JPH0538764A - Fiber reinforced resin composite tube and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide thin tri-layered structural composite tube, which has enough strength and high production workability. CONSTITUTION:On the outer peripheral surface of tubular core material l. made of thermoplastic resin such as ABS resin or the like, intermediate layer 2, on the outer peripheral surface of which outer layer 3 made of thermoplastic resin such as polyethylene or the like is coveringly formed, is coveringly formed. The intermediate layer 2 is prepared by alternally paralleling a large number of reinforcing fibers 21 made of glass fiber roving and bulky reinforcing fibers 22 such as glass fiber bulky roving or the like to each other and, after that, impregnated with thermosetting resin such as unsaturated polyester resin or the like. The fiber in the intermediate layer is prevented from separating by running resin-impregnated reinforcing fiber bundles to the axial direction of the core material 1 and entwining tire paralleled reinforcing fibers 21 and bulky reinforcing fibers 22 with each other so as to be made into an integral body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced resin composite pipe having a three-layer structure having an intermediate layer made of a fiber-reinforced thermosetting resin and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a fiber-reinforced resin composite pipe, an outer peripheral surface of a tubular core made of a thermoplastic resin is coated with an intermediate layer made of a fiber-reinforced thermosetting resin, and the outer peripheral surface of the intermediate layer is made of a thermoplastic resin. It is known to have a three-layer structure in which an outer layer made of is coated. In this conventional three-layer structure, a large number of uniform reinforcing fibers, in which the intermediate layer is impregnated with a resin, are formed by aligning them in the axial direction of the core material, or the reinforcing fibers are further wound on the reinforcing fibers. Was formed.

[0003]

However, when the intermediate layer is formed by uniformly reinforcing fibers in the axial direction of the core material, for example, compression in the cross-sectional direction is performed by crushing the tube in the central portion of the tube. When a concentrated load is applied, the pipe is deformed to locally concentrate stress, and each reinforcing fiber is separated, so that the pipe is easily broken. In particular, when the thickness of the intermediate layer is thin, the reinforcing fibers are very easily separated, so that there is a problem that it is difficult to obtain a thin tube having sufficient strength.

Further, when the intermediate layer is wound around the reinforcing fibers aligned in the axial direction of the core material, the reinforcing fibers are further wound, but the above problems are solved, but the strength is sufficient. In the manufacturing process, a device for winding a reinforcing fiber and a winding process are required, which causes a problem of reduced workability. It is an object of the present invention to provide a fiber-reinforced resin composite pipe and a method for manufacturing the same, which solves the conventional problems.

[0005]

In order to solve the above problems, in the fiber-reinforced resin composite pipe of the present invention, an outer peripheral surface of a tubular core material made of a thermoplastic resin is coated with an intermediate layer made of a fiber-reinforced thermosetting resin. In the fiber-reinforced resin composite pipe in which the outer peripheral surface of the intermediate layer is covered with an outer layer made of a thermoplastic resin, a large number of reinforcing fibers in which the intermediate layer is impregnated with resin and bulky reinforcing fibers having a higher bulk are alternately cored. It is formed integrally by being aligned in the axial direction of the material and intertwined with each other.

Further, in the method for producing a fiber-reinforced resin composite pipe of the present invention, a thermoplastic resin is extruded to form a tubular core material, and a large number of reinforcing fibers and bulky reinforcing fibers more bulky than these are alternately aligned. After impregnating the core material with the thermosetting resin and coating these reinforcing fibers on the outer peripheral surface of the core material along the axial direction, it is introduced into a drawing mold and a curing furnace to be heat-cured to form an intermediate layer on the outer peripheral surface of the core material. The outer peripheral surface of the intermediate layer is extrusion-coated with a thermoplastic resin to form an outer layer.

[0007]

According to the present invention, in the intermediate layer, a large number of reinforcing fibers and bulky reinforcing fibers which are bulkier than the reinforcing fibers are alternately aligned in the axial direction of the core material. The fibers are entwined with each other and closely adhered to each other to be firmly integrated, and the separation of the reinforcing fibers against the compressive load in the cross-sectional direction can be prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. First, the fiber-reinforced resin composite pipe of the present invention will be described with reference to FIG. In the drawings, reference numeral 1 denotes a tubular core material, which is made of a thermoplastic resin and generally has a circular cross section. The core material 1 is generally made of ABS resin, but may be made of other thermoplastic resin such as polyvinyl chloride, polypropylene and polyethylene. The core material 1 is manufactured by extrusion molding as described later.

Reference numeral 2 is an intermediate layer, which is formed by coating on the outer peripheral surface of the core material 1. The intermediate layer 2 is made of a fiber-reinforced thermosetting resin, and specifically, a large number of resin-impregnated reinforcing fibers 2 are provided.
1 and bulky reinforcing fibers 22 that are bulkier than this are alternately aligned, and these reinforcing fiber bundles are formed so as to be covered along the axial direction of the core material 1. As shown in FIG. 1B, the reinforcing fiber 21 and the bulky reinforcing fiber 22 have two reinforcing fibers 21 between the adjacent bulky reinforcing fibers 22 in the intermediate layer 2.
It is preferable in terms of strength that they are aligned so as to be positioned on the inner and outer surfaces of the. Although the thickness of the intermediate layer 2 varies depending on the diameter of the composite pipe, the thickness of the intermediate pipe 2 is generally 1.5 mm or less so that the whole pipe can be thin.

Reinforcing fiber 21 and bulky reinforcing fiber 22
As the fiber, roving, glass fiber such as yarn, carbon fiber, aramid fiber, or fiber appropriately mixed with these is used. As the bulky reinforcing fiber 22, for example, in the manufacturing process of the roving reinforcing fiber 21, a bulky fiber is used in which high-pressure air is blown onto the fiber to partially disperse each fine fiber into a cotton shape. In the mid layer 2, the cotton-like portion of the bulky reinforcing fiber 22 and the reinforcing fiber 21 are intertwined and joined to each other.

As the thermosetting resin, unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol resin, urethane resin and the like are used. This thermosetting resin includes a curing agent, a photopolymerization initiator, an accelerator,
A pigment or the like may be blended appropriately.

An outer layer 3 is formed on the outer peripheral surface of the intermediate layer 2 by coating. The outer layer 3 is formed of a thermoplastic resin such as polyethylene, polypropylene, polyvinyl chloride, ABS resin. The outer layer 3 is generally formed on the outer peripheral surface of the intermediate layer 2 by extrusion molding.

Next, a method for manufacturing the fiber-reinforced resin composite pipe of the present invention will be described with reference to FIG. First, a thermoplastic resin is extruded into a tubular shape by an extruder 4, introduced into a cooling tank 5, cooled to form a core material 1, and the core material 1 is taken by a take-out machine 6. As the thermoplastic resin, the above-mentioned resins such as ABS resin are used. Generally, the core material 1 is extruded into a tubular shape having a circular cross section.

Next, a large number of reinforcing fibers 21 and bulky reinforcing fibers 22 which are bulkier than the reinforcing fibers 21 are alternately aligned and introduced together with the core 1 into the intermediate layer forming device 7. In the intermediate layer forming device 7, the reinforcing fiber 21 and the bulky reinforcing fiber 22 are impregnated with a thermosetting resin, and the reinforcing fiber bundle is covered along the axial direction of the core material 1 to remove excess resin by squeezing. To do. At this time, the reinforcing fiber 21 is entangled and joined to the cotton-like portion of the bulky reinforcing fiber 22. In addition, two reinforcing fibers 21 are provided between the adjacent bulky reinforcing fibers 22 and are aligned.
It is preferable that the reinforcing fibers 21 are positioned on the inner and outer surfaces of the intermediate layer formed by coating the outer peripheral surface of the core material 1 because a high-strength tube can be obtained.

As the reinforcing fiber 21 and bulky reinforcing fiber 22, the above-mentioned fibers such as glass fiber roving are used. For example, as the reinforcing fiber 21, glass fiber roving (Central Glass # 900), bulky reinforcing fiber 22
For example, glass fiber bulky roving (# 1460 manufactured by Asahi Fiber Glass) or the like is used. As the thermosetting resin, the above-mentioned resins such as unsaturated polyester resin are used, methyl ethyl ketone peroxide is used as a catalyst, and 6% cobalt naphthenate is used as an accelerator.

Next, the core material 1 coated with the intermediate layer is formed.
Is introduced into a plurality of pultrusion molding dies 8 and a curing furnace 9, and is heat-cured. At this time, the reinforcing fiber 21 and the bulky reinforcing fiber 22
And are integrated while being intertwined with each other to form a strong intermediate layer. Next, the core material 1 is introduced into the extruder 10, and the outer peripheral surface of the intermediate layer of the core material 1 is extrusion-coated with the thermoplastic resin. As the thermoplastic resin, the above-mentioned resin such as polyethylene is used. Subsequently, it is cooled by the cooling tank 11, taken by the take-up machine 12, and cut into a predetermined length by the cutting machine 13.

The method for producing the fiber-reinforced resin composite pipe of the present invention is continuously carried out as shown in FIG. 2, but in some cases, it may be produced separately in each step.

[0018]

As described in detail above, in the fiber-reinforced resin composite pipe of the present invention, a large number of reinforcing fibers having an intermediate layer impregnated with resin and bulky reinforcing fibers having a higher bulk are alternately arranged in the axial direction of the core material. Since they are aligned and entwined with each other, the fibers do not separate even when a compressive load in the cross-sectional direction is applied,
The strength can be improved, the intermediate layer can be made thin, and the whole tube can be made thin to provide a strong composite tube.

Further, in the method for producing a fiber-reinforced resin composite pipe of the present invention, a large number of reinforcing fibers and bulky reinforcing fibers which are bulkier than the reinforcing fibers are alternately aligned and impregnated with a thermosetting resin, and these reinforcing fibers are used as a core material. Since the outer peripheral surface is coated along the axial direction, the workability can be improved without the need for a reinforcing fiber winding device or a winding process as in the conventional case in order to increase the strength of the pipe.

[Brief description of drawings]

FIG. 1 shows an embodiment of the fiber-reinforced resin composite pipe of the present invention,
(A) is an overall sectional view, and (B) is an enlarged sectional view of a main part.

FIG. 2 is a process explanatory view showing a method for producing a fiber-reinforced resin composite pipe of the present invention.

[Explanation of symbols]

 1 core material 2 middle layer 21 reinforcing fiber 22 bulky reinforcing fiber 3 outer layer

Claims (2)

[Claims] 1. An outer peripheral surface of a tubular core material made of a thermoplastic resin is coated with an intermediate layer made of a fiber-reinforced thermosetting resin,
In a fiber-reinforced resin composite pipe in which the outer peripheral surface of the intermediate layer is covered with an outer layer made of a thermoplastic resin, a large number of reinforcing fibers in which the intermediate layer is resin-impregnated and bulky reinforcing fibers of a bulkier are alternately formed as core materials. A fiber-reinforced resin composite pipe that is axially aligned and entwined with each other to be integrally formed. 2. A thermoplastic resin is extruded to form a tubular core material, and a large number of reinforcing fibers and bulky reinforcing fibers having a higher bulk are alternately aligned and impregnated with a thermosetting resin. After coating the outer peripheral surface of the core along the axial direction,
A method for producing a fiber-reinforced resin composite pipe in which a pultrusion molding die is introduced into a curing furnace and heat-cured to form an intermediate layer on the outer peripheral surface of the core material, and the outer peripheral surface of the intermediate layer is extrusion coated with a thermoplastic resin to form an outer layer ..