Fluororubber composition and rubber molded article formed using the same

Abstract

The fluoro-rubber composition contains an A component, a B component, and a C component, the A component is a base rubber containing a hydrogen-containing fluoro-rubber as a main component, the B component is a compound having a perfluoropolyether skeleton, and the C component is a compound having a volume density of 0.4 g / cm 3 The following powder filler. A part or all of the B component contains an alkenyl group in the molecule. When the density of the B component is set as d B , the content of the B component with respect to 100 parts by mass of the A component is set as p B , the volume density of the C component is set as d C , the content of the C component with respect to 100 parts by mass of the A component is set as p C , (p C / d C ) / (p B / d B ) ≥ 4.

Description

TECHNICAL FIELD

[0001] The present application relates to a fluororubber composition and a rubber molded article formed using the same. BACKGROUND

[0002] A seal formed from a fluororubber composition is widely used as a seal for a semiconductor manufacturing apparatus. Patent Document 1 discloses that a fluororubber composition forming a seal contains a compound having a perfluoropolyether skeleton in order to improve plasma resistance.

[0003] Patent Document 1: Japanese Patent Publication No. 4675907 SUMMARY

[0004] The present application is a fluororubber composition containing an A component, a B component, and a C component, the A component being a base rubber containing a hydrogen-containing fluororubber as a main component, the B component being a compound having a perfluoropolyether skeleton, and the C component being a powder filler having a volume density of 0.4 g / cm 3 and a part or all of the B component contains an alkenyl group in a molecule, and when the density of the B component is set as d B , the content of the B component with respect to 100 parts by mass of the A component is set as p B , the volume density of the C component is set as d C , and the content of the C component with respect to 100 parts by mass of the A component is set as p C , (p C / d C ) / (p B / d B ) is 4 or more.

[0005] The present application is a rubber molded article formed by cross-linking the fluororubber composition of the present application.

[0006] The present application is a rubber molded article formed by cross-linking a fluororubber composition containing an A component, a B component, and a C component, the A component being a base rubber containing a hydrogen-containing fluororubber as a main component, the B component being a compound having a perfluoropolyether skeleton, and the C component being a powder filler having a volume density of 0.4 g / cm 3 and a part or all of the B component contains an alkenyl group in a molecule, and the ratio of the content of the C component with respect to the content of the B component is greater than 0.1, and the C-F bond concentration of the surface of the molded article is higher than the C-F bond concentration of the inside of the molded article.

[0007] This invention relates to a rubber molded article formed by crosslinking a fluororubber composition, wherein the fluororubber composition contains components A, B, and C. Component A is a base rubber containing hydrogen-containing fluororubber as the main component, component B is a compound having a perfluoropolyether backbone, and component C is a compound with a bulk density of 0.4 g / cm³. 3 The following powder filler, wherein part or all of component B contains an alkenyl group within the molecule, and the content of component C relative to the content of component B is greater than 0.1, wherein the peak area of ​​the C1s peak from the CH bond at 282–288 eV, measured by X-ray photoelectron spectroscopy, is defined as A. CH The peak area of ​​288–296 eV from the CF bond is set as A. CF When (A) the surface of the molded article is irradiated with X-rays CF / A CH ) / (A when X-rays are irradiated at the position farthest from the surface of the molded article in the cross-section of the molded article) CF / A CH )≥2. Detailed Implementation

[0008] The implementation method will now be described in detail.

[0009] The fluororubber composition involved in the embodiments contains component A, component B, and component C.

[0010] Component A is the base rubber. Component A, as the base rubber, contains hydrogen-containing fluororubber as its main component. Here, "hydrogen-containing fluororubber" in this application refers to fluororubber containing carbon with hydrogen bonded to the main chain of the polymer. The content of hydrogen-containing fluororubber in component A is more than 50% by mass, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass. It should be noted that component A may also contain fluororubber other than hydrogen-containing fluororubber.

[0011] Examples of hydrogen-containing fluororubbers include: polymers of vinylidene fluoride (VDF) (PVDF), copolymers of vinylidene fluoride (VDF) and hexafluoropropylene (HFP), copolymers of vinylidene fluoride (VDF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE), copolymers of tetrafluoroethylene (TFE) and propylene (Pr) (FEP), copolymers of vinylidene fluoride (VDF), propylene (Pr), and tetrafluoroethylene (TFE), copolymers of ethylene (E) and tetrafluoroethylene (TFE) (ETFE), copolymers of ethylene (E), tetrafluoroethylene (TFE), and perfluoromethyl vinyl ether (PMVE), copolymers of vinylidene fluoride (VDF), tetrafluoroethylene (TFE), and perfluoromethyl vinyl ether (PMVE), and copolymers of vinylidene fluoride (VDF) and perfluoromethyl vinyl ether (PMVE), etc. Component A preferably contains one or more of these as hydrogen-containing fluororubber, and more preferably contains vinylidene fluoride-based fluororubber (FKM) with vinylidene fluoride as the main component, such as copolymers of vinylidene fluoride (VDF) and hexafluoropropylene (HFP), copolymers of vinylidene fluoride (VDF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE).

[0012] Component B is a compound having a perfluoropolyether backbone. The compound having a perfluoropolyether backbone, which is component B, is a liquid material uniformly mixed with component A. Part or all of component B contains an alkenyl group within its molecule. Examples of alkenyl groups include: vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, etc. The vinyl group is preferred. The number of alkenyl groups within the molecule is preferably multiple. In this case, the multiple alkenyl groups within the molecule can be the same or different, whichever is acceptable.

[0013] Component B can include both compounds containing an alkenyl group within the molecule and compounds not containing an alkenyl group within the molecule. The proportion of compounds containing an alkenyl group within the molecule in component B is preferably 20% by mass or more, more preferably 30% by mass or more.

[0014] As will be described later, from the viewpoint of maintaining excellent plasma resistance in rubber molded articles formed using the fluororubber composition involved in the embodiments and suppressing the exudation of component B from the rubber molded articles, the density d of component B is... B The preferred value is 1.5 g / cm³ 3 The above, and more preferably 1.8 g / cm 3 Based on the same viewpoint, the preferred value is 2.5 g / cm³. 3 The following, or more preferably, is 2.0 g / cm³. 3 Below. When component B contains multiple compounds, the density d of component B is... BIt is the sum of the products of the densities of various compounds and their content fractions. The density d of component B, which contains an alkenyl group within the molecule. B It was obtained by measuring the gas specific gravity bottle method as specified in JIS Z8837:2018. The density d of component B, which does not contain an alkenyl group within the molecule. B It was obtained by measuring at 20°C using the vibration-type density meter method specified in JIS K0061:2001.

[0015] From the perspective of obtaining high plasma resistance of rubber molded articles, the content p of component B relative to 100 parts by mass of component A is... B Preferably, it is 0.1 parts by weight or more, more preferably 1.0 parts by weight or more. From the viewpoint of maintaining excellent plasma resistance of the rubber molded article and suppressing the exudation of component B from the rubber molded article, it is preferably 20 parts by weight or less, more preferably 15 parts by weight or less. When component B contains multiple compounds, the content p of component B... B It is the sum of the contents of various compounds.

[0016] Commercially available materials containing an alkenyl group and having a perfluoropolyether backbone as component B include, for example, SIFEL manufactured by Shin-Etsu Chemical Co., Ltd., with the SIFEL3000 series being particularly preferred. Compounds containing an alkenyl group and having a perfluoropolyether backbone are preferably liquid-type materials.

[0017] Commercially available materials that are compounds with a perfluoropolyether backbone that do not contain alkenes in the molecule and are found as component B include, for example, Fomblin Y lubricant manufactured by SOLVAY Company and GPLOil from the Krytox series manufactured by Chemours Company.

[0018] Component C is the bulk density d dispersed in component A. C 0.4 g / cm 3 The following are examples of powder fillers. Examples of powder fillers as component C include: for example, silica, resin powder, silicon carbide, boron carbide, silicon nitride, boron nitride, etc. Component C preferably contains one or more of these, and more preferably contains silica and / or resin powder. Silica can be dry silica or wet silica, either type is acceptable. Silica can be untreated hydrophilic silica or surface-modified hydrophobic silica, such as dimethyldichlorosilane, either type is acceptable. Examples of resin powders include: for example, phenolic resin powder, fluoropolymer powder, polyetheretherketone (PEEK) resin powder, etc.

[0019] From the viewpoint of maintaining excellent plasma resistance in rubber molded articles and suppressing the exudation of component B from the rubber molded articles, the bulk density d of the powder filler as component C is... C Preferably 0.01 g / cm 3 The above, more preferably 0.03 g / cm³ 3 Based on the same viewpoint, the preferred value is 0.35 g / cm³. 3 The following is more preferably 0.20 g / cm³. 3 The following describes the bulk density d of component C when it contains various powder fillers. C It is the sum of the products of the bulk density and the content fraction of various powder fillers. The bulk density d of component C. C It was obtained by measuring the tapped bulk density according to the measurement method specified in JIS R1628-1997.

[0020] From the viewpoint of maintaining excellent plasma resistance in rubber molded articles and inhibiting the exudation of component B from the rubber molded articles, the content of component C relative to 100 parts by mass of component A is p C Preferably, it is 0.1 parts by weight or more, more preferably 1.0 parts by weight or more. From the viewpoint of suppressing the precipitation of powder fillers from the rubber molded product, it is preferably 30 parts by weight or less, more preferably 20 parts by weight or less. When component C contains various powder fillers, the content p of component C... C It is the sum of the contents of various powder fillers.

[0021] From the perspective of inhibiting the precipitation of powder fillers from rubber molded articles and inhibiting the exudation of component B from rubber molded articles, the content of component C, p C The preferred content is more than that of component B. B From the same perspective, the content of component C, p C The content of component B p B The ratio (p) C / p B Preferably, it is greater than 0.1 and less than 30, more preferably greater than 0.12 and less than 25, and even more preferably greater than 1.0 and less than 20.

[0022] Commercially available materials for component C include, for example, silica such as the AEROSIL and CARPLEX series manufactured by Evonik Company; phenolic resin powders such as the BellPearl series manufactured by Air WaterBellPearl Company; fluoropolymer powders such as the KYNAR series manufactured by Arkema Company; and polyetheretherketone (PEEK) resin powders such as the VESTAKEEP series manufactured by Daicel-Evonik Company.

[0023] In the fluororubber composition involved in the embodiments, it is preferred that (p C / d C ) / (p B / d B )≥4. This means that the volume of component C is more than four times the volume of component B. From the viewpoint of maintaining excellent plasma resistance of the rubber molded article and suppressing the exudation of component B from the rubber molded article, it is more preferable to have (p C / d C ) / (p B / d B )≥10, further preferably (p C / d C ) / (p B / d B ≥50.

[0024] The fluororubber composition described in the embodiments may further contain a crosslinking agent. Examples of crosslinking agents include, for example, organic peroxides, polyols, polyamines, triazines, etc. Organic peroxides are preferred among these crosslinking agents.

[0025] Examples of organic peroxides include, for instance, 1,1-bis(tert-butylperoxide)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-tert-butylperoxide, tert-butylcumylperoxide, dicumylperoxide, α,α-bis(tert-butylperoxide)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxide)-hexyn-3, benzoyl peroxide, tert-butylperoxidebenzene, tert-butylperoxidemaleic acid, t-butylperoxyisopropyl carbonate, and t-butylperoxybenzoate. The crosslinking agent preferably contains one or more of these, and more preferably contains 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane.

[0026] The content of the crosslinking agent relative to 100 parts by mass of component A is preferably 0.5 parts by mass or more and 2.5 parts by mass or less, more preferably 0.5 parts by mass or more and 2.0 parts by mass or less.

[0027] The fluororubber composition according to this embodiment may further contain a crosslinking aid. Examples of crosslinking aids include: for instance, triallyl cyanurate, trimethallyl isocyanurate, triallyl isocyanurate, triacrylformal, triallyltrimellitate, N,N'-m-phenylene bismaleimide, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalateamide, and triallyl phosphate. Phosphate, bismaleimide, fluorinated isocyanurate triallyl ester (1,3,5-tris(2,3,3-trifluoro-2-propenyl)-1,3,5-triazine-2,4,6-trione), tris(diallylamine)-S-triazine, triallyl phosphite, N,N-diallylacrylamide, 1,6-divinyldodecylfluorohexane, hexaallyl phosphoramide, N,N,N',N'-tetraallyl phthalamide, N,N,N',N'-tetraallyl malonamide, trivinyl isocyanurate, 2,4,6-trivinylmethyltrisiloxane, tris(5-norbornene-2-methylene)cyanurate, triallyl phosphite, etc. The crosslinking aid preferably contains one or more of these, and more preferably contains triallyl isocyanurate.

[0028] The crosslinking aid is preferably 1 part or more and 10 parts or less of component A per 100 parts by mass, more preferably 2 parts or more and 5 parts or less of component A.

[0029] If the fluororubber composition according to the above-described embodiment is crosslinked, it becomes a crosslinked rubber and forms a rubber molded article. Through the action of the crosslinking agent caused by heating and the action of radiation, the crosslinking of the fluororubber composition according to the embodiment forms an intermolecular crosslinked structure of component A. Furthermore, component B, which contains an alkenyl group within its molecule, and the crosslinking aid react with component A to form an intermolecular crosslinked structure between components A.

[0030] In the rubber molded article formed by crosslinking the fluororubber composition involved in the embodiments, since a compound with a perfluoropolyether backbone as component B is used, excellent plasma resistance can be maintained. Specifically, even when irradiated with plasma, the reduction in mass can be reduced.

[0031] However, when the fluororubber composition forming the seal contains a compound with a perfluoropolyether backbone, there is a problem that the compound with the perfluoropolyether backbone leaks out of the seal.

[0032] However, in the rubber molded article formed by crosslinking the fluororubber composition according to the embodiments, the exudation of the compound having a perfluoropolyether backbone as component B can be suppressed. This is presumably because a powder filler as component C is used, and the volume of component C is much larger than that of component B, thus component B is supported by component C and retained within component A. Furthermore, by reducing the bulk density of the powder filler as component C to as low as 0.4 g / cm³... 3 Even when irradiated with plasma, the particle precipitation of powder filler, which is a C component, can be suppressed.

[0033] Furthermore, in the rubber molded article formed by crosslinking the fluororubber composition according to the embodiments, during its molding process, since the fluororubber composition contains powder filler as component C, its viscosity is high. Therefore, the flow of the compound with a perfluoropolyether backbone as component B becomes easy. As a result, component B segregates at the surface, and the CF bond concentration on the surface of the molded article is higher than the CF bond concentration inside the molded article. As a result, there are fewer CH bonds on the surface of the molded article that become the starting point of deterioration due to plasma attack, thereby improving plasma resistance. Quantitatively speaking, let A be the peak area of ​​282-288 eV from CH bonds in the C1s peak measured by X-ray photoelectron spectroscopy when irradiated with X-rays. CH The peak area of ​​288–296 eV from the CF bond is set as A. CF When, preferably (A when the surface of the molded article is irradiated with X-rays) CF / A CH ) / (A when X-rays are irradiated at the position farthest from the surface of the molded article in the cross-section of the molded article) CF / A CH≥2. From the viewpoint of maintaining excellent plasma resistance of rubber molded articles and suppressing the exudation of component B from rubber molded articles, this ratio is preferably 2.5 or higher.

[0034] There are no particular limitations on the rubber molded articles formed by crosslinking the fluororubber compositions involved in the embodiments, but they are preferably seals, and more preferably seals for semiconductor manufacturing apparatuses.

[0035] For the crosslinked rubber formed by the fluororubber composition involved in the embodiments, the hardness measured by a type A hardness tester according to JIS K6253-3:2012 is preferably 50A or more, more preferably 55A or more, and preferably 95A or less, more preferably 90A or less.

[0036] For the crosslinked rubber formed by crosslinking the fluororubber composition involved in the embodiments, the tensile strength at cut, measured using a dumbbell-shaped No. 3 test piece with a thickness of 2 mm at standard test temperature according to JIS K6251:2017, is preferably 5.0 MPa or more, more preferably 10.0 MPa or more. The elongation at cut is preferably 50% or more, more preferably 100% or more. The tensile stress at 100% elongation is preferably 1.0 MPa or more, more preferably 1.5 MPa or more.

[0037] For the crosslinked rubber formed by the fluororubber composition involved in the embodiments, the compression set measured according to JIS K6262:2013 at a test time of 72 hours and a test temperature of (200±2)°C is preferably 80% or less, more preferably 50% or less.

[0038] Example

[0039] (Seals)

[0040] Sealing components for Examples 1 to 13 and Comparative Examples 1 to 7 were prepared. The composition of each sealing component is shown in Tables 1 and 2. It should be noted that, in the case of compounds containing alkenyl groups, the density of the compound having a perfluoropolyether backbone was measured using the gas pyrometer method specified in JIS Z8837:2018; in the case of compounds not containing alkenyl groups, the density of the compound having a perfluoropolyether backbone was measured at 20°C using the vibration-type densitometer method specified in JIS K0061:2001. The bulk density of the powder filler was measured according to the tapped bulk density measurement method specified in JIS R1628-1997.

[0041] <Example 1>

[0042] A hydrogen-containing fluororubber (DAI-ELG912, manufactured by Daikin Industries, Ltd.) composed of a copolymer of vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene is used as component A. Relative to 100 parts by mass of component A, 1 part by mass (p) is added. B The B component of the compound is a liquid material containing an alkenyl group within its molecule and possessing a perfluoropolyether backbone. (SIFEL3000 series X-71-359, manufactured by Shin-Etsu Chemical Co., Ltd., density d) B 1.85g / cm 3 ), 10 parts by weight (p C The powder filler, which is the untreated hydrophilic dry silica 1 (AEROSIL 200, manufactured by Evonik Company, with a bulk density of d), is used as the C component. C 0.05g / cm 3 A fluororubber composition was prepared by mixing 1.5 parts by weight of an organic peroxide, namely 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane (PERHEXA 25B, manufactured by NOF CORPORATION), as a crosslinking agent, and 4 parts by weight of a crosslinking aid, namely triallyl isocyanurate (TAIC, manufactured by Nihon Kasei Co., Ltd.), using an open roll mill. A seal (AS-214 O-ring) was then fabricated by crosslinking this fluororubber composition. The crosslinking of the fluororubber composition was performed by a primary crosslinking process of pressing at 160°C for 10 minutes and a secondary crosslinking process of maintaining the seal in a Geer oven at 200°C for 4 hours. The resulting seal is designated as Example 1.

[0043] <Example 2>

[0044] Relative to 100 parts by weight of component A, 0.2 parts by weight (p) are added. C Hydrophobic dry silica 2 (AEROSIL R972, manufactured by Evonik Company, with a bulk density of d) surface-treated with dimethyldichlorosilane C 0.05g / cm 3 The powder filler used as component C was used to prepare a fluororubber composition, and a seal was made in the same manner as in Example 1. The resulting seal is designated as Example 2.

[0045] <Example 3>

[0046] A fluororubber composition was prepared by using dry silica 2, which was used in Example 2, as a powder filler for component C. Otherwise, a seal was fabricated in the same manner as in Example 1. The resulting seal is designated as Example 3.

[0047] <Example 4>

[0048] Combined with wet silica (CARPLEX#80, manufactured by Evonik Company, bulk density d) C 0.15g / cm 3 The powder filler used as component C was used to prepare a fluororubber composition, and a seal was made in the same manner as in Example 1. The resulting seal is designated as Example 4.

[0049] <Example 5>

[0050] Relative to 100 parts by mass of component A, as component B, 1 part by mass of a liquid material, namely compound 1 (Fomblin Y lubricant, manufactured by SOLVAY Company, density: 1.91 g / cm³), which is a perfluoropolyether backbone without alkenyl groups in its molecular structure, is further incorporated. 3 A fluororubber composition was prepared, and a seal was fabricated in the same manner as in Example 3. The resulting seal is designated as Example 5. It should be noted that the density d of component B... B It is 1.88 g / cm 3 .

[0051] <Example 6>

[0052] A fluororubber composition was prepared by combining 100 parts by mass of component A with 5 parts by mass of component B, namely compound 1, which contains an alkenyl group and has a perfluoropolyether backbone. Otherwise, a seal was fabricated in the same manner as in Example 3. The resulting seal is designated as Example 6.

[0053] <Example 7>

[0054] Relative to 100 parts by mass of component A, as component B, 1 part by mass of compound 2 (Krytox GPLOil 107, manufactured by Chemours Company, density: 1.90 g / cm³) with a perfluoropolyether backbone that does not contain alkenes within the molecule is further incorporated. 3 A fluororubber composition was prepared, and a seal was fabricated in the same manner as in Example 3. The resulting seal is designated as Example 7. It should be noted that the density d of component B... B It is 1.88 g / cm 3 .

[0055] <Example 8>

[0056] A fluororubber composition was prepared by combining 100 parts by mass of component A with 5 parts by mass of liquid material of component B, namely compound 1, which has a perfluoropolyether backbone and does not contain alkenyl groups in its molecular structure. Otherwise, a seal was fabricated in the same manner as in Example 5. The resulting seal is designated as Example 8. It should be noted that the density d of component B... B 1.90 g / cm 3 .

[0057] <Example 9>

[0058] A fluororubber composition was prepared by combining 1 part by mass of a mixed material (SIFEL3000 series X-71-369-N, manufactured by Shin-Etsu Chemical Co., Ltd.) with 100 parts by mass of component A. Seals were then manufactured in the same manner as in Example 1. The mixed material was a liquid-like material of component B, namely compound 2 (d) containing an alkenyl group within its molecule and having a perfluoropolyether backbone. B 1.90 g / cm 3 ) and silicon dioxide (d) as a C component C 0.05g / cm 3 The mixture was prepared by mixing component B and component C in a mass ratio of 89:11. The resulting seal is designated as Example 9.

[0059] <Example 10>

[0060] Combined with phenolic resin powder 1 (BellPearl R100, manufactured by Air Water BellPearl Company, bulk density d) C 0.35g / cm 3 The powder filler used as component C was used to prepare a fluororubber composition, and a seal was made in the same manner as in Example 1. The resulting seal is designated as Example 10.

[0061] <Example 11>

[0062] Combined with phenolic resin powder 2 (BellPearl R200, manufactured by Air Water BellPearl Company, bulk density d) C 0.38g / cm 3 The powder filler used as component C was used to prepare a fluororubber composition, and a seal was made in the same manner as in Example 1. The resulting seal is designated as Example 11.

[0063] <Example 12>

[0064] Combined with fluoropolymer (PVDF) powder (KYNAR MG15, manufactured by Arkema Company, bulk density d) C 0.32g / cm 3 The powder filler used as component C was used to prepare a fluororubber composition, and a seal was made in the same manner as in Example 1. The resulting seal is designated as Example 12.

[0065] <Example 13>

[0066] Combined with polyetheretherketone (PEEK) resin powder (VESTAKEEP 2000UFP10, manufactured by Daicel-Evonik Company, bulk density d) C 0.25g / cm 3 The powder filler used as component C was used to prepare a fluororubber composition, and a seal was made in the same manner as in Example 1. The resulting seal is designated as Example 13.

[0067] <Comparative Example 1>

[0068] A fluororubber composition without components B and C was prepared, and a seal was fabricated in the same manner as in Example 1. The resulting seal was designated as Comparative Example 1.

[0069] <Comparative Example 2>

[0070] A fluororubber composition without component C was prepared, and a seal was fabricated in the same manner as in Example 1. The resulting seal was designated as Comparative Example 2.

[0071] <Comparative Example 3>

[0072] A liquid material without component B, namely a fluororubber composition of compound 1 containing an alkenyl group and having a perfluoropolyether backbone, was prepared. Otherwise, a seal was fabricated in the same manner as in Example 5. The resulting seal was designated as Comparative Example 3.

[0073] <Comparative Example 4>

[0074] As a powder filler, it is formulated with phenolic resin powder 3 (BellPearl R800, manufactured by BellPearl Company, with a bulk density of d). C 0.60 g / cm 3 To replace component C, a fluororubber composition was prepared, and the seal was fabricated in the same manner as in Example 1. The resulting seal was designated as Comparative Example 4.

[0075] <Comparative Example 5>

[0076] As a powder filler, it is formulated with fluoropolymer (PTFE) powder (LUBRON L-5, manufactured by Daikin Industries, Ltd., with a bulk density of d). C 0.61 g / cm 3 To replace component C, a fluororubber composition was prepared, and the seal was fabricated in the same manner as in Example 1. The resulting seal was designated as Comparative Example 5.

[0077] <Comparative Example 6>

[0078] As a powder filler, it is formulated with MT carbon black (Thermax N990, manufactured by Cancarb Company, with a bulk density of d). C 0.66 g / cm 3 To replace component C, a fluororubber composition was prepared, and the seal was fabricated in the same manner as in Example 1. The resulting seal was designated as Comparative Example 6.

[0079] <Comparative Example 7>

[0080] Relative to 100 parts by mass of component A, 1 part by mass of the liquid material used in Example 5, namely compound 1 which has a perfluoropolyether backbone and does not contain alkenes in its molecular structure, was further incorporated as component B to prepare a fluororubber composition. Otherwise, a seal was manufactured in the same manner as in Example 2. The resulting seal was designated as Comparative Example 7. It should be noted that the density d of component B... B It is 1.88 g / cm 3 .

[0081] [Table 1]

[0082]

[0083] [Table 2]

[0084]

[0085] (Experimental Methods)

[0086] <Plasma Resistance>

[0087] The seals from Examples 1 to 13 and Comparative Examples 1 to 7 were placed in a small plasma etching machine (manufactured by SHINKO SEIKI Co., Ltd.) and exposed to O2 plasma for 30 minutes. The mass reduction rate before and after exposure was calculated. Cases with a mass reduction rate less than 0.7% were designated as Evaluation A, and cases with a mass reduction rate greater than 0.7% were designated as Evaluation B. Furthermore, the presence of particle precipitation on the surface of the seals after exposure to O2 plasma was visually confirmed. It should be noted that a 1500W high-frequency power supply was used for O2 plasma irradiation. O2 and CF4 were used as the reaction gases, with a flow rate ratio of 50:1. The pressure was set to 100 Pa.

[0088] <Presence or absence of component B exudation>

[0089] The seals of Examples 1 to 13 and Comparative Examples 2 to 7 were pressed onto a black acrylic plate. The case in which no transfer marks caused by component B were found on the seal was designated as evaluation A, and the case in which transfer marks caused by component B were found on the seal was designated as evaluation B.

[0090] <XPS Measurement>

[0091] For Examples 1 to 13 and Comparative Examples 1 to 7, the surface and cross-section of the sealing component were irradiated with X-rays using X-ray photoelectron spectroscopy. The peak area of ​​the C1s peak at 282–288 eV from the CH bond was measured during X-ray irradiation and used as A. CH The peak area from the CF bond at 288–296 eV was measured as A. CF Then, calculate A (when X-rays are irradiated onto the surface of the seal). CF / A CH ) / (A when X-rays are irradiated at the position farthest from the seal surface in the cross-section of the seal) CF / A CH Cases with a ratio of 2 or higher are designated as evaluation A, and cases with a ratio less than 2 are designated as evaluation B. Here, the position furthest from the seal surface in the seal profile is the center of the circular profile of the seal, i.e., the O-ring.

[0092] It should be noted that in X-ray photoelectron spectroscopy, data shift occurs due to electrical charge. Therefore, based on the XPS data of fluororubber (manufactured by Viton A and DuPont Elastomer Company) recorded in the NIST X-ray Photoelectron Spectroscopy Database (https: / / srdata.nist.gov / xps / Default.aspx), the peak area A of 282–288 eV from the CH bond in the C1s peak was calculated after aligning the F1s peak with 688.80. CH and the peak area A from the CF bond at 288–296 eV. CF .

[0093] <Hardness>

[0094] For the crosslinked rubber used to form the seals of Examples 1 to 13 and Comparative Examples 1 to 7, the hardness was measured using a type A hardness tester in accordance with JISK 6253-3:2012.

[0095] <Tension Properties>

[0096] For the crosslinked rubber forming the seals of Examples 1 to 13 and Comparative Examples 1 to 7, tensile tests were performed at standard test temperatures using dumbbell-shaped No. 3 test pieces with a thickness of 2 mm, in accordance with JISK 6251:2017, and the tensile strength at cut, elongation at cut, and tensile stress at 100% elongation were measured.

[0097] Compression Permanent Deformation

[0098] For test pieces in which the seals of Examples 1 to 13 and Comparative Examples 1 to 7 were cut in half, the compression set was measured in accordance with JIS K6262:2013 at a test time of 72 hours and a test temperature of (200±2)℃.

[0099] (Experimental Results)

[0100] The test results are shown in Tables 1 and 2. As can be seen from Tables 1 and 2, Examples 1 to 13 exhibit both excellent plasma resistance (such as low mass loss rate) and the effect of inhibiting the exudation of component B. In contrast, in Comparative Examples 1 to 7, one of these effects is less pronounced.

[0101] -Industry Applicability-

[0102] This invention is useful in the field of fluororubber compositions and rubber molded articles formed using the fluororubber compositions.

Claims

1. A fluororubber composition, characterized in that: The fluororubber composition contains components A, B, and C. Component A is a base rubber containing hydrogen-containing fluororubber as the main component. Component B is a compound with a perfluoropolyether backbone. Component C has a bulk density of 0.4 g / cm³. 3 The following are powder fillers, and component B contains an alkenyl group in part or all of its molecules. When the density of component B is set to d B Let p be the content of component B relative to 100 parts by mass of component A. B Let the bulk density of component C be d. C Let p be the content of component C relative to 100 parts by mass of component A. C At that time, (p C / d C ) / (p B / d B )≥4.

2. The fluororubber composition according to claim 1, characterized in that: The proportion of compounds containing an alkenyl group in component B is 20% or more by mass.

3. The fluororubber composition according to claim 1, characterized in that: The B component includes both compounds containing an alkenyl group within the molecule and compounds not containing an alkenyl group within the molecule.

4. The fluororubber composition according to any one of claims 1 to 3, characterized in that: The compound containing an alkenyl group in component B is a liquid material.

5. The fluororubber composition according to any one of claims 1 to 3, characterized in that: Component C contains silicon dioxide and / or resin powder.

6. The fluororubber composition according to any one of claims 1 to 3, characterized in that: The fluororubber composition also contains a crosslinking agent.

7. The fluororubber composition according to claim 6, characterized in that: The crosslinking agent is an organic peroxide.

8. The fluororubber composition according to any one of claims 1 to 3, characterized in that: The fluororubber composition also contains a crosslinking aid.

9. A rubber molded article, characterized in that: The rubber molded article is formed by crosslinking the fluororubber composition according to any one of claims 1 to 8.

10. The rubber molded article according to claim 9, characterized in that: The rubber molded product is a sealing component.

11. The rubber molded article according to claim 10, characterized in that: The seal is used in a semiconductor manufacturing apparatus.

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