JPS606228B2 - Method for manufacturing rubber hose with fiber braid reinforcement layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing at low cost a rubber hose having a fiber braid reinforcing layer with high interlayer adhesion and a smooth outer surface.

Conventionally, a method for producing a rubber hose having a braided reinforcing layer of fibers involves braiding a braided reinforcing layer of fibers on the outer surface of an unvulcanized inner rubber layer, covering the cover with a rubber layer, and then directly steam-vulcanizing the rubber hose. Vulcanization is performed.

However, when a rubber hose is manufactured by the above method, a part of the inner rubber layer bulges out from the stitches of the braid reinforcement layer due to both the shrinkage of the threads of the fiber braid reinforcement layer and the expansion of the rubber during heating and vulcanization of the rubber hose, and this causes the outer rubber layer to bulge out from the stitches of the braid reinforcement layer. This has the disadvantage that unevenness appears on the surface of the rubber layer, reducing the commercial value of the rubber hose.

For this reason, in the past, a lead process was added to the rubber hose manufacturing process to cover the outer surface of the rubber hose with lead to prevent unevenness from appearing on the surface of the outer rubber layer, resulting in high manufacturing costs for rubber hoses. There were some drawbacks. In addition, as a manufacturing method for rubber hoses that prevents a part of the inner rubber layer from bulging out from the stitches of the braid reinforcing layer, the inner rubber layer is semi-vulcanized in advance, so that the braid can be reinforced when the rubber hose is cured. A method of manufacturing a rubber hose is also known in which a portion of the inner rubber does not bulge out through the stitches of the braid reinforcing layer even if the layer shrinks and becomes combed into the inner rubber layer. In this method of manufacturing rubber hoses, a part of the inner rubber layer does not bulge out from the stitches of the braided reinforcing layer, and there is no unevenness on the surface of the outer rubber layer. Can be manufactured cheaply.

However, on the other hand, since the inner rubber layer is semi-hardened, interlayer adhesion between the inner rubber layer and the plaid reinforcing layer is poor, and adhesives with good adhesion properties cannot be found, and even if they are available, they are expensive. There were drawbacks. This invention was invented in view of the above points, and in order to eliminate the above drawbacks, after a fiber plaid reinforcing layer is brazed on the outer surface of the inner rubber layer of an unfinished bowl. The rubber hose heating temperature (150
After preheating at a temperature close to ~160 qo) to complete the shrinkage of the fibers of the blade reinforcement layer and the flow of the inner rubber layer,
A rubber hose having a fiber braid reinforcing layer was manufactured by coating the outer surface with an outer rubber layer and subjecting it to heat vulcanization.

The preheating time to complete the shrinkage of the fibers in the blade reinforcing layer and the fluidization of the rubber in the inner rubber layer depends on the thickness of the inner rubber layer or the density of the blade reinforcing layer, but at the above temperature it takes about 10 to 10 minutes. When the inner rubber layer and the blade reinforcing layer are heated and vulcanized in steam for 15 minutes, the fibers of the blade reinforcing layer contract and tightly tighten the outer surface of the inner rubber layer, while the inner rubber layer also undergoes initial flow, causing the inner rubber layer to shrink. Since a mandrel or a fluid is sealed inside to regulate the inner diameter, a hose is obtained in which a portion of the inner rubber is ejected from the stitches of the braid reinforcing layer in the form of many protrusions.

Therefore, if the outer surface of the hose where a part of the inner 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 become a braid reinforcing layer. It is possible to cover the outer surface of the blade reinforcing layer with an outer surface rubber layer which fills up the protrusions protruding from between the stitches and has no unevenness on the outer surface of the blade reinforcing layer.

Even when the hose obtained by the above method is heated by main heating of the rubber hose (150°C x 30 minutes to 150°C x 50 minutes), the rubber in the inner rubber layer does not flow and the fibers in the blade reinforcing layer shrink. This eliminates the drawback that the protrusions of the inner rubber layer that erupt from the stitches of the blade reinforcing layer cause unevenness on the outer rubber layer.

In addition, since the hose is preheated and vulcanized with a knitted paper blade reinforcing layer on the outer surface of the inner rubber layer, and then the main heat vulcanization is performed, the adhesion between the inner rubber layer and the blade reinforcing layer is not impaired at all. A part of the inner rubber layer is made to protrude on the outer surface of the blade reinforcing layer as a protrusion using sulfur, and then the outer rubber layer is coated on the outer surface, filling in the spaces between the protrusions, so that the inner rubber layer and the outer rubber layer form a role. A rubber hose with good adhesion between layers can be obtained.

Moreover, 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 reinforcement layer can be manufactured at low cost. You can.

Claims (1)

[Claims] 1. A step of braiding a fiber braid reinforcing layer on the outer surface of the unvulcanized inner rubber layer, and a preheating and vulcanization step of heating the hose to near the vulcanization temperature of the rubber hose to almost complete fiber contraction and rubber flow. A method for producing a rubber hose having a fiber braid reinforcing layer, comprising the following steps: after coating with an outer rubber layer, main heat vulcanization is performed.