JPH0471826A - Silicone rubber hose and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture deformation-free silicone pressure hose in continuous form by atmospheric vulcanization without the expansion of adhesive layer by a method wherein jacket layer made of silicone rubber is covered on the outside, on which adhesive made of liquid thermosetting silicone rubber is applied before and/or after the formation of reinforcing thread layer, of inner tube layer made of vulcanized silicone rubber and finally the jacket layer is vulcanized. CONSTITUTION:Silicone rubber inner tube layer 1, which is extruded from an extruder or the like and vulcanized, is delivered by a lead-in device 2 so as to be firstly passed through a container 3, in which liquid thermosetting silicone rubber adhesive is housed, in order to be adhered by adhesive made of liquid thermosetting silicone rubber. In succession, reinforcing threads 5 are wound round the inner tube layer with a braider or spiral machine 4 so as to be passed through a vacuum tank 8, on both sides of which packings 6 and 7 are equipped, and then vulcanized liquid thermosetting silicone rubber in a vulcanizing device 9 and taken up. Next, the resultant inner tube layer is fed to a jacketing extruder so as to form jacket layer and finally the jacket layer is vulcanized. As the vulcanizing device 9 and a vulcanizing device after the formation of the jacket layer, an atmospheric vulcanizing device may be used.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a pressure-resistant hose made of silicone rubber for use in transporting foods, etc., which is made of an inner tube layer and an outer tube layer made of silicone rubber, and a reinforcing yarn layer provided between them. Regarding.

<Prior Art> Conventionally, an adhesive prepared by dissolving noricorn rubber in a solvent has been used to bond and integrate the inner and outer tube layers made of noricorne rubber and the reinforcing thread layer located therebetween.

In this case, a step of drying the adhesive is required during manufacturing, and the solvent tends to remain during the process, causing foaming during vulcanization and other hose manufacturing. To prevent foaming, there are methods to apply external pressure during vulcanization, specifically steam vulcanization using a vulcanizing can, or inserting an iron core into a hose and placing it in a mold for press vulcanization. methods are being used.

<Problems to be Solved by the Invention> The steam vulcanization method described above has a limit on product length because it vulcanizes a fixed length of hose by winding it up in a spiral shape in a tray-shaped container with a flat bottom. Moreover, the part of the hose that comes into contact with the bottom of the tray deforms due to its own weight. In addition, products using a mold are shorter than steam vulcanized products, and tightening of the mold is dangerous due to pressure.

The present invention eliminates the above-mentioned disadvantages and enables the production of a long pressure-resistant glue corn pouch without deformation by normal pressure vulcanization without foaming the adhesive layer.

Means for Solving the Problems> The present invention forms a reinforcing thread layer on the outside of an inner tube layer made of vulcanized silicone rubber, and the reinforcement thread layer contains a solvent before and/or after the reinforcing thread layer is formed. The method is characterized in that an adhesive made of liquid thermosetting silicone rubber is applied, and an outer covering layer made of noricorn rubber is covered with the adhesive before or after vulcanization, and the outer covering layer is then vulcanized. A reinforcing thread layer is located between the silicone rubber inner pipe layer and the same rubber outer covering layer, and the three parts are bonded together with an adhesive. There is a silicone rubber hose characterized in that it is made of molded silicone rubber.

The noricorn rubber used in the present invention is generally a heat-vulcanized noricorne rubber whose main raw material is a highly polymerized orcanoborin loxane having silicon-oxygen bonds in its main chain, which is usually referred to as noricorne cam or silicone raw rubber. In particular, for use in hose pipes, it is used to knead reinforcing fillers such as synthetic silica, bulking fillers such as crushing glue, and other additives, and it is also compounded with organic peroxide as a vulcanizing agent. It is. Among these, the liquid thermosetting type Noricone is selected from those exhibiting a liquid state at room temperature.

The hose of the present invention can be manufactured continuously as described below. FIG. 1 is a schematic diagram of an example of the process.

In FIG. 1, a silicone rubber inner tube layer 1 extruded by an extruder or the like and vulcanized is sent out by a feeding device 2, and first passes through a container 3 containing a liquid thermosetting silicone rubber adhesive. An adhesive consisting of liquid thermosetting noricorn rubber 1 is adhered to the outer surface of the inner tube layer 1. Next, a reinforcing thread 5 is wrapped around the inner tube layer using a plague or spiral manono 4, and a packing 6.
7 and passed through a vacuum tank 8, the liquid thermosetting noricorn rubber was vulcanized by a vulcanizer 9, and taken off. Next, an outer coating layer is formed using an extruder for external waves (not shown), and vulcanization is performed. Both the vulcanization device 9 and the vulcanization device after forming the envelope may be an atmospheric pressure vulcanization device.

When the pressure is reduced within 1 g by a vacuum pump (not shown), the liquid thermosetting noricorn rubber adhesive attached to the outer surface of the inner tube layer 1 rises to the surface due to the tension of the reinforcing threads 5. This adhesive is smoothed out by the packing 6.7, or at this time it traps air, so by passing it through a vacuum tank 8, the air and the air contained in the reinforcing threads 5 are degassed.

The diameter of the packing is made larger on the inlet side 6 than on the outlet side 7. As a result, the surface of the reinforcing thread is also covered with silicone rubber, and the reinforcing thread can be securely fixed. Reinforcement thread 5
If the stitches are so dense that the adhesive does not rise to the surface, a tank containing adhesive may be used instead of the vacuum tank 8, and the adhesive may be further applied after the reinforcing yarn layer is formed. If the reinforcing yarn layer is rough, an adhesive may be applied after forming the core layer. The liquid thermosetting noricorn rubber to be placed in the container 3 is preferably degassed.

You can also use a vacuum pump to reduce the pressure in container 3.)

The inner tube can also be supplied by performing extrusion molding and vulcanization using an inner tube extruder on the same line.

In the first aspect of the present invention, the reinforcing yarn layer is formed, and the adhesive layer is directly introduced into an extrusion coating device after vulcanization to form an outer coating layer, and the outer coating layer is coated under normal pressure. Vulcanization can be carried out, or the adhesive can be introduced into an extrusion coating apparatus in an unvulcanized state to form an outer coating layer, and then the entire adhesive can be vulcanized under normal pressure.

Most silicone rubbers have two types: primary vulcanization and secondary vulcanization.
However, if a brand that does not require secondary vulcanization is used, the manufacturing process can be shortened and the entire process from forming the inner tube to forming the outer cover layer can be completed.

<Example> To 100 parts by weight of Tou μ Noricone S E 1187U, 50 parts by weight of 2.4 dichlorhenyl peroxide
A mixture of 1.3 parts by weight of paste with a concentration of 1.3% was extruded by a conventional method into a tube with an inner diameter of 9.5mm and an outer diameter of 12.5mm, passed through a vulcanizer, and subjected to second vulcanization at 250°C for 3 minutes. Then, secondary vulcanization was performed at 150°C for 10 hours. A liquid noricorn rubber, which is a mixture of 100 parts by weight of TOμ Silicone 5RX-643 and 0 parts by weight of hardener TOμ Silicone S RX-6265, is applied to this, and 1000 d of ester filament yarn is braided using a 24-stroke braiding machine.
Further, the above liquid noricorn rubber was applied and passed through a vulcanizer to be vulcanized at 160°C for 3 minutes.

This was applied to a conventional extruder for forming an outer cover, covered with the above-mentioned silicone rubber, and vulcanized at 250°C for 3 minutes at normal pressure, followed by secondary vulcanization at 150°C for 15 hours, with an outer diameter of 15. 5
A pressure-resistant hose of mm was obtained. In the obtained hose, no foaming was observed in the adhesive layer, and the adhesion was strong.

Comparative Example> Solution-type Noricone Rubber S E 1185U as adhesive
Same as the example except that 13 parts by weight of a 50% concentration paste of 2.4 dichlorobenzoyl peroxide was mixed with 100 parts by weight, and the mixture was dissolved in xylene or toluene to give a solid content of 30%. using the same materials,
A hose was formed in a similar manner. The adhesive film itself foams due to the evaporation of the solvent contained in the solution when it dries and hardens after the adhesive has been applied, resulting in severe foaming during vulcanization after the outer coating is formed, and therefore the adhesive It was weak. Also, the smell of the solvent does not go away easily.

<Effects of the Invention> According to the present invention, no solvent is used for the adhesive that integrates the inner tube layer, the reinforcing yarn layer, and the outer covering layer, so that the forming of the hose,
In particular, there is no foaming due to residual solvent during vulcanization, the adhesive strength of the three layers is strong, and there is no residual solvent odor in the product. Furthermore, there is no need for a dryer during the process, and there is no need to worry about environmental pollution. Furthermore, since the method of the present invention allows continuous vulcanization under normal pressure, dimensional accuracy is good and long products can be manufactured continuously.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of an apparatus for implementing the method for manufacturing a pressure-resistant hose made of silicone rubber according to the present invention. 1 is an inner tube layer, 3 is an adhesive container, 5 is a reinforcing thread, and 9 is a vulcanizing device.

Claims (1)

[Claims] 1) A liquid thermosetting silicone rubber in which a reinforcing thread layer is formed on the outside of an inner tube layer made of vulcanized silicone rubber, and does not contain a solvent before and/or after the reinforcing thread layer is formed. 1. Production of a silicone rubber hose, characterized by applying an adhesive consisting of the above, coating the adhesive with an outer cover layer made of silicone rubber before or after vulcanization of the adhesive, and then vulcanizing the outer cover layer. Method. 2) A hose in which a reinforcing thread layer is located between a silicone rubber inner tube layer and the same rubber outer cover layer, and the three are bonded together with an adhesive, characterized in that the adhesive is made of liquid thermosetting silicone rubber. silicone rubber hose.