KR100396015B1 - Vulcanized rubber composition - Google Patents

Abstract

The present invention provides at least one base rubber selected from the group consisting of nitrile rubbers and hydrogenated nitrile rubbers, monofunctional epoxy compounds, and the following 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, n is 1 or 2),

It is to provide a rubber composition for freon and / or freezer oil.

Description

Vulcanized Rubber Composition {VULCANIZED RUBBER COMPOSITION}

The present invention relates to vulcanized rubber compositions and their molded articles for use in the presence of freon and / or freezer oils.

At present, ozone layer destruction is a serious problem, and it is determined that some freon gas that destroys ozone will be disposed of in a few years. For this reason, Freon gas used as a coolant for refrigerators and air conditioners is CFC (Freon consisting of three elements of C, F and Cl) such as R-11 (CCl ₃ F) and R-12 (CCl ₂ F ₂ ). From HCFC (Freon consisting of four elements of C, H, Cl and F) such as R-22 (CHClF ₂ ) and R-123 (CHClFCClF ₂ ), R-134a (CH ₂ FCF ₃ ), R-407c (HFC (freon consisting of three elements of C, H and F; ozone depletion rate: 0)) such as CH ₂ F ₂ / CF ₃ CHF ₂ / CH ₂ FCF ₃ mixture (23/25/52 wt%)) Began to change. In response, the refrigeration oil (lubricating oil of a refrigerator) also used is changing from the mineral oil used in combination with the conventional Freon to oils, such as ester type and polyalkylene glycol.

Following this replacement of coolant and freezer oil, rubber products suitable for such alternatives have also been desired. Conventionally used fluoroelastomers are corroded with fresh Freon R-134a, and chloroprene rubber also promotes hydrolysis of ester oils to deteriorate freezer oil. Accordingly, vulcanized rubber compositions made of nitrile rubber or chlorinated polyethylene have been studied as rubbers for new freons.

For example, JP-A-3-250037 discloses a vulcanized rubber composition containing nitrile rubber, chlorinated polyethylene, and an organic peroxide, while JP-A-5-140334 discloses chlorinated rubber (polychlorinated chlorine, chloroprene). Rubber, etc.) and nitrile-based rubber, and JP-A-6-128415 discloses a rubber compound composition in which an organic peroxide is added to a mixture of nitrile-based rubber and chlorinated ethylene-propylene copolymer rubber. I'm proposing.

However, when vulcanized rubber compositions containing chlorinated rubber are used in refrigerator oil, chlorine as these components acts as a catalyst to promote hydrolysis of the refrigerator oil, thereby causing a problem of decreasing the viscosity and degrading lubricity. This tendency becomes particularly remarkable when freon coexists or when refrigeration oil is ester oil. In addition, JP-A-5-140334 discloses that the vulcanized rubber composition contains metal oxides, metal hydroxides, metal soaps, and the like, but these metal compounds further promote hydrolysis of ester oils.

Further, in JP-B-5-17930, JP-A-5-65369 discloses a vulcanized rubber composition for 0-ring molded article in which 10 to 150 parts by weight of carbon black is added to 100 parts by weight of hydrogenated nitrile rubber. 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.)), but the vulcanized rubber compositions obtained by these techniques are formulated for freon and freezer oils. It was not always satisfactory in view of the resistant cotton and the heat screen of the refrigeration oil.

It is an object of the present invention to provide a vulcanized rubber composition which hardly promotes deterioration of refrigeration oil (for example, hydrolysis of ester oil) and is excellent in resistance to freon and refrigeration oil.

By blending a specific epoxy compound with a specific rubber composition, the present inventors can obtain a vulcanized rubber composition having significantly improved resistance to freon and freezer oil, including little hydrolysis of the ester oil, including hydrolysis of ester oil. I found that.

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

In particular, according to the present invention, it consists of at least one base rubber selected from the group consisting of nitrile group-containing rubber, chloroprene rubber and ethylene propylene rubber, in which a monofunctional epoxy compound is contained, freon and // Or it provides a rubber composition for refrigerator oil.

In addition, according to the present invention, it is composed of at least one base rubber selected from the group consisting of nitrile group-containing rubber, chloroprene rubber and ethylene propylene rubber, in which a glycidyl ether type epoxy compound is contained, freon and / or Provided is a rubber composition for refrigerator oil.

Moreover, according to this invention, it consists of at least 1 sort (s) of base rubber chosen from the group which consists of a nitrile-group containing rubber, a chloroprene rubber, and ethylene propylene rubber, In it, the following formula (I):

A freon containing a compound represented by (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, n is 1 or 2) and And / or rubber compositions for refrigeration oils.

Other objects and advantages of the present invention will become apparent from the following description.

As used herein, "nitrile group-containing rubber" includes various forms of nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), and modified nitrile rubber (e.g., carboxylated nitrile rubber (CNBR)), Sometimes this is also called "nitrile rubber". The nitrile rubber used in the present invention is not particularly limited in terms of nitrile content, hydrogenation rate, molecular weight, and Mooney viscosity, and can be used in combination of a plurality of nitrile rubbers, hydrogenated nitrile rubbers and / or modified nitrile rubbers.

Moreover, as the "chloroprene rubber (CR)" used here, all forms of 2-chlorobutadiene type rubber are mentioned, CR is divided into yellowing type, yellowing type, and high crystalline type, and in this invention, Although any of may be used, it is preferable to use CR of an unmodified form. Using the non-yellowing CR, the deterioration of the refrigeration oil is much more effectively suppressed than with other forms of CR.

In addition, "ethylene propylene rubber" (EP, EPDM) means a rubber product mainly consisting of a copolymer of ethylene and propylene and containing a small amount of diene component in some cases. According to the present invention, it is preferable to use, as the diene component, EPDM containing dicyclopentadiene, ethylidene norbornene or 1,4-hexadiene, especially ethylidene norbornene. By using this type of EPDM, the resistance to vulcanized rubber compositions to freon or freezer oil can be improved more efficiently.

As the raw material rubber of the present invention, a mixture of two or more kinds of the above-mentioned rubbers can be used, and various known rubbers other than the above-mentioned rubbers can 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), silicone rubber (Q), fluorine Lean rubber (F), acrylic rubber (ACM), epichlorohydrin rubber (CO), chlorosulfonate polyethylene (CSM), chlorinated polyethylene (CM), and the like. It is not limited to. However, according to the present invention, the total amount of nitrile rubber, chloroprene rubber and ethylene propylene rubber is preferably 40 to the total rubber (ie, the weight of the material rubber after excluding the epoxy compound, the vulcanizing agent, the filler, etc. from the rubber composition). It is at least 50% by weight, more preferably at least 50% by weight, most preferably at least 80% by weight.

According to the present invention, it is particularly preferable to use hydrogenated nitrile rubber. When hydrogenated nitrile rubber is used, the vulcanized rubber composition becomes resistant to freon and freezer oil, and can control the deterioration of the freezer oil to an extremely low level. Hydrogenated nitrile rubber (hereinafter referred to as "HNBR") includes "Zetpol" (trade name) manufactured by Nippon Zeon Co., Ltd. and "Therban" (trade name) manufactured by Bayer. As the center value, HNBR is preferably an iodide of 50% or less, more preferably 3 to 40%, and most preferably 8 to 30%. Resistance to freon and refrigeration oil can be increased when HNBR with a central iodine value of 50% or less (high hydrogenation rate) is used, and rubber elasticity at low temperatures can be preserved by using rubber having a low hydrogenation rate. Therefore, the center value of the nitrile content of HNBR is preferably approximately 15 to 60%, more preferably 30 to 55%, most preferably 40 to 50%. In addition, resistance to freon and freezer 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 less than 60%, in particular less than 50%. Can be. In addition, the Mooney viscosity (hereinafter, referred to as "Mooney viscosity") as the center value of ML _{1 + 4} (100 ° C) is preferably 55 to 100, more preferably 65 to 95, and most preferably 75 to 90 to be. When using HNBR having a Mooney viscosity in the above range, the vulcanized rubber composition can maintain high resistance to freon and refrigeration oil, and also excellent flexibility and low temperature resistance.

You may use combining liquid nitrile rubber (henceforth "liquid NBR") as a raw material of the vulcanized rubber composition of this invention. As used herein, "liquid NBR" means a nitrile rubber showing fluidity at room temperature, and a rubber not showing fluidity at room temperature is referred to as "solid rubber" below. Here, room temperature means 0-50 degreeC, especially 15-35 degreeC. Liquid NBRs include "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, by adding 100 parts by weight of liquid NBR to 50 parts by weight of solid rubber, particularly 30 parts by weight or less, the hardness of the vulcanized rubber composition can be reduced without impairing the effects of the present invention. In addition, the resistance to freon and refrigeration oil can be further improved according to the conditions of use of the vulcanized rubber composition. In particular, this effect is remarkable when the solid rubber is mainly HNBR. The liquid NBR is preferably used in an amount of about 50 parts by weight or less, more preferably 30 parts by weight or less and most preferably 20 parts by weight or less based on 100 parts by weight of HNBR.

Vulcanized rubber is well known per se and can be obtained by crosslinking uncrosslinked rubber with peroxide. The peroxide used in the crosslinking is not particularly limited, but for example, di-t-butylperoxide, dicumylperoxide, t-butylcumyl peroxide, 1,1-di (t-butylperoxy) -3 , 3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexine-3 , 1,3-di (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyisopropylcarbonate, n-butyl-4, 4-di (t-butyl peroxy) valerate, (alpha), (alpha) '-bis (t-butyl peroxy m-isopropyl) benzene, benzoyl peroxide, etc. are mentioned. Peroxide may be used by mixing carbon black, calcium carbonate, rubber or the like in advance. The peroxide is preferably used in an amount of about 0.5 to 30 parts by weight, more preferably 1 to 15 parts by weight with respect to 100 parts by weight of rubber, and when the amount of peroxide is less than 0.5 parts by weight, the vulcanized rubber composition for freon and freezer oil There exists a possibility that resistance may not fully improve, and when it exceeds 30 weight part, a vulcanized rubber composition may harden | cure. Apart from the above, chloroprene rubber or carboxylated nitrile rubber may be crosslinked using metal oxides such as magnesium oxide and zinc oxide, or metal peroxides. For example, magnesium oxide may be used in an amount of preferably about 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, and most preferably 2 to 6 parts by weight based on 100 parts by weight of chloroprene rubber. In addition, rubbers other than HNBR having a hydrogenation rate of 100% can be crosslinked using sulfur and / or a vulcanization accelerator. The above-mentioned crosslinking agents include various crosslinking aids such as triallyl isocyanurate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, polybutadiene, polyfunctional methacrylate monomer, and polyhydric alcohol (meth) acrylate; Or thiuram type vulcanization accelerators such as tetramethyl thiuram disulfide (TT), tetraethyl thiuram disulfide (TET), tetrabutyl thiuram disulfide (TBT), and dibenzothiazyl disulfide and 2-mer Thiazole type accelerators such as captobenzothiazole, guanidine type accelerators such as trimethylthioure and 1,3-diphenylguanidine, sulfenamide type accelerators of N-cyclohexyl-2-benzothiazolyl sulfenamide, and zinc dimethyldithiocarba Dithiocarbamate type | mold promoters, such as a mate and diethyldithio carbamate, can be mixed with xanthogenate type | mold promoters, such as zinc butyl xanthogenate, hexamethylenetetramine, and n-butylaldehyde aniline.

Molding can be performed by using an injection molding machine, a compression molding machine, a vulcanization press, or the like, for example, by crosslinking at about 150 to 250 ° C. for 3 to 60 minutes, and post-curing at about 120 to 200 ° C. in an oven. 1 to 24 hours.

A feature of the present invention lies in that the vulcanized rubber composition described above contains a specific epoxy compound or a specific aluminum complex. By doing so, it is possible to obtain a vulcanized rubber composition exhibiting excellent resistance to freon and freezer oil, with little acceleration of refrigeration oil deterioration. In particular, when used in ester refrigerator oil, hydrolysis of the refrigerator oil is suppressed. The degree of degradation due to hydrolysis is evaluated by the total acid number of the oil, and as the degradation progresses, the total acid number becomes larger. In the present invention, the increase in total arithmetic is suppressed. In addition, the vulcanized rubber composition of the present invention in which a specific epoxy compound is blended is superior in water resistance, solvent resistance, electrical properties, mechanical properties, adhesive properties and heat resistance as compared with vulcanized rubber compositions containing no epoxy compound.

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

Examples of such epoxy compounds include monofunctional epoxy compounds such as epoxy butane, epoxy butene, epoxy cyclohexane, epoxy norbornane, epoxy hexene, epoxy octene, glycidol and glycidyl phthalimide; Glycols, such as neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether, polyethyleneglycol diglycidyl ether, glycerol polyglycidyl ether, and triglycidyl tris (2-hydroxyethyl) isocyanurate Cydyl 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, Methylethylcyclohexyl glycidyl ether, 2-ethylhexyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, isocyl glycidyl ether, phenylglycidyl ether, toluyl glycidyl Ether, benzyl glycidyl ether, p-tert-butylphenyl glycidyl ether, dibromophenyl glycidyl ether, naphthyl glycidyl ether, lauryl glycidyl ether, allyl glycidyl ether, isopro Monofunctional glycidyl ether type epoxy compounds such as phenyl glycidyl ether, butenyl glycidyl ether, phenyl glycidyl penta (ethyleneoxy) ether and lauryl glycidyl pentadeca (ethylene oxy) ether Can be used in the present invention Examples of the epoxy compound which can be used are not limited to the epoxy compounds exemplified above. These epoxy compounds can be used individually or as a mixture of 2 or more types.

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

In addition, the epoxy compound preferably contains an alkyl group and / or an alkenyl group. When using an epoxy compound that does not contain an alkyl group or an alkenyl group, it is possible to suppress the increase in the total acid number of the refrigeration oil, but colloidal precipitates may be formed depending on the type and use conditions of the refrigeration oil. The epoxy compound preferably has an epoxy sugar (the number of grams of the compound containing 1 g equivalent of epoxy group) of 100 or more, particularly 170 or more. If the epoxy equivalent is too small, colloidal precipitates may be formed depending on the type of refrigeration oil and the conditions of use. In addition, an epoxy compound having a branched alkyl and / or alkenyl group, such as an allyl group and a vinyl group, may be used, and an epoxy compound having an alkyl group having 7 to 15 carbon atoms is particularly preferable. By using such a compound, the increase in the total acid number of the refrigeration oil is more effectively suppressed, and the resistance of the vulcanized rubber composition to freon and the refrigeration oil is improved at the same time. When the molecular weight of the epoxy compound is 1,000 or less, especially 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, little discharge occurs.

According to the present invention, the epoxy compound is used in an amount of preferably about 0.1 to 50 parts by weight, more preferably 1 to 40 parts by weight, and most preferably 3 to 30 parts by weight with respect to 100 parts by weight of rubber. When the amount of the epoxy compound is less than 0.1 part by weight, the reduction of the total acid number of the refrigeration oil and the improvement of the resistance of the vulcanized rubber composition to freon and the refrigeration oil are insufficient. This becomes insufficient.

Specific aluminum complexes that can be used in the present invention are compounds represented by the following formula (hereinafter referred to as "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, n is 1 or 2).

Examples of compound (I) include mono- (oleyl-3-oxobutanoate-O ¹ , O ³ ) -bis- (2-propanolate) -aluminum (III) (hereinafter referred to as "OBPA") , Aluminum (III) di-sec-butoxide ethyl acetoacetate (hereinafter referred to as "ABEA"), aluminum (III) diisopropoxide ethyl acetoacetate (hereinafter referred to as "AIEA"), bis- (oleic) Yl-3-oxobutanoate-O ¹ , O ³ ) -mono- (2-propanolate) -aluminum (III), mono- (stearyl-3-oxobutanoate-O ¹ , O ³ )- Bis-hydroxy-aluminum (III), mono (ethyl-3-oxobutanoate-O ¹ , O ³ ) -bis-hydroxy-aluminum (III), mono- (ethoxy-3-oxobutanoate -O ¹ , O ³ ) -bis-hydroxy-aluminum (III), mono (ethoxy-3-oxobutanoate-O ¹ , O ³ ) -bis- (2-propanolate) -aluminum (III) , Mono- (propoxy-3-oxobutanoate-O ¹ , O ³ ) -bis- (2-propanolate) -aluminum (III), mono- (oleyl-3-oxo-3-fe Carbonyl propionate -O ^1, O ³⁾ bis (2-propanol rate) - aluminum (Ⅲ) and the like, compound (I) is not limited to these compounds. Compound (I) may be used alone or as a mixture of two or more thereof. However, in compound (I), R ¹ is preferably 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 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, in particular, 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 = methyl group , R ³ = ethoxy group, n = 1) or AIEA (R ¹ = isopropyl group, R ² = methyl group, R ³ = ethoxy group, n = 1) is selected as compound (I), The resistance of the rubber composition is further remarkably improved, and the increase in the total acid number of the refrigeration oil is more strongly suppressed.

The chemical formula of the above-mentioned more preferable example of compound (I) is as follows.

According to the present invention, the compound (I) is preferably about 0.01 to 20.0 parts by weight, more preferably about 0.05 to 10.0 parts by weight, and most preferably about 0.1 to 5.0 parts by weight based on 100 parts by weight of rubber. Used as 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 freon and refrigeration oil and the decrease of the total acid number of the refrigeration oil are insufficient. Do not.

In a more preferable aspect of the present invention, the above-mentioned epoxy compound and compound (I) are used in combination in the amounts described above. By this combination use, the resistance of the rubber composition to freon and freezer oil is significantly improved, and the total arithmetic output of the freezer oil is reduced to a lower level.

The vulcanized rubber composition of the present invention containing a specific epoxy compound and / or compound (I) can suppress deterioration of the refrigeration oil. In particular, when used in the presence of an ester type refrigeration oil, the composition of the present invention exhibits the advantage that the total acid number of the ester oil becomes small as compared with conventional vulcanized rubber compositions containing no epoxy compound and compound (I). In addition, the vulcanized rubber composition of the present invention is HFC (for example, R-134a, R-32, R-125, R-143a, R-407c, R-404A, R-507), HCFC (for example , Freon in various forms such as R-22, R-123) and CFC (eg, R-11, R-12); Refrigerator oils of various types such as ester oils, polyalkylene glycol oils, ether oils, polycarbonate oils, paraffinic mineral oils, naphthenic mineral oils, alkylbenzenes, and poly-α-olefins; And excellent resistance to these mixtures.

This effect is particularly remarkable for the epoxy compound-containing vulcanized rubber composition of the present invention. In addition, this type of composition of the present invention is excellent in water resistance, solvent resistance, electrical properties, mechanical properties, adhesive properties and heat resistance compared with other vulcanized rubber compositions containing no epoxy compound.

Although the present invention is not limited to a specific theory, the inactivation of impurities contained in the nitrile-based raw material rubber by the epoxy compound and / or compound (I) can be considered as a reason for achieving the effect of the present invention. Nitrile rubbers contain a small amount of soaps, coagulants, iron-containing metal catalysts, cobalt-containing metal catalysts, etc., which remain after polymerization and hydrogenation.The infiltration of these impurities into the freezer oil may cause deterioration of the freezer oil or Suppression of crosslinking When crosslinking is inhibited, the resistance of the vulcanized rubber composition to freon and freezer oil is reduced. On the other hand, in the case of vulcanized rubber compositions in which epoxy compounds and / or compounds (I) are added according to the invention, these impurities appear to be inactivated through reaction with epoxy compounds or aluminum complexes, i.e. compound (I). The rubber composition is completely crosslinked, exhibits high resistance to freon and refrigeration oil, and deterioration of the refrigeration oil does not occur since such impurities do not penetrate into the refrigeration oil. Among the epoxy compounds, monofunctional epoxy compounds or glycidyl ether type epoxy compounds are the most efficient, because these compounds have terminal groups other than epoxy groups or are stable in the molecule and at the same time relatively high polar ether bonds. This is because the reaction product of the epoxy group and the impurity is easily trapped into the nitrile rubber through the terminal and the intramolecular portion. In particular, when the epoxy compound described above has an alkyl group (particularly a branched alkyl group) or an alkenyl group, or has an epoxy equivalent of 170 or more, the reaction product of the epoxy group and impurities can be easily trapped into the nitrile rubber through hydrocarbon radicals or the like. do. In addition, when refrigeration oil, especially ester type refrigeration oil, deteriorates, an acid such as carboxylic acid is formed, and the formed acid further promotes deterioration of the refrigeration oil. However, it is believed that when the vulcanized rubber composition of the present invention is used, the epoxy group reacts with the acid to inactivate the acid, thereby preventing deterioration of the refrigeration oil.

In addition to the above-mentioned components, the vulcanized rubber composition of the present invention has a SAF (particle diameter; about 11 to 19 nm), ISAF (particle diameter; about 20 to 25 nm), HAF (particle diameter; about 26-30 nm), FF (particle diameter; about 31 to 39 nm ), FEF (particle size; about 40 to 48 nm), GPF (particle size; about 49 to 60 nm), SRF (particle size; about 61 to 100 nm), FT (particle size; about 101 to 200 nm), MT (particle size; about 201 to 500 nm It may further contain carbon black, such as). In this regard, each of the SAF to MT represents a particle size classification in the preparation method. Moreover, antioxidants, such as an ozone deterioration inhibitor and antioxidant, can be mixed. For example, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, phenyl-1-naphthylamine, alkylated diphenylamine, p- (p-toluenesulfonylamide) Diphenylamine, N, N'-di-2-naphthyl-p-phenylenediamine, α-methylbenzylphenol, N, N'-diphenyl-p-phenylenediamine, 2,6-di-tert- Butyl-4-methylphenol, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, 4,4'-dithiobis (3-methyl-6-tert-butylphenol), 2,2,4 -Trimethyl-1,2-dihydroquinoline polymer, reaction product of diphenylamine and acetone, 2,5-di-tert-butylhydroquinone, 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, 2 Zinc salt of mercaptobenzimidazole, nickel dibutyldithiocarbamate, tributylthiourea, tris (nonylphenyl) phosphate, dilaurylthiodipropionate, and the like.

In addition, an adjuvant for peroxide crosslinking such as propane trimethacrylate, a polyfunctional methacrylate monomer, and a polyhydric alcohol (meth) acrylate may be mixed with triallyl isocyanurate, ethylene glycol dimethacrylate, and trimethyl.

In addition to the above components, the vulcanized rubber composition of the present invention may contain various additives used in conventional rubber composition applications, for example, reinforcing materials such as microsilica; Fillers such as tellk, clay, graphite, calcium silicate, calcium carbonate and barium sulfate; Fiber for reinforcing such as aramid fiber, carbon fiber, glass fiber, tackifier, plasticizer, colorant, processing aid and the like.

The manufacturing method of the vulcanized rubber composition of this invention is not specifically limited, It can manufacture by the rubber kneading vulcanization method conventionally used. For example, essential ingredients are kneaded using an open roller, Banbury mixer, pressurized kneader, extruder, etc., and then vulcanized in a desired shape.

The vulcanized rubber composition of the present invention hardly promotes deterioration of the refrigeration oil while showing excellent resistance to freon and freezer oil. Therefore, the vulcanized rubber composition of the present invention is a molding material for rubber parts (for example, 0-rings, sealing sleeves, packings, hoses, tubes) used in compressors of refrigerators, air conditioners and the like, in particular, compressors of freezers. Suitable for use as In addition, the vulcanized rubber composition of the present invention has excellent water resistance, solvent resistance, electrical properties, mechanical properties, adhesion properties and heat resistance compared to 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 molded articles obtained from the vulcanized rubber compositions described above, such as 0-rings, sealing sleeves, packings, hoses, tubes and the like. These vulcanizates rarely promote deterioration of refrigeration oils, and also HFCs (e.g. R-134a, R-32, R-125, R-143a, R-407c, R-404A, R-507), HCFC Various freons such as (eg, R-22, R-123) and CFR (eg, R-11, R-12); Refrigerator oils of various types such as ester oils, polyalkylene glycol oils, ether oils, polycarbonate oils, paraffinic mineral oils, naphthenic mineral oils, alkylbenzenes, and poly-α-olefins; And good resistance to these mixtures. The vulcanized molded article of the present invention is particularly advantageous when used in refrigeration machines such as refrigerators and air conditioners using ester oils which are easily hydrolyzed.

Example

Hereinafter, the present invention will be described in detail through examples.

Rubber samples of various compositions as shown in Tables 1 to 7 were prepared, and immersion tests using Freon and refrigerator oil were performed. In this regard, the units of each compounding agent 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 ° C. for 10 minutes using a hot press to form a sheet, and the sheet was post-cured at 150 ° C. for 4 hours in an oven, respectively. A rubber sample was prepared.

The immersion test was performed according to JIS K6258 process using three dumbbell-type test pieces of JIS No. 6 cut | disconnected from the vulcanized rubber sheet manufactured in this way. That is, the immersion test is a mixed solution of R-407C + ether oil (50 mL + 50 mL, hereinafter referred to as "R-407C system") or a mixed solution of R-22 + mineral oil (50 mL + 50 mL, hereinafter, The immersion test was carried out by placing the specimen and the test piece in a pressure vessel and holding it at 125 ° C. or 150 ° C. for 22 hours. The temperatures used in the present invention and comparative examples are shown in Tables 1-7.

After the immersion, the volume, weight, hardness and tensile strength of the vulcanized rubber due to the total arithmetic and immersion of the oil and the state of the specimen (foaming and swelling) after immersion were observed. Shown in

The total arithmetic value was measured according to the process of JIS K3504, and the volume change by dipping was calculated according to JIS K6258 with respect to the weight and specific gravity before and after dipping of each sample piece. The change in hardness and tensile strength during the immersion test was calculated from the measurement results performed according to the procedures of JIS K6253 and K6251. After immersion, the state of the refrigeration oil was visually observed.

The criteria are as follows.

A: transparent

B: slightly turbid

C: quite cloudy

After immersion, the state of the test piece is visually observed, the result is compared with the state before immersion, and evaluation is performed according to the following criteria.

A: No foaming and expansion

B: No foaming but slight expansion

C: slight foaming and expansion

D: Foaming and expansion are apparent

Table 1

(Immersion test result)

TABLE 2

(Immersion test result)

TABLE 3

(Immersion test result)

Table 4

(Immersion test result)

Table 5

(Immersion test result)

Table 6

(Immersion test result)

TABLE 7

Abbreviated name:

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: α, α'-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: allylglycidyl ether, epoxy equivalent: 117, molecular weight: 117, specific gravity: 0.97

RGE: mixture of dodecyl glycidyl ether and tridecylglycidyl ether (1.1), epoxy equivalent: 282, average molecular weight: 249, specific gravity: 0.91

PGE: Phenylglycidyl ether, Epoxy equivalent: 154, Molecular weight: 154, Specific gravity: 1.11

PGPEOE: Phenylglycidyl penta (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 equivalent: 72, molecular weight: 72, specific gravity: 0.83

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

CR: Sulfur free deformation, 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

Antioxidant: 4,4'-bis (α, α-dimethylbenzyl) diphenylamine

Process oil: aromatic hydrocarbon oil

Other than the above abbreviations, they are the same as those shown on the present specification.

As is 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 compound (I), compared with other vulcanized rubber compositions containing no such compound, It hardly deteriorates and exhibits resistance to freon and freezer oils, superior to vulcanized rubber compositions that do not contain these compounds.

That is, according to the present invention, there is provided a vulcanized rubber composition which hardly promotes deterioration of refrigeration oil such as hydrolysis of ester oil, and exhibits excellent resistance to freon and refrigeration oil. In addition, the effect of the present invention is that the composition of the present invention has a lower degree of deterioration of the refrigeration oil compared with the conventional vulcanized rubber composition, and therefore, particularly with respect to the refrigeration oil, which is a factor that prevents the application of a replacement freon to a new freon and a freezer. Considering the fact that rubber with sufficient resistance was not in the prior art, it is remarkable.

As mentioned above, although this invention was demonstrated in detail with reference to the specific embodiment, it is clear for those skilled in the art that various changes and correction of this invention are possible, without deviating from the mind and range of this invention.

Claims (13)

Rubber for freon and / or freezer oil, characterized by containing 0.1 to 50 parts by weight of a monofunctional epoxy compound with respect to 100 parts by weight of at least one base rubber selected from the group consisting of nitrile rubber and hydrogenated nitrile rubber. Composition. The rubber composition for freon and / or freezer oil according to claim 1, wherein the monofunctional epoxy compound is a monofunctional glycidyl ether type epoxy compound. The rubber composition according to claim 1 or 2, wherein the epoxy compound has an alkyl group and / or an alkenyl group. The rubber composition according to claim 1 or 2, wherein an epoxy equivalent of the epoxy compound is 100 or more. The compound (compound (I)) according to claim 1 or 2, represented by the following 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, n is 1 or 2, and the rubber composition further comprises . The rubber composition according to claim 5, wherein R ¹ is an isopropyl group or sec-butyl group, R ² is a methyl group, R ³ is an epoxy group, or -OC ₁₈ H ₃₅ , n is 1. The rubber composition according to claim 5, 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 rubber. The rubber composition according to claim 1, wherein a hydrogenated nitrile rubber is used as the base rubber. The rubber composition according to claim 1 or 2, wherein the rubber is crosslinked with a peroxide. The rubber composition according to claim 1 or 2, 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 produced by molding the rubber composition according to claim 1. A molded article produced by molding the rubber composition according to claim 2. A molded article produced by molding the rubber composition according to claim 7.