JPH0476027A - Production of sponge - Google Patents

Abstract

PURPOSE:To obtain a sponge having any desired uniform sectional shape and foamed state by extruding a material prepared by mixing a chlorosulfonated PE with a vulcanizer, etc., and simultaneously vulcanizing and foaming the extrudate according to a specified operation. CONSTITUTION:A process for producing a sponge by extruding a material prepared by mixing a chlorosulfonated PE with a vulcanizer, a blowing agent, a filler, etc., and vulcanizing and foaming the extruded unvulcanized rubber material, wherein the unvulcanized material is continuously guided to a vulcanization apparatus and simultaneously vulcanized and foamed by gradually raising the temperature between the inlet of the apparatus and its exit.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industry> Second Field of Application The present invention relates to a method for continuously producing chlorosulfonated polyethylene (hereinafter referred to as C3M) sponge by extrusion molding.

<Prior Art> C8M Subo Sponge has excellent weather resistance, seawater resistance, and color stability, as well as a good texture. Therefore, they are generally manufactured by press molding.

In the case of press molding, unlike continuous extrusion vulcanization, the decomposed gas of the blowing agent can be sealed (retained) by the mold and press pressure, so it is possible to commercialize the product even if the balance between vulcanization and foaming is disrupted to some extent.

In response to this, attempts have been made to manufacture sponge products by extrusion molding and continuous vulcanization of C8M compounds. Since there is no means to seal the foaming gas into the rubber during vulcanization using press pressure, materials with short solubility times are used to speed up vulcanization and reduce gas generation due to vulcanization and decomposition of the blowing agent. It is necessary to strike a balance, but achieving this balance has traditionally been considered extremely difficult. In addition, the +414C combination with a short sea urchin scorch time mentioned above is
Since it is unvulcanized during storage, its physical properties change, resulting in poor storage stability.

Therefore, when manufacturing C8M sponge products, it is possible to mold them with a relatively safe mixture of scorch, so it is possible to mold them into tubes, rods, or strings with irregular cross sections, which should originally be extruded products. Manufactured by mold. In extrusion, the longer the scorch is, the slower the vulcanization is (the longer the scorch is, the slower the vulcanization is).The decomposed gas from the blowing agent cannot be caught, and the sponge cells penetrate through to create an open-cell sponge.At the same time, the skin layer also penetrates, resulting in a complete sponge. Hateful.

However, in production methods that use molds, for example, when producing products with low water absorption, molds are required for primary vulcanization and secondary vulcanization, and the rubber material used during primary vulcanization is Since the filling rate requires 100% of the mold volume, preforming with accurate dimensions and shape is required, and in addition, the vulcanization time for primary and secondary vulcanization must be short in seconds and at accurate temperatures. If not controlled, there will be problems such as variations in foaming state and size, and accuracy is also required in the design of mold dimensions.

If you want to obtain a sponge with a high water absorption rate, use a single mold to make rubber v.
The sponge with the target performance is obtained by adjusting the filling rate of I-gain in various ways from 50% to 80%, but since it requires preheating of the rubber material, heating for vulcanization and foaming, and heating in stages, accurate Temperature control is required and manufacturing takes time.

Furthermore, with the mold method, it is impossible to produce long products, and in addition, molds for primary and secondary vulcanization are used, making it impossible to produce irregularly shaped products with complex shapes. Have difficulty.

<Problems to be Solved by the Invention> The present invention involves extruding a C3M unvulcanized rubber material using an extruder, and then continuously vulcanizing and foaming it to create a homogeneous, arbitrary cross-sectional shape and foaming state (water absorption rate). ) It is an object of the present invention to provide a method for easily producing a C8M sponge product having the following properties.

Means for Solving the Problems The present invention provides a method for producing a chlorosulfonated polyethylene sponge in which a material prepared by blending chlorosulfonated polyethylene with a vulcanizing agent, a filler, etc. is extruded, and vulcanization and foaming are performed continuously. , the unvulcanized rubber material extruded from the extruder is continuously guided to a vulcanizer, and the temperature is sequentially adjusted between the inlet and outlet of the vulcanizer, preferably within the range of 70 to 230°C. This is a method for producing a chlorosulfonated polyethylene sponge, which is characterized by heating and vulcanization and foaming at the same time.

In the C8M unvulcanized rubber rubber material for forming the sponge in the present invention, the vulcanizing agent and vulcanization accelerator are generally magnesium oxide, pentalite #300, northotolylguanine, and pentamethylene diuram tetrasulfate. Although fine adjustments are made depending on the vulcanization conditions, the optimum amount to be added is determined based on specific gravity, hardness, sponge texture, etc.

In addition, as fillers and reinforcing agents, depending on the performance of the sponge to be obtained, calcium carbonate, MT carbon, etc. are used for sponges with a soft texture, and in order to obtain high reinforcement properties for use in shoe soles etc. For example, silica, FEF carbon, etc. are used, and in order to obtain an extruded product that takes surface texture into consideration, Mistron paper, Hisolite, etc. are recommended.

In the present invention, as a characteristic of the unvulcanized rubber material for extrusion, in order to minimize deformation of the unvulcanized state in the vulcanization tank, the Mooney viscosity MLI + 4100°C may be set to 50 to 70. Preferably, for this purpose C8M Aizuki Gray 1.
Using high viscosity and low viscosity 01, adjust the amount of filler and plasticizer (nooctyl phthalate) used, and then adjust the amount of the vulcanizing agent and vulcanization accelerator mentioned above to control the product during vulcanization. We will continue to improve the deformation of

The scorch time of the material is J, -2-chometer T,
25-3.5 minutes at o-tar 125°C, vulcanization time iJ T S R Gulastometer T-1 at 160°C
0 value is 0'A~045 minutes, 'I''-90 value is 1.5~2
0 minutes! This is a desirable value considering the specific gravity, foaming, and deformation of the product. If the scorch time is long, a good sponge cannot be obtained as described above.

Next, as a foaming agent to obtain the sponge, the rubber temperature is 1500.
A material capable of decomposition and gasification at 0 to 160°C is used. For example, to obtain a sponge with a specific gravity of 0.20 to 0.25, 5 parts of the blowing agent rosopentamethylene tetramine (DPT) and urea and its derivatives (
Use 5 parts of Selton N1)).

The amounts of these blowing agents and foaming aids to be used are determined by the vulcanization temperature, how the accelerator is used, the vulcanization speed, and the type of vulcanization equipment.

In the present invention, it is important that the unvulcanized rubber material is maintained under conditions that do not cause scorch and foaming until it is extruded, and that it is vulcanized and foamed all at once in the vulcanization zone.

In the kneading process of rubber materials, the vulcanization characteristics of sponges, not just C3M, are limited by the scorch time as described above, so the roll surface/! Keep the temperature at 71 degrees below 50 degrees Celsius, and cool the dispensed sheets (preferably below 130 degrees Celsius) after mixing is complete.Also, there is a ribbon removal process to make it easier to feed the extruder, but in this process as well. Roll surface temperature to 50
It is desirable to keep the temperature below 30°C and to cool the ribbon-shaped rubber material to below 30°C. In addition, in the case of +A'#4, where there is a risk of scorching due to heat history by including the rebonding process, the cooled portioned sheet after kneading is pelletized with a pellet machine and then fed into the extruder. Also incorporate methods to do so. In addition, as mentioned above, unvulcanized rubber mixed with a vulcanizing agent and a vulcanization accelerator is mixed on the day of use. It is advisable to use it within your eyes.

Extrusion (2 upper culms (J, temperature setting conditions and viscosity low 1
・Due to heat generation, it is necessary to select the most advantageous conditions for scorch, for example, the Fee 1 zone, Norinder zone, head section (J is set at around 50℃, and the die section is set at around 50℃. The temperature is set at approximately 70°C.This condition results in a Mooney viscosity that generates less heat, which is advantageous for soot 1-di, and at the same time increases the extrusion rubber temperature to a temperature that is advantageous for foaming (
80℃). If the feed zone and norinter zone are lowered to 40° C., particularly 45° C. or lower during extrusion, the viscosity of the dough will increase and heat will be generated in the extruder, causing problems in foaming due to shortening of scorch time. Further, if the feed zone and ring zone are set at 60° C., especially 55° C. or higher, the temperature of the dough becomes too high, which causes a shortening of the scorch time.

The vulcanizer installed following the extrusion process is a hot air type, high frequency type, far infrared type, etc., or a combination thereof.

In the present invention, after extruding C9M unvulcanized rubber i:1 into the required shape using an extruder, it is added to the vulcanizer using a single or combined vulcanizer. The material is heated to a low temperature, and then the temperature is gradually increased in the vulcanizing device, and the material is vulcanized to a high temperature at the exit L1 portion of the vulcanizing device, during which foaming is performed simultaneously with vulcanization.

It is better to increase the temperature in the vulcanizer in stages by dividing the heating zone of the machine into multiple parts.
It is ¥r profit. The foaming state of the sponge can be easily changed by setting the temperature of each zone. For example, 171 parts (first zone) of the vulcanizer is 10
The temperature in the tank is maintained at 0 to 140°C, preferably 110 to 130°C, and the temperature in the tank is gradually increased until the second zone is heated to 130°C.
~150℃, the third zone is maintained at 155-165℃, and the fourth zone is maintained at 175-180℃. It is possible to obtain a
0℃, 3rd zone 160-170℃, 4th zone 1
By setting the temperature between 80 and 230℃, the water absorption rate can be increased to 5.
% more sponge can be obtained.

On the other hand, if the heating conditions are maintained uniformly at, say, 140°C from the inlet to the outlet of the equipment, the blowing agent will begin to decompose when the rubber temperature reaches around 130°C, but vulcanization of the rubber will not proceed. The decomposed gas cannot be caught in the rubber, and the gas escapes from the rubber layer, making it impossible to obtain a sponge. On the other hand, if the temperature inside the tank is maintained at 180°C, the surface of the rubber will be vulcanized before the blowing agent decomposes, and the decomposed gas of the blowing agent will move toward the inside of the duplex, making it impossible to obtain a sponge with a low specific gravity. The cells also become non-uniform. The water absorption rate was determined by submerging the sample in water, keeping it under reduced pressure for 3 minutes at 125 mm and 11 g, returning the reduced pressure to normal pressure, leaving it in water for 3 minutes, taking it out, wiping off the water droplets on the surface, measuring the weight, and calculating the rate of weight change. This is the numerical value obtained using the method of calculation.

Next, a specific method of the present invention will be explained using examples.

Example 1 First, prepare an unvulcanized rubber material having the following composition.

The kneading, sheeting, etc. of this material are carried out at a temperature of 50° C. or lower.

Denka C3M390 50 parts by weight Denka C3M350 5o manufactured by Denki Kagaku Kogyo Co., Ltd.
Stearic acid manufactured by Denki Kagaku Kogyo Co., Ltd.
]〃Magnesium oxide 4〃Calcined ray 5o〃Light calcium carbonate
2 o Dinitrosopentamedylene 5 Tetramine (DPT, manufactured by Sankyo Kasei Co., Ltd.) Foaming aid Selton NP 5 Pentalit #3006, manufactured by Sankyo Kasei Co., Ltd. Diorthotolylguanidine 1 Dipentamedylene Thiuram tetrasulfide 〃 Diocdylphthalate io 2 go
Total 233〃The unvulcanized rubber material was kept at approximately 50℃ in the extruder, and the temperature was 70℃.
A rubber material was extruded into a desired cross-sectional shape from the head section of 'C, and then continuously vulcanized and foamed under the conditions shown in Table 1.

The speed in the vulcanization tank is 1.5 m/m when the product is 100 g/m.
minute, and in the case of 50 g/m, it was set to 3.0 m/min.

Under the setting condition ■, the first and second zones are set as low temperature regions,
Rapidly raise the temperature of the 3rd zone and the 4th zone to 191'C
A sponge with a water absorption rate of 10.8% can be obtained.

Next, as in setting condition 2.3, the first zone was heated to 120°C and 13°C.
The temperature was set at 2°C. By increasing the temperature smoothly and linearly in the third zone and keeping the fourth zone below 180'C, sponges with water absorption rates of around 0.5% and 3.4% can be obtained.

Note that when the temperature is 130° C. or higher, as in the first zone of setting condition 4, the balance between surface vulcanization and foaming is lost, resulting in a high specific gravity and a uniform cell structure that is difficult to form.

In addition, if the temperature inside the entire vulcanization tank is set to 400C as in setting condition 5, the blowing agent will start to decompose when the rubber temperature exceeds 430C, but since the rubber is not vulcanized, the decomposed gas will be released into the rubber. Because it penetrates the skin layer and escapes, the surface does not have a uniform cell structure, resulting in a sponge with high specific gravity and water absorption.

In addition, if the temperature inside the entire vulcanization tank is set to 180°C as in setting condition 6, the skin layer of the rubber is vulcanized first, so the skin layer cannot be expanded by gas pressure, so the foam structure on the outer surface is insufficient and the specific gravity is high. This results in an uneven sponge.

Example 2 Sponges were made from the same materials as in Example 1 using a combined vulcanization device consisting of a high frequency vulcanizer and a hot air vulcanization tank under the conditions illustrated in Table 2.

In a dual vulcanizer of high frequency and hot air vulcanizer, the temperature of the comb at the output 1'l of the high frequency vulcanizer is adjusted to the lfh degree of the first zone of the single hot air vulcanizer of Example 1. The same results can be obtained with a hot air vulcanization device.Similar results can also be obtained with the combined use of a far infrared vulcanization device and a hot air vulcanization device.

After undergoing the continuous vulcanization and foaming process under the conditions described above, the product undergoes cooling, take-up, and winding processes to become a product.

In the embodiment, a case where the number of heating tanks is 3 or 4 zones is illustrated, but the embodiment of the present invention is possible if there are 2 or more zones.

<Functions and Effects> According to the present invention, long sponge products with stable quality can be efficiently manufactured. In addition, when making sponges with different water absorption rates, by setting the temperature of each zone, especially the first zone and the final zone, it is easy to make sponges with low to high specific gravity and low to high hardness. Also, products with complex cross-sectional shapes and irregular shapes can be easily produced.

The sponge produced by the present invention is bright in color, has excellent weather resistance and seawater resistance, and has better physical properties than other rubber-based sponges, strong skin strength, and good texture. It has characteristics.

Claims (1)

[Claims] 1) Chlorosulfonated polyethylene with a vulcanizing agent, a blowing agent,
In the manufacturing method of chlorosulfonated polyethylene sponge, in which a material containing fillers, etc. is extruded, vulcanized, and foamed continuously, the unvulcanized rubber material extruded from the extruder is continuously guided to the vulcanizer. A method for producing a chlorosulfonated polyethylene sponge, characterized by heating the sponge by successively increasing the temperature between the inlet and the outlet of a vulcanizer, and performing foaming at the same time as vulcanization. 2) Before the extruder during the kneading process, the unvulcanized rubber is approximately 5.
The temperature from the feed zone to the head of the extruder is maintained at approximately 40 to 60 °C, the head temperature is maintained below the foaming temperature, and the temperature in the vulcanizer is approximately 80 to 230 °C. 2. The method for producing a chlorosulfonated polyethylene sponge according to claim 1, wherein the heating is performed by sequentially increasing the temperature within a range. 3) The temperature at the inlet of the vulcanizer is 100 to 140°C,
The method for producing a chlorosulfonated polyethylene sponge according to claim 1 or 2, wherein a sponge having a water absorption rate of less than 5% is continuously produced by controlling the temperature at the outlet to 180° C. or less. 4) A sponge having a water absorption rate of 5% or more is continuously manufactured by controlling the temperature at the inlet of the vulcanizer to 100°C or less and the temperature at the outlet from 180°C to 220°C. A method for producing a chlorosulfonated polyethylene sponge as described in .