JPS60229940A - Rubber composition - Google Patents

Abstract

PURPOSE:A composition, obtained by incorporating ethylene-propylene based rubber with a thermoplastic olefinic polymer and specific furnace carbon black, and having a low specific gravity and improved roll and extrusion moldability. CONSTITUTION:A composition obtained by incorporating 100pts.wt. ethylene propylene based rubber with 10-50pts.wt., preferably 15-45pts.wt. thermoplastic olefinic polymer, preferably polypropylene and furnace carbon black having 40- 80mg/g iodine absorption and >=140ml/100g oil absorption of dibutyl phthalate. The amount of the carbon black to be incorporated is preferably 20-300pts.wt., based on 100pts.wt. total amount of the ethylene propylene based rubber and the olefinic polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Go18 composition with low specific gravity and excellent roll and extrudability. More specifically, a low specific gravity furnace carbon blank made of ethylene di-1-l pyrene rubber, a thermoplastic olefin polymer, an iodine adsorption amount of 40 to 80 mg/g, and a dibdelphthalate oil absorption of 140 m x /100 g or more is used in rolls and The present invention relates to a rubber composition with improved extrusion moldability.

Conventionally, many rubber products have been used in automobiles, and among these, ethylene propylene rubber, which has good weather resistance and ozone resistance, is used as a material for parts that are directly exposed to light and the atmosphere. . In recent years, improving the fuel efficiency of automobiles has become an important issue, and as a result, it has become necessary to make automobiles lighter, and in response, there has been a strong demand for lighter weight rubber products.

Conventionally, rubber products are manufactured by vulcanizing rubber by blending it with carbon blank and other white pigments, softening agents, vulcanizing agents, etc. Ethylene propylene rubber has a low specific gravity of about 0.86 among rubbers, so it is advantageous for weight reduction, but it is not suitable for carbon blanks (specific gravity of about 1.8) and other fillers (specific gravity of about 2.5). By blending
ζCurrently, the specific gravity of the final product is approximately 1.3. Rubber products are required to have a certain degree of hardness in order to impart strength or rigidity, and to achieve this, it is common practice to adjust the blending amounts of carbon blank and softener. That is, if a carbon blank is blended, the hardness will increase, and if a softener (specific gravity around 0.9) is blended, the hardness will be decreased.

For rubber products using ethylene propylene rubber, the specific gravity can be reduced by reducing the amount of carbon blank blended, but it is necessary to also reduce the amount of softener blended in order to obtain the desired hardness. Therefore, it is inevitable to use a low-filling formulation with a small total amount.

Ethylene propylene rubber cannot be used industrially due to 1) poor processability and extrusion processability with such low filling formulations.

= On the other hand, it is known to blend polypropylene or polyethylene with 1-1 ethylene-1 pyrene rubber, and by blending, paulownia wood with low specific gravity and constant hardness can be obtained. However, in the case of a blend of ethylene propylene thread rubber and polypropylene or polyethylene,
It has the disadvantages of low strength such as tensile strength and tearability, and poor roll processability and extrusion processability.

In view of these points, the inventors have conducted extensive research and found that
1 g of ethylene! For pyrene rubber and thermoplastic olefin polymer, iodine adsorption amount 40 to 80 /g, dibutyl phthalate 1-suction If 140 m e / 100
By blending more than g of furnace carbon silk,! The inventors have discovered that it is possible to produce a comb composition with a low specific gravity that has good properties.

Of course, the present invention is based on ethylene propylene rubber 100.
Provided is a rubber composition comprising 10 to 50 parts by weight of a thermal 11J plastic olefin polymer, a furnace carbon black having an iodine adsorption amount of 40 to 80 μ/g, and a dibutyl phthalate oil absorption amount of 140 ml/100 g or more.

Examples of the above ethylene propylene rubber include
Ethylene-propylene-nonconjugated diene copolymer rubber containing one or more of the following as a non-conjugated diene: ethylene-propylene copolymer rubber, ethylidene norbornene, cyclopentadiene, 1,4-hexadiene, methylenenorbornene loindene etc.

The thermoplastic olefin polymer is an amorphous or crystalline C7-C8α-monoolefin homopolymer or copolymer, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 2 -methyl-1-
Propene, 3-methyl-1-pentene, 4-methyl-1
-pentene, 5-methyl-1-hexene and mixtures thereof. Among these, polypropylene is particularly preferred.

What about the above furnace carbon sill? i element adsorption amount 40~
80■/g, dibutyl phthalate oil absorption 140m (1
/ A special furnace carbon blank weighing over 100g.

If the iodine adsorption amount is less than 40 mg/g,
If it is not possible to obtain sufficient hardness and strength for the vulcanized rubber, and if it is larger than 80μ/g, the particle size will become fine.
Because the coagulation force between carbon black particles is large, the dispersibility in rubber (! l (If it is smaller than 10 g, the iodine adsorption Mf is large, the ti & property or F is low, and the small iodine adsorption Mf is not improved by 1'.

In order to obtain the effects of the present invention, the compounding amount of the car pump hook of the present invention is as follows.
20 to -300 i'nM parts with respect to the vehicle volume part is preferable. 20 Shiyobe C/β:1 is insufficient in hardness and strength,
Workability deteriorates. Furthermore, if the weight exceeds 300 parts, processability deteriorates and tensile properties tend to decrease.

The amount of the thermoplastic olefin polymer is 10 to 50 parts by weight, preferably 15 to 45 parts by weight, based on 100 parts by weight of the ethylene propylene rubber. Less than 10 parts by weight,
If the amount exceeds 50j;ff parts, the rubber-like elasticity will be poor and the roll processability will be poor.

That is, ethylene thread rubber: J-pyrene rubber, blending JL with plastic olefin mixture, and iodine adsorption amount of 40 to 80 mg/g-dibutyl phthalate oil absorption amount of 1
It is known that a furnace carbon black of 40 m n /100 or more can be blended with ethylene propylene rubber, but it is not possible to combine p% ++J plastic olefin polymer and the above carbon black into ethylene propylene rubber, which is expected from known technology. It was discovered that excellent workability and strength could be obtained that could not be achieved with other materials, and this led to the present invention.

The rubber composition of the present invention can contain conventional rubber compounding agents, such as softeners, process oil anti-aging agents, vulcanization accelerators, vulcanizing agents, and blowing agents.

A preferred blending ratio of the carbon blank and the softener or process oil used in the present invention is carbon black/softener=2/1 to 1/2 (weight ratio).

There are no particular restrictions on the method of mixing the rubber composition of the present invention, and all the ingredients may be mixed simultaneously using a roll, Banbury mixer, etc., or the ethylene propylene rubber and thermoplastic olefin polymer may be blended in advance.
This blend may be used to mix other formulations.

The rubber composition of the present invention can be molded and vulcanized using ordinary vulcanized rubber manufacturing equipment and manufacturing conditions.

The rubber composition of the present invention has good processability, low specific gravity, and high strength such as tensile strength and tearability, so it can be used for window frames,
Various hoses, various sealing materials, sponges, electrical insulation materials
It is good luck to use for 1.

Next, the present invention will be explained in detail by way of Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded. As mentioned above, "Part J" is based on the weight standard.

Examples 1 to 4, Comparative Examples 1 to 3 According to the compounding recipe shown in Table 1, the mixture was kneaded using a two-mill mill to obtain 1M unvulcanized compounded rubber. The obtained λ: compounded rubber was press-vulcanized at 160°C for 15 minutes. The obtained vulcanizate G was cracked and subjected to a tensile test and a tear test according to JIS K2SO3. The evaluation results are shown in Table-2.

In addition, the extrusion property values in the table are the values measured using the Garhei die described in ASTM 02230 at a cylinder temperature of 80°C, a temperature of 100'C, and a rotational speed of 30γPm, and are expressed in accordance with STM 02330. .

As is clear from Table 2, the rubber composition of the present invention has 1
': It can be seen that the material has good properties when rolled, good extrusion workability, low specific gravity, and high tensile strength and tear strength.

1 The iodine adsorption amount and the sobutylphthale-1 oil absorption amount of the carbon blanks shown in Table I were determined by the following method.

hl phosphorus adsorption N (mg/g): JIS K62
The iodine adsorption (mg) per 1 g of drying capacity bomb was calculated based on 21.

Dibutyl phthalate oil absorption: , US K6221 [
The oil absorption amount (mβ) of dibutyl phthalate per 100 g of dry carphone was calculated based on Method A (mechanical method) 1.

Claims (2)

[Claims] (1) 100 parts by weight of cochilene propylene rubber, 10 to 50 parts by weight of thermoplastic olefin polymer, iodine adsorption amount of 40 to 80 μ/g, dibutyl phthalate oil absorption amount of 14
0m 1/100g or less furnace carbon fiber. A rubber composition consisting of (2) The rubber composition according to claim 1, wherein the thermoplastic olefin polymer is polypropylene.