Elastomer composition, sealing material and method for producing sealing material

Abstract

One embodiment of the present invention relates to an elastomer composition, a sealing material, or a method for producing the sealing material. The elastomer composition comprises: a crosslinkable fluoroelastomer (A) [the elastomer (A) is a compound having no hydrosilyl group]; and a composition (B) which comprises at least one compound containing an ethylenically unsaturated bond that is selected from among perfluorinated-skeleton compounds each having an ethylenically unsaturated bond [said compounds are not the elastomer (A)] and siloxane-skeleton compounds each having an ethylenically unsaturated bond and which has a minimum torque (ML), as measured at 60°C with Curelastometer, of 0.5 kgf·cm or greater.

Description

[Technical field]

[0001] An embodiment of the present invention relates to an elastomer composition, a sealing material, or a method for producing a sealing material. [Background technology]

[0002] 2. Description of the Related Art Conventionally, sealing materials have been used widely for various applications. Among these applications, an example of an application of a sealing material that places the greatest load on the sealing material is a sealing material used in semiconductor manufacturing equipment, etc.

[0003] As such sealing materials, cross-linkable fluoroelastomers such as fluoroelastomers (FKM) and perfluoroelastomers (FFKM) are used because they can provide sealing materials with excellent plasma resistance and radical resistance. For example, Patent Document 1 discloses an uncrosslinked rubber composition containing a hydrogen-containing fluororubber, which is a crosslinkable fluoroelastomer, and a liquid hydrogen site protecting agent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-52226 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional uncrosslinked rubber compositions such as the composition described in Patent Document 1 have used liquid or oily components. In order to form a molding such as a sealing material having desired physical properties from such an uncrosslinked rubber composition, each component in the composition must be mixed uniformly. However, when a composition containing a crosslinkable fluoroelastomer and a liquid or oily component is made into a uniform composition, it takes a long time, and there is room for improvement in this respect.

[0006] One embodiment of the present invention provides an elastomeric composition that can be formed into a homogeneous composition in a short period of time. [Means for solving the problem]

[0007] As a result of intensive research by the present inventors to solve the above problems, they found that the above problems can be solved by the following configuration examples, and completed the present invention. A configuration example of the present invention is as follows.

[0008] [1] A crosslinkable fluoroelastomer (A) [wherein the elastomer (A) is a compound having no hydrosilyl groups]; a composition (B) containing at least one ethylenically unsaturated bond-containing compound selected from a perfluoro skeleton compound having an ethylenically unsaturated bond (provided that the compound is a compound other than the elastomer (A)) and a siloxane skeleton compound having an ethylenically unsaturated bond, and having a minimum torque (ML) of 0.5 kgf cm or more at 60°C as measured with a curastometer; 1. An elastomer composition comprising:

[0009] [2] The elastomer composition according to [1], wherein the elastomer (A) is a peroxide-crosslinkable fluoroelastomer. [3] The elastomer composition according to [1] or [2], wherein the elastomer (A) is a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene polymer.

[0010] [4] The elastomer composition according to any one of [1] to [3], wherein the content of the composition (B) is 0.5 to 100 parts by mass per 100 parts by mass of the elastomer (A).

[0011] [5] The elastomer composition according to any one of [1] to [4], further comprising a crosslinking agent (C). [6] The elastomer composition according to any one of [1] to [5], further comprising a crosslinking auxiliary (D).

[0012] [7] The elastomer composition according to any one of [1] to [6], wherein the content of the filler is 5 parts by mass or less per 100 parts by mass of the elastomer (A).

[0013] [8] A sealing material obtained from the elastomer composition according to any one of [1] to [7]. [9] A method for producing a sealing material, comprising a step of crosslinking the elastomer composition according to any one of [1] to [7]. Effect of the Invention

[0014] According to one embodiment of the present invention, a uniform elastomer composition can be obtained in a short period of time. Furthermore, according to one embodiment of the present invention, by using the elastomer composition, a sealing material having excellent balance of hardness, tensile strength, elongation at break, and tensile stress at 100% elongation (100% Mo) can be obtained. Furthermore, according to one embodiment of the present invention, it is possible to obtain a sealing material that is excellent in plasma resistance (radical resistance), crack resistance, compression set, etc. Therefore, the sealing material can be suitably used as a sealing material for semiconductor manufacturing equipment and a sealing material for plasma processing equipment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Elastomer composition> The elastomer composition according to one embodiment of the present invention (hereinafter also referred to as "the composition") comprises a crosslinkable fluoroelastomer (A) [wherein the elastomer (A) is a compound having no hydrosilyl group] and a composition (B) containing at least one ethylenically unsaturated bond-containing compound selected from a perfluoro skeleton compound having an ethylenically unsaturated bond (provided that the compound is a compound other than the elastomer (A)) and a siloxane skeleton compound having an ethylenically unsaturated bond, and having a minimum torque (ML) of 0.5 kgf cm or more at 60°C as measured with a curastometer; Contains:

[0016] <Crosslinkable fluoroelastomer (A)> The crosslinkable fluoroelastomer (A) is not particularly limited as long as it is a compound that does not have a hydrosilyl group (-Si-H), and any conventionally known crosslinkable fluoroelastomer can be used, but it is preferable that it is a crosslinkable fluoroelastomer other than a perfluoroelastomer. The elastomer (A) contained in the present composition may be one type or two or more types. In the present invention, "elastomer" and "rubber" have the same meaning and there is no particular distinction between them.

[0017] The elastomer (A) is also called unvulcanized fluororubber, and examples of the crosslinked type include peroxide crosslinking, polyol crosslinking, amine crosslinking, radiation crosslinking, etc. Among these, a peroxide crosslinkable fluoroelastomer is preferred, since it is not necessary to use an acid acceptor that is a source of particle generation in a plasma atmosphere, etc., and there is no risk of particle generation during use of the resulting sealing material.

[0018] Specific examples of the elastomer (A) include fluoroelastomers (FKM), tetrafluoroethylene-propylene elastomers (FEPM), and fluorine-containing thermoplastic elastomers (e.g., elastomers containing at least one type of elastomeric polymer chain segment and at least one type of non-elastomeric polymer chain segment, at least one of which is a fluorine-containing polymer chain segment).

[0019] The elastomer (A) may be one synthesized by a conventional method or a commercially available product, such as "Dai-el" manufactured by Daikin Industries, Ltd., "Viton" manufactured by Chemours, "Dyneon" manufactured by 3M, or "Tecnoflon" manufactured by Solvay.

[0020] As the elastomer (A), an elastomer capable of producing a sealing material resistant to plasma (plasma etching treatment) used in various semiconductor dry processes is preferred, and FKM having relatively good plasma resistance and excellent sealing properties is more preferred. FKM is also preferred because it is inexpensive and versatile.

[0021] The FKM is not particularly limited, but examples thereof include polymers that contain hydrogen atoms (carbon-hydrogen bonds) in the polymer main chain, and specifically, it is preferable that the FKM contains a structural unit derived from vinylidene fluoride.

[0022] The FKM is not particularly limited, but specific examples include vinylidene fluoride-hexafluoropropylene polymers; vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene polymers; vinylidene fluoride-propylene-tetrafluoroethylene polymers; ethylene-tetrafluoroethylene-perfluoroalkyl vinyl ether polymers; and vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether polymers. A suitable example of the perfluoroalkyl vinyl ether is perfluoromethyl vinyl ether.

[0023] Among these, ternary polymers are preferred because of their excellent plasma resistance, heat resistance, chemical resistance, and the like, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene polymers are more preferred.

[0024] The peroxide-crosslinkable fluoroelastomer preferably has a functional group such as an iodine group, a bromine group, a cyano group, a peroxy group, or an unsaturated group, and from the standpoint of ease of introduction of the functional group, an iodine group or a bromine group is more preferred. A fluoroelastomer having iodine and / or bromine groups can be obtained, for example, by using one or more saturated or unsaturated iodine- and / or bromine-containing compounds when synthesizing the elastomer.

[0025] Examples of the iodine- and / or bromine-containing compound include compounds represented by the following formula (1) or (2). By using the compound represented by the following formula (1), a fluoroelastomer having an iodine group and / or a bromine group on the side chain can be synthesized, and by using the compound represented by the following formula (2), a fluoroelastomer having an iodine group and / or a bromine group on the terminal can be synthesized.

[0026] CY 1 2 =CY 2 RfX (1) [Y 1 and Y 2 are each independently a fluorine atom, a hydrogen atom or a methyl group, Rf is a linear or branched fluorine-containing alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms, or a group containing an ether bond in part of the fluorine-containing alkylene group, and X is an iodine atom or a bromine atom.

[0027] Specific examples of the compound represented by formula (1) include the compounds described in WO 2009 / 119409.

[0028] I n Br m R (2) [R is a fluorohydrocarbon group having 1 to 12 carbon atoms, n and m are each independently an integer of 0 to 2, and n+m is 1 or 2.]

[0029] Specific examples of the compound represented by formula (2) include the compounds described in JP-A-2002-97329 and JP-A-2008-56739.

[0030] The fluorine content of the elastomer (A) is not particularly limited, but is preferably 55% by mass or more in terms of easiness in obtaining a desired sealing material, more preferably 60% by mass or more, even more preferably 63% by mass or more, particularly preferably 65% ​​by mass or more, and more preferably 73% by mass or less, even more preferably 71% by mass or less. The fluorine content is 19 F-NMR and 1 It can be measured or calculated by elemental analysis of fluorine using 1 H-NMR or the like, mass spectrometry (MS spectrometry), or the like. In the present invention, the fluorine content is a value rounded off to the nearest whole number.

[0031] The elastomer (A) preferably contains a crosslinkable fluoroelastomer (A1) having a fluorine content of 69 mass % or more, and a crosslinkable fluoroelastomer (A2) having a fluorine content of 55 to 68 mass %. By using at least two types of crosslinkable fluoroelastomers having a fluorine content within the above range, a uniform elastomer composition can be prepared in a short period of time, an elastomer composition with excellent moldability can be easily obtained, and a sealing material with a good balance of hardness, tensile strength, elongation at break and 100% Mo can be easily obtained.

[0032] The fluorine content of the elastomer (A1) is preferably 70% by mass or more, and preferably 73% by mass or less, more preferably 71% by mass or less. The fluorine content of the elastomer (A2) is preferably from 60 to 68 mass %, more preferably from 63 to 68 mass %, and even more preferably from 65 to 68 mass %.

[0033] The Mooney viscosity of the elastomer (A) is preferably 10 or more, more preferably 15 or more, even more preferably 18 or more, and is preferably 140 or less, more preferably 120 or less, even more preferably 80 or less, particularly preferably 60 or less. When the elastomer (A) has a Mooney viscosity within the above range, an elastomer composition having excellent moldability, particularly extrusion property, can be easily obtained. In this specification, the Mooney viscosity refers to the Mooney viscosity (ML1+10) at 121° C. measured in accordance with ASTM D 1646.

[0034] The content of the elastomer (A) in the solid content of the present composition is preferably 40% by mass or more, more preferably 50% by mass or more, and is preferably 95% by mass or less, more preferably 93% by mass or less. When the content of the elastomer (A) is within the above range, a sealing material that is excellent in chemical resistance such as plasma resistance and chemical resistance, and has a good balance of hardness, tensile strength, elongation at break and 100% Mo can be easily obtained. In this specification, the solid content refers to components other than the solvent.

[0035] The content of the elastomer (A1) in the solid content of the present composition is preferably 40% by mass or more, more preferably 50% by mass or more, and is preferably 95% by mass or less, more preferably 85% by mass or less. When the content of the elastomer (A1) is within the above range, a sealing material having excellent chemical resistance such as plasma resistance and chemical resistance can be easily obtained.

[0036] The content of the elastomer (A2) in the solid content of the present composition is preferably 2% by mass or more, more preferably 5% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less. When the content of the elastomer (A2) is within the above range, a sealing material having excellent moldability and chemical resistance in a well-balanced manner can be easily obtained.

[0037] The content of the elastomer (A1) relative to the total content of the elastomers (A1) and (A2) in the present composition is preferably 60 mass% or more, more preferably 65 mass% or more, and is preferably 95 mass% or less, more preferably 90 mass% or less. When the mass ratio of the contents of the elastomers (A1) and (A2) is within the above range, a uniform elastomer composition can be obtained in a shorter time, an elastomer composition with excellent moldability can be easily obtained, and a sealing material with a good balance of excellent hardness, tensile strength, elongation at break, and 100% Mo can be easily obtained.

[0038] <Composition (B)> The present composition comprises composition (B), which contains at least one ethylenically unsaturated bond-containing compound (hereinafter also referred to as "compound (b)") selected from a perfluoro skeleton compound having an ethylenically unsaturated bond [with the proviso that the compound is a compound other than the elastomer (A)] and a siloxane skeleton compound having an ethylenically unsaturated bond, and which has a minimum torque (ML) at 60°C measured with a curastometer of 0.5 kgf cm or more, preferably 1 kgf cm or more. By using composition (B), it is possible to easily obtain a sealing material that is excellent in plasma resistance and non-adhesiveness. Also, by using composition (B), it is possible to easily obtain a sealing material that is excellent in hardness, tensile strength, elongation at break, and 100% Mo in a well-balanced manner. The composition (B) contained in the present composition may be one type or two or more types. Incidentally, the present composition contains composition (B) means that composition (B) is used as a raw material when preparing the present composition. When the present composition contains two or more types of composition (B), it means that two or more types of composition (B) are used as raw materials when preparing the present composition.

[0039] A minimum torque (ML) of 0.5 kgf cm or more at 60°C measured with a curastometer is synonymous with the millable type commonly used in this field. Specifically, composition (B) refers to a composition in a solid form like synthetic rubber, different from liquid (paste) or oil-like compositions, and refers to a composition that is similar to unvulcanized compounded rubber of natural rubber or ordinary synthetic rubber before curing, and can be plasticized and mixed with a kneading roll machine or an internal mixer. This means that the composition (B) has a minimum torque (ML) within the above range before being mixed with the elastomer (A), the crosslinking agent (C), the crosslinking aid (D) described below, and other components. The minimum torque (ML) is specifically measured by the method described in the following examples.

[0040] The composition (B) usually contains the compound (b) and a filler such as silica. The compound (b) contained in the composition (B) may be one type or two or more types, and the filler contained in the composition (B) may be one type or two or more types. Furthermore, composition (B) may contain additives such as reactive organosilicon compounds having two or more hydrosilyl groups in the molecule (e.g., organosilicon compounds described in JP-A-2003-183402, JP-A-11-116684, etc.) and catalysts (e.g., catalysts described in JP-A-2003-183402, JP-A-11-116684, etc.).

[0041] Depending on the type of compound (b), composition (B) may be of a peroxide crosslinking type that crosslinks due to radicals generated by the decomposition of peroxide, or of an addition crosslinking type in which an ethylenically unsaturated bond and a hydrosilyl group are reacted in the presence of a catalyst. Either of these may be used in the present composition, but it is preferable to use the peroxide crosslinking type. When a peroxide-crosslinking type composition (B) is used, it is preferable to use the following peroxide-based crosslinking agent.

[0042] The content of compound (b) in composition (B) is preferably 50% by mass or more, more preferably 60% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, from the viewpoint of being able to easily obtain a sealing material that is excellent in plasma resistance and non-adhesive. The content of the filler in composition (B) is preferably 10% by mass or more, more preferably 20% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, from the viewpoints that a millable type composition can be obtained and a uniform elastomer composition can be obtained in a shorter time.

[0043] The composition (B) may be a commercially available product, such as "SIFEL" (manufactured by Shin-Etsu Chemical Co., Ltd.). As commercially available products of the composition (B), there are one-component types and two-component types, and either of these may be used.

[0044] The content of composition (B) in the present composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 25 parts by mass or less, per 100 parts by mass of elastomer (A), from the viewpoints that a uniform elastomer composition can be obtained in a shorter time and a sealing material having superior plasma resistance can be easily obtained.

[0045] When the present composition contains composition (B) and the following crosslinking agent (C), from the viewpoint of easily obtaining a sealing material having superior plasma resistance, the mass ratio of the content of composition (B) to the content of crosslinking agent (C) in the present composition (content of composition (B) / content of crosslinking agent (C)) is preferably 0.5 or more, more preferably 1 or more, and is preferably 50 or less, more preferably 20 or less.

[0046] <Compound (b)> Compound (b) is at least one compound selected from a perfluoro skeleton compound having an ethylenically unsaturated bond (hereinafter also referred to as "compound (b1)") and a siloxane skeleton compound having an ethylenically unsaturated bond (hereinafter also referred to as "compound (b2)"). Among these, compound (b) preferably contains compound (b1) from the viewpoint of easily obtaining a sealing material having superior plasma resistance.

[0047] Examples of the ethylenically unsaturated bond include alkenyl groups having 2 to 8 carbon atoms, such as vinyl, methylvinyl, allyl, propenyl, isopropenyl, butenyl, pentenyl, hexenyl, and heptenyl, vinylphenyl, (meth)acryloyl, allyloxy, styryl, and propargyl groups. Among these, alkenyl groups are preferred, alkenyl groups having 2 to 4 carbon atoms are more preferred, and vinyl groups are particularly preferred. The compound (b) may have two or more types of ethylenically unsaturated bonds.

[0048] [Compound (b1)] The compound (b1) is a compound having a perfluoro skeleton and an ethylenically unsaturated bond, and is a compound other than the elastomer (A). Examples of the compound (b1) include a compound having a perfluoropolyether structure with an ethylenically unsaturated bond, and a compound having a perfluoroalkylene structure with an ethylenically unsaturated bond. Among these, a compound having a perfluoropolyether structure with an ethylenically unsaturated bond (hereinafter also referred to as "compound (b1-1)") is preferred.

[0049] ·Compound (b1-1) The compound (b1-1) is preferably a perfluoropolyether having two or more ethylenically unsaturated bonds in one molecule.

[0050] Suitable examples of compound (b1-1) include the compounds described in JP-A-2003-183402, JP-A-11-116684, JP-A-11-116685, and JP-A-2015-67737.

[0051] An example of the compound (b1-1) is a compound represented by the following formula (1). Z 1 -(X) p -(Rf-Q) a -Rf-(X) p -Z 2 (1)

[0052] X is independently -CH 2 -, -CH 2 O-, -CH 2 OCH 2 -, *-Si(R 2 ) 2 -Ph- (Ph: phenylene group), *-Y-NR 1 SO 2 -or*-Y-NR 1 -CO-(Y is -CH 2 -or*-Si(R 2 ) 2 -Ph-. In addition, the * portion is Z1 or Z 2 ). Rf is a divalent perfluoropolyether group (a divalent perfluorooxyalkylene group). p is independently 0 or 1. a is an integer of 0 or more, preferably an integer of 0 to 10, and more preferably an integer of 0 to 6. Q is a group represented by the following formula (2), (3) or (4).

[0053] R 2 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, and examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, and decyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, and hexenyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms or the like (e.g., fluorine-substituted alkyl groups such as chloromethyl, chloropropyl, bromoethyl, 3,3,3-trifluoropropyl, and 6,6,6,5,5,4,4,3,3-nonafluorohexyl).

[0054] R 1 is a hydrogen atom or the R 2 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, similar to the groups exemplified as R 2Examples of the alkyl group include alkyl groups such as a methyl group, an ethyl group, a propyl group, and an isopropyl group; cycloalkyl groups such as a cyclohexyl group; alkenyl groups such as a vinyl group and an allyl group; aryl groups such as a phenyl group and a tolyl group; and groups in which a portion of the hydrogen atoms of these groups have been substituted with a halogen atom or the like (e.g., fluorine-substituted alkyl groups such as a chloromethyl group, a chloropropyl group, a 3,3,3-trifluoropropyl group, and a 6,6,6,5,5,4,4,3,3-nonafluorohexyl group).

[0055] Z 1 and Z 2 are each independently an ethylenically unsaturated bond-containing group, -Si(ethylenically unsaturated bond-containing group)(R') 2 may be also possible. The ethylenically unsaturated bond-containing group is preferably a monovalent alkenyl group, more preferably a monovalent alkenyl group having 2 to 4 carbon atoms, and particularly preferably a monovalent vinyl group. R' is independently a substituted or unsubstituted monovalent hydrocarbon group, and specific examples include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, pentyl, and hexyl; aryl groups such as phenyl, tolyl, and xylyl; and halogenated alkyl groups such as 3-chloropropyl and 3,3,3-trifluoropropyl. Among these, alkyl groups having 1 to 5 carbon atoms are preferred.

[0056] [ka]

[0057] In formulas (2) to (4), X, p and R 1 represents X, p and R in the formula (1). 1 Synonymous with R. 3 and R 4 are each independently a substituted or unsubstituted divalent hydrocarbon group which may have one or more atoms selected from oxygen atoms, nitrogen atoms, silicon atoms, and sulfur atoms interposed in the bond, and R in formula (2) 3 and R in formula (3)4 may each independently be a group represented by the following formula (5) or (6):

[0058] [ka]

[0059] In formulas (5) and (6), R 5 is a substituted or unsubstituted monovalent hydrocarbon group, R 6 is a group containing one or more atoms selected from a carbon atom, an oxygen atom, a nitrogen atom, a silicon atom and a sulfur atom.

[0060] R 3 and R 4 Although there are no particular limitations on the divalent hydrocarbon group, it is preferred that the divalent hydrocarbon group have 1 to 20 carbon atoms, and more preferably 2 to 12 carbon atoms. Specific examples of the divalent hydrocarbon group include alkylene groups such as methylene, ethylene, propylene, methylethylene, butylene, and hexamethylene groups, cycloalkylene groups such as cyclohexylene groups, arylene groups such as phenylene, tolylene, xylylene, naphthylene, and biphenylene groups, groups in which a portion of the hydrogen atoms of these groups have been substituted with halogen atoms or the like, and combinations of these substituted or unsubstituted alkylene and arylene groups.

[0061] -(X) p -(Rf-Q) a -Rf-(X) p - is -(OR 7 ) n -[R 7 represents a perfluoroalkanediyl group, and n represents an integer of 2 or more. 7 may be the same or different.

[0062] R 7 Examples of the perfluoroalkanediyl group represented by the formula (I) include C m F 2m(m is an integer of 2 or more), which may be linear or branched. The number of carbon atoms in the perfluoroalkanediyl group (i.e., m) is, for example, 1 to 10, preferably 2 to 6, more preferably 2 to 4, and particularly preferably 2 to 3.

[0063] n may be 2 or more, for example, 10 or more, preferably 40 or more, and more preferably 70 or more. Also, n is, for example, 300 or less, preferably 200 or less, and more preferably 150 or less.

[0064] -(OR 7 ) n - may be the same group as Rf below.

[0065] The compound represented by the formula (1) is preferably a compound represented by the following formula (1-1). CH 2 =CH-(X) p -(Rf-Q) a -Rf-(X) p -CH=CH 2 (1-1) [The definition of each symbol in formula (1-1) is the same as the definition of each symbol in formula (1)]

[0066] The compound represented by the formula (1-1) is preferably a compound in which a is 0, and in this case, is represented by the following formula (1-1-1). CH 2 =CH-(X) p -Rf-(X) p -CH=CH 2 (1-1-1) [The definition of each symbol in formula (1-1-1) is the same as the definition of each symbol in formula (1)]

[0067] Specific examples of Rf include the following groups. -[CF(Z)OCF 2 ] p -(CF 2 ) r -[CF 2 OCF(Z)] q- (Z is a fluorine atom or -CF 3 where p, q and r are integers satisfying p≧1, q≧1, 2≦p+q≦200, preferably 2≦p+q≦110, and 0≦r≦6. -CF 2 CF 2 OCF 2 -(CF(CF 3 )OCF 2 ) s -(CF 2 ) r -(CF 2 OCF(CF 3 )) t -CF 2 OCF 2 CF 2 - (r, s, and t are integers satisfying 0≦r≦6, s≧0, t≧0, 0≦s+t≦200, and preferably 2≦s+t≦110.) -CF(Z)-(OCF(Z)CF 2 ) u -(OCF 2 ) v -OCF(Z)- (Z is a fluorine atom or -CF 3 where u and v are integers satisfying 1≦u≦100 and 1≦v≦50. -CF 2 CF 2 -[OCF 2 CF 2 CF 2 ] w -OCF 2 CF 2 - (where w is an integer satisfying 1≦w≦100.)

[0068] [Compound (b2)] Compound (b2) is a compound of a siloxane skeleton having an ethylenically unsaturated bond, and is preferably a polysiloxane having two or more ethylenically unsaturated bonds in one molecule, and is preferably an organopolysiloxane having two or more ethylenically unsaturated bonds in one molecule and having an organic group bonded to a silicon atom. The bonding position of the ethylenically unsaturated bond is not particularly limited.

[0069] Examples of the organic group bonded to a silicon atom include the above-mentioned ethylenically unsaturated bond, linear alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, aralkyl groups, and halogenated alkyl groups. Examples of the linear alkyl group include groups having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a hexyl group, an octyl group, and a decyl group. Examples of the branched alkyl group include groups having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, such as an isopropyl group, an isobutyl group, a t-butyl group, and a 2-ethylhexyl group. Examples of the cyclic alkyl group include groups having 3 to 20 carbon atoms, such as a cyclopentyl group and a cyclohexyl group. Examples of the aryl group include groups having 6 to 20 carbon atoms, such as a phenyl group and a tolyl group. Examples of the aralkyl group include groups having 7 to 20 carbon atoms, such as a benzyl group, a 2-phenylethyl group, and a 2-methyl-2-phenylethyl group. Examples of the halogenated alkyl group include groups having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, such as a 3,3,3-trifluoropropyl group, a 2-(nonafluorobutyl)ethyl group, and a 2-(heptadecafluorooctyl)ethyl group.

[0070] The organic group bonded to the silicon atom is preferably a linear alkyl group, an alkenyl group, or an aryl group, more preferably a linear alkyl group, an alkenyl group, or an aryl group having 1 to 6 carbon atoms, and particularly preferably a methyl group, a vinyl group, or a phenyl group.

[0071] The molecular structure of the compound (b2) is not particularly limited, and may be, for example, linear, branched, partially branched linear, or dendritic (dendrimer), and is preferably linear or partially branched linear. The compound (b2) may be a single polymer having these molecular structures, a copolymer having these molecular structures, or a mixture of two or more of these polymers.

[0072] Examples of compound (b2) include dimethylpolysiloxanes capped at both molecular chain terminals with dimethylvinylsiloxy groups, dimethylpolysiloxanes capped at both molecular chain terminals with methylphenylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers capped at both molecular chain terminals with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers capped at both molecular chain terminals with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers capped at both molecular chain terminals with silanol groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped at both molecular chain terminals with silanol groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped at both molecular chain terminals with trimethylsiloxy groups, methyl(3,3,3-trifluoropropyl)polysiloxanes capped at both molecular chain terminals with dimethylvinylsiloxy groups, 3 ) 3 SiO 1 / 2 Siloxane units represented by the formula: (CH 3 ) 2 (CH 2 =CH)SiO 1 / 2 Siloxane units represented by the formula: CH 3 SiO 3 / 2 Siloxane units represented by the formula: (CH 3 ) 2 SiO 2 / 2 and a compound represented by the following formula (7).

[0073] [ka] [In formula (7), R 1 are each independently an unsubstituted or substituted monovalent hydrocarbon group; R 2 are 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. 1 and R 2 At least two of the above-mentioned formulas contain the ethylenically unsaturated bond.]

[0074] In formula (7), R1 are each independently an unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 10 carbon atoms, examples of which include the same groups as those exemplified as the organic group bonded to the silicon atom. Among these, a monovalent hydrocarbon group having 1 to 6 carbon atoms is preferred, and an alkenyl group, an aryl group, or an alkyl group having 1 to 3 carbon atoms is more preferred.

[0075] R in Equation (7) 2 Examples of the alkyl group and alkenyl group in the above formula include the same straight-chain alkyl group, branched-chain alkyl group, cyclic alkyl group, and alkenyl group as those exemplified as the organic group bonded to the silicon atom. R in Equation (7) 2 Examples of the alkoxyalkyl group in the formula include groups having 2 to 10 carbon atoms, such as a methoxyethyl group and a methoxypropyl group. R in Equation (7) 2 Examples of the acyl group in the formula include groups having 2 to 10 carbon atoms, such as an acetyl group and an octanoyl group.

[0076] In the formula (7), b is preferably an integer of 10 to 50, and a is preferably 3.

[0077] <Crosslinking agent (C)> The elastomer (A) can be crosslinked without using the crosslinking agent (C). However, it is preferable that the composition contains a crosslinking agent (C) appropriate to the type of elastomer (A) used, from the viewpoint of easily obtaining a sealing material that is sufficiently crosslinked and has a well-balanced excellent property in terms of hardness, tensile strength, elongation at break, and 100% Mo. When the present composition contains a crosslinking agent (C), the crosslinking agent (C) contained in the present composition may be one type or two or more types.

[0078] As the crosslinking agent (C), any conventionally known crosslinking agent can be used without any particular limitation, and may be appropriately selected depending on the type of elastomer (A) used. For example, when FKM is used, examples of the crosslinking agent include peroxide-based crosslinking agents, polyamine-based crosslinking agents, polyol-based crosslinking agents, and triazine-based crosslinking agents.

[0079] Among these, peroxide-based crosslinking agents are preferred because there is no need to incorporate an acid acceptor such as magnesium oxide or calcium hydroxide, which can be a source of particle generation in a plasma atmosphere, into the composition, and there is no risk of particle generation during use of the resulting sealing material.

[0080] Examples of peroxide-based crosslinking agents include 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, di-t-butyl peroxide, t-butyldicumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, and t-butylperoxyisopropyl. Examples of peroxyalkylene oxides include propyl carbonate, di-(4-t-butylcyclohexyl)peroxydicarbonate, p-chlorobenzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, α,α-bis(t-butylperoxy)-p-diisopropylbenzene, t-butylperoxybenzene, and t-butylperoxymaleic acid. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, benzoyl peroxide, and α,α'-bis(t-butylperoxy-m-isopropyl)benzene are preferred, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane is more preferred.

[0081] When the present composition contains a crosslinking agent (C), the content of the crosslinking agent (C) in the present composition is preferably 0.2 to 4 parts by mass, more preferably 0.2 to 2.5 parts by mass, per 100 parts by mass of the elastomer (A), from the viewpoints that the crosslinking reaction proceeds sufficiently and a sealing material having excellent and well-balanced properties in hardness, tensile strength, elongation at break, and 100% Mo can be easily obtained.

[0082] <Crosslinking agent (D)> In the present composition, the crosslinking agent (C) may be used alone, but when the crosslinking agent (C) is used, it is preferable to use a crosslinking auxiliary (D). As the crosslinking auxiliary (D), a known crosslinking auxiliary may be selected according to the type of the crosslinking agent (C). When the present composition contains a crosslinking auxiliary (D), the crosslinking auxiliary (D) contained in the present composition may be one type or two or more types.

[0083] For example, examples of crosslinking assistants that can be used when using a peroxide-based crosslinking agent include triallyl isocyanurate, triallyl cyanurate, trimethallyl isocyanurate, triallyl formal, triallyl trimellitate, N,N'-m-phenylene bismaleimide, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalamide, polyfunctional (meth)acrylates such as ethylene glycol di(meth)acrylate and trimethylolpropane tri(meth)acrylate, and compounds capable of co-crosslinking by radicals (polyfunctional monomers), metal salts of higher carboxylic acids, polyhydric alcohol (meth)acrylates, and metal (meth)acrylic acid salts. Among these, triallyl isocyanurate is preferred because it has excellent reactivity, excellent heat resistance, and allows a sealing material having high hardness and high modulus to be easily obtained.

[0084] When the present composition contains a crosslinking aid (D), the content of the crosslinking aid (D) in the present composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 4 parts by mass or more, relative to 100 parts by mass of the elastomer (A), from the viewpoints that the crosslinking reaction proceeds sufficiently and a sealing material having an excellent balance of hardness, tensile strength, elongation at break, and 100% Mo can be easily obtained, and is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 6 parts by mass or less. In particular, in order to suppress cracks that may occur in the sealing material under a plasma atmosphere or the like, a radiation-crosslinked sealing material (radiation-treated product) is preferred. In this case, the content of the crosslinking aid (D) in the present composition is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, and preferably 7 parts by mass or less, more preferably 6 parts by mass or less, per 100 parts by mass of the elastomer (A), from the viewpoint that a sealing material with higher hardness and higher modulus can be easily obtained.

[0085] The mass ratio of the content of the crosslinking auxiliary (D) to the content of the crosslinking agent (C) in the composition (content of crosslinking auxiliary (D) / content of crosslinking agent (C)) is preferably 2 or more, more preferably 4 or more, and even more preferably 6 or more, from the viewpoints that the crosslinking agent (C) can be reacted without excess or deficiency to easily obtain a sealing material exhibiting desired physical properties, in particular, a sealing material with higher hardness and higher modulus can be easily obtained, and is preferably 30 or less, more preferably 20 or less.

[0086] <Other ingredients> In addition to the above-mentioned components, the present composition may contain other components that have been conventionally known and have been blended into sealing materials, if necessary, within the scope of not impairing the effects of the present invention. Examples of such other components include reactive organosilicon compounds having two or more hydrosilyl groups in the molecule, catalysts, polyol compounds, acid acceptors such as magnesium oxide and calcium hydroxide, organic pigments such as anthraquinone pigments, perylene pigments, and dioxazine pigments, plasticizers, processing aids, vulcanization accelerators, antioxidants, antioxidants, inorganic fillers, and organic fillers. The other components may each be used alone or in combination of two or more.

[0087] [Reactive organosilicon compounds] Suitable examples of the reactive organosilicon compound include the same organosilicon compounds as those described in JP-A Nos. 2003-183402 and 11-116684.

[0088] [catalyst] Suitable examples of the catalyst include the same catalysts as those described in JP-A Nos. 2003-183402 and 11-116684.

[0089] [Polyol compounds] By using the polyol-based compound, a sealing material having excellent crack resistance in a plasma environment can be easily formed without impairing the performance of the sealing material.

[0090] As the polyol-based compound, a wide variety of known compounds can be used, but bisphenols are preferred because they can easily provide a sealing material that is particularly excellent in crack resistance. Examples of the bisphenols include 2,2-bis(4-hydroxyphenyl)perfluoropropane (bisphenol AF), 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), and bis(4-hydroxyphenyl)sulfone (bisphenol S), and may also be salts of these compounds such as alkali metal salts and alkaline earth metal salts. Among these, bisphenol AF and bisphenol A are preferred, and bisphenol AF is more preferred because a sealing material that is particularly excellent in crack resistance can be easily obtained.

[0091] When the present composition contains a polyol-based compound, the content of the polyol-based compound in the present composition is preferably 0.1 to 3 parts by mass, more preferably 0.1 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the elastomer (A), from the viewpoints that a sealing material having excellent crack resistance, small compression set, and excellent vulcanization rate can be easily obtained.

[0092] [Organic pigments] Suitable examples of the organic pigment include organic pigments similar to those described in WO 2016 / 043100, Japanese Patent No. 4720501, WO 2004 / 094527, and the like.

[0093] [Filling material] The inorganic filler and organic filler (hereinafter collectively referred to simply as "filler") are particulate (powder) components other than the composition (B), the crosslinking agent (C) and the crosslinking auxiliary (D). Examples of the inorganic filler include carbon black, silica, barium sulfate, titanium oxide, and aluminum oxide. Examples of the organic filler include fluororesins such as PTFE, PFA, FEP, ETFE, and PVDF, polyethylene resins, polyimide resins, silicone resins, and melamine resins.

[0094] When the present composition is used for producing a sealing material in which generation of particles is a problem, such as in a plasma atmosphere, the content of the filler is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less, per 100 parts by mass of the elastomer (A).

[0095] <Method of manufacturing the present composition> The present composition can be produced by mixing (kneading) the elastomer (A) and the composition (B), and preferably by mixing (kneading) the elastomer (A), the composition (B), the crosslinking agent (C), the crosslinking auxiliary (D), and, if necessary, the other components described above. The order of mixing the elastomer (A) with additives such as the composition (B), the crosslinking agent (C), the crosslinking aid (D), and other components is not particularly limited, and they may be mixed (kneaded) sequentially in any order, or may be mixed (kneaded) all at once. However, it is preferable to mix (knead) them sequentially so that each component is uniform.

[0096] In the mixing (kneading) process, a conventionally known mixer (kneader) can be used, and examples of such a mixer include an open roll, a Banbury mixer, a twin-screw roll, and a kneader. Furthermore, during the mixing (kneading) process, the components may be mixed (kneaded) under heating or cooling, if necessary, depending on the mixer (kneader).

[0097] <Sealing material> A sealing material according to one embodiment of the present invention (hereinafter also referred to as "the present sealing material") is a sealing material obtained from the present composition. The present sealing material is obtained from the present composition and therefore has a good balance of excellent hardness, tensile strength, elongation at break, and 100% Mo, and further has excellent plasma resistance (radical resistance), crack resistance, compression set, and the like.

[0098] The present sealing material can be used, for example, as a gasket or packing for various components, and because it exerts the above-mentioned effects in particular, it can be suitably used in semiconductor manufacturing equipment and plasma processing equipment, particularly in driving parts such as gate valves used in the openings of plasma processing chamber units. The shape and other properties of the sealing material may be appropriately selected depending on the application.

[0099] <Method of manufacturing the present sealing material> Specifically, the present sealing material can be produced by molding the present composition. However, it is preferable that the present sealing material is a crosslinked product obtained by a method including a step of crosslinking the present composition (crosslinking step), in view of the ease of obtaining a sealing material that is excellent in plasma resistance (radical resistance), crack resistance, non-stickiness, etc., and that has a well-balanced excellentness in hardness, tensile strength, elongation at break, and 100% Mo.

[0100] When forming a sealing material from the present composition, it is preferable to carry out a separating step in order to improve the efficiency of the molding operation, reduce the defective rate, etc. This separating step is usually carried out using a roll or the like, and is usually also a step of preliminarily forming the present composition into a sheet shape.

[0101] The sheet obtained in the extrusion step is preferably preformed into a desired shape of a sealing material before the crosslinking step. In this preforming, the desired sealing material shape may be formed directly from the sheet obtained in the separating process, or the sheet obtained in the separating process may be cut or extruded into a rope-like shape (which also has the same meaning as a ribbon-like or noodle-like shape) or the like, and the resulting rope-like material may be formed into the desired sealing material shape.

[0102] More preferably, the crosslinking step includes a primary crosslinking step and a secondary crosslinking step. The crosslinking step is preferably carried out using the sealing material having a desired shape obtained by the preforming step.

[0103] The primary crosslinking step is preferably a step of heating and pressurizing the product of the desired sealing material shape obtained by the preforming step. Specifically, for example, the preformed material is placed in a mold and crosslinked by a hot press or the like under a pressure of about 2 to 15 MPa at a temperature of, for example, 150 to 200°C for, for example, about 5 to 20 minutes.

[0104] The secondary crosslinking step is preferably a step of heating the molded body obtained in the primary crosslinking step, and specifically includes a step of heating the molded body at normal pressure to reduced pressure using various ovens, preferably a vacuum oven, at a temperature of, for example, 150 to 300°C for 1 to 24 hours, more preferably for about 3 to 24 hours. This secondary crosslinking process can promote crosslinking, and even if unreacted components remain after the primary crosslinking process, the unreacted components can be decomposed and evaporated, resulting in a sealing material that emits less gas.

[0105] In the method for producing the present sealant, a step of irradiating with radiation (radiation irradiation step) may be carried out after the crosslinking step, in order to more easily suppress cracks that may occur in the sealant in a plasma atmosphere, etc. The present sealant obtained through this radiation irradiation step can be said to be a radiation-treated product.

[0106] The radiation to be irradiated in the radiation irradiation step is not particularly limited as long as it can crosslink the elastomer (A), and examples thereof include X-rays, gamma rays, electron beams, proton beams, neutron beams, heavy particle beams, alpha rays, and beta rays. Among these, gamma rays and electron beams are preferred. The radiation to be irradiated may be of one type alone or of two or more types.

[0107] When irradiating with radiation, it is desirable to irradiate with radiation so that the absorbed dose is preferably 1 to 120 kGy, more preferably 20 to 100 kGy. By irradiating with radiation in such an amount, it is possible to reduce unreacted components that may become particles or released gas, and it is possible to easily obtain a sealing material that is excellent in plasma resistance, crack resistance, etc., without excessively lowering the molecular weight of the elastomer (A). The radiation exposure step may be carried out in two or more stages by changing the conditions.

[0108] The radiation may be applied in air, but if oxygen is present during radiation application, the crosslinking reaction may be inhibited, and the mechanical strength of the sealant may decrease, and the surface of the sealant may become sticky. For this reason, the radiation application step is preferably performed in an atmosphere of an inert gas such as nitrogen or argon. EXAMPLES

[0109] Next, the present invention will be described in more detail by showing examples, but the present invention is not limited to these.

[0110] [Example 1] 100 parts by mass of Daiel G912 (manufactured by Daikin Industries, Ltd., fluorine content: 71% by mass, hereinafter also referred to as "crosslinkable fluoroelastomer 1") was wound around a 6-inch roll with the roll temperature set to 60°C at a rotation speed of 20 ppm, and then cut back. 2 parts by mass of X-71-906 (manufactured by Shin-Etsu Chemical Co., Ltd., millable type containing a compound with a perfluoro skeleton having an ethylenically unsaturated bond, hereinafter also referred to as "composition B1") were added thereto, and the mixture was kneaded until the appearance became uniform.

[0111] The minimum torque (ML) of composition B1 was measured under the following conditions using a Curastometer TYPER (for rubber) manufactured by JSR Trading Co., Ltd., and was found to be 3.74 kgf·cm. Sample: 10g Temperature: 60℃ Amplitude angle: ±3° Measurement time: 10 minutes

[0112] [Example 2] 100 parts by mass of X-71-906 and 25 parts by mass of KE-1830 (manufactured by Shin-Etsu Chemical Co., Ltd., containing a compound with a siloxane skeleton having an ethylenically unsaturated bond) were kneaded together to obtain composition B2. The minimum torque (ML) of the obtained composition B2 was measured by the same method as above and was found to be 2.43 kgf cm. The composition was kneaded in the same manner as in Example 1, except that the composition B2 was used instead of the composition B1, until the appearance became uniform.

[0113] [Comparative Example 1] The composition was kneaded in the same manner as in Example 1 until the appearance was uniform, except that SIFEL 3590-N (manufactured by Shin-Etsu Chemical Co., Ltd., one-component liquid type containing a perfluoro skeleton compound having an ethylenically unsaturated bond) was used instead of composition B1.

[0114] [Comparative Example 2] The composition was kneaded in the same manner as in Example 1 until the appearance was uniform, except that 1 part by mass of SIFEL 8070A (manufactured by Shin-Etsu Chemical Co., Ltd., oil type) and 1 part by mass of SIFEL 8070B (manufactured by Shin-Etsu Chemical Co., Ltd., oil type) were used instead of 2 parts by mass of composition B1. At least one of SIFEL 8070A and SIFEL 8070B contains a compound having a perfluoro skeleton with an ethylenically unsaturated bond.

[0115] In Examples 1 and 2 and Comparative Examples 1 and 2, the time required for kneading until the appearance became uniform was measured and evaluated according to the following criteria. The results are shown in Table 1. ○: Time required for mixing until the appearance was uniform was within 10 minutes △: The time required to knead until the appearance was uniform was more than 10 minutes but less than 30 minutes. ×: The time required to knead until the appearance was uniform exceeded 30 minutes.

[0116] [Table 1]

[0117] [Example 3] 100 parts by mass of the crosslinkable fluoroelastomer 1 was wound around a 6-inch roll with the roll temperature set at 60°C at a rotation speed of 20 ppm, and then cut back. 2 parts by mass of composition B1 were added thereto and kneaded until the appearance became uniform. Next, the roll was cut back, and 6 parts by mass of TAIC (manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate) were added thereto and kneaded until the appearance became uniform. Next, the roll was cut back, and 1 part by mass of Perhexa 25B (manufactured by NOF Corporation) was added thereto and kneaded until the appearance became uniform. It should be noted that even when 100 parts by mass of composition B1 was used per 100 parts by mass of crosslinkable fluoroelastomer 1, kneading was possible.

[0118] [Example 4] In Example 3, composition B2 obtained in the same manner as in Example 2 was used instead of composition B1, and the mixture was kneaded in the same manner as in Example 3 until it became uniform in appearance.

[0119] [Comparative Example 3] The composition was kneaded in the same manner as in Example 3, except that SIFEL 3590-N was used instead of composition B1, until the composition had a uniform appearance. When SIFEL 3590-N was used, the maximum amount of SIFEL 3590-N that could be kneaded with 100 parts by mass of the crosslinkable fluoroelastomer 1 was 50 parts by mass.

[0120] [Comparative Example 4] The mixture was kneaded in the same manner as in Example 3, except that 1 part by mass of SIFEL 8070A and 1 part by mass of SIFEL 8070B were used instead of 2 parts by mass of composition B1, until the appearance became uniform. When SIFEL 8070A and B were used, the total amount of SIFEL 8070A and B that could be kneaded with respect to 100 parts by mass of the crosslinkable fluoroelastomer 1 was a maximum of 10 parts by mass.

[0121] In Examples 3 and 4 and Comparative Examples 3 and 4, the time required for kneading until the appearance became uniform was measured and evaluated according to the following criteria. The results are shown in Table 2. ○: Time required for mixing until the appearance was uniform was within 60 minutes △: The time required to knead until the appearance was uniform was more than 60 minutes but less than 90 minutes. ×: The time required to knead until the appearance was uniform exceeded 90 minutes.

[0122] [Table 2]

[0123] [Example 5] A block of elastomer composition was obtained by uniformly kneading 70 parts by mass of crosslinkable fluoroelastomer 1, 30 parts by mass of Tecnoflon P757 (manufactured by Solvay, fluorine content: 67% by mass, hereinafter also referred to as "crosslinkable fluoroelastomer 2"), 2 parts by mass of composition B1, 6 parts by mass of TAIC, and 1 part by mass of Perhexa 25B with a roll.

[0124] The obtained bulk elastomer composition was filled into a mold and press-molded using a compression vacuum press at 170°C for 10 minutes under a pressure of 5 MPa (primary crosslinking). The press-molded sheet was then heated in a vacuum oven (vacuum degree: 50 Pa) at 200°C for 16 hours under reduced pressure (secondary crosslinking). The following physical properties in normal state of the obtained molded product were measured, and the results are shown in Table 3.

[0125] <Normal physical properties> As normal physical properties, Shore A hardness was measured in accordance with JIS K 6253:2012, and tensile strength, elongation at break, and tensile stress at 100% elongation (100% Mo) were measured in accordance with JIS K 6251:2017.

[0126] [Examples 6 to 9] Various evaluations were carried out in the same manner as in Example 5, except that the amount of composition B1 used in Example 5 was changed to the amount shown in Table 3. The results are shown in Table 3.

[0127] [Table 3]

[0128] [Examples 10 to 14] A lump of elastomer composition was obtained in the same manner as in Example 5, except that the amount of composition B1 used was changed to the amount shown in Table 4.

[0129] The obtained bulk elastomer composition was filled into a mold and press molded at 170°C for 10 minutes under a pressure of 5 MPa using a compression vacuum press (primary crosslinking), and then the press-molded sheet was heated at 200°C for 16 hours under reduced pressure in a vacuum oven (vacuum degree: 50 Pa) (secondary crosslinking).Then, the secondary crosslinked sheet was irradiated with radiation so that the absorbed dose was 80 kGy, to obtain a molded product. The normal physical properties of the obtained molded product were measured, and the results are shown in Table 4.

[0130] <Plasma resistance> Furthermore, the plasma resistance (mass reduction rate) of the obtained molded article was measured. Specifically, the measurement was performed as follows. A flat-plate plasma processing device with an electrode diameter of φ300 mm and an electrode distance of 50 mm was used, and RF 500 W and CF 4 Gas flow rate: 50 sccm, O 2 The resulting molded body was irradiated with plasma for 3 hours under conditions of a gas flow rate of 150 sccm and a degree of vacuum of 1 torr. The obtained molded body was placed 6 cm away from the plasma electrode. Next, the mass of the molded body was measured before and after the test, and the mass reduction rate (%) was calculated using the following formula to evaluate the plasma resistance. The smaller the mass reduction rate, the better the plasma resistance. Mass reduction rate (%) = [(mass of molded body before test - mass of molded body after test) / mass of molded body before test] x 100

[0131] [Table 4]

[0132] [Example 15] A molded article was obtained in the same manner as in Example 10, except that the amount of Perhexa 25B used was changed to 0.5 parts by mass. The normal physical properties and plasma resistance of the obtained molded article were measured. The results are shown in Table 5.

[0133] [Comparative Example 5] A molded article was obtained in the same manner as in Example 15, except that composition B1 was not used. The normal physical properties and plasma resistance of the obtained molded article were measured. The results are shown in Table 5.

[0134] [Table 5]

Claims

1. A crosslinkable fluoroelastomer (A) which is a compound having no hydrosilyl group; A composition (B) which contains a perfluoro skeleton compound having an ethylenically unsaturated bond, which is a compound other than the elastomer (A), has a minimum torque of 0.5 kgf cm or more at 60° C., as measured under the following conditions using a Curastometer TYPEPER (for rubber) manufactured by JSR Trading Co., Ltd., and is a millable type. Contains The content of the composition (B) is 0.5 to 50 parts by mass relative to 100 parts by mass of the elastomer (A). Elastomeric composition. (conditions) Sample: 10 g Temperature: 60℃ Amplitude angle: ±3° Measurement time: 10 minutes

2. 2. The elastomeric composition of claim 1, wherein the elastomer (A) is a peroxide crosslinkable fluoroelastomer.

3. 3. The elastomer composition according to claim 1, wherein the elastomer (A) is a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene polymer.

4. The elastomer composition according to any one of claims 1 to 3, further comprising a crosslinking agent (C).

5. The elastomer composition according to any one of claims 1 to 4, further comprising a crosslinking coagent (D).

6. The elastomer composition according to any one of claims 1 to 5, wherein the content of the filler is 5 parts by mass or less per 100 parts by mass of the elastomer (A).

7. A sealing material obtained from the elastomer composition according to any one of claims 1 to 6.

8. A method for producing a sealing material, comprising a step of crosslinking the elastomer composition according to any one of claims 1 to 6.

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