JPH0321435A - Manufacture of composite pipe - Google Patents

Abstract

PURPOSE:To surroundingly and strongly fuse reinforcing fiber round the outer periphery of pipe by a method wherein cooling medium is passed through the inside pipe line of thermoplastic resin pipe and prepreg is fusion-bonded onto the outer periphery of the thermoplastic resin pipe by thermally fusing the surface of the pipe and the fusion-bonding surface of the prepreg. CONSTITUTION:A pipe 1 is rotated under the state that cooling medium 3 such as water, air or the like is passed through the inside pipe line of thermoplastic resin pipe 1. Further, by means of said rotation, string-like or tape-like prepreg 2 is wound round the outer periphery of the thermoplastic resin pipe 1. In this case, the prepreg 2 is wound on the surface of the thermoplastic resin pipe 1 after the prepreg 2 and the surface of the thermoplastic resin pipe 1 are heated by hot air or with a heating means 4 such as far infrared heater or the like into molten state so as to fusion-bond the prepreg onto the surface of the thermoplastic resin pipe 1 in order to manufacture composite pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a composite pipe made of thermoplastic resin reinforced with reinforcing fibers.

(Prior Art) Conventionally, composite resin pipes have been widely used because they have superior properties compared to metal pipes, such as being lightweight and not rusting. However, this composite resin pipe is inferior to metal pipes in water pressure resistance and impact resistance. Therefore, composite pipes in which a fiber-reinforced thermoplastic resin layer is provided around the outer periphery of a thermoplastic resin pipe have been proposed as a way to add water pressure resistance and impact resistance to these synthetic resin pipes (for example, 63-152786). Methods for manufacturing this composite pipe include a method in which reinforcing fibers to which thermoplastic resin is attached are wound and fused around the outer periphery of a thermoplastic resin pipe while heating; There are methods such as wrapping it around the outer circumference of the vibrator and then heating and fusing it.

(Problems to be Solved by the Invention) However, in the case of the above-mentioned conventional manufacturing method, there was a problem that the thermoplastic resin pipe was easily softened and deformed by heating. Furthermore, if heating is avoided in order to prevent softening and deformation, the reinforcing fibers are insufficiently fused and the reinforcing fibers tend to peel off due to impact loads.

The present invention has been made in view of the above circumstances, and provides a method for manufacturing a composite pipe in which reinforcing fibers can be wound and firmly fused around the outer circumference of a thermoplastic resin pipe without deforming the pipe. The purpose is to

(Means for Solving the Problems) The method for manufacturing a composite pipe of the present invention uses a string-like or tape-like prepreg made of reinforcing fibers impregnated with a thermoplastic resin.
A method of fusion bonding to the outer periphery of a thermoplastic resin pipe, the method comprising passing a cooling medium through the inner conduit of the thermoplastic resin pipe, and heating and melting the surface of the pipe and at least the fusion surface of the prepreg. At the same time, the prepreg is fused to the outer periphery of the thermoplastic resin pipe.

(Function) A cooling refrigerant is passed through the inner pipe line of the thermoplastic resin pipe, and the surface of the pipe and the fusion surface of the prepreg are heated and melted, and the prepreg is fused to the outer periphery of the thermoplastic resin pipe. .

At this time, the inner pipe line of the thermoplastic resin pipe maintains its hardness without being heated by the passage of the cooling refrigerant, and only the surface of the thermoplastic resin pipe becomes molten by heating. Further, in the prepreg that is heated together with the thermoplastic resin pipe, the thermoplastic resin impregnated with reinforcing fibers becomes molten by heating.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the state of manufacture of a composite pipe.

That is, the pipe 1 is rotated while passing a cooling medium 3 such as water or air through the inner conduit of the thermoplastic resin pipe 1 . Further, by this rotation, a string-like or tape-like prepreg 2 is wound around the outer periphery of the thermoplastic resin pipe 1. At this time, the prepreg 2 is heated to a molten state by heating the surfaces of the prepreg 2 and the thermoplastic resin pipe 1 in a heating stage 4 using hot air or a far-infrared heater, and then wound around the surface of the thermoplastic resin pipe 1. do. Then, the pre-reg 2 is fused to the surface of the thermoplastic resin pipe 1,
The production of composite pipes is thereby carried out.

In order to obtain excellent watertightness, thermoplastic resin pipes are
It is preferable to use a thermoplastic resin pipe that does not contain reinforcing fibers. Further, the material thereof is not particularly limited, and polyvinyl chloride, polyethylene, polypropylene, boria ξ-d, polyphenylene sulfide, polyether ether ketone, etc. are used.

The prepreg 2 is constructed in the form of a string or tape by impregnating a reinforcing fiber roving 2a, which is a bundle of many filaments made of continuous reinforcing fibers, with a thermoplastic resin 2b.

The reinforcing fibers are preferably fibers having a heat resistance higher than the melting temperature of the thermoplastic resin 2b to be impregnated, such as glass fibers, carbon fibers, amorphous fibers, metal fibers, and the like.

Further, the thermoplastic resin 2b to be impregnated into the reinforced woven fiber roving 2a made of reinforced woven fibers is not particularly limited as long as it is a resin that can be fused to the thermoplastic resin pipe 1. In order to obtain strength, it is preferable to use a thermoplastic resin of the same type as the thermoplastic resin pipe 1 described above.

For example, when polyvinyl chloride resin is used as the thermoplastic resin pipe l, polyvinyl chloride resin, chlorinated vinyl chloride resin, vinylidene chloride, vinyl chloride-ethylene copolymer, chloropropylene copolymer, chlorinated Vinyl-vinyl acetate copolymers and the like are preferably used.

Regarding the ratio of the reinforcing fibers in the prepreg 2 to the thermoplastic resin 2b, if the amount of reinforcing fibers is less than 5% by volume, it is difficult to obtain a reinforcing effect, and if it exceeds 80% by volume, the fusion with the thermoplastic resin pipe 1 becomes difficult. Since it lacks adhesion, the amount of reinforcing fibers is appropriately determined in the range of 5 to 80% by volume.

As shown in FIG. 2, such a prepreg 2 is manufactured by attaching a powdered thermoplastic resin 2b to a reinforcing fiber roving 2a.

That is, the powdered thermoplastic resin 2b is fluidized in the fluidized bed 5 by air 6, and the reinforcing fiber roving 2a is passed through the fluidized bed 5 to form each reinforcing fiber roving 2a. Thermoplastic resin 2b is attached between the fibers. Thereafter, the reinforcing fiber roving 2a to which the thermoplastic resin 2b is attached is pressed and integrated by a pressure roll 7 to obtain a string-like or tape-like prepreg 2.

When the prepreg 2 is wound around the thermoplastic resin pipe 1, the prepreg 2 is wound in several layers at an appropriate angle with respect to the tube axis direction of the thermoplastic resin vibe 1. Then, the reinforcing fibers in the prepreg 2 cross each other and are arranged in multiple layers on the surface of the thermoplastic pipe 1, and excellent physical properties in terms of strength can be obtained. At this time, the thicknesses of the thermoplastic resin pipe 1 and the prepreg 2 are not particularly limited, but are usually appropriately selected within the range of 0.5 to 20 mm.

Next, specific examples of composite vibes will be explained in the order of ■manufacture of thermoplastic resin pipes, ■manufacture of prepreg, ■manufacture of composite pipes, and ■performance evaluation of composite pipes, and then a comparison will be made with this composite pipe. Give an example.

(First Example) ■Production Table 1 of Thermoplastic Resin Vibrator Thermoplastic resin vibrator having an outer diameter of 59 mm and a wall thickness of 4 ml was molded by extrusion molding the materials made of each combination shown in Table 1 above.

■Manufacture of pre-reg (blank below) Table 2 Materials consisting of each composition shown in Table 2 above are mixed in a super mixer to form a powder mixture, and the powder mixture is heated with air in a fluidized bed. Fluidize. Next, a roving-shaped glass fiber formed by converging a large number of monofilaments each having a diameter of 13 μm is passed through this fluidized bed, and the powdery mixture is deposited between the monofilaments. Thereafter, the powder mixture adhering to the monofilament was melted while being pressed with a heating roll at about 200°C, and the mixture was made to have a width of about 5On+, a thickness of about 0.5*+m, and a glass fiber content of 25mm.
Capacity% prepreg tape was prepared.

■Manufacture of composite pipe The thermoplastic resin pipe obtained in step (■) is rotated while passing water at approximately 20°C through the inner conduit, and as a result of this rotation, the prepreg tape obtained in step (■) is wrapped around the surface of the thermoplastic resin pipe. to fuse. At this time, the surface of the thermoplastic pipe,
Hot air at about 400° C. is blown onto the fusion surface of the prepreg tape that is in contact with the surface of the vibrator, thereby melting and fusion bonding the two. Further, the prepreg tape is wound at an angle of +75' with respect to the tube axis direction of the thermoplastic resin pipe. Next, on top of this fused prepreg tape, we fused the prepreg tape at an angle of -75° with respect to the tube axis direction of the thermoplastic resin pipe, contrary to the previous process, and the inside of the prepreg tape was fused. Let the glass fibers cross each other. Below, in the same way, +75
A composite pipe was manufactured by fusing the prepreg tape at an angle of −75°.

■Performance evaluation of composite pipe■The composite pipe obtained in ■ is one in which reinforcing fibers are arranged as a reinforcing layer around the outer periphery of a thermoplastic resin pipe that does not contain reinforcing fibers with a thickness of about 2n so that they intersect with each other. Ta. Furthermore, no deformation of the thermoplastic resin pipe serving as the inner layer was observed during manufacturing. The composite pipe obtained in step ① was cut into a 20 cm length to make a test piece, and a cylindrical iron cone with a diameter of 50 m (weighing 9 kg) was attached to the test piece of this pipe.
) was dropped from a height of 500 cm. As a result, the test piece was not damaged. In addition, when the impact part was cut and visually observed, the fused part, which is the boundary between the inner layer thermoplastic resin pipe and the reinforcing layer prepreg tape, was in a bonded state and no peeling was observed. (Comparative Example) A composite vibrator was manufactured in the same manner as in the first example, except that water was not allowed to pass through the inner pipe of the inner layer pipe in the first example.

The vibrator obtained by this has a flattened cross section,
Moreover, it was curved in the length direction.

(Effects of the Invention) As described above, according to the present invention, a thermoplastic resin pipe has a state in which only the surface of the pipe is in a molten state while the hardness of the inner pipe line of the pipe is maintained, and the thermoplastic resin In the prepreg that is heated together with the pipe, the thermoplastic resin impregnated with reinforcing fibers becomes molten by heating, which prevents the thermoplastic resin vibe from softening and produces a composite pipe in which the pipe and the prepreg are firmly fused. can do.

[Brief explanation of drawings]

1 and 2 show drawings related to the manufacturing method of the present invention, and FIG. 1 is an explanatory diagram illustrating the manufacturing method of a composite pipe,
FIG. 2 is an explanatory diagram illustrating a method for manufacturing a pre-reg. 1... Thermoplastic resin pipe 2... Pre-leg 2a... Reinforced fiber roving (reinforced fiber) 2b...
Thermoplastic resin 3...Cooling medium

Claims (1)

[Scope of Claims] 1) A method of fusing a string-like or tape-like prepreg made of reinforcing fibers impregnated with a thermoplastic resin to the outer periphery of a thermoplastic resin pipe, the method comprising: A method for manufacturing a composite pipe, comprising: passing a cooling medium through the pipe, heating and melting the surface of the pipe and at least the welding surface of the prepreg, and fusing the prepreg to the outer periphery of the thermoplastic resin pipe.