JP2005097369A - Curable fluoro polyether rubber composition and rubber product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable fluoro polyether rubber composition superior in heat resistance, chemical resistance, solvent resistance, water repellency, oil repellency and weather resistance, having strength suitable for practical use and providing a cured product of high hardness without mold wear, and to provide a rubber product containing the cured product. <P>SOLUTION: This curable fluoro polyether rubber composition comprises (A) a straight chain fluoro polyether compound having at least 2 alkenyl groups in a molecule and a perfluoro polyether structure in a back bone, (B) an organic silicon compound having at least 2 hydrogens bonded to a silicon atom in a molecule, (C) an alumina powder of an average particle diameter of 1 μm and (D) a catalyst for hydrosilylation. The rubber product containing the cured product is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is excellent in solvent resistance, chemical resistance, weather resistance, releasability, water repellency, oil repellency, heat resistance, has a practical mechanical strength, and obtains a cured product free from mold wear. The present invention relates to a curable fluoropolyether rubber composition capable of forming a rubber product and a rubber product containing the cured product.

  Conventionally, a linear fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain, and having at least two H-SiOSiO structures in one molecule From a composition comprising an organosilicon compound and a hydrosilylation reaction catalyst, to obtain a cured LIMS moldable material having excellent balance of properties such as heat resistance, chemical resistance, solvent resistance, water repellency, oil repellency, and weather resistance. Has been proposed (see Patent Document 1).

  However, such a fluoropolyether rubber composition is difficult to obtain a practical strength with a polymer alone, and the polymer itself is expensive. Therefore, a filler filler typified by fumed silica is used. Blended to improve physical properties and reduce composition costs. Addition of filler is an important compounding agent for adjusting the hardness of rubber.

  When the filler is highly filled, the purpose is to reduce the cost when it is desired to obtain a composition with high hardness. In this case, there is a limit to the amount of fumed silica to be added, and when it is added in a large amount, the viscosity increases and fluidity is lost, which makes molding difficult. Therefore, when a filler other than fumed silica is added for the purpose of suppressing an increase in viscosity, there is a problem that the strength is extremely lowered or mold wear occurs.

  That is, when fumed silica, which is a general filler, is used, the tensile strength of the cured product is good, but when it is highly filled, the viscosity increases and LIMS molding becomes impossible. There is a limit (see Patent Document 2). Therefore, fumed silica is excellent as a filler for low-hardness materials, but is not suitable for high-hardness materials that require high filling.

  In addition, pulverized silica, calcium carbonate, diatomaceous earth, carbon black, synthetic resin filler, and various metal oxide powders other than alumina, which are generally used as highly filled fillers, may decrease strength or die wear when filled. There is a thing that generates, and there is a limit of the addition amount.

Japanese Patent No. 2990646 JP 2000-248166 A

  The present invention has been made in view of the above circumstances, and is excellent in heat resistance, chemical resistance, solvent resistance, water repellency, oil repellency, weather resistance and the like, and has strength within a practical range and no mold wear. It is an object of the present invention to provide a curable fluoropolyether rubber composition that gives a cured product with high hardness and a rubber product containing the cured product.

  As a result of studying filler additives to achieve the above-mentioned object, the present inventor, when blended with an alumina powder having an average particle size of 1 μm or less, has no increase in viscosity, excellent mechanical strength, and generation of mold wear. It has been found that a curable fluoropolyether rubber composition having a high hardness can be obtained, and has led to the present invention.

Therefore, the present invention
(A) Linear fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain 100 parts by mass (B) Bonded to a silicon atom in one molecule Organosilicon compound having at least two hydrogen atoms (A) The amount of Si—H group of component (B) being 0.5 to 5 moles per mole of alkenyl group contained in component (C) Average particle diameter 1 μm or less of alumina powder 1 to 200 parts by mass (D) Hydrosilylation reaction catalyst A curable fluoropolyether rubber composition containing a catalytic amount and a rubber product containing the cured product are provided.

  The curable fluoropolyether rubber composition of the present invention has a high fluorine content, so it has excellent solvent resistance and chemical resistance, low moisture permeability and low surface energy. For automobiles, aircraft rubber materials, semiconductor manufacturing equipment seal materials, tent film materials, sealants, molded parts, extruded parts, coating materials, copier roll materials, which are excellent in acid resistance and oil resistance. It is useful for electrical moisture-proof coating materials, sensor potting materials, release paper materials, and the like. Further, there is no mold wear, and the hardness can be easily adjusted, and a particularly hard material can be provided with little increase in viscosity.

  Hereinafter, the present invention will be described in more detail. The component (A) of the present invention is a linear fluoropolyether compound having at least two alkenyl groups in one molecule and having a perfluoropolyether structure in the main chain.

The alkenyl group in this linear fluoropolyether compound is preferably an alkenyl group having 2 to 8 carbon atoms. For example, CH _{2 at} the end of a vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, etc. A group having a ═CH— structure, particularly a vinyl group or an allyl group is preferred. This alkenyl group may be directly bonded to both ends of the main chain of the linear fluoropolyether compound, or may be a divalent linking group such as —CH ₂ —, —CH ₂ O— or —Y—. NR—CO— [wherein Y is —CH ₂ — or

（ｏ，ｍ又はｐ位で示されるジメチルフェニルシリレン基）
であり、Ｒは水素原子、メチル基、フェニル基又はアリル基である。］等を介して結合していてもよい。アルケニル基は１分子中に少なくとも２個有する。

(Dimethylphenylsilylene group shown at o, m or p position)
And R is a hydrogen atom, a methyl group, a phenyl group or an allyl group. ] Or the like. There are at least two alkenyl groups in one molecule.

  The component (A) has a perfluoropolyether structure in the main chain. The perfluoropolyether structure will be described below.

(A) As a component, the polyfluoro dialkenyl compound which has the branch represented with following General formula (2) can be mentioned.
CH ₂ ═CH— (X) _a —Rf ¹ — (X ′) _a —CH═CH ₂ (2) [wherein X is —CH ₂ —, —CH ₂ O—, —CH ₂ OCH ₂ — or —Y—NR ¹ —CO— (Y is —CH ₂ — or the following structural formula (Z)

で示されるｏ，ｍ又はｐ−ジメチルシリルフェニレン基）で表される基、Ｒ^１は水素原子、置換若しくは非置換の一価炭化水素基、Ｘ’は−ＣＨ_２−、−ＯＣＨ_２−、−ＣＨ_２ＯＣＨ_２−又は−ＣＯ−ＮＲ^１−Ｙ’−（Ｙ’は−ＣＨ_２−又は下記構造式（Ｚ’）

O, m or a p-dimethylsilylphenylene group represented by formula (I), R ¹ is a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group, X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO—NR ¹ —Y′— (Y ′ is —CH ₂ — or the following structural formula (Z ′)

で示されるｏ，ｍ又はｐ−ジメチルシリルフェニレン基）で表される基であり、Ｒ^１は上記と同じ基である。Ｒｆ^１は二価のパーフルオロポリエーテル基であり、ａは独立に０又は１である。］

O, m or p-dimethylsilylphenylene group represented by formula (I), and R ¹ is the same group as described above. Rf ¹ is a divalent perfluoropolyether group, and a is independently 0 or 1. ]

Here, Rf ^{1 in the} general formula (2) is a divalent perfluoropolyether structure, and compounds represented by the following general formulas (i) and (ii) are preferable.

（式中、ｐ及びｑは１〜１５０の整数であって、かつｐとｑの和の平均は、２〜２００である。また、ｒは０〜６の整数、ｔは２又は３である。）

(In the formula, p and q are integers of 1 to 150, and the average of the sum of p and q is 2 to 200. Also, r is an integer of 0 to 6, and t is 2 or 3. .)

（式中、ｕは１〜２００の整数、ｖは１〜５０の整数、ｔは上記と同じである。）

(In the formula, u is an integer of 1 to 200, v is an integer of 1 to 50, and t is the same as above.)

  (A) As a preferable example of a component, the compound represented by following General formula (1) is mentioned.

［式中、Ｘは−ＣＨ_２−、−ＣＨ_２Ｏ−、−ＣＨ_２ＯＣＨ_２−又は−Ｙ−ＮＲ^１−ＣＯ−（Ｙは−ＣＨ_２−又は下記構造式（Ｚ）

[Wherein, X is _{-CH 2 -, - CH 2 O} -, - CH 2 OCH 2 - or ^-Y-NR 1 -CO- (Y is -CH ₂ - or the following structural formula (Z)

で示されるｏ，ｍ又はｐ−ジメチルシリルフェニレン基、Ｒ^１は水素原子、メチル基、フェニル基又はアリル基、Ｘ’は−ＣＨ_２−、−ＯＣＨ_２−、−ＣＨ_２ＯＣＨ_２−又は−ＣＯ−ＮＲ^１−Ｙ’−（Ｙ’は−ＣＨ_２−又は下記構造式（Ｚ’）

O, m, or p-dimethylsilylphenylene group, R ¹ is a hydrogen atom, methyl group, phenyl group or allyl group, X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —. CO—NR ¹ —Y′— (Y ′ is —CH ₂ — or the following structural formula (Z ′)

で示されるｏ，ｍ又はｐ−ジメチルシリルフェニレン基、Ｒ^１は上記と同じである。ａは独立に０又は１、Ｌは２〜６の整数、ｂ及びｃはそれぞれ０〜２００の整数である。］

O, m or p-dimethylsilylphenylene group represented by the above, R ¹ is the same as above. a is independently 0 or 1, L is an integer of 2 to 6, and b and c are integers of 0 to 200, respectively. ]

  Specific examples of the linear fluoropolyether 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０〜２００，ｍ＋ｎ＝６〜２００を満足する整数を示す。）

(In the formula, m and n are integers satisfying 0 to 200 and m + n = 6 to 200, respectively.)

  These linear fluoropolyether compounds can be used singly or in combination of two or more.

  The component (B) of the present invention is an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule. The component (B) functions as a crosslinking agent or chain extender for the component (A). From the viewpoint of compatibility with the component (A), dispersibility, and uniformity after curing, Those having one or more fluorine-containing groups are preferred.

Examples of the fluorine-containing group include those 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）_ｒ−（ＣＦ_２ＣＦ_２Ｏ）_ｓ−ＣＦ_２−
（但し、ｒ及びｓ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) r -} (CF 2 CF 2 O) s -CF 2 -
(However, r and s are each an integer of 1 to 50.)

In addition, as the divalent linking group that connects the perfluoroalkyl group, perfluorooxyalkyl group, perfluoroalkylene group or perfluorooxyalkylene group and the silicon atom, an alkylene group, an arylene group, and a combination thereof, or these In this group, an ether bond oxygen atom, an amide bond, a carbonyl bond, etc. may be interposed.
—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 such as

  Examples of the component (B) having such a fluorine-containing group include the following compounds. 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.

  The blending amount of the component (B) is such that the hydrosilyl group of the component (B), that is, the Si-H group is usually added to 1 mol of an alkenyl group such as a vinyl group, allyl group, cycloalkenyl group, etc. The amount is preferably 0.5 to 5 mol, more preferably 1 to 2 mol. If the amount is less than 0.5 mol, the degree of crosslinking may be insufficient. If the amount exceeds 5 mol, the extension of the chain length is prioritized, resulting in insufficient curing, foaming, heat resistance, compression. Permanent distortion characteristics may deteriorate.

  The component (C) of the present invention must be an alumina having an average particle diameter of 1 μm or less and not containing alumina having a particle diameter of 5 μm or more. In the present invention, the component (C) is particularly important and acts as a reinforcing filler with little reduction in mechanical properties, particularly tensile strength, and little increase in viscosity even when highly filled.

The alumina powder of component (C) is known in many crystal types such as α-type, β-type, γ-type, and θ-type depending on the crystal state. However, although the alumina used in the present invention does not depend on the crystal type, α-type alumina which is easily available industrially and has cost merit is preferable.
Further, the surface of the alumina powder may be treated with a silane or titanium surface treatment agent for the purpose of facilitating kneading workability or adjusting the composition viscosity, rubber strength and hardness.

  The average particle diameter of alumina is important and may be 1 μm or less, more preferably 0.005 to 0.5 μm, and still more preferably 0.01 to 0.3 μm. If the average particle size is 1 μm or more, the specific surface area will be small and the interaction between the polymer and alumina will be reduced, making it difficult to increase the strength, and alumina with a large particle size will pass through the mold gate at high speed during LIMS molding. The mold will be worn when doing so. In addition, it is difficult to industrially produce a filler of 0.005 μm or less, and in addition to the time required for compounding and kneading, it is difficult to completely disperse in the composition because the filler tends to agglomerate secondary. .

  Further, not only the average particle diameter but also the alumina content of the alumina powder having a particle diameter of 5 μm or more is preferably 0.01% by mass or less, more preferably the alumina content of 1.0 μm or more is 0%. 0.01% by mass or less. As described above, LIMS molding generally causes mold wear when alumina containing 0.01% by mass or more of particles of 5 μm or more is used to pass the material at a high speed through a narrow mold gate having a thickness of about 10 to 500 μm. This is not preferable.

  (C) As for the addition amount of a component, 1-200 mass parts is preferable with respect to 100 mass parts of (A) component. In particular, 20 to 100 parts by mass is preferable from the viewpoint of the balance between viscosity and mechanical properties and stability. If the amount is less than 1 part by mass, the effect of adding alumina may not be expected. If the amount exceeds 150 parts by mass, the viscosity may increase and the mechanical properties may be unfavorable.

  The component (D) of the present invention is a hydrosilylation reaction catalyst. The hydrosilylation reaction catalyst is a catalyst that promotes the addition reaction between the alkenyl group in component (A) and the hydrosilyl group in component (B). Since this hydrosilylation reaction catalyst is generally a noble metal compound and is expensive, platinum or platinum compounds that are relatively easily available are often used.

  The component (D) of the present invention is a hydrosilylation reaction catalyst. The hydrosilylation reaction catalyst is a catalyst that promotes the addition reaction between the alkenyl group in component (A) and the hydrosilyl group in component (B). Since this hydrosilylation reaction catalyst is generally a noble metal compound and is expensive, platinum or platinum compounds that are relatively easily available are often used.

Examples of the platinum compound include chloroplatinic acid or a complex of chloroplatinic acid and an olefin such as ethylene, a complex of alcohol or vinyl siloxane, metal platinum carrying silica, alumina, carbon or the like. Rhodium, ruthenium, iridium and palladium compounds are also known as platinum group metal catalysts other than platinum compounds. For example, RhCl (PPh ₃ ) ₃ , RhCl (CO) (PPh ₃ ) ₂ , Ru ₃ (CO) ₁₂ , IrCl (CO) (PPh ₃ ) ₂ , Pd (PPh ₃ ) _{4 and the} like can be exemplified.

  The compounding amount of the hydrosilylation reaction catalyst can be a catalytic amount, but is usually 0.1 to 100 ppm (in terms of platinum) with respect to 100 parts by mass of the total amount of the components (A), (B) and (C). It is preferable to mix | blend in a ratio.

  In the composition of the present invention, in addition to the components (A) to (D), various fillers such as reinforcing fillers may be added as the component (E) for the purpose of improving mechanical strength.

  Reinforcing fillers improve mechanical strength, thermal stability, weather resistance, chemical resistance or flame resistance, reduce thermal shrinkage during curing, and lower the thermal expansion coefficient of elastic bodies obtained by curing. Or added for the purpose of reducing gas permeability, but the main purpose is to improve mechanical strength.

  Examples of the filler used in combination as the component (E) include fumed silica, wet silica, pulverized silica, calcium carbonate, diatomaceous earth, carbon black, various metal oxide powders other than alumina, and the like. What processed with the processing agent may be used. Among these, fumed silica is particularly preferable from the viewpoint of improving mechanical strength, and further, fumed silica treated with a silane-based surface treatment agent is preferable from the viewpoint of improving dispersibility.

  Such silica-based fillers are those obtained by hydrophobizing dry process silica called fumed silica and wet process silica called precipitated silica. The hydrophobizing agent is preferably a hydrolyzable silicon compound such as dimethyldichlorosilane and organochlorosilane such as trimethylchlorosilane, a silazane compound such as hexamethyldisilazane, and a cyclic silazane such as hexamethylcyclotrisilazane. Of these, dry silica treated with organochlorosilane is preferable from the viewpoint of improving mechanical strength.

Further, the specific surface area of the hydrophobized silica needs to be 50 (m ² / g) or more in order to improve mechanical properties. Furthermore, since the thickening at the time of silica compounding in the composition becomes large and the compounding becomes difficult, it is necessary to be 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 a generally well-known technique should be adopted as a normal treatment method. For example, the untreated silica fine powder and the treatment agent are put in a mechanical kneading apparatus sealed at normal pressure or in a fluidized bed, and mixed at room temperature or heat treatment in the presence of an inert gas as necessary. Treated, and optionally catalyst and water for accelerating hydrolysis may be used and can be adjusted 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, it is preferable that the bulk density of a silica type filler is 30-80 g / l. If the bulk density of the silica-based filler is 30 g / l or less, the viscosity of the composition increases, making blending difficult, and this is not preferred, and if it is 80 g / l or more, a sufficient anti-adhesion effect is not imparted.

  As addition amount of a silica type filler, 5-200 mass parts is preferable with respect to 100 mass parts of (A) component. In particular, 10 to 60 parts by mass is preferable from the viewpoint of stability of mechanical properties. If the amount is less than 5 parts by mass, the mechanical strength is not improved, and if it exceeds 200 parts by mass, the increase in viscosity is large and blending is difficult.

  Furthermore, the curable fluoropolyether rubber composition of the present invention can be blended with appropriate pigments, dyes, and the like, if necessary. Moreover, various compounding agents can be added as long as the object of the present invention is not impaired. Examples of such an optional component include 1-ethynyl-1-hydroxycyclohexane, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 3-methyl-1- Acetylene alcohol such as penten-3-ol and phenylbutenol, 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne, and the like, or polymethylvinylsiloxane cyclic compound And a hydrosilylation reaction catalyst control agent such as an organic phosphorus compound, whereby the curing reactivity and storage stability can be kept moderate.

  The manufacturing method in particular of the curable composition of this invention is not restrict | limited, It can manufacture by kneading the said component. Two compositions may be mixed at the time of use.

  The cured product is formed by injecting the composition of the present invention into a suitable mold and curing the composition, or by coating the composition on a suitable substrate and curing the composition. By the method. Moreover, hardening can be easily performed by the process for about 10 seconds-30 minutes normally at the temperature of 100-180 degreeC.

  The fluoropolyether rubber composition of the present invention is excellent in heat resistance, chemical resistance, solvent resistance, water repellency, oil repellency, weather resistance, and the like by curing these, and has good compression set characteristics. Thus, a cured product excellent in mold release property, particularly mold release property can be formed, and can be used for various applications.

  In this case, rubber products using the cured product of the composition of the present invention are for automobiles, chemical plants, inkjet printers, semiconductor production lines, analytical / physical equipment, medical equipment, aircraft, and fuel cells. Etc., and can be used as rubber parts such as diaphragms, valves, O-rings, oil seals, gaskets, packings, joints, and face seals.

  More specifically, rubber products containing a cured product of the composition of the present invention are rubber parts for automobiles, rubber parts for chemical plants, rubber parts for ink jet printers, rubber parts for semiconductor production lines, rubber for analytical / chemical instruments. Parts, rubber parts for medical equipment, rubber parts for aircraft, etc., tent film materials, sealants, molded parts, extruded parts, coating materials, copier roll materials, moisture-proof coating materials for electric sensors, potting agents for sensors, seals for fuel cells Material, laminated rubber cloth, and the like.

  Rubber parts for automobiles include diaphragms for fuel and regulators, diaphragms for pulsation dampers, diaphragms for oil pressure switches, diaphragms for EGR, valves for canisters, valves for power control, etc. Examples thereof include O-rings such as O-rings and O-rings for ink jetters, and sealing materials such as oil seals and cylinder head gaskets.

  Examples of rubber parts for chemical plants include pump diaphragms, valves, O-rings, packings, oil seals, gaskets, and the like.

  Examples of rubber parts for inkjet printers and semiconductor parts for semiconductor production lines include diaphragms, valves, O-rings, packings, and gaskets.

  Examples of rubber parts for analytical / physical and chemical equipment and rubber parts for medical equipment include diaphragms for pumps, O-rings, packings, valves, and Jonto.

  Examples of aircraft rubber parts include O-rings for fluid piping such as aircraft engine oil, jet fuel, hydraulic oil, and skid roll, face seals, packings, gaskets, diaphragms, valves, and the like. Examples of the fuel cell rubber parts include a seal material between electrodes, an O-ring of hydrogen, air and cooling water piping, a face seal, packing, a gasket, a diaphragm, a valve and the like.

  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 the following examples, “part” means “part by mass” and “%” means “% by mass”.

The preparation of the base composition and the method for evaluating the rubber physical properties of the composition are shown below.
Production of base composition 100 parts of a polymer represented by the following formula (4) (viscosity 8500 cs, average molecular weight 22000, vinyl group amount 0.009 mol / 100 g) treated with a dimethylchlorosilane group having a specific surface area of 200 m ² / g 25 parts of fumed silica are added, mixed, heat treated, mixed on a three-roll mill, and 2.74 parts of a fluorine-containing organosilicon compound represented by the following formula (5) and chloroplatinic acid are represented by the following formula ( 6) Add 0.2 parts of a toluene solution (platinum concentration: 1.0% by weight) of the catalyst modified with the compound represented by 6) and 0.4 parts of fluorine-modified acetylene alcohol to prepare a base composition. did.

Rubber physical property evaluation method The composition was degassed under reduced pressure, placed in a rectangular frame with a thickness of 2 mm, vented again, and press-cured at 100 kg / cm ² and 150 ° C. for 10 minutes. The test piece was cut out from the cured sample, and physical properties such as hardness, elongation, tensile strength, and tear strength were measured according to JIS K6251, 6252, and 6253, and the viscosity was measured according to JIS K7117.

Mold wear resistance evaluation method ○ Molding machine used 7-ton LIMS molding machine (HM-7, LIMS specification, Nissei Plastics product name)
○ Mold used PRC, Gate pressure 50μm Material passing structure mold The mold wear condition after flowing 1kg of material to the above mold gate part was observed with a microscope ×: The mold part was worn, and the gate part was deformed.
Δ: Some evidence of mold wear is seen.
○: No mold wear, no change in gate before and after the test.

    [Examples 1 to 5, Comparative Example 1]

  Alumina powder I (AL-160SG-3: manufactured by Showa Denko) having the following average particle size and particle size distribution is added to the base composition in the amounts shown in Table 1, and after mixing, viscosity, mold wear and hardening Later rubber properties were evaluated. The results are shown in Table 1.

  Compared to Comparative Example 1 in which no additive was added, it was found that the physical properties such as viscosity and tensile strength were not significantly different in the Examples, although a large difference was observed in hardness.

[Comparative Examples 2 to 4]
Fillers C, D and E shown below were added to the base composition in the amounts shown in Table 2, and after mixing, the rubber physical properties after curing, release properties, release force, and compression set were evaluated in the same manner as in the examples. . The results are shown in Table 2. None of the fillers were satisfactory in terms of viscosity, strength, and mold wear.

  (Additives A to B) were added to the base composition in the amounts shown in Table 1, and after mixing, the rubber physical properties after release, release properties, release force, and compression set were evaluated. Table 1 shows the results of studying the additive species, and Table 2 shows the results of studying the addition amount. Here, the volatile remaining amount is a ratio of the amount that did not volatilize when weighed 1 g in a glass petri dish and heated at 200 ° C. for 4 hours.

[Comparative Example 5]
Alumina powder II (AL-170: manufactured by Showa Denko) having a larger particle size than the examples shown below is added to the base composition in the amounts shown in Table 2, and after mixing, viscosity, mold wear resistance As a result of the evaluation of the physical properties of the rubber after curing, the change in strength was large and mold wear was also confirmed.

[Comparative Example 6]
When 20 parts of filler F (smearous silica with a specific surface area of 200 m ² / g treated with dimethylsiloxy group, the same as that added to the base composition) is added to the base composition, the viscosity of the composition increases. As a result, it was difficult to measure the viscosity (more than 64000 Pa · s), and it was impossible to add and mix the crosslinking agent and catalyst necessary for the cured composition. It was difficult to obtain a curable composition having a high hardness due to drastic increase in viscosity only by silica filling.

Claims (8)

(A) Linear fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain 100 parts by mass (B) Bonded to a silicon atom in one molecule Organosilicon compound having at least two hydrogen atoms (A) The amount of Si—H group of component (B) being 0.5 to 5 moles per mole of alkenyl group contained in component (C) Average particle diameter 1 μm or less of alumina powder 1 to 200 parts by mass (D) Hydrosilylation reaction catalyst A curable fluoropolyether rubber composition containing a catalytic amount. 2. The curable fluoropolyether rubber according to claim 1, wherein the alumina (C) component has an average particle size of 0.005 to 0.5 [mu] m and an alumina content of 5 [mu] m or more is 0.01% by mass or less. Composition. The curable fluoropolyether rubber composition according to claim 1 or 2, wherein 5 to 200 parts by mass of a reinforcing filler is added as component (E) to 100 parts by mass of component (A). The curable fluoropolyether rubber composition according to any one of claims 1 to 3, wherein the component (E) is fumed silica treated with a silane surface treating agent. The component (A) is represented by the following general formula (1)

[Wherein, X is _{-CH 2 -, - CH 2 O} -, - CH 2 OCH 2 - or ^-Y-NR 1 -CO- (Y is -CH ₂ - or the following structural formula (Z)

(Dimethylphenylsilylene group shown at o, m or p position)
R ¹ is a hydrogen atom, methyl group, phenyl group or allyl group, X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO—NR ¹ —Y′—. (Y ′ is —CH ₂ — or the following structural formula (Z ′)

(Dimethylphenylsilylene group shown at o, m or p position)
R ¹ is the same group as described above. a is independently 0 or 1, L is an integer of 2 to 6, and b and c are integers of 0 to 200, respectively. ]
The curable fluoropolyether rubber composition according to claim 1, which is a linear fluoropolyether compound represented by the formula: A rubber product comprising a cured product of the curable fluoropolyether rubber composition according to any one of claims 1 to 3. The rubber product according to claim 4, which is used for automobiles, chemical plants, inkjet printers, semiconductor production lines, analytical / physical equipment, medical equipment, aircraft or fuel cells. The rubber product according to claim 4 or 5, which is a diaphragm, valve, O-ring, oil seal, gasket, packing, joint or face seal.