Thermosetting perfluoropolyether rubber composition

Abstract

A thermosetting perfluoropolyether rubber composition comprising, in a specific proportion: (A) a perfluoropolyether polymer having a specific structure with at least two alkenyl groups in its molecular chain; (B) a fluorinated organic hydrogenated polysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule; (C) a hydrosilicification reaction catalyst; and (D) a BET specific surface area of ​​50 m². The thermosetting perfluoropolyether rubber composition, containing 2 g or more of hydrophobic silica powder, can produce a cured product (perfluoropolyether rubber cured product) with excellent heat resistance, chemical resistance, solvent resistance, low-temperature properties and rubber physical properties (mechanical strength, elongation, etc.), and also has excellent injection molding properties and mold release properties.

Description

Thermosetting perfluoropolyether rubber composition The present invention relates to a thermosetting perfluoropolyether rubber composition that can produce a cured product (perfluoropolyether rubber cured product) that exhibits excellent heat resistance, chemical resistance, solvent resistance, low-temperature characteristics, and rubber properties (mechanical strength, elongation, etc.), and also exhibits excellent injection moldability and mold release properties. In recent years, the use of injection molding in the production of rubber molded products has increased in recent years to achieve labor-saving improvements through automation and other means. Consequently, there is a desire for rubber compositions that can be easily injection molded while exhibiting excellent cured properties such as heat resistance, chemical resistance, solvent resistance, low-temperature characteristics, and rubber properties (mechanical strength, elongation, etc.). Patent Document 1 (Japanese Patent Application Publication No. 2002-167502) discloses a curable composition with excellent heat resistance, chemical resistance, solvent resistance, and low-temperature properties. However, when attempting to achieve high-strength rubber properties with this composition, the composition results in a high viscosity, making it difficult to form a cured product using a liquid injection molding system (LIMS). Furthermore, to improve productivity, LIMS requires that the cured product be easily releasable from the mold after molding. However, the mold releasability of the cured product obtained from the composition disclosed in Patent Document 1 still needs to be improved. In the embodiment of Patent Document 2 (International Publication No. 2019 / 088132), a curable composition is described, which is composed of CH 2= ​​CHCH 2OCH 2CF 2(OC 2F 4) e -(OCF 2) f -CF 2CH 2OCH 2CH=CH 2 (wherein e = 40, f = 58), an organosilicon compound having two or more hydrogen atoms bonded to silicon atoms in one molecule, and a catalyst. However, the inventors have found through research that the rubber properties of the cured product of this composition are insufficient. [Prior Art] [Patent] [Patent Document 1] Japanese Patent Application Publication No. 2002-167502 [Patent Document 2] International Publication No. 2019 / 088132 [Patent Document 3] Japanese Patent Application Publication No. 2005-24695 [Problems to be solved by the invention] The present invention was made in light of the above circumstances, and its object is to provide a thermosetting perfluoropolyether rubber composition that can produce a cured product (perfluoropolyether rubber cured product) that exhibits excellent heat resistance, chemical resistance, solvent resistance, low-temperature characteristics, and rubber properties (mechanical strength, elongation, etc.), while also exhibiting excellent liquid injection moldability and mold release properties. [Means for Solving the Problems] The present inventors have conducted extensive research to achieve the above-mentioned object and have discovered a thermosetting perfluoropolyether rubber composition comprising, in specific proportions, (A) a perfluoropolyether polymer having at least two alkenyl groups in its molecular chain represented by the general formula (1) or (2) described below, (B) a fluorinated organic hydrogenated polysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, (C) a hydrosilation reaction catalyst, and (D) a BET specific surface area of ​​50 m 2 The present invention has been completed by discovering that a thermosetting perfluoropolyether rubber composition containing hydrophobic silica powder having a concentration of 100 μg or more has excellent injection moldability and mold releasability. Furthermore, the obtained cured product (cured perfluoropolyether rubber) also has excellent heat resistance, chemical resistance, solvent resistance, low-temperature characteristics, and rubber properties (mechanical strength, elongation, etc.). Therefore, the present invention provides the following thermosetting perfluoropolyether rubber composition. [1] A thermosetting perfluoropolyether rubber composition comprising the following components (A) to (D): (A) 100 parts by mass of a perfluoropolyether polymer having at least two alkenyl groups in its molecular chain represented by the following general formula (1) or (2); [wherein, Rf is a perfluoropolyoxyalkylene group represented by the following general formula (3), (wherein, p, q, r, s, t, and u are each independently an integer from 0 to 450, and p+q+r+s+t+u is an integer from 20 to 450. The arrangement of the fluorooxyalkylene units enclosed by the parentheses labeled p, q, r, s, t, and u may be block or random, and v in each unit is independently an integer from 1 to 3); L is independently a single bond, or an oxygen atom, a sulfur atom, or a divalent organic group; M is independently a single bond, or a group containing a nitrogen atom, a silicon atom, a carbon atom, a phosphorus atom, or such a group, or a divalent to octavalent organic group; W is independently an alkenyl group or a monovalent organic group having an alkenyl group at a terminal; a is independently an integer from 1 to 7; Q is independently a single bond or a divalent organic group; Y is independently a divalent organic group having an alkenyl group; b is independently an integer from 1 to 10; B is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom]; (B) Fluorinated organohydrogen polysiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule: 0.5 to 5 moles of hydrogen atoms bonded to silicon atoms (SiH groups) in component (B) per 1 mole of alkenyl groups in component (A); (C) Hydrosilation catalyst: catalyst amount; (D) BET specific surface area of ​​50 m 2 / g or more hydrophobic silica powder: 10 to 40 parts by mass. [2]. The thermosetting perfluoropolyether rubber composition of [1], wherein in the formulas (1) and (2) of the component (A), Rf is a perfluoropolyoxyalkylene group represented by the following general formula (3'), (wherein p, q, r, s and v are the same as those described above, and p+q+r+s is an integer from 20 to 450, and each fluoroalkylene unit enclosed by the brackets marked p, q, r, s may be a block or a random group.) [3]. Thermosetting perfluoropolyether rubber composition as in [1] or [2], wherein the hydrophobic silica powder of component (D) is subjected to surface hydrophobic treatment using at least one organosilicon compound selected from the group consisting of organochlorosilane, organoalkoxysilane, organodisilazane and cyclic organopolysilazane. [4]. Thermosetting perfluoropolyether rubber composition as in any one of [1] to [3], wherein the surface carbon content of the hydrophobic silica powder of component (D) is 0.1 to 20% by mass of the total hydrophobic silica powder. [5] The thermosetting perfluoropolyether rubber composition according to any one of [1] to [4], further comprising (E) a hydrosilation reaction inhibitor. [6] The thermosetting perfluoropolyether rubber composition according to any one of [1] to [5], which is for injection molding. [Effects of the Invention] The thermosetting perfluoropolyether rubber composition of the present invention can provide a thermosetting perfluoropolyether rubber composition that can produce a cured product (cured perfluoropolyether rubber) having excellent heat resistance, chemical resistance, solvent resistance, low-temperature characteristics, and rubber properties (mechanical strength, elongation, etc.), while also exhibiting excellent liquid injection moldability and mold releasability. [Best Mode for Carrying Out the Invention] Hereinafter, the present invention will be described in detail. [Component (A)] Component (A) is a perfluoropolyether polymer represented by the following general formula (1) or (2) having at least two alkenyl groups in its molecular chain, and functions as a main agent (matrix polymer) of the thermosetting perfluoropolyether rubber composition of the present invention. [wherein, Rf is a perfluoropolyoxyalkylene group represented by the following general formula (3), (wherein, p, q, r, s, t, and u are each independently an integer of 0 to 450, and p+q+r+s+t+u is an integer of 20 to 450. The arrangement of the fluorooxyalkylene units enclosed in the parentheses marked p, q, r, s, t, and u may be block or random, and v in each unit is independently an integer of 1 to 3); L is independently a single bond, or an oxygen atom, a sulfur atom, or a divalent organic group; M is independently a single bond, or a group containing a nitrogen atom, a silicon atom, a carbon atom, a phosphorus atom, or such a group, or a divalent to octavalent organic group; W is independently an alkenyl group or a monovalent organic group having an alkenyl group at a terminal; a is independently an integer of 1 to 7; Q is independently a single bond or a divalent organic group; Y is independently a divalent organic group having an alkenyl group; b is independently an integer of 1 to 10; and B is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom]. In formulae (1) and (2), Rf is a perfluoropolyoxyalkylene group represented by the following general formula (3). (wherein, p, q, r, s, t, and u are each independently an integer from 0 to 450, and p+q+r+s+t+u is an integer from 20 to 450. The arrangement of the fluoroalkylene units enclosed in the parentheses marked with p, q, r, s, t, and u may be block or random, and v is independently an integer from 1 to 3 in each unit.) In the above formula (3), p, q, r, s, t, and u are each independently an integer of 0 to 450, preferably p is an integer of 1 to 200, q is an integer of 1 to 200, r is an integer of 0 to 200, s is an integer of 0 to 200, t is an integer of 0 to 200, and u is an integer of 0 to 200, and p+q+r+s+t+u is an integer of 20 to 450, preferably an integer of 25 to 300. Furthermore, each of the fluorooxyalkylene units enclosed in parentheses labeled s, t, and u is preferably linear. That is, since the perfluoropolyoxyalkylene group of component (A) has low viscosity, it is preferred that all of the fluorooxyalkylene units be linear in order to obtain a composition having excellent injection moldability. Furthermore, the arrangement of the fluorooxyalkylene units enclosed by the parentheses labeled p, q, r, s, t, and u may be block or random. Furthermore, v in each unit is independently an integer of 1 to 3, preferably 1 or 2. The alkylene group may be linear or branched. As the perfluoropolyoxyalkylene group represented by the formula (3), a perfluoropolyoxyalkylene group represented by the following general formula (3') is further preferred. In the above formula (3'), p, q, r, s, and v are the same as those in the above formula (3). Preferably, p is an integer of 1 to 200, q is an integer of 1 to 200, r is an integer of 0 to 200, and s is an integer of 0 to 200, and p+q+r+s is an integer of 20 to 450, preferably an integer of 25 to 300. v is preferably 1 or 2 (i.e., t=u=0 in formula (3)). Furthermore, the fluoroalkylene units enclosed by the parentheses labeled p, q, r, and s may be block or random. Furthermore, the fluoroalkylene units enclosed by the parentheses labeled s are preferably linear. Examples of Rf include those shown below. (In the formula, p1 is an integer of 1 to 200, q1 is an integer of 1 to 200, r1 is an integer of 1 to 200, and s1 is an integer of 1 to 200, and the total of p1, q1, r1, and s1 in each formula is an integer in the range of 20 to 450. In addition, each fluorooxyalkylene unit enclosed in parentheses may be block or random) In the above formula (1), L is a single bond, an oxygen atom, a sulfur atom, or a divalent organic group, and is a linking group between the Rf group and the M group (or the W group). The divalent organic group is preferably a diorganosilyl group selected from an amide bond, an ether bond, a carbonyl bond, an ester bond, or a dimethylsilyl group, -Si[OH][(CH 2) c1 Si(Me) 3]-(c1 is an integer of 2 to 4, Me is methyl) and is one or more unsubstituted or substituted divalent organic groups having 1 to 12 carbon atoms, preferably an unsubstituted or substituted divalent hydrocarbon group having 1 to 12 carbon atoms which may contain the aforementioned structure. Examples of the unsubstituted or substituted divalent hydrocarbon group having 1 to 12 carbon atoms include alkylene groups such as methylene, ethylene, propylene (trimethylene, methylethylene), butylene (tetramethylene, methylpropylene), hexamethylene, and octamethylene; arylene groups such as phenylene; and combinations of two or more of these groups (alkylene-arylene, etc.). Furthermore, some or all of the hydrogen atoms bonded to the carbon atoms of these groups may be substituted with halogen atoms such as fluorine or iodine. Preferred among these groups are unsubstituted or substituted alkylene groups or phenylene groups having 1 to 4 carbon atoms. Examples of the divalent organic group represented by L include groups represented by the following structures. In the following structure, it is preferred that the left-side bonding portion is bonded to Rf, and the right-side bonding portion is bonded to M or W. (wherein, C1 is independently an integer of 2 to 4, C2 is independently an integer of 1 to 4, C3 is an integer of 2 to 6, preferably an integer of 2 to 4, Me is a methyl group, and Et is an ethyl group) In the above formula (1), M is a single bond, or a nitrogen atom, a silicon atom, a carbon atom, a phosphorus atom, or a group thereof, or an organic group having 2 to 8 valences (the above (a+1) valences), and is a linking group between the L group (or the Rf group) and the W group. Specifically, examples include a single bond, -R 1 a divalent group represented by 2C-, -R 3 A divalent group represented by 2Si-, -NR 4 - a divalent group represented by, -N = a trivalent group represented by, -CO-N = a trivalent group represented by, -P = a trivalent group represented by, -PO = a trivalent group represented by, -R 1 C = trivalent group represented by -R 3 a trivalent group represented by Si=, a trivalent isocyanuric group, a tetravalent group represented by -C≡, a tetravalent group represented by -OC≡, a tetravalent group represented by -Si≡, a di- to octavalent siloxane residue, and the like. In the above, R 1Preferably, each of them is independently an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, a group having a repeating unit of an oxyalkylene group having 1 to 3 carbon atoms which can be inserted into a diorganosiloxane structure having 2 to 51 silicon atoms, or R 2 3SiO- represented by a silyl ether group, and R 2 R is independently a hydrogen atom, preferably an alkyl group having 1 to 3 carbon atoms, an aryl group such as a phenyl group, or an alkoxy group having 1 to 3 carbon atoms. 3 Preferably, they are independently an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 or 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a chloro group. 4 is an alkyl group with 1 to 3 carbon atoms, an aryl group with 6 to 10 carbon atoms, such as a phenyl group. When M is a siloxane residue, it is preferably a linear, branched, or cyclic organopolysiloxane structure having 2 to 51 silicon atoms (preferably 2 to 13 silicon atoms, more preferably 2 to 11 silicon atoms, and more preferably 2 to 5 silicon atoms). The organopolysiloxane may have methyl, ethyl, propyl, butyl, and C 3F 7-C 3H 6- or other unsubstituted or fluorine-substituted alkyl groups, or may have a phenyl group. In addition, it may contain a silylene structure in which two silicon atoms are bonded to an alkylene group, that is, Si-(CH 2) c3 In the above formula, c3 is an integer of 2-6, preferably an integer of 2-4. Examples of such M include the following: In the following structure, the trivalent group represented by -CO-N= is preferably one in which the carbon atom is bonded to L or Rf, and the nitrogen atom is bonded to W. (wherein, C4 is an integer of 1 to 20, C5 is an integer of 1 to 50, and Me is a methyl group) In the above formula (1), W is an alkenyl group or a monovalent organic group having an alkenyl group at the terminal, and is preferably an alkenyl group or a group represented by the following formula. (Where R 5 is alkenyl, R 6 is an alkyl group having 1 to 4 carbon atoms or a phenyl group, C6 is an integer of 0 to 10, and d is an integer of 1 to 3) Here, the alkenyl group as W and R in the above formula 5 The alkenyl group of W is preferably vinyl, butenyl, pentenyl, hexenyl, etc., and the alkenyl group of carbon number 2 to 10 is preferably vinyl, butenyl, pentenyl, and hexenyl. 5 The alkenyl group is preferably vinyl or allyl. 6 is an alkyl group such as a methyl group or an ethyl group having 1 to 4 carbon atoms, or a phenyl group, preferably a methyl group. c6 is an integer of 0 to 10, preferably an integer of 0 to 3, and d is an integer of 1 to 3, preferably 1. Examples of such W include the following. In formula (1), a is an integer of 1 to 7, preferably an integer of 1 to 3. In formula (1), as -MW a Examples of the structures shown include the following structures. (Where R 5 、R 6 , c5, c6, d are as described above, c7 is an integer of 0 to 8, preferably an integer of 0 to 3, and Me is a methyl group) In the above formula (2), Q is a single bond or a divalent organic group, and is a linking group between the Rf group and the Y group. The divalent organic group of Q is preferably a diorganosilyl group selected from an amide bond, an ether bond, an ester bond, or a dimethylsilyl group, -Si[OH][(CH 2) c1 Si(Me) 3]-(c1 is an integer of 2 to 4, Me is methyl) and is one or more unsubstituted or substituted divalent organic groups having 1 to 12 carbon atoms, preferably an unsubstituted or substituted divalent hydrocarbon group having 1 to 12 carbon atoms which may contain the aforementioned structure. Examples of the unsubstituted or substituted divalent hydrocarbon group having 1 to 12 carbon atoms include the same ones as those exemplified for the unsubstituted or substituted divalent hydrocarbon group having 1 to 12 carbon atoms in L. Examples of the divalent organic group represented by Q include groups represented by the following structures: In the following structure, it is preferred that the left-side bonding portion is bonded to Rf, and the right-side bonding portion is bonded to Y. (wherein, C1, C2, and C3 are the same as above, and Me is a methyl group) In the above formula (2), Y is a divalent organic group having an alkenyl group, and preferably has a structure represented by the following formula. (Where R 5 、R 6 , c6, c7 and d are as described above. e is an integer of 1 to 6, preferably 1 or 2. M' is an unsubstituted or substituted 3-8-valent, preferably 3-valent or 4-valent hydrocarbon group. Some or all of the carbon atoms in the hydrocarbon group may be substituted with silicon atoms, and some or all of the hydrogen atoms bonded to the carbon atoms may be substituted with halogen atoms such as fluorine atoms. As M', a group represented by the following structure is preferred. (In the above, M 1 M is a single bond, an unsubstituted or substituted divalent hydrocarbon group having 1 to 6 carbon atoms, or a diorganosilyl group such as a dimethylsilyl group; 2 -R 1 C = trivalent group represented by or -R 3 Si = trivalent group represented by 1 、R 3 The system is the same as above; R 7 is a hydrogen atom or a monovalent hydrocarbon group such as an alkyl group such as a methyl group, an ethyl group, or a propyl group having 1 to 6 carbon atoms) As M 1 , examples include single bond, phenylene, dimethylsilylene, tetrafluoroethylene, etc. 2 , the following expressions can be cited. (wherein Me is a methyl group) Examples of such Y include the following groups: Preferably, the left side is the direction of bonding to Q or Rf, and the right side is the direction of bonding to B. (Where R 5 、R 6 , c6, c7 and d are the same as above, c6' is an integer of 2 to 10, preferably 2 or 3, and Me is a methyl group) In the above formula (2), b is independently an integer of 1 to 10, preferably an integer of 1 to 4. Further, B is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms such as methyl, ethyl, propyl, and butyl, or a halogen atom such as fluorine, chlorine, bromine, and iodine. Examples of the alkenyl group-containing perfluoropolyether polymer represented by the above formula (1) or (2) include the following structures: In the following formula, Me represents a methyl group. (In the formula, p1, q1, r1, s1, and the sum of p1, q1, r1, and s1 in each formula are the same as described above; qs1 is an integer from 0 to 222, qs2 is an integer from 0 to 222, and the sum of qs1 and qs2 is an integer from 8 to 222. In addition, each fluorooxyalkylene unit enclosed in parentheses may be block or random.) Component (A) has at least 2, preferably 2 to 6, alkenyl groups in the molecular chain, and the content of the alkenyl groups is preferably 0.005 to 0.3 mol / 100g, more preferably 0.007 to 0.2 mol / 100g. 1 The obtained value was measured by H-NMR. The perfluoropolyether polymer of the component (A) may be used alone or in combination of two or more. [Component (B)] Component (B) is a fluorinated organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, preferably a fluorinated organohydrogenpolysiloxane having a perfluoroalkyl group or a perfluorooxyalkyl group, or a perfluoroalkylene group or a perfluorooxyalkylene group and further having two or more hydrogen atoms (SiH groups) directly bonded to silicon atoms in one molecule, and having no alkoxy group directly bonded to an epoxy group or a silicon atom in the molecule (fluorinated organohydrogenpolysiloxane); component (B) functions as a crosslinking agent for component (A). The perfluoroalkyl group, perfluorooxyalkyl group, perfluoroalkylene group and perfluorooxyalkylene group are introduced from the viewpoints of compatibility with the component (A), dispersibility and uniformity after curing. Examples of the perfluoroalkyl group or perfluorooxyalkyl group include groups represented by the following general formula (4), (5) or (6). (In formula (4), f is an integer of 1 to 10, preferably an integer of 3 to 7) (In formula (5), k and l are each an integer from 1 to 50, preferably an integer from 1 to 30, and the average value of k+l is 2 to 100, preferably 2 to 60; each repeating unit may be randomly bonded to each other) (In formula (6), g is an integer of 1 to 50, preferably an integer of 2 to 30) Examples of the perfluoroalkylene group or perfluorooxyalkylene group include groups represented by the following general formulas (7) to (9). (In formula (7), h is an integer of 1 to 20, preferably an integer of 2 to 10) (In formula (8), i and j are each an integer greater than 1, preferably an integer from 1 to 100, and the average value of i+j is 2 to 200, preferably 2 to 100) (In formula (9), k and l are each an integer from 1 to 50, preferably an integer from 1 to 30, and the average value of k+l is 2 to 100, preferably 2 to 60. The repeating units may be randomly bonded to each other.) Furthermore, the perfluoroalkyl group, perfluorooxyalkyl group, perfluoroalkylene group, or perfluorooxyalkylene group is preferably connected to the silicon atom constituting the polysiloxane via a divalent linking group. As the divalent linking group, an unsubstituted or substituted divalent hydrocarbon group having 2 to 13 carbon atoms (particularly 2 to 8 carbon atoms) which may have an oxygen atom, a nitrogen atom, or a silicon atom is preferred. Specifically, examples include alkylene groups, arylene groups, and combinations thereof, or structures in which one or more of the groups selected from the group consisting of ether bond oxygen atoms, amide bonds, carbonyl bonds, ester bonds, and dimethylsilylene groups are inserted into the groups. For example, the following groups having 2 to 13 carbon atoms can be cited: (However, Me is a methyl group, Et is an ethyl group, iPr is an isopropyl group, Ph is a phenyl group, and Ph' is a phenylene group.) Furthermore, in the above-described structure, it is preferred that the left-side bonding portion is bonded to a silicon atom constituting the polysiloxane, and the right-side bonding portion is bonded to a perfluoroalkyl group, a perfluorooxyalkyl group, a perfluoroalkylene group, or a perfluorooxyalkylene group. In the fluorinated organohydrogenpolysiloxane of component (B), the monovalent or divalent fluorinated organic group and the monovalent substituent bonded to a silicon atom other than a hydrogen atom directly bonded to a silicon atom (i.e., a SiH group) are unsubstituted or substituted alkyl groups having 1 to 20 carbon atoms (preferably 1 to 12 carbon atoms) or aryl groups having 6 to 20 carbon atoms (preferably 6 to 12 carbon atoms), for example, alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, cyclohexyl, octyl, and decyl; aryl groups such as phenyl, tolyl, and naphthyl; and groups in which some or all of the hydrogen atoms in such groups are substituted with a halogen atom such as chlorine, or a cyano group, for example, chloromethyl, chloropropyl, and cyanoethyl. Among these, a methyl group is preferred. Furthermore, the polysiloxane does not contain an epoxy group or an alkoxy group. The structure of the fluorinated organic hydrogen polysiloxane as component (B) may be cyclic, chain, three-dimensional network or a combination thereof. The number of silicon atoms in the fluorinated organic hydrogen polysiloxane is not particularly limited, but is generally 2 to 60, preferably 3 to 30, and more preferably about 4 to 30. Furthermore, component (B) has two or more SiH groups in one molecule, preferably three or more, and the content of the SiH groups is preferably 0.0001 to 0.02 mol / g, more preferably 0.0002 to 0.01 mol / g. In the present invention, the content of SiH groups is determined by 1 The obtained value was measured by H-NMR. Examples of the component (B) include those represented by the following general formulas (10) to (16). (In formula (10), A is independently a perfluoroalkyl group or a perfluorooxyalkyl group bonded to the silicon atom constituting the siloxane via a divalent hydrocarbon group which may have an oxygen atom, a nitrogen atom or a silicon atom. Examples of the perfluoroalkyl group or perfluorooxyalkyl group include those represented by the general formulas (4) to (6). R 8 are independently an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms (preferably 1 to 12 carbon atoms) or an aryl group having 6 to 20 carbon atoms (preferably 6 to 12 carbon atoms). α is an integer of 2 to 6, preferably an integer of 3 to 6, β is an integer of 1 to 4, preferably an integer of 1 to 3, and α+β is an integer of 4 to 10, preferably an integer of 4 to 9. However, -(Si(H)(R 8 )O)-with-(Si(A)(R 8 The bonding order of )O)- is not limited) (In formula (11), A is independent of each other and is the same as the above A, R 8 Independent of each other and with the above R 8 are the same, and γ is an integer of 2 to 50, preferably an integer of 3 to 30) (In formula (12), A is independent of each other and is the same as the above A, R 8 are independent of each other and are 8 are the same, γ is an integer of 2 to 50, preferably an integer of 3 to 30, δ is an integer of 1 to 40, preferably an integer of 1 to 20, and γ+δ is an integer of 4 to 60, preferably an integer of 4 to 50. However, -(Si(H)(R 8 )O)-with-(Si(A)(R 8 The bonding order of )O)- is not limited) (In formula (13), A is independent of each other and is the same as the above A, R 8 Independent of each other and with the above R 8 are the same, γ is an integer of 2 to 50, preferably an integer of 3 to 30, ε is an integer of 1 to 40, preferably an integer of 1 to 20, and γ+ε is an integer of 4 to 60, preferably an integer of 4 to 50. However, -(Si(H)(R 8 )O)-and-(Si(R 8 ) 2O)- bonding order is not limited) (In formula (14), A is independent of each other and is the same as the above A, R 8 Independent of each other and with the above R 8 are the same, γ is an integer of 2 to 50, preferably an integer of 3 to 30, δ is an integer of 1 to 40, preferably an integer of 1 to 20, ε is an integer of 1 to 40, preferably an integer of 1 to 20, and γ+δ+ε is an integer of 5 to 60, preferably an integer of 5 to 50. However, -(Si(H)(R 8 )O)-、-(Si(A)(R 8 )O)- and -(Si(R 8 ) 2O)- bonding order is not limited) (In formula (15), D is an oxygen atom, an alkylene group, or a perfluoroalkylene group or a perfluorooxyalkylene group bonded to an adjacent silicon atom via a divalent hydrocarbon group which may have an oxygen atom or a nitrogen atom. As the perfluoroalkylene group or the perfluorooxyalkylene group, any of the groups represented by the general formulae (7) to (9) above can be cited. In addition, A is independent of each other and is the same as A above, and R 8 Independent of each other and with the above R 8 are the same. Moreover, ζ is an integer of 0 to 3, η is an integer of 0 to 3, and ζ+η is an integer of 2 to 6, preferably an integer of 3 to 5. However, in formula (15), there is at least one group selected from perfluoroalkyl, perfluorooxyalkyl, perfluoroalkylene and perfluorooxyalkylene) (In formula (16), A is the same as A above, R 8 Independent of each other and with the above R 8 are the same) Component (B) specifically includes the following compounds. These compounds may be used alone or in combination of two or more. In the following formula, Me represents a methyl group and Ph represents a phenyl group. The arrangement of the siloxane units is random. (In the formula, f' is an integer of 1 to 10, g' is an integer of 1 to 50, and h' is an integer of 1 to 20. i' and j' are each an integer of 1 to 100, and i'+j' is an integer of 2 to 200. k' and l' are each an integer of 1 to 50, and k'+l' is an integer of 2 to 100. In addition, each repeating unit enclosed in the parentheses marked with k' and l' may be randomly bonded.) The amount of component (B) blended is such that the molar ratio of hydrogen atoms bonded to silicon atoms (SiH groups) in component (B) is 0.5 to 5 moles, preferably 0.6 to 3 moles, per 1 mole of alkenyl groups in component (A). If the amount of SiH groups is less than 0.5 moles, the degree of crosslinking will be insufficient. On the other hand, if the amount is greater than 5 moles, storage stability will be impaired, and the heat resistance of the resulting cured product will be reduced. Moreover, when the polyfluoro monoalkenyl compound (plasticizer, viscosity modifier and / or flexibility imparting agent) or the adhesion enhancer described later is formulated as an optional component, the amount of hydrogen atoms bonded to silicon atoms (SiH groups) contained in the composition (particularly the total amount of hydrogen atoms bonded to silicon atoms (SiH groups) contained in the above-mentioned component (B) and the adhesion enhancer) is preferably 0.5 to 5 mols relative to 1 mol of the alkenyl groups contained in the composition of the present invention (particularly the total amount of the alkenyl groups in the above-mentioned component (A) and the polyfluoro monoalkenyl compound (plasticizer, viscosity modifier and / or flexibility imparting agent) described later). The fluorinated organohydrogenpolysiloxane as the component (B) may be used alone or in combination of two or more. [Component (C)] The hydrosilation catalyst, component (C), promotes the addition reaction between components (A) and (B). Hydrosilation catalysts are typically noble metals (particularly platinum group metals) or their compounds. Due to their high cost, platinum or platinum compounds are often used, as they are more readily available. Examples of platinum compounds include chloroplatinic acid or complexes of chloroplatinic acid with olefins such as ethylene, complexes of chloroplatinic acid with alcohols or vinylsiloxanes, and metallic platinum supported on silica, alumina, carbon, and the like. Other hydrosilation catalysts known as catalysts other than platinum or platinum compounds include rhodium, ruthenium, iridium, and palladium compounds, such as RhCl(PPh 3) 3. RhCl(CO)(PPh 3) 2. Ru 3(CO) 12 、IrCl(CO)(PPh 3) 2. Pd(PPh 3) 4, etc. Still, in the above formula, Ph is phenyl. When using such catalysts, if they are solid catalysts, they can also be used in solid form. However, in order to obtain a more uniform cured product, it is preferably used in the form of a solution, dissolving chloroplatinic acid or the complex in a suitable solvent such as toluene or ethanol. The component (C) may be used alone or in combination of two or more. The amount of catalyst used is not particularly limited and can be adjusted to achieve the desired curing speed. However, for economical efficiency and a good cured product, the amount is generally 0.1 to 2,000 ppm, preferably 0.1 to 500 ppm, and particularly preferably 0.5 to 200 ppm (calculated as the mass of platinum group metal atoms) relative to the mass of the component (A). This amount can be appropriately increased or decreased depending on the desired curing speed. The conditions for the addition reaction (hydrosilation reaction) can be appropriately selected. The reaction can be carried out at room temperature (25°C ± 10°C, the same applies hereinafter). However, in order to accelerate the reaction, it can also be carried out by heating to 50-200°C. [Component (D)] The hydrophobic silica powder of component (D) functions as a reinforcing filler and improves the rubber properties such as mechanical strength (rubber hardness, tensile strength, tear strength, and elongation at break) of the cured rubber-like elastomer (elastomer) (cured perfluoropolyether rubber) obtained by curing the thermosetting perfluoropolyether rubber composition of the present invention. Furthermore, when the thermosetting perfluoropolyether rubber composition of the present invention is cured by injection molding, it exhibits excellent injection moldability and mold releasability. The hydrophobic silica powder as the component (D) is prepared by using an organic chlorosilane selected from dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, vinyldimethylchlorosilane, divinylmethylchlorosilane, trivinylchlorosilane, or dimethyldimethoxysilane, trimethylmethoxysilane, methyltrimethoxysilane, vinyldimethylmethoxysilane, divinylmethylmethoxysilane, trivinylmethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, methyl Silane compounds having a hydrolyzable group such as organoalkoxysilanes such as triethoxysilane, vinyldimethylethoxysilane, divinylmethylethoxysilane, and trivinylethoxysilane; organic disilazane compounds such as hexamethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 1,3-diphenyl-1,1,3,3-tetramethyldisilazane, heptamethyldisilazane, and 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisilazane; At least one organosilicon compound such as silazane, 1,3,5-trimethyl-1,3,5-trivinylcyclotrisilazane, 1,1,3,3,5,5-hexamethylcyclotrisilazane, etc., is used to hydrophobize the surface of silica powders such as fumed silica (fumed silica or dry silica), precipitated silica (wet silica), spherical silica (fused silica), sol-gel silica, and silica aerogel. In addition to hydrophobic silica powder obtained by further treating the surface of the surface-hydrophobized silica powder with a fluorinated organosilane or fluorinated organosiloxane having a perfluoroalkyl group or a perfluorooxyalkyl group, examples of hydrophobic silica powders include quartz powder (crystalline silica), fused silica powder, and diatomaceous earth that have been subjected to the same surface-hydrophobicization treatment as described above. Among these, fumed silica is particularly preferred in terms of improving mechanical strength, liquid injection molding properties (LIMS moldability), mold release properties, and dispersion stability of each component. In the hydrophobic treatment, the silica powder treated with a surface treatment agent on the surface of the silica is directly treated in the state of powder in advance. As a common treatment method, generally known technology can be used. For example, the untreated silica powder and one or more treatment agents are placed in a normal pressure and closed mechanical mixing device or a fluidized bed. In response to the need, in the presence of an inert gas, mixed treatment is carried out at room temperature or heat treatment. Water can be used to promote catalyst and hydrolysis as appropriate, and can be modulated by drying after mixing. The amount of the surface treatment agent is as long as it is more than the amount calculated based on the area of ​​the surface of the silica powder that can be covered by the surface treatment agent. The degree of hydrophobization of the hydrophobic silica powder of component (D) is preferably such that the surface carbon content (carbon content: mass %) of the hydrophobic silica powder as a whole after treatment is in the range of 0.1 to 20 mass %, and more preferably in the range of 0.5 to 10 mass %. If the surface carbon content is less than 0.1 mass %, it will be difficult to mix evenly with component (A). If the surface carbon content exceeds 20 mass %, the cured product of the composition will not have sufficient mechanical strength. In the present invention, the surface carbon content is a value obtained by measuring by a well-known elemental analysis method. In the case of the hydrophobic silica powder of component (D) having alkenyl groups on its surface carbon after treatment, the amount of the surface alkenyl groups is preferably 1.0×10 -3 ~2.0×10 -2 mol / 100g, and preferably 1.5×10 -3 ~1.5×10 -2 mol / 100g. If the surface olefin group content exceeds 2.0×10 -2 When the amount of the surface alkenyl group is less than 10 mol / 100 g, it may be difficult to uniformly mix with the component (A). In the present invention, the surface alkenyl group amount is a value obtained by FT-IR measurement. Furthermore, unless the aforementioned various silica powders are hydrophobic silica powders with a surface hydrophobic treatment (i.e., untreated hydrophilic silica powders without a surface hydrophobic treatment), the rubber properties of the cured product cannot be sufficiently improved, and excellent liquid injection molding (LIMS) moldability or mold releasability cannot be exhibited. Furthermore, the hydrophobic silica powder of component (D) must have a specific surface area of ​​50 m³ / min as measured by the BET method in order to improve the mechanical strength (rubber hardness, tensile strength, tear strength, elongation at break) of the cured product. 2 / g or more, preferably 100m 2 / g or more. On the other hand, the thickening of the composition when mixing with silica powder will become greater, making it difficult to mix. Therefore, 300 m 2 / g or less. Furthermore, the bulk density of the hydrophobic silica powder (component (D)) is 30-180 g / L, preferably 40-150 g / L. If the bulk density of the hydrophobic silica powder is less than 30 g / L, the viscosity of the composition increases, making it difficult to prepare. If it exceeds 180 g / L, sufficient reinforcing effect may not be achieved. In the present invention, the bulk density is a value measured by, for example, the tapping method. The hydrophobic silica powder of the component (D) may be used alone or in combination of two or more. The amount of aqueous silica powder (component (D)) is 10 to 40 parts by mass, preferably 15 to 30 parts by mass, relative to 100 parts by mass of component (A). If the amount is less than 10 parts by mass, no improvement in mechanical strength can be observed. If the amount is greater than 40 parts by mass, the viscosity increases significantly, making the formulation difficult. [Component (E)] Component (E) is a hydrosilylation reaction inhibitor and is an optional component formulated as needed. Examples of hydrosilylation addition reaction inhibitors include acetylene alcohols such as 1-ethynyl-1-cyclohexanol (also known as 1-ethynyl-1-hydroxycyclohexane), 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, and phenylbutynol; or a reaction product of a chlorosilane having a perfluoroalkyl group represented by the general formula (4) or a perfluorooxyalkyl group represented by the general formulas (5) and (6) and an acetylene alcohol; 3-methyl-3-pentene-1-yne, 3,5-dimethyl-3-hexene-1-yne, triallyl isocyanate, or polyvinylsiloxane and an organic phosphorus compound. By adding such an inhibitor, curing reactivity and storage stability can be appropriately maintained. The component (E) may be used alone or in combination of two or more. The amount of component (E) may be freely selected without prejudice to the object of the present invention. However, when component (E) is added, the amount is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of component (A). If the amount is too low, workability may be poor (sufficient shelf life and usable period may not be achieved), while if the amount is too high, the curability of the composition may be reduced. [Other Ingredients] The thermosetting perfluoropolyether rubber composition of the present invention may, in addition to the aforementioned components (A) to (E), optionally contain fillers other than component (D), adhesive agents (adhesion enhancers) that impart self-adhesion to the cured product of the composition, plasticizers, viscosity modifiers, flexibility enhancers, inorganic pigments such as titanium oxide, iron oxide, carbon black, and cobalt aluminate, heat resistance enhancers such as titanium oxide, iron oxide, carbon black, cerium oxide, cerium hydroxide, zinc carbonate, magnesium carbonate, and manganese carbonate, thermal conductivity enhancers such as aluminum oxide, boron nitride, silicon carbide, and metal powder, and electrical conductivity enhancers such as carbon black, silver powder, and conductive zinc white, to enhance the practicality of the composition. The amounts of these additives may be arbitrary, provided they do not impair the intended purpose of the present invention. [Adhesion enhancer (adhesion improver)] The adhesion enhancer is an organopolysiloxane having, in one molecule, a hydrogen atom directly bonded to a silicon atom, a perfluoroalkyl group or a perfluorooxyalkyl group, and an epoxy group or a trialkoxysilyl group bonded to a silicon atom via a divalent hydrocarbon group which may contain an oxygen atom, or both. The adhesion enhancer functions as an adhesion imparting agent that imparts self-adhesion to the cured product obtained after curing the composition of the present invention. The perfluoroalkyl group or perfluorooxyalkyl group is introduced from the viewpoints of compatibility with the component (A), dispersibility, and uniformity after curing. Examples of the perfluoroalkyl group or perfluorooxyalkyl group include groups represented by the general formulas (4) to (6). Furthermore, the perfluoroalkyl group or perfluorooxyalkyl group is preferably linked to the silicon atom constituting the polysiloxane via a divalent hydrocarbon group (linking group) which may contain at least one selected from a silicon atom, an oxygen atom, and a nitrogen atom. The divalent hydrocarbon group may be an alkylene group, an arylene group, or a combination thereof, or a structure in which one or more types of diorganosilylene groups selected from the group consisting of an ether bond oxygen atom, an amide bond, a carbonyl bond, an ester bond, and a dimethylsilylene group are inserted into such a group. For example, the following groups having 2 to 12 carbon atoms may be mentioned: (However, Me is a methyl group, Et is an ethyl group, iPr is an isopropyl group, Ph is a phenyl group, and Ph' is a phenylene group.) Furthermore, in the above-described structure, it is preferred that the left-side bonding portion is bonded to the silicon atom constituting the polysiloxane, and the right-side bonding portion is bonded to a perfluoroalkyl group or a perfluorooxyalkyl group. The organopolysiloxane is preferably a cyclic organopolysiloxane represented by the following general formula (17). (wherein, θ is an integer of 1 to 6, preferably an integer of 1 to 5, ι is an integer of 1 to 4, preferably an integer of 1 to 3, κ is an integer of 1 to 4, preferably an integer of 1 to 3, θ+ι+κ is an integer of 4 to 10, preferably an integer of 4 to 8. Moreover, R 9Each of the following groups is independently an unsubstituted or substituted monovalent hydrocarbon group; each of the following groups is independently a perfluoroalkyl group or a perfluorooxyalkyl group bonded to a silicon atom via a divalent hydrocarbon group which may contain at least one selected from a silicon atom, an oxygen atom, and a nitrogen atom; each of the following groups is independently an epoxy group or a trialkoxysilyl group bonded to a silicon atom via a divalent hydrocarbon group which may contain an oxygen atom. However, -(SiO)(H)R 9 -、-(SiO)(T)R 9 -, and -(SiO)(G)R 9 -The bonding order is not limited) In the above general formula (17), R 9 Each of the unsubstituted or substituted monovalent hydrocarbon groups is independently an unsubstituted or substituted monovalent hydrocarbon group, and examples thereof include the above-mentioned R 8 are the same groups, preferably methyl or ethyl. Furthermore, T is independently a perfluoroalkyl group or a perfluorooxyalkyl group bonded to a silicon atom via a divalent hydrocarbon group which may contain at least one selected from a silicon atom, an oxygen atom, and a nitrogen atom. Examples of such perfluoroalkyl groups or perfluorooxyalkyl groups include those represented by the aforementioned general formulas (4) to (6). Examples of such divalent hydrocarbon groups which may contain at least one selected from a silicon atom, an oxygen atom, and a nitrogen atom include the aforementioned alkylene groups, arylene groups, and combinations thereof, or structures in which one or more types selected from the group consisting of an ether bond oxygen atom, an amide bond, a carbonyl bond, an ester bond, and a dimethylsilylene group are inserted into such groups. Furthermore, G is independently an epoxy group or a trialkoxysilyl group bonded to a silicon atom via a divalent hydrocarbon group which may contain an oxygen atom. Examples of such epoxy groups include those represented by the following general formula (18) or alicyclic epoxy groups represented by the general formula (19) described later. In the above general formula (18), R 10 It is a divalent hydrocarbon group preferably having 1 to 10 carbon atoms (more preferably 1 to 5 carbon atoms) which may contain an oxygen atom (particularly an ether bond oxygen atom), a carbonyl bond or an ester bond. Specific examples include methylene, alkylene groups such as ethylene, propylene, butylene, hexylene and octylene, cycloalkylene groups such as cyclohexylene, oxyalkylene groups such as oxyethylene, oxypropylene and oxybutylene, and the following structure: -CH 2CH 2CH 2OCH 2-、 -CH 2CH 2CH 2OCO-et al. Specific examples of such epoxy groups include the following. Furthermore, the alicyclic epoxy group is preferably an epoxycyclohexyl group represented by the following formula (19). (Where R 10 Same as above) Specific examples of such epoxycyclohexyl groups include the following. On the other hand, examples of the trialkoxysilyl group include those represented by the following general formula (20). In the above general formula (20), R 11 It is preferably a divalent hydrocarbon group having 1 to 10 carbon atoms (more preferably 1 to 5 carbon atoms), and specifically includes alkylene groups such as methylene, ethylene, propylene, butylene, hexylene, cyclohexylene, and octylene. 12 Preferred are monovalent hydrocarbon groups having 1 to 8 carbon atoms (more preferably 1 to 4 carbon atoms), and specific examples thereof include alkyl groups such as methyl, ethyl, and n-propyl. Specific examples of such trialkoxysilyl groups include those shown below. (However, Me is methyl and Et is ethyl) Examples of such adhesive aids include the following compounds. Here, Me represents a methyl group, and Et represents an ethyl group. Furthermore, the arrangement of the siloxane units is random. (wherein, f" is an integer from 1 to 10, and g" is an integer from 1 to 50) The adhesion aid may be used alone or in combination of two or more. Furthermore, when the adhesion aid is used, the amount thereof is preferably in the range of 0.01 to 20 parts by mass, more preferably 0.01 to 10 parts by mass, and even more preferably 0.01 to 8 parts by mass, relative to 100 parts by mass of component (A). If the amount is less than 0.01 parts by mass, sufficient adhesion may not be achieved. If the amount exceeds 20 parts by mass, the physical strength of the cured product obtained after the composition of the present invention is cured may be reduced. As plasticizers, viscosity modifiers, and flexibility imparting agents, non-reactive (non-functional) straight-chain polyfluorinated compounds represented by the following general formulas (21) and (22) that do not have functional groups (alkenyl and hydrosilyl groups) that participate in the hydrosilylation addition reaction in the molecule, and / or polyfluorinated monoalkenyl compounds represented by the following general formula (23) can be used. (In formula (21), J is C o F 2o+1 - (o is an integer of 1 to 3), w is an integer of 1 to 500, preferably an integer of 2 to 300) (In formula (22), J is the same as above, and x and y are each an integer of 0 to 300, preferably an integer of 0 to 150. However, the case where both x and y are 0 is excluded. Furthermore, z is an integer of 1 to 300, preferably an integer of 1 to 150. The repeating units may be randomly bonded to each other.) [In formula (23), m is an integer of 1 to 200, preferably an integer of 1 to 150, n is an integer of 1 to 3, U is a single bond, or -CH 2-, -OCH 2-、-CH 2OCH 2-or-CO-NR 13 -V-. [Still, the left end of each of these bases is C n F 2n The right end is bonded to the CH group. 13 is a hydrogen atom, methyl, phenyl or allyl group, and V is -CH 2-, a group represented by the following structural formula (24) or a group represented by the following structural formula (25). (It is a dimethylphenylsilylene group represented by the o-position, m-position, or p-position, with the left end bonded to a nitrogen atom and the right end bonded to a carbon atom. Me represents a methyl group) (The left end is bonded to a nitrogen atom, and the right end is bonded to a carbon atom. Me represents a methyl group) Specific examples of the linear polyfluorinated compound represented by the general formula (21) or (22) include the following. (w' is an integer from 1 to 200) (x' is an integer of 1 to 200, and z' is an integer of 1 to 200. The repeating units may be randomly bonded to each other.) (y' is an integer of 1 to 200, z' is an integer of 1 to 200. The repeating units may be randomly bonded to each other) The linear polyfluorinated compound represented by the general formula (21) or (22) may be used alone or in combination of two or more. Specific examples of the polyfluoromonoalkenyl compound represented by the general formula (23) include the following. (Here, m' is an integer from 1 to 200. Me represents a methyl group) The polyfluoromonoalkenyl compound represented by the general formula (23) may be used alone or in combination of two or more. The amounts of these additives are arbitrary without prejudice to the purpose of the present invention. The thermosetting perfluoropolyether rubber composition of the present invention can be prepared by uniformly mixing the specified amounts of the above-mentioned (A) to (D) components, the required (E) component and other components by a well-known method, and it is particularly preferable to prepare it according to the following method. First, a machine such as a planetary mixer or a kneader is used to mix the specified amounts of the (A) component and the (D) component. When performing such preparation, there is no problem even at room temperature, but for the purpose of stabilizing shear heat, etc., it can be heated within a temperature range where the polymer does not decompose, and the condition is preferably 100~300℃ for about 10 minutes to 8 hours. Next, the mixture is cooled to room temperature and then treated (mixed) at room temperature (25℃±10℃) using a machine such as a 3-roll mill. Next, a predetermined amount of component (C) is added to the resulting kneaded product using a planetary mixer or the like, and kneading is performed at room temperature for 1 to 120 minutes. Furthermore, a predetermined amount of component (E) and other optional components, as required, are added and kneaded at room temperature for 1 to 120 minutes. Then, a predetermined amount of component (B) is added and kneaded at room temperature for 1 to 120 minutes to prepare a thermosetting perfluoropolyether rubber composition. The thermosetting perfluoropolyether rubber composition of the present invention can be formed by conventional methods, but the most suitable method or means for the purpose can also be selected from injection molding, transfer molding, injection molding, compression molding, extrusion molding, coating, etc. In particular, the thermosetting perfluoropolyether rubber composition of the present invention is a low-viscosity liquid before curing and has excellent injection molding and mold release properties, so it is preferably formed by injection molding. In this case, as the curing condition of the thermosetting perfluoropolyether rubber composition, it can be cured by heating at a temperature of 100-200°C (particularly 110-190°C, especially 120-170°C) for 0.1-30 minutes (particularly 1-30 minutes, especially 5-20 minutes). Furthermore, if necessary, secondary vulcanization (post-curing) can be performed at 100-230°C for about 1-24 hours. The cured product of the thermosetting perfluoropolyether rubber composition of the present invention obtained in this manner has excellent heat resistance, chemical resistance, solvent resistance, low temperature characteristics and rubber properties (mechanical strength, elongation, etc.). Therefore, it can be suitably used in diaphragms such as diaphragms for fuel regulators, diaphragms for pulsation suppressors, diaphragms for oil pressure switches, diaphragms for EGR, valves such as tank valves, power control valves, O-rings such as quick connectors, O-rings for syringes, or sealing materials such as oil seals and cylinder head gaskets for chemical equipment; specifically, diaphragms for pumps, valves, O-rings, hoses, seals, oil seals, Sealing materials such as gaskets, rubber parts for inkjet printers, and rubber parts for semiconductor manufacturing lines; specifically, diaphragms, valves, O-rings, seals, and gaskets for machines that come into contact with chemicals, valves that require low friction and wear resistance, and rubber parts for analytical and scientific machines; specifically, diaphragms, valves, and sealing parts (O-rings, seals, etc.) for pumps, and rubber parts for medical machines; specifically, applications for pumps, valves, joints, etc., or covering film materials, sealants, molded parts, extruded parts, covering materials, photocopier roller materials, moisture-proof coating materials for electrical appliances, potting materials for sensors, sealing materials for fuel cells, and laminated rubber cloth. [Examples] Hereinafter, the present invention will be described in detail with reference to synthesis examples, embodiments, and comparative examples. However, the present invention is not limited to the following embodiments. In the following exemplary formulas, Me is a methyl group. In the following examples, the amount of alkenyl groups and the amount of SiH groups contained are determined by 1 The measurement was performed by H-NMR. Room temperature refers to 25°C. The components (A) to (E) used in the following Examples and Comparative Examples are shown below. (A) Component (A-1): a perfluoropolyether polymer represented by the following formula (p1+q1=120, p1:q1=48:52, alkenyl content: 0.017 mol / 100 g) (A-2): Perfluoropolyether polymer represented by the following formula (p1+q1=90, p1:q1=48:52, alkenyl content: 0.023 mol / 100 g) (A-3): Perfluoropolyether polymer represented by the following formula (p1+q1=35, p1:q1=48:52, alkenyl content: 0.053 mol / 100 g) (A-4): Perfluoropolyether polymer represented by the following formula (r1=120, alkenyl content: 0.0098 mol / 100 g) (A-5): Perfluoropolyether polymer represented by the following formula (qs1+qs2=58, alkenyl content: 0.0097 mol / 100 g) (A-6): Perfluoropolyether polymer represented by the following formula (p1+q1=120, p1:q1=48:52, alkenyl content: 0.018 mol / 100 g) (A-7): Perfluoropolyether polymer represented by the following formula (p1+q1=120, p1:q1=48:52, alkenyl content: 0.017 mol / 100 g) (A-8): Perfluoropolyether polymer represented by the following formula (p1+q1=120, p1:q1=48:52, alkenyl content: 0.036 mol / 100 g) (A-9): Perfluoropolyether polymer represented by the following formula (p1+q1=120, p1:q1=48:52, alkenyl content: 0.034 mol / 100 g) (A-10): an alkenyl-containing polymer represented by the following formula (a1+b1=120, a1:b1=1:1, alkenyl content: 0.0092 mol / 100 g) (A-11): an alkenyl-containing polymer represented by the following formula (a1+b1=100, a1:b1=1:1, alkenyl content: 0.012 mol / 100 g) (A-12): an alkenyl-containing polymer represented by the following formula (a1+b1=35, a1:b1=1:1, alkenyl content: 0.030 mol / 100 g) (B) Component (B-1): a compound represented by the following formula (SiH group content: 0.0050 mol / g) (C) Component (C-1): Toluene solution of platinum-divinyltetramethyldisiloxane complex (platinum concentration 0.5% by mass) (D) Component (D-1): A-130 (Nippon Aerosil Co., Ltd., hydrophilic fumed silica) treated with a mixed treatment agent of hexamethyldisilazane and 1,3-divinyl-1,1,3,3-tetramethyldisilazane to obtain a hydrophobic fumed silica (BET specific surface area: about 200 m 2 / g, surface carbon content (carbon content): about 5.0% by mass, surface vinyl content: 3.00×10 -3 mol / 100g, bulk density: about 50g / L) (D-2): R-972 (manufactured by Nippon Aerosil Co., Ltd., hydrophobic fumed silica with a surface hydrophobic treatment using dimethyldichlorosilane. BET specific surface area: about 110m 2 / g, surface carbon content (carbon content): 0.6~1.2% by mass, bulk density: about 50g / L) (D-3): R-974 (manufactured by Nippon Aerosil Co., Ltd., a hydrophobic fumed silica whose surface is hydrophobized with dimethyldichlorosilane. BET specific surface area: about 170m 2 / g, surface carbon content (carbon content): 0.9~1.5% by mass, bulk density: about 50g / L) (D-4): R-976 (manufactured by Nippon Aerosil Co., Ltd., a hydrophobic fumed silica whose surface is hydrophobized with dimethyldichlorosilane. BET specific surface area: about 250m 2 / g, surface carbon content (carbon content): about 1.5% by mass, bulk density: about 50 g / L) (D-5): R-8200 (manufactured by Nippon Aerosil Co., Ltd., hydrophobic fumed silica whose surface is hydrophobized with hexamethyldisilazane. BET specific surface area: about 160 m 2 / g, surface carbon content (carbon content): about 2.0 to 4.0% by mass, bulk density: about 140 g / L) (D-6): A-130 (manufactured by Nippon Aerosil Co., Ltd., hydrophilic fumed silica. BET specific surface area: about 130 m 2 / g, bulk density: about 50g / L) (D-7): A-200 (manufactured by Nippon Aerosil Co., Ltd., hydrophilic fumed silica. BET specific surface area: about 200m 2 / g, bulk density: about 50g / L) (D-8): A-300 (manufactured by Nippon Aerosil Co., Ltd., hydrophilic fumed silica. BET specific surface area: about 300m 2 / g, bulk density: about 50g / L) (E) Component (E-1): 50% by mass toluene solution of 1-ethynyl-1-hydroxycyclohexane [Examples 1-17, Comparative Examples 1-13] In Examples 1-17 and Comparative Examples 1-13, compositions were prepared as follows using the specified amounts of the components shown in Tables 3-6. Furthermore, these compositions were shaped and cured according to the following method to produce cured products, which were then evaluated for tensile strength, elongation at break, LIMS formability, and mold release properties. < Modulation of the composition of Examples 1 to 17 and Comparative Examples 1 to 13 > First, the (A) component and the (D) component were mixed at 120 ° C for 1 hour using a planetary mixer according to the specified amounts shown in Tables 3 to 6. After the mixture was cooled to room temperature, it was subjected to 2 times of 3-roll mill treatment at room temperature. For 130 parts by mass of the obtained mixture, the specified amount of (C) component as shown in Tables 3 to 6 was added, and the mixture was mixed at room temperature for 10 minutes using a planetary mixer. Further, the specified amount of (E) component as shown in Tables 3 to 6 was added, and the mixture was mixed at room temperature for 10 minutes using a planetary mixer, and then the specified amount of (B) component as shown in Tables 3 to 6 was added, and the mixture was mixed at room temperature for 10 minutes using a planetary mixer to obtain a composition. Moreover, the (B) component was added in such a manner that [SiH group of (B) component / alkenyl group of (A) component] = 1.2 (molar ratio) was obtained. <Preparation of Cured Products of Examples 1-17 and Comparative Examples 1-13> The compositions of Examples 1-17 and Comparative Examples 1-13 were press-crosslinked at 150°C for 10 minutes (primary crosslinking) to form 2.0 mm thick rubber sheets. Furthermore, they were oven-crosslinked at 200°C for 4 hours (secondary crosslinking) to produce cured products. <Tensile Strength of Cured Products> The tensile strength of the cured products of Examples 1 to 17 and Comparative Examples 1 to 13 was measured in accordance with JIS K6249 and evaluated based on the following criteria. The results are shown in Tables 3 to 6. [Evaluation Criteria] ◎: 10.0 MPa or greater ○: 7.0 MPa or greater but less than 10.0 MPa △: 4.0 MPa or greater but less than 7.0 MPa ×: less than 4.0 MPa <Elongation at Cutting of Cured Materials> The elongation at cutting of the cured materials of Examples 1 to 17 and Comparative Examples 1 to 13 was measured in accordance with JIS K6249 and evaluated based on the following criteria. The results are shown in Tables 3 to 6. [Evaluation Criteria] ◎: 300% or more ○: 200% or more but less than 300% △: 100% or more but less than 200% ×: less than 100% <LIMS formability and mold releasability> Using an injection molding machine (10-ton LIMS molding machine NS-10 LIMS specification manufactured by Nissei Plastics Co., Ltd.) and a 9-cavity mold for an O-ring (size 214), with reference to Japanese Patent Publication No. 2005-24695 (Patent Document 3), an O-ring (size 214) was molded according to the injection molding conditions shown in Table 1. The formability of each component was evaluated based on the following four stages. LIMS formability consists of two evaluation items: "injection formability" during the molding process and "molded product appearance" of the molded product just completed, and evaluation criteria are set as shown in Table 2 below. Furthermore, as mold releasability, the ease of removing the O-ring from the mold was evaluated based on the criteria shown below. The results are shown in Tables 3 to 6. <Evaluation criteria for mold releasability> ◎: Very good ○: Good △: Slightly good ×: Difficult

Claims

1. A thermosetting perfluoropolyether rubber composition comprising the following components (A) to (D): (A) a perfluoropolyether polymer having at least two alkenyl groups in its molecular chain as represented by the following general formula (1) or (2): 100 parts by weight, [wherein, Rf is a perfluoropolyoxyalkylene group represented by the following general formula (3)] (In the formula, p, q, r, s, t, and u are independent integers from 0 to 450, and p+q+r+s+t+u is an integer from 20 to 450. The arrangement of each fluoroalkyl unit enclosed in parentheses labeled p, q, r, s, t, and u can be block or random. v is an independent integer from 1 to 3 in each unit); L is an independent single bond, or an oxygen atom, a sulfur atom, or a divalent organogroup; M is an independent single bond, or an organogroup containing a nitrogen atom, a silicon atom, a carbon atom, a phosphorus atom, or such an organogroup, or a 2-8 valent organogroup; W is an independent alkenyl group or a 1-valent organogroup with an alkenyl group at the end; a is an independent integer from 1 to 7; Q is an independent single bond or a 2-valent organogroup; Y is an independent 2-valent organogroup with an alkenyl group; b is an independent integer from 1 to 10; B is an independent hydrogen atom, an alkyl group with 1 to 4 carbon atoms, or a halogen atom.) (B) Fluorinated organic hydrogenated polysiloxane with two or more hydrogen atoms bonded to silicon atoms in one molecule: the amount of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) is 0.5 to 5 moles relative to 1 mole of alkenyl group in component (A); (C) Hydrosilicification reaction catalyst: amount of catalyst; (D) Hydrophobic silica powder with a BET specific surface area of ​​50 m² / g or more: 10 to 40 parts by mass.

2. The thermosetting perfluoropolyether rubber composition as claimed in claim 1, wherein, In formulas (1) and (2) of component (A), Rf is a perfluoropolyoxyalkylene group represented by the following general formula (3'), (where p, q, r, s and v are the same as above, and p+q+r+s are integers from 20 to 450, and each fluoroalkylene unit enclosed in parentheses marked p, q, r, s can be block or random).

3. The thermosetting perfluoropolyether rubber composition as claimed in claim 1, wherein, (D) The hydrophobic silica powder is prepared by surface hydrophobization treatment using an organosilicone compound selected from at least one of organochlorosilanes, organoalkoxysilanes, organodiasilazanes and cyclic organopolysilazanes.

4. The thermosetting perfluoropolyether rubber composition as claimed in claim 1, wherein, (D) The surface carbon content of the hydrophobic silica powder is 0.1 to 20% of the total mass of the hydrophobic silica powder.

5. The thermosetting perfluoropolyether rubber composition as claimed in claim 1, wherein, It further contains (E) hydrosilicification reaction inhibitors.

6. The thermosetting perfluoropolyether rubber composition of any one of claims 1 to 5 is for injection molding.

Images