JP2019085475A - Sealant rubber material and sealant including the same - Google Patents

Abstract

To obtain a sealant having stable antistatic performance and excellent discriminability.SOLUTION: A sealant rubber material contains an uncrosslinked, crosslinkable fluorine rubber, an ionic liquid, and a crosslinker.SELECTED DRAWING: None

Description

  The present invention relates to a rubber material for a sealing material and a sealing material using the same.

  In the sealing material made of fluorine rubber, it is known to contain a conductive material for the purpose of antistatic. For example, Patent Document 1 discloses a sealing material formed of a rubber composition obtained by blending a fluororubber with a conductive additive such as acetylene black or ketjen black.

Japanese Patent Application Publication No. 2007-137977

  In the case of a rubber composition compounded with a conductive additive such as acetylene black or ketjen black, the electric characteristics are not stable due to the dispersed state of the conductive additive, and a large amount of metal impurities are contained, so semiconductor production is required There is a problem that it is difficult to use in equipment and food related applications. There is also a problem that it can not be used for applications where identification is required because of black.

  An object of the present invention is to obtain a sealing material having stable antistatic performance and excellent discrimination.

  The present invention is a rubber material for a sealing material containing an uncrosslinked crosslinkable fluororubber, an ionic liquid and a crosslinking agent.

  The present invention is a sealing material formed of a rubber composition in which the crosslinkable fluororubber of the rubber material for a sealing material of the present invention is crosslinked.

  According to the present invention, since the ionic liquid is contained, the obtained sealing material can obtain excellent discrimination as well as stable antistatic performance.

  Hereinafter, the embodiment will be described in detail.

  The rubber material for a sealing material according to the embodiment is suitably used for manufacturing a sealing material, in particular, a sealing material such as an O-ring used in a semiconductor manufacturing apparatus using a plasma such as an etching apparatus or a plasma CVD apparatus. It is.

  The rubber material for a sealing material according to the embodiment contains an uncrosslinked crosslinkable fluororubber, an ionic liquid, and a crosslinking agent.

  As the crosslinkable fluororubber, for example, a polymer of tetrafluoroethylene (TFE) (PTFE), a polymer of vinylidene fluoride (VDF) (PVDF), vinylidene fluoride (VDF) and hexafluoropropylene (HFP) Copolymer (binary FKM), copolymer of vinylidene fluoride (VDF), hexafluoropropylene (HFP) and tetrafluoroethylene (TFE) (three-component FKM), tetrafluoroethylene (TFE) and propylene Copolymer (FEP) with (Pr), copolymer of vinylidene fluoride (VDF) with propylene (Pr) and tetrafluoroethylene (TFE), co-polymer of ethylene (E) with tetrafluoroethylene (TFE) Polymer (ETFE), ethylene (E) and tetrafluoroethylene (TF) ) And perfluoromethylvinylether (PMVE), copolymers of vinylidene fluoride (VDF), tetrafluoroethylene (TFE) and perfluoromethylvinylether (PMVE), tetrafluoroethylene (TFE) and perco Examples thereof include copolymers (FFKM) with fluoromethyl vinyl ether (PMVE), copolymers of vinylidene fluoride (VDF) and perfluoromethyl vinyl ether (PMVE), and the like. It is preferable to use 1 type, or 2 or more types in these, and, as for a crosslinkable fluororubber, it is more preferable to use ternary FKM. In the case of peroxide crosslinking, the crosslinkable fluororubber preferably has iodine or bromine in the molecule.

  The ionic liquid is a salt composed of a cationic component and an anionic component, and has a melting point of 100 ° C. or less.

  Examples of the cationic component of the ionic liquid include 1-ethyl-3-methylimidazolium, 1-methyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-Octyl-3-methylimidazolium, 1-methyl-2,3-dimethylimidazolium, 1-butyl-2,3-dimethylimidazolium, 1-hexyl-2,3-dimethylimidazolium, 1-octyl- Imidazolium-based cations such as 2,3-dimethylimidazolium; pyridinium-based cations such as 1-octyl-4-methyl-pyridinium, 1-methyl-pyridinium, 1-butyl-pyridinium, 1-hexyl-pyridinium; tributylmethylammonium And aliphatic amine-based cations; pyrazolium-based cations and the like.

  As an anion component, for example, bisfluorosulfonyl imide type anions such as bisfluorosulfonyl imide, bis trifluoromethane sulfonyl imide, bis trifluoro butane sulfonyl imide, and the like; fluorinated sulfonic acid type such as tetrafluoro borate, hexafluoro borate, trifluoro methane sulfonate and the like Anions; fluorinated carboxylic acid-based anions such as trifluoroacetic acid; thiocyanate-based anions; dicyanamide-based anions; tetracyanoborate-based anions and the like.

  The ionic liquid preferably contains one or more of these cationic components and one or more of the anionic components. The cationic component of the ionic liquid is preferably an imidazolium-based cation, a pyridinium-based cation, or an aliphatic amine-based cation. The cation component of the ionic liquid is preferably 1-ethyl-3-methylimidazolium for imidazolium-based cations, and 1-octyl-4-methyl-pyridinium for pyridinium-based cations, and tributyl for aliphatic amine-based cations. Methyl ammonium is preferred. The anion component of the ionic liquid is preferably a bisfluorosulfonylimide type anion, and among these, bistrifluoromethanesulfonylimide and bistrifluorobutanesulfonylimide are more preferable.

  The content of the ionic liquid in the rubber material for a sealing material according to the embodiment is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.1 parts by mass or more with respect to 100 parts by mass of the crosslinkable fluororubber It is 5 parts by mass or less.

  As the crosslinking agent, peroxide is used if it is a peroxide crosslinking system, polyol if it is a polyol crosslinking system, and amine if it is an amine crosslinking system, but the rubber material for a sealing material according to the embodiment is a peroxide crosslinking system. It is preferable to contain peroxide as a crosslinking agent.

  The peroxide of the crosslinking agent may be, for example, 1,1-bis (t-butylperoxy) -3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t -Butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α-bis (t-butylperoxy) -p-diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butyl) Peroxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexyne-3, benzoyl peroxide, t-butylperoxybenzene, t-butylperoxymaleic acid, t-butyl Peroxy isopropyl carbonate, t-butyl peroxy benzoate and the like can be mentioned. It is preferable to use one or more of these peroxides as a crosslinking agent, and more preferable to use 2,5-dimethyl-2,5-di (t-butylperoxy) hexane.

  The peroxide content of the crosslinking agent in the rubber material for a sealing material according to the embodiment is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass with respect to 100 parts by mass of the crosslinkable fluororubber It is 5 parts by mass or less.

  The rubber material for a sealing material according to the embodiment may further contain a crosslinking aid. Examples of crosslinking assistants include triallyl cyanurate, trimethallyl isocyanurate, triallyl isocyanurate, triacrylic formal, triallyl trimellitate, N, N'-m-phenylene bismaleimide, dipropargyl terephthalate, diallyl. Phthalate, tetraallyl terephthalate amide, triallyl phosphate, bismaleimide, fluorinated triallylisocyanurate (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-divinyldodecafluorohexane, hexaallylphosphoramide, N, N, N ', N'- tetraallylphthalamide, N, N, N , N'- tetraallyl malonamide, trivinyl isocyanurate, 2,4,6-vinyl methyl trisiloxane, tri (5-norbornene-2-methylene) cyanurate, triallyl phosphite, and the like. It is preferable to use 1 type, or 2 or more types of these crosslinking adjuvants, and it is more preferable to use triallyl isocyanurate.

  The content of the crosslinking aid in the rubber material for a sealing material according to the embodiment is preferably 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the crosslinkable fluororubber.

  The rubber material for a sealing material according to the embodiment may contain silicone rubber or the like which is a rubber component other than the crosslinkable fluororubber. In addition, the rubber material for a sealing material according to the embodiment contains a reinforcing material such as carbon black or silica, a plasticizer, a processing aid, a vulcanization accelerator, an antiaging agent, etc. depending on the use of the sealing material to be produced. It may be However, when manufacturing a sealing material used in a semiconductor manufacturing apparatus in which generation of particles in a plasma atmosphere causes a problem, the content of powdery or granular inorganic filler such as carbon black, silica, metal oxide, etc. Is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less, and most preferably 0 parts by mass (not blended) with respect to 100 parts by mass of the crosslinkable fluororubber. Furthermore, in the case of a sealing material used in a semiconductor manufacturing apparatus in which generation of particles in a plasma atmosphere is a problem, a crosslinkable fluorine rubber composition containing a perfluoroelastomer having two or more alkenyl groups in the crosslinkable fluorine rubber It is preferred to use

  The rubber material for a sealing material according to the embodiment can be manufactured using an open rubber kneader such as an open roll or a closed rubber kneader such as a kneader.

  According to the non-crosslinked rubber composition according to the embodiment of the above configuration, since the ionic liquid is contained, in the obtained sealing material, excellent identification performance can be obtained together with stable antistatic performance.

  Next, an example of the manufacturing method of the sealing material using the rubber material for sealing materials which concerns on embodiment is demonstrated.

  In the production of the seal material, first, a predetermined amount of the rubber material for a seal material according to the embodiment is filled in a cavity of a mold preheated to a predetermined molding temperature, and then clamped and then the predetermined molding is performed. The primary thermal crosslinking is performed by holding the pressure for a predetermined molding time. This molding may be press molding or may be injection molding. The molding temperature is, for example, 150 ° C. or more and 180 ° C. or less. The molding pressure is, for example, 0.1 MPa or more and 25 MPa or less. The molding time is, for example, 3 minutes or more and 20 minutes or less.

  Subsequently, after the mold is opened and the molded product is taken out, it is put into a heating furnace in which the inside of the furnace is preheated to a predetermined heating temperature, and in that state, secondary heat is maintained for a predetermined heating time. Crosslink. The heating temperature is, for example, 200 ° C. or more and 300 ° C. or less. The heating time is, for example, 1 hour or more and 48 hours or less.

  Then, after taking out the molded product from the heating furnace, it is irradiated with radiation to crosslink it as necessary. Examples of radiation include α rays, β rays, γ rays, electron beams, ions and the like. As the radiation, it is preferable to use an electron beam or γ ray among them. The irradiation dose of radiation is preferably 10 kGy or more and 100 kGy or less, more preferably 30 kGy or more and 80 kGy or less, from the viewpoint of enhancing plasma resistance.

  Thus, the sealing material formed of the rubber composition in which the crosslinkable fluororubber of the rubber material for a sealing material according to the embodiment is crosslinked is obtained.

The volume resistivity of the rubber composition forming the sealing material is preferably 1.0 × 10 ¹³ Ω · cm or less, more preferably 1.0 × 10 ¹² Ω · cm or less. These surface resistivity and volume resistivity are measured based on JISK6271-1: 2015.

  The half life of the chargeability test of the rubber composition forming the sealing material is preferably 2.0 seconds or less, more preferably 1.0 seconds or less. The half life of this chargeability test is measured according to method A (half life measurement method) defined in JIS L1094: 2014.

  The compression set of the rubber composition forming the sealing material is preferably 30.0% or less. This compression set is measured as a test time of 72 hours and a test temperature of 150 ° C. based on JIS K6262: 2013.

(Rubber composition)
The rubber compositions of Examples 1 to 15 and Comparative Examples 1 to 11 below were produced. The respective configurations are also shown in Tables 1 to 4.

Example 1
Crosslinkable fluororubber A ternary system FKM for peroxide crosslinking (manufactured by TENFLON P459 SOLVAY), 1-ethyl-3-methylimidazolium of ionic liquid A with respect to 100 parts by mass of the crosslinkable fluororubber A. 1.0 parts by mass of bistrifluoromethanesulfonyl imide (EMI-N111 manufactured by Mitsubishi Materials Corporation), 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (perhexa 25B peroxy) peroxydioxide crosslinking agent A non-crosslinked rubber composition was prepared by blending and kneading 1.5 parts by mass of Co., Ltd., and 4.0 parts by mass of triallyl isocyanurate (manufactured by Tyke Nippon Kasei Co., Ltd.) as a crosslinking aid. Subsequently, this uncrosslinked rubber composition is press-molded at a molding temperature of 165 ° C., a molding pressure of 5 MPa, and a molding time of 15 minutes for primary thermal crosslinking, and then the heating temperature of 200 ° C. and the heating time of 4 hours for the secondary heat. It was crosslinked to obtain a sheet-like rubber composition. Then, the sheet-like rubber composition was subjected to radiation crosslinking by being irradiated with γ-rays of an irradiation dose of 30 kGy. A sheet-like rubber composition produced by irradiating this γ-ray was referred to as Example 1.

Examples 2 to 9
Instead of the ionic liquid A, 1-ethyl-3-methylimidazolium bistrifluorobutanesulfonylimide (EMI-N 441 manufactured by Mitsubishi Materials Corporation) of the ionic liquid B, 1-butyl-3-methylimidazolium of the ionic liquid C -Bis trifluoromethanesulfonyl imide (BMI-N111 manufactured by Mitsubishi Materials Corporation), 1-Butyl 3-methylimidazolium of ionic liquid D-Bistrifluorobutanesulfonylimide (BMI-N 441 manufactured by Mitsubishi Materials), 1 of ionic liquid E -Ethyl-3-methylimidazolium bisfluorosulfonyl imide (Eleccel AS-110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonylimide of ionic liquid F (Eleccel AS-210 Daiichi Kogyo Seiyaku Co., Ltd.), ionic liquid G 1-octyl-4-methylpyridinium bisfluorosulfonylimide (Eccel AS-804, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), ionic liquid H (Echcel MP-457, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and ionic liquid I The sheet-like rubber composition produced by the same operation as Example 1 was used as Examples 2-9 except having used tributyl methyl ammonium bis trifluoro methanesulfonyl imide (FC-4400 3M Japan company make). .

Examples 10 to 13
Except that the blending amount of the ionic liquid C is 0.1 parts by mass, 0.5 parts by mass, 1.5 parts by mass, and 2.0 parts by mass with respect to 100 parts by mass of the crosslinkable fluororubber A, respectively The sheet-like rubber composition produced by the same operation as Example 3 was set to Examples 10-13.

Comparative Example 1
A sheet-like rubber composition produced in the same manner as in Example 1 except that the ionic liquid A was not blended, was taken as Comparative Example 1.

<Comparative Examples 2 to 9>
Polymeric Antistatic Agent A (Pelestat HC250 manufactured by Sanyo Chemical Industries, Ltd.) 5.0 parts by mass, Polymeric Antistatic Agent B (Perektron) in place of the ionic liquid A per 100 parts by mass of the crosslinkable fluororubber A 5.0 parts by weight of PVL Sanyo Chemical Industries, Ltd. 10 parts by weight of polymer type antistatic agent C (Pebax MV 1074 SP 01 manufactured by Arkema), 10 parts by weight of polymer type antistatic agent D (Pebax MH2030 Arkema) 15 parts by mass of molecular type antistatic agent E (Entila SD100 manufactured by Mitsui / Dupont Polychemicals Co., Ltd.), 15 parts by mass of polymer type antistatic agent F (Entila MK400 manufactured by Mitsui / Dupont Polychemicals Co., Ltd.) 10 parts by mass of an inhibitor (Sanconol TBX-8310 manufactured by Sanko Chemical Industry Co., Ltd.) and 5.0 parts by mass of a lithium salt-containing antistatic agent The sheet-like rubber composition produced by the same operation as Example 1 was set as Comparative Examples 2-9, except that.

Examples 14 and 15
In ternary system FKM (made by Daiel G-912 Daikin Industries, Ltd.) for peroxide crosslinking of crosslinkable fluororubber B, 5.0 parts by mass of ionic liquid A and 100 parts by mass of this crosslinkable fluororubber B as a crosslinking agent An uncrosslinked rubber composition prepared by blending and kneading 1.5 parts by mass of peroxide, 4.0 parts by mass of a cross-linking aid, and 10 parts by mass of hydrophobic silica (Aerosil R972 Evonik Co., Ltd.) of powdery inorganic filler A sheet-like rubber composition produced in the same manner as in Example 1 except for the use was made Example 14. A sheet-like rubber composition produced in the same manner as in Example 14 except that the ionic liquid C was used instead of the ionic liquid A, was taken as example 15.

Comparative Example 11
A sheet-like rubber composition produced in the same manner as in Example 14 except that the ionic liquid A was not blended, was taken as Comparative Example 11.

(Test and evaluation method)
<Surface resistivity and volume resistivity>
The volume resistivity of each of the rubber compositions of Examples 1 to 15 and Comparative Examples 1 to 11 was measured based on JIS K 6271: 2008. And, as for volume resistivity, those having 1.0 × 10 ¹² Ω · cm or less are AA, those exceeding 1.0 × 10 ¹² Ω · cm and 1.0 × 10 ¹³ Ω · cm or less are A, Those exceeding 1.0 × 10 ¹³ Ω · cm were evaluated as B.

<Chargeability test>
The rubber compositions of Examples 1 to 8 and 10 to 15 and Comparative Examples 1 to 2, 4, 8 to 9, and 11 are each measured according to method A (half-life measurement method) defined in JIS L 1094: 2014. The chargeability test was conducted to determine the half life. With regard to the half life, those with 1.0 seconds or less were evaluated as AA, those with 1.0 seconds or more but 2.0 seconds or less as A, and those with 2.0 seconds or more as B.

<Compression set>
For each of Examples 1 to 13 and Comparative Examples 1 to 5 and 8 to 9, the compression set was measured at a test time of 72 hours and a test temperature of 150 ° C. based on JIS K6262: 2013. Then, with respect to compression set, those with 30.0% or less were evaluated as A, and those with more than 30.0% were evaluated as B.

(Test results)
The test results are shown in Tables 1 to 4. According to these results, it can be seen that if the ionic liquid is blended with the crosslinkable fluororubber, antistatic can be achieved without losing the compression set, even without using powdery or granular antistatic agents. In addition, excellent discrimination can be obtained.

  The present invention is useful in the technical fields of rubber materials for sealing materials and sealing materials using the same.

Claims (5)

  A rubber material for a sealing material, which contains an uncrosslinked crosslinkable fluororubber, an ionic liquid and a crosslinking agent. In the rubber material for a sealing material according to claim 1,
The rubber material for sealing materials, wherein the cationic component of the ionic liquid contains an imidazolium-based cation, a pyridinium-based cation, or an aliphatic amine-based cation. The rubber material for a sealing material according to claim 1 or 2
The rubber material for sealing materials, wherein the anion component of the ionic liquid contains bisfluorosulfonyl imide type anion. In the rubber material for a sealing material according to any one of claims 1 to 3,
The rubber material for sealing materials whose content of the said ionic liquid is 0.01 mass part or more and 10 mass parts or less with respect to 100 mass parts of said crosslinkable fluororubber.   A sealing material formed of a rubber composition in which the crosslinkable fluororubber of the rubber material for a sealing material according to any one of claims 1 to 4 is crosslinked.