JP6890081B2 - Rubber material for sealing material and sealing material using it - Google Patents

Description

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

It is known that a fluororubber sealing material contains a conductive material to prevent its antistatic property. For example, Patent Document 1 discloses a sealing material formed of a rubber composition in which a conductive additive such as acetylene black or Ketjen black is mixed with fluororubber.

Japanese Unexamined Patent Publication No. 2007-137977

In the case of a rubber composition containing a conductive additive such as acetylene black or Ketjen black, the electrical characteristics are not stable due to the dispersed state of the conductive additive, and the semiconductor production requires cleanliness because it contains a large amount of metal impurities. There was a problem that it was difficult to use for equipment and food-related applications. In addition, there is also a problem that it cannot be used for applications that require identification because of its black color.

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

The present invention is a rubber material for a sealing material containing a crosslinkable fluororubber, an ionic liquid, and a crosslinking agent , and does not contain a powdery or granular inorganic filler . a copolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene, cation component of the ionic liquid is a imidazolium Kachio down or pyridinium cation, the content of the ionic liquid, the crosslinking It is 0.5 parts by mass or more with respect to 100 parts by mass of fluororubber .

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 antistatic performance and excellent discriminability.

Hereinafter, embodiments will be described in detail.

The rubber material for a sealing material according to the embodiment is preferably used for manufacturing a sealing material, particularly a sealing material such as an O-ring used in a semiconductor manufacturing apparatus using plasma such as an etching apparatus and a plasma CVD apparatus. Is.

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

Examples of the crosslinkable fluororubber include 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) (ternary FKM), tetrafluoroethylene (TFE) and propylene Copolymer with (Pr) (FEP), Copolymer of vinylidene fluoride (VDF), propylene (Pr) and tetrafluoroethylene (TFE), Co-polymer of ethylene (E) and tetrafluoroethylene (TFE) Polymer (ETFE), copolymer of ethylene (E), tetrafluoroethylene (TFE) and perfluoromethylvinyl ether (PMVE), vinylidene fluoride (VDF), tetrafluoroethylene (TFE) and perfluoromethylvinyl ether ( Copolymer with PMVE), Copolymer with tetrafluoroethylene (TFE) and perfluoromethyl vinyl ether (PMVE) (FFKM), Copolymer with vinylidene fluoride (VDF) and perfluoromethyl vinyl ether (PMVE) And so on. As the crosslinkable fluororubber, it is preferable to use one or more of these, and it is more preferable to use a ternary FKM. When the crosslinkable fluororubber is crosslinked with peroxide, it is preferable to have 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 lower.

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

Examples of the anion component include bisfluorosulfonylimide-based anions such as bisfluorosulfonylimide, bistrifluoromethanesulfonylimide, and bistrifluorobutanesulfonylimide; fluorinated sulfonic acid-based anions such as tetrafluoroborate, hexafluoroborate, and trifluoromethanesulfonate. Anions; fluorinated carboxylic acid anions such as trifluoroacetic acid; thiocyanate anions; disianamide anions; tetracyanoborate anions and the like.

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

The content of the ionic liquid in the rubber material for the sealing material according to the embodiment is preferably 0.01 part by mass or more and 10 parts by mass or less, and more preferably 0.1 part 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 cross-linking agent, peroxide is used in the case of a peroxide cross-linking system, polyol in the case of a polyol cross-linking system, and amine in the case of an amine cross-linking system. Therefore, it is preferable to contain a peroxide as a cross-linking agent.

Examples of the cross-linking agent peroxide include 1,1-bis (t-butylperoxy) -3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, and di-t. -Butyl peroxide, t-butyl hexane peroxide, dicumyl peroxide, α, α-bis (t-butyl peroxy) -p-diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butyl) Peroxy) Hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexin-3, benzoyl peroxide, t-butylperoxybenzene, t-butylperoxymaleic acid, t-butyl Examples thereof include peroxyisopropyl carbonate and t-butylperoxybenzoate. As the cross-linking agent peroxide, it is preferable to use one or more of these, and it is more preferable to use 2,5-dimethyl-2,5-di (t-butylperoxy) hexane.

The content of the cross-linking agent peroxide in the rubber material for the 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 cross-linking aid. Examples of the cross-linking aid include triallyl cyanurate, trimetalyl isocyanurate, triallyl isocyanurate, triacrylic formal, triallyl trimellitate, N, N'-m-phenylene bismaleimide, dipropagil terephthalate, and diallyl. Phtalate, tetraallyl terephthalate amide, triallyl phosphate, bismaleimide, fluorinated triallyl isocyanurate (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, hexaallyl phosphoramide, N, N, N', N'-tetraallyl phthalamide, N, N, N', N'-tetraallyl malonamide, trivinyl isocyanurate, 2,4,6-trivinylmethyltrisiloxane, tri (5-norbornen-2) -Methylene) cyanurate, triallyl phosphite and the like. As the cross-linking aid, it is preferable to use one or more of these, and it is more preferable to use triallyl isocyanurate.

The content of the cross-linking aid in the rubber material for the sealing material according to the embodiment is preferably 0.1 part 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 the sealing material according to the embodiment may contain silicone rubber or the like which is a rubber component other than the crosslinkable fluororubber. Further, 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 manufactured. May be. However, when manufacturing a sealing material used in a semiconductor manufacturing apparatus in which the generation of particles in a plasma atmosphere is a problem, the content of powdery or granular inorganic filler such as carbon black, silica, and metal oxide is used. Is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, further 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. Further, 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 fluororubber composition containing a perfluoroelastomer having two or more alkenyl groups in the crosslinkable fluororubber. It is preferable to use.

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

According to the uncrosslinked rubber composition according to the embodiment having the above configuration, since it contains an ionic liquid, the obtained sealing material can obtain stable antistatic performance and excellent distinctiveness.

Next, an example of a method for manufacturing a sealing material using the rubber material for the sealing material according to the embodiment will be described.

In the production of the sealing material, first, a predetermined amount of the rubber material for the sealing material according to the embodiment is filled in the cavity of the mold preheated to a predetermined molding temperature, then the mold is clamped, and then the predetermined molding is performed in that state. The primary thermal cross-linking is carried out by holding the pressure for a predetermined molding time. This molding may be press molding or injection molding. The molding temperature is, for example, 150 ° C. or higher and 180 ° C. or lower. 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 opening the mold and taking out the molded product, the inside of the furnace is placed in a heating furnace preheated to a predetermined heating temperature, and in that state, the secondary heat is held for a predetermined heating time. Crosslink. The heating temperature is, for example, 200 ° C. or higher and 300 ° C. or lower. 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, if necessary, it is irradiated with radiation to carry out radiation cross-linking. Examples of radiation include α-rays, β-rays, γ-rays, electron beams, ions and the like. Of these, electron beams or γ-rays are preferably used as radiation. The irradiation dose of radiation is preferably 10 kGy or more and 100 kGy or less, and more preferably 30 kGy or more and 80 kGy or less from the viewpoint of enhancing plasma resistance.

In this way, a sealing material formed of a rubber composition in which the crosslinkable fluororubber of the rubber material for the sealing material according to the embodiment is crosslinked can be 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 second or less. The half-life of this chargeability test is measured according to the method A (half-life measurement method) specified 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 based on JIS K6262: 2013 with a test time of 72 hours and a test temperature of 150 ° C.

(Rubber composition)
The following rubber compositions of Examples 1 to 15 and Comparative Examples 1 to 11 were prepared. Each configuration is also shown in Tables 1 to 4.

<Example 1>
Crosslinkable fluororubber A Peroxide In a ternary FKM (manufactured by Technoflon P459 SOLVAY) for crosslinking, with respect to 100 parts by mass of this crosslinkable fluororubber A, 1-ethyl-3-methylimidazolium of ionic liquid A. Bistrifluoromethanesulfonylimide (EMI-N111, manufactured by Mitsubishi Materials Corporation) 1.0 part by mass, cross-linking agent peroxide 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (Perhexa 25B Nihon Kasei) An uncrosslinked rubber composition was prepared by blending 1.5 parts by mass of (manufactured by Tyke) and 4.0 parts by mass of triallyl isocyanurate (manufactured by Tyke Nihon Kasei Co., Ltd.) as a crosslinking aid. Subsequently, this uncrosslinked rubber composition was 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 cross-linking, and then secondary heat was applied at a heating temperature of 200 ° C. and a heating time of 4 hours. Crosslinking was performed to obtain a sheet-shaped rubber composition. Then, the sheet-shaped rubber composition was irradiated with γ-rays having an irradiation dose of 30 kGy to undergo radiation cross-linking. A sheet-shaped rubber composition prepared by irradiating this γ-ray was used as Example 1.

<Examples 2 to 9>
Instead of ionic liquid A, 1-ethyl-3-methylimidazolium bistrifluorobutanesulfonylimide (EMI-N441, manufactured by Mitsubishi Materials Corporation) of ionic liquid B and 1-butyl-3-methylimidazolium of ionic liquid C, respectively. -Bistrifluoromethanesulfonylimide (BMI-N111 manufactured by Mitsubishi Materials Co., Ltd.), 1-butyl-3-methylimidazolium bistrifluorobutanesulfonylimide (BMI-N441 manufactured by Mitsubishi Materials Co., Ltd.) of ionic liquid D, 1 of ionic liquid E -Ethyl-3-methylimidazolium bisfluorosulfonylimide (Elexel AS-110 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 1-Ethyl-3-methylimidazolium bistrifluoromethanesulfonylimide (Elexel AS-210) of ionic liquid F (Manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 1-octyl-4-methylpyridium bisfluorosulfonylimide of ionic liquid G (manufactured by Elexel AS-804 Daiichi Kogyo Seiyaku Co., Ltd.), Ion liquid H (Electyl MP-457 Daiichi Kogyo) Sheet-shaped rubber produced by the same operation as in Example 1 except that tributylmethylammonium bistrifluoromethanesulfonylimide (manufactured by FC-4400 3M Japan) of ionic liquid I was used. The compositions were designated as Examples 2-9.

<Examples 10 to 13>
Except that the amount of the ionic liquid C was 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-shaped rubber composition produced by the same operation as in Example 3 was designated as Examples 10 to 13.

<Comparative example 1>
A sheet-shaped rubber composition prepared by the same operation as in Example 1 except that the ionic liquid A was not blended was designated as Comparative Example 1.

<Comparative Examples 2-9>
Instead of the ionic liquid A, 5.0 parts by mass of the polymer type antistatic agent A (Perestat HC250 manufactured by Sanyo Kasei Kogyo Co., Ltd.) and 5.0 parts by mass of the polymer type antistatic agent B (Perectron) with respect to 100 parts by mass of the crosslinkable fluororubber A. PVL Sanyo Kasei Kogyo Co., Ltd.) 5.0 parts by mass, polymer type antistatic agent C (manufactured by Pevacs MV1074SP01 Alchema) 10 parts by mass, polymer type antistatic agent D (manufactured by Pevacs MH2030 Alchema) 10 parts by mass, high Molecular antistatic agent E (manufactured by Entila SD100 Mitsui / Dupont Polychemical) 15 parts by mass, polymer type antistatic agent F (manufactured by Entila MK400 Mitsui / Dupont Polychemical) 15 parts by mass, and Li salt-containing charge Sheet-shaped rubber produced by the same operation as in Example 1 except that 10 parts by mass of an inhibitor (Sanconol TBX-8310 manufactured by Sanko Kagaku Kogyo Co., Ltd.) and 5.0 parts by mass of a Li salt-containing antistatic agent were used. The compositions were designated as Comparative Examples 2-9.

<Examples 14 and 15>
In a ternary FKM (manufactured by Daiel G-912 Daikin Kogyo Co., Ltd.) for cross-linking the crosslinkable fluororubber B with peroxide, 5.0 parts by mass of the ionic liquid A and 5.0 parts by mass of the cross-linking agent with respect to 100 parts by mass of the crosslinkable fluororubber B. An uncrosslinked rubber composition obtained by blending 1.5 parts by mass of peroxide, 4.0 parts by mass of a crosslinking aid, and 10 parts by mass of hydrophobic silica (manufactured by Aerodil R972 Ebony) as a powdery inorganic filler and kneading the mixture. A sheet-shaped rubber composition prepared by the same operation as in Example 1 except that it was used was designated as Example 14. Further, a sheet-shaped rubber composition prepared by the same operation as in Example 14 except that the ionic liquid C was used instead of the ionic liquid A was designated as Example 15.

<Comparative Example 11>
A sheet-shaped rubber composition prepared by the same operation as in Example 14 except that the ionic liquid A was not blended was designated as Comparative Example 11.

(Test / 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 K6271: 2008. As for the volume resistivity, the one having 1.0 × 10 ¹² Ω · cm or less is AA, and the one having more than 1.0 × 10 ¹² Ω · cm and 1.0 × 10 ¹³ Ω · cm or less is A. Those exceeding 1.0 × 10 ¹³ Ω · cm were evaluated as B.

<Charability test>
For each of the rubber compositions of Examples 1 to 8 and 10 to 15 and Comparative Examples 1 to 2, 4, 8 to 9, and 11, according to the method A (half-life measurement method) specified in JIS L1094: 2014. A chargeability test was performed to measure the half-life. The half-life was evaluated as AA for those with a half-life of 1.0 seconds or less, A for those with a half-life of more than 1.0 seconds and 2.0 seconds or less, and B for those with a half-life of more than 2.0 seconds.

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

(Test results)
The test results are shown in Tables 1 to 4. From these results, it can be seen that if an ionic liquid is blended with the crosslinkable fluororubber, antistatic can be achieved without impairing the compression set without using a powdery or granular antistatic agent. In addition, excellent distinctiveness 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 (7)

A rubber material for a sealing material that contains a crosslinkable fluororubber, an ionic liquid, and a crosslinking agent , and does not contain a powdery or granular inorganic filler.
The crosslinkable fluororubber is a copolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene.
Cation component of the ionic liquid is a imidazolium Kachio down or pyridinium cation,
A rubber material for a sealing material in which the content of the ionic liquid is 0.5 parts by mass or more with respect to 100 parts by mass of the crosslinkable fluororubber. In the rubber material for a sealing material according to claim 1,
A rubber material for a sealing material in which the anion component of the ionic liquid contains a bisfluorosulfonylimide anion. In the rubber material for a sealing material according to claim 1 or 2.
The content of the ionic liquid, wherein the cross-linkable fluorine rubber relative to 100 parts by weight of 1 0 part by weight or less sealing material for a rubber material. In the rubber material for a sealing material according to any one of claims 1 to 3,
A rubber material for a sealing material, wherein the cross-linking agent is peroxide and the content thereof is 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the cross-linking fluororubber. A sealing material formed of a rubber composition obtained by cross-linking the crosslinkable fluororubber of the rubber material for a sealing material according to any one of claims 1 to 4. In the sealing material according to claim 5,
For the crosslinked rubber composition, the volume resistivity measured based on JIS K6271: 2008 is 1.0 × 10. ¹² Sealing material of Ω ・ cm or less. In the sealing material according to claim 5 or 6,
Sealing material used in semiconductor manufacturing equipment.