JPS58160124A - Manufacture of laminated pipe - Google Patents

Abstract

PURPOSE:To obtain the laminated pipe having high quality easily at low cost without a special device by a method wherein a prepreg sheet is wound on a wound core consisting of a material, a thermal expansion coefficient thereof is large and mold release property thereof is excellent, and heated and cured while the wound core is thermally expanded, cooled and extracted. CONSTITUTION:The prepreg sheet 21 manufactured by impregnating a thermocuring synthetic resin (such as epoxy resin) composition into a sheet-shaped material and bringing the material to a semi-rigid state is wound on the wound core 1 consisting of the material (such as polypropylene), the thermal expansion coefficient thereof is large and mold release property thereof is excellent, and heated in a drying furnace. Accordingly, the viscosity of the synthetic resin composition is lowered while the wound core 1 is thermally expanded, and an inside diameter of the prepreg sheet 21 wound is expanded. The prepreg sheet 21 is cured under the state to form the laminated pipe 2, and cooled to generate a clearance 4 between the pipe and the outer circumferential surface of the wound core 1, which is extracted, and the desired laminated pipe 2 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laminated tube, which comprises winding a prepreg sheet around a core, heating and curing it, and then removing the core.

Generally, laminated pipes are manufactured by the method described below. That is, first, a release paper is wrapped several times around a metal cylindrical core having an outer diameter corresponding to the inner diameter of the laminated tube, and then a synthetic resin composition such as epoxy resin is wrapped around a cylindrical core made of metal, and then a synthetic resin composition such as epoxy resin is wrapped around a cylindrical core made of metal, and then a synthetic resin composition such as epoxy resin is wrapped around a paper, polyethylene terephthalate, or aromatic polyamide paper. A prepreg sheet that has been pre-impregnated into a sheet-like material such as glass cloth, carbon cloth, etc. and then brought into a semi-cured state is wound until it corresponds to the desired outer diameter of the laminated tube, and then heated and cured.

Since the viscosity of the impregnated synthetic resin composition such as epoxy resin in the wound prepreg sheet is reduced by heating, the prepreg sheet can be integrated after curing to obtain a laminated tube. The cured laminated tube is then extracted from the metal cylindrical core using a hydraulic press to complete the manufacturing process.

However, according to the conventional manufacturing method, which is expensive, a tube extracting device using a hydraulic press is required to extract the laminated tube from the cylindrical core, and am paper is wrapped several times on the cylindrical core to improve slippage. You need to keep it good. Furthermore, there are many drawbacks, such as the fact that scraps of release paper adhere to the outer circumferential surface of the cylindrical core and the inner surface of the laminated tube after being pulled out, which requires work to remove them.

The present invention has been developed in view of the conventional problems such as cost increase, and can be easily carried out without the use of tube extraction equipment, thus producing a low cost and high quality laminated tube. The purpose is to provide a method for

That is, in the present invention, a prepreg sheet is directly wound around a cylindrical core made of a material with a large coefficient of thermal expansion and good mold releasability, and then heated in a drying oven to thermally expand the cylindrical core. It is characterized by hardening the laminated body with the inner diameter expanded, and then slowly cooling it to shrink the cylindrical core to create a gap between the laminated tube and the laminated tube, and then pull out the laminated tube from the cylindrical core. That is.

Next, an embodiment of the manufacturing method of the present invention will be described with reference to the drawings.

Figures (&) to (e) are schematic vertical cross-sectional views of articles at each step in an embodiment of the method for manufacturing a laminated pipe of the present invention.

In the figure, (1) is a winding core with a large coefficient of thermal expansion and good releasability, such as plastic (such as tGf
A cylindrical body made of polypropylene, Teflon, nylon, acetal resin, etc.) is used. A sheet material (for example, paper, polyethylene terephthalate, aromatic polyamide paper, glass cloth,
(carbon cloth, etc.) is impregnated with a synthetic resin composition (e.g., epoxy resin, etc.) and semi-cured prepregsy) $◇ is wound several times (steps (a) → (b)
) ). Next, this is heated in a drying oven. The synthetic resin composition, which was in a semi-cured state at room temperature, is heated to reduce its viscosity, while the heated cylindrical core expands and expands the inner diameter of the wound prepreg sheet 〇, increasing its density. A force to increase the height acts, resulting in a high-density laminated pipe (2) (step (b) → (0)). When slow cooling is started from the point at which curing is completed, the winding core (1) starts to shrink, but no significant shrinkage occurs in the laminated layer w (2) consisting of the cured prepreg sheets (step (0) )→(d)).

Therefore, there is a gap (s) between the winding core (1) and the laminated tube (2).
) occurs, and the winding core can be easily extracted from the 911M pipe (2) (step (gradient→(·)).

Since the present invention is constructed in a cost effective manner, it has the following effects.

(1) For example, a tube extraction device such as a hydraulic press is used by creating a gap between the inner surface of the laminated tube and the outer peripheral surface of the plastic core by utilizing the property of thermal expansion of the core made of plastic. The extraction work can be easily carried out without any problems.

(■) By eliminating the need for a extraction device, the manufacturing time for laminated pipes can be greatly shortened, and therefore manufacturing costs can be reduced.

(fli) By using a material with good release properties (for example, plastic) for the core, there is no need to wind the release paper, and there is no need to clean the release paper waste, so the working time can be shortened.

(iv) After winding the prepreg sheet, the winding core is removed when heated! #
By swelling and increasing the density of the prepreg sheet (vIII layer tube), a high quality laminated tube with fewer voids can be obtained.

Note that the shape of the winding core is not particularly limited, and may be used in accordance with the desired laminated pipe, such as a pipe-like shape, a hollow rod-like shape, or a rectangular shape.

[Brief explanation of the drawing]

Figures (a) to (•) are schematic vertical cross-sectional views of articles at each step in an embodiment of the method for manufacturing a laminated pipe of the present invention. (Drawing code) (1) Two-volume core (2): 11-layer tube (8) Nibbly preg sheet (4): Agent between A Shin Kuzuno - (1 other person) 5. Subject of amendment (1) Column “Detailed Description of the Invention” in the specification (2) Drawing 6, contents of amendment (1) “Prepreg sheet” in line 6 on page 116 of the specification “a”
It is corrected as "between llI". (2) Correct page 6, line 7 ♀ “(4): @ between” to [Niburi Preg Sheet]. (8) Amend the drawing as shown in the attached sheet. that's all

Claims (1)

[Claims] (1) After winding the prepreg sheet around a core made of a material with a large coefficient of thermal expansion and good yIIAiIA properties,
At the same time as heating and drying, the winding core is thermally expanded to expand the inner diameter of the wound prepreg sheet, which is then cooled to create a gap between the winding core and the outer peripheral surface of the winding core. A method of manufacturing laminated pipes characterized by removing the core.