JPS6048340A - Manufacture of hose - Google Patents

Abstract

PURPOSE:To obtain a high-quality hose whose inner tube outer surface is free from roughness, by extruding a melted resin to cover a preheated mandrel, cooling it to mold a hose inner tube, covering the inner tube outer surface with a reinforcing layer, etc., and vulcanizing them integrally. CONSTITUTION:A mandrel has been previously heated in a heating tank or the like to keep the surface at a prescribed temperature. After a melted resin extruded from an extruder is caused to cover the mandrel outer surface, it is cooled to mold a hose inner tube. The inner tube outer surface is covered with a reinforcing layer, a rubber outer tube, etc. in known manner, and finally they are integrally vulcanized to obtain the aimed hose. EFFECT:The productivity can be improved, the thickness of the inner tube becomes uniform, and the flexibility can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in a method for manufacturing a resin-rubber composite hose provided with an outer tube and the like.

Conventional. Various purposes, utilizing the respective properties of resin and rubber.
Resin-rubber composite hoses are used for this purpose.

The method for manufacturing such a hose is as follows. After extruding a resin inner tube using an extruder, a mandle is inserted into the inner tube,
Thereafter, a reinforcing layer is braided on the outer surface of the inner tube, and the outer surface is further covered with a rubber outer tube.

How to vulcanize these together (method person), or.

A method in which melted and plasticized resin is extruded and coated onto a mandle using an extruder, and then cooled to form a hose inner tube (method B).
: The reinforcing layer, rubber outer tube, etc. are the same as method A), etc. are known.

However, this method has the following drawbacks.

Method A requires a lot of effort to insert the mandle into the inner tube, and the surface accuracy of the mandle is difficult. Depending on the dimensional accuracy, wrinkles may occur on the inner surface of the inner tube.

The inner pipe may cave in, adversely affecting hose performance.

On the other hand, in method B, the temperature difference between the molten resin extrusion coated onto the mandle and the mandle surface is large, so the extrusion coated resin is rapidly cooled on the mandle, but the cooling rate is also uneven. Irregularities may be formed on the outer surface of the inner tube. If the inner tube wall thickness becomes uneven, or if the inner tube becomes uneven, distortion may remain throughout the inner tube, which may cause the inner tube to break due to a slight bending load. happens.

The present invention was invented in view of the above circumstances, and provides a method for manufacturing a high-quality resin-rubber composite hose with excellent productivity and solving the problems of the conventional methods (especially method B). The entire purpose is to provide.

The feature of the present invention is that the inner pipe of the hose is formed by heating the mantle in advance and then extrusion coating the mantle with molten resin while keeping the surface at a predetermined temperature.

The present invention will be explained in detail below.

The method of the present invention involves heating the mantle in advance using a heating tank or the like, keeping the surface at a predetermined temperature, extruding and coating the outer surface of the mantle with molten resin extruded from an extruder, and then cooling the mantle. The hose is finally vulcanized to obtain the desired hose.

The mantle used is one made of an elastic member (for example, made of rubber) that can be wound up twice, and the surface temperature due to heating is determined by the resin material (melting point, heat shrinkage rate, etc.).

It is determined appropriately depending on the inner tube wall thickness, mantle material, mantle take-up speed, workability, etc., but it is desirable that the temperature is at least 40°C or higher and below the melting point of the resin at the time of extrusion coating. .

Further, a mold release agent (such as silicone) is usually used on the outer surface of the mantle, and the mold release agent may be applied either before or after heating.

In addition, when cooling after the resin has been extruded and coated on the outer surface, it is recommended to perform air cooling before main cooling (forced cooling) depending on the resin material, inner tube wall thickness, etc. to prevent rapid cooling. Good for keeping the cooling rate uniform and minimizing residual strain generated in the inner tube.

This is preferable for making the wall thickness uniform.

The reinforcing layer is usually constructed as a fiber braided layer, and is fixed to the inner and outer tubes with an adhesive in order to maintain pressure resistance and prevent the braided layer from becoming disordered.

If necessary, an intermediate rubber layer may be provided between the inner tube and the reinforcing layer for the purpose of maintaining the flexibility of the hose.

According to the method of the present invention having the above structure, the inner tube of the hose can be formed by extrusion coating the outer surface of the mantle with resin, so that productivity is improved.

Since the -C molten resin is extruded and coated on the mantle which is heated in advance and its surface maintained at a predetermined temperature, the resin is not rapidly cooled and the residual strain generated in the inner tube can be minimized. No unevenness is formed on the outer surface of the
The wall thickness of the inner tube can also be made uniform.

This has the practical effect of improving the flexibility of the inner pipe (which ultimately results in improved flexibility of the hose).

Next, nine examples of the present invention will be shown.

Hoses were manufactured under the conditions shown in Table 1, and the appearance of the inner tube and the flexibility of the hoses were evaluated. The results are also shown in Table-1.

The reinforcing layer is made of grade braid and is made of 7i124 wood.

The braid angle is 55°, and the final vulcanization conditions are 150°C x 6
A leaded vulcanization of 0 minutes was used.

In addition, to evaluate the flexibility of a hose, fix the horizontal cut surface of one end of a specified length of hose on the board, bend the hose with the other end, and calculate the amount required to bring the horizontal cut surface of the other end into close contact with the board. This was done by measuring a bent cart. The measurements were performed on blank products.

In the table, E P D M l'l ethylene-propylene-
Together with Jien! li: Combined rubber, 08M is chlorosulfonated polyethylene rubber.

As is clear from the results shown in Table 1, according to the method of the present invention, the productivity of hoses such as 1 mI can be improved, and high quality 71 cous with excellent flexibility can be produced.

patent applicant

Claims (1)

[Claims] After extrusion coating the outer surface of the mantle with molten resin extruded from an extruder, it is cooled to form an inner tube of the hose, and at the same time, a reinforcing layer, a rubber outer tube, etc. are provided on the outer surface of the inner tube. , in a method for manufacturing a hose comprising integrally vulcanizing these. 1. A method for manufacturing a hose, which comprises heating a mantle in advance and coating the surface with a molten resin by extrusion while maintaining the surface at a predetermined temperature.