JP5110280B2 - Curable fluoropolyether rubber composition - Google Patents

Description

  The present invention provides a cured product having excellent water repellency, oil repellency, low temperature, chemical resistance, solvent resistance, heat resistance and improved compression set characteristics, and is suitably used as an O-ring or the like. The present invention relates to a curable fluoropolyether rubber composition.

  Linear fluoropolyether compounds having at least two alkenyl groups in the molecule and a perfluoroalkyl ether structure in the main chain are used for various applications because of the properties of the perfluoroalkyl ether structure. ing. In this case, silica-based fillers such as dry-process silica called fumed silica and wet-process silica called precipitated silica used for reinforcement of silicone rubber and the like are used as curable fluoropolyether-based fillers. It has been found that the mechanical properties of the obtained cured product can be drastically improved by blending with rubber. This makes it possible to obtain a fluoropolyether rubber composition with a good balance of properties such as heat resistance, chemical resistance, solvent resistance, water repellency, oil repellency, weather resistance, etc. It has sufficient performance. (See Patent Documents 1 to 3)

  We have also proposed a method for modifying a naturally hydrophilic surface such as silica to a water-repellent surface by treating it with a silicone-based composition. Particularly, polysiloxane or polysilazane containing a perfluoroalkyl group is excellent in water repellency. It is also well known. (See Patent Documents 4 to 6)

  In addition, it is known that the mechanical properties of the obtained cured product can be improved by blending silica whose surface such as silica has been submerged with fluorosilicone or the like as a reinforcing agent such as silicone rubber. (See Patent Documents 7 and 8)

  However, although the conventional fluoropolyether rubber composition is sufficient in performance for most applications, molding applications such as O-rings are required to have a lower compression set. Improvement of permanent distortion characteristics has been a problem.

JP 2001-192546 A JP 2000-248166 A JP 2002-20615 JP-A-3-290437 JP-A-6-256756 JP-A-9-59605 JP 6-92502 JP-A-7-316456

  The present invention has been made in view of the above circumstances, and is excellent in water repellency, oil repellency, low temperature properties, chemical resistance, solvent resistance, heat resistance and the like, and has compression set characteristics, particularly compression set in an aqueous solution. An object of the present invention is to provide a curable fluoropolyether rubber composition having excellent strain characteristics.

（ｏ，ｍ又はｐ−ジメチルシリルフェニレン基）

（ｏ，ｍ又はｐ−ジメチルシリルフェニレン基）で表される基である。Ｒｆ ¹ は二価のパーフルオロポリエーテル構造である。Ｑは炭素数１〜１５の二価の炭化水素基であり、エーテル結合を含んでいてもよい。）、ｐは独立に０又は１である。］ The present inventors have made intensive studies to achieve the above object,
The component (a) has at least two alkenyl groups in the molecule, and -C _a F _2a O- in the main chain (wherein, a in each unit is an integer of 1 to 6 independently) the weight average molecular weight with a divalent perfluoroalkyl ether structure comprising recurring units 5,000～10 ten thousand linear perfluoropolyether is compound 100 parts by weight (b) BET specific surface area of 50 m ² / g or more at a 10 to 40 parts by mass of a silica-based filler having a surface hydrophobized with a fluorosilazane compound having a perfluoroalkyl group having 3 or more carbon atoms and a hydrolyzable group represented by the following general formula (5)
[(RfQ) _a Si (R ¹ ) _b (NR ² ) _{4-ab / 2} ] _l (5)
[Wherein R ^{1 s} may be the same or different and each represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group; R ² may be the same or different and represent a hydrogen atom or an alkyl group] Rf, which may be the same or different, is a perfluoroalkyl group having 3 to 20 carbon atoms; Q is a divalent organic group having 2 to 5 carbon atoms; In the structural unit, a is an integer of 1 to 3, b is an integer of 0 to 2, provided that a + b is an integer of 1 to 3, and l is an integer of 2 or more. ]
(C) The hydrosilylation reaction catalyst is 0.1 to 1,000 ppm in terms of platinum group metal based on the total amount of the composition.
(D) The fluorine-containing organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule is a ratio of SiH group in component (d) to alkenyl group in component (a) (SiH group / alkenyl group). ) Is a curable fluoropolyether rubber composition containing an amount of 0.4 to 5.0, and is excellent in water repellency, oil repellency, low temperature, chemical resistance, solvent resistance, heat resistance, etc. In addition, the present inventors have found that a cured product having excellent compression set characteristics can be obtained, and have reached the present invention.
Accordingly, the present invention provides the following curable fluoropolyether rubber composition.
[1]
The component (a) has at least two alkenyl groups in the molecule, and -C _a F _2a O- in the main chain (wherein, a in each unit is an integer of 1 to 6 independently) 100 parts by mass of a linear perfluoropolyether compound having a divalent perfluoroalkyl ether structure containing a repeating unit of
(B) The surface is hydrophobized with a fluorosilazane compound having a BET specific surface area of 50 m ² / g or more and a perfluoroalkyl group having 3 or more carbon atoms and a hydrolyzable group represented by the following general formula (5). 10 to 40 parts by mass of the silica-based filler
[(RfQ) _a Si (R ¹ ) _b (NR ² ) _{4-ab / 2} ] _l (5)
[Wherein R ^{1 s} may be the same or different and each represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group; R ² may be the same or different and represent a hydrogen atom or an alkyl group] Rf, which may be the same or different, is a perfluoroalkyl group having 3 to 20 carbon atoms; Q is a divalent organic group having 2 to 5 carbon atoms; In the structural unit, a is an integer of 1 to 3, b is an integer of 0 to 2, provided that a + b is an integer of 1 to 3, and l is an integer of 2 or more. ]
(C) The hydrosilylation reaction catalyst is 0.1 to 1,000 ppm in terms of platinum group metal based on the total amount of the composition.
(D) The fluorine-containing organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule is a ratio of SiH group in component (d) to alkenyl group in component (a) (SiH group / alkenyl group). ) Is 0.4 to 5.0
A curable fluoropolyether rubber composition comprising:
[2]
The curable fluoropolyether rubber composition according to [1], wherein the component (a) is a polyfluorodialkenyl compound represented by the following general formula.
_{CH 2 = CH- (X) p} -Rf 1 - (X ') p -CH = CH 2 (3)
_{CH 2 = CH- (X) p} -Q-Rf 1 -Q- (X ') p -CH = CH 2 (4)
[-CH ₂ wherein, X is independently _{-, - CH 2 O -,} - CH 2 OCH 2 - or -Y-NR ¹ -CO- (where, Y is -CH ₂ - or the following structural formula (Z) And R ¹ is a hydrogen atom, a methyl group, a phenyl group or an allyl group.) And X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO. —NR ² —Y′— (where Y ′ is —CH ₂ — or a group represented by the following structural formula (Z ′), R ² is a hydrogen atom, a methyl group, a phenyl group, or an allyl group;

(O, m or p-dimethylsilylphenylene group)

A group represented by (o, m or p-dimethylsilylphenylene group). Rf ¹ is a divalent perfluoropolyether structure. Q is a C1-C15 divalent hydrocarbon group and may contain an ether bond. ), P is independently 0 or 1. ]

According to the curable fluoropolyether rubber composition of the present invention, a cured product having excellent compression set characteristics in various aqueous solutions, particularly mixed aqueous solutions with ethylene glycol, can be used suitably as an O-ring or the like. It is possible to provide a curable fluoropolyether rubber composition that can be used. Moreover, the composition of the present invention is excellent in the water repellency, oil repellency, low temperature, chemical resistance, solvent resistance, and heat resistance inherent to the fluoropolyether rubber.

  Accordingly, the present invention provides a curable fluoropolyether rubber composition comprising the above components (a) to (d).

(A) Component linear polyether compound (a) Component linear fluoropolyether compound has at least two alkenyl groups in the molecule and a divalent perfluoroalkyl ether in the main chain It has a structure and has a weight average molecular weight of 5,000 to 100,000, and is used as a base polymer of the composition.

Here, the perfluoroalkyl ether structure includes a number of repeating units of —C _a F _2a O— (wherein a in each unit is an integer of 1 to 6). Examples thereof include those represented by the general formula (2).
(C _a F _2a O) _q (2)
(In the formula, q is an integer of 20 to 600, preferably 30 to 400, more preferably 30 to 200.)

Repeating units _-C n _F 2n as O- is represented by the formula (2), for example, unit of the following, and the like. In addition, the said perfluoroalkyl ether structure may be comprised by 1 type of these repeating units individually, and the combination of 2 or more types may be sufficient as it.
—CF ₂ O—
-CF ₂ CF ₂ O-
-CF ₂ CF ₂ CF ₂ O-
-CF (CF ₃ ) CF ₂ O-
_{-CF 2 CF 2 CF 2 CF 2} O-
_{-CF 2 CF 2 CF 2 CF 2} CF 2 CF 2 O-
-C _{(CF 3)} 2 O-
Of these, the following units are particularly preferred.
—CF ₂ O—
-CF ₂ CF ₂ O-
-CF ₂ CF ₂ CF ₂ O-
-CF (CF ₃ ) CF ₂ O-

As the alkenyl group in the linear perfluoropolyether compound of component (a), those having 2 to 8 carbon atoms, particularly 2 to 6 and having a CH ₂ ═CH— structure at the terminal are preferable. A group having a CH ₂ ═CH— structure at the terminal such as a group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group or a hexenyl group, particularly a vinyl group or an allyl group is preferred.

Examples of the component (a) include polyfluorodialkenyl compounds represented by the following general formula.
_{CH 2 = CH- (X) p} -Rf 1 - (X ') p -CH = CH 2 (3)
_{CH 2 = CH- (X) p} -Q-Rf 1 -Q- (X ') p -CH = CH 2 (4)
_[-CH 2 wherein, X is independently _{-, - CH 2 O -,} - CH 2 OCH 2 - or ^-Y-NR 1 -CO- (where, Y is -CH ₂ - or the following structural formula (Z) And R ¹ is a hydrogen atom, a methyl group, a phenyl group or an allyl group.) And X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO. —NR ² —Y′— (where Y ′ is —CH ₂ — or a group represented by the following structural formula (Z ′), R ² is a hydrogen atom, a methyl group, a phenyl group, or an allyl group;

（ｏ，ｍ又はｐ−ジメチルシリルフェニレン基）

(O, m or p-dimethylsilylphenylene group)

（ｏ，ｍ又はｐ−ジメチルシリルフェニレン基）で表される基である。Ｒｆ^１は二価のパーフルオロポリエーテル構造であり、上記式（２）、即ち（Ｃ_ａＦ_２ａＯ）_ｑで示される繰り返し単位を含むものが好ましい。Ｑは炭素数１〜１５の二価の炭化水素基であり、エーテル結合を含んでいてもよく、具体的にはアルキレン基、エーテル結合を含んでいてもよいアルキレン基である。）、ｐは独立に０又は１である。］

A group represented by (o, m or p-dimethylsilylphenylene group). Rf ¹ is a divalent perfluoropolyether structure, and preferably includes a repeating unit represented by the above formula (2), that is, (C _a F _2a O) _q . Q is a C1-C15 divalent hydrocarbon group which may contain an ether bond, specifically an alkylene group or an alkylene group which may contain an ether bond. ), P is independently 0 or 1. ]

  As such a linear perfluoropolyether compound of component (a), those represented by the following general formula (1) are particularly suitable.

［式中、Ｘ、Ｘ’及びｐは前記と同じであり、ｒは２〜６の整数、ｍ、ｎはそれぞれ０〜６００の整数であり、更にｍとｎの和が２０〜６００である。］

[Wherein, X, X ′ and p are the same as above, r is an integer of 2 to 6, m and n are each an integer of 0 to 600, and the sum of m and n is 20 to 600] . ]

  The linear perfluoropolyether compound of the above formula (1) has a polystyrene-reduced weight average molecular weight of 5,000 to 100,000, particularly 5,000 to 50,000, as determined by gel permeation chromatography (GPC). Is desirable. If the weight average molecular weight is less than 5,000, the required chemical resistance may not be satisfied, which is not preferable. If the weight average molecular weight exceeds 100,000, there is a problem in compatibility with other components. Since it may be, it is not preferable.

  Specific examples of the linear perfluoropolyether compound represented by the general formula (1) include those represented by the following formula.

（式中、ｍ及びｎはそれぞれ０〜６００，ｍ＋ｎ＝２０〜６００を満足する整数を示す。）

(In the formula, m and n are integers satisfying 0 to 600 and m + n = 20 to 600, respectively.)

Furthermore, in the present invention, in order to adjust the linear perfluoropolyether compound of the above formula (1) to a desired weight average molecular weight according to the purpose, It is also possible to use, as a component (a), a product obtained by subjecting an organosilicon compound containing two SiH groups to a hydrosilylation reaction in the usual manner and conditions and extending the chain length.
These linear fluoropolyether compounds can be used singly or in combination of two or more.

(B) A silica-based filler (b) component whose surface is hydrophobized by a substituent containing a perfluoroalkyl group having a BET specific surface area of 50 m ² / g or more and a carbon number of 3 or more is curable. This silica filler is used to reinforce fluoropolyether rubber compositions and improve compression set properties. This silica filler is called dry silica, fumed silica, and precipitated silica. Any of the wet process silicas may be used, and in order to improve mechanical properties, the BET specific surface area (nitrogen adsorption method) needs to be in the form of particles having at least 50 m ² / g.

The silica-based filler is a compound containing a perfluoroalkyl group and a hydrolyzable group or a partially hydrolyzable hydroxyl group bonded to a silicon atom on the silica surface in order to improve compression set characteristics. It can be obtained by treating with an organosilicon compound comprising a reactant.

The surface treatment agent capable of covering the surface with a perfluoroalkyl group is not particularly limited as long as it is a silicon compound having a perfluoroalkyl group and a hydrolyzable group. (5),
[(RfQ) _a Si (R ¹ ) _b (NR ² ) _4-ab-2 ] _l (5)
[Wherein R ^{1 s} may be the same or different and each represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group; R ² may be the same or different and represent a hydrogen atom or an alkyl group] Rf, which may be the same or different, is a perfluoroalkyl group having 3 to 20 carbon atoms; Q is a divalent organic group having 2 to 5 carbon atoms; In the structural unit, a is an integer of 1 to 3, b is an integer of 0 to 2, provided that a + b is an integer of 1 to 3, and l is an integer of 2 or more. The fluorine-containing silazane compounds shown are most preferred.

In the formula (5), each R ¹ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group. Examples of the unsubstituted or substituted monovalent hydrocarbon group include methyl, ethyl, propyl, Alkyl groups such as butyl and hexyl groups, alkenyl groups such as vinyl and allyl groups, aryl groups such as phenyl and tolyl groups, cycloalkyl groups such as cyclohexyl groups, or hydrogen atoms bonded to two or less carbon atoms of these groups Is a halogenated hydrocarbon group in which a part or all of them are substituted with a halogen atom, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, such as 3,3,3-tri fluoropropyl _group, a CF ₃ CF _{2 CH} 2 _CH 2 group or the like; ^{R 2} is a hydrogen atom or an alkyl group, e.g., methyl, ethyl, propyl, butyl, der hexyl group , Is preferably a hydrogen atom; Rf is, for example, the _{formula: C c F 2c + 1 -} ( wherein, c is an integer of 3 to 20) be a perfluoroalkyl group represented by; Q is 2 carbon atoms To 5 divalent organic groups, for example, an alkylene group such as a formula: —CH ₂ CH ₂ — group, —CH ₂ CH ₂ CH ₂ — group, a formula: —CH ₂ OCH ₂ CH ₂ CH ₂ — group, etc. An oxygen-substituted alkylene group, an alkylamide group such as —CONHCH ₂ CH ₂ CH ₂ —, and the like.

  a and b are each the above integers, provided that a + b is the above integer and may be the same or different in each structural unit. Each l is an integer of 2 or more, and preferably l ≦ 3. If the value of l is too larger than the above range, the viscosity of the silazane compound increases and it becomes difficult to uniformly treat the surface of the silica filler, which is not preferable.

Synthesis of fluorinated silazane compound: The fluorinated silazane compound represented by the general formula (5) is, for example, represented by the general formula (6)
(RfQ) _a Si (R ¹ ) _b X _4-ab (6)
[Wherein R ¹ , Rf, Q, a, b and a + b are as defined above; X is a halogen atom, for example, chlorine or bromine], and the organosilane is selected from ammonia and a primary amine It can manufacture by making it react with at least 1 sort (s).

  Examples of the fluorine-containing silazane compound thus obtained include the following.

  The silica fine powder to be treated using this surface treatment agent may be treated directly with a fluorinated silazane compound in a powder state in advance, or may be treated by diluting the fluorinated silazane compound in an appropriate solvent. preferable. As such a dilution solvent, hexane, toluene, alcohol (methanol, ethanol, propanol, etc.), acetone, etc. (in some cases, water, etc.) are used.

As the surface treatment method, generally known techniques can be employed. 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. Depending on the condition, the mixture is mixed 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, and the catalyst can be prepared by kneading and drying.
Examples of the catalyst added for the purpose of promoting the hydrolysis / condensation reaction of the fluorine-containing silazane compound include organic tin compounds such as dibutyltin dimethoxide and dibutyltin dilaurate, and organic titanium compounds such as tetra-n-butyl titanate. Organic acids such as acetic acid and methanesulfonic acid, and inorganic acids such as hydrochloric acid and sulfuric acid. Of these, acetic acid, tetra-n-butyl titanate, and dibutyltin dilaurate are desirable.

  The compounding amount of the fluorine-containing silazane compound surface treatment agent may be equal to or more than the amount calculated from the coating area of the untreated silica fine powder with respect to the treatment agent, but is usually 100 parts by mass of the untreated silica fine powder. The fluorine-containing silazane compound may be 3 to 25 parts by mass, preferably 10 to 20 parts by mass.

The number of carbon atoms of the perfluoroalkyl group of the surface treatment agent is preferably a C ₃ F ₇ CH ₂ CH ₂ Si— group or more. If the number of carbon atoms is smaller than that of the C ₃ F ₇ CH ₂ CH ₂ Si— group, the polarity of the fluorine-modified group becomes too high, the effect of improving the compression set characteristics is not recognized, and the viscosity at the time of preparing the base increases rapidly there's a possibility that.

The modified amount of the treated silica can be roughly understood by using ²⁹ Si CP / MAS NMR. However, a TMS (tetramethylsilane) standard has a siloxane bond located near a chemical shift value of −90 ppm. A trialkyl located near 15 ppm relative to the sum of the amount of Si (Q2 unit) on the filler surface having two and the amount of Si (Q3 unit) on the filler surface having three siloxane bonds located near -100 ppm. The ratio of the amount of Si (M unit) in the siloxy unit is preferably 0.3 to 0.9, more preferably 0.7 to 0.8, from the viewpoint that the effect of silylation can be easily obtained.

The compounding quantity of this silica type filler is 10-40 mass parts with respect to 100 mass parts of (a) component, More preferably, it is 15-30 mass parts. When the amount is less than 10 parts by mass, the mechanical strength is not improved because the amount is too small. When the amount exceeds 40 parts by mass, the increase in viscosity is large and blending is difficult.

(C) Hydrosilylation reaction catalyst As the hydrosilylation reaction catalyst of component (c), transition metals, for example, platinum group metals such as Pt, Rh, Pd, and compounds of these transition metals are preferably used. In the present invention, since these compounds are generally precious metal compounds and are expensive, platinum compounds that are relatively easily available are preferably used. Specific examples of the platinum compound include chloroplatinic acid or a complex of chloroplatinic acid and olefin such as ethylene, a complex of alcohol or vinylsiloxane, or platinum supported on a carrier such as silica, alumina or carbon. However, it is not limited to these.

As platinum group metal compounds other than platinum compounds, rhodium, ruthenium, iridium, palladium compounds and the like are known. For example, RhCl (PPh ₃ ) ₃ , RhCl (CO) (PPh ₃ ) ₂ , RhC1 (C ₂ H ₄ ) ₂ , Ru ₃ (CO) ₁₂ , IrCl (CO) (PPh ₃ ) ₂ , Pd (PPh ₃ ) ₄ (Ph represents a phenyl group). 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, the total amount of the composition is used. It is good to set it as the range of about 0.1-1,000 ppm (platinum group metal conversion), More preferably about 0.1-500 ppm (same as the above).

(D) Fluorine-containing organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule. Next, (d) component fluorinated organosilicon compound is the above-mentioned component (a) crosslinking agent, It acts as a chain extender. In consideration of compatibility with the component (a), dispersibility, and uniformity after curing, one or more monovalent perfluoroalkylene group, monovalent perfluorooxyalkyl group, divalent The organic silicon compound is particularly limited as long as it has a perfluoroalkylene group or a divalent perfluorooxyalkylene group and has at least 2, preferably 3 or more hydrogen atoms bonded to a silicon atom in one molecule. It is not something.

Examples of the perfluoroalkyl group, perfluorooxyalkyl group, perfluoroalkylene group, and perfluorooxyalkylene group include groups represented by the following general formula.
C _g F _{2g + 1} −
(In the formula, g is an integer of 1 to 20, preferably 2 to 10.)
−C _g F _2g −
(In the formula, g is an integer of 1 to 20, preferably 2 to 10.)

（式中、ｆは２〜２００、好ましくは２〜１００、ｈは１〜３の整数である。）

(In the formula, f is 2 to 200, preferably 2 to 100, and h is an integer of 1 to 3.)

（式中、ｉ及びｊは１以上の整数、ｉ＋ｊの平均は２〜２００、好ましくは２〜１００である。）

−（ＣＦ_２Ｏ）_ｄ−（ＣＦ_２ＣＦ_２Ｏ）_ｅ−ＣＦ_２−
（但し、ｄ及びｅはそれぞれ１〜５０の整数である。）

(In the formula, i and j are integers of 1 or more, and the average of i + j is 2 to 200, preferably 2 to 100.)

_{- (CF 2 O) d -} (CF 2 CF 2 O) e -CF 2 -
(However, d and e are each an integer of 1 to 50.)

These perfluoro (oxy) alkyl groups and perfluoro (oxy) alkylene groups may be directly bonded to the silicon atom, but may be bonded to the silicon atom via a divalent linking group. Here, the divalent linking group may be an alkylene group, an arylene group, or a combination thereof, or an ether bond oxygen atom, an amide bond, a carbonyl bond, or the like interposed therebetween. The thing of number 2-12 is preferable and the following group etc. are mentioned.
—CH ₂ CH ₂ —
-CH ₂ CH ₂ CH ₂ -
_{-CH 2 CH 2 CH 2 OCH 2} -
—CH ₂ CH ₂ CH ₂ —NH—CO—
—CH ₂ CH ₂ CH ₂ —N (Ph) —CO— (where Ph is a phenyl group)
_{-CH 2 CH 2 CH 2 -N (} CH 3) -CO-
—CH ₂ CH ₂ CH ₂ —O—CO—
And those having 2 to 12 carbon atoms.

  The monovalent or divalent fluorine-containing substituent in the organosilicon compound of component (d), that is, a monovalent containing a perfluoroalkyl group, a perfluorooxyalkyl group, a perfluorooxyalkylene group or a perfluoroalkylene group. Examples of the monovalent substituent bonded to the silicon atom other than the organic group include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, an octyl group, and a decyl group; a phenyl group, Aryl groups such as tolyl group and naphthyl group; aralkyl groups such as benzyl group and phenylethyl group: or a part of hydrogen atoms of these groups are substituted by chlorine atom, cyano group, etc., for example, chloromethyl group, chloropropyl group And an unsubstituted or substituted hydrocarbon group having 1 to 20 carbon atoms such as a cyanoethyl group.

  The fluorine-containing organosilicon compound as component (d) may be cyclic or chain-like, and further may be a three-dimensional network. Further, the number of silicon atoms in the molecule in the fluorine-containing organosilicon compound is not particularly limited, but usually 2 to 60, particularly about 3 to 30 is preferable.

  Examples of such organosilicon compounds include the following compounds, and these compounds may be used alone or in combination of two or more. In the following formulae, Me represents a methyl group, and Ph represents a phenyl group.

（ｎ＝１〜５０、ｍ＝１〜５０、ｎ＋ｍ＝２〜５０）

(N = 1-50, m = 1-50, n + m = 2-50)

  The blending amount of component (d) is usually that of hydrosilyl groups in component (d), that is, SiH groups, relative to 1 mol of alkenyl groups such as vinyl group, allyl group, cycloalkenyl group and the like contained in component (a). The total amount is preferably 0.4 to 5.0 mol, more preferably 0.8 to 3.0 mol. If the blending amount of the component (d) is too small, the degree of crosslinking may be insufficient and the strength of the cured product may be insufficient. Even if the amount is too large, chain length extension takes precedence, curing becomes insufficient or foams, Heat resistance, compression set characteristics, etc. may be deteriorated. In addition, the compounding quantity with respect to (a) component of this (d) component can also be made into the range of 0.1-50 mass parts with respect to 100 mass parts of (a) component normally. Moreover, this (d) component may be used individually by 1 type, and may use 2 or more types together.

Other components In addition to the components (a) to (d), various conventionally known additives can be blended in the composition of the present invention as long as the effects of the present invention are not impaired. Specific examples of such components include 1-ethyl-1-hydroxycyclohexane, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 3-methyl-1. -Control agents for hydrosilylation reaction catalysts such as acetylene alcohols such as pentyn-3-ol and phenylbutynol, 3-methyl-3-penten-1-in, and 3,5-dimethyl-3-hexen-1-in, Examples thereof include pigments such as iron oxide, cerium oxide, and carbon black, colorants, dyes, antioxidants, oil-like compounds in which some or all are fluorine-modified, and the like. In addition, the addition amount of these arbitrary components can be made into a normal amount in the range which does not inhibit the effect of this invention.

Method of Use The composition of the present invention may be configured as a so-called one-component type in which all the essential components (A) to (D) are handled as one composition depending on the application, or, for example, ( A), (C) and (D) components are used as one composition, and (A), (B) and (D) components are used as the other composition. You may mix.

It is also possible to use the composition after dissolving and diluting it. Examples of such a solvent, (A) is preferably one capable of dissolving the components, for example, _{C 4 F 10, C 8 F} 18, C 4 F 9 OCH 3, C 4 F 9 OC 2 H 5, 2-n- Examples include fluorinated solvents such as nonafluorobutyl-tetrafluorofuran, tris (n-nonafluorobutyl) amine, metaxylene hexafluoride, paraxylene hexafluoride, benzotrifluoride and the like.

  The composition of the present invention can be easily cured by standing at room temperature or heating, but is usually thermally in the range of room temperature (for example, 5-35 ° C.) to 200 ° C., 1 minute to 24 hours. It is preferable that the conductive rubber is cured. By such curing, a conductive rubber having excellent characteristics can be obtained.

The density of the cured product of the composition of the present invention thus obtained is preferably 4.0 g / cm ³ or less, particularly preferably 3.0 g / cm ³ or less.

Applications The composition of the present invention can be used for various applications. That is, since the fluorine content is high, it has excellent solvent resistance and chemical resistance, and also has low moisture permeability and low surface energy, so it has excellent releasability and water repellency, and requires oil resistance. Rubber parts for automobiles, specifically diaphragms for fuel regulators, diaphragms for pulsation dampers, diaphragms for oil pressure switches, diaphragms for EGR, valves for canisters, valves for power control, quick connectors O-rings such as O-rings for injectors, O-rings for injectors, or rubber components for chemical plants such as seals such as oil seals and gaskets for cylinder heads, specifically pump diaphragms, valves, O- Rings, hoses, packings, oil seals, gas Low friction such as sealing materials for ink jet printers, rubber parts for semiconductor production lines, specifically diaphragms for valves, O-rings, packings, gaskets, etc. Rubber parts for analysis, physics and chemistry equipment, such as valves that require wear resistance, specifically diaphragms for pumps, 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 moisture-proof coating materials, sensor potting materials, fuel cell sealing materials, laminated rubber cloths, etc. Useful for.

  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. In addition, a viscosity is a value in 25 degreeC and Me represents a methyl group by the following formula.

[Example 1]
Following formula (9)

で表されるポリマー（粘度５，５００ｍｍ^２／ｓ、重量平均分子量１５，７００、ビニル基量０．０１２モル／１００ｇ）１００質量部に、未処理シリカ系填剤（品名 ＡＥＲＯＳＩＬ３００：日本アエロジル（株）社製商品名）を、Ｃ_４Ｆ_９―なるパーフルオロアルキル基を含有する置換基で処理した処理シリカＡ（比表面積１８２ｍ^２／ｇ）を２０質量部の配合比でプラネタリーミキサーにて配合を行った後、１時間混練りを行った。混練り後１５０℃で１時間混合熱処理し、３本ロールにて分散処理してベースの製造を行った。

100 parts by mass of a polymer represented by the formula (viscosity 5,500 mm ² / s, weight average molecular weight 15,700, vinyl group content 0.012 mol / 100 g), untreated silica filler (product name AEROSIL300: Nippon Aerosil Co., Ltd.) ) (Trade name manufactured by company) treated with a substituent containing a perfluoroalkyl group consisting of C ₄ F ₉ — and treated silica A (specific surface area 182 m ² / g) at a blending ratio of 20 parts by mass with a planetary mixer After blending, kneading was performed for 1 hour. After kneading, the mixture was heat-treated at 150 ° C. for 1 hour, and dispersed by three rolls to produce a base.

Preparation method of treated silica A:
70 g of the fluorine-containing silazane compound represented by the above formula (7) is added to 100 g of an untreated silica filler having a specific surface area of 300 m ² / g (product name: AEROSIL 300: product name manufactured by Nippon Aerosil Co., Ltd.), and the temperature is 120 ° C. It was cooled and adjusted after stirring for a minute.
The value of M unit / (Q2 unit + Q3 unit) on the surface of the treated silica A was estimated by ²⁹ Si CP / MAS NMR and found to be 0.7.

  Furthermore, 0.2 parts by mass of a toluene solution (platinum concentration: 0.5% by weight) of a catalyst obtained by modifying chloroplatinic acid with a compound represented by the following formula (10) with respect to 120 parts by mass of the base, 50% of ethynylcyclohexanol 0.4 parts by mass of a toluene solution and 3.35 parts by mass of an organosilicon compound containing a SiH group represented by the following formula (11) were added and mixed uniformly to obtain a curable fluoropolyether rubber composition. .

An O-ring for measuring compression set was molded from the resulting composition under conditions of press cure at 150 ° C. for 10 minutes and further oven cure at 200 ° C. for 4 hours. Using this O-ring, the compression set after 120 ° C./500 hours (25% compression) was measured in air and in a 50% by weight aqueous solution of ethylene glycol according to JIS K6262. The results are shown in Table 1.

[Example 2]
In the same manner as in Example 1, except that treated silica B (specific surface area of 129 m ² / g) treated with equimolar treatment with a substituent containing a perfluoroalkyl group of C ₆ F ₁₃ — was used as a silica-based filler. And the composition was blended to obtain a curable fluoropolyether rubber composition.

Preparation method of treated silica B:
80 g of a fluorine-containing silazane compound represented by the above formula (8) is added to 100 g of an untreated silica filler having a specific surface area of 300 m ² / g (product name: AEROSIL 300: product name manufactured by Nippon Aerosil Co., Ltd.), and the temperature is 120 ° C. It was cooled and adjusted after stirring for a minute.
The value of M unit / (Q2 unit + Q3 unit) on the surface of the treated silica B was estimated by ²⁹ Si CP / MAS NMR and found to be 0.7.

Further, a measurement sample was prepared from the obtained composition in the same manner as in Example 1, and compression set characteristics were measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
Except for using treated silica C treated with hexamethyldisilazane (specific surface area 180 m ² / g, ²⁹ Si CP / MAS NMR, M units / (Q2 units + Q3 units) = 0.8) as a silica-based filler. Production of the base and blending of the composition were performed in the same manner as in Example 1 to obtain a curable fluoropolyether rubber composition.

Further, from the obtained composition, a measurement sample was prepared in the same manner as in the example, and the compression set characteristic was measured in the same manner as in the example. The results are shown in Table 1.

[Comparative Example 2]
Treated silica D treated with equimolar treatment with a substituent containing a CF ₃ -group as a silica-based filler (specific surface area 205 m ² / g, ²⁹ Si from CP / MAS NMR, M units / (Q2 units + Q3 units) = 0. Except for using 7), the base was produced and the composition was blended in the same manner as in Example 1 to obtain a curable fluoropolyether rubber composition.

  Further, from the obtained composition, a measurement sample was prepared in the same manner as in the example, and the compression set characteristic was measured in the same manner as in the example. The results are shown in Table 1.

[Example 3]
In Example 1, instead of the polymer represented by the chemical formula (9), a polymer represented by the following formula (12) (viscosity 3,700 mm ² / s, weight average molecular weight 15,000, vinyl group amount 0.0122) Mol / 100g)

実施例１において、化学式（１１）で示されるＳｉＨ基を含有する有機ケイ素化合物の代わりに下記式（１３）で表されるＳｉＨ化合物３．７８質量部

In Example 1, instead of the organosilicon compound containing the SiH group represented by the chemical formula (11), 3.78 parts by mass of the SiH compound represented by the following formula (13)

を配合する以外は、実施例１と同様の方法でベースの製造及び組成物の配合を行い、硬化性フルオロポリエーテル系ゴム組成物を得た。
更に得られた組成物から、実施例と同様に測定試料を作製し、実施例と同様の方法で圧縮永久歪特性の測定を行った。結果を表１に示す。

Except for blending, the production of the base and the blending of the composition were performed in the same manner as in Example 1 to obtain a curable fluoropolyether rubber composition.
Further, from the obtained composition, a measurement sample was prepared in the same manner as in the example, and the compression set characteristic was measured in the same manner as in the example. The results are shown in Table 1.

[Comparative Example 3]
In place of the treated silica A used in Example 3, treated silica C was used, and the base was produced and the composition was compounded in the same manner as in Example 3, and a curable fluoropolyether rubber composition was prepared. Got.
Further, from the obtained composition, a measurement sample was prepared in the same manner as in the example, and the compression set characteristic was measured in the same manner as in the example. The results are shown in Table 1.

表の解説：空気中の圧縮永久歪特性は、実施例、比較例共に大きな差異はないが、エチレングリコール５０％水溶液中においては、実施例の圧縮永久歪特性が比較例に比べて優れている。

Explanation of the table: The compression set characteristics in the air are not significantly different in the examples and comparative examples, but in the 50% aqueous solution of ethylene glycol, the compression set characteristics of the examples are superior to the comparative examples. .

Claims (2)

The component (a) has at least two alkenyl groups in the molecule, and -C _a F _2a O- in the main chain (wherein, a in each unit is an integer of 1 to 6 independently) 100 parts by mass of a linear perfluoropolyether compound having a divalent perfluoroalkyl ether structure containing a repeating unit of 5,000 to 100,000 and having a weight average molecular weight of 5,000 to 100,000 (b) BET specific surface area of 50 m ² / g or more 10 to 40 parts by mass of a silica-based filler having a surface hydrophobized with a fluorosilazane compound having a perfluoroalkyl group having 3 or more carbon atoms and a hydrolyzable group represented by the following general formula (5)
[(RfQ) _a Si (R ¹ ) _b (NR ² ) _{4-ab / 2} ] _l (5)
[Wherein R ^{1 s} may be the same or different and each represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group; R ² may be the same or different and represent a hydrogen atom or an alkyl group] Rf, which may be the same or different, is a perfluoroalkyl group having 3 to 20 carbon atoms; Q is a divalent organic group having 2 to 5 carbon atoms; In the structural unit, a is an integer of 1 to 3, b is an integer of 0 to 2, provided that a + b is an integer of 1 to 3, and l is an integer of 2 or more. ]
(C) The hydrosilylation reaction catalyst is 0.1 to 1,000 ppm in terms of platinum group metal based on the total amount of the composition.
(D) The fluorine-containing organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule is a ratio of SiH group in component (d) to alkenyl group in component (a) (SiH group / alkenyl group). ) Is contained in an amount of 0.4 to 5.0. A curable fluoropolyether rubber composition characterized by comprising: The curable fluoropolyether rubber composition according to claim 1 , wherein the component (a) is a polyfluorodialkenyl compound represented by the following general formula.
_{CH 2 = CH- (X) p} -Rf 1 - (X ') p -CH = CH 2 (3)
_{CH 2 = CH- (X) p} -Q-Rf 1 -Q- (X ') p -CH = CH 2 (4)
[-CH ₂ wherein, X is independently _{-, - CH 2 O -,} - CH 2 OCH 2 - or -Y-NR ¹ -CO- (where, Y is -CH ₂ - or the following structural formula (Z) And R ¹ is a hydrogen atom, a methyl group, a phenyl group or an allyl group.) And X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO. —NR ² —Y′— (where Y ′ is —CH ₂ — or a group represented by the following structural formula (Z ′), R ² is a hydrogen atom, a methyl group, a phenyl group, or an allyl group;

(O, m or p-dimethylsilylphenylene group)

A group represented by (o, m or p-dimethylsilylphenylene group). Rf ¹ is Ru perfluoropolyether structure der divalent. Q is a divalent hydrocarbon group having 1 to 15 carbon atoms, but it may also contain an ether bond. ), P is independently 0 or 1. ]