JP2006161032A - Fluororubber/silicone rubber blended rubber composition and molded rubber article produced by curing the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition obtained by blending an uncured perfluoropolyether-type fluororubber composition having good solvent resistance, chemical resistance, heat resistance and low-temperature properties with a silicone rubber composition having good compression set and processability and provide an article produced by curing the rubber composition. <P>SOLUTION: The rubber composition is produced by blending (a) a perfluoropolyether-type fluororubber composition having a crosslinking site of Si-CH=CH<SB>2</SB>with (b) a silicone rubber composition having the same crosslinking system. The molded rubber article is produced by molding and curing the rubber composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is obtained by blending a perfluoropolyether fluororubber uncured composition having good solvent resistance, chemical resistance, heat resistance and low temperature characteristics with a silicone rubber composition having good compression set and processability. The present invention relates to a rubber composition and a rubber molded product obtained by curing the rubber composition.

  Conventional vinylidene fluoride-based fluororubber is an elastomer excellent in heat resistance, chemical resistance, mechanical strength, and the like, and is therefore industrially used in a wide range of fields mainly in the automobile and machine industries.

  However, its chemical resistance is inadequate and easily swells in polar solvents such as ketones, lower alcohols, carbonyls, organic acids, etc. There is a disadvantage that the elongation is extremely lowered. Further, in terms of low temperature characteristics, rubber elasticity is lost at −20 ° C. or lower and the seal material cannot be used. Therefore, there is a general limit to use in cold regions.

  Therefore, in order to improve these drawbacks, a liquid or millable type fluorinated curable composition mainly composed of a perfluoro compound and a fluorinated organohydrogenpolysiloxane has been proposed (Patent Documents 1 to 4: Japanese Patent No. 2990646 (Japanese Patent Laid-Open No. 8-199070), Japanese Patent Laid-Open No. 2000-007835, Japanese Patent Laid-Open No. 2001-106893, Japanese Patent Laid-Open No. 2003-201401).

  However, since these fluorine-containing curable compositions are difficult to be blended with different types of inexpensive rubbers, their molded products are generally expensive, and their usage is limited.

  Furthermore, regarding rubber physical properties and processability, other types of rubbers may have excellent characteristics. Specifically, compared with silicone rubber, it is not as good as silicone rubber in terms of rubber strength, elongation, compression set, roll workability, mold releasability and the like.

  Therefore, it is conceivable to blend these two types of compositions as a composition having the characteristics of the above-mentioned fluorine-containing curable composition and silicone rubber composition, but the composition obtained is not compatible with each other. However, there is a decrease in physical properties and there is no interaction between the blended polymers, so that a delamination phenomenon occurs, resulting in a non-practical rubber.

Japanese Patent No. 2990646 (Japanese Patent Laid-Open No. Hei 8-199070) JP 2000-007835 A JP 2001-106893 A JP 2003-201401 A

  The present invention has been made in order to improve the above situation, and has both the characteristics of a perfluoropolyether-based fluorine-containing rubber composition and a silicone rubber composition, and has no delamination, and this An object is to provide a molded rubber product obtained by molding and curing a rubber composition.

As a result of intensive studies to achieve the above object, the present inventors have found that a silicone rubber composition having the same crosslinking system as the perfluoropolyether-based fluorine-containing rubber composition in which the crosslinking site is Si—CH═CH _2. A rubber composition obtained by mixing and a rubber molded product obtained by molding and curing the rubber composition are found to have characteristics that do not cause extreme degradation and do not cause delamination. It came to.

Accordingly, the present invention provides a rubber composition obtained by mixing the following perfluoropolyether-based fluorine-containing rubber composition and a silicone rubber composition, and a rubber molded product obtained by molding and curing the rubber composition.
Claim 1:
(A) obtained by mixing a perfluoropolyether-based fluorine-containing rubber composition having a crosslinking site of Si—CH═CH ₂ and (b) a silicone rubber composition having the same crosslinking system as this fluorine-containing rubber composition. Rubber composition.
Claim 2:
2. The rubber according to claim 1, wherein the cross-linking system is a peroxide cross-linking type, and the perfluorinated polyether-based fluororubber composition and the silicone rubber composition of the peroxide cross-linking type are mixed. Composition.
Claim 3:
2. The rubber composition according to claim 1, wherein the crosslinking system is an addition crosslinking type, and the addition crosslinking type perfluoropolyether-based fluorine-containing rubber composition and a silicone rubber composition are mixed. .
Claim 4:
The perfluoropolyether-based fluorine-containing rubber composition (a) is
(A) a part of the alkenyl group of the perfluoro compound having at least two alkenyl groups in the molecule and having a divalent perfluoroalkylene structure or a divalent perfluoropolyether structure in the main chain; A polymer formed by adding a compound capable of addition reaction with an alkenyl group having at least two hydrosilyl groups in the molecule,
(B) Crosslinkability comprising a reinforcing filler, and (C) a crosslinking agent having a hydrosilyl group in the molecule or a peroxide crosslinking agent in an amount sufficient to cure the component (A). The rubber composition according to any one of claims 1 to 3, wherein the rubber composition is a fluororubber composition.
Claim 5:
Said silicone rubber composition is
(D) The following average composition formula (I)
(R ¹¹ ) _x SiO _{(4-x) / 2} (I)
(In the formula, R ¹¹ is an unsubstituted or substituted monovalent hydrocarbon group, and x is a number satisfying 1.95 <x <2.05.)
A diorganopolysiloxane represented by the formula: 0.01 to 15 mol% of all R ¹¹ bonded to silicon atoms of the diorganopolysiloxane is a monovalent aliphatic unsaturated hydrocarbon group,
The rubber composition according to any one of claims 1 to 4, which is a silicone rubber composition comprising (E) a reinforcing filler and (F) a crosslinking agent.
Claim 6:
A rubber molded article obtained by molding and curing the rubber composition according to any one of claims 1 to 5.
Claim 7:
The rubber molded product according to claim 6, wherein the molded product is a seal material, an O-ring, a diaphragm, a hose, a cap, or a valve material.

  The composition of the present invention has the characteristics of a perfluoropolyether-based fluororubber composition and a silicone rubber composition, and the molded product obtained by curing does not delaminate. Since it becomes a stable processed product having both characteristics, its industrial utility value is great.

The present invention will be described in further detail below.
As the perfluoropolyether-based fluorine-containing rubber composition in which the crosslinking site is Si—CH═CH ₂ used in the present invention, the above-mentioned Japanese Patent No. 2990646 (JP-A-8-199070), JP-A-2000-007835, JP-A-2001-106893, JP-A-2003-20141 and the like can be used, and the product name SIFEL series (manufactured by Shin-Etsu Chemical Co., Ltd.) is generally used. It is available.

That is, in Japanese Patent Laid-Open No. 8-199070 (Patent Document 1),
(A ′) a fluorine-containing amide compound represented by the following general formula (1),

[Wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group, R ² is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group, Q is the following general formula (2) or the following general formula (3 ) Group

(However, in the formula, R ³ represents an unsubstituted or substituted divalent hydrocarbon group in which one or more of an oxygen atom, a nitrogen atom, and a silicon atom may be interposed during bonding.)

(Wherein R ⁴ and R ⁵ each represent an unsubstituted or substituted divalent hydrocarbon group), Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, and a is It is an integer of 0 or more. ]
(B ′) one or more monovalent perfluorooxyalkyl groups, monovalent perfluoroalkyl groups, divalent perfluorooxyalkylene groups or divalent perfluoroalkylene groups in one molecule, and A composition containing a fluorine-containing organohydrogensiloxane having two or more hydrosilyl groups and (C ′) a catalytic amount of a platinum group compound, wherein the amount of the component (B ′) is an aliphatic non-reactive component in the composition. There is disclosed a curable composition characterized in that the amount of hydrosilyl group (Si-H group) is 0.5 to 5 moles per mole of saturated groups.

  In addition, in Japanese Patent Application Laid-Open No. 2000-007835 (Patent Document 2), (A) a molecule having at least two alkenyl groups and a main chain having a divalent perfluoroalkylene structure or a divalent perfluoro group. A polymer in which a compound capable of addition reaction with an alkenyl group having at least two hydrosilyl groups in the molecule is added to a part of the alkenyl group of the perfluoro compound having a polyether structure, (B) a reinforcing filler, (C) A crosslinkable fluororubber composition comprising a sufficient amount of a crosslinking agent or peroxide crosslinking agent having a hydrosilyl group in the molecule to cure the component (A) Things are disclosed.

  In Japanese Patent Laid-Open No. 2001-106893 (Patent Document 3), the same component (A), component (B), component (C) as in Patent Document 2 described above, and at least one (D ′) component in the molecule A crosslinkable fluororubber composition comprising a surface treatment agent having a fluoroalkyl group or fluoropolyalkyl ether group and a silanol group in the molecule is disclosed.

  Furthermore, in Japanese Patent Application Laid-Open No. 2003-201401 (Patent Document 4), (A ″) a polymer compound represented by the following general formula (4) having a viscosity at 25 ° C. of 1,000 Pa · s or more.

(Where n is an integer of 1 or more, Rf is a divalent perfluoroalkylene group or perfluorooxyalkylene group, Q ¹ is a divalent organic group, and Z is a monovalent organic group).
A crosslinkable fluororubber composition comprising (B ″) a reinforcing filler and (C ″) a peroxide crosslinking agent is disclosed.

Here, in the above formula (4), as the divalent perfluoroalkylene group and divalent perfluorooxyalkylene group (divalent perfluoropolyether group) of Rf, -C _m F _2m- (m = It is preferably a divalent perfluoroalkylene group selected from divalent perfluoroalkylene groups represented by 2 to 15) or groups represented by the following formulas (5), (6) and (7).

(X is independently F or CF ₃ group, r is an integer of 2-6, t, u are 1 or 2, p, q are integers of 0-200, and s is an integer of 0-6, respectively. , P, q, and s are not 0 at the same time.)

(X is the same as described above, and v and w are each an integer of 1 to 50.)

(Y is an integer of 1 to 100.)

In the above formula (4), Q ¹ is a group represented by the following formula (8).

(Wherein R ⁶ is a monovalent hydrocarbon selected from alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups, aryl groups, aralkyl groups, and groups in which some or all of the hydrogen atoms in these groups have been substituted with halogen atoms. Group, R ⁷ is a hydrogen atom or a monovalent hydrocarbon group similar to R ⁶ , R ⁸ is an oxygen atom or an alkylene group having 1 to 8 carbon atoms, a cycloalkylene group, an arylene group, a part of hydrogen atoms of these groups the been substituted with halogen atoms, and divalent hydrocarbon radicals, R ⁹ is the same monovalent hydrocarbon group as R ⁶ is selected from the group formed by combining the above alkylene group and an arylene group, R ¹⁰ is same as R ⁶ Selected from monovalent hydrocarbon groups, monovalent hydrocarbon groups containing an aliphatic unsaturated bond having 2 to 20 carbon atoms, and groups obtained by substituting some or all of the hydrogen atoms of these groups with halogen atoms. Indicates a monovalent hydrocarbon group.)

  Furthermore, in said formula (4), Z is a C1-C30 monovalent organic group which may have the atom chosen from oxygen, nitrogen, sulfur, and silicon in the middle of a coupling | bonding.

  Among these, in particular, at least two alkenyl groups in the molecule (A) described in JP-A-2000-007835 (Patent Document 2) and JP-A-2001-106893 (Patent Document 3) are present. An alkenyl having at least two hydrosilyl groups in the molecule as part of the alkenyl group of the perfluoro compound having a divalent perfluoroalkylene structure or a divalent perfluoropolyether structure in the main chain A polymer formed by addition of a compound capable of undergoing addition reaction with a group, (B) a reinforcing filler, and (C) a peroxide cross-linking agent containing an amount sufficient to cure the component (A). The characteristic crosslinkable fluororubber composition is preferred.

  The composition will be described in more detail. The component (A) of the crosslinkable fluororubber composition of the present invention has (I) at least two alkenyl groups in the molecule, and a divalent paroxy group in the main chain. (II) A compound capable of addition reaction with an alkenyl group having at least two hydrosilyl groups in the molecule is added to a part of the alkenyl group of the perfluoro compound having a fluoroalkylene or divalent perfluoropolyether structure. It is the polymer which becomes.

Here, the perfluoro compound of component (I) is a compound that is technically difficult to synthesize into a high molecular weight polymer such as a resin or rubber, and has at least two alkenyl groups in the molecule. And a linear perfluoro compound having a divalent perfluoroalkylene or divalent perfluoropolyether structure in the main chain, and preferably having a viscosity of 25 to 1,000,000 mm ² / s at 25 ° C. Examples of the perfluoro compound include those represented by the following general formula (i).

[-CH ₂ wherein, D is independently _{-, - CH 2 O -,} - CH 2 OCH 2 -, - Y-NR 15 SO 2 - or -Y-NR ¹⁵ -CO- (where, Y is -CH ₂ or

R ¹⁵ represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group), Rf represents a divalent perfluoroalkylene group or a divalent perfluoropolyether group, and z is independently 0 or 1 is there. Q ′ represents the following general formula (ii), (iii) or (iv)

[Wherein D, z and R ¹⁵ have the same meaning as described above, R ¹⁶ represents an unsubstituted or substituted divalent hydrocarbon group, R ¹⁷ represents an oxygen atom, nitrogen atom, silicon atom and An unsubstituted or substituted divalent hydrocarbon group which may contain one or more sulfur atoms, or the following general formula (v) or (vi)

(R ¹⁸ is an unsubstituted or substituted monovalent hydrocarbon group, R ¹⁹ is a group containing one or more of a carbon atom, oxygen atom, nitrogen atom, silicon atom and sulfur atom in the main chain structure)
It is group shown by these. ]
And a is an integer of 0 or more. ]

Here, Rf is a divalent perfluoroalkylene group or a divalent perfluoropolyether group, and in particular, the divalent perfluoroalkylene group is —C _{m ′} F _{2m ′} —
(However, m ′ = 1 to 10, preferably 2 to 6.)
The divalent perfluoropolyether group is preferably represented by the following formula.

(X is F or CF ₃ group, p ′, q ′, r ′ are p ′ ≧ 1, q ′ ≧ 1, 2 ≦ p ′ + q ′ ≦ 200, particularly 2 ≦ p ′ + q ′ ≦ 110, 0 ≦ r ′ ≦ integer of 6)

(R ′, s ′, and t ′ are integers of 0 ≦ r ′ ≦ 6, s ′ ≧ 0, t ′ ≧ 0, 0 ≦ s ′ + t ′ ≦ 200, particularly 2 ≦ s ′ + t ′ ≦ 110)

(X is F or CF ₃ group, u ′ and v ′ are integers of 1 ≦ u ′ ≦ 100 and 1 ≦ v ′ ≦ 50, respectively)

(W ′ is an integer of 1 ≦ w ′ ≦ 100)

  Next, compounds capable of undergoing an addition reaction with an alkenyl group containing at least two hydrosilyl groups in the molecule of the component (II) include those containing a hydrosilyl group in an organic compound and hydrosilyl groups in an organic silicon compound. However, in consideration of dispersibility and heat resistance, the compounds of the following formula (vii) or formula (viii) are desirable.

[Wherein D, z and Rf have the same meaning as described above. W is the following general formula (ix)

(Wherein R ¹⁸ is an unsubstituted or substituted monovalent hydrocarbon group, b is 1, 2 or 3 in the case of the compound of formula (vii) and 2 or 3 in the case of the compound of formula (viii).)
The group shown by is shown. ]

Here, D -CH ₂ is independently _{-, - CH 2 O -,} - CH 2 OCH 2 -, - Y-NR 15 SO 2 - or -Y-NR ¹⁵ -CO- (where, Y is -CH ₂ -Or

R ¹⁵ represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group), Rf represents a divalent perfluoroalkylene group or a divalent perfluoropolyether group, and z is independently 0 or 1 is there.

  The polymer of component (A) of the present invention is obtained by subjecting a part of the alkenyl group of component (I) to the addition of a hydrosilyl group of component (II), and the remaining alkenyl group of component (I) remains. It is a non-flowable gel polymer.

  In this case, the ratio of the component (I) to the component (II) is such that the amount of hydrosilyl group in the component (II) / the amount of alkenyl group in the component (I) is 0.1 to 0.99, particularly in a molar ratio. It is preferable that it is 0.3-0.8. If this ratio is less than 0.1, the perfluoro compound does not gel, but thickens somewhat, and fluidity remains even if a filler is added. If it exceeds 0.99, it becomes a cured product of the rubber, which makes it difficult to add a filler or does not wind around a roll.

  In addition, it is preferable to use an addition reaction catalyst for addition reaction of (I) component and (II) component, and a platinum group metal compound is desirable as an addition reaction catalyst.

  Here, platinum group metal compounds are generally noble metal compounds and are expensive, and platinum compounds that are relatively easily available are often used.

  The amount of these catalysts used is not particularly limited, and a desired curing rate can be obtained with the amount of catalyst. However, in order to obtain an economical viewpoint or a good cured product, (I), ( II) It is good to set it as the range of 0.1-1,000 ppm (platinum group metal conversion) with respect to the total mass of a component, More preferably, 0.1-500 ppm (same as above).

  The conditions for the above addition reaction can be appropriately selected, and the reaction may be performed at room temperature, but can be performed by heating to 50 to 200 ° C. in order to accelerate the reaction.

  In this case, examples of the reinforcing filler of the component (B) include carbon black, fumed silica, or fumed silica treated with a surface treating agent containing silicon in the molecule. There are two types of composition forms, a liquid rubber composition and a millable rubber composition, both of which are preferably blended with silica powder as a reinforcing filler, and are important in terms of adhesiveness.

  As such silica, in the perfluoropolyether-based fluorine-containing rubber composition, mechanical strength, thermal stability, weather resistance, chemical resistance or flame retardancy is improved, heat shrinkage during curing is reduced, and the composition is cured. Fumed silica, wet silica, pulverized silica and the like can be mentioned for the purpose of reducing the thermal expansion coefficient of the elastic body obtained in this manner, and these may be treated with various surface treatment agents. . Among these, fumed silica is particularly preferable from the viewpoint of improving mechanical strength and dispersion stability of each composition. Further, fumed silica is treated with a silicon compound-based surface treatment such as silane from the viewpoint of improving dispersibility. What was processed with the agent is preferable.

  As a surface treatment agent (hydrophobization treatment agent) of dry process silica called fumed silica, organochlorosilanes such as dimethyldichlorosilane and trimethylchlorosilane which are silicon compounds having hydrolyzable groups, hexamethyldisilazane, etc. And a silazane compound such as hexamethylcyclotrisilazane are preferred.

Further, the specific surface area of the silica by the BET method is preferably 50 m ² / g or more in order to improve the mechanical properties, and further, the thickening at the time of compounding the silica into the composition is increased, and the compounding becomes difficult. Therefore, it is preferable to set it as 300 m < ² > / g or less.

  In order to perform this hydrophobization treatment, the silica fine powder whose surface has been treated with a surface treatment agent is preferably pretreated directly in a powder state, and generally known techniques are used as normal treatment methods. For example, the untreated silica fine powder and the treatment agent are placed in a mechanical kneading apparatus sealed at normal pressure or in a fluidized bed, and if necessary, at room temperature or heat treatment in the presence of an inert gas. In some cases, a catalyst and water for promoting hydrolysis may be used in some cases, and the mixture can be prepared by kneading and drying. The blending amount of the treatment agent may be equal to or more than the amount calculated from the coating area of the treatment agent.

  Furthermore, the bulk density of silica is preferably 30 to 80 g / l. When the bulk density of silica is less than 30 g / l, the viscosity of the composition increases, so that blending may be difficult. When it exceeds 80 g / l, a sufficient reinforcing effect may not be provided.

  The silica content is 1 to 50% by mass in the perfluoropolyether-based fluorine-containing rubber composition. If it is less than 1% by mass, the adhesion may be adversely affected, and the rubber physical properties will be inferior. If it exceeds 50% by mass, the adhesiveness is improved, but the elongation and strength as a rubber material may be insufficient. More preferably, the silica content is 5 to 30% by mass.

  Component (C) is a crosslinking agent. As the crosslinking agent, (C-1) a crosslinking agent capable of addition reaction containing a hydrosilyl group in the molecule or (C-2) a peroxide crosslinking agent is used.

  In this case, as the crosslinking agent of the component (C-1), an organohydrogenpolysiloxane having at least 2, preferably 3 or more hydrosilyl groups in the molecule can be exemplified. As the organohydrogenpolysiloxane, An organohydrogenpolysiloxane that is usually used in addition reaction curable silicone rubber compositions can be used, and in particular, those similar to the above component (II) can be used.

The amount of component (C-1) added is sufficient to react with the remaining alkenyl groups in component (A) and cure component (A). In this case, it is desirable to add this crosslinking agent just before rubber molding in the same manner as the conventional millable rubber composition from the viewpoint of storage stability, but the amount added is the amount of the component (II) used in component (A). It is important to determine the cross-linking material in order to stabilize the rubber properties,
{Amount of hydrosilyl group in component (II) + Amount of hydrosilyl group in component (C)} / Amount of alkenyl group in component (I) is preferably in the range of 0.5 to 5, particularly 0.8 to 2. .

  The component (C-1) can be blended with an addition reaction catalyst such as a platinum group metal compound, if necessary. The addition reaction catalyst used for the production of the component (A) is (A). When it remains in the component, it is not always necessary to add it. The addition amount is a catalyst amount and may be the same as described above.

  On the other hand, as the peroxide crosslinking agent of component (C-2), for example, dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, and the like. From the viewpoint of storage stability and scorch prevention, 2,5-dimethyl-2,5-di-t-butylperoxyhexane is used. Oxyhexane is preferred.

  The peroxide crosslinking agent may be added in an amount sufficient to cure the component (A), but is 0.1 to 5 parts by weight, particularly 0.5 to 100 parts by weight of the component (A). 3 parts by mass is preferred. If the amount is less than 0.1 parts by mass, the crosslinking may be insufficient or the crosslinking may be delayed. If the amount exceeds 5 parts by mass, the physical properties may be adversely affected.

  The fluorine-containing rubber composition has two types of composition forms, a liquid rubber composition and a millable rubber composition. When blending, a millable rubber composition that can be easily mixed by a roll operation is desirable. As described above, as described in JP-A-2000-007835 and JP-A-2001-106893, (A) a molecule having at least two alkenyl groups in the molecule and a divalent perfluoro group in the main chain Polymer obtained by adding a compound capable of addition reaction with an alkenyl group having at least two hydrosilyl groups in a molecule to a part of the alkenyl group of a perfluoro compound having an alkylene structure or a divalent perfluoropolyether structure , (B) reinforcing filler, (C) addition-reactive crosslinking agent or peroxide crosslinking having a hydrosilyl group in the molecule Crosslinkable fluororubber composition characterized by containing a sufficient amount to cure the component (A) are preferred.

  For the same reason, a millable type material is preferably used for blending rather than liquid rubber for the same reason.

  The silicone rubber composition here is described in detail in “Silicone Handbook” (edited by Kunio Ito, published by Nikkan Kogyo Shimbun, August 31, 1990). The modified silicone rubber of Chapter, the fluorosilicone rubber of Chapter 15, and the most preferably used are silicone rubber (Chapter 9) and fluorosilicone rubber (Chapter 15).

In this case, as the silicone rubber composition in which the crosslinking site contains Si—CH═CH ₂ , peroxide crosslinking cured with an organic peroxide, a Si—H group-containing compound, and a platinum group metal catalyst are used. Addition cross-linking is generally used.

As such a silicone rubber composition, for example,
(D) The following average composition formula (I)
(R ¹¹ ) _x SiO _{(4-x) / 2} (I)
(In the formula, R ¹¹ is an unsubstituted or substituted monovalent hydrocarbon group, and x is a number satisfying 1.95 <x <2.05.)
A diorganopolysiloxane represented by the formula: 0.01 to 15 mol% of all R ¹¹ bonded to silicon atoms of the diorganopolysiloxane is a monovalent aliphatic unsaturated hydrocarbon group,
A silicone rubber composition containing (E) a reinforcing filler and (F) a crosslinking agent may be mentioned.

Here, the diorganopolysiloxane of component (D) has the following average composition formula (I)
(R ¹¹ ) _x SiO _{(4-x) / 2} (I)
(In the formula, R ¹¹ is an unsubstituted or substituted monovalent hydrocarbon group, and x is a number satisfying 1.95 <x <2.05.)
In the total R ¹¹ bonded to the silicon atom of the diorganopolysiloxane, 0.01 to 15 mol% is a monovalent aliphatic unsaturated hydrocarbon group. When the content of the aliphatic unsaturated hydrocarbon group is less than 0.01 mol%, a cured product having sufficient tear strength may not be obtained. When the content exceeds 15 mol%, the resulting cured product is obtained. May become inconvenient, and there may be inconveniences such as insufficient tear strength.

Examples of the monovalent aliphatic unsaturated hydrocarbon group include alkenyl groups having 2 to 8 carbon atoms such as a vinyl group and an allyl group. Among them, a vinyl group is preferable. In addition, as R ¹¹ other than the aliphatic unsaturated hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, specifically, for example, An alkyl group such as a methyl group or an ethyl group; an aryl group such as a phenyl group; an aralkyl group such as a benzyl group; a group such as a trifluoropropyl group in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms or the like Among them, a methyl group is preferable among them. The (D) component diorganopolysiloxane may have a hydroxyl group bonded to a silicon atom.

  In the average composition formula (I), x is a number satisfying 1.95 <x <2.05. When x is 1.95 or less, a stable linear polymer is not obtained and is easily gelled. When x is 2.05 or more, it may be difficult to become a high molecular weight polymer.

  In addition, the degree of polymerization of the (D) component diorganopolysiloxane is preferably 1,000 or more, and more preferably 2,000 or more, in order to ensure sufficient mechanical strength of the resulting cured product. It is preferable that it is preferably 3,000 to 10,000.

Specific examples of the (D) component diorganopolysiloxane include the following general formula (II):

(In the formula, c is an integer of 1 or more, d is an integer of 1 or more, and c + d is preferably an integer of 1,000 or more, more preferably an integer of 2,000 or more, and particularly preferably 3). C and d are numerical values such that the proportion of —CH═CH ₂ groups in all organic groups bonded to the silicon atom is 0.01 to 15 mol%. The plurality of R ¹² may be the same or different and are a methyl group, a vinyl group or a hydroxyl group.)
A compound represented by the following general formula (III)

(In the formula, e is an integer of 1 or more, f is an integer of 1 or more, g is an integer of 1 or more, and e + f + g is preferably an integer of 1,000 or more, more preferably an integer of 2,000 or more. And particularly preferably an integer of 3,000 to 10,000, provided that e, f and g have a ratio of —CH═CH ₂ groups in the total organic groups bonded to silicon atoms of 0.01 to (The numerical value is 15 mol%. The plurality of R ¹³ may be the same or different and are a methyl group, a vinyl group, a 3,3,3-trifluoropropyl group or a hydroxyl group.)
A compound represented by the following general formula (IV)

(Wherein e is an integer of 1 or more, f is an integer of 1 or more, g is an integer of 1 or more, e + f + g is preferably an integer of 1,000 or more, more preferably 2,000 or more) And particularly preferably an integer of 3,000 to 10,000, provided that e, f and g have a ratio of —CH═CH ₂ groups in the total organic groups bonded to silicon atoms of 0.00. (The numerical values are from 01 to 15 mol%. The plurality of R ¹⁴ may be the same or different and are a methyl group, a vinyl group, a phenyl group, or a hydroxyl group.)
A compound represented by the general formula (II) is preferable among them.

  The (D) component diorganopolysiloxane can be produced by a known method, for example, a cyclic polysiloxane (siloxane) obtained by (co) hydrolyzing one or more organohalosilanes. Is produced by ring-opening polymerization in the presence of a basic catalyst or an acidic catalyst.

The reinforcing filler of component (E) imparts mechanical strength to the resulting cured product. For example, fumed silica, precipitated silica, fused silica, quartz powder, diatomaceous earth, aluminum silicate, oxidation Examples thereof include titanium, zinc oxide, iron oxide, alumina, calcium carbonate, zinc carbonate, and carbon black. Among them, it is preferable to use a silica to the reinforcement and sufficient, and usually, a specific surface area of 10 m ² / g or more measured by the BET method, is preferably not less than 100 m ² / g used. Particularly preferably, fumed silica and precipitated silica having a specific surface area of 100 to 400 m ² / g are used. In addition, the reinforcing filler of component (E) not only provides mechanical strength to the resulting cured product, but also imparts electrical conductivity, thermal conductivity, and the like.

Examples of the reinforcing filler of the component (E) include chlorosilanes such as (CH ₃ ) ₃ SiCl, (CH ₃ ) ₂ SiCl ₂ , (CH ₃ ) SiCl ₃ ; CH ₂ ═CHSi (OCH ₃ ) ₃ , ( Alkoxysilanes such as CH ₃ ) ₂ Si (OCH ₃ ) ₂ and CH ₃ Si (OCH ₃ ) ₃ ; organosilazanes such as (CH ₃ ) ₃ SiNHSi (CH ₃ ) ₃ ;

(Where h and j are numbers satisfying h> 0, j> 1, 1 <h + j <100.)
Those treated with a surface treatment agent such as silicone oil can be used. A small amount of water may be added to adjust and promote the hydrolyzability of the surface treatment agent.

  (E) The compounding quantity of a component is the range of 5-200 mass parts normally with respect to 100 mass parts of (D) component, Preferably it is the range of 10-100 mass parts. When the blending amount of the component (E) is too small, the processability is insufficient and a sufficient reinforcing effect cannot be obtained, and when it is too large, the workability, mold flowability at the time of processing, etc. are reduced, or the silicone rubber machine In some cases, the target strength may decrease.

  (F) The crosslinking agent of a component should just be a thing which can harden the silicone rubber composition of this invention. As the component (F), a combination of an organohydrogenpolysiloxane and a platinum group metal catalyst or an organic peroxide can be used depending on the curing method.

  As the component (F), an organohydropolypolysiloxane in the case of using a combination of an organohydrogenpolysiloxane and a platinum group metal catalyst is one having at least two Si-H groups in one molecule. The structure used may be any of linear, cyclic or branched structures. The Si—H group may be at the end of the molecular chain or in the middle of the molecular chain. Furthermore, it is usually preferable to use an organohydrogenpolysiloxane having a polymerization degree of 300 or less.

Specifically, the organohydrogenpolysiloxane includes a diorganopolysiloxane terminated with a dimethylhydrogensilyl group; a copolymer comprising dimethylsiloxy units, methylhydrogensiloxy units, and terminal trimethylsiloxy units; Low viscosity fluid comprising dimethylhydrogensiloxy units and SiO ₂ units; 1,3,5,7-tetrahydrogen-1,3,5,7-tetramethylcyclotetrasiloxane; 1-propyl-3,5 , 7-trihydrogen-1,3,5,7-tetramethylcyclotetrasiloxane; 1,5-dihydrogen-3,7-dihexyl-1,3,5,7-tetramethylcyclotetrasiloxane Illustrated. In the organohydrogenpolysiloxane, the Si-H group contained in the organohydrogenpolysiloxane is usually 0.5 to 3.0 mol, preferably 1 per mol of the aliphatic unsaturated hydrocarbon group of the diorganopolysiloxane (D) component. It is preferable to use an amount of 0.0 to 2.0 mol.

  The platinum group metal catalyst is used as a catalyst for the hydrosilylation reaction between the aliphatic unsaturated hydrocarbon group of the (D) component diorganopolysiloxane and the Si-H group in the organohydrogenpolysiloxane. And is usually in the range of 0.1 to 2,000 ppm, preferably 1 to 1,000 ppm (as a platinum group metal), based on the total mass of the organopolysiloxane of component (D) and the organohydrogenpolysiloxane. Used in. Examples of such platinum group metal-based catalysts include finely divided metal platinum catalysts described in US Pat. No. 2,970,150, and chlorides described in US Pat. No. 2,823,218. Platinum acid catalysts, platinum-hydrocarbon complex compounds described in US Pat. No. 3,159,601 and US Pat. No. 3,159,662, US Pat. No. 3,516,946 Platinum-based chloroplatinic acid-olefin complex compounds described in US Pat. No. 3,775,452 and platinum-vinylsiloxane complexes described in US Pat. No. 3,814,780 A catalyst or the like can be used.

  (F) When a combination of organohydrogenpolysiloxane and a platinum group metal catalyst is used as the component and the silicone rubber composition of the present invention is cured by a hydrosilylation reaction, the storage stability at room temperature is good. In order to maintain an appropriate pot life, it is also possible to add reaction control agents such as acetylene alcohols such as methylvinylcyclotetrasiloxane and ethynylcyclohexanol. Curing by the hydrosilylation reaction is performed by heating at a temperature of 60 to 400 ° C. for about 1 minute to 5 hours.

  When an organic peroxide is used as the component (F), the organic peroxide is usually 0.01 to 3 parts by mass, preferably 0.05 to 100 parts by mass of the (D) component diorganopolysiloxane. -1 mass part is mix | blended. As the organic peroxide, those usually used for curing organic peroxide-curing silicone rubber can be used without any particular restriction. Specifically, for example, benzoyl peroxide, bis ( 2,4-dichlorobenzoyl) peroxide, di-t-butyl peroxide, 2,5-dimethyl-di-t-butylperoxyhexane, t-butylperbenzoate, t-butylperoxyisopropyl carbonate, dicumylper Examples include oxides. These may be used alone or in combination of two or more.

  When the organic peroxide is used as the component (F) and the composition of the present invention is cured alone, it is usually heated at a temperature of 100 to 400 ° C. for about 1 minute to 5 hours.

  Moreover, as (F) component, the combination of said organohydrogen polysiloxane and a platinum group metal catalyst and an organic peroxide can also be used together.

  The fluorine-containing rubber composition used in the present invention can be peroxide-crosslinked and addition-crosslinked in the same manner as the silicone rubber composition, and the crosslinking conditions are common.

  As the combination of crosslinking forms for blending, both fluorine-containing rubber composition and silicone rubber composition are peroxide crosslinking and addition crosslinking, so there are four combinations, but the same crosslinking system with common reaction system Must be a combination of

  The fluorine-containing rubber composition and the silicone rubber composition described above are considered to be co-crosslinked because the crosslinking system is the same, and there is no drastic decrease in physical properties due to the blend ratio, and the dumbbell cross section when measuring physical properties When observed, there is no delamination.

  In other combinations with different crosslinking systems, delamination occurs as the physical properties deteriorate, and deburring becomes difficult, for example, when molding is performed.

  From this, the blend ratio of the fluorine-containing rubber composition (a) and the silicone rubber composition (b) is not limited, and may be mixed at an arbitrary ratio according to the purpose. When the content is 5% or more, it is possible to combine the advantages of two types of rubber properties.

  That is, the mixing ratio of the fluorine-containing rubber composition (a) and the silicone rubber composition (b) is (a) :( b) = 95: 5 to 5:95, more preferably 85:15 as the volume ratio. It is preferably 15:85, more preferably 75:25 to 25:75.

  There are no particular restrictions on the blending method, and there are no problems with two rolls generally used in rubber mixing, kneaders, pressure kneaders, Banbury mixers, and the like.

Molding of a rubber composition obtained by blending (b) a silicone rubber composition having the same crosslinking system as the perfluoropolyether-based fluorine-containing rubber composition in which (a) the crosslinking site is Si—CH═CH ₂ in the present invention About conditions, 1 to 30 minutes are preferable at 100-200 degreeC as a primary cure. If it is less than 100 ° C., the curing time becomes long, so that the industrial productivity may be inferior. If it exceeds 200 ° C., there is a risk of scorch generation, so 100 to 200 ° C. is preferable, and further 120 to 170 ° C. Is preferred. The curing time in that case may be appropriately selected as the time for completing the crosslinking reaction.

  A processing method generally used for silicone rubber, such as press molding using a mold, calendar molding, extrusion molding, or the like, may be selected according to the purpose.

  In order to stabilize the physical properties of the rubber composition of the present invention in the same manner as the silicone rubber composition, it is preferable to perform secondary curing by heat treatment at 100 to 230 ° C. for about 1 to 24 hours.

  The secondary cure is less effective at less than 100 ° C and may be thermally decomposed at more than 230 ° C. More preferably, it is suitable at 150 to 200 ° C. for 1 to 20 hours.

  The molded article of the present invention can be used for various applications. In other words, rubber parts for automobiles that require oil resistance, specifically diaphragms for fuel regulators, diaphragms for pulsation dampers, diaphragms for oil pressure switches, diaphragms for EGR, canister valves, power control, etc. Rubber parts for chemical plants, such as valves such as valves, O-rings for quick connectors, O-rings for injectors, or sealing materials such as oil seals and cylinder head gaskets, specifically Diaphragms for pumps, valves, O-rings, hoses, packings, oil seals, rubber parts for ink jet printers, rubber parts for semiconductor production lines, and more specifically equipment that comes into contact with chemicals Die for Rubber parts for analysis and physics and chemistry equipment such as valves that require low friction and wear resistance, such as sealing materials such as frams, valves, O-rings, packings, gaskets, etc. Specifically, diaphragms for valves, valves, seal parts (O-rings, packing, etc.), rubber parts for medical equipment, specifically pumps, valves, joints, etc., tent film materials, sealants, molded parts, extruded parts, coating materials, copier roll materials, electrical use It is useful for moisture-proof coating materials, potting materials for sensors, sealing materials for fuel cells, laminated rubber cloths, etc.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

Composition A used in Examples and Comparative Examples : Perfluoropolyether-based fluorine-containing rubber composition (I): SIFEL5701 (manufactured by Shin-Etsu Chemical Co., Ltd., containing components (A) to (C), addition-crosslinking / millable Type standard composition)
B: Perfluoropolyether-based fluorine-containing rubber composition (II): SIFEL 9700 (manufactured by Shin-Etsu Chemical Co., Ltd., containing components (A) to (C), peroxide crosslinking / millable type standard compounding composition)
C: Silicone rubber composition: KE971 peroxide cross-linking, (D) to (F) component-containing, standard compounding composition (manufactured by Shin-Etsu Chemical Co., Ltd.)
D: Silicone rubber composition: KE971 addition cross-linking, (D) to (F) component contained, standard compounding composition (manufactured by Shin-Etsu Chemical Co., Ltd.)
E: Silicone rubber composition: KE951 peroxide cross-link, containing (D) to (F) components, standard blend composition (manufactured by Shin-Etsu Chemical Co., Ltd.)
F: Silicone rubber composition: KE951 addition crosslinking, (D) to (F) component-containing, standard blend composition (manufactured by Shin-Etsu Chemical Co., Ltd.)

Mixing of composition and molding conditions (1) The rubber composition was mixed with two rolls for 3.5 inch rubber at the specified compounding ratios shown in Tables 1 to 4 below. The roll workability of the final composition at the time of roll mixing was confirmed by the following method.
(2) The composition mixed as described above is crosslinked with a 75-ton press for rubber under conditions of 150 ° C. and 10 minutes, and then post-cured at 200 ° C. for 4 hours to form a linear shape with the sheet molded product. A 5 mm O-ring was made.
(3) The sheet molded product was punched into a dumbbell shape, various physical properties were confirmed, and the fracture surface was observed to confirm the presence or absence of delamination by the following method. The O-ring was checked for burr removal by the following method, and the compression set was measured at 200 ° C. for 72 hours and 25% compression.
(4) The sheet piece was immersed in toluene at 23 ° C. for 72 hours, and toluene swelling (% by volume) was measured according to the method of JIS K6258.

[Roll workability evaluation method]
Roll workability was evaluated according to the following criteria.
○: Good workability without sticking to the roll.
X: There is adhesion to the roll, and it takes time to work.

[Method for evaluating delamination]
The cross section of the dumbbell used for the physical property measurement was observed (as shown in the photographs in FIGS. 1 to 4) and judged according to the following criteria.
○: There is no abnormality on the rubber fracture surface, and there is no delamination.
X: Breakage is not constant and delamination occurs.

[Evaluation method for burr removal]
Deburring conditions were evaluated according to the following criteria.
○: The burr is easily removed and a good O-ring is obtained.
X: Burrs are not removed well due to the delamination phenomenon, and it is necessary to use scissors for finishing.

[Examples 1 to 3 and Comparative Examples 1 and 2]
Table 1 shows the characteristics of a composition obtained by blending an addition-crosslinking type perfluoropolyether-based fluororubber composition A having a hardness 70 of the cured product and a silicone rubber composition D having the same hardness and crosslinking type as the cured product.
A cured product having no delamination could be obtained without extremely deteriorating the physical properties depending on the blending ratio. It can be seen that by blending, the fluorine-containing rubber composition has improved roll workability and compression set, and the silicone rubber has improved toluene swellability.

[Examples 4 to 6 and Comparative Examples 3 and 4]
Table 2 shows the characteristics of a composition obtained by blending a peroxide cross-linking type perfluoropolyether-based fluororubber composition B having a hardness of 70 and a cured silicone rubber composition C having the same hardness and cross-linking type.
Similar to the addition crosslinking type, a cured product without delamination could be obtained without a drastic decrease in physical properties depending on the blending ratio. It can be seen that blending has the same effect as addition crosslinking.

[Examples 7 and 8 and Comparative Examples 5 and 6]
Blending with rubber materials with different hardness was also performed. Results of blending silicone rubber addition cross-linking composition F having a hardness of 50 and peroxide cross-linking compounding composition E with perfluoropolyether-based fluororubber compositions A and B having a hardness of 70 of the same cross-linking system. Is shown in Table 3. When different materials are blended and cannot be co-crosslinked, delamination is likely to occur in a combination having greatly different physical properties such as a difference in hardness. However, it was confirmed that no delamination was observed in the cured product of the present invention. In this example and comparative example, toluene swelling and compression set were not measured.

[Comparative Examples 7 to 9]
The same confirmation was made with rubber materials having different crosslinking systems. Table 4 shows the results of blending the cured silicone rubber peroxide cross-linking composition E having a hardness of 50 and the perfluoropolyether fluororubber composition A having a hardness of 70 of the addition-cured cured product. Delamination was confirmed at any blending ratio. Since delamination was observed, toluene swelling and compression set were not measured.

This is an example of a photograph of a cross section of a dumbbell used for measuring physical properties. The rubber fracture surface is not abnormal and has no delamination. This is another example of a photograph of a cross section of a dumbbell used for measuring physical properties. The rubber fracture surface has no abnormality and no delamination. An example of a photograph of a cross section of a dumbbell used for measuring physical properties, in which the fracture is not constant and delamination occurs. Another example of a photograph of a cross-section of a dumbbell used for measuring physical properties, in which the fracture was not constant and delamination occurred.

Claims (7)

(A) obtained by mixing a perfluoropolyether-based fluorine-containing rubber composition having a crosslinking site of Si—CH═CH ₂ and (b) a silicone rubber composition having the same crosslinking system as this fluorine-containing rubber composition. Rubber composition.   2. The rubber according to claim 1, wherein the cross-linking system is a peroxide cross-linking type, and the perfluorinated polyether-based fluororubber composition and the silicone rubber composition of the peroxide cross-linking type are mixed. Composition.   2. The rubber composition according to claim 1, wherein the crosslinking system is an addition crosslinking type, and the addition crosslinking type perfluoropolyether-based fluorine-containing rubber composition and a silicone rubber composition are mixed. . The perfluoropolyether-based fluorine-containing rubber composition (a) is
(A) a part of the alkenyl group of the perfluoro compound having at least two alkenyl groups in the molecule and having a divalent perfluoroalkylene structure or a divalent perfluoropolyether structure in the main chain; A polymer formed by adding a compound capable of addition reaction with an alkenyl group having at least two hydrosilyl groups in the molecule,
(B) Crosslinkability comprising a reinforcing filler, and (C) a crosslinking agent having a hydrosilyl group in the molecule or a peroxide crosslinking agent in an amount sufficient to cure the component (A). The rubber composition according to any one of claims 1 to 3, wherein the rubber composition is a fluororubber composition. Said silicone rubber composition is
(D) The following average composition formula (I)
(R ¹¹ ) _x SiO _{(4-x) / 2} (I)
(In the formula, R ¹¹ is an unsubstituted or substituted monovalent hydrocarbon group, and x is a number satisfying 1.95 <x <2.05.)
A diorganopolysiloxane represented by the formula: 0.01 to 15 mol% of all R ¹¹ bonded to silicon atoms of the diorganopolysiloxane is a monovalent aliphatic unsaturated hydrocarbon group,
The rubber composition according to any one of claims 1 to 4, which is a silicone rubber composition comprising (E) a reinforcing filler and (F) a crosslinking agent.   A rubber molded article obtained by molding and curing the rubber composition according to any one of claims 1 to 5.   The rubber molded product according to claim 6, wherein the molded product is a seal material, an O-ring, a diaphragm, a hose, a cap, or a valve material.