sucking a reduced pressure in the heating furnace, a second sizing device 11, and a take-up machine 12 are sequentially arranged.

Next, the steps of an example of the present invention using this manufacturing apparatus will be described. The thermoplastic resin is kneaded in the extruder 1 and extruded in a molten state into a tubular form from the extrusion die 2, and this is passed through the first sizing device 3 having both the pressure reducing function and the cooling function, and the inner surface Vacuum suction is performed through the suction holes, while the thermoplastic resin B is brought into close contact with the inner surface of the first sizing device 3, cooling water is passed through the inside of the first sizing device 3 for cooling, and is then cooled and solidified. Thus, the thermoplastic resin tube B1 is continuously formed. On this occasion,
It is not necessary to completely cool the thermoplastic resin tube B1, but it is sufficient to cool the thermoplastic resin tube B1 to a softening temperature or lower at which the shape of the tube does not deform.

Subsequently, from above and below the thermoplastic resin tube B1, two continuous sheet fibers A1 and A1 are laminated around the thermoplastic resin tube B1 so that the continuous fibers are along the axial direction. By passing the inside of the cylindrical mold 6,
A two-layer tubular body B2 in which a first fiber-reinforced thermoplastic resin layer is formed around the thermoplastic resin tube B1 is formed.

Around the two-layer tubular body B2, a tape-shaped strip A2 in which thermoplastic resin is held by continuous fibers arranged in the longitudinal direction is applied in a substantially circumferential direction while applying tension by a winding device 7. Wrap the second layer around the two-layer tubular body B1
A three-layer tube B3 in which the fiber-reinforced thermoplastic resin layer of is laminated is formed.

The three-layer tubular body B3 is introduced into the decompression heating furnace 8 and sucked under reduced pressure by the decompression pump 10 while being heated by the heating device 9 attached to the outer surface of the three-layer tubular body B3.
Becomes a softened state, and the interface of each layer is fused by the expansion pressure (laminating pressure) generated by vacuum suction.

This three-layer tubular body B3 is passed through the inside of the second sizing device 11 for cooling. Second sizing device 1
As No. 1, a sizing device including a cooling water tank is generally used, but the present invention is not limited to this. The above-described series of steps is carried out while being taken by the take-up machine 12, and although not particularly shown, the fiber-reinforced thermoplastic resin composite pipe C is continuously manufactured by cutting it into an appropriate length. 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. 2 is a partially cutaway perspective view showing the fiber reinforced thermoplastic resin composite pipe C thus obtained. In the fiber-reinforced thermoplastic resin composite pipe C, a first fiber-reinforced thermoplastic resin layer C2 in which continuous fibers are arranged along an axial direction which is an intermediate layer is laminated around a thermoplastic resin pipe C1 which is an inner layer. A second fiber-reinforced thermoplastic resin layer C3, in which continuous fibers are arranged as an outer layer along the substantially circumferential direction, is laminated and integrated around it.

[0035]

The method for producing a fiber-reinforced thermoplastic resin composite pipe of the present invention is such that the extruded thermoplastic resin pipe is once cooled and solidified,
100-5000 gf / c around the thermoplastic tube
By winding the band-shaped body while maintaining the m ² tension, it is difficult for voids to be caught in the interface, the thermoplastic resin tube is not deformed by the winding force, and the interfacial peeling hardly occurs even when used for a long period of time. It is possible to obtain a fiber-reinforced thermoplastic resin composite pipe excellent in dimensional accuracy of inner and outer diameters and wall thickness.

[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 a powdered polyvinyl chloride resin (Tokuyama Sekisuisha). Product name "TS-10"
00R ", Vicat softening point: about 80 ° C) to pass a powdered polyvinyl chloride resin between the fibers and heat it with a pair of heating rolls heated to about 200 ° C. A sheet-shaped strip A in which a thermoplastic resin is held by continuous fibers arranged in the longitudinal direction by pressing.
1 (width 170 mm, thickness 0.5 mm) and tape-shaped strip A2 (width 40 mm, thickness 0.5 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. The sheet-shaped strips A1 and A1 were mounted on the rewinding rolls 5 and 5, and the tape-shaped strip A2 was mounted on the winding device 7.

First, polyvinyl chloride resin (manufactured by Tokuyama Sekisui company, trade name "TS-1000", Vicat softening point: about 8)
(0 ° C.) is kneaded by the extruder 1 and extruded in a molten state in a tubular form from the extrusion die 2, and the inside of the first sizing device 3 having an inner diameter of 111 mm is decompressed by the decompression pump 4 from the suction hole on the inner surface to 70 ° C.
It was sucked with a decompression force of 0 mmHg, brought into close contact with the inner surface thereof, and allowed to pass while being water-cooled to continuously form a thermoplastic resin tube B1 having an outer diameter of 111.2 mm.

Subsequently, from above and below the thermoplastic resin tube B1, two continuous sheet fibers A1 and A1 are laminated around the thermoplastic resin tube B1 so that the continuous fibers are along the axial direction. Was passed through the cylindrical mold 6 to form a first fiber-reinforced thermoplastic resin layer around the thermoplastic resin tube B1 to form a two-layer tubular body B2 having an outer diameter of 112 mm. At this time, the temperature of the two-layer tubular body B2 was about 50 ° C.

A tape-shaped strip A2 is wound around the two-layer tubular body B2 in a substantially circumferential direction while applying tension by a winding device 7, and a second fiber-reinforced thermoplastic resin is wound around the two-layer tubular body B2. A three-layer tubular body B3 in which resin layers were laminated was formed.
When the tension at this time was measured with a tension meter (manufactured by Shinpo Kogyo KK), it was 1,500 gf / cm.

This three-layer tubular body B3 is introduced into the vacuum heating furnace 8 and is vacuum-sucked by the vacuum pump 10 with a vacuum pressure of 700 mmHg, while being heated to 350 ° C. by the heating device 9 mounted on the outer surface, the three-layer tubular body B3 is heated. The tubular body B3 was in a softened state, and the interfaces of the respective layers were fused by the expansion pressure (laminating pressure) generated by vacuum suction. At this time, the temperature of the three-layer tubular body B3 was 175 ° C., and the resin did not decompose.

This three-layer tubular body B3 is passed through the inside of the second sizing device 11 to be water-cooled, and a series of these steps is carried out while being taken by the take-up machine 12, cut into an appropriate length, and then, as shown in FIG.
A fiber reinforced thermoplastic resin composite pipe C as shown in (1) was obtained.

When the interface of the cross section of the obtained fiber-reinforced thermoplastic resin composite pipe C was observed, no void was observed, the interface was firmly fused, and the outer diameter was 114.0 ± 0.05 m.
m, the inner diameter was 100.0 ± 0.05 mm, and there were few dimensional variations.

Example 2 A tape-shaped strip A2 having a width of 35 mm and a thickness of 0.7 m
m, a fiber content of 25% by weight, a winding tension of the tape-shaped strip A2 of 700 gf / cm, a decompression heating furnace temperature of 340 ° C., and a decompression force of 68.
A fiber-reinforced thermoplastic resin composite pipe C was obtained in the same manner as in the example except that the pressure was 0 mmHg, the temperature of the three-layer tubular body B3 was 180 ° C., and the resin did not decompose.

When the interface of the cross section of the obtained fiber reinforced thermoplastic resin composite pipe C was observed, no void was observed, the interface was firmly fused, and the outer diameter was 114.0 ± 0.05 m.
m, the inner diameter was 100.0 ± 0.05 mm, and there were few dimensional variations.

Comparative Example 1 A fiber-reinforced thermoplastic resin composite pipe C was obtained in the same manner as in Example 1 except that tension was not applied when the tape-shaped strip A2 was wound. Obtained fiber-reinforced thermoplastic resin composite pipe C
When observing the interface of the cross section, many voids were seen, the outer diameter was 114.0 ± 0.4 mm, and the inner diameter was 100.0.
There was a large variation of ± 0.4 mm.

Comparative Example 2 The tension when the tape-shaped strip A2 was wound was 6,000 gf /
In the same manner as in Example 1 except that the pressure was set to cm, the tension was too strong and the thermoplastic resin tube of the inner layer was deformed,
The fiber reinforced thermoplastic resin composite pipe C could not be obtained.

Each of the five fiber-reinforced thermoplastic resin composite pipes C obtained in Examples 1 and 2 and Comparative Example 1 was subjected to a cold heat repeating test to observe the peeling condition of the interfaces at both ends. The results are shown in Table 1. In addition, as the cold heat condition,
85 ° C / 25 ° C = 5 minutes / 5 minutes as one cycle, water pressure of 1.5 Kg / cm ² , 2,000 cycles, 5,0
It was set to 00 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.

[0050]

[Table 1]

As described above, the fiber-reinforced thermoplastic resin composite pipes obtained according to the examples of the present invention have excellent dimensional accuracy without peeling of the interface even after long-term use.

[0052]

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, it is difficult for voids to be caught in the interface, and there is almost no interfacial peeling even when used for a long period of time. It is possible to obtain a fiber-reinforced thermoplastic resin composite pipe having excellent dimensional accuracy of inner and outer diameters and wall thickness.

[Brief description of 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 partially cutaway perspective view showing an example of a fiber-reinforced thermoplastic resin composite pipe obtained by the present invention.

[Explanation of reference numerals] A1 sheet-shaped strip A2 tape-shaped strip B1 thermoplastic resin tube B3 three-layer tubular body C fiber-reinforced thermoplastic resin composite tube

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

Claims (1)

[Claims] 1. Around an extruded thermoplastic resin tube,
A belt-shaped body in which a thermoplastic resin is held is wound around the continuous fibers arranged in the longitudinal direction in a substantially circumferential direction to form a multilayer tubular body by laminating a fiber-reinforced thermoplastic resin layer, and the inner atmosphere of the multilayer tubular body is formed. A fiber reinforced thermoplastic resin that heats a multilayer tubular body under either or both of pressurized conditions and depressurized outside atmospheres to fuse the thermoplastic resin tube and the fiber reinforced thermoplastic resin layer and then solidify them integrally. In the method for producing a composite pipe, the extruded thermoplastic resin pipe is once cooled and solidified, and 100 to 5,000 gf / c around the thermoplastic resin pipe.
A method for producing a fiber-reinforced thermoplastic resin composite pipe, which comprises winding the belt-shaped body while maintaining a tension of m ² .