Sealing material and method for manufacturing a sealing material

Abstract

An embodiment of the present application relates to a sealing material or a method for producing a sealing material, the sealing material being a radiation crosslinked body of an elastomer composition containing a crosslinkable fluorine-containing elastomer (A) other than a perfluoroelastomer, a crosslinking agent, and a crosslinking coagent, wherein the crosslinkable fluorine-containing elastomer (A) contains a crosslinkable fluorine-containing elastomer (A1) other than a perfluoroelastomer having a fluorine content in the range of 66 to 68 mass%.

Description

TECHNICAL FIELD

[0001] One embodiment of the present application relates to a sealing material or a method for producing a sealing material. BACKGROUND

[0002] Conventionally, sealing materials have been widely used for various purposes, and as an example of a use of a sealing material to which a large load is applied, a sealing material used in a semiconductor manufacturing apparatus or the like can be given.

[0003] As such a sealing material, in order to be able to obtain a sealing material having excellent plasma resistance or radical resistance, a cross-linkable fluorine-containing elastomer is used.

[0004] A sealing material made of such a cross-linkable fluorine-containing elastomer is generally made using an elastomer composition obtained by blending additives such as a cross-linking agent, a cross-linking aid, or the like in the cross-linkable fluorine-containing elastomer, and by shaping and cross-linking the elastomer composition to be used as a sealing material. In particular, from the viewpoint of the crack resistance and the sealing property of the obtained sealing material, cross-linking including a step of irradiating a radiation is performed at the time of cross-linking (for example, see Patent Document 1).

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-131656 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] As described above, when an additive is blended in a cross-linkable fluorine-containing elastomer to form an elastomer composition, in order to produce a sealing material exhibiting desired properties from the elastomer composition, it is necessary to uniformly mix each component in the elastomer composition.

[0010] However, in the case of using a conventional cross-linkable fluorine-containing elastomer, particularly in the case of using a liquid or oil component, a long time is required to prepare such a uniform elastomer composition, and there is room for improvement in this regard.

[0011] In addition, when a sealing material is formed from the produced elastomer composition at a high production rate, the elastomer composition is generally made into a sheet material by a sheeting process. The sheeting process is generally performed by passing the elastomer composition between rollers, but in the case of using a conventional elastomer composition, the elastomer composition is sometimes not bitten between the rollers or cannot be smoothly wound onto the rollers, so it is not easy to make a sheet material (poor sheeting property). Therefore, there is room for improvement in the formability of the conventional elastomer composition.

[0012] Further, the sealing material formed from the existing elastomer composition has room for improvement in terms of properties as a sealing material such as tensile strength and elongation at break.

[0013] An embodiment of the present application provides a sealing material that can be manufactured with excellent formability, has good sealing properties, and has high tensile strength and elongation at break.

[0014] Technical solution adopted to solve the technical problem

[0015] The present inventors have conducted intensive studies in order to solve the above technical problem, and as a result, have found that the above problem can be solved by the following configuration example, thereby completing the present application.

[0016] The configuration of the present application is, for example, as described below.

[0017] [1] A sealing material which is a radiation crosslinked body of an elastomer composition containing a crosslinkable fluorine-containing elastomer (A) other than a perfluoroelastomer, a crosslinking agent, and a crosslinking aid, wherein the crosslinkable fluorine-containing elastomer (A) contains a crosslinkable fluorine-containing elastomer (Al) other than a perfluoroelastomer having a fluorine content in the range of 66 to 68 mass%.

[0018] [2] The sealing material according to [1], wherein the fluorine-containing elastomer (A) is a peroxide-crosslinkable fluorine-containing elastomer.

[0019] [3] The sealing material according to [1] or [2], wherein the elastomer composition contains at least one compound containing an ethylenic unsaturated bond selected from a compound having a perfluoro skeleton with an ethylenic unsaturated bond and a compound having a siloxane skeleton with an ethylenic unsaturated bond.

[0020] [4] The elastomer composition according to any one of [1] to [3], wherein the content of a filler material is 5 mass% or less with respect to 100 mass parts of the fluorine-containing elastomer (A).

[0021] [5] A method for manufacturing a sealing material, comprising a step of irradiating a radiation to an elastomer composition containing a crosslinkable fluorine-containing elastomer (A) other than a perfluoroelastomer, a crosslinking agent, and a crosslinking aid, and the crosslinkable fluorine-containing elastomer (A) contains a crosslinkable fluorine-containing elastomer (Al) other than a perfluoroelastomer having a fluorine content in the range of 66 to 68 mass%, or a crosslinked body of the elastomer composition.

[0022] Effects of the invention

[0023] According to one embodiment of the present application, a sealing material that can be manufactured with excellent formability, has good sealing properties (small compression set), and has a large tensile strength and elongation at break can be provided. Specifically, a sealing material that has good sealing properties and a large tensile strength and elongation at break can be provided from an elastomer composition that has excellent formability, particularly excellent tabletability, and that can be formed into a uniform elastomer composition in a short time.

[0024] Further, according to one embodiment of the present application, a sealing material that exhibits excellent hardness, tensile strength, elongation at break, and tensile stress at 100% elongation (100% Mo) in a good balance and that has excellent plasma resistance (free radical resistance), crack resistance, and compression set can be obtained. Therefore, the sealing material is suitable as a sealing material for a semiconductor manufacturing device, a sealing material for a plasma processing device. DETAILED DESCRIPTION

[0025] Sealing Material

[0026] The sealing material of one embodiment of the present application (hereinafter also referred to as "the present sealing material") is a radiation crosslinked body of an elastomer composition (hereinafter also referred to as "the present composition") including a crosslinkable fluorine-containing elastomer (A) other than a perfluoroelastomer, a crosslinking agent, and a crosslinking aid, the crosslinkable fluorine-containing elastomer (A) including a crosslinkable fluorine-containing elastomer (Al) other than a perfluoroelastomer having a fluorine content in the range of 66 to 68 mass%.

[0027] The radiation crosslinked body of the present composition can be specifically exemplified by the present composition itself, or a radiation crosslinked body obtained by a method including a step of irradiating radiation to a crosslinked product of the present composition (e.g., a crosslinked product obtained by heat-crosslinking the present composition).

[0028] The present sealing material can be used, for example, as a gasket or a seal ring for various members, and is particularly suitable for use in a semiconductor manufacturing device, a plasma processing device, and particularly a driving portion typified by a gate valve used for an opening portion of a plasma processing chamber unit, because of the above-described effects.

[0029] The shape and the like of the present sealing material can be appropriately selected according to the use.

[0030] The present sealing material can be a sealing material that does not include a filler and has the following properties.

[0031] The Shore A hardness (type A durometer hardness) of the present sealing material, which is measured in accordance with JIS K 6253:2012, is preferably 60 or more.

[0032] The tensile strength of the present sealing material, which is measured in accordance with JIS K 6251:2017, is preferably 10 MPa or more.

[0033] The elongation at break of the sealing material of the present application is preferably 130% or more as measured according to JIS K 6251:2017.

[0034] The 100% Mo of the sealing material of the present application is preferably 3.5 MPa or more as measured according to JIS K 6251:2017.

[0035] The compression set of the sealing material of the present application is preferably 35% or less as measured according to JIS K 6262:2013.

[0036] <Fluorine-containing elastomer (A) other than perfluoroelastomer>

[0037] The elastomer (A) can contain a cross-linkable fluorine-containing elastomer (A1) other than perfluoroelastomer having a fluorine content in the range of 66 to 68 mass% without particular limitation.

[0038] The elastomer (A) can be used in one kind, or two or more kinds, and the elastomer (A1) can also be used in one kind, or two or more kinds.

[0039] In the present application, "elastomer" and "rubber" are synonymous, and they are not particularly distinguished.

[0040] The cross-linkable fluorine-containing elastomer (A) can also contain another cross-linkable fluorine-containing elastomer other than perfluoroelastomer (hereinafter also referred to as "elastomer (A2)") other than the elastomer (A1), and it is preferable to contain the elastomer (A2) from the viewpoint of being able to easily obtain a sealing material having excellent plasma resistance, chemical resistance, and the like.

[0041] In the case where the elastomer (A) contains the elastomer (A2), the elastomer (A2) can be used in one kind, or two or more kinds.

[0042] The elastomer (A) is also referred to as unvulcanized fluororubber, and as a cross-linking type, peroxide cross-linking, polyol cross-linking, amine cross-linking, radiation cross-linking type, and the like can be exemplified. Among them, from the aspect that it is not necessary to use an acid-adsorbing agent which becomes a particle generation source in a plasma atmosphere or the like, and there is no risk of particle generation in the obtained sealing material during use, a peroxide-cross-linkable fluorine-containing elastomer is preferable.

[0043] As a specific example of the elastomer (A), a fluorine-containing elastomer (FKM), a tetrafluoroethylene-propylene-based elastomer (FEPM), a fluorine-based thermoplastic elastomer (for example, an elastomer containing at least one elastomeric polymer chain segment and at least one non-elastomeric polymer chain segment, and at least one of them is a fluoropolymer chain segment) can be exemplified.

[0044] As the elastomer (A), an elastomer from which a sealing material exhibiting resistance to plasma (plasma etching treatment) used in various semiconductor dry processes can be obtained is preferred, and a FKM which is excellent in plasma resistance and sealing performance is more preferred. In addition, a FKM is also preferred in terms of cost and versatility.

[0045] As the elastomer (A), a product synthesized by a conventionally known method can be used, and a commercially available product can also be used. As the commercially available product, "DAI-EL" manufactured by Daikin Industries, Ltd., "Viton" manufactured by Chemours, "Dyneon" manufactured by 3M Company, and "Technoflon" manufactured by Solvay can be exemplified.

[0046] The fluorine content of the elastomer (Al) is 66 to 68 mass %.

[0047] The fluorine content of the elastomer (A2) is not particularly limited as long as it is in a range other than 66 to 68 mass %, and from the viewpoint of being able to easily obtain a sealing material which is excellent in plasma resistance, chemical resistance, and the like, it is preferred to be 69 mass % or more, more preferred to be 70 mass % or more, more preferred to be 73 mass % or less, and further preferred to be 71 mass % or less.

[0048] By using at least two kinds of elastomers having a fluorine content in the above range, a uniform elastomer composition can be obtained in a short time, and an elastomer composition which is excellent in moldability can be easily obtained, and a sealing material which is excellent in hardness, tensile strength, elongation at break, and 100% Mo in a good balance can be easily obtained.

[0049] The fluorine content can be determined and calculated by fluorine element analysis or mass spectrometry (MS spectrometry) using 19 F-NMR, 1 H-NMR, or the like.

[0050] The fluorine content in the present application is a value obtained by rounding off the decimal point.

[0051] The Mooney viscosity of the elastomer (A) is preferably 10 or more, more preferably 15 or more, further preferably 20 or more, preferably 140 or less, more preferably 120 or less, further preferably 80 or less, and particularly preferably 60 or less.

[0052] If the Mooney viscosity of the elastomer (A) is in the above range, an elastomer composition which is excellent in moldability, particularly tabletting property, can be easily obtained.

[0053] In addition, the Mooney viscosity in the present specification refers to the Mooney viscosity (ML1+10) at 121°C determined according to ASTM D 1646.

[0054] As an example of the elastomer (A2), an elastomer (A2-1) having a Mooney viscosity preferably in the range of 40 to 140, more preferably in the range of 40 to 120, further preferably in the range of 40 to 60 and an elastomer (A2-2) having a Mooney viscosity preferably in the range of 10 or more and less than 40, more preferably in the range of 10 to 30 are preferably used.

[0055] By using the elastomers (A2-1) and (A2-2), the resulting sealing material can exhibit excellent hardness, tensile strength, elongation at break, 100% Mo and other general properties and formability, particularly tabletability, of the elastomer composition in a better balance.

[0056] In the case where the elastomers (A2-1) and (A2-2) are used as the elastomer (A2), the content of the elastomer (A2-1) is preferably in the range of 20 to 80% by mass, relative to 100% by mass of the total thereof.

[0057] If the content of the elastomer (A2-1) is in the above range, the resulting sealing material can exhibit excellent hardness, tensile strength, elongation at break, 100% Mo and other general properties and formability, particularly tabletability, of the elastomer composition in a better balance, and thus is preferred.

[0058] In the case where the elastomer (A) is formed only of the elastomer (Al), the content of the elastomer (Al) in the solid components of the present composition is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 97% by mass or less, further preferably 95% by mass or less.

[0059] If the content of the elastomer (Al) is in the above range, a sealing material having excellent sealing properties, formability and chemical resistance can be easily obtained.

[0060] In the present specification, the solid components refer to components other than solvents.

[0061] In the case where the elastomer (A) contains the elastomer (A2), the content of the elastomer (Al) in the solid components of the present composition is preferably 2% by mass or more, more preferably 5% by mass or more, and preferably 50% by mass or less, further preferably 40% by mass or less.

[0062] If the content of the elastomer (Al) is in the above range, a sealing material exhibiting excellent formability and chemical resistance in a good balance can be easily obtained.

[0063] In the case where the elastomer (A) contains the elastomer (A2), the content of the elastomer (A2) in the solid content of the present composition is preferably 40% by mass or more, more preferably 50% by mass or more, and preferably 95% by mass or less, further preferably 85% by mass or less.

[0064] If the content of the elastomer (A2) is within the above range, a sealing material that exhibits excellent formability and chemical resistance, etc. in a good balance can be easily obtained.

[0065] In the case where the elastomer (A) contains the elastomer (A2), the content of the elastomer (A1) with respect to the total content of the elastomers (A1) and (A2) in the present composition is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less.

[0066] If the mass ratio of the contents of the elastomers (A1) and (A2) is within the above range, a sealing material that exhibits excellent formability and chemical resistance, etc. in a good balance can be easily obtained.

[0067] [FKM]

[0068] The FKM is not particularly limited, and a polymer containing a hydrogen atom (carbon-hydrogen bond) in the polymer main chain can be exemplified, and specifically, a structure unit derived from vinylidene fluoride is preferably contained.

[0069] The FKM is not particularly limited, and as specific examples, a vinylidene fluoride-hexafluoropropylene polymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene polymer, a vinylidene fluoride-propylene-tetrafluoroethylene polymer, an ethylene-tetrafluoroethylene-perfluoroalkyl vinyl ether polymer, and a vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether polymer can be exemplified.

[0070] As a preferable example of the perfluoroalkyl vinyl ether, a perfluoromethyl vinyl ether can be exemplified.

[0071] Among them, from the viewpoint of excellent plasma resistance, heat resistance, chemical resistance, etc., a terpolymer is preferable, and a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene polymer is more preferable.

[0072] The peroxide-crosslinkable fluorine-containing elastomer preferably has a functional group such as an iodine group, a bromine group, a cyano group, a peroxide group, and an unsaturated group. From the viewpoint of easiness of introduction of the functional group, an iodine group and a bromine group are more preferable.

[0073] The fluorine-containing elastomer having an iodine group and / or a bromine group can be obtained, for example, by using one or more saturated or unsaturated iodine-containing and / or bromine-containing compounds at the time of synthesis of the elastomer.

[0074] As the iodine- and / or bromine-containing compound, for example, a compound represented by the following formula (1) or (2) can be exemplified.

[0075] By using a compound represented by the following formula (1), a fluorine-containing elastomer having an iodine group and / or a bromine group in a side chain can be synthesized, and by using a compound represented by the following formula (2), a fluorine-containing elastomer having an iodine group and / or a bromine group at a terminal can be synthesized.

[0076] CY 1 2 = CY 2 RfX (1)

[0077] [Y 1 and Y 2 each independently is a fluorine atom, a hydrogen atom, or a methyl group, Rf is a straight-chain or branched-chain fluorine-containing alkylene group in which part or all of hydrogen atoms are replaced with fluorine atoms, or a group in which part of the fluorine-containing alkylene group contains an ether bond, and X is an iodine atom or a bromine atom.

[0078] As a specific example of the compound represented by the above formula (1), a compound described in International Publication No. 2009 / 119409 can be exemplified.

[0079] I n Br m R (2)

[0080] [R is a fluorinated hydrocarbon group having 1 to 12 carbon atoms, and n and m each independently are an integer of 0 to 2, and n + m is 1 or 2.]

[0081] As a specific example of the compound represented by the above formula (2), a compound described in Japanese Patent Laid-Open No. 2002-97329 or Japanese Patent Laid-Open No. 2008-56739 can be exemplified.

[0082] <cross-linking agent>

[0083] As the cross-linking agent, there is no particular limitation, and a cross-linking agent known in the art can be used according to the kind of the elastomer (A) to be used.

[0084] The cross-linking agent can be used singly or two or more kinds can be used.

[0085] As the cross-linking agent, for example, in the case where FKM is used, a peroxide-based cross-linking agent, a polyamine-based cross-linking agent, a polyol-based cross-linking agent, a triazine-based cross-linking agent, and the like can be exemplified.

[0086] Among them, from the viewpoint that it is not necessary to incorporate an acid-adsorbing agent such as magnesium oxide, calcium hydroxide, or the like, which becomes a particle generation source in a plasma atmosphere or the like, in the present composition, and that the resulting sealing material does not have a risk of particle generation during use, and the like, a peroxide-based cross-linking agent is preferred.

[0087] As the peroxide-based crosslinking agent, for example, 2,5-dimethyl-2,5-di(tert- butylperoxy)hexane, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, di-tert- butyl peroxide, tert-butylcumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-(tert- butylperoxy)-3-hexyne, 2,5-dimethyl-2,5-di(benzoyl peroxide)hexane, α,α'-bis(tert- butylperoxy-m-isopropyl)benzene, tert-butylperoxy isopropyl carbonate, di(4-tert- butylcyclohexyl)peroxydicarbonate, p-chlorobenzoyl peroxide, tert-butylperoxy-2- ethylhexanoate, tert-butylperoxybenzoate, 1,1-bis(tert-butylperoxy)-3,5,5- trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, α,α-bis(tert- butylperoxy)-p-diisopropylbenzene, tert-butylperoxybenzene, tert-butylperoxy maleate can be mentioned.

[0088] Among them, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, benzoyl peroxide, α,α'-bis(tert-butylperoxy-m- isopropyl)benzene are preferred, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is more preferred.

[0089] The content of the crosslinking agent in the present composition is preferably 0.2 to 4 parts by mass, and more preferably 0.2 to 2.5 parts by mass, relative to 100 parts by mass of the elastomer (A), from the viewpoint that the crosslinking reaction sufficiently proceeds and that a sealing material, etc. exhibiting excellent hardness, tensile strength, elongation at break, and 100% Mo, etc. in good balance can be easily obtained.

[0090] <crosslinking aid>

[0091] As the crosslinking aid, there is no particular limitation, and a crosslinking aid known in the art can be used according to the type of the crosslinking agent.

[0092] The crosslinking aid can be used singly or in combination of two or more.

[0093] For example, as examples of the crosslinking aid used in the case of using a peroxide-based crosslinking agent, isocyanuric acid triallyl ester, cyanuric acid triallyl ester, isocyanuric acid trimethallyl ester, formaldehyde triallyl ester, trimellitic acid triallyl ester, N,N'-m-phenylene bismaleimide, terephthalic acid dipropargyl ester, phthalic acid diallyl ester, tetraallyl terephthalamide, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and other multi-functional (meth)acrylates, and the like, which are compounds capable of crosslinking by radicals (multi-functional monomers), higher carboxylic acid metal salts, polyhydric alcohol (meth)acrylates, and (meth)acrylic acid metal salts can be mentioned.

[0094] Among them, triallyl isocyanurate is excellent in reactivity and heat resistance, and a sealing material of high modulus is easily obtained with high hardness, and thus is preferred.

[0095] From the viewpoint that a sealing material exhibiting excellent hardness, tensile strength, elongation at break, and 100% Mo with good balance is easily obtained by sufficient progress of crosslinking reaction, the content of the crosslinking aid in the present composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 4 parts by mass or more, relative to 100 parts by mass of the elastomer (A), and is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and further preferably 6 parts by mass or less.

[0096] In particular, in order to suppress cracking of a sealing material that can occur in a plasma atmosphere or the like, a sealing material crosslinked by radiation (radiation-treated product) is preferred. In this case, from the viewpoint that a sealing material of higher modulus is easily obtained with higher hardness even without using a filler material described later, the content of the crosslinking aid in the present composition is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, and is preferably 7 parts by mass or less, and more preferably 6 parts by mass or less, relative to 100 parts by mass of the elastomer (A).

[0097] From the viewpoint that a sealing material exhibiting desired properties is easily obtained by making the crosslinking agent react just right, and in particular, a sealing material of higher modulus is easily obtained with higher hardness even without using a filler material described later, the mass ratio of the content of the crosslinking aid to the content of the crosslinking agent (content of crosslinking aid / content of crosslinking agent) in the present composition is preferably 4 or more, more preferably 6 or more, and is preferably 30 or less, and further preferably 20 or less.

[0098] <Other Components>

[0099] The present composition can contain, in addition to the above components, other components conventionally known to be blended in a sealing material, as needed, without impairing the effects of the present application. As the other components, for example, the following can be exemplified: a compound containing an ethylenic unsaturated bond; a reactive organosilicon compound having two or more hydrosilyl groups in the molecule; a catalyst; an acid acceptor such as magnesium oxide and calcium hydroxide; an anthraquinone pigment, a perylene pigment, and a dioxazine pigment or the like organic pigment; a plasticizer; a processing aid; a vulcanization accelerator; an anti-aging agent; an antioxidant; an inorganic filler; and an organic filler.

[0100] The other components can be used individually only one kind, or two or more kinds can be used.

[0101] [Compound Containing an Ethylenic Unsaturated Bond]

[0102] ​From the viewpoint of being able to easily obtain a non-adhesive sealing material or the like having excellent plasma resistance, the present composition preferably contains a compound containing an ethylenic unsaturated bond (hereinafter also referred to as "compound (B)").

[0103] As the compound (B), at least one compound selected from a compound (B1) having a perfluoro skeleton with an ethylenic unsaturated bond and a compound (B2) having a siloxane skeleton with an ethylenic unsaturated bond can be exemplified. Among them, from the viewpoint of being able to easily obtain a sealing material or the like having more excellent plasma resistance, the compound (B) preferably contains the compound (B1).

[0104] As the ethylenic unsaturated bond, a carbon number 2 to 8 alkenyl group such as a vinyl group, a methylvinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, a vinylphenyl group, a (meth)acryl group, an allyloxy group, a styryl group, and an propargyl group can be exemplified. Among them, an alkenyl group is preferred, a carbon number 2 to 4 alkenyl group is more preferred, and a vinyl group is particularly preferred.

[0105] The compound (B) can have two or more ethylenic unsaturated bonds.

[0106] The compound (B) can be synthesized by a method known in the art, or can be a commercially available product. As the commercially available product, "SIFEL" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be exemplified.

[0107] As the commercially available product containing the compound (B), either a one-component type commercially available product or a two-component type commercially available product can be used. Further, as the commercially available product containing the compound (B), either a liquid type, a paste type, an oil type, a mirable type, or the like can be used.

[0108] In the case where a commercially available product is used as the compound (B), the commercially available product sometimes contains a reactive organosilicon compound having two or more hydrosilyl groups in a molecule (for example, the organosilicon compounds described in Japanese Patent Laid-Open No. 2003-183402, Japanese Patent Laid-Open No. H11-116684, and the like), a catalyst (for example, the catalysts described in Japanese Patent Laid-Open No. 2003-183402, Japanese Patent Laid-Open No. H11-116684, and the like), a filler (for example, silica), and the like as additives. As the compound (B), a compound containing these additives can also be used.

[0109] In the case where the present composition contains the compound (B), the content of the compound (B) in the present composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the elastomer (A), and is preferably 50 parts by mass or less, more preferably 25 parts by mass or less, further preferably 10 parts by mass or less, from the viewpoint that a uniform elastomer composition can be obtained in a shorter time, a sealing material having more excellent plasma resistance can be easily obtained, and the like.

[0110] In the case where the present composition contains the compound (B) and the crosslinking agent described below, the mass ratio of the content of the compound (B) to the content of the crosslinking agent (content of the compound (B) / content of the crosslinking agent) in the present composition is preferably 1 or more, more preferably 2 or more, and is preferably 20 or less, more preferably 10 or less, from the viewpoint that a sealing material having excellent plasma resistance can be easily obtained, and the like.

[0111] [Compound (B1)]

[0112] The compound (B1) is a compound other than the elastomer (A).

[0113] As the compound (B1), a compound having a perfluoropolyether structure having an ethylenic unsaturated bond, a compound having a perfluoroalkylene structure having an ethylenic unsaturated bond can be exemplified. Among them, a compound having a perfluoropolyether structure having an ethylenic unsaturated bond (hereinafter also referred to as "compound (B1-1)") is preferred.

[0114] In the case where the present composition contains the compound (B1), the compound (B1) contained in the present composition can be one or two or more.

[0115] • Compound (B1-1)

[0116] As the compound (B1-1), a perfluoropolyether having two or more ethylenic unsaturated bonds in one molecule is preferred.

[0117] As a preferred example of the compound (B1-1), a compound described in Japanese Patent Application Publication No. 2003-183402, Japanese Patent Application Publication No. H11-116684, Japanese Patent Application Publication No. H11-116685, and Japanese Patent Application Publication No. 2015-67737 can be exemplified.

[0118] As the compound (B1-1), a compound represented by the following formula (1), for example, can be exemplified.

[0119] Z 1 -(X) p -(Rf-Q) a -Rf-(X) p -Z 2 ...(1)

[0120] X is independently -CH2-, -CH2O-, -CH2OCH2-, -Si(R 2 )2-Ph-(Ph: phenylene group), -Y-NR 1 SO2- or -Y-NR 1 -CO- (wherein Y is -CH2- or -Si(R 2 )2-Ph-, the * moiety being bonded to Z 1 or Z 2 ).

[0121] Rf is a divalent perfluoropolyether group (divalent perfluorooxyalkylene group).

[0122] p is independently 0 or 1; a is an integer of 0 or more, preferably an integer of 0 to 10, more preferably an integer of 0 to 6.

[0123] Q is a group represented by the following formula (2), (3) or (4).

[0124] R 2 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, such as alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, decyl and the like, cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl and the like, alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl and the like, aryl groups such as phenyl, tolyl, xylyl, naphthyl and the like, aralkyl groups such as benzyl, phenethyl, phenylpropyl and the like, and groups in which part or all of the hydrogen atoms of these groups are substituted with halogen atoms or the like (e.g., chloromethyl, chloropropyl, bromoethyl, 3,3,3-trifluoropropyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl and the like fluorine-substituted alkyl groups).

[0125] R 1 is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, which is the same as the group described above as R 2 , such as a hydrogen atom or a group which is the same as R 2 , such as alkyl groups such as methyl, ethyl, propyl, isopropyl and the like, cyclohexyl and the like cycloalkyl groups, vinyl, allyl and the like alkenyl groups, phenyl and the like aryl groups, and groups in which part or all of the hydrogen atoms of these groups are substituted with halogen atoms or the like (e.g., chloromethyl, chloropropyl, 3,3,3-trifluoropropyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl and the like fluorine-substituted alkyl groups).

[0126] Z 1 and Z 2 are each independently a group containing an ethylenic unsaturated bond, and can be -Si(R')2.

[0127] As the group having an ethylenically unsaturated bond, a monovalent alkenyl group is preferred, a monovalent alkenyl group having 2 to 4 carbon atoms is more preferred, and a monovalent vinyl group is particularly preferred.

[0128] R' is independently a substituted or unsubstituted monovalent hydrocarbon group, and specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, hexyl, and the like; aryl groups such as phenyl, tolyl, xylyl, and the like; and haloalkyl groups such as 3-chloropropyl, 3,3,3-trifluoropropyl, and the like. Among these, alkyl groups having 1 to 5 carbon atoms are preferred.

[0129] [Chemical Formula 1]

[0130]

[0131] -(X) p -CH2CH2R 4 CH2CH2-(X) p -.-(3)

[0132]

[0133] In formulae (2) to (4), X, p, R 1 X, p, R 1 are the same as in formula (1) above. R 3 and R 4 are each independently a substituted or unsubstituted divalent hydrocarbon group which can optionally have one or more atoms selected from the group consisting of oxygen atoms, nitrogen atoms, silicon atoms, and sulfur atoms interposed in the middle of the bond, R 3 in formula (2) and R 4 in formula (3) can each independently be a group represented by the following formula (5) or (6).

[0134] [Chemical Formula 2]

[0135]

[0136] In formulae (5) and (6), R 5 is a substituted or unsubstituted monovalent hydrocarbon group, and R 6 is a group having one or more atoms selected from the group consisting of carbon atoms, oxygen atoms, nitrogen atoms, silicon atoms, and sulfur atoms.

[0137] R 3 and R 4Any substituted or unsubstituted divalent hydrocarbon group is acceptable, with no particular limitation. Preferred divalent hydrocarbon groups have 1 to 20 carbon atoms, especially 2 to 12. Examples include alkylene groups such as methylene, ethylene, propylene, methyl ethylene, butylene, and hexamethylene; cyclohexylene groups such as cyclohexylene; and aryl groups such as phenylene, tolylene, xylene, naphthylene, and biphenylene. Groups in which some hydrogen atoms of these groups are replaced by halogen atoms, as well as combinations of these substituted or unsubstituted alkylene and aryl groups.

[0138] Preferred - (X) p -(Rf-Q) a -Rf-(X) p -for-(OR) 7 ) n -[R 7 Represents a perfluoroalkyl dimethyl group, where n represents an integer greater than or equal to 2. Multiple existing R groups... 7 They can be the same or different.

[0139] As a result of R 7 The perfluoroalkyl dimethyl group represented can be exemplified by C m F 2m The group represented by (m is an integer of 2 or more) can be linear or branched. The number of carbons (i.e., m) of the perfluoroalkyl diester is, for example, 1 to 10, preferably 2 to 6, more preferably 2 to 4, and particularly preferably 2 to 3.

[0140] n can be 2 or more, for example, 10 or more, preferably 40 or more, and more preferably 70 or more. Alternatively, n can be 300 or less, preferably 200 or less, and more preferably 150 or less.

[0141] -(OR 7 ) n - It can be the same group as Rf below.

[0142] The compound represented by formula (1) above is preferably the compound represented by formula (1-1) below.

[0143] CH2=CH-(X) p -(Rf-Q) a -Rf-(X) p -CH=CH2···(1-1)

[0144] [The definitions of the symbols in equation (1-1) are the same as those in equation (1).]

[0145] Furthermore, the compound represented by the above formula (1-1) is preferably a compound in which a is 0, in which case it is represented by the following formula (1-1-1).

[0146] CH2=CH-(X) p-Rf-(X) p -CH=CH2···(1-1-1)

[0147] [The definitions of the symbols in formula (1-1-1) are the same as those in formula (1).]

[0148] Specific examples of the Rf can be exemplified by the following groups.

[0149] -[CF(Z)OCF2] p -(CF2) r -[CF2OCF(Z)] q -

[0150] (Z is a fluorine atom or -CF3, p, q, r are integers satisfying p > 1, q > 1, 2 < p + q < 200, preferably 2 < p + q < 110, 0 < r < 6),

[0151] -CF2CF2OCF2-(CF(CF3)OCF2) s -(CF2) r -(CF2OCF(CF3)) t -CF2OCF2CF2-

[0152] (r, s, t are integers satisfying 0 < r < 6, s > 0, t > 0, 0 < s + t < 200, preferably 2 < s + t < 110),

[0153] -CF(Z)-(OCF(Z)CF2) u -(OCF2) v -OCF(Z)-

[0154] (Z is a fluorine atom or -CF3, u and v are integers satisfying 1 < u < 100 and 1 < v < 50),

[0155] -CF2CF2-[OCF2CF2CF2] w -OCF2CF2-

[0156] (w is an integer satisfying 1 < w < 100).

[0157] [Compound (B2)]

[0158] The compound (B2) is preferably a polysiloxane having two or more ethylenic unsaturated bonds in one molecule, preferably an organopolysiloxane having two or more ethylenic unsaturated bonds in one molecule and an organic group bonded to a silicon atom. The bonding position of the ethylenic unsaturated bond is not particularly limited.

[0159] In the case where the present composition contains the compound (B2), the compound (B2) contained in the present composition can be one or two or more.

[0160] As the organic group bonded to a silicon atom, there can be mentioned, for example, the aforementioned ethylenically unsaturated group, straight-chain alkyl group, branched-chain alkyl group, cyclic alkyl group, aryl group, aralkyl group, and halogenated alkyl group.

[0161] As the straight-chain alkyl group, there can be mentioned, for example, a group having a carbon number of 1 to 10, preferably 1 to 6, such as methyl group, ethyl group, propyl group, hexyl group, octyl group, decyl group, and the like.

[0162] As the branched-chain alkyl group, there can be mentioned, for example, a group having a carbon number of 1 to 20, preferably 1 to 6, such as isopropyl group, isobutyl group, tert-butyl group, 2-ethylhexyl group, and the like.

[0163] As the cyclic alkyl group, there can be mentioned, for example, a group having a carbon number of 3 to 20, such as cyclopentyl group, cyclohexyl group, and the like.

[0164] As the aryl group, there can be mentioned, for example, a group having a carbon number of 6 to 20, such as phenyl group, tolyl group, and the like.

[0165] As the aralkyl group, there can be mentioned, for example, a group having a carbon number of 7 to 20, such as benzyl group, 2-phenylethyl group, 2-methyl-2-phenylethyl group, and the like.

[0166] As the halogenated alkyl group, there can be mentioned, for example, a group having a carbon number of 1 to 20, preferably 1 to 6, such as 3,3,3-trifluoropropyl group, 2-(nonafluorobutyl)ethyl group, 2-(heptadecafluorooctyl)ethyl group, and the like.

[0167] As the aforementioned organic group bonded to a silicon atom, a straight-chain alkyl group, alkenyl group, aryl group are preferred, a straight-chain alkyl group, alkenyl group, aryl group having a carbon number of 1 to 6 are more preferred, and a methyl group, vinyl group, phenyl group are particularly preferred.

[0168] The molecular structure of the compound (B2) is not particularly limited. There can be mentioned, for example, straight-chain, branched-chain, straight-chain having a partial branched-chain, dendritic (branching), and straight-chain, straight-chain having a partial branched-chain are preferred. The compound (B2) can be a homopolymer having these molecular structures, a copolymer having these molecular structures, a mixture of two or more of these polymers.

[0169] As the compound (B2), for example, dimethylpolysiloxane in which both terminals of the molecular chain are capped with dimethylvinylsiloxy group, dimethylpolysiloxane in which both terminals of the molecular chain are capped with methylphenylvinylsiloxy group, dimethylsiloxane-methylphenylsiloxane copolymer in which both terminals of the molecular chain are capped with dimethylvinylsiloxy group, dimethylsiloxane-methylvinylsiloxane copolymer in which both terminals of the molecular chain are capped with dimethylvinylsiloxy group, dimethylsiloxane-methylvinylsiloxane copolymer in which both terminals of the molecular chain are capped with silanol group, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer in which both terminals of the molecular chain are capped with silanol group, dimethylsiloxane-methylvinylsiloxane copolymer in which both terminals of the molecular chain are capped with trimethylsiloxy group, methyl(3,3,3-trifluoropropyl)polysiloxane in which both terminals of the molecular chain are capped with dimethylvinylsiloxy group, a siloxane copolymer composed of siloxane units represented by the formula: (CH3)3SiO 1 / 2 1 / 2 3 / 2 2 / 2

[0170] [Chem. 3]

[0171]

[0172] [In the formula (7), each R 1 is independently a non-substituted or substituted monovalent hydrocarbon group, each R 2 is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, b is an integer of 2 to 100, and a is an integer of 1 to 3. In the formula (7), R 1 and at least two of R 2 contain the ethylenic unsaturated bond.]

[0173] In the formula (7), R 1 is independently a non-substituted or substituted monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having a carbon number of 1 to 10, and as examples thereof, the same groups as those exemplified above as the organic group bonded to a silicon atom can be mentioned. Among them, a monovalent hydrocarbon group having a carbon number of 1 to 6 is preferred, and an alkenyl group, an aryl group, an alkyl group having a carbon number of 1 to 3 is more preferred.

[0174] As the alkyl group and the alkenyl group of R 2 in the formula (7), for example, the same straight-chain alkyl group, branched-chain alkyl group, cyclic alkyl group, alkenyl group as those exemplified above as the organic group bonded to a silicon atom can be mentioned.

[0175] As the alkyl group and the alkenyl group of R 2 ​​​​As the acyl group of R

[0176] As the R 2 group of R

[0177] b in the formula (7) is preferably an integer of 10 to 50, and a is preferably 3.

[0178] [Reactive organosilicon compound]

[0179] The reactive organosilicon compound is a compound other than the compound (B2), and preferably exemplified are the same compounds as those described in Japanese Patent Laid-Open No. 2003-183402, Japanese Patent Laid-Open No. 11-116684, and the like, which have two or more hydrosilyl groups in the molecule.

[0180] [Catalyst]

[0181] As the catalyst, preferably exemplified are the same catalysts as those described in Japanese Patent Laid-Open No. 2003-183402, Japanese Patent Laid-Open No. 11-116684, and the like.

[0182] [Organic pigment]

[0183] As the organic pigment, preferably exemplified are the same organic pigments as those described in International Publication No. 2016 / 043100, Japanese Patent No. 4720501, International Publication No. 2004 / 094527, and the like.

[0184] [Filler]

[0185] The inorganic filler and the organic filler (hereinafter simply referred to as "filler") are particulate (powdered) components other than the crosslinking agent, the crosslinking aid, and the compound (B).

[0186] As the inorganic filler, exemplified are, for example, carbon black, silica, barium sulfate, titanium oxide, and aluminum oxide.

[0187] As the organic filler, exemplified are, for example, fluororesins such as PTFE, PFA, FEP, ETFE, and PVDF, polyethylene resin, polyimide resin, silicone resin, and melamine resin.

[0188] In the case where the present sealing material is used for manufacturing a sealing material in which particle generation in a plasma atmosphere or the like is a problem, the content of the filler is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and most preferably 0 part by mass, with respect to 100 parts by mass of the elastomer (A).

[0189] <Manufacturing method of the present composition>

[0190] The present composition can be manufactured by mixing (kneading) the elastomer (A), the crosslinking agent, the crosslinking aid, and the other ingredients as needed. It is preferable to manufacture by mixing (kneading) the elastomer (A), the crosslinking agent, the crosslinking aid, the compound (B), and the other ingredients as needed.

[0191] The order of mixing of the elastomer (A), the crosslinking agent, the crosslinking aid, and the other ingredients is not particularly limited, and they can be mixed (kneaded) sequentially in any order, or they can be mixed (kneaded) all at once. It is preferable to mix (knead) sequentially so that each ingredient is uniform.

[0192] A mixing (kneading) machine known in the art can be used for the mixing (kneading), and examples include an open roll press, a Banbury mixer, a two-roll press, and a kneader.

[0193] In addition, the mixing (kneading) can be performed with heating or cooling as needed, depending on the mixing (kneading) machine.

[0194] <Manufacturing method of the present sealing material>

[0195] The present sealing material can be manufactured by a method including a step of irradiating a radiation to the present composition or a crosslinked product thereof (radiation irradiation step).

[0196] By including the radiation irradiation step as described above, a sealing material having more excellent plasma resistance (radical resistance), crack resistance, compression set, non-adhesion, and the like, and exhibiting excellent hardness, tensile strength, elongation at break, and 100% Mo in a good balance can be easily obtained, and the occurrence of cracks in the sealing material in a plasma atmosphere or the like can be suppressed

[0197] When the present sealing material is formed from the present composition, it is preferable to perform a tabletting step from the viewpoint of improving the efficiency of the forming operation and reducing the defective rate or the like. The tabletting step is usually performed using a roll or the like, and is also a step of previously forming the present composition into a tablet shape.

[0198] The tablet obtained by the tabletting step is preferably pre-formed into a desired sealing material shape before the crosslinking step and the radiation irradiation step.

[0199] In the pre-forming, the tablet obtained in the tabletting step can be directly formed into a desired sealing material shape, or the tablet obtained in the tabletting step can be formed into a string shape (a tape shape, a noodle shape, or the like) by cutting or extrusion forming or the like, and the obtained string-shaped product can be formed into a desired sealing material shape.

[0200] When the present sealing material is manufactured, a cross-linking step is preferably included before the radiation irradiation step, and more preferably the cross-linking step includes a primary cross-linking step and a secondary cross-linking step.

[0201] The cross-linking step is preferably performed using the desired sealing material shape obtained by the preforming.

[0202] The primary cross-linking step is preferably a step of heating and pressurizing the desired sealing material shape obtained by the preforming. Specifically, a step of, for example, placing the preformed material in a mold, and performing cross-linking at a temperature of, for example, 150 to 200°C for, for example, 5 to 20 minutes under pressurization of, for example, 2 to 15 MPa using a hot press or the like can be exemplified.

[0203] The secondary cross-linking step is preferably a step of heating the shaped body obtained in the primary cross-linking step. Specifically, a step of heating at a temperature of, for example, 150 to 300°C for, for example, 1 to 24 hours, more preferably about 3 to 24 hours under normal pressure to reduced pressure using various ovens, preferably a vacuum oven can be exemplified.

[0204] By the secondary cross-linking step, cross-linking is promoted, and even if unreacted components remain after the primary cross-linking step, the unreacted components can be decomposed and volatilized, and a sealing material that generates less released gas can be obtained.

[0205] The radiation irradiated in the radiation irradiation step is not particularly limited as long as it can cross-link the elastomer (A), and a step of, for example, X-rays, γ-rays, electron beams, proton beams, neutron beams, heavy particle beams, α-rays, β-rays can be exemplified, of which γ-rays and electron beams are preferred.

[0206] The radiation irradiated can be one kind alone, or two or more kinds can be used.

[0207] When the radiation is irradiated, it is preferable to irradiate the radiation under conditions in which the absorbed dose is preferably 1 to 120 kGy, more preferably 20 to 100 kGy. By irradiating the radiation in this amount, unreacted components that become particles or released gas can be reduced, and a sealing material having excellent plasma resistance, crack resistance, and the like can be easily obtained without the molecular weight of the elastomer (A) becoming too low.

[0208] The radiation irradiation step can be performed in two or more stages by changing the conditions.

[0209] When the radiation is irradiated, it can be irradiated in air, but if oxygen is present during the radiation irradiation, the cross-linking reaction can be inhibited, the mechanical strength of the sealing material can decrease, and the surface of the sealing material can become tacky. Therefore, the radiation irradiation step is preferably performed in an inert gas atmosphere such as nitrogen or argon.

[0210] Embodiments

[0211] Next, the present application is described in more detail with reference to embodiments, but the present application is not limited thereto.

[0212] <elastomer>

[0213] The elastomers used in the following examples and comparative examples are as follows.

[0214] • Elastomer (A1-1): Tecnoflon P757 (manufactured by Solvay, fluorine content: 67 mass%)

[0215] • Elastomer (A1-2): Tecnoflon P457 (manufactured by Solvay, fluorine content: 67 mass%)

[0216] • Elastomer (A2-1): DAI-EL G912 (manufactured by Daikin Industries, Ltd., fluorine content: 71 mass%)

[0217] • Elastomer (A2-2): Tecnoflon P959 (manufactured by Solvay, fluorine content: 70 mass%)

[0218] • Elastomer (A2-3): Tecnoflon P459 (manufactured by Solvay, fluorine content: 70 mass%)

[0219] • Elastomer (A2-4): Tecnoflon PL855 (manufactured by Solvay, fluorine content: 64 mass%)

[0220] • Elastomer (A2-5): DAI-EL T302 (manufactured by Daikin Industries, Ltd., fluorine content: 65 mass%)

[0221] [Example 1]

[0222] The elastomer (A1-1) 20 parts by mass, the elastomer (A2-2) 80 parts by mass, SIFEL 8070A (manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part by mass, SIFEL 8070B (manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part by mass, TAIC (manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate) 6.0 parts by mass, and Perhexa 25B (manufactured by NOF Corporation) 0.5 part by mass were sequentially charged into a kneader and mixed until the current value stabilized, thereby obtaining a blocky elastomer composition.

[0223] At least one of SIFEL 8070A and SIFEL 8070B contains a compound having a perfluorinated skeleton having an ethylenic unsaturated bond.

[0224] The kneading time was defined as the total time from the initial ingredients were added to the kneader to the current value became stable after the final ingredient was added. The results are shown in Table 1.

[0225] In general, in the case of using a kneader for mixing, if each added ingredient is uniformly mixed, the current value reaches a stable value, and therefore, the current value reaching a stable value is often used as a criterion for completion of mixing to determine that a uniform composition has been obtained.

[0226] The obtained block elastomer composition was subjected to a sheeting process (sheeting process) using a roll (roll gap: 8 mm, temperature: 50°C).

[0227] At this time, if the block elastomer composition can be formed into a sheet, the sheeting property is "OK", and if the elastomer composition is not bitten between the rolls or has poor adhesion to the rolls and good sheeting is not obtained, the sheeting property is "NG", and the sheeting property was evaluated in this way. The results are shown in Table 1.

[0228] The sheet obtained in the above sheeting process was subjected to press molding (primary crosslinking) at 170°C for 10 minutes under a pressure of 5 MPa using a compression vacuum press, and then the sheet after press molding was placed in a vacuum oven (vacuum degree: 50 Pa) and heated at 200°C for 16 hours under reduced pressure (secondary crosslinking). Then, the sheet after secondary crosslinking was irradiated with a radiation ray under conditions such that the absorbed dose reached 80 kGy, thereby obtaining a molded body.

[0229] The obtained molded body was measured for the following general physical properties. The results are shown in Table 1.

[0230] <General Physical Properties>

[0231] As the general physical properties, the Shore A hardness was measured in accordance with JIS K 6253:2012, and the tensile strength, elongation at break, and tensile stress at 100% elongation (100% Mo) were measured in accordance with JIS K6251:2017.

[0232] [Examples 2 to 6 and Comparative Examples 1 and 2]

[0233] Various evaluations were performed in the same manner as in Example 1 except that the elastomers shown in Table 1 were used in the amounts shown in Table 1. The results are shown in Table 1.

[0234] [Table 1]

[0235]

[0236] In Examples 1 to 6, the time required to manufacture a uniform elastomer composition was short, and the sheeting property (sheet forming property) of the elastomer composition obtained in Examples 1 to 6 was excellent.

[0237] In Comparative Examples 1 and 2, it took a long time to prepare the uniform elastomer composition, and the elastomer composition obtained in Comparative Examples 1 and 2 had poor tabletability, specifically, the elastomer composition was not bitten between the rollers or was not smoothly wound onto the rollers, so that a good sheet could not be formed.

[0238] [Example 7]

[0239] Crosslinkable fluorine-containing elastomer (A1-1) 30 parts by mass, crosslinkable fluorine-containing elastomer (A2-1) 70 parts by mass, SIFEL 3590-N (manufactured by SHIN-ETU CHEMICAL CO., LTD., compound containing a perfluorinated skeleton having an olefinic unsaturated bond, single liquid type) 2 parts by mass, TAIC 6 parts by mass, and Perhexa 25B 0.5 parts by mass were sequentially charged into a kneader and kneaded until the current value was stabilized, to obtain a blocky elastomer composition.

[0240] Using the obtained blocky elastomer composition, a shaped body was obtained in the same manner as in Example 1.

[0241] The above general physical properties and the following plasma resistance of the obtained shaped body were measured. The results are shown in Table 2.

[0242] [Example 8]

[0243] A blocky elastomer composition was obtained in the same manner as in Example 7, except that the amount of SIFEL 3590-N was 10 parts by mass and the amount of Perhexa 25B was 1 part by mass.

[0244] Using the obtained blocky elastomer composition, a shaped body was obtained in the same manner as in Example 1.

[0245] The above general physical properties and the following plasma resistance of the obtained shaped body were measured. The results are shown in Table 2.

[0246] [Example 9]

[0247] A blocky elastomer composition was obtained in the same manner as in Example 7, except that the amount of SIFEL 3590-N was 20 parts by mass and the amount of Perhexa 25B was 1 part by mass.

[0248] Using the obtained blocky elastomer composition, a shaped body was obtained in the same manner as in Example 1.

[0249] The above general physical properties and the following plasma resistance of the obtained shaped body were measured. The results are shown in Table 2.

[0250] [Example 10]

[0251] The same operation as in Example 7 was conducted except that 2 parts by mass of KE-1830 (manufactured by Shin-Etsu Chemical Co., Ltd., liquid type of single liquid containing a siloxane skeleton having an ethylenic unsaturated bond) was used instead of 2 parts by mass of SIFEL 3590-N to obtain an elastomer composition in a block shape.

[0252] The same operation as in Example 1 was conducted using the obtained elastomer composition in a block shape to obtain a molded body.

[0253] The above general physical properties and the following plasma resistance of the obtained molded body were measured. The results are shown in Table 2.

[0254] <Plasma resistance>

[0255] The plasma resistance (mass reduction rate) of the obtained molded body was measured. Specifically, the measurement was conducted as follows.

[0256] A flat plate plasma treatment device having an electrode diameter of φ 300 mm and an electrode distance of 50 mm was used, and the obtained molded body was irradiated with plasma under conditions of RF 500 W, CF4 gas flow rate 50 seem, O2 gas flow rate 150 seem, and vacuum degree 1 torr for 3 hours.

[0257] The obtained molded body was placed at a position 6 cm from the plasma electrode. Then, the mass of the molded body before and after the test was measured, and the mass reduction rate (%) was calculated from the following equation, whereby the plasma resistance was evaluated. It can be said that the smaller the mass reduction rate, the better the plasma resistance.

[0258] Mass reduction rate (%) = [(mass of molded body before test - mass of molded body after test) / mass of molded body before test] x 100

[0259] [Table 2]

[0260]

[0261] [Examples 11 to 12 and Comparative Examples 3 to 7]

[0262] The same operation as in Example 1 was conducted except that the elastomers shown in Table 3 were used in the amounts shown in Table 3 to obtain an elastomer composition in a block shape.

[0263] The obtained elastomer composition in a block shape was filled into a mold, and press molding (primary crosslinking) was conducted at a pressure of 5 MPa at 170°C for 10 minutes using a compression vacuum press, and then the sheet after press molding was placed in a vacuum oven (vacuum degree: 50 Pa) and heated at 200°C for 16 hours under reduced pressure (secondary crosslinking). Then, the sheet after secondary crosslinking was irradiated with a radiation under conditions such that the absorbed dose reached 80 kGy, whereby a molded body was obtained.

[0264] The obtained shaped bodies were measured for the above-mentioned general properties. The results are shown in Table 3.

[0265] [Table 3]

[0266]

[0267] [Examples 13 to 15]

[0268] A radiation-crosslinked body was prepared in the same manner as in Example 11, except that the elastomers shown in Table 4 were used in the amounts shown in Table 4.

[0269] Among them, SIFEL 8070A and SIFEL 8070B were not used in Example 15.

[0270] [Comparative Examples 8 to 9]

[0271] A secondary-crosslinked body was prepared in the same manner as in Example 11, except that the elastomers shown in Table 4 were used in the amounts shown in Table 4, and no radiation was applied.

[0272] [Compression set]

[0273] From the radiation-crosslinked bodies obtained in Examples 13 to 15 or the secondary-crosslinked bodies obtained in Comparative Examples 8 to 9, a test sample (AS214 O-ring) was prepared in accordance with JIS K 6262:2013. After the prepared O-ring was compressed by 25% in the thickness direction at 200°C for 70 hours, the thickness of the crosslinked body 30 minutes after removal from the compression device was measured, and the compression set was calculated. The results are shown in Table 4.

[0274] [Table 4]

[0275]

Claims

1. A sealing material which is a radiation crosslinked body of an elastomer composition comprising a crosslinkable fluorine-containing elastomer (A) other than a perfluoroelastomer, a crosslinking agent, and a crosslinking co-agent, wherein, The cross-linkable fluorine-containing elastomer (A) includes a cross-linkable fluorine-containing elastomer (Al) other than a perfluoroelastomer having a fluorine content in the range of 66 to 68 mass% and a cross-linkable fluorine-containing elastomer (A2) other than a perfluoroelastomer having a fluorine content in the range of 69 to 73 mass%, and the content of the cross-linkable fluorine-containing elastomer (Al) is 5 mass% or more and 35 mass% or less relative to the total content of the cross-linkable fluorine-containing elastomer (Al) and the cross-linkable fluorine-containing elastomer (A2).

2. The sealing material of claim 1, wherein, The fluorine-containing elastomer (A) is a peroxide-cross-linkable fluorine-containing elastomer.

3. The sealing material of claim 1, wherein, The elastomer composition includes at least one olefinically unsaturated bond-containing compound selected from a compound having a perfluoro skeleton with an olefinically unsaturated bond and a compound having a siloxane skeleton with an olefinically unsaturated bond.

4. The elastomer composition according to any one of claims 1 to 3, wherein, The content of the filler is 5 mass% or less relative to 100 mass parts of the fluorine-containing elastomer (A).

5. A method for producing a sealing material, wherein, A process of irradiating a cross-linkable fluorine-containing elastomer (A) other than a perfluoroelastomer, a cross-linking agent, and a cross-linking co-agent, and the cross-linkable fluorine-containing elastomer (A) includes a cross-linkable fluorine-containing elastomer (Al) other than a perfluoroelastomer having a fluorine content in the range of 66 to 68 mass% and a cross-linkable fluorine-containing elastomer (A2) other than a perfluoroelastomer having a fluorine content in the range of 69 to 73 mass%, and the content of the cross-linkable fluorine-containing elastomer (Al) is 5 mass% or more and 35 mass% or less relative to the total content of the cross-linkable fluorine-containing elastomer (Al) and the cross-linkable fluorine-containing elastomer (A2).

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