Elastomeric composition, sealing material and method for manufacturing a sealing material

Abstract

An embodiment of the present application relates to an elastomer composition, a sealing material, or a production method of a sealing material, the elastomer composition comprising a cross-linkable fluorine-containing elastomer (A) other than a perfluoroelastomer, a compound (B) containing an ethylenic unsaturated bond, a cross-linking agent (C), and a cross-linking aid (D), the compound (B) containing an ethylenic unsaturated bond comprising at least one 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, the content of the cross-linking aid (D) being 5 or more in mass ratio relative to the content of the cross-linking agent (C).

Description

Technical Field

[0001] One embodiment of the present invention relates to an elastomer composition, a sealing material, or a method of manufacturing a sealing material. Background Technology

[0002] Sealing materials have long been widely used for various purposes. Among these applications, one example of the application that places the greatest load on sealing materials is the sealing materials used in semiconductor manufacturing equipment.

[0003] In order to obtain sealing materials with excellent plasma resistance or free radical resistance, cross-linked fluorinated elastomers such as fluorinated elastomers (FKM) and perfluorinated elastomers (FFKM) are used as such sealing materials.

[0004] For example, Patent Document 1 discloses an uncrosslinked rubber composition comprising hydrofluororubber, a hydrogen site protectant, and a thermal crosslinking agent.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-52226 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] However, as a sealing material formed from existing elastomer compositions such as those described in Patent Document 1, especially for applications where particle generation is a problem in plasma atmospheres, there is room for improvement in terms of tensile stress (100% Mo) at 100% elongation, especially for sealing materials formed from existing elastomer compositions such as those described in Patent Document 1.

[0010] One embodiment of the present invention provides an elastomer composition capable of forming a sealing material with high tensile stress (100% Mo) at 100% elongation.

[0011] Technical solutions adopted to solve technical problems

[0012] In order to solve the above-mentioned technical problems, the inventors conducted in-depth research and found that the above-mentioned problems could be solved by the following configuration example, thereby completing the present invention.

[0013] The structure of the present invention is described below.

[0014] [1] An elastomer composition comprising a crosslinked fluorinated elastomer (A) other than a perfluorinated elastomer, a compound containing an olefinic unsaturated bond (B), a crosslinking agent (C), and a crosslinking aid (D),

[0015] The compound (B) containing olefinic unsaturated bonds comprises at least one selected from compounds with a perfluorinated skeleton having olefinic unsaturated bonds and compounds with a siloxane skeleton having olefinic unsaturated bonds.

[0016] The mass ratio of the content of the crosslinking aid (D) to the content of the crosslinking agent (C) is 5 or more.

[0017] [2] The elastomer composition as described in [1], wherein the fluorinated elastomer (A) is a peroxide-crosslinkable fluorinated elastomer.

[0018] [3] The elastomer composition as described in [1] or [2], wherein the content of the olefinic unsaturated compound (B) is 0.5 to 50 parts by mass relative to 100 parts by mass of the elastomer (A).

[0019] [4] The elastomer composition as described in any one of [1] to [3], wherein the content of the crosslinking aid (D) is 1 to 10 parts by mass relative to 100 parts by mass of the elastomer (A).

[0020] [5] The elastomer composition as described in any one of [1] to [4], wherein the content of filler material is 5 parts by mass or less relative to 100 parts by mass of the fluorinated elastomer (A).

[0021] [6] A sealing material, which is a radioactive crosslinker of an elastomer composition as described in any one of [1] to [5].

[0022] [7] A method for manufacturing a sealing material, comprising a step of irradiating the elastomeric composition or a crosslinked product of the elastomeric composition as described in any one of [1] to [5] with radiation.

[0023] Invention Effects

[0024] According to one embodiment of the present invention, a sealing material with 100% Mo can be formed, and in particular, a sealing material exhibiting excellent hardness, tensile strength, and 100% Mo with a good balance can be obtained. Furthermore, according to one embodiment of the present invention, a sealing material with excellent plasma resistance (free radical resistance), crack resistance, and compression set can be obtained. Therefore, this sealing material is suitable for use as a sealing material for semiconductor manufacturing apparatus and for plasma processing apparatus. Detailed Implementation

[0025] Elastomer Compositions

[0026] An elastomer composition according to one embodiment of the present invention (hereinafter also referred to as "the composition") comprises a crosslinked fluorinated elastomer (A) other than a perfluorinated elastomer, a compound containing an olefinic unsaturated bond (B), a crosslinking agent (C), and a crosslinking aid (D).

[0027] The compound (B) containing olefinic unsaturated bonds comprises at least one selected from compounds with a perfluorinated skeleton having olefinic unsaturated bonds and compounds with a siloxane skeleton having olefinic unsaturated bonds.

[0028] The mass ratio of the content of the crosslinking aid (D) to the content of the crosslinking agent (C) is 5 or more.

[0029] <Elastomer (A)>

[0030] Elastomer (A) is not particularly limited to any fluorinated elastomer other than perfluorinated elastomers, and is also called uncured fluororubber. Examples of crosslinking types include peroxide crosslinking, polyol crosslinking, amine crosslinking, and radiation crosslinking. Among these, fluorinated elastomers that can be crosslinked by peroxides are preferred from the perspective that it does not require the use of acid absorbers that become particle generation sources in plasma atmospheres, etc., and that the resulting sealing material does not pose a risk of particle generation during use.

[0031] The elastomer (A) contained in this composition may be one type or two or more types.

[0032] In this invention, "elastomer" and "rubber" are synonymous and are not distinguished in any particular way.

[0033] As a specific example of elastomer (A), examples include fluorinated elastomers (FKM), tetrafluoroethylene-propylene elastomers (FEPM), and fluorinated thermoplastic elastomers (e.g., elastomers comprising at least one elastomeric polymer segment and at least one non-elastomeric polymer segment, wherein at least one of them is a fluorinated polymer segment).

[0034] As the elastomer (A), an elastomer that can produce a sealing material resistant to plasma (plasma etching) used in various semiconductor dry processes is preferred, and FKM, which has good plasma resistance and excellent sealing performance, is even more preferred. In addition, FKM is also preferred in terms of low cost and versatility.

[0035] As the elastomer (A), products synthesized using conventionally known methods can be used, as well as commercially available products. Examples of such commercially available products include "DAI-EL" manufactured by Daikin Industries, Ltd., "Viton" manufactured by Chemours, "Dyneon" manufactured by 3M, and "Technoflon" manufactured by Solvay.

[0036] The fluorine content of the elastomer (A) is preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 63% by mass or more, preferably 73% by mass or less, more preferably 72% by mass or less, and even more preferably 71% by mass or less.

[0037] By using elastomers (A) with fluorine content within the above range, it is possible to easily obtain sealing materials with 100% Mo content, exhibiting excellent hardness, tensile strength, and 100% Mo with a good balance.

[0038] The fluorine content can be determined by using... 19 F-NMR, 1 Fluorine elemental analysis such as H-NMR or mass spectrometry (MS) is used for determination and calculation.

[0039] The fluorine content in this invention is a value obtained by rounding to the nearest whole number.

[0040] As an example of elastomer (A), an elastomer (A1) with a fluorine content in the range of 69 to 73% by mass and an elastomer (A2) with a fluorine content in the range of 55 to 68% by mass are preferred.

[0041] If the fluorine content of elastomers (A1) and (A2) is within the above range, the types of structural units constituting these elastomers may be the same or different.

[0042] When this composition contains an elastomer (A1), the elastomer (A1) contained in this composition may be one type or two or more types. Similarly, when this composition contains an elastomer (A2), the elastomer (A2) contained in this composition may be one type or two or more types.

[0043] The fluorine content of the elastomer (A1) is 69% by mass or more, preferably 70% by mass or more, and 73% by mass or less, preferably 71% by mass or less.

[0044] The elastomer (A2) has a fluorine content of 55-68% by mass, preferably 60-68% by mass, more preferably 63-68% by mass, and even more preferably 65-68% by mass.

[0045] By using the elastomers (A1) and (A2), sealing materials exhibiting 100% Mo high hardness, particularly with excellent balance, and high tensile strength can be readily obtained. Furthermore, a homogeneous elastomer composition can be obtained in a short time, and an elastomer composition with excellent formability, especially excellent compressibility, can be readily obtained.

[0046] The Mooney viscosity of the elastomer (A) is preferably 10 or more, more preferably 15 or more, even more preferably 20 or more, preferably 140 or less, more preferably 120 or less, even more preferably 80 or less, and particularly preferably 60 or less.

[0047] If the Mooney viscosity of the elastomer (A) is within the above range, an elastomer composition with excellent formability, especially excellent compressibility, can be easily obtained.

[0048] Additionally, the Mooney viscosity in this specification refers to the Mooney viscosity (ML1+10) at 121°C as measured according to ASTM D 1646.

[0049] The content of elastomer (A) in the solid component of this composition is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 97% by mass or less, and more preferably 95% by mass or less.

[0050] If the content of elastomer (A) is within the above range, it is easy to obtain a sealing material with excellent sealing properties and plasma resistance.

[0051] In this specification, solid components refer to components other than solvents.

[0052] The content of elastomer (A1) is preferably 60% by mass or more, more preferably 65% ​​by mass or more, more preferably 95% by mass or less, and more preferably 90% by mass or less, relative to the total content of elastomer (A1) and (A2) in the composition.

[0053] If the mass ratio of the contents of elastomers (A1) and (A2) is within the above range, a uniform elastomer composition can be obtained in a short time. An elastomer composition with excellent formability, especially excellent compressibility, can be easily obtained. A sealing material with 100% Mo content, exhibiting excellent hardness, tensile strength, and 100% Mo with good balance, can be easily obtained.

[0054] [FKM]

[0055] There are no particular limitations on FKM, but examples can be given of polymers that contain hydrogen atoms (carbon-hydrogen bonds) in the polymer backbone. Specifically, it is preferred to include structural units derived from vinylidene fluoride.

[0056] There are no specific limitations on FKM. For example, we can cite polymers based on vinylidene fluoride-hexafluoropropylene, polymers based on vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, polymers based on vinylidene fluoride-propylene-tetrafluoroethylene, polymers based on ethylene-tetrafluoroethylene-perfluoroalkyl vinyl ether, and polymers based on vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether.

[0057] As a preferred example of the perfluoroalkyl vinyl ether, perfluoromethyl vinyl ether can be cited.

[0058] Among them, considering the superior plasma resistance, heat resistance, and chemical resistance, ternary polymers are preferred, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene polymers are even more preferred.

[0059] Fluorinated elastomers that can be crosslinked by peroxides preferably have functional groups such as iodine, bromine, cyano, peroxy, and unsaturated groups. From the perspective of the ease of introducing functional groups, iodine and bromine groups are more preferred.

[0060] Fluorinated elastomers 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 during the synthesis of the elastomer.

[0061] Examples of iodine- and / or bromine-containing compounds include, for example, compounds represented by formula (1) or (2).

[0062] Fluorinated elastomers having iodine and / or bromine groups on the side chains can be synthesized by using compounds represented by formula (1), and fluorinated elastomers having iodine and / or bromine groups at the ends can be synthesized by using compounds represented by formula (2).

[0063] CY 1 2 = CY 2 RfX (1)

[0064] [Y 1 and Y 2 Each of the following is independently a fluorine atom, a hydrogen atom, or a methyl group; Rf is a straight-chain or branched fluorinated alkylene group in which some or all hydrogen atoms are replaced by fluorine atoms, or a group in which a portion of the fluorinated alkylene group contains an ether bond; X is an iodine atom or a bromine atom.

[0065] As a specific example of a compound represented by the above formula (1), the compound described in International Publication No. 2009 / 119409 can be cited.

[0066] I n Br m R(2)

[0067] [R is a fluoroalkyl group with 1 to 12 carbon atoms, n and m are each independent integers from 0 to 2, and n+m is 1 or 2.]

[0068] As specific examples of compounds represented by the above formula (2), compounds described in Japanese Patent Application Publication No. 2002-97329 or Japanese Patent Application Publication No. 2008-56739 may be cited.

[0069] <Compounds containing olefinic unsaturated bonds (B)>

[0070] This composition uses a compound (B) containing olefinic unsaturated bonds, thus enabling the easy acquisition of a non-adhesive sealing material with excellent plasma resistance.

[0071] Compound (B) is at least one compound selected from compounds (B1) having a perfluorinated skeleton with olefinic unsaturated bonds and compounds (B2) having a siloxane skeleton with olefinic unsaturated bonds. From the viewpoint of readily obtaining sealing materials with superior plasma resistance, compound (B) preferably includes compound (B1).

[0072] Examples of alkenyl unsaturated bonds include, for example, vinyl, methyl vinyl, allyl, propenyl, isopropenyl, butenyl, pentenyl, hexenyl, heptenyl, and other alkenyl groups with 2 to 8 carbon atoms, as well as vinylphenyl, (meth)acryloyl, allyloxy, styryl, and propargyl. Among these, alkenyl groups are preferred, alkenyl groups with 2 to 4 carbon atoms are more preferred, and vinyl groups are particularly preferred.

[0073] Compound (B) may have two or more olefinic unsaturated bonds.

[0074] Compound (B) can be synthesized by conventionally known methods or is a commercially available product. An example of such a commercially available product is "SIFEL" (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0075] As commercially available products containing compound (B), including single-component and two-component commercially available products, any of them may be used. Furthermore, as commercially available products containing compound (B), including liquid, paste, oil, and mirable types, any of them may be used.

[0076] When a commercially available product is used as compound (B), the product may sometimes contain additives such as reactive organosilicon compounds having two or more hydrosilyl groups within their molecules (e.g., organosilicon compounds described in Japanese Patent Application Publication No. 2003-183402, Japanese Patent Application Publication No. 11-116684, etc.), catalysts (e.g., catalysts described in Japanese Patent Application Publication No. 2003-183402, Japanese Patent Application Publication No. 11-116684, etc.), and filler materials (e.g., silica). Compounds containing these additives may also be used as compound (B).

[0077] From the viewpoint that a uniform elastomer composition can be obtained in a shorter time and that a sealing material with better plasma resistance can be easily obtained, the content of compound (B) in this composition relative to 100 parts by mass of elastomer (A) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, preferably 50 parts by mass or less, more preferably 25 parts by mass or less, further preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less.

[0078] From the viewpoint that sealing materials with superior plasma resistance can be easily obtained, the mass ratio of the content of compound (B) to the content of crosslinking agent (C) in this composition (content of compound (B) / content of crosslinking agent (C)) is preferably 1 or more, more preferably 2 or more, more preferably 20 or less, and more preferably 10 or less.

[0079] [Compound (B1)]

[0080] Compound (B1) is a compound other than elastomer (A).

[0081] Examples of compounds (B1) include compounds with a perfluoropolyether structure having an olefin unsaturated bond and compounds with a perfluoroalkylene structure having an olefin unsaturated bond. Among these, compounds with a perfluoropolyether structure having an olefin unsaturated bond are preferred (hereinafter also referred to as "compound (B1-1)").

[0082] When the composition contains compound (B1), the compound (B1) contained in the composition may be one or more.

[0083] Compound (B1-1)

[0084] The compound (B1-1) is preferably a perfluoropolyether having two or more olefinic unsaturated bonds within one molecule.

[0085] Preferred examples of compound (B1-1) include the compounds described in Japanese Patent Application Publication No. 2003-183402, Japanese Patent Application Publication No. 11-116684, Japanese Patent Application Publication No. 11-116685 and Japanese Patent Application Publication No. 2015-67737.

[0086] As a compound (B1-1), examples of compounds represented by the following formula (1) can be cited.

[0087] Z 1 -(X) p -(Rf-Q) a -Rf-(X) p -Z 2 ...(1)

[0088] X can be independently -CH2-, -CH2O-, -CH2OCH2-, or *-Si(R) 2 )2-Ph-(Ph: phenylene), *-Y-NR 1 SO2- or *-Y-NR 1 -CO-(where Y is -CH2- or *-Si(R) 2 )2-Ph-, the * part is related to Z 1 or Z 2 (bonding).

[0089] Rf stands for divalent perfluoropolyether (divalent perfluorooxyolefin).

[0090] p is independently 0 or 1; a is an integer greater than or equal to 0, preferably an integer from 0 to 10, and more preferably an integer from 0 to 6.

[0091] Q is a group represented by formula (2), (3) or (4).

[0092] R 2 These are monovalent hydrocarbon groups with 1 to 10 carbon atoms, especially 1 to 8 carbon atoms, and are either substituted or unsubstituted, such as alkyl groups like methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, octyl, decyl, etc.; cycloalkyl groups like cyclopentyl, cyclohexyl, cycloheptyl, etc.; alkenyl groups like vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, etc.; aryl groups like phenyl, tolyl, xylyl, naphthyl, etc.; and aralkyl groups like benzyl, phenethyl, phenylpropyl, etc., where some or all of the hydrogen atoms of these groups are substituted by halogen atoms (e.g., fluorosubstituted alkyl groups like chloromethyl, chloropropyl, bromoethyl, 3,3,3-trifluoropropyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl).

[0093] R 1 It is a hydrogen atom or related to the above as R 2 Examples of substituted or unsubstituted monovalent hydrocarbon groups with the same number of carbons (1-10), particularly 1-8, include hydrogen atoms or groups with the same number of carbons as R. 2 The same group, such as alkyl such as methyl, ethyl, propyl, isopropyl, cyclohexyl, alkenyl such as vinyl, allyl, aryl such as phenyl, tolyl, etc., groups in which some or all of the hydrogen atoms are replaced by halogen atoms (e.g., fluorosubstituted alkyl such as chloromethyl, chloropropyl, 3,3,3-trifluoropropyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl).

[0094] Z 1 and Z 2 Each can be an independent group containing an olefinic unsaturated bond, and can be -Si (a group containing an olefinic unsaturated bond) (R')2.

[0095] The group containing the alkene unsaturated bond is preferably a monovalent alkenyl group, more preferably a monovalent alkenyl group with 2 to 4 carbon atoms, and particularly preferably a monovalent vinyl group.

[0096] R' can be a substituted or unsubstituted monovalent hydrocarbon group, specifically alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, and hexyl; aryl groups such as phenyl, tolyl, and xylyl; and haloalkyl groups such as 3-chloropropyl and 3,3,3-trifluoropropyl. Alkyl groups with 1 to 5 carbon atoms are preferred.

[0097] [Chemistry 1]

[0098]

[0099] -(X) p -CH2CH2R 4 CH2CH2-(X) p - -(3)

[0100]

[0101] In equations (2) to (4), X, p, and R 1 With X, p, R in equation (1) above 1 Same definition. R 3 and R 4 Each is independently a divalent hydrocarbon group, optionally selected from oxygen, nitrogen, silicon, and sulfur atoms, with one or more substituted or unsubstituted groups inserted in the middle of the bond, R in formula (2) 3 and R in equation (3) 4 Each can be a group represented independently by formula (5) or (6).

[0102] [Chemistry 2]

[0103]

[0104] In equations (5) and (6), R 5 For substituted or unsubstituted monovalent hydrocarbon groups, R 6 It contains one or more groups selected from carbon, oxygen, nitrogen, silicon and sulfur atoms.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] -(OR 7 ) n - It can be the same group as Rf below.

[0110] The compound represented by formula (1) above is preferably the compound represented by formula (1-1) below.

[0111] CH2=CH-(X) p -(Rf-Q) a -Rf-(X) p -CH=CH2···(1-1)

[0112] [The definitions of the symbols in equation (1-1) are the same as those in equation (1).]

[0113] 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).

[0114] CH2=CH-(X) p-Rf-(X) p -CH=CH2···(1-1-1)

[0115] [The definitions of the symbols in equation (1-1-1) are the same as those in equation (1).]

[0116] Specific examples of Rf can be cited from the following groups.

[0117] -[CF(Z)OCF2] p -(CF2) r -[CF2OCF(Z)] q -

[0118] (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)

[0119] -CF2CF2OCF2-(CF(CF3)OCF2) s -(CF2) r -(CF2OCF(CF3)) t -CF2OCF2CF2-

[0120] (r, s, and t are integers that satisfy 0 ≤ r ≤ 6, s ≥ 0, t ≥ 0, 0 ≤ s + t ≤ 200, preferably 2 ≤ s + t ≤ 110).

[0121] -CF(Z)-(OCF(Z)CF2) u -(OCF2) v -OCF(Z)-

[0122] (Z is a fluorine atom or -CF3, u and v are integers satisfying 1≤u≤100 and 1≤v≤50),

[0123] -CF2CF2-[OCF2CF2CF2] w -OCF2CF2-

[0124] (w is an integer that satisfies 1≤w≤100).

[0125] [Compound (B2)]

[0126] Compound (B2) is preferably a polysiloxane having two or more olefinic unsaturated bonds per molecule, and more preferably an organopolysiloxane having two or more olefinic unsaturated bonds per molecule and whose organic groups are bonded to silicon atoms. There are no particular limitations on the bonding positions of the olefinic unsaturated bonds.

[0127] When the composition contains compound (B2), the compound (B2) contained in the composition may be one or more.

[0128] Examples of organic groups that bond with silicon atoms include, for example, olefinic unsaturated bonds, straight-chain alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, aralkyl groups, and haloalkyl groups.

[0129] Examples of straight-chain alkyl groups include methyl, ethyl, propyl, hexyl, octyl, decyl, and other groups with 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms.

[0130] Examples of branched alkyl groups include isopropyl, isobutyl, tert-butyl, and 2-ethylhexyl groups with 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms.

[0131] Examples of cycloalkyl groups include cyclopentyl and cyclohexyl groups with 3 to 20 carbon atoms.

[0132] Examples of aryl groups include phenyl, tolyl, and other groups with 6 to 20 carbon atoms.

[0133] Examples of aralkyl groups include benzyl, 2-phenylethyl, and 2-methyl-2-phenylethyl groups with 7 to 20 carbon atoms.

[0134] Examples of haloalkyl groups include 3,3,3-trifluoropropyl, 2-(nonafluorobutyl)ethyl, 2-(heptadecylfluorooctyl)ethyl, etc., which have 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms.

[0135] The organic groups bonded to silicon atoms are preferably straight-chain alkyl, alkenyl, or aryl groups, more preferably straight-chain alkyl, alkenyl, or aryl groups having 1 to 6 carbon atoms, and particularly preferably methyl, vinyl, or phenyl groups.

[0136] There are no particular limitations on the molecular structure of compound (B2). Examples include linear, branched, partially branched linear, and dendritic structures, with linear and partially branched linear structures being preferred. Compound (B2) can be a homopolymer having these molecular structures, a copolymer having these molecular structures, or a mixture of two or more of these polymers.

[0137] Examples of compounds (B2) include dimethyl polysiloxanes whose molecular chains are capped at both ends by dimethylvinylsiloxy groups, dimethyl polysiloxanes whose molecular chains are capped at both ends by methylphenylvinylsiloxy groups, dimethyl siloxane-methylphenyl siloxane copolymers whose molecular chains are capped at both ends by dimethylvinylsiloxy groups, dimethyl siloxane-methylvinyl siloxane copolymers whose molecular chains are capped at both ends by dimethylvinylsiloxy groups, dimethyl siloxane-methylvinyl siloxane-methylphenyl siloxane copolymers whose molecular chains are capped at both ends by silanol groups, dimethyl siloxane-methylvinyl siloxane-methylphenyl siloxane copolymers whose molecular chains are capped at both ends by silanol groups, dimethyl siloxane-methylvinyl siloxane-methylphenyl siloxane copolymers whose molecular chains are capped at both ends by trimethylsiloxy groups, methyl (3,3,3-trifluoropropyl) polysiloxanes whose molecular chains are capped at both ends by dimethylvinylsiloxy groups, and polysiloxanes of the formula (CH3)3SiO 1 / 2 The siloxane unit and formula represented are: (CH3)2(CH2=CH)SiO 1 / 2 The siloxane unit and formula represented by: CH3SiO 3 / 2 The siloxane unit and formula represented by: (CH3)2SiO 2 / 2 Organosiloxane copolymers composed of siloxane units, and compounds represented by the following formula (7).

[0138] [Chemistry 3]

[0139]

[0140] In equation (7), each R 1 Each is an independent monovalent hydrocarbon group, either unsubstituted or substituted, and each R 2 Independently, it is alkyl, alkoxyalkyl, alkenyl, or acyl, b is an integer from 2 to 100, and a is an integer from 1 to 3. R in formula (7) 1 and R 2 At least two of them contain the olefinic unsaturated bonds.

[0141] In equation (7), R 1 Each group is independently unsubstituted or substituted, preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of such groups are the same as those exemplified above as organic groups bonded to silicon atoms. Among these, monovalent hydrocarbon groups having 1 to 6 carbon atoms are preferred, and alkenyl, aryl, and alkyl groups having 1 to 3 carbon atoms are more preferred.

[0142] As R in equation (7) 2 Alkyl and alkenyl groups, for example, are the same straight-chain alkyl, branched alkyl, cyclic alkyl, and alkenyl groups as those exemplified above as organic groups bonded to silicon atoms.

[0143] As R in equation (7) 2Alkoxyalkyl groups, for example, methoxyethyl, methoxypropyl, etc., are groups with 2 to 10 carbon atoms.

[0144] As R in equation (7) 2 Acyl groups, for example, are groups with 2 to 10 carbon atoms, such as acetyl and octanoyl.

[0145] In formula (7), b is preferably an integer from 10 to 50, and a is preferably 3.

[0146] <Crosslinking agent (C)>

[0147] The crosslinking agent (C) is not particularly limited and can be selected from existing known crosslinking agents depending on the type of elastomer (A) used.

[0148] The crosslinking agent (C) contained in this composition may be one type or two or more types.

[0149] As a crosslinking agent (C), for example, when using FKM, examples include peroxide crosslinking agents, polyamine crosslinking agents, polyol crosslinking agents, triazine crosslinking agents, etc.

[0150] From the viewpoint that there is no need to incorporate acid absorbers such as magnesium oxide and calcium hydroxide, which can become particle generation sources in plasma atmospheres, into the composition, and that the resulting sealing material does not pose a risk of particle generation during use, peroxide-based crosslinking agents are preferred.

[0151] Examples of peroxide-based crosslinking agents include 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, di-tert-butyl peroxide, tert-butyldicumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-(tert-butylperoxide)-3-hexyne, 2,5-dimethyl-2,5-di(benzoyl peroxide)hexane, α,α'-bis(tert-butylperoxide-m-isopropyl) α,α-bis(tert-butylperoxyisopropyl)carbonate, di(4-tert-butylcyclohexyl)peroxydicarbonate, p-chlorobenzoyl peroxide, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide, 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-butyl maleate peroxide.

[0152] Preferably, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, 2,4-dichlorobenzoyl peroxide, diisopropylbenzene peroxide, benzoyl peroxide, and α,α'-bis(tert-butylperoxide-m-isopropyl)benzene are used, and more preferably 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane are used.

[0153] From the viewpoint that a sealing material exhibiting excellent hardness, tensile strength, and 100% Mo with good balance can be easily obtained by fully carrying out the crosslinking reaction, the content of the crosslinking agent (C) in this composition is preferably 0.2 to 4 parts by mass relative to 100 parts by mass of the elastomer (A), more preferably 0.2 to 2.5 parts by mass.

[0154] <Crosslinking aid (D)>

[0155] There are no particular limitations on the crosslinking aid (D), and any existing and known crosslinking aid may be selected according to the type of crosslinking agent (C).

[0156] The crosslinking aid (D) contained in this composition may be one or more.

[0157] For example, examples of crosslinking aids (D) used when using peroxide-based crosslinking agents include: triallyl isocyanurate; triallyl cyanurate; trimethylallyl isocyanurate; triallyl formaldehyde; triallyl trimellitate; N,N'-m-phenylene bismaleimide; diacetylacetate; diallyl phthalate; tetraallyl terephthalamide; ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate and other multifunctional (meth)acrylates that can be co-crosslinked by free radicals (multifunctional monomers): higher carboxylic acid metal salts: polyol (meth)acrylates: (meth)acrylate metal salts.

[0158] Triallyl isocyanurate is preferred because it exhibits excellent reactivity and heat resistance, and can easily be used to obtain high-modulus sealing materials with high hardness.

[0159] From the viewpoint that a sealing material exhibiting excellent hardness, tensile strength, and 100% Mo with good balance can be easily obtained by fully carrying out the crosslinking reaction, the content of the crosslinking aid (D) in this composition relative to 100 parts by mass of the elastomer (A) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 4 parts by mass or more, 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.

[0160] In particular, to suppress cracking of the sealing material that may occur in a plasma atmosphere or the like, a radioactively cross-linked sealing material (radiation-treated material) is preferred. In this case, from the viewpoint that a sealing material with higher hardness and higher modulus can be easily obtained even without using the filler material described later, the content of the cross-linking aid (D) in this composition is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, more 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).

[0161] From the viewpoint that the reaction of the crosslinking agent (C) is just right, so that a sealing material exhibiting the desired physical properties can be easily obtained, and especially that a sealing material with higher hardness and higher modulus can be easily obtained even without the use of the filler material described later, the mass ratio of the content of the crosslinking aid (D) to the content of the crosslinking agent (C) in this composition (content of crosslinking aid (D) / content of crosslinking agent (C)) is 5 or more, preferably 8 or more, more preferably greater than 8, further preferably 9 or more, particularly preferably 10 or more, preferably 30 or less, and more preferably 20 or less.

[0162] <Other Ingredients>

[0163] In addition to (A) to (D) described above, this composition may, without impairing the effects of the present invention, contain other conventionally known components incorporated into the sealing material as needed. Examples of such other components include: reactive organosilicon compounds having two or more silane groups within their molecules; catalysts; acid scavengers such as magnesium oxide and calcium hydroxide; anthraquinone pigments, perylene pigments, and dioxin pigments. Organic pigments such as azinoid pigments; plasticizers; processing aids; vulcanization accelerators; anti-aging agents; antioxidants; inorganic fillers; organic fillers.

[0164] The other ingredients may be used in single or multiple forms.

[0165] Examples of the reactive organosilicon compounds include compounds similar to those described in Japanese Patent Application Publication No. 2003-183402 and Japanese Patent Application Publication No. 11-116684.

[0166] As the catalyst, examples preferably include catalysts similar to those described in Japanese Patent Application Publication No. 2003-183402 and Japanese Patent Application Publication No. Hei 11-116684.

[0167] As the organic pigment, examples preferably include organic pigments that are the same as those described in International Patent Publication No. 2016 / 043100, Japanese Patent No. 4720501, and International Patent Publication No. 2004 / 094527.

[0168] The inorganic and organic fillers (hereinafter collectively referred to as "fillers") are granular (powder) components other than the compound (B), crosslinking agent (C), and crosslinking aid (D).

[0169] Examples of inorganic filler materials include carbon black, silicon dioxide, barium sulfate, titanium dioxide, and aluminum oxide.

[0170] Examples of organic filler materials include fluoropolymers such as PTFE, PFA, FEP, ETFE, and PVDF, polyethylene resins, polyimide resins, silicone resins, and melamine resins.

[0171] When this composition is used to manufacture a sealing material in which particle generation becomes a problem in plasma atmospheres, the content of the filler material relative to 100 parts by mass of elastomer (A) is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and most preferably 0 parts by mass.

[0172] <Method for manufacturing this composition>

[0173] This composition can be manufactured by mixing (kneading) the elastomer (A), compound (B), crosslinking agent (C) and crosslinking aid (D), as well as other components as needed.

[0174] The mixing order of the elastomer (A), compound (B), crosslinking agent (C), crosslinking aid (D), and other components is not particularly limited. They can be mixed (kneaded) in any order or all at once. It is preferred to mix (knead) them sequentially to make the components uniform.

[0175] The mixing (kneading) process can use conventionally known mixing (kneading) machines, such as open roller presses, Banbury mixers, twin-spindle roller presses, and kneaders.

[0176] In addition, during the mixing (kneading) process, depending on the type of mixing (kneading) machine, mixing (kneading) can be carried out under heating or cooling conditions as needed.

[0177] Sealing Materials

[0178] The sealing material of one embodiment of the present invention (hereinafter also referred to as "the sealing material") is a sealing material obtained from the present composition, preferably a crosslinked body of the present composition, and more preferably a radiation crosslinked body of the present composition.

[0179] The radiation crosslinker of this composition can be specifically exemplified by the composition itself, or by a method comprising irradiating a crosslinker of the composition (e.g., a crosslinker obtained by thermally crosslinking the composition) with radiation.

[0180] This sealing material is obtained from the aforementioned composition, and therefore exhibits excellent hardness, tensile strength and 100% Mo with a good balance, as well as excellent plasma resistance (free radical resistance), crack resistance, and compression set resistance.

[0181] This sealing material can be used, for example, as gaskets or seals for various components. In particular, due to the aforementioned effects, it is suitable for use in semiconductor manufacturing equipment and plasma processing equipment, and is especially suitable for drive units, such as gate valves used in the openings of plasma processing chamber units.

[0182] The shape and other properties of this sealing material can be appropriately selected according to the intended use.

[0183] This sealing material may be a sealing material that does not contain the aforementioned filler material but has the following physical properties.

[0184] The 100% Mo content of this sealing material, as determined according to JIS K 6251:2017, is preferably 2.4 MPa or more, more preferably 3 MPa or more, even more preferably 4.5 MPa or more, and particularly preferably 5 MPa or more.

[0185] The Shore A hardness (type A hardness tester hardness) of this sealing material, as measured according to JIS K 6253:2012, is preferably 60 or higher.

[0186] The tensile strength of this sealing material, as determined by JIS K 6251:2017, is preferably 10 MPa or higher.

[0187] <Manufacturing method of this sealing material>

[0188] Specifically, this sealing material can be manufactured by molding the composition. From the viewpoint that sealing materials with superior plasma resistance (free radical resistance), crack resistance, and non-adhesiveness can be easily obtained, a cross-linked product obtained by a method including a cross-linking process (cross-linking process) of the composition is preferred. Furthermore, from the viewpoint that sealing materials exhibiting excellent hardness, tensile strength, elongation at break, and 100% Mo with good balance can be easily obtained, a radiation-treated product obtained by a method including a process of irradiating the composition with radiation (radiation irradiation process) is more preferred.

[0189] When forming a sealing material from this composition, a tableting process is preferred from the viewpoint of improving the efficiency of the forming operation and reducing the defect rate. This tableting process is usually carried out using rollers or the like, and is typically a process in which the composition is pre-formed into a sheet shape.

[0190] The sheet obtained by the pressing process is preferably pre-formed into the desired sealing material shape before the crosslinking process and the radiation irradiation process.

[0191] In this preforming process, the sheet obtained in the tableting process can be directly formed into the desired sealing material shape, or the sheet obtained in the tableting process can be formed into a rope shape (the same meaning applies to strips, noodles, etc.) by cutting or extrusion molding, and then the resulting rope shape can be formed into the desired sealing material shape.

[0192] When manufacturing this sealing material, it is preferable to include a crosslinking process before the radiation irradiation process, and more preferably, the crosslinking process includes a primary crosslinking process and a secondary crosslinking process.

[0193] The crosslinking process is preferably performed using the desired sealing material shape obtained through the preforming.

[0194] The preferred cross-linking process is a process of heating and pressurizing the desired sealing material shape obtained by the preforming. Specifically, examples include placing the preformed material into a mold and using a hot press or similar device to perform a cross-linking process at a pressure of about 2 to 15 MPa and a temperature of, for example, 150 to 200°C for about 5 to 20 minutes.

[0195] The secondary crosslinking process is preferably a process of heating the molded body obtained in the primary crosslinking process. Specifically, examples include heating at a temperature of 150 to 300°C for 1 to 24 hours, preferably 3 to 24 hours, using various ovens under normal to reduced pressure, preferably using a vacuum oven.

[0196] This secondary crosslinking process promotes crosslinking, and even if unreacted components remain after the primary crosslinking process, these unreacted components can be decomposed and volatilized, resulting in a sealing material that releases less gas.

[0197] The radiation used in the radiation irradiation process is not particularly limited as long as it can crosslink the elastomer (A). Examples include X-rays, gamma rays, electron beams, proton beams, neutron beams, heavy particle beams, alpha rays, and beta rays, with gamma rays and electron beams being preferred.

[0198] The radiation used for irradiation can be a single type or two or more types.

[0199] When irradiating with radiation, it is preferable to irradiate with an absorption dose of 1 to 120 kGy, more preferably 20 to 100 kGy. By irradiating with this amount of radiation, unreacted components that may become particles or release gases can be reduced, and sealing materials with excellent plasma resistance and crack resistance can be easily obtained while preventing the molecular weight of the elastomer (A) from being too low.

[0200] The radiation irradiation process can be carried out in two or more stages by changing the conditions.

[0201] While irradiation can occur in air, the presence of oxygen during the process hinders the cross-linking reaction, reduces the mechanical strength of the sealing material, and may cause the surface of the sealing material to become sticky. Therefore, the irradiation process is preferably carried out in an inert gas atmosphere such as nitrogen or argon.

[0202] Example

[0203] The present invention will now be described in more detail with reference to embodiments, but the invention is not limited thereto.

[0204] [Example 1]

[0205] 70 parts by weight of Tecnoflon P959 (manufactured by Solvay), 30 parts by weight of Tecnoflon P757 (manufactured by Solvay), 1.0 part by weight of SIFEL 8070A (manufactured by Shin-Etsu Chemical Co., Ltd.), 1.0 part by weight of SIFEL 8070B (manufactured by Shin-Etsu Chemical Co., Ltd.), 4.0 parts by weight of TAIC (manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate), and 0.5 parts by weight of Perhexa25B (manufactured by Nippon Oil Co., Ltd.) were sequentially added to a kneader and mixed until the current value stabilized, thereby obtaining a block-shaped elastomer composition.

[0206] At least one of SIFEL 8070A and SIFEL 8070B comprises a compound having a perfluorinated skeleton with olefinic unsaturated bonds.

[0207] The obtained block-shaped elastomer composition was placed into a mold and pressurized at 170°C for 10 minutes under a pressure of 5 MPa using a compression vacuum press (first crosslinking). The pressurized sheet was then placed in a vacuum oven (vacuum degree: 50 Pa) and heated at 200°C for 16 hours under reduced pressure (second crosslinking). The second crosslinked sheet was then irradiated with radiation at an absorption linearity of 80 kGy to obtain a radiation crosslinked body.

[0208] The following routine physical properties and plasma resistance of the obtained radiation crosslinkers were determined. The results are shown in Table 1.

[0209] [Examples 2-10 and Comparative Examples 1-2]

[0210] Except that the components shown in Table 1 were used in the amounts shown in Table 1, the following conventional physical properties and plasma resistance were measured in the same manner as in Example 1. The results are shown in Table 1.

[0211] <Common Physical Properties>

[0212] As standard physical properties, Shore A hardness was determined according to JIS K 6253:2012, and tensile strength and tensile stress at 100% elongation (100% Mo) were determined according to JIS K6251:2017.

[0213] Plasma Resistance

[0214] The plasma resistance (mass reduction rate) of the obtained molded body was measured. The specific measurements are as follows.

[0215] Using a flat plasma processing device with an electrode diameter of φ300mm and an electrode spacing of 50mm, the obtained shaped body was irradiated with plasma for 3 hours under the conditions of RF1000W, O2 gas and CF4 gas flow ratio (O2:CF4) 190:10, gas flow rate 200sccm, and vacuum degree 1torr.

[0216] The resulting molded body was placed 6 cm from the plasma electrode. Next, the mass of the molded body before and after the test was measured, and the mass reduction rate (%) was calculated using the following formula to evaluate plasma resistance. It can be said that the smaller the mass reduction rate, the better the plasma resistance.

[0217] Mass reduction rate (%) = [(mass of molded part before test - mass of molded part after test) / mass of molded part before test] × 100

[0218] [Table 1]

[0219]

[0220] The raw materials in Table 1 that were not used in Example 1 are as follows.

[0221] Tecnoflon P459: Crosslinked fluorinated elastomer (manufactured by Solvay).

[0222] • DAI-EL G912: Crosslinked fluorinated elastomer (manufactured by Daikin Industries, Ltd.)

[0223] • SIFEL 3590-N (manufactured by Shin-Etsu Chemical Industry Co., Ltd., containing compounds with a perfluorinated skeleton having olefinic unsaturated bonds, single-component liquid type)

[0224] X-71-906 (manufactured by Shin-Etsu Chemical Industry Co., Ltd., a compound containing a perfluorinated skeleton with olefinic unsaturated bonds, wear-resistant)

[0225] • KE-1830 (manufactured by Shin-Etsu Chemical Industry Co., Ltd., a compound containing a siloxane skeleton with olefinic unsaturated bonds, single-liquid type).

Claims

1. An elastomer composition comprising a crosslinked fluorinated elastomer (A) other than a perfluorinated elastomer, a compound containing an olefinic unsaturated bond (B), a crosslinking agent (C), and a crosslinking aid (D), The crosslinked fluorinated elastomer (A) comprises an elastomer (A1) with a fluorine content ranging from 69% to 73% by mass and an elastomer (A2) with a fluorine content ranging from 55% to 68% by mass, wherein the content of the elastomer (A1) is 60% to 95% by mass relative to the total content of the elastomers (A1) and (A2). The crosslinked fluorinated elastomer (A) comprises at least one selected from 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. The compound (B) containing olefinic unsaturated bonds comprises at least one selected from compounds with a perfluorinated skeleton having two or more olefinic unsaturated bonds within one molecule and compounds with a siloxane skeleton having two or more olefinic unsaturated bonds within one molecule. For every 100 parts by mass of the crosslinked fluorinated elastomer (A), the content of the compound (B) containing olefinic unsaturated bonds is between 0.5 and 25 parts by mass. For every 100 parts by weight of the crosslinked fluorinated elastomer (A), the content of the crosslinking agent (C) is 0.2 to 4 parts by weight. The mass ratio of the crosslinking aid (D) to the crosslinking agent (C) is 5 to 30. The crosslinking aid (D) comprises at least one selected from the following: triallyl isocyanurate, triallyl cyanurate, trimethylallyl isocyanurate, triallyl formaldehyde, triallyl trimellitate, N,N'-m-phenylene bismaleimide, diacetylacetate, diallyl phthalate, tetraallyl terephthalamide, ethylene glycol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate.

2. The elastomer composition of claim 1, wherein, The fluorinated elastomer (A) is a peroxide-crosslinkable fluorinated elastomer.

3. The elastomer composition according to claim 1 or 2, wherein, The content of the crosslinking aid (D) is 1 to 10 parts by mass relative to the content of the elastomer (A) of 100 parts by mass.

4. The elastomer composition according to any one of claims 1 to 3, wherein, The content of filler material is less than 5 parts by mass relative to 100 parts by mass of the fluorinated elastomer (A).

5. A sealing material, which is a radiocrosslinker of the elastomeric composition according to any one of claims 1 to 4.

6. A method for manufacturing sealing materials, wherein, A process comprising irradiating the elastomer composition or crosslinked product of any one of claims 1 to 4 with radiation.

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