Millable type fluorosilicone rubber composition, and rubber component for engine periphery of transport plane

Abstract

To provide a millable type fluorosilicone rubber composition which gives a cured product excellent in amine resistance and heat resistance.SOLUTION: A millable type fuluorosilicone rubber composition includes: (A) 100 pts.mass of a crude rubber-like organopolysiloxane expressed by the following formula (1) (where in the formula, R1 is independently a group selected from the group consisting of a 1-10C alkyl group, a 6-10C aryl group, and a 7-10C aralkyl group, R2 is a 2-8C alkenyl group, a and b are respectively integers of 1 or greater, c is an integer of 0 or greater, a+b+c=2,000 to 6,000, a / (a+b+c)=0.3 to 0.8, and siloxane unit bonds in a, b, and c brackets may be brock or random); (B) 10-100 pts.mass of a reinforcing silica having a specific surface area by a BET method of 50 m2 / g or more; and (C) a catalytic amount of an organic peroxide.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to millable-type fluorosilicone rubber compositions and rubber parts for use around transport engines, which are made from cured products of said fluorosilicone rubber compositions. [Background technology]

[0002] Fluorosilicone rubber compositions based on fluorosilicone crude rubber containing 3,3,3-trifluoropropyl groups as side-chain substituents exhibit excellent solvent resistance in addition to the properties of dimethylsilicone rubber. As a result, they are widely used in transportation equipment and petroleum-related equipment components such as diaphragms, O-rings, and oil seals. Meanwhile, amines such as various polyether amines, alcohol amines, and alkyl amines are added to gasoline fuels and oils as antioxidants and rust inhibitors. Although fluorosilicone rubber has excellent solvent resistance, these amines cause cracking of the siloxane backbone. Therefore, even fluorosilicone rubbers cannot maintain the initial physical properties of molded products when they come into contact with amines.

[0003] To address this issue, Patent Document 1 discloses a method for preventing degradation caused by antioxidants by adding an anti-extraction buffer to fluorosilicone rubber. Patent Document 2 discloses improving fuel resistance by using an organopolysiloxane containing a perfluoroalkyl ether group having four or more carbon atoms as the base polymer. Patent Document 3 discloses a method for improving alcohol fuel resistance by adding titanium dioxide and triallyl isocyanurate with an average particle size of 0.1 to 1.0 μm to a fluorosilicone polymer having an unsaturated group at at least one end. Patent Document 4 discloses a method for improving amine resistance by adding at least one chloride selected from alkali metal chlorides, alkaline earth metal chlorides, and ammonium chloride to a fluorosilicone rubber composition.

[0004] However, even with these methods, it has been difficult to sufficiently prevent cracking of fluorosilicone rubber when it comes into contact with amines.

[0005] In addition, in recent years, the Ministry of the Environment has placed organic fluorine compounds on its list of "items requiring monitoring for the protection of human health." As a result, compounds containing perfluoroalkyl groups such as PFOS have been restricted, meaning that long-chain fluoroalkyl groups can no longer be used as modifying groups in fluorosilicone rubber. As a result, alternative materials are being sought. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-252421 [Patent Document 2] Japanese Patent Application Publication No. 5-186700 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-26735 [Patent Document 4] Japanese Patent Application Publication No. 2017-222796 Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide a millable-type fluorosilicone rubber composition that produces a fluorosilicone rubber (cured product) with good heat resistance and minimal deterioration in physical properties even when it comes into contact with amine-based antioxidants contained in fuel, and to provide rubber parts for use around the engines of transport aircraft, which are made from the cured fluorosilicone rubber.

[0008] In addition, a millable composition means a composition that is non-liquid (paste or solid) with no self-fluidity at room temperature (25°C) and can be mixed uniformly under shear stress using a kneading means such as a roll mill. [Means for solving the problem]

[0009] The present invention has been made to solve the above problems, (A) The following formula (1) [ka] (In the formula, R 1 are independently selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms; R 2 is an alkenyl group having 2 to 8 carbon atoms, a and b are each an integer of 1 or more, c is an integer of 0 or more, a+b+c=2,000 to 6,000, and a / (a+b+c)=0.3 to 0.8. The siloxane units bounded by a, b, and c may be bonded in either a block or random fashion. 100 parts by mass of a raw rubber-like organopolysiloxane represented by the formula: (B) The specific surface area by BET method is 50m 2 / g or more reinforcing silica: 10 to 100 parts by mass, (C) Organic peroxide: catalytic amount, The present invention provides a millable fluorosilicone rubber composition comprising:

[0010] The millable fluorosilicone rubber composition of the present invention is able to produce fluorosilicone rubber molded articles (cured products) that exhibit little deterioration in physical properties even when in contact with amine-based antioxidants and have good heat resistance.

[0011] The present invention also provides a rubber part for use around the engine of a transport vehicle, which is made from a cured product of the above-mentioned millable-type fluorosilicone rubber composition.

[0012] Rubber parts for use around transport engines made from a cured product of the millable-type fluorosilicone rubber composition of the present invention are preferred because they exhibit little deterioration in physical properties even when in contact with amine-based antioxidants contained in gasoline fuels and oils. [Effects of the Invention]

[0013] The millable-type fluorosilicone rubber composition of the present invention shows little deterioration in physical properties even when it comes into contact with amine-based antioxidants, and in particular, changes in tensile strength, elongation at break, and compression set are suppressed. It also produces fluorosilicone rubber molded articles (cured products) with good heat resistance, making these fluorosilicone rubber molded articles particularly suitable for applications such as rubber parts around transportation engines. Furthermore, while long-chain fluoroalkyl groups can no longer be used as modifying groups in fluorosilicone rubber due to restrictions on perfluoroalkyl group-containing compounds such as PFOS, the fluorosilicone rubber molded articles of the present invention do not impose a burden on the environment and are not subject to these restrictions. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention was made to solve the above problems, and was completed based on the discovery that a structure in which a fluorophenyl group is contained within the siloxane unit, instead of the 3,3,3-trifluoropropylmethylsiloxane unit that constitutes the fluorosilicone polymer main chain, can prevent the deterioration of the physical properties of fluorosilicone rubber due to contact with amine-based antioxidants, etc.

[0015] The present invention will be described in detail below, but the present invention is not limited thereto.

[0016] [Component (A)] In the present invention, component (A) is a main component in a millable silicone rubber composition, The following formula (1) [ka] (In the formula, R 1 are independently selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms; R 2is an alkenyl group having 2 to 8 carbon atoms, a and b are each an integer of 1 or more, c is an integer of 0 or more, a+b+c=2,000 to 6,000, and a / (a+b+c)=0.3 to 0.8. The siloxane units bounded by a, b, and c may be bonded in either a block or random fashion. It is a crude rubber-like organopolysiloxane represented by the formula:

[0017] Here, raw rubber refers to a high polymer that is either a very viscous liquid at room temperature (25°C) or a non-liquid (paste or solid) that does not have self-flowing properties.

[0018] Here, in the above formula (1), R 1 are independently selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms. 1 Each of the R groups preferably has 8 or less carbon atoms. 1 Specific examples of R include alkyl groups such as methyl, ethyl, isopropyl, and butyl groups, cycloalkyl groups such as cyclohexyl and cyclopentyl groups, aryl groups such as phenyl, tolyl, and xylyl groups, and aralkyl groups such as benzyl and phenylethyl groups. 1 is particularly preferably a methyl group, an ethyl group, or a phenyl group.

[0019] R 2 R is an alkenyl group having 2 to 8 carbon atoms. Specific examples thereof include a vinyl group and an allyl group. 2 A vinyl group is particularly preferred.

[0020] Furthermore, in the formula (1), a and b are each an integer of 1 or more, and c is an integer of 0 or more, where a+b+c=2,000 to 6,000, and a / (a+b+c)=0.3 to 0.8.

[0021] If a+b+c is less than 2,000, the viscosity will be low and the adhesiveness will increase, significantly impairing the processability of Millable Rubber. Conversely, if it exceeds 6,000, the viscosity will be high, making subsequent addition and compounding difficult.

[0022] Furthermore, a / (a+b+c) is 0.3 to 0.8, and a / (a+b+c) is preferably 0.3 to 0.7. If it is less than 0.3, sufficient oil resistance cannot be obtained. If it exceeds 0.8, the flexibility of the cured product may decrease, and the tensile strength, tear strength, and elongation at break may become insufficient.

[0023] Furthermore, b / (a+b+c) is preferably 0.1 to 0.3. If it is 0.1 or more, crosslinking will proceed sufficiently, resulting in a product with sufficient hardness and heat resistance. If it is 0.3 or less, the cured product will not become brittle.

[0024] In the organopolysiloxane of the present invention, R 2 Each molecule may contain three or more R groups, and the content of R groups is preferably 0.01 to 1 mol % relative to the number of silicon atoms in the molecule. 2 It is particularly preferable that R is contained in an amount of 0.02 to 0.5 mol %. 2 It is particularly preferred that R is a vinyl group. 2 If the content is 1 mol % or less, the rubber hardness becomes appropriate, the rubber does not become brittle, and the mechanical strength such as tensile strength and tear strength becomes sufficient.

[0025] The organopolysiloxane represented by the above formula (1) can be prepared, for example, from a compound represented by the following formula (2): [ka] This can be obtained by ring-opening polymerization of a fluorophenylsiloxane cyclic trimer using a siloxane oligomer represented by the following formula as an initiator. Specifically, it is obtained by adding an appropriate amount of the above siloxane oligomer to a cyclic organosiloxane and carrying out living polymerization under sealed conditions at 100°C to 150°C. By adjusting the amount of the above siloxane oligomer during living polymerization, an organopolysiloxane that has reached the desired degree of polymerization can be obtained.

[0026] The degree of polymerization of the organopolysiloxane is 2,000 to 6,000, preferably 2,000 to 5,500. A degree of polymerization of 2,000 to 5,000 is particularly preferred. The organopolysiloxane is characterized by its lack of self-flowability at room temperature (25°C), being in the form of raw rubber. If the degree of polymerization is less than 2,000, the viscosity decreases, the stickiness increases, and the processability of the millable rubber is significantly impaired. Conversely, if the degree of polymerization exceeds 6,000, the viscosity increases, making subsequent addition and blending difficult.

[0027] The degree of polymerization in the present invention is determined as a weight-average degree of polymerization from the weight-average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC) analysis under the following conditions. [Measurement conditions] Developing solvent: tetrahydrofuran (THF) Flow rate: 0.6mL / min Detector: Refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperH4000(6.0mmI.D.×15cm×1) TSKgel SuperH3000(6.0mmI.D.×15cm×1) TSKgel SuperH2000(6.0mmI.D.×15cm×2) (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 20 μL (0.5 wt% THF solution)

[0028] The component (A) may be a single type, or a mixture of two or more types with different molecular weights (degrees of polymerization) or molecular structures.

[0029] In the present invention, a crude rubber-like organopolysiloxane having D units substituted with fluorophenyl groups is used as the base polymer, and therefore it is possible to provide a fluorosilicone rubber that is not subject to regulations on perfluoroalkyl group-containing compounds, is less likely to crack even when in contact with amine-based antioxidants, and is able to sufficiently maintain its physical properties and have good heat resistance.

[0030] [(B) Component] The reinforcing silica of component (B) acts as a component that imparts excellent mechanical properties to the resulting millable fluorosilicone rubber composition. The reinforcing silica may be either precipitated silica (wet silica) or fumed silica (dry silica). In the present invention, the reinforcing silica has a specific surface area of ​​50 m2 as measured by the BET method. 2 / g or more. Reinforcing silica is 100 to 400m 2 / g is preferable. 2 If the silica content is less than 400m / g, the reinforcing effect of the reinforcing silica will be insufficient. 2 When the viscosity is not more than 1 / g, the viscosity does not become too high, and the moldability is therefore favorable.

[0031] The reinforcing silica of component (B) is preferably surface-treated. Reinforcing silica that has been surface-treated with an organosilicon compound such as a silanol-containing organopolysiloxane, organopolysilazane, chlorosilane, or alkoxysilane can be used. The timing of the surface treatment is arbitrary, as long as it is completed before the silicone rubber composition is obtained. The surface-treated reinforcing silica may be pre-treated or may be treated in situ by adding a surface treatment agent to untreated silica during the production of the silicone rubber composition. These reinforcing silicas may be used alone or in combination of two or more.

[0032] The amount of reinforcing silica (B) added is 10 to 100 parts by mass, preferably 15 to 80 parts by mass, and more preferably 20 to 70 parts by mass per 100 parts by mass of organopolysiloxane (A). If this amount exceeds 100 parts by mass, not only will the processability of the silicone rubber composition decrease, but the mechanical properties of the cured silicone rubber will also be insufficient. If the amount is less than 10 parts by mass, good mechanical properties will not be obtained.

[0033] [(C) component] The organic peroxide of component (C) is a curing agent that cures component (A), and is not particularly limited as long as it can cure component (A). Specific examples of organic peroxides include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, di-t-butyl peroxide, t-butyl perbenzoate, and 1,6-hexanediol-bis-t-butylperoxycarbonate.

[0034] The amount of organic peroxide blended is a catalytic amount, preferably 0.1 to 10 parts by mass, per 100 parts by mass of component (A). A blend amount of 0.2 to 5 parts by mass is particularly preferred. When the blend amount is 0.1 part by mass or more per 100 parts by mass of component (A), sufficient curing is achieved, while when the blend amount is 10 parts by mass or less, discoloration of the cured silicone rubber due to decomposition residues of the organic peroxide is prevented.

[0035] [Other ingredients] In addition to the above components, the millable fluorosilicone rubber composition of the present invention may optionally contain fillers such as crushed quartz, crystalline silica, diatomaceous earth, calcium carbonate, etc., colorants, tear strength improvers, acid acceptors, thermal conductivity improvers such as alumina and boron nitride, mold release agents, various alkoxysilanes as dispersants for fillers, particularly phenyl group-containing alkoxysilanes and their hydrolysates, diphenylsilanediol, carbon functional silane, and other fillers and additives known in thermosetting silicone rubber compositions.

[0036] [Method of producing the composition] The millable fluorosilicone rubber composition of the present invention can be obtained by mixing the components that make up the composition in a known mixer such as a kneader, Banbury mixer, twin-roll mixer, etc. When a composition containing components (A) to (C) is used as the millable fluorosilicone rubber composition, it is preferable to first mix components (A) and (B) to obtain a mixture, and then add component (C) to the mixture.

[0037] When the composition containing the components (A) to (C) further contains other components, it is preferable to first mix the components (A), (B), and the other components to obtain a mixture, and then add the component (C) to the mixture.

[0038] When a surface-treated reinforcing silica is used as component (B), it can be mixed as is, but if the surface of component (B) is to be treated later, the timing of this treatment is optional. For example, a separate surface treatment step may be provided, or the surface treatment may be carried out by mixing component (B), other components such as component (A) (all or part thereof), and a surface treatment agent, and heating as necessary while mixing.

[0039] In this specification, the kneaded product before the addition of component (C) is sometimes referred to as the silicone base compound, and the millable fluorosilicone rubber composition after the addition of component (C) is sometimes referred to as the full compound.

[0040] [Curing conditions] The millable fluorosilicone rubber composition of the present invention can be cured by known curing methods under known curing conditions. Specifically, the composition can be cured by heating at a temperature of typically 25 to 200°C, preferably 80 to 160°C. The heating time may be about 0.5 minutes to 5 hours, and preferably about 1 minute to 3 hours. The millable fluorosilicone rubber composition of the present invention may be cured under pressure.

[0041] [Cured product] As described above, the composition of the present invention can be cured to give a cured product, which provides a fluorosilicone rubber molded article (cured product) that exhibits good heat resistance and minimal deterioration in physical properties even when exposed to amine-based antioxidants. The cured product of the composition of the present invention is suitable for rubber parts for use in the periphery of transport engines. Specific examples include turbo hoses, gaskets, O-rings, etc. Rubber parts for use in the periphery of transport engines made of such cured products are preferred because they exhibit little deterioration in physical properties even when in contact with amine-based antioxidants contained in gasoline fuels, oils, etc. [Example]

[0042] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0043] [Heat resistance] Cured products of the millable-type fluorosilicone rubber compositions prepared in the following examples and comparative examples were used to prepare test sheets in accordance with JIS K 6249:2003, and the initial values ​​of hardness, tensile strength (MPa), and elongation at break (%) were measured using these test sheets. The test sheets were then placed in a dryer at 200°C for 72 hours (3 days), after which the hardness, tensile strength (MPa), and elongation at break (%) were similarly measured. The Duro A hardness change rate and the elongation at break change rate (decrease rate) were calculated from the measured values ​​using the following formulas. In the present invention, hardness is a value measured using a Durometer A hardness tester.

[0044] Hardness change rate = {(Hardness after heating at 225°C for 72 hours) - (Initial hardness)} / (Initial hardness) x 100(%) Tensile strength change rate = {(initial tensile strength) - (tensile strength after heating at 225°C for 72 hours)} / (initial elongation at break) x 100(%) Rate of change in elongation at break = {(initial elongation at break) - (elongation at break after heating at 225°C for 72 hours)} / (initial elongation at break) x 100(%)

[0045] [Oil resistance measurement] The hardness and initial volume change (%) of the cured products of the millable fluorosilicone rubber compositions prepared in the following examples and comparative examples were measured in accordance with JIS K 6249:2003. The test sheets were immersed in IRM903 (manufactured by Japan San Oil) at 150°C for 70 hours, after which the hardness and volume change were measured. The results are shown in Table 1.

[0046] [Amine resistance measurement] For the millable fluorosilicone rubber compositions prepared in the following examples and comparative examples, the resulting full compounds were pressure-molded and cured at 165°C for 10 minutes, followed by post-curing at 200°C for 4 hours to prepare small cylindrical test pieces with a diameter of 13 mm and a height of 6.3 mm for measuring compression set. The initial compression set was measured according to JIS K 6262:2013. The test pieces were immersed in a 25% compressed state in a 1% by weight IRM903 solution of N,N'-di-sec-butyl-p-phenylenediamine or a 10% ethanol solution of N,N'-bis(salicylidene)-1,2-propanediamine at room temperature for 168 hours at 120°C, and then cooled to measure the compression set.

[0047] The following components were used as component (A): (A-1): Organopolysiloxane gum having the following formula: Number of vinyl groups per molecule: 18, 0.45 mol% relative to the number of silicon atoms in the molecule, and average degree of polymerization: 3,998 [ka]

[0048] (A-2): Organopolysiloxane gum having the following formula, the number of vinyl groups per molecule being 18 (0.45 mol % relative to the number of silicon atoms in the molecule), and an average degree of polymerization of 3,988. [ka]

[0049] The following components were used as component (B): (B):Specific surface area 130m 2 / g of dry silica (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil 130)

[0050] The following components were used as component (C): (C) 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane

[0051] [Example 1] To 100 parts by weight of component (A-1), 40 parts by weight of component (B) and 10 parts by weight of diphenylsilanediol as a surface treatment agent for component (B) were added and uniformly kneaded using a two-roll mill. The mixture was heat-treated at 150°C for 4 hours and then kneaded using a two-roll mill to obtain the base silicone base compound A1. To 100 parts by weight of the resulting base compound, 0.8 parts by weight of a paste containing 80% by weight of component (C) (equivalent to 0.64 parts by weight of component (C) per 100 parts by weight of component (A-1)) was added and uniformly mixed using a two-roll mill to obtain the full compound. Test sheets and cured products were prepared from the resulting composition, and various physical properties were evaluated. The results are shown in Table 1.

[0052] [Example 2] To 100 parts by weight of component (A-2), 40 parts by weight of component (B) and 10 parts by weight of diphenylsilanediol, a surface treatment agent for component (B), were added and uniformly kneaded. The mixture was then heat-treated at 150°C for 4 hours and then kneaded with a two-roll mill to obtain the base silicone base compound A2. To 100 parts by weight of the resulting base compound, 0.8 parts by weight of a paste containing 80% by weight of component (C) (equivalent to 0.64 parts by weight of component (C) per 100 parts by weight of component (A-1)) was added and uniformly mixed with a two-roll mill to obtain a full compound. Test sheets and cured products were prepared from the resulting composition, and various physical properties were evaluated. The results are shown in Table 1.

[0053] [Comparative Example 1] In Example 1, component (A-1) was replaced with organopolysiloxane gum (A-3) consisting of 99.85 mol% dimethylsiloxane units, 0.125 mol% methylvinylsiloxane units, and 0.025 mol% dimethylvinylsiloxy units (10 vinyl groups per molecule, 0.15 mol% relative to the number of silicon atoms per molecule), with an average degree of polymerization of 6,000. 10 parts by mass of diphenylsilanediol was added as a dispersant, and the mixture was uniformly kneaded. After heat treatment at 150°C for 4 hours, the mixture was kneaded using a two-roll mill to obtain the base silicone-based compound A3. Silicone rubber compositions were then prepared in the same manner. Test sheets and cured products were then prepared from the resulting compositions, and various physical properties were evaluated. The results are shown in Table 1.

[0054] Comparative Example 2 In Example 1, component (A-1) was replaced with the organopolysiloxane crude rubber (A-4) shown below, which had 16 vinyl groups per molecule, 0.395 mol% relative to the number of silicon atoms per molecule, and an average degree of polymerization of 4,023. 10 parts by mass of diphenylsilanediol was added as a dispersant, and the mixture was kneaded uniformly. After heat treatment at 150°C for 4 hours, the mixture was kneaded using a two-roll mill to obtain the base silicone-based compound A4. Silicone rubber compositions were then prepared in the same manner, and test sheets and cured products were prepared from the resulting compositions. Various physical properties were evaluated. The results are shown in Table 1. [ka]

[0055] Comparative Example 3 In Example 1, the component (A-1) was replaced with an organopolysiloxane raw rubber (A-5) represented by the following formula: the number of vinyl groups per molecule: 18 (0.30 mol % relative to the number of silicon atoms in the molecule) and the average degree of polymerization: 5990. [ka] The mixture was replaced with 10 parts by mass of diphenylsilanediol as a dispersant, and the mixture was kneaded uniformly. After heat treatment at 150°C for 4 hours, it was kneaded using a two-roll mill to obtain the base silicone-based compound A5. Silicone rubber compositions were then prepared in the same manner, and test sheets and cured products were made from the resulting compositions, and various physical properties were evaluated. The results are shown in Table 1. Comparative Example 4 In Example 1, the component (A-1) was replaced with an organopolysiloxane raw rubber (A-6) represented by the following formula: the number of vinyl groups per molecule: 16, 0.45 mol% relative to the silicon atoms in the molecule, and the average degree of polymerization: 4018. [ka] The mixture was replaced with 10 parts by mass of diphenylsilanediol as a dispersant, and the mixture was kneaded uniformly. After heat treatment at 150°C for 4 hours, it was kneaded using a two-roll mill to obtain the base silicone-based compound A6. Silicone rubber compositions were then prepared in the same manner, and test sheets and cured products were made from the resulting compositions, and various physical properties were evaluated. The results are shown in Table 1.

[0056] [Table 1]

[0057] As a result of heat resistance measurement, under the conditions of using oil containing an amine-based antioxidant, that is, a 1 mass % IRM903 solution of N,N'-di-sec-butyl-p-phenylenediamine or a 10% ethanol solution of N,N'-bis(salicylidene)-1,2-propanediamine, the compression set of Examples 1 and 2 was superior to that of the comparative example. That is, it is clear that Examples 1 and 2 show little deterioration in physical properties even when they come into contact with an amine-based antioxidant or the like, and have superior durability to the Comparative Example.

[0058] The present invention is not limited to the above-described examples. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included within the technical scope of the present invention.

Claims

1. (A) Formula (1) below 【Chemistry 1】 (In the formula, R １ are independently selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms; R ２ is an alkenyl group having 2 to 8 carbon atoms, a and b are each an integer of 1 or more, c is an integer of 0 or more, a+b+c=2,000 to 6,000, and a / (a+b+c)=0.3 to 0.

8. The siloxane units bounded by a, b, and c may be bonded in either block or random fashion. 100 parts by mass of a raw rubber-like organopolysiloxane represented by the formula: (B) A specific surface area measured by the BET method is 50 m ２ / g or more reinforcing silica: 10 to 100 parts by mass, (C) Organic peroxide: catalytic amount, A millable type fluorosilicone rubber composition comprising:

2. 2. A rubber part for use around the engine of a transport vehicle, comprising a cured product of the millable fluorosilicone rubber composition of claim 1.

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