JP2022169892A - molding - Google Patents

Abstract

To provide a molding that prevents the electrolytic corrosion and degradation of a metal member even when used to be in contact with the metal member, and also has good moldability and is applicable to a thin-walled article.SOLUTION: A molding 1 is a vulcanizate of a rubber composition. The vulcanizate has a 50% modulus of 2.7 Mpa or more. The vulcanizate has a volume resistivity of 1×106 Ω cm or longer.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to molded bodies.

A vulcanized product of a rubber composition is sometimes used in contact with a metal member. For example, when the molding is a hose, it is used in contact with a fixing metal clamp. If the compact is in contact with the metal member, electricity may flow through the compact to the metal member, causing electrolytic corrosion and deterioration of the metal member.
Therefore, in order to suppress the electrolytic corrosion deterioration of metal members, techniques for improving the volume resistivity of the compact are being studied. For example, Patent Literature 1 discusses a technique of blending clay, which is an insulating filler.

JP 2012-72291 A

However, if the amount of clay compounded is increased, it is necessary to reduce the amount of carbon black compounded as a reinforcing material, and as a result, there is a risk that moldability will deteriorate.
The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a molded article that suppresses electrolytic corrosion deterioration of the metallic member even when used in contact with the metallic member and has good moldability. do.
The present disclosure can be implemented as the following forms.

A molded product that is a vulcanizate of a rubber composition,
50% modulus of the vulcanizate is 2.7 Mpa or more,
The molded article, wherein the vulcanizate has a volume resistivity value of 1×10 ⁶ Ω·cm or more.

Even if the molded article of the present disclosure is used so as to be in contact with a metallic member, deterioration of the metallic member due to electrolytic corrosion is suppressed, and the molded article has good formability.

1 is a perspective view showing an example of a molded body 1; FIG.

A preferred example of the present disclosure will now be presented.
[2] The molded article, wherein the vulcanizate has a hardness of 70 or more and 90 or less.
[3] The molded article, wherein the rubber composition contains ethylene-α-olefin-nonconjugated polyene copolymer rubber.
[4] The ethylene-α-olefin-nonconjugated polyene copolymer rubber is
containing ethylene units, α-olefin units, and non-conjugated polyene units,
When the sum of the ethylene unit content, the α-olefin unit content, and the non-conjugated polyene unit content is 100% by mass, the ethylene unit content is 60% by mass or more and 90% by mass. A molded body which is:
[5] The rubber composition contains an inorganic filler,
The molded article, wherein the content of the inorganic filler in the rubber composition is 15.0% by mass or more and 40.0% by mass or less.
[6] The rubber composition contains carbon black,
The molded article, wherein the content of the carbon black in the rubber composition is 20.0% by mass or more and 45.0% by mass or less.
[7] The molded body, wherein the ratio of the carbon black to the inorganic filler (the carbon black/the inorganic filler) is 0.70 or more and 1.40 or less by mass.
[8] A molded body having a hose shape.

The present disclosure will be described in detail below. In this specification, the description using "-" for the numerical range includes the lower limit and the upper limit unless otherwise specified. For example, the description “10 to 20” includes both the lower limit “10” and the upper limit “20”. That is, "10 to 20" has the same meaning as "10 or more and 20 or less".

1. molded body 1
Molded article 1 is a vulcanizate of a rubber composition. The molding 1 has a vulcanizate having a 50% modulus of 2.7 Mpa or more. The vulcanizate of the molded article has a volume resistivity value of 1×10 ⁶ Ω·cm or more. An example of a molded body 1 is shown in FIG. The shape of the molded body 1 is not particularly limited. The molded body 1 in FIG. 1 has a hose shape. This molded body 1 is an example of an air cleaner hose. An air cleaner hose is generally mounted in an engine room and has a function of guiding clean air that has passed through the air cleaner to the engine.

(1) Rubber composition (1.1) Rubber A rubber composition contains rubber (polymer). The type of rubber is not particularly limited. Preferred examples of rubber include ethylene-α-olefin-nonconjugated polyene copolymer rubber, acrylonitrile-butadiene copolymer, and chloroprene rubber. These rubbers may be used alone or in combination of two or more.

The rubber composition preferably contains ethylene-α-olefin-nonconjugated polyene copolymer rubber as the rubber.
The α-olefin of the ethylene-α-olefin-nonconjugated polyene copolymer rubber is not particularly limited. As α-olefins, α-olefins having 3 or more and 20 or less carbon atoms are preferably exemplified. Specific α-olefins include propylene, 1-butene, 1-pentene, 1-octene, 1-nonene, 1-decene, 1-undecene and the like. These α-olefins may be used alone or in combination of two or more. Preferred α-olefins are propylene, 1-butene, 1-hexene and 1-octene, with propylene being particularly preferred.
The non-conjugated polyene used in the ethylene-α-olefin-non-conjugated polyene copolymer rubber is not particularly limited. As the non-conjugated polyene, a non-conjugated polyene having 3 or more and 20 or less carbon atoms is preferably exemplified. Non-conjugated polyene specifically includes 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene and the like. These non-conjugated polyenes may be used alone or in combination of two or more.

Ethylene-α-olefin-nonconjugated polyene copolymer rubbers contain ethylene units, α-olefin units, and nonconjugated polyene units. "Ethylene unit" means a monomeric unit derived from ethylene. "α-olefin unit" means a monomeric unit derived from an α-olefin. "Non-conjugated polyene unit" means a monomeric unit derived from a non-conjugated polyene.
The content of ethylene units in the ethylene-α-olefin-nonconjugated polyene copolymer rubber is not particularly limited. The content of ethylene units may be included from the viewpoint of good moldability of the rubber composition, and the content of ethylene units, the content of α-olefin units, and the content of non-conjugated polyene units When the total is 100% by mass, it is greater than 0% by mass, preferably 60% by mass or more, more preferably 63% by mass or more, and even more preferably 68% by mass or more. On the other hand, the content of ethylene units is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. From these viewpoints, the content of ethylene units is preferably 60% by mass or more and 90% by mass or less, more preferably 63% by mass or more and 85% by mass or less, and even more preferably 68% by mass or more and 80% by mass or less. Those containing the above ethylene unit content are preferred.
When a plurality of ethylene-α-olefin-nonconjugated polyene copolymer rubbers having different ethylene unit contents are used, at least one ethylene-α-olefin-nonconjugated polyene copolymer rubber has ethylene units content is preferably within the above range.
The content of ethylene units is determined by the FTIR method according to ASTM D3900.

The content of non-conjugated polyene units in the ethylene-α-olefin-non-conjugated polyene copolymer rubber is not particularly limited. The content of non-conjugated polyene units is preferably 2% by mass or more when the total of the content of ethylene units, the content of α-olefin units, and the content of non-conjugated polyene units is 100% by mass. % by mass or more is more preferable, and 4% by mass or more is even more preferable. On the other hand, the content of non-conjugated polyene units is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. From these viewpoints, the content of the non-conjugated polyene unit is preferably 2% by mass or more and 15% by mass or less, more preferably 3% by mass or more and 10% by mass or less, and still more preferably 4% by mass or more and 5% by mass or less.
When a plurality of ethylene-α-olefin-nonconjugated polyene copolymer rubbers having different contents of non-conjugated polyene units are used, at least one ethylene-α-olefin-nonconjugated polyene copolymer rubber, The content of non-conjugated polyene units is preferably within the above range.
The content of non-conjugated polyene units is determined by the FTIR method according to ASTM D6047.

(1.2) Filler (1.2.1) Inorganic filler The rubber composition preferably contains an inorganic filler (excluding carbon black). When the rubber composition contains an inorganic filler, the volume resistivity of the molded article is improved, and electrolytic corrosion deterioration of the metal member can be suppressed.
The inorganic filler is not particularly limited. Examples of inorganic fillers include calcium carbonate, magnesium carbonate, aluminum hydroxide, calcium silicate, clay, talc, silica and the like. An inorganic filler may be used individually by 1 type, and may be used in combination of 2 or more types. Inorganic fillers are sometimes referred to as white fillers.
The content of the inorganic filler is not particularly limited. The content of the inorganic filler in the rubber composition is preferably 15.0% by mass or more, preferably 20.0% by mass, when the rubber composition is 100% by mass, from the viewpoint of improving the volume resistivity value of the molded article. % or more is more preferable, and 25.0% by mass or more is even more preferable. On the other hand, the inorganic filler is preferably 40.0% by mass or less, more preferably 35.0% by mass or less, and even more preferably 30.0% by mass or less, from the viewpoint of improving the moldability of the rubber composition. From these viewpoints, the content of the inorganic filler is preferably 15.0% by mass or more and 40.0% by mass or less, more preferably 20.0% by mass or more and 35.0% by mass or less, and 25.0% by mass or more. 30.0% by mass or less is more preferable.

(1.2.2) Carbon black The rubber composition preferably contains carbon black from the viewpoint of moldability of the rubber composition.
The type of carbon black is not particularly limited.カーボンブラックとしては、例えば、ＨＡＦ（Ｈｉｇｈ Ａｂｒａｓｉｏｎ Ｆｕｒｎａｃｅ）、ＳＡＦ（Ｓｕｐｅｒ Ａｂｒａｓｉｏｎ Ｆｕｒｎａｃｅ）、ＩＳＡＦ（Ｉｎｔｅｒｍｅｄｉａｔｅ ＳＡＦ）、ＩＳＡＦ－ＨＭ（Ｉｎｔｅｒｍｅｄｉａｔｅ ＳＡＦ－Ｈｉｇｈ Ｍｏｄｕｌｕｓ）、ＦＥＦ（Ｆａｓｔ Ｅｘｔｒｕｓｉｏｎ Ｆｕｒｎａｃｅ）、ＭＡＦ（Ｍｅｄｉｕｍ Ａｂｒａｓｉｏｎ Ｆｕｒｎａｃｅ ), GPF (General Purpose Furnace), and SRF (Semi-Reinforcing Furnace). Only one type of carbon black may be used, or two or more types may be used in combination.
The iodine adsorption amount (IA) of carbon black is not particularly limited. IA is a value measured according to JIS K6217-1:2008. When multiple types of carbon black are used, IA employs a value obtained by measuring a mixture of multiple types of carbon black as a sample. The iodine adsorption amount of carbon black is preferably 10 to 160 mg/g, more preferably 15 to 100 mg/g, even more preferably 20 to 50 mg/g.
The content of carbon black is not particularly limited. The content of carbon black in the rubber composition is preferably 20.0% by mass or more when the rubber composition is 100% by mass, from the viewpoint of improving moldability even for thin-walled articles. 0% by mass or more is more preferable, and 28.0% by mass or more is even more preferable. On the other hand, carbon black is preferably 45.0% by mass or less, more preferably 40.0% by mass or less, and even more preferably 35.0% by mass or less, from the viewpoint of suppressing electrolytic corrosion deterioration of metal members. From these viewpoints, the content of carbon black is preferably 20.0% by mass or more and 45.0% by mass or less, more preferably 24.0% by mass or more and 40.0% by mass or less, and 28.0% by mass or more and 35% by mass. 0% by mass or less is more preferable.

(1.2.3) Ratio of Carbon Black to Inorganic Filler The ratio of carbon black to the inorganic filler is not particularly limited.
The ratio of carbon black to the inorganic filler (carbon black/inorganic filler) is preferably 0.70 or more and 1.50 or less, more preferably 0.90 or more and 1.40 or less, in mass ratio, It is more preferably 1.00 or more and 1.30 or less. Within this range, even if the molded article is used so as to be in contact with the metal member, the electrolytic corrosion deterioration of the metal member is suppressed, and the moldability of the rubber composition is improved.

(1.2.4) Total amount of inorganic filler and carbon black The total amount of the inorganic filler (excluding carbon black) and carbon black is not particularly limited. The total amount is preferably 150 parts by mass or more and 300 parts by mass or less, more preferably 180 parts by mass or more and 250 parts by mass or less, when rubber is 100 parts by mass.

(1.3) Other compounding materials In addition to the rubber and filler, the rubber composition is appropriately compounded with a softening agent, a vulcanizing agent, a vulcanization accelerator, a cross-linking aid, etc., as necessary. I don't mind. These are used alone or in combination of two or more.

(1.3.1) Softener The softener is not particularly limited. Examples of softening agents include fatty acids such as stearic acid and esters thereof, fatty acid metal salts such as zinc stearate and calcium stearate, glycols such as polyethylene glycol, process oils, lubricating oils, paraffin, petroleum asphalt, castor oil, factice, and the like. is mentioned. You may use a softening agent individually or in combination of 2 or more types.
The content of the softening agent is not particularly limited. The content of the softening agent is preferably 20 parts by mass or more and 120 parts by mass or less from the viewpoint of ensuring the hardness of the vulcanizate while maintaining the workability when the rubber is 100 parts by mass.

(1.3.2) Vulcanizing agent As the vulcanizing agent, for example, sulfur, organic peroxide (peroxide vulcanizing agent) and the like are preferably used. You may use a softening agent individually or in combination of 2 or more types.

(1.3.2.1) Sulfur Sulfur is not particularly limited. As sulfur, for example, powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, etc. are preferably used.
The compounding amount of sulfur is not particularly limited. The amount of sulfur compounded is 0.3 parts by mass or more and 5.0 parts by mass or less from the viewpoint of moderately progressing vulcanization and suppressing the occurrence of bloom after vulcanization when rubber is 100 parts by mass. is preferred.

(1.3.2.2) Organic Peroxide The organic peroxide is not particularly limited. Examples of organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-(t-butylperoxy)hexyne-3, di-t-butylperoxide, di-t-butylperoxide-3,3,5-trimethyl cyclohexane, 1,3-bis(t -Butylperoxyisopropyl)benzene and the like. You may use an organic peroxide individually or in combination of 2 or more types.

(1.3.2.3) Crosslinked morphology
Preferred forms of cross-linking include sulfur-based cross-linking, resin-based cross-linking, and organic peroxide-based cross-linking. The crosslinked forms may be used singly or in combination of two or more.

(1.3.3) Vulcanization Accelerator Examples of vulcanization accelerators when sulfur is used include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and dipentamethylenethiuram. monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiuram tetrasulfide, N,N'-dimethyl-N,N'-diphenylthiuram disulfide, N,N'-dioctadecyl-N,N'-diisopropylthiuram disulfide, N -cyclohexyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide, N,N-diisopropyl-2-benzothiazolylsulfenamide, 2-mercaptobenzothiazole, 2-( 2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl-4-morpholinothio)benzothiazole, dibenzothiazyl-disulfide, diphenylguanidine, triphenylguanidine, acetaldehyde-aniline reactant, butyraldehyde- Aniline condensate, hexamethylenetetramine, acetaldehyde ammonia, 2-mercaptoimidazoline, diethylthiourea, dibutylthiourea, trimethylthiourea, di-o-tolylthiourea, zinc dimethyldithiocarbamate, zinc diethylthiocarbamate, di-n-butyldithiocarbamine zinc acid, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, tellurium diethyldithiocarbamate, zinc dibutylxanthate and the like. Vulcanization accelerators may be used alone or in combination of two or more. It is desirable to use two or more vulcanization accelerators in combination. The amount of the vulcanization accelerator to be blended is preferably determined appropriately according to the required physical properties. The amount of the vulcanization accelerator compounded is 2 parts by mass or more and 8 parts by mass or less from the viewpoint of moderately progressing vulcanization and suppressing the occurrence of bloom after vulcanization when rubber is 100 parts by mass. preferable.

(1.3.4) Cross-linking Aids Examples of cross-linking aids when using an organic peroxide include p,p'-dibenzoylquinonedioxime, triallyl isocyanurate, N,N'-m- Phenylene bismaleimide, methyl methacrylate, ethyl methacrylate, propyl methacrylate, benzyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, methacryloxyethyl phosphate, 1,4-butanediol diacrylate, ethylene glycol dimethacrylate, 1,3-butylene glycol Dimethacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, allyl glycidyl ether, N-methylol methacrylamide, zinc methacrylate, methacryl calcium acid, magnesium methacrylate, and the like. A cross-linking aid may be used alone or in combination of two or more.

(1.3.5) Paraffinic process oil The rubber composition may contain a paraffinic process oil.
A commercially available paraffinic process oil can be used. Commercially available products include, for example, Idemitsu Kosan Diana Process Oil "PS-430", "PS-32", "PS-90", "PW-32", "PW-90", "PW-150", " PW-380” and the like.
The amount of paraffinic process oil is not particularly limited. The amount of the paraffin-based process oil compounded is preferably 10 parts by mass or more and 50 parts by mass or less, more preferably 20 parts by mass or more and 40 parts by mass or less, based on 100 parts by mass of rubber.

(1.3.6) Compounding materials other than the above The rubber composition may also contain antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, pigments, foaming agents, etc., if necessary.

(1.4) Mooney Viscosity of Rubber Composition (Uncrosslinked Rubber) The Mooney viscosity [ML(1+4) 125°C] of the uncrosslinked rubber composition is preferably 60 or less from the viewpoint of moldability. The Mooney viscosity [ML(1+4) 125°C] of the uncrosslinked rubber composition is usually 50 or more.
Mooney viscosity (ML(1+4) 125°C) is measured at 125°C using a Mooney viscometer (Model SMV 300 manufactured by Shimadzu Corporation) in accordance with JIS K6300. At this time, ML(1+4) 125° C. after 5 minutes from the start of measurement is obtained.

(2) Properties of vulcanizate of rubber composition (2.1) 50% modulus The 50% modulus of the vulcanizate is 2.7 Mpa or more from the viewpoint of sufficiently securing the strength of thin-walled articles. , preferably 2.8 Mpa or more, more preferably 2.9 Mpa or more. The 50% modulus of the vulcanizate is usually 5 Mpa or less.
A method for measuring the 50% modulus is as follows. A No. 3 dumbbell test piece described in JIS K6251 is prepared by punching a vulcanized rubber sheet. Using this test piece and a tensile tester (AGS-1kNX manufactured by Shimadzu Corporation), according to the method specified in JIS K6251, the measurement temperature is 25 ° C. and the tensile speed is 500 mm / min. Measure.

(2.2) Volume Specific Resistance Value The volume specific resistance value of the vulcanizate is 1×10 ⁶ Ω·cm or more, and 1×10 ⁷ Ω·cm or more, from the viewpoint of suppressing electrolytic corrosion deterioration of metal members. is preferable, and 1×10 ⁸ Ω·cm or more is more preferable. The volume resistivity of the vulcanizate is usually 1×10 ¹¹ Ω·cm or less.
According to JIS K6271, the volume resistivity value was measured using a 2 mm × 100 mm × 100 mm vulcanized rubber sheet (vulcanized sheet) with a smooth surface and an ammeter (advantest electrometer R8340). A rubber sheet) is sandwiched between metal electrodes, and the specific volume resistivity is measured under the conditions of 25° C. and 1 V.

(2.3) Hardness The hardness of the vulcanizate is preferably 70 or more and 90 or less, more preferably 75 or more and 85 or less, and even more preferably 77 or more and 83 or less, from the viewpoint of application to thin-walled articles.
If the hardness is within this range, for example, even if the hose shape is used, it can withstand pressure changes such as negative pressure, so it is suitable for air cleaner hoses and the like.
Hardness (A hardness) is measured according to JIS K6253. That is, the hardness of the sheet (type A durometer, HA) is measured using three 2 mm vulcanized rubber sheets (vulcanized sheets) having a smooth surface, and stacking the flat parts to a thickness of about 6 mm. conduct.

2. Method for Manufacturing Molded Body 1 The method for manufacturing molded body 1 is not particularly limited.
The molded body 1 is manufactured, for example, as follows.
(1) Preparation of rubber composition A rubber composition is prepared by blending predetermined amounts of filler, softening agent, etc. with rubber (polymer). After that, the rubber compound is kneaded by a twin-screw kneader such as a mixer, and a vulcanizing agent and a vulcanization accelerator are added to prepare a rubber composition.
(2) Production of molded article 1 The molded article 1 can be produced by molding the rubber composition into a predetermined shape and then vulcanizing it at a predetermined temperature.
In addition, when the molding 1 has a hose shape, the thickness is not particularly limited. In the case of a hose shape, the maximum thickness of the molded body 1 can be, for example, 2.0 mm or more and 5.0 mm or less.

Hereinafter, more specific description will be given with reference to examples.

1. Preparation of molded body (Example 1-4 and Comparative Example 1-2)
Various moldings were produced at the blending ratios shown in Table 1-3. In Table 1, details of the main raw materials are shown below.

(1) Main raw materials (1.1) Ethylene-α-olefin-nonconjugated polyene copolymer rubber The following polymer was used as the ethylene-α-olefin-nonconjugated polyene copolymer rubber. Since Polymer C contains a polymer content and an oil content, Table 1 shows the amounts of both (polymer content and oil content) separately.
・Polymer A: EPDM Keltan 2650 LANXESS Non-conjugated polyene unit content 6% by mass, ethylene unit content 53% by mass
-Polymer B: EPDM EPT3092M Mitsui Chemicals, Inc. Content of non-conjugated polyene unit 5% by mass, content of ethylene unit 65% by mass
・Polymer C: EPDM Esprene 600F manufactured by Sumitomo Chemical Co., Ltd. Content of non-conjugated polyene units: 4% by mass, content of ethylene units: 66% by mass
Oil content of polymer C: paraffin oil Polymer C contains 50% by mass of polymer and 50% by mass of oil.
・Polymer D: EPDM NORDEL IP4725P Dow Chemical Non-conjugated polyene unit content 5% by mass, ethylene unit content 70% by mass
・Polymer E: EPDM K9720 Mitsui Chemicals, Inc. Content of non-conjugated polyene units: 10% by mass, content of ethylene units: 77% by mass

(1.2) Carbon black/Carbon black FEF: Asahi #60UG (FEF) Asahi Carbon Co., Ltd. Iodine adsorption amount IA 41 mg / g
・ Carbon black SRF: Asahi #50G (SRF) manufactured by Asahi Carbon Co., Ltd., iodine adsorption amount IA 27 mg / g
(1.3) Inorganic filler/white filler: Burgess KE Burgess Pigment
_Birkes KE is a clay ₍ 1.4) paraffinic process oil ₍ abbreviated as "process oil" in the description)
· Process oil: Diana Process PS-430, manufactured by Idemitsu Kosan Co., Ltd. (1.5) Common small amount compounding materials In all samples, the following materials were blended.
・2 types of zinc oxide: 5.00 parts by mass (phr) manufactured by Haku Sui Tech Co., Ltd. ・Stearic acid: 1.00 parts by mass (phr) manufactured by NOF Corporation ・PEG#4000: 2.00 parts by mass (phr) Co., Ltd. Manufactured by Adeka, Hytanol 1501: 1.50 parts by mass (phr) Structol WB-16, manufactured by Hitachi Chemical Co., Ltd.: 0.20 parts by mass (phr), manufactured by S&S Co., Ltd., Rhenogran CBS-80 (N-cyclohexyl-2) --Benzothiazylsulfenamide): 2.13 parts by mass (phr) Lanxess Rhenogran ZDBC-80 (zinc dibutyldithiocarbamate): 1.25 parts by mass (phr) Lanxess Sanmix TT-75 (Thiam-based vulcanization accelerator): 0.76 parts by mass (phr) Sanshin Chemical Industry Co., Ltd. Sanmix TRA-70 (thiuram-based vulcanization accelerator): 0.71 parts by mass (phr) Sanshin Chemical Industry Co., Ltd. Rhenogran S-80 (sulfur): 0.75 parts by mass (phr) Lanxess Barnok R (4,4'-dithiodimorpholine): 1.50 parts by mass (phr) Ouchi Shinko Kagaku Kogyo Co., Ltd. company made

The total amount of carbon black (parts by mass) means the total amount of carbon black FEF and carbon black SRF.
The total amount (% by mass) of carbon black is the ratio of the total amount (parts by mass) of carbon black to the total amount (parts by mass) of the composition. This ratio corresponds to the carbon black content (% by mass) of the present disclosure.
White filler (% by mass) is the ratio of white filler (parts by mass) to the total amount (parts by mass) of the composition. This ratio corresponds to the content (% by mass) of the inorganic filler of the present disclosure.
The carbon black/white filler ratio (mass ratio) corresponds to the carbon black/inorganic filler mass ratio of the present disclosure.
The total amount of filler is the total amount of carbon black and white filler.
The total amount of oil (parts by mass) is the total amount of the oil content of polymer C and the paraffinic process oil.
The total amount of oil (% by mass) is the ratio of the total amount of oil (parts by mass) to the total amount (parts by mass) of the composition.

(2) Production of Molded Body Specifically, the molded body was produced as follows.
A rubber compound was prepared by compounding predetermined amounts of carbon black, a white filler, a softening agent, and the like into the polymer. Thereafter, this compound was kneaded by a twin-screw kneader such as a mixer (discharge temperature: 100°C, number of revolutions: 25 rpm), and a vulcanizing agent and a vulcanization accelerator were added using an 8-inch roll to prepare a rubber composition. After molding and processing the rubber composition into a shape suitable for the test method, it was vulcanized at 170° C. for 10 minutes to obtain a vulcanized rubber molding.

2. Evaluation method The Mooney viscosity of the rubber composition (uncrosslinked rubber) was measured by the method described in the section "(1) Rubber composition (1.4) Mooney viscosity of rubber composition (uncrosslinked rubber)".
The 50% modulus, volume resistivity and hardness of the vulcanizates were measured by the methods described in the section "(2) Properties of vulcanizates of rubber compositions".

3. Results The results are also shown in Table 1.
(1) Mooney viscosity (ML (1+4) 125°C)
In Table 1, A in the Mooney viscosity column means the following.
A: The Mooney viscosity is 60 or less, and the moldability of the unvulcanized rubber composition is good.
(2) Hardness In Table 1, A and B in the column of hardness mean the following.
A: It has a hardness of 70 to 90 and is applicable to thin-walled articles.
B: Hardness is less than 70, unsuitable for thin-walled articles.
(3) 50% modulus In Table 1, A and B in the column of 50% modulus mean the following.
A: It has a 50% modulus of 2.7 or more and is applicable to thin-walled articles.
B: 50% modulus is less than 2.7, unsuitable for thin-walled articles.
(4) Volume specific resistance value In Table 1, A and B in the volume specific resistance column mean the following.
A: The volume resistivity value is 1.0×10 ⁶ Ω·cm or more, and even when used in contact with a metal member, electrolytic corrosion deterioration of the metal member is suppressed.
B: The volume resistivity value is less than 1.0×10 ⁶ Ω·cm, and when used in contact with a metal member, the metal member is deteriorated by electrolytic corrosion.
(5) Comprehensive Judgment In Table 1, "OK" and "NG" in the comprehensive judgment column mean the following.
OK: The moldability of the unvulcanized rubber composition is good, and the properties of the vulcanizate are also good.
NG: Poor properties of the vulcanizate.

(6) Satisfaction Status of Each Requirement of Example 1-4 Example 1-4 satisfies all of the following requirements (a) to (h).
- Requirement (a): The 50% modulus of the vulcanizate is 2.7 Mpa or more.
• Requirement (b): The volume resistivity of the vulcanizate is 1×10 ⁶ Ω·cm or more.
Requirement (c): The hardness of the vulcanizate is 70-90.
Requirement (d): The rubber composition contains ethylene-α-olefin-nonconjugated polyene copolymer rubber.
Requirement (e): The content of ethylene units in the ethylene-α-olefin-nonconjugated polyene copolymer rubber is 60% by mass or more and 90% by mass or less.
- Requirement (f): An inorganic filler is contained, and the content of the inorganic filler is 15.0% by mass or more and 40.0% by mass or less.
- Requirement (g): Carbon black is contained, and the content of carbon black is 20.0% by mass or more and 45.0% by mass or less.
Requirement (h): The ratio of carbon black to the inorganic filler (carbon black/inorganic filler) is 0.70 or more and 1.40 or less in mass ratio.

(7) Satisfaction status of each requirement of Comparative Example 1-3 On the other hand, Comparative Example 1-3 does not satisfy the following requirements.
Comparative Example 1 does not satisfy the requirements (b), (f), (g), and (h).
Comparative Example 2 does not satisfy the requirements (a) and (c).
Comparative Example 3 does not satisfy the requirements (a) and (c).

(8) Results and Discussion Examples 1-4 were evaluated as good overall. That is, in Examples 1-4, the moldability of the unvulcanized rubber composition was good, and the properties of the vulcanizates were also good.
On the other hand, in Comparative Example 1, which does not contain an inorganic filler (white filler), the volume resistivity of the vulcanizate was low, and the comprehensive judgment was also unsatisfactory.
In Comparative Example 2, the 50% modulus of the vulcanizate was low, the hardness of the vulcanizate was low, and the overall evaluation was poor.
In Comparative Example 3, the 50% modulus of the vulcanizate was low, the hardness of the vulcanizate was low, and the overall evaluation was also poor. In Comparative Example 3, 50 parts by mass of EPDM (Polymer A) with a low ethylene unit content of 53% by mass was used in 100 parts by mass of EPDM, and the overall judgment was unsatisfactory. Therefore, it is preferable that more than 50 parts by mass of EPDM used as a raw material have an ethylene unit content of 60% by mass or more and 90% by mass or less.

4. Effect of Examples In Examples 1-4, even when used in contact with a metal member, electrolytic corrosion deterioration of the metal member is suppressed, moldability is good, and it is applicable to thin-walled articles.

The present disclosure is not limited to the embodiments detailed above, and various modifications or alterations are possible.

1... molded body

Claims (8)

A molded product that is a vulcanizate of a rubber composition,
50% modulus of the vulcanizate is 2.7 Mpa or more,
The molded article, wherein the vulcanizate has a volume resistivity value of 1×10 ⁶ Ω·cm or more. The molded article according to claim 1, wherein the vulcanizate has a hardness of 70 or more and 90 or less. 3. The molded article according to claim 1, wherein the rubber composition contains ethylene-α-olefin-nonconjugated polyene copolymer rubber. The ethylene-α-olefin-nonconjugated polyene copolymer rubber is
containing ethylene units, α-olefin units, and non-conjugated polyene units,
When the sum of the ethylene unit content, the α-olefin unit content, and the non-conjugated polyene unit content is 100% by mass, the ethylene unit content is 60% by mass or more and 90% by mass. The molded article according to claim 3, wherein: The rubber composition contains an inorganic filler,
The molded article according to any one of claims 1 to 4, wherein the content of the inorganic filler in the rubber composition is 15.0% by mass or more and 40.0% by mass or less. The rubber composition contains carbon black,
The molded article according to claim 5, wherein the carbon black content in the rubber composition is 20.0% by mass or more and 45.0% by mass or less. 7. The molded article according to claim 6, wherein the ratio of the carbon black to the inorganic filler (the carbon black/the inorganic filler) is 0.70 or more and 1.40 or less by mass. 8. The molded body according to any one of claims 1 to 7, which has a hose shape.

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