Rubber composition and vulcanized molded product

Abstract

To provide a rubber composition that is excellent in kneading processability and is suitable for producing a vulcanized molded article that is good in compression set characteristics and is excellent in low-temperature characteristics and electrical insulating properties.SOLUTION: The present invention relates to a rubber composition containing an ethylene-butene-diene terpolymer, silica having a CTAB specific surface area of 30 m2 / g or more and 150 m2 / g or less, a silane coupling agent, and a crosslinking agent. A content of the silica per 100 pts.wt. of the ethylene-butene-diene terpolymer is 25 pts.wt. or more and 90 pts.wt. or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a rubber composition and a vulcanization molded article using the same. [Background technology]

[0002] Conventionally, rubber materials such as nitrile rubber (NBR), fluororubber (FKM), and acrylic rubber (ACM) have been widely used as materials for various rubber molded products (e.g., sealing parts, electrical insulators, vibration-proof rubber, soundproof rubber, general industrial rubber, etc.) due to their properties. However, these materials have a problem in that they cannot fully exhibit their rubber properties in low-temperature environments (e.g., below -40°C), and there is a demand for rubber materials with excellent cold resistance.

[0003] Ethylene-propylene-diene terpolymer (hereinafter, also referred to as "EPDM") is a widely known rubber material. EPDM has better cold resistance than the above-mentioned rubber materials and can exhibit sufficient rubber properties even in low-temperature environments, so it can be used as a rubber material for cold-resistant sealing parts. However, in recent years, sealing parts may require even greater cold resistance, and there is a problem that even EPDM cannot exhibit sufficient rubber properties.

[0004] Ethylene-butene-diene terpolymer (EBDM) has been attracting attention as a rubber material to replace EPDM. Patent Document 1 discloses that a sealing part for high-pressure hydrogen equipment manufactured using a rubber composition containing ethylene-butene-ethylidenenorbornene terpolymer (EBENB) as an ethylene-butene-diene terpolymer and a filler such as carbon black, silicic acid, or silicate has excellent low-temperature sealing properties and blister resistance. Patent Document 2 discloses that a rubber composition containing EBENB, carbon black, a hardness modifier, and a crosslinking agent can be used to obtain a rubber molded product having a hardness equivalent to that of a rubber product using conventional EPDM and excellent low-temperature sealing properties.

[0005] On the other hand, in recent years, sealing products are required to have not only high sealing properties in low temperature environments, but also electrical insulation properties from the viewpoint of corrosion prevention. In addition, since EBENB has very high adhesion as a polymer copolymer, it adheres to the surfaces of kneading machines, especially open roll kneading machines, so there is a demand for improving productivity (kneading processability) in the kneading process of rubber compositions.

[0006] Patent Documents 1 and 2 teach that, for example, by using a rubber composition containing EBENB and carbon black, excellent low-temperature sealing properties can be imparted to a rubber molded product (sealed part), but do not mention electrical insulation and kneading processability. Therefore, there is a demand for the development of a rubber composition that can impart both low-temperature sealing properties and electrical insulation properties to a sealed part and has excellent kneading processability. In addition, since a sealed product partially undergoes permanent deformation (distortion) during long-term use, which reduces the sealing performance, good compression set properties are also desired when the rubber composition is used for sealing purposes. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2017-170189 [Patent Document 2] International Publication No. 2017-170190 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a rubber composition which is excellent in kneading processability, good compression set characteristics, low-temperature characteristics and electrical insulation, and is suitable for producing vulcanization molded articles. [Means for solving the problem]

[0009] The rubber composition according to the embodiment of the present invention is a rubber composition comprising an ethylene-butene-diene terpolymer and 30m 2 / g or more 150m 2 / g or less, a silane coupling agent, and a crosslinking agent, and the content of the silica relative to 100 parts by weight of the ethylene-butene-diene terpolymer is 25 parts by weight or more and 90 parts by weight or less.

[0010] In one embodiment of the present invention, the ethylene-butene-diene terpolymer is an ethylene-butene-ethylidenenorbornene terpolymer.

[0011] In one embodiment of the present invention, the ethylene-butene-diene terpolymer has an iodine value of 3 or more and 20 or less.

[0012] In one embodiment of the present invention, the content of the silane coupling agent relative to 100 parts by weight of the ethylene-butene-diene terpolymer is 0.5 parts by weight or more and 3.0 parts by weight or less.

[0013] In one embodiment of the invention, the crosslinking agent is an organic peroxide.

[0014] The vulcanization molded article according to the embodiment of the present invention is obtained by vulcanization molding the above rubber composition.

[0015] In one embodiment of the vulcanized molded product of the present invention, the TR-70 value measured in accordance with JIS K6261:2006 is −40° C. or less.

[0016] In one embodiment of the vulcanized molded product of the present invention, the volume resistivity measured in accordance with JIS K6271-1:2015 is 1×10 12 Ω·cm or more.

[0017] In one embodiment of the vulcanized molded product of the present invention, the compression set measured in accordance with JIS K6262:2013 under conditions of 130°C and 70 hours is 20% or less.

[0018] In one embodiment of the present invention, the vulcanization molded article is a sealing part. Effect of the Invention

[0019] According to the present invention, it is possible to provide a rubber composition which is excellent in kneading processability, has good compression set characteristics, and is suitable for producing vulcanization molded products which are excellent in low-temperature characteristics and electrical insulation properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described. The rubber composition according to this embodiment contains an ethylene-butene-diene terpolymer (hereinafter also referred to as "EBDM") as a rubber component, silica as a filler, a silane coupling agent, and a crosslinking agent. The silica used is 30m 2 / g or more 150m 2 / g or less, and the content of silica in the rubber composition is 25 parts by weight or more and 90 parts by weight or less per 100 parts by weight of ethylene-butene-diene terpolymer. In the EBDM-containing rubber composition according to the present embodiment, by blending silica having a predetermined CTAB specific surface area within a predetermined content range, a rubber composition suitable for producing a vulcanization molded product having excellent kneading processability and excellent both low-temperature properties and electrical insulation properties can be obtained. In addition, the addition of a silane coupling agent imparts good compression set properties to the obtained vulcanization molded product. Furthermore, since the vulcanization molded product exhibits excellent low-temperature properties, sealing parts, which are an example of the use form of such a vulcanization molded product, exhibit excellent sealing performance in a low-temperature environment. Below, each component constituting the rubber composition according to the present embodiment will be described in detail.

[0021] <Rubber component> In this embodiment, the rubber composition contains EBDM as a main component (rubber component) for vulcanized molded products. As the ethylene-butene-diene terpolymer, for example, ethylene-butene-ethylidene norbornene terpolymer (hereinafter also referred to as "EBENB") is preferable. The properties of rubber materials such as EBENB and EPDM have a significant effect on the material cost and production efficiency of the entire rubber composition (or vulcanized molded product). In addition, EBDM has excellent flexibility compared to EPDM, and therefore has excellent cold resistance (low temperature characteristics), and excellent processability such as kneadability, dispersibility, and moldability, and production efficiency is greatly improved, so that the cost in the production process can be reduced. Thus, according to the rubber composition according to this embodiment using EBDM, particularly EBENB, it has excellent low temperature characteristics compared to conventional rubber compositions using EPDM, and from the viewpoint of material cost and production efficiency, the production cost of vulcanized molded products can be reduced.

[0022] As the EBDM, any of those obtained by copolymerizing ethylene and butene with various diene components can be used. When EBENB is used as the EBDM, the EBDM is not particularly limited as long as it is obtained by copolymerizing ethylene and butene with ethylidenenorbornene. As the EBDM, a copolymer prepared by synthesizing each monomer component may be used, or various commercially available products, such as "EBT K-9330M" manufactured by Mitsui Chemicals, Inc., may be used as they are.

[0023] The iodine value (g / 100g) of EBDM is preferably 3 to 20, more preferably 5 to 18. By having an iodine value in the range of 3 to 20, the vulcanized molded product is endowed with excellent heat aging resistance and weather resistance, and deterioration of the vulcanized molded product can be prevented. In addition, the molecular state of EBDM can be maintained stable even in a low-temperature environment, and low-temperature properties can be improved.

[0024] EBDM has a higher Mooney viscosity (ML) than EPDM. 1+4(100°C), and is excellent in terms of processability (e.g., kneadability, moldability, etc.). Therefore, by using EBDM instead of EPDM, productivity such as molding efficiency can be improved and production costs can be reduced. The Mooney viscosity ML of such EBDM is 1+4 (100°C) is preferably 10 or more and 45 or less, more preferably 15 or more and 35 or less. Mooney viscosity ML 1+4 By making the Mooney viscosity ML (100°C) 10 or more, it is possible to prevent the compression set in the vulcanized molded product from becoming too large, and also to impart an appropriate tensile strength to the product. 1+4 By making the Mooney viscosity (ML) at 100°C equal to or less than 45, it is possible to prevent the processability of the rubber composition from being deteriorated. 1+4 (100°C) can be measured in accordance with the provisions of JIS K6300-1:2013.

[0025] The content of the ethylene component in the EBDM is preferably 60 mol% or more and 80 mol% or less, and more preferably 65 mol% or more and 75 mol% or less. When the content of the ethylene component is in the range of 60 mol% or more and 80 mol% or less, the glass transition temperature Tg of the EBDM reaches a minimum value, and the cold resistance is improved.

[0026] In the rubber composition, the EBDM constituting the rubber component may be used alone or in combination of two or more kinds. In addition, ethylene-propylene-diene terpolymer (EPDM) and the like may be used in combination as another rubber component.

[0027] <Filling agent> In this embodiment, the rubber composition is 30 2 / g or more 150m 2 The rubber composition contains silica with a CTAB (cetyltrimethylammonium bromide) specific surface area of ​​30 m / g or less. The inclusion of silica, which acts as a filler, improves the mechanical strength and compression set of the resulting vulcanized molded product while maintaining the inherent electrical insulation of the polymer. In addition, the CTAB specific surface area of ​​the silica is 30 m2 / g or more 150m 2 / g or less, the rubber composition is prevented from adhering to the roll surface of a kneader, particularly a roll kneader, during the kneading process of the rubber composition, and kneading processability is improved. As a result, the workability in the kneading process is improved, and productivity can be improved. Furthermore, 2 By using silica with a CTAB specific surface area of ​​30 m or less, the dispersibility of the silica is improved and the compression set properties are improved. 2 / g or more 150m 2 By using silica having a specific surface area of ​​30 m / g or less, it is possible to provide a rubber composition which is excellent in kneading processability, and further, excellent in electrical insulation, and which can be used to produce a vulcanized molded product having improved compression set properties. In particular, the CTAB specific surface area of ​​silica is 30 m 2 / g or more 100m 2 / g or less, and the use of silica having a CTAB specific surface area in this range further improves the compression set properties.

[0028] As a commercially available product of silica, for example, "Nipsil E74P" (CTAB specific surface area: 33 m) manufactured by Tosoh Silica Corporation is available. 2 / g), Evonik's "Carplex (registered trademark) #101" (CTAB specific surface area: 50 m 2 / g), and "Ultrasil (registered trademark) 360" manufactured by Evonik (CTAB specific surface area: 55 m 2 / g), and Evonik's "Carplex (registered trademark) #1120" (CTAB specific surface area: 85 m 2 / g), and Tosoh Silica's "Nipsil ER" (CTAB specific surface area: 115 m 2 / g), and Evonik's "Carplex (registered trademark) #67" (CTAB specific surface area: 140 m 2 / g) etc. The silica may be used alone or in combination of two or more kinds.

[0029] The content of silica contained in the rubber composition is preferably 30 parts by weight or more and 90 parts by weight or less, more preferably 30 parts by weight or more and 70 parts by weight or less, based on 100 parts by weight of EBDM. By making the content 30 parts by weight or more and 90 parts by weight or less, the rubber composition exhibits excellent kneading processability, and excellent low-temperature properties are imparted to the vulcanized molded product. In this way, by making the content of silica 30 parts by weight or more and 90 parts by weight or less based on 100 parts by weight of EBDM, a rubber composition that can produce a vulcanized molded product having excellent kneading processability and low-temperature properties can be provided. In particular, the content of silica is preferably 30 parts by weight or more and 70 parts by weight or less, and by strictly controlling the content of silica according to the desired hardness, the compression set property is further improved.

[0030] The rubber composition may further contain a filler other than silica. When using a combination of fillers other than silica, the type and amount of the other fillers can be determined according to the purpose as long as the content of silica is within the above range. As such other fillers, carbon black, calcium carbonate, clay, talc, etc., which are generally used as reinforcing materials to be added to rubber compositions, may be added as appropriate to obtain desired physical properties. In addition, when a filler showing electrical conductivity such as carbon black is combined for coloring, it is appropriately adjusted within the range in which the vulcanized molded product shows the desired electrical insulation.

[0031] <Silane coupling agent> The rubber composition according to the present embodiment further contains a silane coupling agent. Examples of the silane coupling agent include vinyl group-containing alkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(2-methoxyethoxy)silane, and amino group-containing alkoxysilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, and N-β-aminoethyl-γ-aminopropyltriethoxysilane. The silane coupling agent may be used alone or in combination of two or more. The amount of the silane coupling agent is not particularly limited, but is preferably 0.5 parts by weight or more and 3.0 parts by weight or less, and more preferably 0.5 parts by weight or more and 1.5 parts by weight or less, relative to 100 parts by weight of EBDM. By adding an appropriate amount of the silane coupling agent, the adhesion between the rubber and the silica is increased, and the compression set property of the vulcanized molded product is improved.

[0032] <Crosslinking agent> The rubber composition further contains a crosslinking agent for forming crosslinks of EBDM. As the crosslinking agent, organic peroxides are mainly preferred. Examples of the organic peroxides include dialkyl peroxides, peroxyketals, diacyl peroxides, and peroxyesters. Specific examples include di-tert-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, tert-butylcumyl peroxide, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butylperoxybenzoate, tert-butylperoxyisopropylcarbonate, and n-butyl-4,4-bis(tert-butylperoxy)valerate. The crosslinking agent may be used alone or in combination of two or more.

[0033] The amount of the crosslinking agent is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of EBDM. By using a crosslinking agent in an amount within the range of 0.5 to 10 parts by weight, it is possible to prevent the rubber composition from foaming during vulcanization of the EBDM, which would make it impossible to perform vulcanization molding, and the crosslink density is good, making it easier to produce a vulcanization molded product that exhibits sufficient physical properties.

[0034] As such a crosslinking agent, a commercially available product may be used as it is, or a masterbatch containing the above-mentioned organic peroxide may be used. The masterbatch is preferable in that it can improve the kneading property and dispersibility when preparing the rubber composition.

[0035] <Other additives> The rubber composition according to the present embodiment may further contain a crosslinking accelerator as necessary. As the crosslinking accelerator, triallyl isocyanurate (TAIC), triallyl cyanate (TAC), liquid polybutadiene, N,N'-m-phenylenedimaleimide, trimethylolpropane trimethacrylate, etc. may be used. The crosslinking accelerator may be used alone or in combination of two or more. The amount of the crosslinking accelerator is not particularly limited, but is preferably 0.5 parts by weight or more and 3.0 parts by weight or less with respect to 100 parts by weight of EBDM. By adding an appropriate amount of the crosslinking accelerator, the crosslinking efficiency is improved, and further, the heat resistance and mechanical properties are improved, so that the stability of the vulcanized molded product may also be improved.

[0036] The rubber composition according to the present embodiment may further contain a plasticizer as necessary. Examples of the plasticizer include process oils mainly composed of aliphatic hydrocarbons, such as "Diana Process Oil PW-380" manufactured by Idemitsu Kosan Co., Ltd. and "Diana Process Oil PW-220" manufactured by Idemitsu Kosan Co., Ltd. The plasticizers may be used alone or in combination of two or more. In particular, process oils are lower molecular weight than paraffin wax, which has a similar chemical structure, and therefore are more preferable in that they provide unique effects that cannot be achieved when paraffin wax is blended. The blending amount of the plasticizer is not particularly limited, but is preferably 1.0 part by weight or more and 30 parts by weight or less with respect to 100 parts by weight of EBDM.

[0037] The rubber composition according to the present embodiment may further contain a lubricant as necessary. The lubricant has a melting point of 50°C to 100°C, which is near the surface temperature of the kneader, and is preferably a fatty acid-based lubricant. Examples of the fatty acid-based lubricant include fatty acid amide, fatty acid zinc, and fatty acid ester. Examples of the fatty acid amide include saturated fatty acid amide and unsaturated fatty acid amide, and may be monoamide, substituted amide, bisamide, or methylol amide depending on the structure. Examples of the fatty acid zinc include saturated fatty acid zinc, unsaturated fatty acid zinc, derivatives thereof, and mixtures thereof. Examples of the fatty acid ester include esters of lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid. In addition to fatty acid-based lubricants, non-zinc-based lubricants and organosilicone-based lubricants can also be applied. The amount of the lubricant is not particularly limited, but is preferably 0.5 parts by weight or more and 3.0 parts by weight or less with respect to 100 parts by weight of EBDM. By adding an appropriate amount of lubricant, the kneading processability is improved and the occurrence of oil bleeding can be prevented.

[0038] In addition to the above components, rubber compounding agents generally used in the rubber industry, such as an acid acceptor and an antioxidant, may be added to the rubber composition as necessary. The total amount of each rubber compounding agent is preferably 300 parts by weight or less per 100 parts by weight of EBDM.

[0039] <Method of manufacturing rubber composition> The method for producing the rubber composition according to the present embodiment is not particularly limited, but the rubber composition can be produced by appropriately mixing the above-described EBDM, silica, silane coupling agent, and crosslinking agent, as well as any various additives that are mixed as necessary, in a predetermined ratio, and then kneading the mixture using a kneading machine such as a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, a kneader, or a high-shear mixer. Note that, prior to kneading, preliminary kneading may be performed as necessary.

[0040] <Vulcanization molded products> A vulcanized molded product can be manufactured by vulcanizing the rubber composition according to the present embodiment. The vulcanization of the rubber composition is generally carried out by pressurized vulcanization at about 150 to 230°C for about 0.5 to 30 minutes using an injection molding machine, a compression molding machine, or the like. After such primary vulcanization (pressurized vulcanization) is carried out, secondary vulcanization may be carried out as necessary to ensure that the inside of the vulcanized molded product is vulcanized. The secondary vulcanization can generally be carried out by oven heating at about 150 to 250°C for about 0.5 to 24 hours.

[0041] The vulcanized molded article obtained by vulcanizing the rubber composition according to the present embodiment exhibits excellent low-temperature properties even at temperatures below -40°C, and is suitable for use in low-temperature environments (for example, from -40°C to -60°C). As the low-temperature properties of such a vulcanized molded article, for example, the TR-70 value measured in accordance with JIS K6261:2006 is preferably -40°C or less.

[0042] In addition, the vulcanized molded article obtained by vulcanizing the rubber composition according to the present embodiment exhibits excellent electrical insulation. For example, the electrical insulation of such a vulcanized molded article is characterized by a volume resistivity of 1×10 or less as measured in accordance with JIS K6271-1:2015. 12 It is preferable that the resistivity is Ω·cm or more.

[0043] In addition, the vulcanized molded product obtained by vulcanizing the rubber composition according to the present embodiment preferably has good compression set properties. For example, the compression set property of such a vulcanized molded product is preferably 20% or less, more preferably 15% or less, as measured at 130°C for 70 hours in accordance with JIS K6262:2013.

[0044] The vulcanization molded product according to the present embodiment exhibits good compression set properties, and further has excellent low-temperature properties and electrical insulation properties, and is therefore suitable for use as, for example, sealing parts and insulators. In particular, when the vulcanization molded product is a sealing part, such a sealing part exhibits excellent sealing performance in a low-temperature environment. In particular, the vulcanization molded product is suitable for use as a gasket for electromobility (e-Mobility) as a sealing part that requires sealing properties and electrical insulation properties in a low-temperature environment.

[0045] The shape of the vulcanization molded product is not particularly limited, and can be various shapes according to the application. For example, when the vulcanization molded product is used as a sealing part, the shape of the sealing part can be an O-ring, a gasket, a packing, a sheet, etc. In addition, the application of the vulcanization molded product is not limited to the above-mentioned sealing parts, and it is also suitable as other industrial sealing parts such as insulating seals and seals for cold regions.

[0046] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes all aspects encompassed by the concept of the present invention and the scope of the claims, and can be modified in various ways within the scope of the present invention. EXAMPLES

[0047] Examples of the present invention will be described below, but the present invention is not limited to these examples as long as they do not depart from the spirit of the present invention.

[0048] Example 1 A rubber composition was prepared by kneading 100 parts by weight of EBDM (iodine value: 16 (g / 100g), product name "EBT K-9330M", manufactured by Mitsui Chemicals), 30 parts by weight of silica A (product name "Nipsil E74P", manufactured by Tosoh Silica Corporation), 1 part by weight of a silane coupling agent (product name "A171", manufactured by Momentive Corp.), 3 parts by weight of a crosslinking agent (product name "Perkmyl D", manufactured by Nippon Oil & Fats Co., Ltd.), and 1 part by weight of a lubricant (product name "Diamid 0-200T", manufactured by Nippon Kasei Chemical Industry Co., Ltd.) using an open roll kneader.

[0049] <Mixing processability> The kneading processability of the obtained rubber composition was evaluated based on the adhesion to the kneader surface. If stable kneading was possible, it was evaluated as "Good". If the rubber composition adhered too much to the kneader surface and kneading could not be continued, it was evaluated as "Poor". The results are shown in Table 1.

[0050] <Low temperature characteristics> The obtained rubber composition was subjected to pressure vulcanization (primary vulcanization) at 180°C for 10 minutes and open vulcanization (secondary vulcanization) at 150°C for 24 hours using a sheet mold, and a sheet-like vulcanized molded product with a thickness of 2 mm was prepared as a test piece. The temperature at TR-70 was measured for the test piece of the obtained vulcanized molded product in accordance with JIS K6261:2006. TR-70 is the temperature at which the shrinkage rate becomes 70% when the test piece is stretched 50% and frozen, and then heated to recover the elastic modulus. The lower the temperature measured by TR-70, the more the rubber elasticity is recovered at low temperatures, indicating excellent low-temperature characteristics. For sealing parts that impart sealing properties by rubber elasticity, the lower the temperature is, the more desirable it is. It can be seen that such material characteristics show favorable sealing behavior from the viewpoint of rubber elasticity. If the TR-70 was -40°C or lower, it was evaluated as "good", and if it was higher than -40°C, it was evaluated as "bad". The results are shown in Table 1.

[0051] <Electrical insulation> For the test pieces of the obtained vulcanization molded products, 500 V was applied between the electrodes in accordance with JIS K6271-1:2015, and the volume resistivity was measured after 1 minute. The higher the volume resistivity, the better the electrical insulation. 12 If it is Ω·cm or more, it is marked as "Yes", and if it is 1×10 12 If it was less than Ω·cm, it was rated as "×." The results are shown in Table 1.

[0052] <Compression set characteristics> Three test pieces of the obtained vulcanized molded product were stacked, and the compression set rate after 70 hours at 130°C in air was measured in accordance with JIS K6262:2013. The lower the compression set rate, the better the compression set properties. A compression set rate of 15% or less was evaluated as "Good", a rate of 20% or less was evaluated as "Good", and a rate of over 20% was evaluated as "Poor". A rate of "Good" or better was evaluated as meeting the pass level. The results are shown in Table 1.

[0053] Example 2 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that the compounding amount of silica A was 60 parts by weight, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0054] Example 3 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that the compounding amount of silica A was 90 parts by weight, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0055] Example 4 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that silica B (product name: "Carplex (registered trademark) #101", manufactured by Evonik Corporation) was used instead of silica A, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0056] Example 5 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that silica C (product name: "Ultrasil (registered trademark) 360", manufactured by Evonik Corporation) was used instead of silica A, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0057] Example 6 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that silica D (product name: "Carplex (registered trademark) #1120", manufactured by Evonik Corporation) was used instead of silica A, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0058] Example 7 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that silica E (trade name: "Nipsil ER", manufactured by Tosoh Silica Corporation) was used instead of silica A, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0059] Example 8 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that silica F (product name: "Carplex (registered trademark) #67", manufactured by Evonik Corporation) was used instead of silica A, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0060] Comparative Example 1 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that the compounding amount of silica A was 20 parts by weight, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0061] Comparative Example 2 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that the compounded amount of silica A was 100 parts by weight, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0062] Comparative Example 3 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that 30 parts by weight of silica G (trade name: "Nipsil LP", manufactured by Tosoh Silica Corporation) was used instead of silica A, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0063] Comparative Example 4 A rubber composition and a vulcanized molded product thereof were prepared in the same manner as in Example 1, except that 20 parts by weight of silica H (product name: "Ultrasil (registered trademark) 9500GR", manufactured by Evonik Corporation) were used instead of silica A, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0064] Comparative Example 5 A rubber composition and a vulcanized molded product thereof were prepared in the same manner as in Example 1, except that 80 parts by weight of carbon black (ISAF (Intermediate Super Abrasion Furnace) carbon black: trade name "Show Black N220", manufactured by Cabot Japan Co., Ltd.) was compounded instead of silica A and no silane coupling agent was added, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0065] Comparative Example 6 Except for not containing a silane coupling agent, a rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0066] Comparative Example 7 A rubber composition and a vulcanized molded article thereof were prepared in the same manner as in Example 1, except that EPDM (product name: "EP33", manufactured by JSR Corporation) was used instead of EBDM, and the above measurements and evaluations were carried out. The results are shown in Table 1.

[0067] [Table 1]

[0068] The components shown in Table 1 above are as follows. EBDM: Ethylene-butene-diene terpolymer (iodine value: 16 (g / 100g), product name "EBT K-9330M", manufactured by Mitsui Chemicals, Inc.) EPDM: Ethylene-propylene-diene terpolymer (product name "EP33", manufactured by JSR Corporation) Silica A: Product name "Nipsil E74P", manufactured by Tosoh Silica Corporation (CTAB specific surface area: 33 m 2 / g) Silica B: Product name "Carplex (registered trademark) #101", manufactured by Evonik (CTAB specific surface area: 50 m 2 / g) Silica C: Trade name "Ultrasil (registered trademark) 360", manufactured by Evonik (CTAB specific surface area: 55 m 2 / g) Silica D: Trade name "Carplex (registered trademark) #1120", manufactured by Evonik (CTAB specific surface area: 85 m 2 / g) Silica E: Product name "Nipsil ER", manufactured by Tosoh Silica Corporation (CTAB specific surface area: 115 m 2 / g) Silica F: Product name "Carplex (registered trademark) #67", manufactured by Evonik (CTAB specific surface area: 140 m 2 / g) Silica G: Product name "Nipsil LP", manufactured by Tosoh Silica Corporation (CTAB specific surface area: 154 m 2 / g) Silica H: Trade name "Ultrasil (registered trademark) 9500GR", manufactured by Evonik (CTAB specific surface area: 220 m 2 / g) Silane coupling agent: Product name "A171", manufactured by Momentive Corporation Crosslinking agent: Product name "Perkmyl D", manufactured by Nippon Oil & Fats Co., Ltd. Lubricant: Product name "Diamid 0-200T", manufactured by Nippon Kasei Co., Ltd. Carbon black: Intermediate Super Abrasion Furnace (ISAF) carbon black (product name "Show Black N220", manufactured by Cabot Japan) The values ​​for each component in Table 1 above are expressed in parts by weight.

[0069] As can be seen from Table 1, in the rubber composition containing EBDM, 30m 2 / g or more 150m 2 In Examples 1 to 8, in which silica having a CTAB specific surface area of ​​1×10 or less was blended in an amount of 25 to 90 parts by weight per 100 parts by weight of EBDM and a silane coupling agent was further blended, the rubber composition did not stick to the kneader surface in any case, stable kneading was possible, and kneading processability was excellent. In addition, the vulcanized molded products produced using the rubber compositions of Examples 1 to 8 had a TR-70 of -40°C or less and a volume resistivity of 1×10 12 The low temperature characteristics and electrical insulation properties were also excellent, since the compressive set ratio was Ω·cm or more. Furthermore, the vulcanized molded products produced using the rubber compositions of Examples 1 to 8 had a compression set ratio of 20% or less, indicating good compression set characteristics. In particular, Examples 1 to 2 and 4 to 6 showed excellent compression set characteristics.

[0070] On the other hand, 30m 2 / g or more 150m 2 In Comparative Example 1, in which the content of silica having a CTAB specific surface area of ​​1 / g or less was less than 30 parts by weight per 100 parts by weight of EBDM, the rubber composition adhered to the kneader surface, kneading could not be continued, and kneading processability was poor.

[0071] 30m 2 / g or more 150m 2 In Comparative Example 2, in which the content of silica having a CTAB specific surface area of ​​0.1 mg / g or less exceeded 90 parts by weight relative to 100 parts by weight of EBDM, the TR-70 of the vulcanized molded product produced using the rubber composition exceeded -40°C, and the low-temperature properties were poor.

[0072] CTAB specific surface area is 150m 2 In Comparative Examples 3 and 4, in which silica having a silica content exceeding 1 / g was used, the rubber composition adhered to the surface of the kneader, making it impossible to continue kneading, and the kneading processability was poor. In addition, the compression set rate exceeded 20%, and the compression set properties were also poor.

[0073] 30m 2 / g or more 150m 2 In Comparative Example 5, in which carbon black was used instead of silica having a CTAB specific surface area of ​​100 / g or less, the TR-70 of the vulcanized molded product produced using the rubber composition was higher than -40°C, and the specific volume resistivity was 1×10 12 Because the resistivity was less than Ω·cm, it was not possible to impart excellent low-temperature properties and electrical insulation to the vulcanized molded product. In addition, because a silane coupling agent was not used, the compression set rate exceeded 20%, and the compression set properties were also poor.

[0074] In Comparative Example 6, in which no silane coupling agent was used, the compression set rate of the vulcanized molded article produced using the rubber composition exceeded 20%, and it was not possible to impart good compression set properties to the vulcanized molded article.

[0075] In Comparative Example 7, in which EPDM was used instead of EBDM as the rubber component, the TR-70 of the vulcanized molded product produced using the rubber composition was above -40°C, and it was not possible to impart excellent low-temperature properties to the vulcanized molded product.

[0076] From the above results, in the rubber composition containing EBDM, 30m per 100 parts by weight of EBDM 2 / g or more 150m 2 It can be seen that by compounding silica having a specific surface area of ​​0.1 to 1.0 μm / g in the range of 25 parts by weight to 90 parts by weight, a rubber composition suitable for producing a vulcanization molded product having excellent kneading processability, good compression set characteristics, and excellent low-temperature characteristics and electrical insulation can be provided. Therefore, for example, when the vulcanization molded product is a seal part, such a seal part can exhibit excellent sealing performance in a low-temperature environment and is particularly suitable for use as a gasket for e-Mobility.

Claims

1. Ethylene-butene-diene terpolymer and 30m ２ / g or more 150m ２ / g or less, a silane coupling agent, and a crosslinking agent, the content of the silica relative to 100 parts by weight of the ethylene-butene-diene terpolymer is 25 parts by weight or more and 90 parts by weight or less; The ethylene-butene-diene terpolymer is an ethylene-butene-ethylidenenorbornene terpolymer, the crosslinking agent is an organic peroxide, The rubber composition, wherein the silane coupling agent is at least one selected from the group consisting of vinyl group-containing alkoxysilanes and amino group-containing alkoxysilanes.

2. The rubber composition according to claim 1, wherein the ethylene-butene-diene terpolymer has an iodine value of 3 or more and 20 or less.

3. 3. The rubber composition according to claim 1, wherein the content of the silane coupling agent relative to 100 parts by weight of the ethylene-butene-diene terpolymer is 0.5 parts by weight or more and 3.0 parts by weight or less.

4. A vulcanized molded product obtained by vulcanizing and molding the rubber composition according to any one of claims 1 to 3.

5. The vulcanization molded product according to claim 4, wherein the TR-70 value measured in accordance with JIS K6261:2006 is −40 ° C. or less.

6. The volume resistivity measured in accordance with JIS K6271-1:2015 is 1×10 １２ The vulcanization molded product according to claim 4 or 5, having a modulus of Ω·cm or more.

7. The vulcanization molded product according to any one of claims 4 to 6, having a compression set rate of 20% or less measured under conditions of 130 ° C. and 70 hours in accordance with JIS K6262:2013.

8. The vulcanization molded product according to any one of claims 4 to 7, which is a sealing part.

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