JPS604542A - Halogen-containing rubber composition - Google Patents

Abstract

PURPOSE:To provide a composition which can be vulcanized with sulfur, by compounding a halogenated EPM or halogenated EPDM with sulfur, calcium oxide as an acid acceptor, and a vulcanization accelerator. CONSTITUTION:The objective composition can be produced by compounding (A) 100pts.wt. of a halogen-containing ethylene/alpha-olefin copolymer or a halogen-containing ethylene/alpha-olefin/non-conjugated diene copolymer with (B) 1-50pts.wt. of calcium oxide, (C) 0.1-5.0pts.wt. each of dithiocarbamic acid salts, thiurams, thiazoles and/or guanidines as vulcanization accelerator, and (D) 0.2-10pts.wt. of sulfur. The composition may be compounded further with 1-50pts.wt. of oxide of magnesium, lead or antimony, or 0.5-30pts.wt. of zinc stearate. The alpha-olefin in the component A is propylene and the halogen-content is 1-50wt%, preferably 3-40wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides sulfur vulcanizable halogen-containing ethylene-α
Olefin copolymer, halogen-containing ethylene-α-olefin-nonconjugated diene copolymer (hereinafter propylene is the most representative α-olefin, so halogenated EP
M, abbreviated as halogenated EPDM) rubber composition. EPM and EPDM have excellent heat resistance, weather resistance, ozone resistance, etc., and are used in a wide range of applications. However, since there are no polar groups in the polymer structure, it is oil resistant and
It has a major drawback of poor organic solvent resistance. Therefore, for hoses, belts, and backing applications that require oil resistance, a method (blend) of using oil-resistant rubbers such as acrylonitrile butadiene rubber (NBR) and chloroprene rubber (3R), which have excellent oil resistance, has been used. However, it involves problems such as poor co-vulcanization and non-uniform dispersion of fillers, vulcanization accelerators, etc.).

On the other hand, many attempts have been made to improve oil resistance by introducing polar groups into EPM and EPDM. The most typical example is the introduction of halogen, and halogenated EPDM is widely known. However, halogenated EPI)M is actually only used in limited applications as some adhesives. The reason for this was that there was no technology that enabled sulfur vulcanization.

The most typical methods for crosslinking rubber are sulfur vulcanization and peroxide vulcanization, and sulfur vulcanization in particular allows for the crosslinking rate to be greatly adjusted by selecting and varying the vulcanization accelerator; However, it has the major feature that crosslinking progresses, and is used in a much wider range than peroxide vulcanization. Of course, some types of rubber can only be peroxide vulcanized, but many general-purpose rubbers, such as natural rubber, styrene-butadiene rubber (SBR),
For EPDM and NBR, sulfur vulcanization is much more common than peroxide vulcanization.

The present inventors have studied methods for vulcanizing halogenated EPM and halogenated EPDM in order to make this sulfur vulcanization possible, and have arrived at the present invention.

The present invention relates to a sulfur-curable rubber composition using halogenated EPM or halogenated EPDM,
It goes without saying that it contains sulfur as a crosslinking agent, but it also contains a limited amount of acid acceptor and a limited amount of vulcanization accelerator for efficient crosslinking.

In order to vulcanize halogenated EPM, halogenated EPDMlz sulfur, it is necessary to cause a dehalogenation reaction in a high temperature range (below the vulcanization temperature) where crosslinking occurs, but at this time acidic substances such as hydrochloric acid are released. For this purpose, an acid acceptor is required, and the present inventors have made sulfur vulcanization possible by selecting a limited compound, calcium oxide, as the acid acceptor.

As acid acceptors for halogenated polymers such as OR and chlorinated polyethylene, metal oxides such as magnesium and lead, hydroxides of these metals, and the like are widely known. Although calcium hydroxide and calcium oxide are also known,
Halogenated polymers such as R and chlorinated polyethylene have extremely low acid-accepting effects compared to the metal compounds mentioned above, and therefore have almost never been put to practical use.

The present inventors have discovered that halogenated EPM, halogenated EPDM
As a result of intensive studies on the sulfur vulcanization method, it was discovered that calcium oxide, which was conventionally thought to have very little effect, has an extremely excellent effect on these polymers.

This is truly surprising. Of course, conventional acid acceptors such as lead monoxide and magnesium oxide can be used in combination with calcium oxide, but sufficient crosslinking cannot be achieved in the absence of calcium oxide, and the properties are insufficient. That is, the composition of the present invention requires calcium oxide.

The composition of the present invention thus contains calcium oxide, but the amount is equal to that of halogenated EPM.

The amount is 1 to 50 parts by weight, preferably 2 to 80 parts by weight per 100 parts by weight of halogenated EPDM. If the amount is less than this, a sufficient effect will not be obtained, and even if the amount is increased beyond this, no effect will be seen. In addition, the amount of metal oxides such as magnesium and lead used as auxiliary acid acceptors is 1 to 5.
0 parts by weight, generally 2 to 80 parts by weight.

Furthermore, the present inventors used as a vulcanization accelerator one or more selected from the groups i) to: 11): j) dithiocarbamates, II) thiurams, 111) thiazoles and/or guanidines; It has been discovered that it is important to use two or more types of accelerators in combination. In other words, the present inventor believes that sulfur vulcanization of halogenated EP'M and halogenated EPDM can only be achieved practically satisfactorily by the combination of a specific acid acceptor and a specific vulcanization system. found that it is not possible to obtain practically satisfactory physical properties with dithiocarbamates alone, thiurams alone, thiazoles alone, or guanidine alone.As dithiocarbamates, zinc dimethyldithiocarbamate and diethyldithiocarbamine Zinc acid, zinc di-11-butyldithiocarbamate, tellurium diethyldithiocarbamate, etc.; examples of thiurams include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, tetraethylthiuram disulfide, and tetrabutylthiuram disulfide. etc., but
Thiazoles include 2-mercaptobenzothiazole, dibenzothiazyl disulfide, 2-mercaptobenzothiazole zinc salt, N-cyclohexyl-2-benzothiazole sulfenamide, N-oxyethylene-
Examples of the guanidines include 2-benzothiazole and the like, and examples of the guanidines include diphenylguanidine and di-orthotolylguanidine. Accelerator i, t O, selected from each group
1-5. ．． Omi part, general +in +, t 0.2~8
．． It is used in an amount of 0 parts by weight. If necessary, 0.5 to 30 parts of zinc stearate, which has an active effect, is added.

In the present invention, halogenated EPM, halogenated E
PDM contains halogens such as chlorine, bromine, and fluorine, but it generally contains chlorine or both chlorine and bromine. The content of these halogens is 1 to 50% by weight, preferably 3 to 40% by weight.
It has been adjusted so that These halogenated polymers can be produced using a solution method in which halogen is introduced into a carbon tetrachloride solution of EPM or EPDM, a gas phase method in which halogenation is carried out in the gas phase without using a medium, and an aqueous suspension method in which halogen is introduced by suspending it in water. etc., which can be obtained by known methods.

The composition of the present invention is a composition using a halogen-containing ethylene-α-olefin copolymer and a halogen-containing ethylene-α-olefin-nonconjugated diene copolymer, but propylene is the most representative and important α-olefin. For this reason, as mentioned above, in this specification, propylene is representative of α-olefin.

As a non-conjugated diene, ethylidene norbornene (END
), dicyclopentadiene (DCFD), 1,4-hexadiene (1,4-HD), and the like.

The composition of the present invention contains various carbon blacks, white fillers, process oils, processing aids, anti-aging agents, pigments, etc. selected as necessary, but the content is determined depending on the required physical properties and the like. Determined empirically considering low characteristics.

The present composition can be obtained using a kneader such as a Banbury, Nigu, or Roll kneader. In addition, vulcanization can be done using presses, vulcanizing cans,
This process is achieved using injection and various types of continuous vulcanization equipment, making it possible to obtain various rubber products such as hoses, backings, belts, linings, and gaskets with excellent oil resistance and organic solvent resistance.

Examples will be described below, but they do not limit the present invention.

4. Examples 1 to 7, Comparative Examples 1 to 4 Ethylene-propylene-ethylidene norbornene terpolymer EPDM (Mooney viscosity MLl+ 4100°C
-45, Iodination = 12, Ethylene content = 55 w
t%) based on chlorine content 15wt%, 25w
t% of chlorinated EPDM was roll-kneaded according to the recipe shown in Table 1, and press vulcanization was performed at 160°C for 60 minutes to obtain a vulcanized rubber test piece. The physical properties were measured in accordance with JI8/6301.

Table 2 shows the results of the tensile test and hardness test, and Table 3 shows the results of the oil resistance test. If the sulfur accelerator is a dithiocarbamate alone, a thiuram alone, or a thiazole alone, sufficient physical properties cannot be obtained in any of the formulations.

Continuation of page 1 0 shots Akira Masato Ogura 5-1 Sokai-cho, Niihama City Sumitomo Chemical Within Gakkogyo Co., Ltd. 0 shots: Masahiro Niwano 5-1 Sokai-cho, Niihama City Sumitomo Chemical Within Gakkogyo Co., Ltd.

Claims (1)

[Scope of Claims] 1) Adding 100 parts by weight of these copolymers to a halogen-containing ethylene-α-olefin copolymer or a halogen-containing ethylene-α-olefin-nonconjugated diene copolymer.
0 parts by weight of calcium oxide; 0.1 as vulcanization accelerator
~5.0 parts by weight of dithiocarbamates, 0.1-5
．． 0 parts by weight of thiurams, 0.1 to 5.0 parts by weight of thiazoles and/or guanidines; and 0.2 parts by weight
A sulfur-vulcanizable halogen-containing rubber composition, characterized in that it contains ~1000 parts by weight of sulfur. 2) Magnesium, lead, antimony oxides from 1 to 50
The halogen-containing rubber composition according to claim 1, containing parts by weight. 8) The halogen-containing rubber composition according to claim 1 or 2, which contains 0.5 to 80 parts by weight of zinc stearate.