JPS5918746A - Manufacture of rubber product having improved oil resistance - Google Patents

Abstract

PURPOSE:To obtain a rubber product having improved oil resistance, by adding a polymerization initiator again to an amorphous copolymer composed of ethylene, an alpha-olefin, and optionally a non-conjugated diolefin, and subjecting the mixture to a high-temperature dynamic treatment under high temperature and shearing force. CONSTITUTION:An amorphous copolymer composed of ethylene, alpha-olefin (especially propylene) and optionally a non-conjugated diolefin, is mixed with a polymerization initiator, e.g. a radical generator or a compound having active group, e.g. peroxides, oxime, etc., at <=100 deg.C. The mixture is then subjected to the high-temperature dynamic treatment at a temperature of as high as >=100 deg.C (150-250 deg.C) under shearing force to generate the xylene-insoluble component in an amount of 50-70wt%.

Description

[Detailed description of the invention] A copolymer of ethylene and α-olefin, or a non-conjugated diolefin (hereinafter simply referred to as ethylene propylene rubber, because propylene is the most representative and important olefin) (sodium hydroxide, potassium hydroxide, hydrochloric acid, sulfuric acid, sulfur chloride) Inorganic alkalis, inorganic acids, inorganic salts in aqueous solutions of IJium, as well as highly polar compounds with 1 to 5 carbon atoms such as methanol, ethanol, ethylene glycol, and acetone. Excellent chemical resistance to organic solutions,
Rubber plates, sealants, backings, etc. that come into contact with these chemicals,
Used for tank linings, etc.

However, it swells violently in nonpolar organic solutions such as carbon tetrachloride, toluene, hexane, gasoline, grease, and various mineral oils, and it is not possible to manufacture rubber products that come into contact with these solutions using ethylene propylene rubber alone. Since these non-polar organic solutions are typified by so-called "oils," ethylene propylene rubber is widely and generally expressed as having poor oil resistance.

Rubbers with good oil resistance include chloroprene rubber and acrylonitrile butadiene rubber, but these rubbers are inferior to ethylene propylene rubber in heat resistance and weather resistance.

Therefore, blend rubber products are manufactured that balance the heat resistance, weather resistance, ozone resistance, etc. of ethylene propylene rubber with the oil resistance of chloroprene rubber, acrylonitrile butadiene rubber, etc. As the blend ratio of ethylene propylene rubber to the latter increases, heat resistance, weather resistance, ozone resistance, etc. improve, but oil resistance decreases accordingly, so its use 51 has to be restricted.

Therefore, we would like to improve the oil resistance of ethylene propylene comb.
1- is a very important issue.

The present inventors have worked to solve this difficult problem and have arrived at the present invention.

The present invention improves the oil resistance of ethylene propylene rubber by producing xylene-insoluble components in ethylene propylene rubber under special conditions of high temperatures of 100°C or higher and in the presence of shearing force.

In the present invention, a polymerization agent is used to generate xylene-insoluble components, but it is important to note that
゛The mixture acts on ethylene and propylene (and non-conjugated diolefin) to form xylene-insoluble components.
This is not the stage where ethylene propylene rubber is polymerized. In the present invention, a polymerizing agent is added to ethylene propylene rubber as a polymer that has already been polymerized to generate xylene-insoluble components at high temperature and in the presence of shearing force.

The method for producing the xylene-insoluble component will be described below.

What does this invention mean? J< Mixtures are compounds with radical generators such as peroxides, oximes, and sulfur, and active groups (e.g., unsaturated double bonds), which generate three-dimensional bonds in ethylene propylene comb, and A compound that can be incorporated into an original bond. Furthermore, a polymerization aid (these are known as crosslinking aids and vulcanization accelerators for ethylene propylene rubber) can be used in combination. The type, amount, etc. of these polymerization agents and polymerization aids are determined by the conditions for producing xylene-insoluble components (temperature, polymerization time, etc.), and the most common polymerization agent is peroxide. These polymerization agents and polymerization aids are generally mixed using an open roll or the like at a low temperature of 100° C. or lower, at which no polymerization occurs. Sometimes, ethylene propylene rubber is placed at high temperature and under shearing force before mixing.

In rare cases, for example, a polymerizing agent and an auxiliary agent are added to a solution containing ethylene propylene rubber such as toluene or hexane, and then the solvent is removed and the ethylene/propylene rubber containing the polymerizing agent and auxiliary agent is prepared. Sometimes you can get it.

Ethylene propylene rubber containing such a polymerization agent has a 100%
High temperature above ℃ (generally 150 to 250℃) and shearing IM
In the presence of an ionic force, the formation of xylene-insoluble components takes place. At this time, it is common to use a device having a closed or semi-closed chamber, such as a Banbury or a kneader, and the inside of the chamber may be replaced with nitrogen.

The xylene-insoluble component referred to in the present invention is obtained by using 300 m/g of xylene per 0.5 P of ethylene propylene rubber, dissolving it at the boiling point for 3 hours, filtering it through a 120-mesh wire mesh, and drying and weighing the residue, which has a weight of 5 to 70 kg. ffi% range. After a predetermined xylene-insoluble component mother is polymerized, the polymerization is stopped using a polymerization terminator having a radical scavenging action or by rapidly cooling the polymerization to a temperature below the polymerization temperature.

As can be seen from the above, it must be noted that in the present invention, the xylene-insoluble component is generated under dynamic conditions of shear force.

Furthermore, in the past, xylene-insoluble components (in this case, those produced during the polymerization stage of ethylene propylene rubber) were considered undesirable as they remained as foreign matter in rubber products and caused deterioration of physical properties. It should be noted that in the present invention, a xylene-insoluble component is intentionally produced as a preferable component.

Through such high-temperature dynamic treatment, the ethylene propylene rubber containing a predetermined amount of xylene-insoluble components is processed using a roll or banbury, etc., and is treated with other rubbers such as ethylene propylene rubber, acrylonitrile butadiene rubber, carbon black, white, etc. as necessary. Fillers, vulcanizing agents, vulcanization accelerators, anti-aging agents, processing aids, etc. are blended and vulcanization is performed. Rubber products using ethylene propylene rubber with improved oil resistance include rubber plates, backings, Sealants, etc. are manufactured.

Examples will be shown below, but the present invention is not limited thereto.

Example 1 An example is described which shows that the chemical resistance of ethylene propyl non-rubber is improved by using the present invention.

(High-temperature dynamic treatment of ethylene propylene rubber) Mooney viscosity (ML 100°C) -45.1+4 Dicumyl peroxide was added to 100 parts by weight of ENB type ethylene propylene rubber with a propylene content of 45% by weight and an iodine value of 12 as a polymerization agent for xylene-insoluble components. No-id O
A portion of 07 heavy eggplant was added using a low temperature roll at 50°C. Next, using a BR type Banbury, the xylene-insoluble components were polymerized at 190-200°C and a rotor rotation speed of 12P for 10 minutes at high temperature and in the presence of shearing force, and then 1 part by weight of dilauryl thiodipropionate was polymerized. was added and held in the presence of high-temperature shearing force for another 2 minutes to stop polymerization, thereby obtaining the desired high-temperature dynamically treated ethylene propylene rubber. The obtained ethylene propylene rubber had a xylene-insoluble component of 53 units.

(Composition) Ethylene propylene rubber 1oo (1 part) F E
F carbon black 100 naphthene oil
70 Zinc Flower 5 Stearic acid
1 Tsukushinol BZ 2TT
Q@5 TRA O,5 λ(1 I O
1゜5 (kneading) BR type Banbury, 70℃ Star j, 12P mastication 3
0'', mixed wire 4'30'' Total 5 minutes kneading (vulcanization) (Results) Change in volume (Relationship) Example 2 The oil resistance of ethylene propylene rubbers with different xylene-insoluble components (■) is shown.

(Test method, etc.) Same as Example 1. However, ENB type ethylene propylene rubber with an iodine value of 24 was used, and ethylene propylene rubber with various amounts of xylene insoluble components adjusted by adding dicumyl peroxide was used. It is shown below that the oil resistance is improved only in ethylene propylene rubber by polymerizing a large amount of xylene-insoluble components.

Example 3 The results of a study on a blend of acrylonitrile butadiene rubber and ethylene propylene rubber are shown.

(Composition) Ethylene propylene rubber 50 (3ffiff
1 part) Acrylonitrile butadiene rubber 50H
A F carbon black 50 Naphthenic oil 10 Zinc white 5 Stearic acid 1 Tsuxinol cz 2 Io
C 1°5 (other conditions) Same as Example 2. However, as a polymerization agent, 1゜3bis(tert-butylperoxyisopropyl)benzene 0.5
The xylene-insoluble component was polymerized at 200 to 205°C using parts by weight.

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Claims (1)

[Claims] A polymerizing agent is added to an amorphous copolymer consisting of ethylene and olefin or these and a non-conjugated diolefin, and 100%
A rubber product with excellent oil resistance by using an amorphous copolymer characterized by the formation of xylene-insoluble components of 5 to 70M by dynamic treatment at high temperatures above ℃ and in the presence of shearing force. How to manufacture.