JP2008106206A - Crosslinkable rubber composition comprising mixture of hydrogenated acrylonitrile-butadiene rubber, isoprene-isobutylene rubber and ethylene-propylene rubber and crosslinked rubber product obtained by crosslinking the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a composition of a mixture of hydrogenated nitrile rubber and butyl rubber, crosslinkable by an alkylphenol-formaldehyde resin without using a halogen compound. <P>SOLUTION: The crosslinkable rubber composition comprises (A) 100 pts. by wt. of the total of 5-95 pts. by wt. of hydrogenated acrylonitrile-butadiene rubber, 95-5 pts. by wt. of isoprene-isobutylene rubber and 0-30 pts. by wt. of ethylene-propylene rubber, (B) 5-25 pts. by wt. of an alkylphenol-formaldehyde resin and (C) 0.3-10 pts. by wt. of an epoxy compound. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composition of a hydrogenated nitrile rubber that is a synthetic rubber, a mixture of isoprene / isobutylene rubber and a hydrogenated nitrile rubber, a mixture of isoprene / isobutylene rubber, ethylene / propylene rubber, and a method for crosslinking the composition, The present invention relates to a crosslinked rubber product obtained by crosslinking a product.

  Hydrogenated nitrile rubber (hereinafter sometimes abbreviated as H-NBR) is a hydrogenated acrylonitrile-butadiene rubber (hereinafter sometimes abbreviated as NBR), which is a synthetic rubber produced by copolymerization of acrylonitrile and butadiene. It is a well-known synthetic rubber marketed under the trade name such as Zettopol from Nippon Zeon Co., Ltd. or Terban from LANXESS.

  About the method of hydrogenation and the outline | summary of rubber | gum, it describes in the nonpatent literature 1, the nonpatent literature 2, the nonpatent literature 3, etc., for example.

  The hydrogenated nitrile rubber has an acrylonitrile content of 17% to 50% and an iodine value (central value) of 4 g / 100 g to 60 g / 100 g. For general purposes, the iodine value (central value) of 4 g / 100 g to 30 g / 100 g Are commercially available.

  Hydrogenated nitrile rubber has excellent heat resistance, high physical strength, chemical stability, low gas permeability, ozone resistance, etc., and is used for toothed belts for automobiles, seals, O-rings, hoses, etc. ing. As the crosslinking method, organic peroxide crosslinking and sulfur crosslinking are generally used.

  Hydrogenated nitrile rubber can be used in a wide range of heat resistance, cold resistance and processability by selecting raw rubber grades with different acrylonitrile contents, based on two methods: organic peroxide crosslinking and sulfur crosslinking. .

  Isoprene / isobutylene rubber (hereinafter sometimes abbreviated as butyl rubber) is produced by copolymerization of isoprene and isobutylene, and has a degree of unsaturation of 0.5 mol% to 3 mol%, and is a known synthetic rubber.

  As crosslinking methods, sulfur crosslinking and resin crosslinking are generally used.

  Cross-linked rubber is excellent in electrical insulation, weather resistance, chemical resistance against acids and ants, anti-vibration, low gas permeability, automotive tube, anti-vibration rubber, curing bag, rubber plug, hose and electric wire It is used for coatings.

  Ethylene / propylene rubber (hereinafter abbreviated as EPDM) is a terpolymer of ethylene, propylene and diene, and diene employed as the third component includes 1.4-hexadiene and ethylidene norbornene. It is a known synthetic rubber.

  As crosslinking methods of EPDM, four methods of sulfur crosslinking, organic peroxide crosslinking, quinoid crosslinking, and resin crosslinking are known [Non-Patent Document 4].

  Cross-linked rubber is widely used for automobiles, architectural gaskets, heat-resistant hoses, rubber plugs, electric wire coatings, and the like.

  It is a common practice for a person skilled in the art to mix (blend) two or more types of rubbers and impart the characteristics of each rubber to the other rubber to produce a rubber product having novel characteristics. That is.

  However, by blending hydrogenated nitrile rubber and butyl rubber, and blending hydrogenated nitrile rubber, butyl rubber, and EPDM, the properties of hydrogenated nitrile rubber can be imparted to butyl rubber, However, imparting the characteristics of butyl rubber has not been performed due to problems related to crosslinking (vulcanization).

  When blending two or more kinds of rubbers, it is necessary that the rubber blended in an arbitrary ratio can be well crosslinked.

  For example, organic peroxide, which is a good crosslinking agent for hydrogenated nitrile rubber, cannot be used because it causes softening and deterioration of butyl rubber. Cross-linking with sulfur or sulfur compounds is a common cross-linking method for hydrogenated nitrile rubber, butyl rubber, and EPDM. However, butyl rubber undergoes reversion at high temperatures to improve heat resistance. It is inappropriate as a vulcanization method.

  Furthermore, when rubber co-crosslinked with a sulfur compound is used as a sealing rubber for aluminum electrolytic capacitors that directly contact aluminum or copper, or as a coating for electric wires, it may lead to dielectric breakdown. Use is undesirable. This breakdown is a phenomenon called a chemical tree.

  No report can be found on a crosslinking method using an alkylphenol-formaldehyde resin (hereinafter abbreviated as resin crosslinking) of hydrogenated nitrile rubber, which is different from the above-described crosslinking method.

  However, acrylonitrile and butadiene, which are raw materials to be hydrogenated, have the following description in “5.5.3 NBR resin vulcanization” of Non-Patent Document 5.

 "NBR resin vulcanization takes longer than TMTD vulcanization. Varying vulcanization speed and physical properties vary depending on NBR type, resin type and blending amount, addition of activator (stannic chloride) and zinc white. In general, the vulcanization rate is slow .... Omitted ... The vulcanization rate is slow, so this vulcanization system is not very important for NBR. "

  Non-patent document 6 also describes that it is necessary to use a chlorine compound in combination with NBR resin crosslinking.

  The contents related to the above techniques are commonly recognized among those skilled in the art.

  From known materials for resin crosslinking of NBR, the resin crosslinking of hydrogenated nitrile rubber has a slow crosslinking speed, and it is necessary to use a chlorine compound such as stannic chloride in order to improve the crosslinking speed. Presumed to be waxy. However, a description of resin crosslinking of hydrogenated nitrile rubber cannot be found from rubber technical books or catalogs of synthetic rubber manufacturers.

  It is used in heat resistant seals or heat resistant O-rings, which are important applications of hydrogenated nitrile rubber. In many of its main applications, the raw material hydrogenated nitrile rubber does not contain halogen, and the crosslinking method uses a crosslinking agent that does not contain halogen, such as organic peroxide crosslinking and low sulfur crosslinking. Thus, it is possible to obtain excellent characteristics.

  However, resin crosslinking using a hydrogenated nitrile rubber chlorine compound is not practical.

  From the technical background of the crosslinking as described above, there is no known method for improving the properties of the crosslinked rubber by mixing a rubber mixed in an arbitrary ratio of hydrogenated nitrile rubber and butyl rubber, or further mixing EPDM. .

  As a specific problem, hydrogenation is an improved method in an atmosphere of 105 ° C to 125 ° C or higher, which is the heat-resistant limit temperature of butyl rubber, in products such as sealing rubbers for aluminum electrolytic capacitors or O-rings that use butyl rubber. It would be highly desirable if normal properties with a high degree of cross-linking could be obtained by mixing rubber mixed at an arbitrary ratio of nitrile rubber and butyl rubber, or further EPDM.

That is, by developing a co-crosslinking method for a rubber mixed with hydrogenated nitrile rubber and butyl rubber in an arbitrary ratio, or a rubber mixed with EPDM, it becomes possible to impart hydrogenated nitrile rubber characteristics to butyl rubber. This means that it becomes possible to impart properties of butyl rubber and EPDM to hydrogenated nitrile rubber.
Journal of Japan Rubber Association, Volume 70 (1997), Page 666, Page 681 Journal of the Japan Rubber Association, Volume 75 (2002), page 207 Journal of the Japan Rubber Association, Volume 79 (2006), Page 33 Rubber Industry Handbook (4th edition), page 302 (issued by the Japan Rubber Association on January 20, 1994) Taiseisha "Crosslinking agent handbook" page 133 Japan Rubber Association "Rubber Industry Handbook (Fourth Edition)" Page 69

  The first object of the invention is to use a mixture of a hydrogenated acrylonitrile rubber (hereinafter sometimes referred to as a hydrogenated nitrile rubber) and butyl rubber, and a hydrogenated nitrile rubber, a mixture of butyl rubber and EPDM without using a halogen compound. It is to provide a novel crosslinkable composition with a formaldehyde resin and a crosslinking method.

  The second object of the present invention is to provide a crosslinked rubber product obtained by crosslinking the composition.

  Furthermore, the third object of the present invention is to provide a crosslinked rubber product excellent in heat resistance, electrical insulation and chemical resistance.

  Furthermore, other objects of the present invention will become more apparent from the following description.

  The object of the present invention is to provide a crosslinkable composition obtained by adding a mixture of hydrogenated nitrile rubber and butyl rubber, a mixture of hydrogenated nitrile rubber, butyl rubber, and EPDM to an alkylphenol-formaldehyde resin and an epoxy compound, and This is achieved by a crosslinked rubber product produced by a crosslinking method. More specifically, a total of 100 parts by weight of alkylphenol / formaldehyde, 5 parts by weight to 95 parts by weight of hydrogenated acrylonitrile / butadiene rubber, 95 parts by weight to 5 parts by weight of butyl rubber, and 0 parts by weight to 30 parts by weight of EPDM. 5 parts by weight to 25 parts by weight of resin, and one epoxy group is added to the skeleton of bisphenol A type epoxy resin, bisphenol F type or AD type epoxy resin, or bisphenol AD type epoxy resin with 2 carbon atoms Bisphenol type epoxy resin, phenol biphenylene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthol modified novolak type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane Multifunctional epoxy resin, cycloaliphatic epoxy resin, polyglycidylamine type epoxy resin, glycidyl ester epoxy of phthalic acid (o-, m-, p-) or hydrophthalic acid (o-, m-, p-) A composition obtained by adding 0.3 to 10 parts by weight of one or more epoxy resins selected from the group consisting of resins, and a crosslinked rubber obtained by crosslinking by a method of crosslinking the composition Achieved by:

  Next, the present invention will be described in more detail.

  The invention provides a composition having heat and oil resistance characteristics while retaining the characteristics of butyl rubber, and blending a small amount of butyl rubber and EPDM with hydrogenated nitrile rubber, thereby Improved cross-linkable heat- and oil-resistant composition with improved rubber kneading process, ie, wrapping of uncrosslinked compound around open roll, which is a disadvantage of hydrogenated nitrile rubber, and improved sheeting properties It is possible to provide a crosslinked rubber product.

  And this invention is achieved by using together an alkylphenol formaldehyde resin and an epoxy compound.

  It is totally unexpected that a mixture of hydrogenated nitrile rubber and butyl rubber, and a mixture of hydrogenated nitrile rubber, butyl rubber and EPDM can be well cross-linked by halogen-free alkylphenol-formaldehyde resins and epoxy resins.

  As a specific example, the following problems are desired as the properties of the sealing rubber of the aluminum electrolytic capacitor.

  (1) Improving the heat resistance temperature of butyl rubber and EPDM by 10 ° C to 50 ° C. (2) Do not use synthetic rubber to which halogen is added. (3) Gas permeability is close to butyl rubber. (4) Composition with a small amount of carbon black used, durometer A hardness and easy blending of about 90 degrees (5) High filling blending is possible, and sheeting characteristics required during molding are good. (6) The crosslinked rubber should have an elongation (%) at break of nearly 100%. (7) Do not use sulfur as a crosslinking agent that may cause metal corrosion.

  The present inventor has found that the above-mentioned problems can be addressed by crosslinking the composition according to the present invention.

  In the present invention, when a mixture of two types of hydrogenated nitrile rubber and butyl rubber is used, it is preferably 10 to 90 parts by weight of hydrogenated nitrile rubber and 90 to 10 parts by weight of butyl rubber, and further EPDM is mixed. In this case, preferably, EPDM is mixed in an amount of 5 parts by weight to 20 parts by weight, that is, out of a total of 100 parts by weight of a mixture of three kinds of rubbers, the amount of EPDM mixed is at most 20 parts by weight.

  Of the total 100 parts by weight of the mixture of the three types of rubber, when the EPDM mixing amount is 30 parts by weight or less, the effect of improving the compound sheeting characteristics, the high filling compounding aid, etc. within the range where the gas permeability is not increased. There is.

  The scope of the present invention does not include halogenated butyl rubber obtained by adding bromine or chlorine to isoprene / isobutylene rubber.

The alkylphenol / formaldehyde resin used in the present invention is not particularly limited, but a compound having a relatively low molecular weight methylol group can be preferably used. For example, as represented by the following formula (1), n is 0 to 10 (wherein R represents an aliphatic alkyl group having 1 to 10 carbon atoms, and R ′ represents —CH ₂ — or —CH ₂ OCH ₂ —. A mixture of low molecular weight compounds represented by Such a compound is commercially available, for example, under the trade name Tacrol 201 (product of Taoka Chemical Co., Ltd.).

  The added alkylphenol-formaldehyde resin is 5 parts by weight to 95 parts by weight of hydrogenated nitrile rubber and 95 parts by weight to 5 parts by weight of butyl rubber, and 5 parts by weight to 95 parts by weight of hydrogenated nitrile rubber and butyl rubber. Of the total 100 parts by weight of 5 parts by weight to 95 parts by weight, 5 parts by weight to 25 parts by weight, preferably 8 parts by weight to 20 parts by weight with respect to 100 parts by weight of the compound meter in which 30 parts by weight or less are replaced with EPDM. Part.

  If the addition amount is less than 5 parts by weight, the intended effect cannot be obtained, and addition of 25 parts by weight or more is not particularly necessary to obtain the intended effect of the present invention, and the addition amount is less than that. A sufficient effect can be obtained.

  The use of a halogenated alkylphenol / formaldehyde resin in which a methylol group portion of the alkylphenol / formaldehyde resin or a halogen such as bromine is substituted on the benzene nucleus is unsuitable for the purpose of the present invention and is not included in the scope of the present invention.

  Next, the epoxy resin used in the present invention refers to one methyl group added to the skeleton of a bisphenol A type epoxy resin, a bisphenol F type or AD type epoxy resin, or a bisphenol AD type epoxy resin. Bisphenol type epoxy resin, phenol biphenylene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthol modified novolak type epoxy resin, dicyclopentadiene type epoxy resin, triphenyl substituted with alkyl group having 2 to 12 carbon atoms Methane type polyfunctional epoxy resin, cycloaliphatic epoxy resin, polyglycidylamine type epoxy resin, glycidyl ester of phthalic acid (o-, m-, p-) or hydrophthalic acid (o-, m-, p-) Epoxy resin Is one or more kinds of epoxy resin selected from the group consisting of.

  If the amount of the epoxy resin used is less than 0.3 parts by weight, the intended effect cannot be obtained. Moreover, even if it adds more than 10 weight part, especially an effect is not recognized.

  The epoxy resin of the present invention does not include an epoxy resin containing a halogen such as bromine in the molecular structure.

  Below, the epoxy resin used by this invention is demonstrated in detail.

  The bisphenol A type epoxy resin is a reaction product of bisphenol A and epichlorohydrin and is represented by the following formula (2).

  Bisphenol F type and AD type epoxy resins are bisphenol F or AD, or the reaction product of bisphenol and epichlorohydrin in which one methyl group added to the bisphenol AD skeleton is substituted with an alkyl group having 2 to 12 carbon atoms. It is a thing. The structural formulas of bisphenol F type and AD type epoxy resins are shown in the following formulas (3) and (4).

  The phenol biphenylene type epoxy resin is an epoxy resin having a structural formula represented by the following formula (5).

  The phenol novolac type epoxy resin is a reaction product of a phenol novolac resin and epichlorohydrin, and is represented by the following formula (6).

  The cresol novolac type epoxy resin is a reaction product of o-cresol novolak resin and epichlorohydrin, and is represented by the following formula (7).

  The naphthol-modified novolac type epoxy resin is an epoxy resin having a structural formula represented by the following formula (8).

  The dicyclopentadiene type epoxy resin is an epoxy resin having a structural formula represented by the following formula (9).

  The triphenyl methane type polyfunctional epoxy resin is an epoxy resin having a structural formula represented by the following formulas (10) and (11).

  Cycloaliphatic epoxy resin is an epoxy compound of the type obtained by oxidizing and epoxidizing the double bond of the cyclohexene ring, for example, aliphatic diepoxy acetal, aliphatic diepoxy diadipate, aliphatic diepoxy carboxylate, vinyl It is a cycloaliphatic epoxy compound such as cyclohexene dioxide. The structural formulas of the aliphatic diepoxycarboxylate and the aliphatic diepoxy didipate are shown in Formula (12).

  The polyglycidylamine type epoxy resin is an epoxy resin having a structural formula represented by the following formula (13).

  Phthalic acid (o-, m-, p-) to hydrophthalic acid (o-, m-, p-) glycidyl ester epoxy resins are phthalic acid (o-, m-, p-) to aromatic rings. Is a reaction product of hydrophthalic acid (o-, m-, p-) and epichlorohydrin, such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, dimethyl glycidyl phthalate, dimer acid glycidyl ester, diglycidyl hexahydrophthalate, It is a compound of dimethyl glycidyl hexahydrophthalate. The structural formula of diglycidyl tetrahydrophthalate is shown in the following formula (14).

  The invention will be described in more detail.

  When only the epoxy compound of the present invention is added without adding an alkylphenol-formaldehyde resin, no crosslinking reaction occurs.

  A feature of the invention is that an alkylphenol-formaldehyde resin as a crosslinking agent and an epoxy compound of the invention are added to a mixture of hydrogenated nitrile rubber and butyl rubber, and a mixture of hydrogenated nitrile rubber, butyl rubber and EPDM to crosslink the composition. In other words, normal physical properties with significantly high modulus and tensile strength can be obtained.

  When the cross-linking curve of the composition containing hydrogenated nitrile rubber is measured, the cross-linking (vulcanization) curve increases when only the alkylphenol / formaldehyde resin is added and when the epoxy compound of the present invention is used in combination. In some cases, it does not always increase and there is almost no change in the crosslinking curve.

  However, the normal properties of the crosslinked rubber are always greatly improved. The present invention has found a unique and unpredictable effect of epoxy compounds on alkylphenol-formaldehyde resin crosslinking of compositions containing hydrogenated nitrile rubber.

  When manufacturing rubber products with high electrical insulation properties, for example, when manufacturing sealing rubber for aluminum electrolytic capacitors, other than imparting properties to the heat, oil and alkali resistant compositions that are the original characteristics of hydrogenated nitrile rubber In addition, it is possible to easily obtain a rubber having high strength, modulus and hardness without increasing the amount of carbon black, that is, having excellent electrical insulation.

  In addition to the alkylphenol / formaldehyde resin and epoxy compound used in the present invention, clay, talc, carbon black, mica, zinc oxide, stearic acid, anti-aging agent, softener, silane coupling, which are usually used as rubber fillers A crosslinkable composition can be produced by optionally adding an agent or the like.

When performing the crosslinking of the composition of the present invention, the crosslinking conditions are not particularly limited, but the crosslinking temperature is preferably 160 to 210 ° C. for 5 to 20 minutes by a heat transfer press.
Secondary crosslinking (also referred to as post-cure) may not be performed, but may be optionally performed when elongation (%) is decreased or hardness is increased. In this case, a normal oven or a vacuum oven used by those skilled in the art is preferably used at 160 ° C. to 210 ° C. for 30 minutes to 3 hours. Furthermore, you may employ | adopt open vulcanizations, such as high frequency bridge | crosslinking used for an extrusion product.

  Furthermore, the present invention provides a rubber product using a crosslinked rubber obtained by crosslinking the composition. The rubber products provided by the present invention are heat-resistant belts, diaphragms, O-rings, heat-resistant water-proof packings, and rubber rolls, such as packings that come into contact with metals such as copper and aluminum, rubber sheets, and the like.

  Furthermore, a product having characteristics as a sealing rubber for aluminum electrolytic capacitors can be provided. That is, by increasing the component ratio of the hydrogenated nitrile rubber, a sealing rubber product having a heat resistance of 125 ° C. to 160 ° C., which could not cope with the heat resistance of the existing 100% butyl rubber sealing rubber, is provided.

  The present invention will be described in more detail with reference to the following examples and comparative examples. In addition, all the raw material compounding quantities in a table | surface are a weight part.

Normal state physical properties were measured according to JIS K6251. The hardness was measured with a type A durometer hardness meter according to JIS K6253. Kgf / cm ² was adopted as the unit of modulus and tensile strength of normal state physical properties. Secondary crosslinking used a vacuum oven with the degree of vacuum adjusted to 30 torr or less. The cross-linking curve was measured at 200 ° C. using a curast meter W type manufactured by JSR Trading Co., Ltd. The alkylphenol-formaldehyde resin used as a cross-linking agent (product Taco Chemical Co., Ltd. manufactured by TAKIROLL 201) was abbreviated as T-201.

Examples 1-2, Comparative Example 1
To 80 parts by weight of hydrogenated nitrile rubber, 20 parts by weight of butyl rubber, 16 parts by weight of alkylphenol / formaldehyde resin, 3 parts by weight of cresol novolac type epoxy resin and 3 parts by weight of biphenyl novolac type epoxy resin are added,
Primary cross-linking at 200 ° C for 10 minutes with heat transfer press Secondary cross-linking at 180 ° C in vacuum oven
For 2 hours. Table 1 shows the compounding recipes of the raw materials of Example 1 and Example 2 and the physical properties (physical properties) of the obtained crosslinked rubber subjected to primary crosslinking and secondary crosslinking. For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 1 in Table 1 .

The crosslinking curves measured at 200 ° C. for Example 1 and Comparative Example 1 are shown in FIG .

  Compared to Comparative Example 1, it can be seen that the cresol novolac type epoxy resin and the biphenyl novolac type epoxy resin significantly increase the modulus and the tensile strength. In other words, it means that the addition amount of carbon black as a reinforcing agent can be reduced to easily blend with excellent insulation. Furthermore, the fact that the elongation (%) can be significantly reduced means that the pressure-induced deformation of products such as diaphragms and capacitor sealing rubber products can be reduced.

(note)
(1) Zettopol 2020, which is a hydrogenated nitrile rubber manufactured by Nippon Zeon Co., Ltd., was used.
(2) Butyl 268, which is a butyl rubber manufactured by Nippon Butyl Co., Ltd., was used.
(3) Asahi Carbon Co., Ltd. carbon black Asahi # 50 was used.
(4) Iceberg, a baked clay manufactured by Burgess Pigment, was used.
(5) Zinc flower manufactured by Shodo Chemical Industry Co., Ltd. was used.
(6) KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd. was used.
(7) Takkol 201 which is an alkylphenol-formaldehyde resin manufactured by Taoka Chemical Co., Ltd. was used.
(8) E0CN-103S which is a cresol novolac type epoxy resin manufactured by Nippon Kayaku Co., Ltd. was used.
(9) NC-3000H, which is a biphenyl novolac type epoxy resin manufactured by Nippon Kayaku Co., Ltd., was used.
(10), (13) (Modulus of Example)-(Modulus of Comparative Example). The same applies to the following embodiments.
(11), (14) (Tensile strength of examples)-(Tensile strength of comparative examples). The same applies to the following embodiments.
(12), (15) (Elongation% of Example)-(Elongation% of Comparative Example). The same applies to the following embodiments.

Examples 3-4, Comparative Example 2
50 parts by weight of hydrogenated nitrile rubber, 35 parts by weight of butyl rubber, 15 parts by weight of EPDM, 8 parts by weight of alkylphenol / formaldehyde resin, 2 parts by weight of triphenylmethane type polyfunctional epoxy resin and 1 part by weight of phenol novolac type epoxy Resin was added and crosslinked as in Example 1.

Table 2 shows the physical properties of Example 3 and Example 4 mixed with the raw materials and the crosslinked rubber obtained in the same manner as Example 1. For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 2 in Table 2 .

Compared with Comparative Example 2, it can be seen that the triphenylmethane type polyfunctional epoxy resin and the phenol novolac type epoxy resin greatly improve the physical properties of the mixture of hydrogenated nitrile rubber, butyl rubber and EPDM.

(note)
(1) Zettopol 2030L, which is a hydrogenated nitrile rubber manufactured by Nippon Zeon Co., Ltd., was used.
(2), (5), (6), (8), (9), (10) are the same as in the first embodiment.
(3) EP33 which is an ethylene / propylene / diene rubber manufactured by JSR Corporation was used.
(4) Asahi Carbon Co., Ltd. carbon black Asahi # 60 was used.
(7) JET-S, a talc manufactured by Asada Flour Milling Co., Ltd., was used.
(11) EOCN502H, which is a triphenylmethane type polyfunctional epoxy resin manufactured by Nippon Kayaku Co., Ltd., was used.
(12) EPPN201, which is a phenol novolac type epoxy resin manufactured by Nippon Kayaku Co., Ltd., was used.

Examples 5-7, Comparative Example 3
20 parts by weight of hydrogenated nitrile rubber, 56 parts by weight of butyl rubber, 24 parts by weight of EPDM, 18 parts by weight of alkylphenol / formaldehyde resin, and 1 part by weight of hydrogenated bisphenol A type epoxy resin and 1 part by weight of triglyceride as epoxy resin implementing phenyl methane type polyfunctional epoxy resin added with the composition example 5,1 parts by weight of the polyphenol type epoxy resins and 3 composition obtained by adding the parts by weight of phenol novolak type epoxy resin examples of 6,2 parts by weight the composition obtained by adding a mixture of Fe Roh Rubifeniren epoxy resin and biphenol glycidyl ether adjust formulated as example 7, it shows the physical properties of crosslinked in the same manner as in example 1 in Table 3. For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 3 in Table 3 .

  Compared with Comparative Example 3, it can be seen that the epoxy resin significantly improves the physical properties of a mixture of hydrogenated nitrile rubber, butyl rubber, and EPDM.

(note)
(1) Zettopol 1020, a hydrogenated nitrile rubber manufactured by Nippon Zeon Co., Ltd., was used.
(2), (5), (6), (8), (9), (10) are the same as in the first embodiment.
(3), (4), and (7) are the same as in the third embodiment.
(11) EP-4080E, which is a hydrogenated bisphenol A type epoxy resin manufactured by ADEKA Corporation, was used.
(12) EP-4901, which is a polyphenol type epoxy resin manufactured by ADEKA Corporation, was used.
(13) Same as Example 3.
(14) Same as Example 4.
(15) CER-3000-L which is a mixture of a phenolic epoxy resin and biphenol glycidyl ether manufactured by Nippon Kasei Co., Ltd. was used.

Example 8, Comparative Example 4
30 parts by weight of hydrogenated nitrile rubber, 70 parts by weight of butyl rubber, 8 parts by weight of alkylphenol / formaldehyde resin, and 4 parts by weight of cresol novolac type epoxy resin as an epoxy resin were added and crosslinked at 200 ° C. for 10 minutes. Table 4 shows the physical properties. For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 4 in Table 4 .

Compared to Comparative Example 4, it can be seen that the physical properties of the crosslinked rubber to which 8 parts by weight of an alkylphenol-formaldehyde resin and a cresol novolac type epoxy resin are added are greatly improved.

(note)
(1) Same as Example 5.
(2), (3), (4), (6), (7), (8) Same as Example 1.
(5) Same as Example 3.
(9) E0CN1020, which is a cresol novolac type epoxy resin manufactured by Nippon Hoten Co., Ltd., was used.

Example 9, Comparative Example 5
30 parts by weight of hydrogenated nitrile rubber, 70 parts by weight of butyl rubber, 20 parts by weight of alkylphenol / formaldehyde resin and 4 parts by weight of bisphenol F type epoxy resin as an epoxy resin are added, and the primary crosslinking is carried out at 200 ° C. Table 9 shows the physical properties of a crosslinked rubber which was subjected to secondary crosslinking for 10 minutes at 185 ° C. for 2 hours in a vacuum oven. For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 5 in Table 5 .
The cross-linking curves measured at 200 ° C. for Example 9 and Comparative Example 5 are shown in FIG .

Compared to Comparative Example 5, the crosslinked rubber to which 20 parts by weight of alkylphenol-formaldehyde resin and bisphenol F-type epoxy resin are added shows that the physical properties are greatly improved.

(note)
(1), (2), (3), (4), (6), (7), (8) Same as Example 1.
(5) Same as Example 3.
(9) jEP4004P which is a bisphenol F type epoxy resin manufactured by Japan Epoxy Resin Co., Ltd. was used.

Examples 10-11, Comparative Examples 6-7
To 60 parts by weight of hydrogenated nitrile rubber, 28 parts by weight of butyl rubber, and 12 parts by weight of EPDM, 16 parts by weight of an alkylphenol / formaldehyde resin and 3 parts by weight of a cresol novolac type epoxy resin were added (Example 11) at 200 ° C. Crosslinked for 10 minutes. For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 6 in Table 6 . The cross-linking curves measured at 200 ° C. for Example 10 and Comparative Example 6 are shown in FIG .

To 25 parts by weight of hydrogenated nitrile rubber, 53 parts by weight of butyl rubber, and 22 parts by weight of EPDM, 16 parts by weight of an alkylphenol / formaldehyde resin and 3 parts by weight of a cresol novolac type epoxy resin were added (Example 12) at 200 ° C. Crosslinked for 10 minutes. For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 7 in Table 6 .

The cresol novolac type epoxy resin is a modulus (Kgf / c) and tensile strength (Kgf / c) of a mixture of a hydrogenated nitrile rubber to which 16 parts by weight of an alkylphenol-formaldehyde resin is added, a butyl rubber, and EPDM. Can be seen to be significantly higher.

(note)
(1), (2), (5), (6), (8), (9), (10) Same as Example 1.
(3), (4), (7) Same as Example 3.
(11) Same as Example 8.

Example 12, Comparative Example 8
To a mixture of 50 parts by weight of hydrogenated nitrile rubber and 50 parts by weight of butyl rubber, 8 parts by weight of an alkylphenol / formaldehyde resin and 3 parts by weight of a phenol novolac type epoxy resin were added and crosslinked in the same manner as in Example 1. The physical properties of the crosslinked rubber are shown in Example 12 of Table 7 . For comparison, the physical properties of a crosslinked rubber obtained by crosslinking with a raw material formulation not containing an epoxy resin are shown in Comparative Example 8 in Table 7 . The crosslinking curves measured at 200 ° C. for Example 12 and Comparative Example 7 are shown in FIG .

A mixture of two types of rubber, 50 parts by weight of hydrogenated nitrile rubber and 50 parts by weight of butyl rubber,
It can be seen that a good crosslinked rubber can be obtained by crosslinking with 8 parts by weight of an alkylphenol / formaldehyde resin and 3 parts by weight of a phenol novolac epoxy resin.

(note)
(1), (2), (3), (4), (6), (7), (8) Same as Example 1.
(9) Same as Example 3.

[The invention's effect]
Hydrogenated nitrile rubber and butyl rubber, and a mixture of hydrogenated nitrile rubber, butyl rubber and EPDM are greatly improved in cross-linked rubber strength by alkylphenol-formaldehyde resin and epoxy resin. As can be seen from the examples in which the elongation (%) at break is also low, 100% by weight or more of the calcined clay is added, it is desirable to reduce the deformation due to externally applied force. For example, sealing of an aluminum electrolytic capacitor It can be used for products such as rubber and diaphragm.

  By mixing the hydrogenated nitrile rubber of the present invention with butyl rubber or butyl rubber and EPDM, it is possible to impart characteristics having different characteristics.

  As the ratio of the hydrogenated nitrile rubber increases as the rubber component in the composition, the heat resistance and oil resistance can be improved. And the target heat resistance can also be adjusted by adjusting the ratio of hydrogenated nitrile rubber.

  As a feature when hydrogenated nitrile rubber is mixed with butyl rubber or butyl rubber and EPDM, high filling of clay, talc, silica or the like becomes extremely easy. In the case of blending only hydrogenated nitrile rubber, the release of rubber from the open roll (bagging phenomenon) occurs when the amount of the filler increases, but bagging can be prevented by mixing butyl rubber or butyl rubber with EPDM. The composition of the present invention does not cause bagging, can produce an unvulcanized rubber sheet having excellent processability, and facilitates the molding of an unvulcanized rubber sheet for press molding.

  Furthermore, when considering the price of the composition, hydrogenated nitrile rubber is expensive, and as a measure for the price of the product, a high filler content is significant. This can be achieved by mixing butyl rubber or butyl rubber with EPDM.

  When manufacturing a sealing rubber of an aluminum electrolytic capacitor with better performance such as heat resistance, it is a representative product that can be achieved by the present invention, and makes it possible to provide an optimal crosslinked rubber product.

FIG. 1 shows a cross-linking curve measured at 200 ° C. using the curast meter of Example 1 and Comparative Example 1. FIG. 2 shows the crosslinking curves measured at 200 ° C. using the curastometers of Example 9 and Comparative Example 5. FIG. 3 shows cross-linking curves measured at 200 ° C. using the curastometers of Example 10 and Comparative Example 6. FIG. 4 shows the cross-linking curves measured at 200 ° C. using the curast meter of Example 12 and Comparative Example 7.

Claims (6)

  (A) 5 parts by weight to 95 parts by weight of hydrogenated acrylonitrile / butadiene rubber, 95 parts by weight to 5 parts by weight of isoprene / isobutylene rubber, and 0 parts by weight to 30 parts by weight of ethylene / propylene rubber A crosslinkable rubber composition comprising (B) 5 to 25 parts by weight of an alkylphenol / formaldehyde resin and (C) 0.3 to 10 parts by weight of an epoxy compound. 2. The crosslinkable rubber composition according to claim 1, wherein the alkylphenol-formaldehyde resin is a compound represented by the following formula (1).

  Bisphenol type in which one methyl group added to the skeleton of bisphenol A type epoxy resin, bisphenol F type or AD type epoxy resin, or bisphenol AD type epoxy resin is substituted with an alkyl group having 2 to 12 carbon atoms. Epoxy resin, phenol biphenylene type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, naphthol modified novolak type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type polyfunctional epoxy resin, cycloaliphatic epoxy One or two selected from the group consisting of a resin, a polyglycidylamine type epoxy resin, a glycidyl ester epoxy resin of phthalic acid (o-, m-, p-) or hydrophthalic acid (o-, m-, p-) More than types Crosslinkable rubber composition according to claim 1, characterized in that there.   Epoxy resin added to a mixture of hydrogenated acrylonitrile / butadiene rubber, isoprene / isobutylene rubber, and ethylene / propylene rubber is a skeleton of bisphenol A type epoxy resin, bisphenol F type or AD type epoxy resin, bisphenol AD type epoxy resin. Bisphenol type epoxy resin, phenol biphenylene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthol modified novolak type epoxy in which one methyl group added to the alkyl group is substituted with an alkyl group having 2 to 12 carbon atoms Resin, dicyclopentadiene type epoxy resin, triphenylmethane type polyfunctional epoxy resin, cycloaliphatic epoxy resin, polyglycidylamine type epoxy resin, phthalic acid (o-, m-, p-) 2. The hydrogenated acrylonitrile-butadiene rubber according to claim 1, wherein the hydrogenated acrylonitrile-butadiene rubber is selected from the group consisting of glycidyl ester epoxy resins of hydrophthalic acid (o-, m-, p-). A crosslinked rubber product obtained by crosslinking a mixture of isoprene / isobutylene rubber and ethylene / propylene rubber.   (A) 5 parts by weight to 95 parts by weight of hydrogenated acrylonitrile / butadiene rubber, 95 parts by weight to 5 parts by weight of isoprene / isobutylene rubber, and 0 parts by weight to 30 parts by weight of ethylene / propylene rubber (B) A method of crosslinking a composition comprising 5 to 25 parts by weight of an alkylphenol / formaldehyde resin and (C) 0.3 to 10 parts by weight of an epoxy compound.   A sealing rubber product used for an aluminum electrolytic capacitor obtained by the crosslinking method according to claim 5.

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