JP2019172897A - Uncrosslinked rubber composition and rubber product produced using the same and method for producing the same - Google Patents

Abstract

To provide an uncrosslinked rubber composition having excellent mixing workability.SOLUTION: An uncrosslinked rubber composition contains a hydrogen-containing fluorine rubber other than a polyvinylidene fluoride, as the main component of a rubber component, and contains an organic peroxide, a crosslinking aid, and a polyvinylidene fluoride.SELECTED DRAWING: None

Description

  The present invention relates to an uncrosslinked rubber composition, a rubber product produced using the composition, and a method for producing the rubber product.

  In the field of semiconductor process equipment and the like, it is known to use a fluororubber sealing material (for example, Patent Documents 1 to 5).

Japanese Patent No. 438187 Japanese Patent No. 4628814 Japanese Patent No. 47788782 Japanese Patent No. 6134391 JP 2001-348462 A

  In preparing an uncrosslinked rubber composition for producing a rubber product such as a fluororubber sealant, when an organic peroxide and a crosslinking aid are added to the fluororubber of the rubber component and kneaded with a roll, Oxides and cross-linking aids become liquid, and organic peroxides and cross-linking aids have low compatibility with fluoro rubber. In some cases, it adheres to the roll surface and functions like a lubricant, causing slipping and kneading not proceeding smoothly. Further, since the fluororubber becomes brittle by absorbing the liquid organic peroxide and the crosslinking aid, it becomes difficult to maintain the uncrosslinked rubber composition around the roll, and the uncrosslinked rubber composition falls from the roll. In some cases, kneading is interrupted. Therefore, the rubber product made of fluoro rubber has a problem that the kneadability is inferior in the preparation of an uncrosslinked rubber composition for producing the rubber product.

  An object of the present invention is to provide an uncrosslinked rubber composition having excellent kneadability.

  The uncrosslinked rubber composition of the present invention contains a hydrogen-containing fluororubber other than polyvinylidene fluoride as a main component of the rubber component, and also contains an organic peroxide, a crosslinking aid, and polyvinylidene fluoride.

  The rubber product of the present invention is formed of a rubber composition formed by crosslinking the rubber component in the uncrosslinked rubber composition of the present invention.

  In the method for producing a rubber product of the present invention, the uncrosslinked rubber composition of the present invention is heated to a predetermined temperature to crosslink the rubber component with the organic peroxide.

  According to the uncrosslinked rubber composition of the present invention, the polyvinylidene fluoride contains the organic peroxide and the crosslinking aid by containing the polyvinylidene fluoride having a relatively high compatibility with the organic peroxide and the crosslinking aid. While being absorbed and kneaded smoothly with the rubber component, embrittlement is suppressed and reinforced by polyvinylidene fluoride, and as a result, excellent kneadability can be obtained.

  Hereinafter, embodiments will be described in detail.

  The uncrosslinked rubber composition according to the embodiment contains a hydrogen-containing fluororubber other than polyvinylidene fluoride (hereinafter referred to as “PVDF”) as a main rubber component, an organic peroxide, a crosslinking aid, Contains PVDF. The uncrosslinked rubber composition according to this embodiment is suitable for the production of rubber products, in particular, sealing materials such as O-rings used in semiconductor processing devices that use plasma such as semiconductor etching devices and plasma CVD devices. Used for.

  According to the uncrosslinked rubber composition according to the embodiment, PVDF absorbs the organic peroxide and the crosslinking aid by containing PVDF having relatively high compatibility with the organic peroxide and the crosslinking aid. While being kneaded smoothly with the rubber component, embrittlement is suppressed and reinforced by PVDF, and as a result, excellent kneadability can be obtained.

  Here, the rubber component mainly contains hydrogen-containing fluororubber other than PVDF. The “hydrogen-containing fluororubber” in the present application is a fluororubber containing carbon having hydrogen bonded to the main chain of the polymer. The content of the hydrogen-containing fluororubber other than PVDF in the rubber component is more than 50% by mass, and preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass from the viewpoint of obtaining excellent physical properties. %. The rubber component may contain hydrogen-free fluorine rubber such as tetrafluoroethylene (TFE) polymer (PTFE) or silicone rubber in addition to hydrogen-containing fluorine rubber other than PVDF.

  Examples of hydrogen-containing fluororubbers other than PVDF include copolymers (binary FKM) of vinylidene fluoride (VDF) and hexafluoropropylene (HFP), vinylidene fluoride (VDF) and hexafluoropropylene (HFP). Copolymer of tetrafluoroethylene (TFE) (ternary FKM), copolymer of tetrafluoroethylene (TFE) and propylene (Pr), vinylidene fluoride (VDF) and propylene (Pr) Copolymer of ethylene and tetrafluoroethylene (TFE), copolymer of ethylene (E) and tetrafluoroethylene (TFE) (ETFE), ethylene (E), tetrafluoroethylene (TFE) and perfluoromethyl vinyl ether ( PMVE), vinylidene fluoride (VD) ) And a copolymer of tetrafluoroethylene (TFE) and perfluoromethylvinylether (PMVE), copolymer of vinylidene fluoride and (VDF) and perfluoromethylvinylether (PMVE) and the like. It is preferable to use one or more of these hydrogen-containing fluororubbers other than PVDF. From the viewpoint of obtaining excellent physical properties, it is preferable to use one containing vinylidene fluoride (VDF) as a monomer. More preferably, ternary FKM is more preferably used. The hydrogen-containing fluororubber other than PVDF preferably has iodine or bromine in the molecule from the viewpoint of obtaining excellent physical properties.

  The organic peroxide is a thermal cross-linking agent that cross-links the rubber component when heated to a predetermined temperature. Examples of the organic peroxide include 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-butylperoxide Oxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexyne-3, benzoyl peroxide, t-butylperoxybenzene, t-butylperoxymaleic acid, t-butylper Examples thereof include oxyisopropyl carbonate and t-butyl peroxybenzoate. As the organic peroxide, one or more of these are preferably used. From the viewpoint of obtaining excellent physical properties, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is used. More preferably, it is used.

  From the viewpoint of obtaining excellent physical properties, the organic peroxide content (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 with respect to 100 parts by mass of the rubber component. It is not less than 2.0 parts by mass.

  The crosslinking aid is a compound that bonds so as to be interposed between the rubber component molecules when the rubber component is crosslinked with an organic peroxide. Examples of the crosslinking aid include triallyl cyanurate, trimethallyl isocyanurate, triallyl isocyanurate, triacryl formal, triallyl trimellitate, N, N′-m-phenylenebismaleimide, dipropargyl terephthalate, diallyl Phthalate, 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, hexaallylphosphoramide, N, N, N ', N'-tetraallyl lid Amides, N, N, N ′, N′-tetraallylmalonamide, trivinylisocyanurate, 2,4,6-trivinylmethyltrisiloxane, tri (5-norbornene-2-methylene) cyanurate, triallyl phosphite Etc. One or more of these crosslinking assistants are preferably used, and triallyl isocyanurate is more preferably used from the viewpoint of obtaining excellent physical properties.

  The content (B) of the crosslinking aid is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 2 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the rubber component from the viewpoint of obtaining excellent physical properties. It is. The content (B) of the crosslinking aid is preferably larger than the content (A) of the organic peroxide from the viewpoint of obtaining excellent physical properties. The ratio (B / A) of the content (B) of the crosslinking aid to the content (A) of the organic peroxide is preferably from the viewpoint of obtaining excellent physical properties while allowing the crosslinking aid to react without excess or deficiency. 1.0 or more and 4.0 or less, more preferably 2.0 or more and 3.0 or less.

  PVDF may be contained so as to constitute a part of the rubber component, and while improving the absorbability of the organic peroxide and processing aid to obtain excellent kneading workability, uncrosslinked according to the embodiment From the viewpoint of increasing the tear strength of a rubber product using the rubber composition and obtaining excellent crushing resistance, it is preferably in powder form and dispersed in a rubber component.

  By the way, for example, in a fluororubber sealing material used in a semiconductor process apparatus or the like, when used in a plasma atmosphere and the rubber component deteriorates, a powder-like material with high plasma resistance remaining therein remains, There is a problem that particles are emitted to contaminate the inside of the apparatus. However, since PVDF has the same plasma resistance as hydrogen-containing fluororubber other than PVDF in the rubber component, even if powdery PVDF is dispersed and contained in the rubber component, the generation of such particles is suppressed. be able to. The average particle size of the powdery PVDF is preferably 1 μm or more and 100 μm or less from the viewpoint of obtaining excellent crushing resistance of the rubber product.

  The content of PVDF (C) is a rubber component from the viewpoint of obtaining excellent kneading workability and suppressing sink marks and obtaining excellent physical properties in rubber products using the uncrosslinked rubber composition according to the embodiment. It is 3 to 9.8 parts by mass, preferably 5 to 9.7 parts by mass with respect to 100 parts by mass. From the viewpoint of obtaining excellent kneading processability, the PVDF content (C) may be equal to or more than the sum of the organic peroxide content (A) and the crosslinking agent content (B). preferable. The ratio (C / (A + B)) of the PVDF content (C) to the sum of the organic peroxide content (A) and the crosslinking aid content (B) is preferably 0.5 or more and 6 or less, More preferably, it is 0.9 or more and 2 or less.

  The uncrosslinked rubber composition according to the embodiment may further contain a hydrogen site protecting agent. The hydrogen site protecting agent is a compound that binds to a radical of carbon generated by breaking a carbon-hydrogen bond of a rubber component when irradiated with radiation during the production of a rubber product.

  The hydrogen site protecting agent is a compound of a perfluoro skeleton having an alkenyl group bonded to a carbon radical of a rubber component in the molecule and / or a siloxane skeleton having an alkenyl group bonded to a carbon radical of a rubber component in the molecule. It is preferable that the compound is included. Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group. Among these, the alkenyl group is preferably a vinyl group.

  Examples of the perfluoro skeleton compound having an alkenyl group in the molecule include a perfluoropolyether structure compound and a perfluoroalkylene structure compound. Examples of the siloxane skeleton compound having an alkenyl group in the molecule include a polymer of methyl vinyl siloxane, a polymer of dimethyl siloxane, a copolymer of dimethyl siloxane and methyl vinyl siloxane, dimethyl siloxane, methyl vinyl siloxane and methyl phenyl. Examples thereof include copolymers with siloxane. In addition, organopolysiloxane containing an alkenyl group in the molecule, which is an addition polymerization liquid silicone rubber. It is preferable to use one or more of these hydrogen site protecting agents.

  The content of the hydrogen site protecting agent is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 5 parts by mass or more and 15 parts by mass or less, with respect to 100 parts by mass of the rubber component, from the viewpoint of improving plasma resistance. .

  The uncrosslinked rubber composition according to the embodiment may contain a reinforcing material such as carbon black and silica, a plasticizer, a processing aid, a vulcanization accelerator, an antiaging agent, and the like depending on the rubber product to be manufactured. . However, when used in the manufacture of rubber products where the generation of particles in a plasma atmosphere becomes a problem, the content of powdery inorganic fillers such as carbon black, silica, metal oxides, etc. Preferably it is 5 mass parts or less with respect to 100 mass parts of fluororubber, More preferably, it is 3 mass parts or less, Most preferably, it is 0 mass part.

  The uncrosslinked rubber composition according to the embodiment can be prepared using an open rubber kneader such as an open roll or a closed rubber kneader such as a kneader. Among these, excellent kneadability can be obtained particularly in an open type rubber kneader such as an open roll.

  Next, a method for producing a rubber product using the uncrosslinked rubber composition according to the embodiment will be described.

  In the method for producing a rubber product, first, a predetermined amount of the uncrosslinked rubber composition according to the embodiment is filled into a preheated mold cavity, and then clamped, and in that state, a predetermined molding temperature and a predetermined Hold the molding pressure for a predetermined molding time. At this time, the uncrosslinked rubber composition according to the embodiment is molded into the shape of the cavity, and the rubber component is crosslinked by the organic peroxide to lose plasticity. 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. And a rubber product can be obtained by opening a metal mold | die, taking out a molded product from the inside, and cooling. Note that the molded product taken out from the mold may be further subjected to heat treatment at a heating temperature of 150 ° C. or more and 250 ° C. or less and a heating time of 2 hours or more and 6 hours or less.

  When the powdered PVDF is contained in the uncrosslinked rubber composition according to the embodiment, excellent crush resistance is expressed, and when a rubber product used in a plasma atmosphere is produced, cracks are generated in the plasma atmosphere. From the viewpoint of suppression, it is preferable to irradiate the molded product after heating with radiation. At this time, irradiation with radiation causes cross-linking at the interface between the rubber component and PVDF, which is the starting point of crack generation, and they are integrated, thereby inhibiting crack growth.

  Examples of the radiation include α rays, β rays, γ rays, electron beams, ions, and the like. Among these, it is preferable to use electron beams or γ rays. The radiation dose is preferably 10 kGy or more and 200 kGy or less, more preferably 20 kGy or more and 80 kGy or less, from the viewpoint of suppressing the generation of particles.

(Kneading of uncrosslinked rubber composition and preparation of crosslinked rubber sheet)
In each of the following Examples 1 to 6, Comparative Examples, and Reference Examples, an uncrosslinked rubber composition was kneaded and a crosslinked rubber sheet was prepared using the kneaded rubber composition. Each configuration is also shown in Table 1.

<Example 1>
Using an 8-inch open roll, a rubber component ternary FKM (Daiel G912, manufactured by Daikin Industries, Ltd.) is used with 100 parts by mass of the rubber component, 2,5-dimethyl-2,5-dioxide of organic peroxide. 1.5 parts by mass of (t-butylperoxy) hexane (Perhexa 25B manufactured by Nippon Oil & Fats Co., Ltd.), 4 parts by mass of triallyl isocyanurate as a crosslinking aid (manufactured by Taik Nippon Kasei Co., Ltd.), powdered PVDF (manufactured by Daikin Industries, Ltd.) And 5 parts by mass of the average particle size: 7 μm) and 10 parts by mass of a perfluoro skeleton compound having a vinyl group in the molecule of the hydrogen site protecting agent (I) (SIFEL3590-N manufactured by Shin-Etsu Chemical Co., Ltd.) An uncrosslinked rubber composition was prepared. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 2.0 hours.

  Subsequently, the 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, and then heat-treated at a heating temperature of 200 ° C. and a heating time of 4 hours to form a sheet-like rubber composition Got.

  Then, this sheet-like rubber composition was irradiated with γ rays with an irradiation dose of 30 kGy to obtain a crosslinked rubber sheet.

<Example 2>
The same operation as in Example 1 was performed except that a sheet-like rubber composition obtained by heat treatment was used as a crosslinked rubber sheet without γ-ray irradiation. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 2.0 hours.

<Example 3>
The same operation as in Example 1 was performed except that the amount of powdered PVDF added was 10 parts by mass with respect to 100 parts by mass of the rubber component. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 1.5 hours.

<Example 4>
The same operation as in Example 1 was performed except that the amount of powdered PVDF added was 30 parts by mass with respect to 100 parts by mass of the rubber component. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 1.0 hour.

<Example 5>
The rubber component was composed of a blend rubber containing 90% by mass and 10% by mass of ternary FKM and PVDF (manufactured by Daikin Industries, Ltd.), that is, PVDF was included so as to constitute a part of the rubber component. Except that, the same operation as in Example 1 was performed. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 2.5 hours.

<Example 6>
Example 1 except that a siloxane skeleton compound having a vinyl group in the molecule of the hydrogen site protecting agent (II) (KE-1830, manufactured by Shin-Etsu Chemical Co., Ltd.) was added in place of the hydrogen site protecting agent (I). The same operation was performed. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 2.0 hours.

<Comparative example>
The same operation as in Example 1 was performed except that powdery PVDF was not added. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 5.0 hours.

<Reference example>
It replaced with powdery PVDF and performed operation similar to Example 1 except having added powdery PTFE (the Daikin Kogyo company make, average particle diameter: 27 micrometers). The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 2.0 hours.

(Test method)
<Plasma resistance>
The crosslinked rubber sheets prepared in Examples 1 to 6, Comparative Examples, and Reference Examples were subjected to an O ₂ plasma irradiation test and a CF ₄ plasma irradiation test using a microwave plasma generator at an elongation rate of 10%. The weight loss, the presence or absence of cracks, and the presence or absence of generation of particles were examined. In the test, O ₂ and CF ₄ were used as reaction gases. In the O ₂ plasma irradiation test, the flow rate ratio was 50: 1, and in the CF ₄ plasma irradiation test, the flow rate ratio was 1:50. The reaction pressure was 100 Pa and the plasma irradiation time was 60 minutes.

<Tensile properties>
Examples 1-6, Comparative Examples, and the crosslinked rubber sheet prepared in each of Reference Example, subjected to tensile tests based on JIS K6251, 100% modulus _(M 100: tensile stress at 100% elongation), tensile strength (TB) and elongation at break (EB) were measured.

<Compression set>
About the crosslinked rubber sheet prepared in each of Examples 1 to 6, Comparative Example, and Reference Example, compression set was measured based on JISK6262: 2013 with a test time of 72 hours and a test temperature of 200 ° C.

<40% crushing crack>
About the crosslinked rubber sheet prepared by each of Examples 1-6, a comparative example, and a reference example, after performing the heat processing for 24 hours at 150 degreeC, the presence or absence of the crack when 40% was compressed was confirmed visually.

(Test results)
The test results are shown in Table 1.

  According to Table 1, in Examples 1 to 6 to which PVDF was added, the kneading time of the uncrosslinked rubber composition was less than half that of the comparative example to which PVDF was not added, and thus kneadability was excellent. I understand.

Comparing Examples 1 and 2, Example 1 that was irradiated with γ rays after heat forming had better O ₂ plasma resistance than Example 2 that was not irradiated with γ rays. It turns out that it is excellent. This is because γ-ray irradiation causes crosslinking at the interface between the rubber component ternary FKM and PVDF, which is the starting point of crack generation, and they are integrated, thereby inhibiting crack growth. Inferred.

When Examples 1, 3, and 4 are compared, when the content of powdery PVDF is increased, the tendency to decrease the O ₂ plasma resistance is recognized. Moreover, the tendency for compression set to become large is also recognized.

  Comparing Examples 3 and 5, Example 3 to which powdery PVDF was added was kneaded because the kneading time was shorter than Example 5 in which PVDF was incorporated so as to constitute a part of the rubber component. It can be seen that the processability is excellent and the crushing resistance is excellent.

  Comparing Examples 1 and 6, the addition of any of the hydrogen site protecting agent (I) and the hydrogen site protecting agent (II) has an effect on kneading processability, plasma resistance, physical properties, and pressure crush resistance. It turns out that it shows the outstanding performance.

  In addition, in the reference example which added powdery PTFE, although the outstanding kneading workability was able to be obtained, it turns out that plasma resistance and crush resistance are low. This is because PTFE has higher plasma resistance than the ternary FKM of the rubber component, and therefore only the powdery PTFE remains when the ternary FKM deteriorates, and even when γ rays are irradiated, This is presumably because no crosslinking occurs between the ternary FKM of the rubber component and PTFE not containing a hydrogen atom bonded to a carbon atom.

  INDUSTRIAL APPLICABILITY The present invention is useful in the technical field of an uncrosslinked rubber composition, a rubber product produced using the composition, and a production method thereof.

Claims (7)

  An uncrosslinked rubber composition containing a hydrogen-containing fluororubber other than polyvinylidene fluoride as a main component of a rubber component, and containing an organic peroxide, a crosslinking aid, and polyvinylidene fluoride. In the uncrosslinked rubber composition according to claim 1,
An uncrosslinked rubber composition in which the polyvinylidene fluoride is in a powder form and is dispersed in the rubber component. In the uncrosslinked rubber composition according to claim 1 or 2,
An uncrosslinked rubber composition, wherein a content of the polyvinylidene fluoride is 3 parts by mass or more and 9.8 parts by mass or less with respect to 100 parts by mass of the rubber component.   A rubber product formed of a rubber composition in which the rubber component in the uncrosslinked rubber composition according to any one of claims 1 to 3 is crosslinked. In the rubber product according to claim 4,
A rubber product, wherein the rubber product is a sealing material.   A method for producing a rubber product, comprising: heating the uncrosslinked rubber composition according to any one of claims 1 to 3 to a predetermined temperature to crosslink the rubber component with the organic peroxide. In the manufacturing method of the rubber product according to claim 6,
A method for producing a rubber product, wherein the heated product is irradiated with radiation.