JPH0468029A - Hollow pipe - Google Patents

Abstract

PURPOSE:To obtain a hollow pipe of excellent mechanical properties inexpensively in good productivity by a simple molding process, by forming a hollow pipe from a thermoplastic resin containing fibrous reinforcements arranged so that specified conditions may be satisfied, and making the surface of the pipe smooth. CONSTITUTION:A hollow pipe is formed from a thermoplastic resin (e.g. poly-eth ylene terephthalate) containing fibrous reinforcements (e.g. glass fibers) randomly arranged in parallel to the direction of the axis of the pipe along its surface, and the surface of the pipe is made smooth.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hollow tube material made of a thermoplastic resin containing fiber reinforcement, which has excellent mechanical properties and is inexpensive.

[Prior art and problems to be solved by the invention] In recent years, research has been carried out on adding inorganic fillers such as calcium carbonate, asbestos, glass fiber, mica, and talc to synthetic resins to impart mechanical strength and heat resistance. It is being done in all areas. These hollow tubes made of synthetic resin containing inorganic fillers are usually formed by a method using a mandrel. Examples include the prepreg wrap molding method, in which a prepreg sheet is wound around a mandrel, the outside of the sheet is wrapped with heat shrink tape, and then thermoformed, and the filament winding method, in which reinforcing fibers impregnated with resin is directly rolled onto a mandrel and molded. It is. Among these forming methods, compared to the prepreg wrap forming method, the filament winding method involves applying tension to the fibers and winding them around a mandrel to form them, so defects such as sagging and meandering of the fibers are less likely to occur, and fiber strength and It has the advantage that a hollow tube material with excellent mechanical properties can be obtained by utilizing the elastic modulus.

However, the prepreg wrap molding method involves a process of making prepreg, a process of winding the prepreg around a mandrel,
The filament winding method is an extremely complicated process that involves winding a heat-shrinkable tape, thermoforming, etc., and the filament winding method involves winding resin-impregnated fibers around a mandrel, curing the resin, etc. Therefore, there is a problem that the molding cost of the obtained hollow tube 1 becomes significantly high.

Therefore, in view of the above-mentioned current situation, the present inventors investigated a hollow tube material that can be obtained without the above-mentioned complicated process and has the same performance as conventional hollow tube materials, and as a result, they arrived at the present invention. It is something.

[Means for Solving the Problems] The present invention provides a hollow tube material made of a thermoplastic resin containing a fibrous reinforcing material, in which the fibrous reinforcing material is parallel to the surface of the tubular material and extends in the axial direction of the tubular material. It is a hollow tube material characterized by being randomly arranged.

The fibrous reinforcing material used in the present invention is glass fiber,
It is obtained from fibrous substances such as carbon fibers, metal fibers, fibers made of organic compounds such as polyvinyl alcohol and polyarylate, and ceramic fibers, and these can be used alone or in combination of two or more. Particularly in the present invention, it is preferable to use glass fiber from the viewpoint of economy. The length of the fiber used is 10 mm or more, especially 2
The fiber diameter is preferably 0 mm or more, and the fiber diameter is 2 to 30 μ, especially 10
Fibers in the range of ~25μ are preferred. The surface of the fibers is preferably treated with a treatment agent such as a silane coupling agent that provides adhesive properties suitable for thermoplastic resins. The shape of the fibrous reinforcing material may be any shape as long as it is parallel to the surface of the hollow tube material from which the fibers are obtained and arranged randomly in the axial direction, such as chopped strand mats, swirl mats, binders, etc. Examples of mats include mats in which the fibers are fixed in place, or mats in which the fibers are entangled to a certain degree by needling. Moreover, these mats can also be used in combination.

In the hollow tube material of the present invention, the fibrous reinforcing material is 10% by weight.
In particular, the content is preferably 20% by weight or more. If the content of the reinforcing material is less than 10% by weight, it is not preferable because satisfactory mechanical properties of the resulting hollow tube material cannot be obtained.

The fibrous reinforcing material of the present invention may further include glass beads, glass micro balloons, granular fillers such as calcium carbonate, mica, etc., as long as they do not damage the fiber orientation.
Flake-like fillers such as glass flakes, talc, and sericite, and needle-like fillers such as wollastonite can be used alone or in combination of two or more.

Examples of thermoplastic resins used in the present invention include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyester elastomers, polyamide resins such as nylon 6, nylon 66, and nylon 12, polyolefin resins such as polypropylene, polymethylpentene, and polyethylene, and polysulfone. , aromatic polyolefin resins such as polyallylsulfone and polyethersulfone, polyacetal resins, polycarbonate resins, modified polyphenylene oxide resins, polyetherimide resins, polyetheretherketone resins, A
Examples include BS resin, but the resin is not limited to these resins and can be appropriately selected depending on the purpose of use. These resins can be used alone, modified, or blended, and additives such as antioxidants, ultraviolet absorbers, copper inhibitors, flame retardants, colorants, and internal mold release agents are added to impart properties. , a lubricant, an antistatic agent, etc. may be added.

The form in which the thermoplastic resin is used is preferably in the form of a notebook, or may be used in a form that facilitates impregnation with the reinforcing material, and is not limited to the form.

The hollow tube material in the present invention can be manufactured, for example, as follows. First, a predetermined amount of fibrous reinforcing material and sheets of thermoplastic resin are alternately stacked and supplied to a device having a pair of upper and lower belts, and the reinforcing material is heated and pressurized to a temperature higher than the softening point or melting point of the resin. A sort for molding is obtained by integrating and cooling the thermoplastic resin. Next, the obtained sheet is molded into a hollow tube material using ordinary fiber-reinforced plastic, such as a method in which a molding sort is wound around a mandrel and pressure molded in a mold (
Japanese Patent Publication No. 60-15460), a method of pressing against the inner surface of a retractable mold by inflating a bag-like inflatable body placed between layers of a molding sheet (Japanese Patent Publication No. 2-7293)
(see Publication No. 5), etc., to form a hollow tube material.

[Function] The hollow tube material according to the present invention has a simple molding process, and
Since the fibrous reinforcements are parallel to the surface of the hollow tube and randomly arranged in the axial direction of the tube, the tube has excellent mechanical properties. Moreover, the hollow tube material according to the present invention is lighter in weight than hollow tube materials obtained by prepreg wrapping method, filament winding method, etc.
It's cheap. The hollow tube material according to the present invention has high productivity, is lightweight, and has excellent mechanical properties, so it can be used for various purposes ranging from small diameter hollow tubes used in sports leisure fields such as golf clubs, fishing rods, and badminton shafts. It can be used as a large-diameter hollow pipe used for sewage, agricultural water, industrial water, etc., which easily takes the form of fibers.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 A chopped strand mat made of glass fiber with a length of 50 mm (basis weight 300 g/m', manufactured by Central Brass Fiber Co., Ltd.) and a notebook made of polyethylene terephthalate resin with a thickness of 0.25 mm were sequentially laminated, and the weight After adjusting the resin to 60% by weight, 290~
It was heated to 300°C and impregnated under pressure at a pressure of 10 kg/cm2. A plurality of sheets of the obtained sort for molding are laminated and a bag-like expansion body made of synthetic rubber is interposed between them, and 16
The sheet is heated to 0°C and put into a mold, and then the mold is closed and air is supplied to the inside of the bag-shaped expanding body to pressurize the molten molding sheet from the inside and expand it. The molding sheet pressed against the mold wall has an inner diameter of 25 mm and a wall thickness of 4II.
A hollow tube having a length of 1 m was obtained.

A test piece was cut from the obtained hollow tube material, and when the cross section was visually observed, the glass fibers were parallel to the surface of the hollow tube material and randomly arranged in the axial direction. Moreover, when observed with the naked eye, no voids were observed. In addition, the test piece was tested at a span of 200 in accordance with JIS K6911.
When the bending strength was measured using a 3-point support method in mm, it was 14k.
g/mm'.

Comparative Example I A steel pipe having the same shape and similar bending strength as Example 1 was about three times as heavy as the hollow tube material obtained in Example I in weight.

Comparative Example 2 A sheet for acid form was obtained in the same manner as in Example 1, except that a double punched mat made of glass fiber having a length of 50 nm+m was used instead of the chopped strand mat, and then a hollow tube material was obtained. The springback of the needle punching mat during hollow tube forming is large and the acid forming property is poor. Visual inspection of the cross section of the hollow tube material obtained revealed that there were many voids, and although the glass fibers were arranged randomly in the axial direction of the hollow tube material, they were not arranged parallel to the surface.

[Effects of the Invention] As explained above, the hollow tube material of the present invention has a simple molding process, has excellent mechanical properties because the fibrous reinforcing material has a specific arrangement structure, and is lightweight. be. Furthermore, the molding process is simple and the productivity is high, and it can be used as hollow tubes of any diameter.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the hollow tube material of the present invention, FIG. 2 is a sectional view taken along line A-A of the hollow tube material in FIG. 1, and FIG.
The figure is an enlarged view of the main part of the surface of the hollow tube material of the present invention. 1. Fibrous reinforcing material 2. Thermoplastic resin patent applicant Rira Shi Co., Ltd.

Claims (1)

[Claims] In a hollow tube made of a thermoplastic resin containing fibrous reinforcing materials, the fibrous reinforcing materials are arranged parallel to the surface of the tube and randomly in the axial direction of the tube, and the surface of the tube is A hollow tube material characterized by its smoothness.