KR19980014733A - Vulcanized rubber composition - Google Patents

Abstract

The present invention relates to a rubber composition comprising at least one nitrile group-containing rubber, chloroprene rubber, and ethylene propylene rubber as a substrate, at least one member selected from the group consisting of a monofunctional epoxy compound, a glycidyl ether type epoxy compound and a glycidyl ether type epoxy compound And an epoxy compound of the formula (I)

(Wherein R ¹ is a hydrogen atom or an alkyl group, R ² is an alkyl group or a phenyl group, R ³ is an alkyl group, an alkoxy group or an alkenyloxy group, and n is 1 or 2) Of the rubber composition.

Description

Vulcanized rubber composition

The present invention relates to a vulcanized rubber composition used in the presence of Freon and / or refrigerator oil and a molded product thereof.

Currently, the destruction of the ozone layer is becoming a serious problem, and some of the freon gas that destroys ozone has been determined to be disposed of within a few years. Therefore, CFCs (CFCs, CFCs, and CFCs), such as R-11 (CCl ₃ F) and R-12 (CCl ₃ F ₂ ), which are used as refrigerants for refrigerators and air conditioners, from _{the, R-22 (CHClF 2)} , R-123 (CHClFCClF 2) ( freon comprised of four elements of C, H, Cl and F) of HCFC such _{as, R-134a (CH 2 FCF} 3), R-407c (Ozone destruction rate: 0) consisting of HFC (C, H and F elements consisting of three elements such as CH ₂ F ₂ / CF ₃ CHF ₂ / CH ₂ FCF ₃ mixture (23/25/52 wt% . In response to this, the refrigerator oil (lubricating oil of the refrigerator) used also changes from the mineral oil used in combination with the conventional freon to an ester type or polyalkylene glycol type oil.

With the replacement of coolant and refrigerator oil, rubber products suitable for such replacements have also been desired. Conventionally used fluoroelastomers are corroded with the new Freon R-134a, and the chloroprene rubber also promotes the hydrolysis of the ester oil, deteriorating the refrigerator oil. Therefore, vulcanized rubber compositions using nitrile rubber or chlorinated polyethylene have been studied as rubbers for new Freon use.

For example, JP-A-3-250037 discloses a vulcanized rubber composition containing nitrile rubber, chlorinated polyethylene and organic peroxides, and JP-A-5-140334 discloses a vulcanized rubber composition containing chlorinated rubber (chlorinated polyethylene, chloroprene rubber, JP-A-6-128415 proposes a rubber mixed composition prepared by adding an organic peroxide to nitrile rubber and a chlorinated ethylene-propylene copolymer rubber kneaded product.

However, when a vulcanized rubber composition containing chlorinated rubber is used in refrigerating machine oil, chlorine of these components acts as a catalyst to accelerate the hydrolysis of refrigerator oil, thereby causing a problem of lowering viscosity and lowering lubricity. This tendency is particularly noticeable when freon coexists or when the refrigerating oil is an ester oil. Further, JP-A-5-140334 discloses that a vulcanized rubber composition contains a metal oxide, a metal hydroxide, a metal soap and the like, but such a metal compound further promotes the hydrolysis of the ester oil.

JP-B-17930 discloses a vulcanized rubber composition for an O-ring molded article in which 10 to 150 parts by weight of carbon black is added to 100 parts by weight of a hydrogenated nitrile rubber in JP-A-5-65369, Discloses vulcanized rubber compositions composed of hydrogenated nitrile rubbers and organic peroxides having a Mooney viscosity of 100 or more (ML _{1 + 4} (100 ° C)). However, the vulcanized rubber compositions obtained by these techniques are resistant to chlorofluorocarbons From the heat screen of the refrigerator oil, it was not always satisfactory.

An object of the present invention is to provide a vulcanized rubber composition which is excellent in resistance to freon and refrigerator oil without substantially promoting deterioration (for example, hydrolysis of ester oil) of refrigerator oil.

The inventors of the present invention have found that vulcanized rubber compositions having remarkably improved resistance to freon and refrigerator oil can be obtained by virtue of not accelerating deterioration of refrigerator oil including hydrolysis of ester oil by adding a specific epoxy compound to a specific rubber composition .

Further, the present inventors have found that the same effect can be obtained by blending a specific aluminum complex with a specific rubber composition.

Particularly, according to the present invention, when a monofunctional epoxy compound is contained in at least one of a nitrile group-containing rubber, a chloroprene rubber, and an ethylene propylene rubber as a base material, To provide a rubber composition in use.

According to the present invention, there is also provided a rubber composition comprising a base material, which is composed of at least one nitrile group-containing rubber, chloroprene rubber, and ethylene propylene rubber and contains a glycidyl ether type epoxy compound therein, A rubber composition is provided.

Further, according to the present invention, there is provided a rubber composition comprising as a base material at least one nitrile group-containing rubber, chloroprene rubber, and ethylene propylene rubber,

And / or a freezer oil (hereinafter, referred to as " R ") containing a compound represented by the formula: wherein R ¹ is a hydrogen atom or an alkyl group, R ² is an alkyl group or a phenyl group, R ³ is an alkyl group, an alkoxy group or an alkenyloxy group, To provide a rubber composition in use.

The nitrile group-containing rubbers used here include various types of nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR) and modified nitrile rubbers (for example, carboxylated nitrile rubber (CNBR)), Also called rubber. The nitrile rubber used in the present invention is not particularly limited as to the nitrile content, the hydrogenation rate, the molecular weight, the Mooney viscosity and the like, and a plurality of nitrile rubbers, hydrogenated nitrile rubbers and / or modified nitrile rubbers can be used in combination.

Examples of the chloroprene rubber (CR) include all types of 2-chlorobutadiene rubber, and CR is divided into a yellow mold, a non-yellow mold and a high crystal mold. In the present invention, any of these forms can be used However, it is preferable to use CR of non-yellowing molding. By using non-yellowing molded CR, deterioration of refrigerator oil is suppressed more effectively than when using other types of CR.

The ethylene propylene rubber (EP, EPDM) is a rubber product mainly composed of a copolymer of ethylene and propylene, and in some cases, containing a small amount of a diene component. According to the present invention, it is preferable to use, as the diene component, EPDM containing dicyclopentadiene, ethylidene norbornene or 1,4-hexadiene, in particular ethylidene norbornene. By using this type of EPDM, the resistance of the vulcanized rubber composition to freon or refrigerator oil can be improved more efficiently. As the raw material rubber of the present invention, a mixture of two or more of the above-mentioned rubbers may be used, and various known rubbers other than the above-mentioned rubbers may be used in combination. Examples of such rubbers include natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), butyl rubber (IIR), urethane rubber (U) There can be mentioned fluorine rubber (F), acrylic rubber (ACM), epichlorohydrin rubber (CO), chlorosulfonate polyethylene (CSM) and chlorinated polyethylene (CM) But is not limited thereto. However, according to the present invention, the total amount of the nitrile rubber, chloroprene rubber and ethylene propylene rubber is preferably 40% by weight or more, more preferably 50% by weight or more, and most preferably 80% by weight or more based on the total rubber (I.e., the weight of the material after excluding the epoxy compound, vulcanizing agent, filler, etc. in the rubber composition).

According to the present invention, it is particularly preferable to use a hydrogenated nitrile rubber. When the hydrogenated nitrile rubber is used, the vulcanized rubber composition is remarkably resistant to the refrigerant and refrigerant, and the deterioration of the refrigerating machine oil can be controlled to an extremely low level. Hydrogenated nitrile rubber (hereinafter referred to as HNBR) is Zetpol (trade name) manufactured by Nippon Zeon Co., Ltd. and Therban (trade name) manufactured by Bayer. HNBR is a center value, and the iodine value preferably has 50% or less, more preferably 3 to 40%, and most preferably 8 to 30%. Resistance to freon and refrigerator oil can be increased by using HNBR having a central iodine value of 50% or less (high hydrogenation rate), and rubber elasticity at low temperature can be preserved by using a rubber having a low hydrogenation rate. Therefore, the central value of the nitrile content of the HNBR is preferably about 15 to 60%, more preferably 30 to 55%, and most preferably 40 to 50%. The resistance to chlorofluorocarbons and refrigerator oils can be increased by using HNBR having a nitrile content of at least 15%, in particular at least 30%, and low temperature resistance can be maintained by using rubber having a nitrile content of at most 60%, in particular at most 50% . The Mooney viscosity (hereinafter referred to as Mooney viscosity) as a center value of ML _{1 + 4} (100 ° C) is preferably 55 to 100, more preferably 65 to 95, and most preferably 75 to 90. When HNBR having a Mooney viscosity within the above range is used, the vulcanized rubber composition can maintain high resistance to freon and refrigerator oil, and is also excellent in flexibility and heat resistance.

Liquid nitrile rubber (hereinafter referred to as liquid NBR) may be used in combination as a raw material for the vulcanized rubber composition of the present invention. Liquid NBR refers to nitrile rubber which shows fluidity at room temperature, and rubber which does not show fluidity at room temperature is hereinafter referred to as solid rubber.

Here, the room temperature means 0 to 50 占 폚, and particularly 15 to 35 占 폚. The liquid NBR includes N280 (trade name) manufactured by Japan Synthetic Rubber Co., Ltd. and Nipol 1312 and Nipol DN601 (trade name) manufactured by Nippon Zeon Co., Ltd. For example, when 100 parts by weight of the solid rubber is added in an amount of 50 parts by weight or less, particularly 30 parts by weight or less, the hardness of the vulcanized rubber composition can be reduced without spoiling the effect of the present invention. Further, the resistance to refrigerant and freezing oil can be further improved according to the conditions of use of the vulcanized rubber composition. Particularly, this effect is remarkable when the solid rubber is mainly HNBR. The liquid NBR is preferably used in an amount of not more than 50 parts by weight, more preferably not more than 30 parts by weight, most preferably not more than 20 parts by weight, based on 100 parts by weight of the HNBR.

Vulcanized rubbers are well known per se and can be obtained by crosslinking uncrosslinked rubbers using peroxides. The peroxides used in the crosslinking are not particularly limited, and examples thereof include di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 1,1-di (t-butylperoxy) Dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert- butylperoxy) hexyne- 1,3-di (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t- butylperoxyisopropylcarbonate, (T-butylperoxy-m-isopropyl) benzone, benzoyl peroxide, etc. The peroxide may be pre-mixed with carbon black , Calcium carbonate, rubber, etc. The peroxide is used in an amount of preferably 0.5 to 30 parts by weight, more preferably 1 to 15 parts by weight based on 100 parts by weight of the rubber, and the amount of the peroxide is 0.5 part by weight Or less, the vulcanized rubber composition for the refrigerant and the freezing oil The chloroprene rubber or the carboxylated nitrile rubber may be a mixture of a metal oxide such as magnesium oxide and zinc oxide or a metal oxide such as zinc oxide, For example, 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, and most preferably 2 to 10 parts by weight of magnesium oxide per 100 parts by weight of the chloroprene rubber. The rubber other than HNBR having a hydrogenation rate of 100% can be crosslinked using a sulfur and / or vulcanization accelerator. The above-mentioned crosslinking agent includes triallyl isocyanurate, ethylene (Meth) acrylates, such as glycol dimethacrylate, trimethylolpropane trimethacrylate, polybutadiene, polyfunctional methacrylate monomers and polyhydric alcohol A thiuram type vulcanization accelerator such as tetramethyl thiuram disulfide (TT), tetraethyl thiuram disulfide (TET), and tetrabutyl thiuram disulfide (TBT), and dibenzothiazyl disulfide and Thiol accelerators such as 2-mercaptobenzothiazole, guanidine accelerators such as trimethylthiourea and 1,3-diphenylguanidine, and sulfenamide-type accelerators such as N-cyclohexyl-2-benzothiazolylsulfenamide A dithiocarbamate type accelerator such as zinc dimethyldithiocarbamate or diethyldithiocarbamate, a xanthene type accelerator such as zinc butyloxantogenate, hexamethylenetetramine or n-butylaldehyde aniline, It can be further mixed with the agent.

The molding can be carried out by using an injection molding machine, a compression molding machine, a vulcanizing press or the like, for example, by performing the crosslinking at 150 to 250 DEG C for 3 to 60 minutes, and the postcuring is carried out at 120 to 220 DEG C in an oven at 1 to 24 Time.

A feature of the present invention resides in that the above-mentioned vulcanized rubber composition contains a specific epoxy compound or a specific aluminum complex. By doing so, it is possible to obtain a vulcanized rubber composition which exhibits excellent resistance to freon and refrigerator oil without substantially promoting deterioration of the refrigerator oil. In particular, when used in an ester-based freezer oil, hydrolysis of the freezer oil is suppressed. Degradation due to hydrolysis and the like is evaluated by the total acid number of the oil, and as the deterioration progresses, the total acid number becomes large. In the present invention, the increase in total acid number is suppressed. In addition, the vulcanized rubber composition of the present invention in which a specific epoxy compound is blended exhibits excellent water resistance, solvent resistance, electrical characteristics, mechanical properties, adhesion properties and heat resistance as compared with a vulcanized rubber composition not using an epoxy compound.

Specific epoxy compounds that can be used in the present invention include monofunctional epoxy compounds (compounds represented by the following formula (A), particularly those containing a group of formula (A ') in the molecule) and glycidyl ether- Ether containing the group of B) in the molecule.

Examples of such epoxy compounds include monofunctional epoxy compounds such as epoxy butane, epoxy butene, epoxycyclohexane, epoxy norbornane, epoxy hexene, epoxy octene, glycidol and glycidyl phthalimide; Glycidyl glycidyl ether, glycidyl glycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, and triglycidyl tris (2-hydroxyethyl) A cidyl ether type epoxy compound; And methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, cyclohexyl glycidyl ether, nonyl glycidyl ether, Methyl ethylcyclohexyl glycidyl ether, 2-ethylhexyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, icosyl glycidyl ether, phenyl glycidyl ether, tolyl glycidyl Ether, benzyl glycidyl ether, P-tert-butylphenyl glycidyl ether, dibromophenyl glycidyl ether, naphthyl glycidyl ether, lauryl glycidyl ether, allyl glycidyl ether, Functional glycidyl ether type epoxy compounds such as phenyl glycidyl penta (ethyleneoxy) ether, lauryl-glycidylpentadeca (ethyleneoxy) ether and the like, Can be used in the present invention Examples of the epoxy compound that can be used are not limited to the above-exemplified epoxy compounds. These epoxy compounds may be used alone or as a mixture of two or more thereof.

However, it is preferable to use a mono-functional glycidyl ether type epoxy compound as the epoxy compound. By doing so, the deterioration of the refrigerating machine oil can be controlled to a lower level and the resistance of the vulcanized rubber composition to the refrigerant and freezer oil can be improved more efficiently. When a compound having a plurality of epoxy groups in one molecule is used, low temperature resistance and rubber elasticity of the vulcanized rubber composition are slightly reduced. In addition, although it is possible to suppress the increase of the total acid number of the refrigerator oil, in some cases, a colloidal precipitate is formed depending on the kind of the refrigerator oil and the use conditions.

Further, the epoxy compound preferably contains an alkyl group and / or an alkenyl group. The use of an epoxy compound which does not contain an alkyl group or an alkenyl group can suppress the increase in total acid number of the refrigerating machine oil, but a colloidal sediment can be formed depending on the kind of the refrigerating machine and the operating conditions. The epoxy compound preferably has an epoxy equivalent (number of grams of compound containing 1 g equivalent of epoxy group) of 100 or more, especially 170 or more. If the epoxy equivalent is too small, a colloidal precipitate may be formed depending on the type of refrigerator oil and the conditions of use. An epoxy compound having a branched alkyl and / or alkenyl group such as an allyl group and a vinyl group can also be used. Especially preferred is an epoxy compound having an alkyl group having 7 to 15 carbon atoms. By using such a compound, the increase in the total acid number of the refrigerator oil is more efficiently suppressed, and the resistance of the vulcanized rubber composition to the refrigerant and refrigerant oil is simultaneously improved. If the molecular weight of the epoxy compound is 1,000 or less, particularly 300 or less, the vulcanized rubber composition becomes flexible. When the molecular weight of the epoxy compound is 1,000 or more, especially 3,000 or more, there is little secretion.

According to the present invention, the epoxy compound is used in an amount of preferably 0.1 to 50 parts by weight, more preferably 1 to 40 parts by weight, and most preferably 3 to 30 parts by weight based on 100 parts by weight of the rubber. If the amount of the epoxy compound is less than 0.1 part by weight, the improvement in the resistance of the vulcanized rubber composition to freezing and refrigerating machine oil is improved, It becomes insufficient.

Specific aluminum complexes usable in the present invention are compounds represented by the following formulas (hereinafter referred to as compound (I)),

(Wherein R ¹ represents a hydrogen atom or an alkyl group, R ² represents an alkyl group or a phenyl group, R ³ represents an alkyl group, an alkoxy group or an alkenyloxy group, and n represents 1 or 2)

Examples of the compound (I) include mono- (oleo-3-oxobutanoate-O ¹ , O ³ ) -bis- (2-propanolate) -aluminum (III) (hereinafter referred to as OBPA) (III) diisopropoxide ethyl acetoacetate (hereinafter referred to as AIEA), bis (oleyl-3-oxobutane (III) diacetoxyacetate Eight furnace -O ^1, O ³⁾ - mono- (2-propanol rate) - aluminum (ⅲ), mono (stearyl-3-oxo-butanoate ¹ -O, O ³⁾ bis-hydroxy-aluminum (ⅲ), mono (ethyl-3-oxo-butanoate -O ^1, O ³⁾ - bis-hydroxy-aluminum (ⅲ), mono- (ethoxy-3-oxo-butanoate -O ^1, O ³ (III), mono (ethoxy-3-oxobutanoate-O ¹ , O ³ ) -bis- (2-propanolate) 3-oxo-butanoate -O ^1, O ³⁾ - bis - (2-propanol rate) - aluminum (ⅲ), mono- (oleyl-3-oxo-3 A propionate -O ^1, O ³⁾ bis (2-propanol rate) - aluminum (Ⅲ) and the like, but is not compound (Ⅰ) is limited to said compounds. The compound (I) may be used alone or as a mixture of two or more thereof. However, in the compound (I), it is preferable that R ¹ is an alkyl group having 1 to 5 carbon atoms, R ² is an alkyl group having 1 to 5 carbon atoms, and R ³ is an alkoxy group having 1 to 25 carbon atoms. More preferably, R ¹ is an isopropyl group or a sec-butyl group, R ² is a methyl group, R ³ is an ethoxy group or -OC ₁₈ H ₃₅ , and n is 1. One of these compounds, especially OBPA (R ¹ = isopropyl group, R ² = methyl group, R ³ = OC ₁₈ H ₃₅ , n = 1), ABEA (R ¹ = sec-butyl group, R ² = R ³ = ethoxy, n = 1), or AIEA (R ¹ = isopropyl, R ² = methyl, R ³ = ethoxy, by selecting the n = 1) as the compound (ⅰ), freon and refrigerating machine oil for The resistance of the rubber composition is further improved remarkably, and the increase in the total acid number of the refrigerator oil is more strongly suppressed.

More preferred examples of the above-mentioned compound (I) are shown below.

According to the present invention, the compound (I) is used in an amount of preferably 0.01 to 20.0 parts by weight, more preferably 0.05 to 10.0 parts by weight, and most preferably 0.1 to 5.0 parts by weight, based on 100 parts by weight of the rubber. If the amount of the compound (I) is less than 0.01 part by weight, the improvement of the resistance of the rubber composition to freezing and refrigerating machine oil and the reduction of the total acid number of the freezer oil become insufficient, and if it is more than 20 parts by weight, the total acid number of the refrigerator oil is not further reduced.

In a more preferred embodiment of the present invention, the above-mentioned epoxy compound and compound (I) are used in combination in the amounts described above. By using such a combination, the resistance of the rubber composition to the refrigerant and refrigerant oil and the total acid number of the freezer oil are reduced to a lower level.

The above-mentioned vulcanized rubber composition of the present invention containing a specific epoxy compound and / or compound (I) can suppress deterioration of refrigerator oil. In particular, when used in the presence of an ester-type freezer oil, the composition of the present invention exerts the advantage that the total number of acid values of the ester oil becomes smaller as compared with a conventional vulcanized rubber composition containing no epoxy compound and compound (I).

Further, the vulcanized rubber composition of the present invention may contain at least one selected from the group consisting of HFC (for example, R-134a, R-32, R-125, R-143a, R-407c, R- , R-22, R-123) and CFC (for example, R-11, R-12); Various types of refrigerating machine oil such as ester oil, polyalkylene glycol oil, ether oil, polycarbonate oil, paraffin and naphthenic mineral oil, alkylbenzene, poly-α-olefin and the like; And excellent resistance to these mixtures.

This effect is particularly remarkable in the epoxy compound-containing vulcanized rubber composition of the present invention.

Further, the composition of this type of the present invention is superior in water resistance, solvent resistance, electrical characteristics, mechanical properties, adhesion properties and heat resistance as compared with other vulcanized rubber compositions containing no epoxy compound.

Although the present invention is not limited by a particular theory, it is conceivable that the deactivation of the impurities contained in the nitrile raw rubber by the epoxy compound and / or the compound (I) exerts the effect of the present invention. The nitrile rubber contains a small amount of soap, a coagulant, an iron- or cobalt-containing metal catalyst, etc., remaining after polymerization and hydrogenation, and the release of these impurities into the freezer flow path causes deterioration of the freezer oil, It inhibits crosslinking. If crosslinking is inhibited, the resistance of the vulcanized rubber composition to the refrigerant and refrigerant oil is reduced. On the other hand, in the case of the vulcanized rubber composition in which the epoxy compound and / or the compound (I) is added according to the present invention, such impurities are inactivated through reaction with an epoxy adduct or an aluminum complex, that is, the compound (I) As shown, the rubber composition is completely crosslinked, exhibits high resistance to freon and refrigerator oil, and does not cause deterioration of the refrigerator oil because these impurities are not released into the refrigerator oil. Of the epoxy compounds, monofunctional epoxy compounds or glycidyl ether type epoxy compounds are most effective because they have terminal groups other than epoxy groups or are stable in molecules and have relatively high polarity ether bonds The reaction product of the epoxy group and the impurity is easily trapped in the nitrogen rubber through the terminal and the intramolecular part. Particularly, when the above-mentioned epoxy compound has an alkyl group (in particular, a molecular alkyl group) or an alkenyl group, or has an epoxy equivalent of 170 or more, the reaction product of an epoxy group and an impurity is easily trapped in the nitrile rubber through a hydrocarbon radical or the like. Further, when the refrigerator oil, particularly the ester refrigerating machine oil, is degraded, an acid such as a carboxylic acid is formed, and the formed acid further accelerates the deterioration of the refrigerator oil. However, when the vulcanized rubber composition of the present invention is used, since the epoxy group reacts with the acid to inactivate the acid, it is considered that acceleration of deterioration of the refrigerator oil can be prevented.

In addition to the above-mentioned components, the vulcanized rubber composition of the present invention can be produced by using the SAF (particle diameter: 11 to 19 nm), ISAF (particle diameter: 20 to 25 nm), HAF (particle diameter: 26 to 30 nm) Carbon black such as GPF (particle diameter: 49 to 60 nm), SRF (particle diameter: 61 to 100 nm), FT (particle diameter: 101 to 200 nm) and MT (particle diameter: 201 to 500 nm) . In this regard, each of SAF-MT represents the particle size classification in the manufacturing process. Further, an antioxidant such as an ozone deterioration inhibitor and an antioxidant may be mixed. Examples thereof include 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, phenyl-1-naphthylamine, alkylated diphenylamine, p (p- toluenesulfonylamide) di Phenylenediamine, N, N'-diphenyl-p-phenylenediamine, 2,6-di-tert-butyl Methylphenol, 4,4'-bis (?,? - dimethylbenzyl) diphenylamine, 4,4'-dithiobis (3-methyl- 1,2-dihydroquinoline polymer, a reaction product of diphenylamine and acetone, 2,5-di-tert-butylhydroquinone, 2-mercaptobenzimidazole, 2- mercaptomethylbenzamidazole, 2- Zinc salts of mercapto benzimidazole, nickel dibutyl dithiocarbamate, tributyl thiourea, tris (nonylphenyl) phosphite, and dilauryl thiodipropionate.

In addition, auxiliary auxiliaries such as triallyl isocyanurate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, polyfunctional methacrylate monomer, and polyhydric alcohol (meth) acrylate peroxide can be mixed.

In addition to the above components, the vulcanized rubber composition of the present invention may contain various additives conventionally used in the rubber composition. Examples thereof include reinforcing materials such as fine silica; Fillers such as talc, clay, graphite, calcium silicate, calcium carbonate, and barium sulfate; Reinforcing fibers such as aramid fiber, carbon fiber and glass fiber, a pressure-sensitive adhesive, a plasticizer, a colorant, and a processing aid.

The production method of the vulcanized rubber composition of the present invention is not particularly limited, and can be produced by the rubber kneading vulcanization method which has been conventionally used. For example, an essential component is kneaded by using an open roller, a Banbury mixer, a press kneader, an extruder or the like, and vulcanization is performed in a predetermined shape.

The vulcanized rubber composition of the present invention hardly accelerates deterioration of refrigerating machine oil, but exhibits excellent resistance to freon and refrigerator oil. Therefore, the vulcanized rubber composition of the present invention is useful as a molding material for rubber parts (for example, an O-ring, a sealing sleeve, a packing, a hose, and a tube) used in refrigerating machines such as refrigerators and air conditioners, As shown in Fig. The vulcanized rubber composition of the present invention is excellent in water resistance, solvent resistance, electrical characteristics, mechanical properties, adhesion properties and heat resistance as compared with conventional vulcanized rubber compositions containing no epoxy compound and compound (I) It is also suitable for use as a composite material of metal and rubber, and as an adhesive material.

The present invention also includes a molded article obtained from the above-mentioned vulcanized rubber composition, such as an O-ring, a sealing ring, a packing, a hose, a tube and the like. Such a vulcanized product hardly accelerates deterioration of refrigerating machine oil. In addition, HFC (for example, R-134a, R-32, R-125, R-143a, R-407c, R- Various freons such as HCFC (for example, R-22, R-123) and CFR (for example, R-11 and R-12); Ester oil, polyalkylene glycol oil, ether oil, polycarbonate oil, paraffin and naphthenic mineral oils, alkylbenzenes, poly-α-olefins and the like; And excellent resistance to these mixtures. The vulcanization molded article of the present invention is particularly advantageous when used in a refrigeration machine using an ester oil which is easily hydrolyzed, such as a refrigerator and an air conditioner.

(Example)

Hereinafter, the present invention will be described in detail with reference to examples.

Rubber samples of various formulation types as shown in Tables 1 to 7 were prepared and subjected to an immersion test using Freon and refrigerator oil. In this regard, the units of each formulation type shown in the table are parts by weight. Each rubber was kneaded with a compounding agent using an open roller, and the mixture was heated at 170 DEG C for 10 minutes using a hot press to form a sheet. The sheet was post cured at 150 DEG C for 4 hours in an oven, A rubber sample is prepared.

The thus-prepared vulcanized rubber sheet was subjected to cutting with JIS No. 2, which was cut. 6, the dipping test is carried out according to the JIS K6258 process. That is, the immersion test was conducted by using a mixed solution (50 ml + 50 ml, hereinafter referred to as R-407C system) or a mixed solution of R-407c + -22 system) and the test piece are placed in a pressure vessel and held at 125 ° C or 150 ° C for 22 hours to carry out the immersion test. The temperatures used in the present invention and the comparative examples are shown in Tables 1 to 7.

After completion of the immersion, the volume, weight, hardness and tensile strength of the vulcanized rubber due to the total acidity and immersion of the oil were observed, and the state of the test piece after the immersion (degree of foaming and swelling) was observed. Respectively.

The total acid number is measured according to the process of JIS K3504. The change in volume due to immersion is calculated according to JIS K6258 for the weight and specific gravity before and after immersion of each sample piece. The change in hardness and tensile strength in the immersion test is calculated from the measurement results according to JIS K6253 and K6251 processes. Visually observe the condition of freezer oil after immersion.

The criteria are as follows.

A: transparent

B: slightly cloudy

C: fairly cloudy

The state of the test piece after immersion is visually observed, and the result is compared with the state before immersion, and the evaluation is carried out according to the following criteria.

A: No announcement or expansion

B: No foaming, but slight expansion

C: There is little foaming and swelling

D: Foaming and swelling are evident

Abbreviation:

NHBR-1: nitrile content: 44%, iodine value: 10%, Mooney viscosity: 85

NHBR-2: nitrile content: 44%, iodine value: 25%, Mooney viscosity: 78

BFGE-p-tert-butylphenyl glycidyl ether, epoxy equivalent: 226, molecular weight: 206, specific gravity: 1.03

EHGE: 2-ethylhexyl glycidyl ether, epoxy equivalent: 186, molecular weight: 186, specific gravity: 0.90

TMP: trimethylolpropane trimethacrylate

Peroxide-1: Dicumyl peroxide

Peroxide 2:?,? '- bis (t-butylperoxy-m-isopropyl) benzene

Peroxide-3: benzoyl peroxide

ECC: 1,2-epoxycyclohexane, epoxy equivalent: 98, molecular weight: 98, specific gravity: 0.97

AGE: allyl glycidyl ether, epoxy equivalent: 117, molecular weight: 117, specific gravity: 0.97

RGE: a mixture of dodecyl glycidyl ether and tridecyl glycidyl ether (1: 1), epoxy equivalent: 282, average molecular weight: 249, specific gravity: 0.91

PGE: phenyl glycidyl ether, epoxy equivalent: 154, molecular weight: 154, specific gravity: 1.11

PGPEOE: phenylglycidylpenta (ethyleneoxy) ether, epoxy equivalent: 405, molecular weight: 370, specific gravity: 1.12

BFAGE: biphenyl A diglycidyl ether, epoxy equivalent: 189, molecular weight: 380, specific gravity: 1.17

EB: 1,2-epoxybutane, epoxy dimer: 72, molecular weight: 72, specific gravity: 0.83

NBR: Nitrile content: 43%, Mooney viscosity: 85

CR: non-yellowing type, Mooney viscosity: 42 to 51

EPDM: EPDM containing ethylidene norbornane, propylene content: 43%, Mooney viscosity: 45

CIPE: chlorinated polyethylene, chlorine content: 35%, Mooney viscosity: 50

Liquid NBR: Nipol 1312

Anti-aging agent: 4,4'-bis (?,? - dimethylbenzyl) diphenylamine

Process oil: Aromatic hydrocarbon oils

Other than the abbreviations are the same as those shown in this specification.

As apparent from the results shown in the above table, according to the present invention, the vulcanized rubber composition containing a specific epoxy compound and / or the compound (I) The vulcanized rubber composition is hardly deteriorated and exhibits resistance to freon and freezer oil that is superior to the vulcanized rubber composition containing no such compound.

That is, according to the present invention, there is provided a vulcanized rubber composition exhibiting excellent resistance to freon and refrigerator oil without substantially accelerating deterioration of refrigerator oil such as hydrolysis of ester oil. Further, the effect of the present invention is that, because the composition of the present invention has a lower degree of deterioration of refrigerating machine oil as compared with the conventional vulcanized rubber composition, particularly, the refrigerating machine oil, which is a factor preventing the application of the alternative freon to new freon and freezer Considering the fact that there is no rubber with sufficient resistance in the prior art, it is remarkable.

Claims (24)

A rubber composition comprising at least one nitrile group-containing rubber, chloroprene rubber, ethylene propylene rubber and a monofunctional epoxy compound as a base material, wherein the composition is at least one of freon oil and / or refrigerator oil. A rubber composition comprising at least one nitrile group-containing rubber, chloroprene rubber, ethylene propylene rubber and glycidyl ether-type epoxy compound as a base material, and at least one freon and / or refrigerator oil. A rubber composition comprising at least one nitrile group-containing rubber, chloroprene rubber, ethylene-propylene rubber and monofunctional glycidyl ether-type epoxy compound as a base material, in the case of using freon and / or refrigerator oil. The rubber composition according to claim 1, 2 or 3, wherein the epoxy compound has an alkyl group and / or an alkenyl group. The rubber composition according to any one of claims 1, 2 and 3, wherein the epoxy compound has an epoxy equivalent of 100 or more. The rubber composition according to claim 1, 2 or 3, wherein the epoxy compound is used in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the rubber. The rubber composition according to claim 1, 2 or 3, further comprising a compound represented by formula (I) (compound (I)). (Wherein R ¹ is a hydrogen atom or an alkyl group, R ² is an alkyl group or a phenyl group, R ³ is an alkyl group, an alkoxy group or an alkenyloxy group, and n is 1 or 2) The rubber composition according to claim 7, wherein R ¹ is an isopropyl group or a sec-butyl group, R ² is a methyl group, R ³ is an epoxy group or -OC ₁₈ H ₃₅ and n is 1. The rubber composition according to claim 7, wherein the compound (I) is used in an amount of 0.01 to 20.0 parts by weight based on 100 parts by weight of the rubber. A rubber composition according to any one of claims 1, 2 or 3, characterized in that it comprises a nitrile-containing rubber The rubber composition according to claim 10, wherein the nitrile-containing rubber is a hydrogenated nitrile rubber. The rubber composition according to claim 1, 2 or 3, wherein the rubber is crosslinked with a peroxide. The rubber composition according to any one of claims 1, 2, and 3, further comprising a liquid nitrile rubber in an amount of 30 parts by weight or less based on 100 parts by weight of the solid rubber contained in the composition. (I), at least one nitrile group-containing rubber, chloroprene rubber and ethylene propylene rubber as the base, and a compound represented by the formula (I) (Wherein R ¹ is a hydrogen atom or an alkyl group, R ² is an alkyl group or a phenyl group, R ³ is an alkyl group, an alkoxy group or an alkenyloxy group, and n is 1 or 2). The rubber composition according to claim 14, wherein R ¹ is an isopropyl group or a sec-butyl group, R ² is a methyl group, R ³ is an epoxy group or -OC ₁₈ H ₃₅ and n is 1. The rubber composition according to claim 14, wherein the compound (I) is used in an amount of 0.01 to 20.0 parts by weight based on 100 parts by weight of the rubber. The rubber composition according to claim 14, comprising a nitrile-containing rubber. The rubber composition according to claim 17, wherein the nitrile-containing rubber is a hydrogenated nitrile rubber. The rubber composition according to claim 14, wherein the rubber is crosslinked with a peroxide. The rubber composition according to claim 14, further comprising a liquid nitrile rubber in an amount of 30 parts by weight or less based on 100 parts by weight of the solid rubber contained in the composition. A molded article formed from a rubber composition comprising at least one nitrile group-containing rubber, chloroprene rubber and ethylene propylene rubber and a monofunctional epoxy compound, A molded article formed from a rubber composition comprising at least one nitrile group-containing rubber, chloroprene rubber, and ethylene propylene rubber and a glycidyl ether-type epoxy compound as a base material. A molded article formed from a rubber composition comprising at least one nitrile group-containing rubber, chloroprene rubber and ethylene propylene rubber as a base material and a monofunctional glycidyl ether type epoxy compound. (I), at least one nitrile group-containing rubber, chloroprene rubber and ethylene propylene rubber as the base, and a compound represented by the formula (I) (Wherein R ¹ is a hydrogen atom or an alkyl group, R ² is an alkyl group or a phenyl group, R ³ is an alkyl group, an alkoxy group or an alkenyloxy group, and n is 1 or 2).