JPS606229B2 - Method for manufacturing rubber hose with fiber braid reinforcement layer - Google Patents

Description

[Detailed description of the invention] This invention has good internal dimensional accuracy, high interlayer adhesion,
The present invention relates to a method for inexpensively manufacturing a rubber hose having a smooth outer surface and a fiber braid reinforcing layer.

Conventionally, as a manufacturing method for a rubber hose having a blade reinforcing layer with good inner diameter dimensional accuracy, an extruded inner rubber layer is semi-vulcanized in advance, and then a reinforcing layer is directly placed in stripes on the outer surface of the inner rubber layer, or a reinforcing layer is directly attached to the outer surface of the inner rubber layer. After interposing an unvulcanized intermediate rubber layer to improve the adhesion between the reinforcing layer and the reinforcing layer, the reinforcing layer is bonded, and the outer surface is covered with an outer rubber layer, and immediately after that, steam vulcanization is performed. Vulcanization of rubber hoses is practiced.

However, in the former method, the adhesion between the layers, especially between the inner rubber layer and the reinforcing layer, is low, and in the latter method, the adhesiveness between the layers is low, and in the latter method, the adhesiveness between the layers is low, and in the latter method, the adhesiveness between the layers is low, and the adhesiveness between the layers is low. Although adhesion is improved, since there is an unvulcanized intermediate rubber layer, the stitches of the braid reinforcement layer are affected by both the shrinkage of the fiber reinforcement layer and the expansion of the rubber of the intermediate rubber layer when the rubber hose is heated and vulcanized. A part of the intermediate rubber layer swells, and this appears as irregularities on the surface of the outer rubber layer, which has the disadvantage of lowering the commercial value of the rubber hose.

For this reason, a lead coating process is purposely included in the rubber hose manufacturing process to coat the outer surface of the rubber hose with lead to prevent unevenness from appearing on the surface of the outer rubber layer, which increases the manufacturing cost of the rubber hose. There were some drawbacks.

This invention was invented in view of the above points, and in order to eliminate the above drawbacks, an extrusion molded inner rubber layer is attached to an unvulcanized intermediate layer on the outer surface of a semi-vulcanized inner rubber layer. The plaid reinforcing layer of fibers is green-laced with a rubber layer interposed, and then the hose is heated to a rubber hose vulcanization temperature (150°C to 1.5°C).
Preheat at a temperature close to 6 pi○ to almost complete the shrinkage of the fibers in the blade reinforcing layer and the fluidity of the rubber in the intermediate rubber layer, then cover the outer surface with the outer rubber layer, and perform the main heat vulcanization. manufactured a rubber hose having a fiber braid reinforcement layer.

The preheating time to complete the shrinkage of the fibers in the blade reinforcing layer and the flow of the rubber in the inner rubber layer depends on the thickness of the intermediate rubber layer or the density of the blade reinforcing layer, but at the above temperature, it is about 10 to 19 minutes. When the intermediate rubber layer and the blade reinforcing layer are heated and vulcanized in steam, the fibers of the blade reinforcing layer contract, strongly tightening the semi-vulcanized inner rubber layer and the outer surface of the uncured intermediate rubber layer. On the other hand, since the inner rubber layer is semi-vulcanized, it will not flow due to this heating, but the unvulcanized intermediate rubber layer will flow and expand due to this heating.
Since a mandrel or a fluid for regulating the inner diameter is sealed in the inner rubber layer, a hose is obtained in which a portion of the intermediate rubber layer ejects from the stitches of the braid reinforcing layer in the form of a large number of convexities.

Therefore, if the outer surface of the hose where a part of the intermediate rubber layer is ejected in a convex shape from the stitches of the braid reinforcing layer is coated with the outer rubber layer using, for example, a crosshead extruder, the outer rubber layer will form the stitches of the braid reinforcing layer. It is possible to cover the outer surface of the plaid reinforcing layer with an outer surface rubber layer that fills the protruding spaces between the protrusions and has no irregularities.

Even if the hose obtained by the above method is heated by main heating of the rubber hose (150 qo x 3 minutes to 150 qo x 50 minutes), the rubber flow in the inner rubber layer and the intermediate rubber layer and the blade reinforcing layer will not change. There is almost no shrinkage of the fibers, and the disadvantage of causing unevenness on the outer rubber layer due to the protrusions of the intermediate rubber layer ejected from the stitches of the blade reinforcing layer can be solved.

In addition, since the inner rubber layer and the blade reinforcing layer are preheated and vulcanized with an intermediate rubber layer interposed between them, and then main vulcanization is performed, the adhesion between the inner rubber layer and the blade reinforcing layer is not impaired at all. Part of the intermediate rubber layer is made to protrude as convexities on the outer surface of the blade reinforcing layer by preheating and vulcanization, and then the outer surface rubber layer is coated on the outer surface, filling in the gaps between the convexities, so that the intermediate layer is not the same as the outer rubber layer. The rubber hose adheres with the technique drawing effect, resulting in a rubber hose with high interlayer adhesion. Furthermore, since there is no need to worry about creating irregularities on the outer rubber layer during the main heat vulcanization, there is no need to take the trouble of setting up a lead process, so there is no need to worry about lead pollution, and a rubber hose with a fiber braid reinforcing layer can be manufactured at low cost. You can.

Furthermore, since the inner rubber layer is semi-vulcanized in advance, the inner diameter dimension is less likely to change, making it possible to provide a rubber hose with good inner dimensional accuracy.

Claims (1)

[Claims] 1 A step of semi-vulcanizing the extruded inner rubber layer, a step of interposing an unvulcanized intermediate rubber layer on the outer surface of the semi-vulcanized inner rubber layer and braiding a fiber braid reinforcing layer, and forming the hose into a rubber hose. a preliminary heat dissipation vulcanization step in which the shrinkage of the fibers and the fluidization of the rubber in the intermediate rubber layer are substantially completed by heating to a temperature close to the vulcanization temperature;
1. A method for manufacturing a rubber hose having a fiber braid reinforcing layer, comprising the steps of coating with an outer rubber layer and then performing main heat vulcanization.