JP6918734B2 - An uncrosslinked rubber composition, a rubber product produced using the uncrosslinked rubber composition, and a method for producing the same. - Google Patents

Description

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

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

Japanese Patent No. 4381087 Japanese Patent No. 4628814 Japanese Patent No. 47778782 Japanese Patent No. 6134391 Japanese Unexamined Patent Publication No. 2001-348462

In the preparation of an uncrosslinked rubber composition for producing a rubber product such as a sealant made of fluororubber, when an organic peroxide and a crosslinking aid are added to the fluororubber as a rubber component and kneaded with a roll, the organic peroxide is present. Since the oxides and cross-linking aids are liquefied and the compatibility of the organic peroxides and cross-linking aids with the fluororubber is low, those that were not absorbed by the fluororubber must be added at a low rate. It adheres to the surface of the roll and functions like a lubricant, causing slippage and the kneading may not proceed smoothly. Further, since the fluororubber becomes brittle by absorbing the liquid organic peroxide and the cross-linking aid, it becomes difficult to maintain the uncross-linked rubber composition wound around the roll, and the uncross-linked rubber composition falls from the roll. The kneading may be interrupted. Therefore, the fluororubber rubber product has a problem that the kneading processability is inferior in the preparation of the uncrosslinked rubber composition for producing the fluororubber product.

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

The uncrosslinked rubber composition of the present invention contains hydrogen-containing fluororubber other than polyvinylidene fluoride as the main component of the rubber component, and also contains an organic peroxide, a cross-linking aid, and polyvinylidene fluoride, and the cross-linking is performed. der ratio 2.0 to 3.0 with respect to the content of the organic peroxide content of auxiliaries is, when the radiation is irradiated, the carbon of the rubber component - bond between hydrogen is cleaved you further contains hydrogen sites protecting agent is a compound that binds to a radical of the resulting carbon.

Rubber products of the present invention is formed by the rubber component is composed by crosslinking Rutotomoni, rubber composition the hydrogen site protection agent to the carbon of the rubber component is bonded in the non-cross-linked 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 , and radiation is applied to the heated product. it is shall be irradiated with.

According to the uncrosslinked rubber composition of the present invention, polyvinylidene fluoride can be used as an organic peroxide and a crosslinking aid by containing polyvinylidene fluoride having a relatively high compatibility with the organic peroxide and the crosslinking aid. It absorbs and is smoothly kneaded with the rubber component, and is reinforced by suppressing brittleness by polyvinylidene fluoride, and as a result, excellent kneading processability 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 component of the rubber component, and also contains an organic peroxide, a crosslinking aid, and the like. Contains PVDF. The uncrosslinked rubber composition according to this embodiment is suitable for producing rubber products, particularly sealing materials such as O-rings used in semiconductor process devices using 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 a relatively high compatibility with the organic peroxide and the crosslinking aid. It is smoothly kneaded with the rubber component, and is reinforced by suppressing brittleness by PVDF, and as a result, excellent kneading workability 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 in which hydrogen is bonded to the main chain of a polymer. The content of the hydrogen-containing fluororubber other than PVDF in the rubber component is more than 50% by mass, and from the viewpoint of obtaining excellent physical properties, it is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 100% by mass. %. The rubber component may contain a hydrogen-free fluororubber other than PVDF, a hydrogen-free fluororubber such as a polymer of tetrafluoroethylene (TFE) (PTFE), or a silicone rubber.

Examples of hydrogen-containing fluororubbers other than PVDF include a copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) (dual FKM), vinylidene fluoride (VDF) and hexafluoropropylene (HFP). Tetrafluoroethylene (TFE) and tetrafluoroethylene (TFE) (ternary FKM), tetrafluoroethylene (TFE) and propylene (Pr) copolymer (FEP), vinylidene fluoride (VDF) and propylene (Pr) And tetrafluoroethylene (TFE), a copolymer of ethylene (E) and tetrafluoroethylene (TFE) (ETFE), ethylene (E), tetrafluoroethylene (TFE) and perfluoromethylvinyl ether ( Copolymer with PMVE), copolymer of vinylidene fluoride (VDF) and tetrafluoroethylene (TFE) and perfluoromethyl vinyl ether (PMVE), vinylidene fluoride (VDF) and perfluoromethyl vinyl ether (PMVE) Examples thereof include a copolymer of. As the hydrogen-containing fluororubber other than PVDF, it is preferable to use one or more of these, and from the viewpoint of obtaining excellent physical properties, one containing vinylidene fluoride (VDF) as a monomer may be used. It is more preferable to use a ternary FKM. Hydrogen-containing fluororubbers other than PVDF preferably have iodine or bromine in their molecules 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, and di-t-. Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, α, α-bis (t-butyl peroxy) -p-diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexin-3, benzoyl peroxide, t-butylperoxybenzene, t-butylperoxymaleic acid, t-butylper Examples thereof include oxyisopropyl carbonate and t-butylperoxybenzoate. As the organic peroxide, it is preferable to use one or more of these, and from the viewpoint of obtaining excellent physical properties, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is used. It is more preferable to use it.

The content (A) of the organic peroxide is preferably 0.5 parts by mass or more and 2.5 parts by mass or less, and more preferably 0.5 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of obtaining excellent physical properties. It is equal to or more than 2.0 parts by mass and less than 2.0 parts by mass.

The cross-linking aid is a compound that binds so as to interpose between the molecules of the rubber component when the rubber component is cross-linked by an organic peroxide. Examples of the cross-linking aid include triallyl cyanurate, trimetalyl isocyanurate, triallyl isocyanurate, triacylformal, 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. It is preferable to use one or more of these as the cross-linking aid, and it is more preferable to use triallyl isocyanurate from the viewpoint of obtaining excellent physical properties.

The content (B) of the cross-linking aid is preferably 1 part by mass or more and 10 parts by mass or less, and 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. Is. The content (B) of the cross-linking aid is preferably higher than the content (A) of the organic peroxide from the viewpoint of obtaining excellent physical properties. The ratio (B / A) of the content of the cross-linking aid (B) to the content of the organic peroxide (A) is preferably from the viewpoint of reacting the cross-linking aid in just proportion and obtaining excellent physical properties. It is 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 form a part of the rubber component, but the absorption of the organic peroxide and the processing aid is enhanced to obtain excellent kneading processability, and the uncrosslinked according to the embodiment is obtained. From the viewpoint of increasing the tear strength of the rubber product using the rubber composition and obtaining excellent pressure-resistant crushing property, it is preferably in the form of powder and is dispersed in the rubber component.

By the way, for example, in a fluororubber sealing material used in a semiconductor process device or the like, when the rubber component deteriorates when used in a plasma atmosphere, a powdery material having high plasma resistance dispersed there remains, and the powder-like material remains. There is a problem that particles are emitted and contaminate the inside of the device. 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 powdered PVDF is preferably 1 μm or more and 100 μm or less from the viewpoint of obtaining excellent pressure-resistant crushing property of the rubber product.

The PVDF content (C) is a rubber component from the viewpoint of obtaining excellent kneading processability, suppressing sink marks, and obtaining excellent physical characteristics in the rubber product using the uncrosslinked rubber composition according to the embodiment. It is 3 parts by mass or more and 9.8 parts by mass or less, preferably 5 parts by mass or more and 9.7 parts by mass or less with respect to 100 parts by mass. The PVDF content (C) may be equal to or greater than the sum of the organic peroxide content (A) and the cross-linking aid content (B) from the viewpoint of obtaining excellent kneading processability. preferable. The ratio (C / (A + B)) of the PVDF content (C) to the sum of the organic peroxide content (A) and the cross-linking 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 protectant. A hydrogen site protectant is a compound that binds to a carbon radical generated by breaking the carbon-hydrogen bond of a rubber component when irradiated with radiation during the production of a rubber product.

The hydrogen site protectant is a compound having 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 having an alkenyl group bonded to a carbon radical of a rubber component in the molecule. It is preferable to contain the compound of. Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group and the like. The alkenyl group is preferably a vinyl group among these.

Examples of the compound having a perfluoroskeleton having an alkenyl group in the molecule include a compound having a perfluoropolyether structure and a compound having a perfluoroalkylene structure. Examples of the compound having a siloxane skeleton having an alkenyl group in the molecule include a polymer of methylvinylsiloxane, a polymer of dimethylsiloxane, a copolymer of dimethylsiloxane and methylvinylsiloxane, and dimethylsiloxane, methylvinylsiloxane and methylphenyl. Examples thereof include a copolymer with siloxane. In addition, an organopolysiloxane containing an alkenyl group in the molecule, which is an addition-polymerized liquid silicone rubber, can be mentioned. As the hydrogen site protectant, it is preferable to use one or more of these.

The content of the hydrogen site protectant is preferably 1 part by mass or more and 20 parts by mass or less, and 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 enhancing plasma resistance. ..

The uncrosslinked rubber composition according to the embodiment may contain a reinforcing material such as carbon black or silica, a plasticizer, a processing aid, a vulcanization accelerator, an antiaging agent, or the like, depending on the rubber product to be produced. .. However, when used in the production of rubber products where the generation of particles in a plasma atmosphere is a problem, the content of powdery inorganic fillers such as carbon black, silica, and metal oxides contains hydrogen. It is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and most preferably 0 parts by mass with respect to 100 parts by mass of the fluororubber.

The uncrosslinked rubber composition according to the embodiment can be prepared by using an open rubber kneader such as an open roll or a closed rubber kneader such as a kneader. Of these, excellent kneading workability 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 in a cavity of a preheated mold, then the mold is compacted, and then, in that state, a predetermined molding temperature and a predetermined molding temperature and a predetermined amount. Hold for a predetermined molding time at the molding pressure. At this time, the uncrosslinked rubber composition according to the embodiment is formed into a cavity shape, and the rubber component is crosslinked by an organic peroxide to lose its 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. Then, the rubber product can be obtained by opening the mold, taking out the molded product from the inside, and cooling the molded product. The molded product taken out from the mold may be further heat-treated at a heating temperature of 150 ° C. or higher and 250 ° C. or lower and a heating time of 2 hours or more and 6 hours or less.

When the uncrosslinked rubber composition according to the embodiment contains powdery PVDF, excellent pressure-resistant crushing property is exhibited, and when a rubber product used in a plasma atmosphere is manufactured, 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, the irradiation causes cross-linking at the interface between the rubber component, which is the starting point of crack generation, and PVDF, and they are integrated, thereby inhibiting the growth of cracks.

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 200 kGy or less, and 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, the 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 ternary FKM (manufactured by Daiel G912 Daikin Kogyo Co., Ltd.) with a rubber component was used to apply 2,5-dimethyl-2,5-di of an organic peroxide to 100 parts by mass of this rubber component. (T-Butyl Peroxy) hexane (Perhexa 25B manufactured by Nippon Oil & Fats Co., Ltd.) 1.5 parts by mass, cross-linking aid triallyl isocyanurate (manufactured by Tyke Nihon Kasei Co., Ltd.) 4 parts by mass, powdered PVDF (manufactured by Daikin Industries, Ltd.) , Average particle size: 7 μm) 5 parts by mass, and 10 parts by mass of a perfluoro skeleton compound (SIFEL3590-N manufactured by Shinetsu Chemical Industry Co., Ltd.) having a vinyl group in the molecule of the hydrogen site protectant (I) are added and kneaded. The uncrosslinked rubber composition was prepared. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 2.0 hours.

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

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

<Example 2>
The same operation as in Example 1 was carried out except that the sheet-shaped rubber composition obtained by heat treatment was used as a crosslinked rubber sheet without irradiation with γ-rays. 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 carried out 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 carried out 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 blended rubber containing 90% by mass and 10% by mass of ternary FKM and PVDF (manufactured by Daikin Industries, Ltd.), that is, PVDF was contained so as to form a part of the rubber component. The same operation as in Example 1 was performed except for the above. 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 compound having a siloxane skeleton having a vinyl group (manufactured by KE-1830 Shin-Etsu Chemical Co., Ltd.) was added in the molecule of the hydrogen site protectant (II) instead of the hydrogen site protectant (I). The same operation as was performed. The kneading time required to obtain 4 kg of a uniform uncrosslinked rubber composition was 2.0 hours.

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

<Reference example>
The same operation as in Example 1 was carried out except that powdery PTFE (manufactured by Daikin Industries, Ltd., average particle size: 27 μm) was added instead of the powdery PVDF. 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 at an elongation rate of 10% using a microwave plasma generator. , Mass loss, presence of cracks, and presence of particles were investigated. In the test, O ₂ and CF ₄ were used as reaction gases, and in the O ₂ plasma irradiation test, their flow rate ratio was set to 50: 1, and in the CF ₄ plasma irradiation test, their flow rate ratio was set to 1:50. The reaction pressure was 100 Pa and the plasma irradiation time was 60 minutes.

<Tensile characteristics>
The crosslinked rubber sheets prepared in Examples 1 to 6, Comparative Examples, and Reference Examples were subjected to a tensile test based on JIS K6251, and 100% modulus (M ₁₀₀ : tensile stress at 100% elongation) and tensile strength. (TB) and elongation at cutting (EB) were measured.

<Compression set>
The crosslinked rubber sheets prepared in Examples 1 to 6, Comparative Examples, and Reference Examples were measured for compression set at a test time of 72 hours and a test temperature of 200 ° C. based on JISK6262: 2013.

<40% crush crack>
The crosslinked rubber sheets prepared in Examples 1 to 6, Comparative Examples, and Reference Examples were heat-treated at 150 ° C. for 24 hours, and then the presence or absence of cracks when compressed by 40% was visually confirmed.

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

According to Table 1, Examples 1 to 6 to which PVDF was added had less than half the kneading time of the uncrosslinked rubber composition as compared with Comparative Examples to which PVDF was not added, and therefore, the kneading processability was excellent. I understand.

Comparing Examples 1 and 2, Example was irradiated with γ-rays after heat molding 1 than in Example 2 was not performed irradiation of γ-rays, resistance to O ₂ plasma resistance is excellent, also is crush-resistant It turns out to be excellent. This is because the irradiation with γ-rays causes cross-linking at the interface between the ternary FKM and PVDF, which is the rubber component that is the starting point of crack generation, and they are integrated, thereby inhibiting the growth of cracks. Inferred.

Comparing Examples 1, 3 and 4, it is observed that the _{O 2 plasma resistance tends to decrease as the content of the powdered PVDF increases.} In addition, there is a tendency for the compression set to increase.

Comparing Examples 3 and 5, Example 3 to which powdered PVDF was added was kneaded because the kneading time was shorter than that of Example 5 in which PVDF was contained so as to form a part of the rubber component. It can be seen that the workability is excellent and the pressure-resistant crushing property is excellent.

Comparing Examples 1 and 6, the addition of either the hydrogen site protectant (I) or the hydrogen site protectant (II) affects the kneading processability, plasma resistance, physical characteristics, and pressure resistance. It can be seen that it shows excellent performance.

In the reference example in which powdered PTFE was added, excellent kneading workability could be obtained, but it was found that plasma resistance and pressure resistance were low. This is because PTFE has higher plasma resistance than the rubber component ternary FKM, so that only powdery PTFE remains when the ternary FKM deteriorates, and even if γ-rays are irradiated, It is presumed that this is because no cross-linking occurs between the ternary FKM of the rubber component and the PTFE that does not contain a hydrogen atom bonded to a carbon atom.

The present invention is useful in the technical fields of uncrosslinked rubber compositions, rubber products produced using them, and methods for producing the same.

Claims (7)

An uncrosslinked rubber composition containing hydrogen-containing fluororubber other than polyvinylidene fluoride as the main component of the rubber component, and also containing an organic peroxide, a cross-linking aid, and polyvinylidene fluoride.
Wherein Ri der ratio of 2.0 to 3.0 with respect to the content of the organic peroxide content of the crosslinking aid,
When radiation is irradiated, the carbon of the rubber component - hydrogen-site protection agent further uncrosslinked rubber composition you containing a compound that binds to bind to the radical of the carbon produced is cleaved between hydrogen. In the uncrosslinked rubber composition according to claim 1,
An uncrosslinked rubber composition in which the polyvinylidene fluoride is in the form of a powder and is dispersed and contained in the rubber component. In the uncrosslinked rubber composition according to claim 1 or 2.
An uncrosslinked rubber composition in which the content of 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. In the uncrosslinked rubber composition according to any one of claims 1 to 3.
An uncrosslinked rubber composition in which the ratio of the content of polyvinylidene fluoride to the sum of the content of the organic peroxide and the content of the crosslinking aid is 0.9 or more and 2 or less. Claims 1 to be constructed the rubber component is crosslinked in the uncrosslinked rubber composition described in any one of the 4 Rutotomoni, the hydrogen site protection agent is formed of a rubber composition which is bonded to the carbon of the rubber component Rubber products. In the rubber product according to claim 5.
A rubber product in which the rubber product is a sealing material. The uncrosslinked rubber composition according to any one of claims 1 to 4 is heated to a predetermined temperature to crosslink the rubber component with the organic peroxide , and radiation is applied to the heated one. method of manufacturing a rubber product that be irradiated.