JPS586618B2 - Method of vulcanizing elastomer articles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for vulcanizing an elastomer article. Specifically, after setting a vulcanizable elastomer article in a vulcanization chamber, the vulcanizable article is vulcanized through a bladder or without a bladder. The elastomer article is vulcanized by supplying a mixed fluid of a high-pressure, low-heat-capacity gas and a high-heat-capacity thermal fluid into the curing chamber at a pressure and temperature appropriate for vulcanization while being controlled by a controller with a built-in microcomputer. It is about the method.

Up to now, various methods have been employed as vulcanization methods for elastomer articles.

In particular, JP-A-51-64579 proposes a so-called gas vulcanization method.

In this method, a vulcanizable elastomer article placed in a vulcanization chamber is first supplied with a relatively low pressure, high heat capacity thermal fluid, such as steam, into the vulcanization chamber to cure the elastomer article. and then, in a second step, a gas having a higher pressure and lower heat capacity than the thermal fluid is introduced to complete the vulcanization of the article.

However, this method has the problem that there is a limit to the control of the pressure and temperature of the relatively low-pressure, high-heat-capacity thermal fluid supplied in the first step to cure the elastomer article, making it impossible to achieve sufficient curing.

That is, saturated steam is generally used as a fluid with high heat capacity, but since this saturated steam has a proportional relationship between temperature and pressure, in the conventional method, (1) the pressure is too low. As a result, the air accumulated between the mold and the article to be vulcanized cannot be discharged satisfactorily, and therefore machining damage (bareness) is likely to occur on the surface of the article to be vulcanized.

(2) The temperature becomes too high and the article to be vulcanized becomes over-vulcanized, resulting in rubber deterioration and cord deterioration.

It has the following drawbacks.

The present invention was obtained as a result of studies to eliminate the above-mentioned drawbacks in conventional gas vulcanization. By feeding a possible elastomer article into the vulcanization chamber, the processed surface is not damaged and proper vulcanization is completed.

The present invention will be explained below with reference to the drawings.

FIG. 1 is an explanatory diagram of the vulcanization method of the present invention, in which a tire A is used as an example of a vulcanizable elastomer article, and in the figure, the elastomer is loaded into a vulcanization chamber, that is, a mold, through a bladder. of the tire A? Indicates a state in which sulfur has progressed considerably.

In FIG. 1, 1 is a bladder (in a state in which the outer peripheral surface is expanded by fluid supply), 2 is an upper mold, and 3 is a lower mold.

A tire A is interposed between the bladder 1 and the mold 23.

5 is a mixer, and this mixer 5 contains steam S and gas G.
The mixed fluid is supplied to the prader 1 inside the vulcanization chamber.

6 is a pressure transmitter, T is a temperature sensor, and 8 is a controller with a built-in microcomputer.

9 is check valve V, V2, V3 is steam S, gas G exhaust E
This is an automatic control valve attached to each pipeline.

The controller 8 constantly senses the pressure in the mixed fluid supply path from the mixer to the vulcanization chamber with the pressure transmitter 6, and the temperature sensor 7 in the exhaust gas E discharge path. and the controller 8
Since the appropriate pressure and temperature conditions for vulcanization of the article to be vulcanized are preset in the vulcanizer, each automatic control valve is set so that a mixed fluid with the necessary pressure and temperature can be sent to the vulcanization chamber accordingly. It can be operated to adjust the flow rate of steam or gas to the mixer and to exhaust the air.

This will be explained in more detail in the case where, for example, a tire of size 1000 to 20 is used as the article to be vulcanized.

The vulcanization conditions for tire vulcanization of sizes 1000 to 20 are in the range of temperature 140 to 200°C and pressure 15 to 30 kg/cm'; for example, the conditions of 170°C and 28 kg/cm' are preset into the controller No. 8. First, green tires are loaded into a mold, automatic control valves V, , V2 are opened, V3 is closed, and steam S and gas G are supplied to the mixer 5.

Then, the mixed fluid mixed in the mixer is supplied into the mold.

This starts vulcanization. During the heating process using the mixed fluid, the pressure and temperature of the mixed fluid are constantly input to the controller, and the previously applied 170°C - 2 8 kg
The opening degree of the steam and gas automatic control valves V, V2 is automatically adjusted according to the conditions of /cm'.

For example, when talking about the control when the pressure and temperature of mixed sulfur are too high or too low, if only the temperature is below the standard level, open V1, V2 and V3, and if the pressure is too high above the standard level and the temperature is too low, open V1, V2 and V3. When the level is insufficient than the standard level, open V3 to exhaust the mixed fluid first, then open V3.
All you have to do is close V, V2 and inject steam and gas.

When only the pressure is insufficient than the reference level, V2 may be opened while V, ., V3 are closed to supply a large amount of gas to the mixer.

In the present invention, the mixer used to mix steam and gas is not particularly limited, but for example, as shown in FIG. 2, gas G is introduced from 11, and steam S from 12 is caused by the gas pressure. An ejector may be used that has a structure in which it is sucked in, mixed with a gas flow, becomes a mixed fluid G&S, and is injected from the discharge port 13.

In this way, the tire vulcanization (heating process) is completed by supplying the mixed fluid under the above conditions for 40 to 50 minutes.

After the heating process is completed, the automatic control valve V3 leading to the exhaust port is opened, and the steam and gas control valves V, V2 are closed to exhaust the mixture, and the heating process is completed.

After the heating step, the entire vulcanization step is completed through conventionally known steps such as a cooling water step.

Incidentally, examples of elastomer articles employing the vulcanization method of the present invention include, in addition to the tires described as examples, fenders, sleeves, hoses, and the like.

As described above, the vulcanization method of the present invention includes creating a mixed fluid of steam and gas using a mixer and supplying this into a vulcanization chamber to vulcanize the article to be vulcanized, and vulcanizing the mixed fluid. This feature uses a controller with a built-in microcomputer to constantly set and maintain optimal pressure and temperature conditions, allowing high pressure to be obtained from the early stages of vulcanization without raising the temperature excessively. As a result, it is possible to prevent over-vulcanization such as processing damage to the surface of the vulcanized object, rubber deterioration, cord deterioration, etc. due to excessive or insufficient pressure or temperature.

Furthermore, since the amount of heat is constantly controlled according to the set conditions, it also has the effect of preventing wasteful consumption of energy.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an explanatory diagram showing the vulcanization method of the present invention, and FIG. 2 is a longitudinal sectional view of an ejector that is a mixer.

Claims (1)

[Claims] 1. After setting a vulcanizable elastomer article in a vulcanization chamber, a mixed fluid of a high-pressure, low-heat-capacity gas and a low-pressure, high-heat-capacity thermal fluid is supplied into the vulcanization chamber to cure the elastomer. A method for vulcanizing an elastomer article, the method comprising vulcanizing the article. 2. The temperature and pressure of the supplied mixed fluid are maintained at desired levels by controlling appropriate flow rates of each of the gas and thermal fluid using a controller incorporating a microcomputer. Vulcanization method as described.