JPS6037137B2 - Rubber composition with elasticity - Google Patents

Description

[Detailed Description of the Invention] The present invention crushes the rubber shoulders of old tires to form vulcanized rubber powder, which is then bound with a special type of thermoplastic elastomer to have elasticity and flexibility. The present invention relates to obtaining rubber compositions.

Conventional methods for disposing of old tires include turning them into recycled rubber and separating and extracting each component by thermal decomposition.

In addition, vulcanized rubber powder is used as it is, but the quantity is small. Various methods have also been devised to utilize vulcanized rubber powder as molded products. Specifically, rubber latex is added as a binder to vulcanized rubber powder and dried and vulcanized, it leaks into unvulcanized rubber to form a vulcanized rubber composition, or the vulcanized rubber powder itself is compressed and vulcanized. There is a method of vulcanization molding, and a method of integrally molding a mixture of ethylene and vinyl acetate copolymer resin as a binder to vulcanized rubber powder. Among these usage methods, the recycled rubberization method is a treatment method that has been widely, rationally, and industrially processed and established. At present, old tires, such as truck tires and bus tires, are still mainly processed, and passenger car tires are hardly converted into recycled rubber. Although the treatment method of separating and extracting each component using pyrolysis is scientific and will be of great significance as a resource-saving measure in the future, it is expensive for equipment. On the other hand, methods of utilizing rubber powder in powder form have been practiced for some time, and are used as road reinforcement materials and soil improvement materials, but the amount used is small. The method of joining vulcanized rubber powder using a binder to make a molded product is as follows.
This method requires complicated steps such as drying the rubber latex or plastic emulsion and vulcanizing the rubber latex, which poses many problems industrially. The method of mixing vulcanized rubber powder into unvulcanized rubber is also a method that is actually used, but it is difficult to distinguish between the use of vulcanized rubber and manufacturing equipment, etc., because mixing of vulcanized rubber powder with other vulcanized rubber powder is not preferred. It is inconvenient and requires an additional vulcanization step.

Next, a method of obtaining a rubber molded product by compression molding the vulcanized rubber powder itself has been devised, but the molding conditions are difficult and there are many restrictions on the shape of the molded product. Furthermore, a method to obtain rubber molded products by binding vulcanized rubber powder with ethylene/vinyl acetate copolymer resin has been devised and announced, but the present invention has better workability, lower equipment costs, and a simpler process than this method. It has great significance in that it is possible to mass-produce molded products with a good balance of strength, elasticity, and flexibility at low cost by combining the following.

That is, in order to increase the cohesive force of the polybutadiene resin or butadiene-styrene floc copolymer, which is the binder of the diluted rubber powder, when heated, 1 to 20 parts by weight of rubber is added. Furthermore, it is free to add fillers, anti-aging agents, softeners, fatty acids, etc. that are normally added to rubber. However, this invention is characterized by not adding sulfur or a crosslinking agent, and having the above-mentioned excellent physical properties without being crosslinked. Therefore, cut shoulders, products with insufficient thickness, etc. can be reheated and rerolled for use. Applications include cushioning materials, vibration isolation materials,
It can be used as a sound-absorbing material, flooring material, etc. for Hironaka's largest products.

Next, the main raw materials used in the present invention will be explained.

First, the vulcanized rubber powder is made by pulverizing waste tires, for example, by roll crushing or freezing crushing, and has a particle size of 10 mesh to 80 mesh, preferably 20 mesh to 60 mesh.
Mesh is easy to use industrially.

The materials can be used regardless of the type of truck, bus, or passenger car. What is polybutadiene resin? RB#810 manufactured by Japan Synthetic Rubber ■
RB#820 corresponds to this. What is butadiene/styrene block polymer?Califlex #1 from Shell Chemical ■
101, #1107, Toughprene A manufactured by Asahi Kasei Co., Ltd., Solbren #400 #47 ¥ sold by Asahi Kasei ■, etc. correspond to this. 1 to 20 parts by weight of rubber, such as polyisobutylene rubber, phthyl rubber, etc., per 10 parts by weight of polybutadiene resin or butadiene-styrene block copolymer.
By replacing it with weather-resistant and cohesive rubber such as chloroprene rubber and butyl recycled rubber, the cohesive force during hot conditions such as cross-tracking work and rolling work increases, improving productivity and improving film resistance.

The mixing ratio of powdered rubber and binder can vary widely depending on the particle size of the powdered rubber and the type of binder, and further depending on the purpose, but approximately 100 to 60 parts by weight of powdered rubber to 100 parts by weight of binder produces high strength. A rubber composition having both high elasticity and flexibility can be obtained.

Next, examples will be shown to specifically illustrate the composition of the present invention, but
The manufacturing method is not limited to the scope of the examples, and the physical properties are summarized in Table 1.

Example 1 Tire Calo sulfur rubber powder 40-60 mesh 20 parts by weight RB#820 manufactured by Japan Synthetic Rubber ■ 10
Weight part: Vistanex L-1 manufactured by Exxon Chemical ■
00 1 parts by weight Total 31 parts by weight Approximately 11
The mixture is kneaded for about 15 minutes in a pressure kneader at 0 qO, and then passed through rolls of about 110 qo, which have the desired gaps in advance, to obtain a rubber sheet of the desired thickness.

Example 2 Tire vulcanized rubber powder 40-60 mesh 20 parts by weight Toughprene A manufactured by Asahi Kasei Corporation IO Kame parts by weight Vistanex L-100 manufactured by Exxon Chemical ■
A total of 5 parts by weight of 305 parts by weight of about 120 qo was kneaded in a pressure kneader for about 15 minutes, and in the same manner as in Example 1.
By passing it through a roll at about 120° C., a rubber sheet with a desired thickness can be obtained.

Example 3 Tire Calo sulfur rubber powder 40-60 mesh 20 parts by weight Sorprene #475 manufactured by Asahi Kasei Industries 10 parts by weight Neoprene WHV manufactured by Showa Neoprene ■
Total parts by weight of I: 31 parts by weight at approximately 140℃
The mixture is mixed in a pressure kneader for about 20 minutes and passed through the gaps between about 14,000 rolls to obtain a rubber sheet of the desired thickness.

Example 4 Tire flow rubber powder 40-60 mesh 30 parts by weight RB#820 manufactured by Japan Synthetic Rubber ■ 10
Part by weight made by Japan Synthetic Rubber 11R#065
Total parts by weight of 1: Approximately 12 parts by weight of 41
Knead for about 15 minutes in a pressure kneader at 0°C, then leave it as is) about 1
A rubber sheet of desired thickness is obtained by passing between 2000 rolls.

Example 5 Tire Calo Sulfur Rubber Powder 40-60 mesh 50 parts by weight RB#820 manufactured by Japan Synthetic Rubber Co., Ltd. 10
Weight part of Butyl recycled rubber manufactured by Hayakawa Rubber
A total of 62 parts by weight of 2 parts by weight is kneaded for about 20 minutes in an about 12,000 pressure kneader and passed between about 120 oo rolls to obtain a rubber sheet with a desired thickness.

Example 6 Tire Calo Sulfur Rubber Powder 20-40 mesh 50 parts by weight RB#820 manufactured by Japan Synthetic Rubber ■ 1
0 parts by weight Made by Japan Synthetic Rubber 11R#665
A total of 61 parts by weight of 1 part by weight was kneaded in a pressure kneader at about 1200C to give about 120 parts by weight.
℃ to obtain a rubber sheet of desired thickness.

Example 7 Tire vulcanized rubber powder 20-40 mesh 30 parts by weight RB#820 manufactured by Japan Synthetic Rubber 1
0 parts by weight Japanese synthetic rubber is Mura 11R#065
2 parts by weight (total of 42 parts by weight) were kneaded for about 15 minutes in a pressure kneader at about 110oC to give about 1
A rubber sheet of desired thickness is obtained by passing between rolls at 10°C.

The physical properties of the rubber compositions according to Examples 1 to 7 are shown in Table 1.

Comparative Example 1 Tire vulcanized rubber powder 40 to 60 mesh 40 parts by weight Ethylene-acetyl-pine copolymer 10 parts by weight (corrosion content 28%, skin 15) Total 50 parts by weight were pressurized at about 110oo Knead with a kneader for about 15 minutes, about 1
When passed between rolls at 00°C, it sticks to the rolls, and even if stearic acid is added as an external detergent, it tends to stick to the rolls even if the roll temperature is lowered, and furthermore, even if it leaves the rolls, the cohesive force at the time of heat is low. It is weak and difficult to obtain a rubber sheet with the desired shape.

Comparative Example 2 When tire vulcanized rubber powder is kneaded with PVC and plasticizer DOP, mixing is difficult at 150 qo or less.
There is no strength.

Comparative Example 3 10 parts by weight of natural rubber and 10 parts by weight of vulcanized rubber powder were kneaded in a pressure kneader.

Even when passed between rolls, it does not become like a rubber sheet, regardless of the roll temperature. Examples and comparative examples using only the roll rolling method have been shown above, but even if the mixture is kneaded using a pressure kneader and then extruded using an extruder, or compression molded using a compression molding machine, the injection molding machine Even when injection molded, it has higher elasticity than other materials.
It is possible to obtain a rubber composition that is flexible, hard to wear, and has a light specific gravity.

Table 1

Claims (1)

[Claims] 1 100 parts by weight of fluidized rubber powder and 10 to 100 parts by weight of polybutadiene resin or butadiene-styrene block polymer
A non-crosslinkable compound having elasticity, strength, and flexibility, consisting of a compound made by uniformly kneading 1 to 20 parts by weight of one or more of polyisobutylene rubber, butyl rubber, chloroprene rubber, and butyl recycled rubber. Rubber composition.