JPH04201324A - Manufacture of molded hose - Google Patents

Abstract

PURPOSE:To obtain a bent molded hose whose rigidity is caused to improve without generating creases on a resin layer of the innermost layer, by a method wherein a bent mandrel is inserted into a product of a molded hose main body or that in a semi-vulcanized state under a state where creases are not generated on the resin layer under a bent state and shaping is performed while heating the same at a vulcanization temperature or higher for a fixed time. CONSTITUTION:After forming in order of an inside layer 3, intermediate rubber layer 4, reinforcement yarn layer 5 on an outer circumferential surface of a resin mandrel 2, to which outside rubber layer 6 is applied and vulcanization molding is performed, through which a molded hose main body 1, the inner most layer of which is provided with an inside resin layer 3 is manufactured. In the case where a mold hose main body 1 is molded by bending into a fixed form, a bent mandrel 7 is inserted into a product of a molded hose main body 1 or that in a semi-vulcanized state under a state where especially the intermediate rubber layer 4 is completed its vulcanization or in the semi-vulcanized state and creases are not generated on an inside resin layer 3 under a bent state. Then the hose main body 1 bent into a fixed form is immersed into molten salt at 140-240 deg.C, heated for about 3-60min., the bent mandrel 7 is pulled off from the hose main body 1 after cooling of the hose main body 1. With this construction, a hose where the inside of the resin layer 3 is free from creases is manufactured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a bend-molded hose having a resin layer as the innermost layer, and more specifically, it relates to a method for manufacturing a bend-molded hose having a resin layer as the innermost layer. The present invention relates to a method for manufacturing a molded hose that can produce a well-curved molded hose.

[Prior art]

Conventionally, the structure of a molded hose with a resin layer as the innermost layer used for air conditioning piping of automobiles, etc. includes an intermediate rubber layer and a reinforcing thread layer on the outer peripheral surface of the resin layer.

It is made of a resin and rubber composite material with successive outer rubber layers.

[Problem to be solved by the invention]

However, if a hose made of a composite material of resin and rubber with a resin layer on the innermost layer as described above is bent into a predetermined shape in an unvulcanized state during molding, wrinkles will occur in the bent inner resin layer. However, especially if there is a gap between the inner diameter of the unvulcanized raw pipe and the outer diameter of the bent mandrel, wrinkles may occur on the bent inner surface of the resin layer due to compression due to bending and contraction of the hose body during vulcanization. There was a problem.

In addition, for hoses with a bent mandrel inserted into an unvulcanized tube with a resin layer on the innermost layer, the inner diameter of the hose is 4cm to 25m.
+, there was a problem in that the inner resin layer that was bent at a bending radius of about 150 W or less was wrinkled significantly.

If there are wrinkles in a part of the resin layer as described above, 1, there is a problem in that internal stress concentrates in the wrinkled area, which not only reduces the durability of the molded hose but also leads to a decline in quality. Ta.

[Purpose of the invention]

This invention was devised by focusing on such conventional problems, and provides a vulcanized or semi-vulcanized hose body made of a composite material of resin and rubber with a resin layer in the innermost layer. The purpose of this invention is to provide a method for manufacturing a bend-formed hose that does not cause wrinkles in the innermost resin layer even when bent and formed, has high quality accuracy, and has improved durability. .

[Means to solve the problem]

In order to achieve the above object, the present invention inserts a bending mandrel pre-shaped into a predetermined shape into a molded hose body product or a semi-vulcanized product in a state in which wrinkles do not occur in the resin layer when bent. The gist of this method is to mold the hose body bent into a predetermined shape while heating it above the vulcanization temperature for a predetermined time, and after cooling, pull out the bending mandrel from the hose body to produce a bent hose body with a predetermined shape. It is something to do.

Further, the molding of the hose body is carried out using molten salt at a temperature and time of 140°C to 240°C for 3 minutes to 60 minutes.

[Action of the invention]

This invention is configured as described above, and wrinkles do not occur in the resin layer of the molded hose body product or the semi-vulcanized product, especially when the intermediate rubber layer is already vulcanized or bent in the semi-vulcanized state. In this state, a shaped bent mandrel is inserted, and the hose body bent into the specified shape is heated at 140°C in molten salt.
By immersing the hose at ~240°C, heating it for about 3 minutes to 60 minutes, and removing the bent mandrel from the hose body after the hose body has cooled, a hose without wrinkles in the innermost resin layer can be manufactured. be.

[Embodiments of the invention] The present invention will be described in detail below based on the accompanying drawings.

FIG. 1 shows a partially cutaway perspective view of a molded hose body l embodying the present invention. On the outer peripheral surface of the mandrel 2, an inner resin layer 3, an intermediate rubber layer 4. It is constructed by sequentially applying reinforcing yarn layers or reinforcing wire layers 5 made of spirals, braids, knits, etc., and covering the outer surface with an outer rubber layer 6.

The reinforcing thread constituting the reinforcing thread layer 5 is made of polyester, vinylon, rayon, aramid, etc., and has a dry heat shrinkage rate of 0 to 2.0x, preferably 0 to 1.5% at 150°C for 130 minutes. I'm using the following: In addition to this, reinforcing wire is also used.

Further, as the material of the intermediate rubber layer 4, for example, 11R, C
IIR, CM, C5M, NBR, CR, EPDM, acrylic, etc. are used, and as the outer rubber layer 6, for example, 11R, CIIR, CI'l, C5M, NBR, CR,
EPDM, SBR, etc. are used.

A method for manufacturing such a molded hose body 1 is to simultaneously or simultaneously apply a hollow or solid reusable resin mandrel 2 made of polymethyl pentene resin, etc., and an inner resin layer 3 that will become an inner tube on its outer peripheral surface. Extrude continuously.

Then, an intermediate rubber layer 4 of a predetermined thickness is extruded on the outer peripheral surface of this inner resin layer 3, and further, on the outer peripheral surface of the intermediate rubber layer 4,
blade or spiral.

After forming a reinforcing thread layer 5 consisting of W), an outer rubber layer 6 is sequentially applied and vulcanization molding is performed to produce a molded hose body 1 having an inner resin layer 3 as the innermost layer. .

When such a molded hose body 1 is bent and molded into a predetermined shape, it is necessary to make sure that the intermediate rubber layer 4 is already vulcanized or semi-vulcanized. A shaped bent mandrel 7 as shown in FIG. 2 is inserted in a state in which wrinkles do not occur in the inner resin layer 3 in the bent state. Then, the hose body 1 bent into a predetermined shape is immersed in molten salt at 140'C to 240°C,
By heating for about 3 minutes to 60 minutes and removing the bent mandrel 7 from the hose body 1 after the hose body 1 has cooled, a hose without wrinkles on the inner surface of the resin layer 3 as shown in FIG. 3 can be manufactured. It is something.

The degree of vulcanization of the intermediate rubber layer 4 is preferably 50 to 100 °C, and if the temperature of the molten salt is below 140 °C, molding takes time and productivity cannot be improved; In the case of ``C or more, the physical properties of the resin layer 3 will change, so the above range is preferable. Since the bend-formed hose main body in a predetermined shape is manufactured by the method described above, the final It is possible to manufacture a bend-molded hose with high quality accuracy and improved durability without causing wrinkles in the inner surface resin layer 3.

[Effects of the Invention] As described above, the present invention provides a molded hose body product or a product in a semi-vulcanized state, especially when the intermediate rubber layer is already vulcanized or the inner resin layer is bent in the semi-vulcanized state. A molded bent mandrel is inserted in a state where wrinkles do not occur, and molded while heating at a temperature above the vulcanization temperature for a predetermined period of time to produce a bent hose body in a predetermined shape, resulting in the following excellent effects. It is something.

(a) Since the product or semi-vulcanized raw tube with a vulcanization degree of 50r or higher is bent and molded at a temperature higher than the vulcanization temperature, wrinkles do not occur on the inner resin layer and problems such as stress concentration can be prevented. Therefore, the durability and quality accuracy of the hose can be significantly improved.

(b) Embossing does not require pressure for heating, which reduces deterioration of the yarn in the blinking part.

(C) Since no waste is produced at the end portion during molding, workability is good and material costs can be reduced.

(d) Vulcanization processing is efficient because it can be performed in large quantities at once, and productivity can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a molded hose main body according to the present invention, and FIGS. 2 and 3 are explanatory views showing the manufacturing process of the molded hose. 1... Molded hose body, 2... Resin mandrel, 3
... Inner surface resin layer, 4 ... Intermediate rubber layer, Reinforcement thread layer or reinforcing wire layer, 6 ... Outer surface rubber layer, 7 ...
- Bent mandrel. Agent Patent Attorney Nobuo Ogawa −

Claims (1)

[Claims] 1. Molding in which an inner resin layer is extruded onto a resin mandrel, and an intermediate rubber layer, a reinforcing thread layer or a reinforcing wire layer, and an outer rubber layer are sequentially applied to the outer peripheral surface of this resin layer and then vulcanized. In the method for manufacturing a hose, a bending mandrel pre-shaped into a predetermined shape is inserted into the molded hose body product or a semi-vulcanized product in a state where wrinkles do not occur in the resin layer when bent. A molded hose characterized in that a hose body bent into a shape is molded while being heated above a vulcanization temperature for a predetermined time, and after cooling, a bending mandrel is pulled out from the hose body to produce a bent hose body in a predetermined shape. manufacturing method. 2. The method for manufacturing a molded hose according to claim 1, wherein the molding temperature and time of the hose body are molten salt at 140°C to 240°C for 3 minutes to 60 minutes.