JPS62177063A - Epichlorohydrin-propylene oxide based rubber composition - Google Patents

Abstract

PURPOSE:A rubber composition, obtained by blending epichlorohydrin-propylene oxide based rubber with a specific silicon compound and a crosslinking agent consisting of a heterocyclic ring-containing polythiol (derivative) and having improved heat aging resistance. CONSTITUTION:A composition obtained by blending (A) 100pts.wt. copolymer rubber or rubber mixture containing 10-90mol% epichlorohydrin, 10-90mol% prypylene oxide, 0-60mol% ethylene oxide and 0-15mol% allyl glycidyl ether with (B) 10-90pts.wt. one or more silicon compounds selected from hydrous silicic acid, calcium silicate and magnesium silicate and (C) 0.1-8pts.wt. crosslinking agent consisting of a heterocyclic ring-containing polythiol (derivative), e.g. dimercaptopyrazine (derivative), etc. If 0.1-5pts.wt. silane coupling agent is further blended, more improved physical properties of crosslinked material and heat aging characteristic are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) -1 The present invention relates to an epichlorohydrin-propylene oxide rubber composition, and particularly to a rubber composition with excellent heat aging resistance.

(Prior Art) Propylene oxide copolymer rubber is known to be a rubber material with well-balanced properties such as oil resistance, ozone resistance, and cold resistance. However, it cannot be said that they are necessarily excellent in heat aging resistance, and at present they have not been widely used industrially.

(Objective of the Invention) The object of the present invention is to provide an epichlorohydrocane-propylene oxide rubber composition which not only has the properties previously possessed but also has heat aging resistance, which has been a drawback in the past. .

(Structure of the Invention) The present invention is characterized in that (a) the constituent units of the copolymer rubber or rubber mixture are 10 to 90 mol % of epichlorhydride.

(b) 10 to 90 parts by weight of one or more silicon compounds selected from hydrous silicic acid, calcium silicate, and magnesium silicate, per 100 parts by weight of propylene oxide 10 to 90 mol%, ethylene oxide 60% by weight and (c) a crosslinking agent made of a heterocyclic borodiol or a derivative thereof.
This is a shrimp chlorohydrin-propylene oxide based rubber composition characterized by containing 1 to 8 parts by weight.

In the present invention, the copolymer rubber or rubber mixture which is component (a>
0 mol%, preferably 20-80 mol%.

10-90 mol% propylene oxide, preferably 2
0 to 80 mol%, ethylene oxide 0 to 60 mol%,
Preferably a copolymer rubber or rubber mixture is used in the range 0 to 40 mol %, allyl glycidyl ether 0 to 15 mol %, preferably 0 to 10 mol %.

Examples of the above copolymer rubber include shrimp chlorohydrin-
Propylene oxide binary copolymer, epichlorohydrin-propylene oxide-ethylene A kyrieite terpolymer, shrimp chlorohydrin-propylene oxide-aval glycidyl ether terpolymer, epichlorohydrin-propylene oxide-ethylene oxide-allyl glycidyl Examples include ether quaternary copolymers.

Examples of rubber mixtures include copolymer rubbers consisting of the above components, as well as epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, shrimp chlorohydrin-allyl glycidyl ether binary copolymer, Rubber made of epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer is appropriately mixed and used so that the mole % of each of the above-mentioned constituent units is controlled. In these rubbers for mixing, in the case of a binary copolymer, in the case of an epichlorohydrin-propylene oxide copolymer, the former constituent unit is 5 to 95 mol%, preferably 10 to 90 mol%; In the can-ethylene oxide copolymer, the former structural unit is 5 to 95 mol%, preferably 10 to 90 mol%,
In the shrimp chlorhydrocane-allyl glycidyl ether copolymer, the latter structural unit may be present in an amount of 15 mol% or less, preferably 10 mol% or less. In the case of terpolymer,
For epichlorohydrin-propylene oxide-ethylene oxide copolymer, epichlorohydrin 10-9
0 mol%, preferably 20-80 mol%, propylene oxide 5-80 mol%, preferably 10-70 mol%
, 5 to 80 mol% of ethylene oxide, preferably 10
~70 mol% of shrimp chlorohydrin-propylene oxide-allyl glycidyl ether copolymer,
Epichlorohydrin 5-90 mol%, preferably 10-90 mol%
80 mol%, propylene oxide 5 to 90 mol%, preferably 10 to 80 mol%, allyl glycidyl ether 15 mol%, preferably 10 mol% or less.

In the case of a quaternary copolymer, those having the mole % range of each structural unit specified in the present invention are used.

In the composition ratio of each constituent unit of the copolymer rubber or mixture used in the present invention, if shrimp chlorohydrin is less than 10 mol%, the vulcanization rate and oil resistance will decrease;
If it exceeds 0 mol %, cold resistance decreases, which is not preferable. If the propylene oxide content is less than 10 mol%, the cold resistance will decrease, and if it exceeds 90 mol%, the oil resistance will decrease. Ethylene oxide is introduced for the same purpose as propylene oxide, but if it exceeds 60 mol%, the solubility of additives such as plasticizers and anti-aging agents that are optionally added to the composition decreases, causing the blooming phenomenon. This is not desirable because it causes

Allyl glycidyl ether is introduced in order to maintain especially excellent ozone resistance, but if it exceeds 15 mol %, the oil resistance will deteriorate and the tendency for embrittlement after heat aging will become significant, which is not preferable.

The silicon compound as component (b) used in the present invention consists of one or a mixture of two or more selected from hydrous silicic acid, calcium silicate, and magnesium silicate, and these are those commonly used in the rubber industry. It can be applied as is. The blending amount is in the range of 10 to 90 parts by weight, preferably 20 to 70 parts by weight, based on 100 parts by weight of the copolymer rubber or rubber mixture.

If the amount is less than 10 parts by weight, it is difficult to obtain sufficient mechanical properties, and if it exceeds 90 parts by weight, the crosslinking rate will decrease and the rubber flexibility of the vulcanizate will be impaired. Undesirable.

The crosslinking agent consisting of heterocyclic polythiols or derivatives thereof, which is the component (c) used in the present invention, is generally known as Dimerkab 1 to pyrazines or derivatives thereof (Japanese Patent Publication No. 58-14468 Publications), Shimercap 1 to Quinoxalines or Derivatives thereof (Special Publications 1987-14)
．． 469), dimercapto 1 to lyazoles or derivatives thereof (Japanese Patent Publication No. 57-46463), dithiohydantoins or derivatives thereof (Japanese Patent Publication No. 58-14.4)
．． 67@ Publication, JP-A No. 57-34.160, JP-A-57-126854), trithiocyanuric acid or its derivatives (Japanese Patent Publication No. 48-36926), dimercaptothiadiazole or its derivatives (Japanese Patent Publication No. 48-36926), Kosho 53
-3439). Specific examples of these include 2,3-dimercap 1-pyrazine, 6-methylquinoxaline-2,3-dithiocarbonate, 3,
5-dimercapto-1-phenyl-1,2,4-triazole, 5,5-dimethyl-2,4-dithiohydantoin, trithiocyanuric acid, 6-cyptylamino-2,
Examples include 4-dimercapto-5-1 to riazine.

The blending amount should be in the range of 0.1 to 8 parts by weight, preferably 0.3 to 6 parts by weight, based on 100 parts by weight of the copolymer rubber or rubber mixture. If the amount is less than 0.1 part by weight, a sufficient degree of crosslinking will not be obtained, and if it exceeds 8 parts by weight, the rubber elasticity will decrease, which is not preferable.

The composition of the present invention has excellent heat aging resistance, which is the object of the present invention, even when using thioureas and polyamines, such as ethylene thiourea and hexamethylene diamine carbamate, which are known as the most common crosslinking agents for this type of rubber. cannot be obtained. On the other hand, if carbon black, which is known as the most common reinforcing agent, is used instead of the silicon compound of the present invention, the same object as the present invention cannot be achieved even if the crosslinking agent of the present invention is used.

In order to obtain even better crosslinking properties and heat aging resistance in the composition of the present invention, it is highly preferable to use silane coupling agents represented by the following general formulas (I) to (X).

CJIC3Hs 5i(OR)3
(I) H3O3H65i (OR) 3
(III) H2O2H45i(OR)3
(IV>H2NC2H4NHC3H65i
(OR) 3 (■) H3 H2NC3Hs 5i (OR) 2 (I
X) NH2C0NI-IO2H65i (OR>3
(X) (However, in the above general formulas (1) to (X), R represents a methyl group or an ethyl group) When using the silane coupling agent of the above general formulas (I) to (X), the type thereof It was found that although cross-linked Q has almost no effect on the physical properties, there are some points that should be taken into account when handling uncross-linked compounds. That is, the above general formula (■).

(■v) and he (■■) ~ (X), especially (III),
(IV) has some difficulty in viscosity stability when storing uncrosslinked formulations, and although there is no problem in normal handling, adverse effects appear especially when stored in a hot and humid environment. We found that special care should be taken when handling in such an environment. On the other hand, it has been found that (I), (ff>, (V) and (Vl) are very effective additives in practice, as their viscosity stability is hardly inhibited even under such environments.

The amount of the silane coupling agent blended is in the range of 0.1 to 5 parts by weight, particularly preferably 0.2 to 3 parts by weight, per 100 parts by weight of the copolymer rubber or rubber mixture.

If the blending amount is less than 0.1 part by weight, the desired effects of the present invention cannot be sufficiently achieved. Moreover, even if the blending amount exceeds 5 parts by weight, a substantial effect corresponding to the blending amount cannot be obtained, which is uneconomical.

The composition of the present invention may contain various additives such as plasticizers, processing aids, anti-aging agents, crosslinking aids, crosslinking retarders, pigments, flame retardants, etc. as commonly practiced in the art. That is freedom. Also calcium carbonate, magnesium carbonate, clay.

About 5 to 100 parts by weight of fillers such as mica, reinforcing agents, and organic reinforcing agents such as lignin can be added to 100 parts by weight of the copolymer rubber or rubber mixture.

In the composition of the present invention, as mentioned above, the blending of carbon black does not improve heat aging resistance but tends to reduce it, so even if its addition is particularly required, the amount of carbon black blended with the copolymer rubber or It should be kept at most 10 parts by weight and usually less than 5 parts by weight per 100 parts by weight of the rubber mixture.

In order to maintain thermal stability and ensure an appropriate degree of crosslinking in the composition of the present invention, it is particularly preferable to add a metal compound to serve as an acid acceptor. Metal compounds that serve as such acid acceptors include:
Oxides, hydroxides, carbonates, carboxylates, silicates, borates, phosphites of metals from group 1 of the periodic table, oxides and basic carbonates of metals from group 1 Va of the periodic table, Basic carboxylate, basic phosphite, basic sulfite, tribasic ia
There are acid salts, etc. Specific examples include magnesia, magnesium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, quicklime, slaked lime, calcium carbonate, calcium stearate, zinc stearate, calcium phthalate, magnesium phosphite, and calcium phosphite.1. Zinc white, tin oxide, litharge, red lead, white lead, dibasic lead phthalate, dibasic lead carbonate, tin stearate, basic sulfuric acid
Examples include acid lead, basic lead sulfite, basic lead sulfite, and tribasic lead sulfate. The appropriate amount is 1 to 20 parts by weight per 100 parts by weight of the copolymer rubber or rubber mixture.

There is no particular restriction on the order in which the composition of the present invention is blended, but especially when using a silane coupling agent, it is very difficult to use a silicon compound that has been mixed and coated with a diluted or undiluted silane coupling agent. preferable. Furthermore, the composition may be blended by any means used in the conventional rubber processing field, such as mixing rolls, Banbury mixer 1, various kneaders, and the like.

The composition of the present invention usually has a temperature of 0.5 to 3 at 100 to 200'C.
It can be made into a crosslinked product by heating for 00 minutes.

Any method can be used for crosslinking, such as pressure molding using a mold, injection molding, steam can, air path, or heating using infrared rays, microwaves, or the like.

(Effects of the Invention) The crosslinked rubber products obtained from the composition of the present invention are particularly excellent in heat aging resistance and have inherent oil resistance.

In addition to its excellent properties such as ozone resistance and cold resistance, it is useful as a rubber material that can be adapted to a variety of needs.

(Examples) Examples 1 to 8 Comparative Examples 1 to 2 Each composition shown in Table 1 was kneaded with an open roll at 60 to 70°C to form a sheet, then put into a mold and heated at 160°C.
Pressure molding was carried out at 180 K (l)/cd for 30 minutes. Physical properties of each of the obtained crosslinked products were tested, and the results are shown in Table 2.

Comparative Example 1 is an example in which carbon black was used instead of a silicon compound, and the heat aging resistance test was conducted at 150°CX.
After 336 hours, it had already softened and measurement was impossible.

Comparative Example 2 is an example in which a conventionally most commonly used crosslinking agent different from the crosslinking agent of the present invention was used, and it can be seen that the heat aging resistance is inferior to that of the composition of the present invention.

In order to investigate the storage stability of each composition shown in Table 1, the Mooney viscosity [MLt +4 ( 100°C)],
Table 2 shows the difference based on the Mooney viscosity immediately after kneading.

In Table 1, the following were used for (1) to (15). In addition, in the following, EP: Epicadashi Hitrin,
PO: Propylene oxide.

EO: ethylene oxide, AGE: allyl glycidyl ether.

(1) Mooney viscosity [MLl +4 (100°C)]
(The same applies hereinafter) 55 (2) Molar ratio E P/PO = 50150, Mooney viscosity (3) Molar ratio EP/EO = 15/85, Mooney viscosity (4) Molar ratio E P/AG E = 90/10
, Mooney viscosity 35 (5) Molar ratio E P'/ P O/ E O = 40
/30/30, Mooney viscosity 85 (6) Molar ratio EP/PO/AGE=30/65/5
, Mooney viscosity γ0 (7) Molar ratio EP/EO/AGE=70/20/10
, Mooney viscosity 45 (8)-E/L, ratio EP/PO/EO/AGE=30
/30/30/10, Mooney viscosity 70 (9) "Carplex #6γ" Shionogi & Co., Ltd. trade name (10) CUO3H6Si per 100 parts by weight of the same product
4 parts by weight of (OC2H5)3 were added and mixed uniformly.
2 parts by weight of 3 were added and mixed uniformly.

Claims (1)

[Scope of Claims] An epichlorohydrin-propylene oxide rubber composition characterized by containing the following components (a) to (c). (a) Constituent units of the copolymer rubber or rubber mixture are 10 to 90 mol% of epichlorohydrin, 10 to 90 mol% of propylene oxide, and 0 to 60 mol% of ethylene oxide.
, 100 parts by weight of a copolymer rubber or rubber mixture containing 0 to 15 mol% allyl glycidyl ether (b) one or more silicon compounds selected from hydrated silicic acid, calcium silicate, and magnesium silicate 1
0 to 90 parts by weight (c) 0.1 to 8 parts by weight of a crosslinking agent made of heterocyclic polythiols or derivatives thereof