JPH0562147B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field of the Invention) The present invention relates to an epichlorohydrin-propylene oxide rubber composition, and particularly to a rubber composition that has excellent storage stability and heat aging resistance of a crosslinked product. (Prior Art) Epichlorohydrin-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 yet been widely used industrially. In addition, regarding the storage stability of the uncrosslinked composition,
In the case of conventional compositions, the viscosity of the composition itself increases significantly in a hot and humid environment, and strict control has been required when handling the composition under such an environment. (Objective of the Invention) The object of the present invention is to create an epichlorohydrin-propylene oxide rubber composition that not only has the properties previously possessed, but also has the heat aging resistance of crosslinked products and the storage stability of the composition, which have been disadvantageous in the past. It is about providing something. (Structure of the Invention) The present invention comprises (a) 10-90 mol% of epichlorohydrin, 10-90 mol% of propylene oxide, 0-60% of ethylene oxide, and 0-60% of allyl glycidyl ether from the constituent units of the copolymer rubber or rubber mixture.
15 mole% copolymer rubber or rubber mixture 100
Based on parts by weight, (b) 10 to 90 parts by weight of one or more silicon compounds selected from hydrous silicic acid, calcium silicate, and magnesium silicate; and (c) crosslinked polythiols containing heterocycles or derivatives thereof. agent
Carbon black substantially as a reinforcing filler is characterized in that it contains 0.1 to 8 parts by weight and 0.1 to 5 parts by weight of a silane coupling agent selected from compounds represented by the following general formulas () to (). This is an epichlorohydrin-propylene oxide based rubber composition. ClC ₃ H ₆ Si(OR) ₃ () (However, in the above general formulas () to (), R
represents a methyl group or an ethyl group) The copolymer rubber or rubber mixture which is component (a) in the present invention has a constitutional unit of 10 to 90 mol % of epichlorohydrin, preferably 20 to 80 mol %, and 10 to 10 mol % of propylene oxide. 90 mol%, preferably 20~
A copolymer rubber or rubber mixture is used in the range 80 mol%, ethylene oxide 0-60 mol%, preferably 0-40 mol%, allyl glycidyl ether 0-15 mol%, preferably 0-10 mol%. . Examples of the copolymer rubber include epichlorohydrin-propylene oxide binary copolymer, epichlorohydrin-propylene oxide-ethylene oxide ternary copolymer, epichlorohydrin-propylene oxide-allyl glycidyl ether ternary copolymer, epichlorohydrin-propylene Examples include oxide-ethylene oxide-allyl glycidyl ether quaternary copolymer. Examples of rubber mixtures include copolymer rubbers consisting of the above-mentioned components, as well as epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide binary copolymer, epichlorohydrin-allyl glycidyl ether binary copolymer, epichlorohydrin-ethylene oxide- A rubber made of an allyl glycidyl ether terpolymer is suitably mixed and used so that the mole % of each of the above constituent units falls within the range. 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 epichlorohydrin-ethylene oxide copolymer, the former structural unit is 5 to 95 mol%, preferably 10 to 90 mol%, epichlorohydrin-ethylene oxide copolymer
In the allyl glycidyl ether copolymer, the latter structural unit is preferably 15 mol% or less, preferably 10 mol% or less. For terpolymer, epichlorohydrin-propylene oxide-ethylene oxide copolymer, epichlorohydrin 10
~90 mol%, preferably 20-80 mol%, propylene oxide 5-80 mol%, preferably 10-70 mol%, ethylene oxide 5-80 mol%, preferably 10-70 mol%, epichlorohydrin-
In the propylene oxide-allyl glycidyl ether copolymer, epichlorohydrin is 5 to 90 mol%, preferably 10 to 80 mol%, propylene oxide is 5 to 90 mol%, preferably 10 to 80 mol%, and allyl glycidyl ether is 15 mol%, preferably is 10
It is preferable that the amount is less than mol%. 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 the epichlorohydrin content is less than 10 mol%, the vulcanization rate and oil resistance will decrease, and if it exceeds 90 mol%, the cold resistance will decrease, so it is preferable. do not have. If the propylene oxide content is less than 10 mol%, cold resistance will decrease, and if it exceeds 90 mol%, 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 as it may cause Allyl glycidyl ether is introduced in order to maintain particularly excellent ozone resistance, but if it exceeds 15 mol %, it is not preferable because oil resistance decreases and the tendency for embrittlement after heat aging becomes significant. The silicon compound as component (b) used in the present invention is:
It is composed of one or a mixture of two or more selected from hydrous silicic acid, calcium silicate, and magnesium silicate, and those commonly used in the rubber industry can be used as they are. 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 obtained vulcanizate will be impaired, so it is preferable. do not have. The crosslinking agent consisting of heterocyclic polythiols or derivatives thereof, which is the component (c) used in the present invention, is generally known as dimercaptopyrazines or derivatives thereof (Japanese Patent Publication No. 14468/1983),
dimercaptoquinoxalines or derivatives thereof (Japanese Patent Publication No. 58-14469), dimercaptotriazoles or derivatives thereof (Japanese Patent Publication No. 57-46463),
Dithiohydantoins or derivatives thereof
-14467 Publication, JP-A-57-34160, JP-A-Sho
57-126854), trithiocyanuric acid or its derivatives (Japanese Patent Publication No. 1982-36926), dimercaptothiadiazole or its derivatives (Japanese Patent Publication No. 1982-36926),
Publication No. 3439). Specific examples of these include 2,3-dimercaptopyrazine, 6
-Methylquinoxaline-2,3-dithiocarbonate, 3,5-dimercapto-1-phenyl-
1,2,4-triazole, 5,5-dimethyl-
Examples include 2,4-dithiohydantoin, trithiocyanuric acid, and 6-dibutylamino-2,4-dimercapto-s-triazine.
The appropriate amount is 0.1 to 8 parts by weight, preferably 0.3 to 6 parts by weight, per 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 recommended to use a silane coupling agent selected from compounds represented by the following general formulas () to () as component (d). Very preferred. ClC ₃ H ₆ Si(OR) ₃ () (However, in the above general formulas () to (), R
(represents a methyl group or an ethyl group) Although the silane coupling agent in the composition of the present invention has almost no effect on the crosslinked physical properties depending on its type, particular care must be taken when handling uncrosslinked formulations. It has been found that there are points to be made. That is, in the case of silane coupling agents represented by the following general formulas () to (), especially () and (), there are some difficulties in viscosity stability when storing uncrosslinked formulations, and it is difficult to handle them in normal handling. Although there are no disadvantages in this case, it has been found that when stored in a particularly hot and humid environment, adverse effects appear, and that special care should be taken when handling in such an environment. HSC ₃ H ₆ Si(OR) ₃ () HSC ₂ H ₄ Si(OR) ₃ () H ₂ NC ₃ H ₆ Si(OR) ₃ () H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si(OR) ₃ () NH ₂ CONHC ₃ H ₆ Si(OR) ₃ () (However, in the above general formulas () to (), R
(represents a methyl group or an ethyl group) On the other hand, the silane coupling agents represented by the general formulas () to () used in the present invention have very little viscosity stability under such environments and are extremely useful in practical use. It was found to be an effective additive for 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 also contain various additives such as plasticizers, processing aids, anti-aging agents, crosslinking aids, crosslinking retarders, pigments, flame retardants, etc. as commonly practiced in the technical field. is free. Further, about 5 to 100 parts by weight of inorganic fillers and reinforcing agents such as calcium carbonate, magnesium carbonate, clay, and mica, 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 addition of carbon black tends to reduce heat aging resistance rather than improve it, so it should be avoided except for the purpose of obtaining a black product, and even when added, it should be avoided. It should be less than 5 parts by weight per 100 parts by weight of polymeric rubber or 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. Such metal compounds that serve as acid acceptors include oxides, hydroxides, carbonates, carboxylates, silicates, borates, phosphites of group metals of the periodic table, and group metals of the periodic table. Group A metal oxides, basic carbonates, basic carboxylates,
There are basic phosphites, basic sulfites, tribasic sulfates, 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, calcium phosphite, and zinc oxide. , tin oxide, litharge, white lead, red lead, dibasic lead phthalate, dibasic lead carbonate, tin stearate, basic lead phosphite, basic tin phosphite, basic lead sulfite, tribasic sulfuric acid Examples include lead. The appropriate amount is 1 to 20 parts by weight per 100 parts by weight of the copolymer rubber or rubber mixture. Although there is no particular restriction on the order in which the compositions of the present invention are contained, it is particularly preferable that the silane coupling agent be diluted or undiluted and mixed with a silicon compound in advance to be used as a coating silicon compound. Furthermore, the composition can be blended using any means used in the conventional rubber processing field, such as mixing rolls, Banbury mixers, various kneaders, and the like. The composition of the present invention can be made into a crosslinked product by heating it usually at 100 to 200°C for 0.5 to 300 minutes. Any method can be used for crosslinking, such as pressure molding using a mold, injection molding, steam can, air bath, or heating using infrared rays, microwaves, or the like. (Effects of the Invention) The composition of the present invention has excellent storage stability, and the crosslinked rubber products obtained therefrom are particularly excellent in heat aging resistance, and have inherent oil resistance, ozone resistance, cold resistance, etc. In addition to its excellent properties, it is useful as a rubber material that can be adapted to a variety of needs. (Examples) Examples 1 to 2 Comparative Examples 1 to 10 Each composition shown in Table 1 was kneaded with an open roll at 60 to 70°C and formed into a sheet, which was then put into a mold.
Pressure molding was carried out at 160° C. and 80 kg/cm ² for 30 minutes. Physical property tests were conducted on each of the crosslinked products obtained, and the results are shown in Table 2. In addition, in order to examine the storage stability of each composition shown in Table 1, Mooney viscosity [ ML1 ₊₄
(100°C)] and the differences are shown in Table 2 based on the Mooney viscosity immediately after kneading. Comparative Example 1 and Comparative Example 4 are examples using the hydrous silicic acid and magnesium silicate used in Example 1 and Example 2, respectively, before being treated with a silane coupling agent, and the basic physical properties and As shown by the physical property value of compression set, the curing was not sufficient, and the heat aging resistance was also poorer than that of the present invention. Comparative Examples 2 to 3 and Comparative Examples 5 to 7 are examples in which silane coupling agents of different types from the silane coupling agent of the present invention were used, and all of these compositions were stored better than the composition of the present invention. Stability is extremely poor. Comparative Example 8 is an example in which a conventionally most commonly used crosslinking agent different from the crosslinking agent of the present invention was used, and the heat aging resistance was significantly inferior to that of the composition of the present invention. However, it was already softened and measurement was impossible. Comparative Example 9 and Comparative Example 10 are examples in which carbon black was used instead of a silicon compound, and examples in which a silicon compound and carbon black were used in combination, and in both cases, the heat aging resistance was significantly inferior to that of the composition of the present invention. It had already softened after 336 hours at ℃. The storage stability of the composition is also significantly worse than that of the composition of the present invention. In Table 1, the following were used for (1) to (14). In addition, in the following, EP: epichlorohydrin, PO: propylene oxide, EO: ethylene oxide, AGE: allyl glycidyl ether. (1) Molar ratio EP/PO=50/50, Mooney viscosity 70 (2) Molar ratio EP/AGE=90/10, Mooney viscosity 35 (3) Molar ratio EP/PO/EO=40/30/30, Mooney Viscosity 85 (4) Molar ratio EP/PO/AGE=70/20/10, Mooney viscosity 45 (5) "Carplex #67" Shionogi Pharmaceutical Co., Ltd. trade name (6) C1C ₃ H per 100 parts by weight of the same product _6Si
(OC ₂ H ₅ ) ₃ added to 4 parts by weight and mixed uniformly (7) HSC ₃ H ₆ Si per 100 parts by weight of the same product
(OCH ₃ ) ₃ added with 4 parts by weight and mixed uniformly (8) H ₂ NC ₃ H ₆ Si per 100 parts by weight of the same product
(OCH ₃ ) ₃ was added to 4 parts by weight and mixed uniformly (9) HSC ₂ H ₄ Si per 100 parts by weight of the same product.
4 parts by weight of (OCH ₃ ) ₃ were added and mixed uniformly (10) 2 parts by weight of HSO ₃ H ₆ Si (OCH ₃ ) ₃ per 100 parts by weight of "Silmos T" (trade name of Shiraishi Kogyo Co., Ltd.) (11) "Hytron" Takehara Chemical Industry Co., Ltd. trade name (12) Per 100 parts by weight of the same product (13) Added 1.5 parts by weight of HSC ₂ H ₄ Si to 100 parts by weight of the same product and mixed uniformly.
(OCH ₃ ) 1.5 parts by weight of ₃ were added and mixed uniformly (14) H ₂ N・CONH・
Uniformly mixed with 1.5 parts by weight of C ₃ H ₆ Si (OCH ₃ ) ₃

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【table】

Claims (1)

[Scope of Claims] 1. An epichlorohydrin-propylene oxide rubber composition substantially free of carbon black as a reinforcing filler, characterized by containing the following components (a) to (d). (a) The constituent units of the copolymer rubber or rubber mixture are 10 to 90 mol% epichlorohydrin, 10 to 90 mol% propylene oxide, and 0 ethylene oxide.
~60 mol%, allyl glycidyl ether 0-15
Copolymer rubber or rubber mixture in mole %
100 parts by weight (b) One or more silicon compounds selected from hydrous silicic acid, calcium silicate, and magnesium silicate 10 to 90 parts by weight (c) Crosslinking agent consisting of heterocyclic polythiols or derivatives thereof 0.1 to 8 parts by weight (d) Silane coupling agent selected from compounds represented by the following general formulas () to ()
0.1 to 5 parts by weight ClC ₃ H ₆ Si (OR) ₃ () (However, in the above general formulas () to (),
R represents a methyl group or an ethyl group)