Silicone rubber composition and application thereof

Abstract

The invention relates to the technical field of silicone rubber materials, in particular to a silicone rubber composition and application thereof. The silicone rubber composition provided by the invention comprises silicone rubber and fluorosilane modified fumed silica. The silicone rubber composition provided by the invention has excellent mechanical properties, cold resistance, oil resistance and damping performance, can be applied to shock absorbers, and is especially suitable for shock absorbers working in low-temperature and oily environments.

Description

Technical Field

[0001] The present application relates to the technical field of silicone rubber materials, and in particular to a silicone rubber composition and application thereof. Background Art

[0002] Silicone rubber is a semi-organic and semi-inorganic polymer with a silicon-oxygen inorganic structure as the main chain and organic groups as the side chains. Its unique structure gives it excellent weather resistance, high and low temperature resistance, and physiological inertness, and is widely used in automotive parts, kitchen and bathroom life, aerospace, and medical fields. However, silicone rubber has a slightly poor oil resistance. It will swell if immersed in non-polar solvents, various mineral oils, and fuel oils for a long time, and the mechanical properties will decrease due to the destruction of the silicone rubber network structure. Therefore, its application is subject to certain restrictions in some occasions involving non-polar solvents or oils.

[0003] In order to improve the oil resistance of silicone rubber, it is usually necessary to modify silicone rubber by mixing ethylene-vinyl acetate rubber (EVM), fluororubber (FKM) or acrylic rubber (ACM) with polar rubbers that have better oil resistance than silicone rubber. However, the modification by blending will greatly increase the glass transition temperature of the rubber, which will cause the low-temperature modulus of the rubber material to increase sharply. For shock absorbers used in frequency-sensitive components, the resonant frequency of the shock absorber needs to change as little as possible within the operating temperature range. However, the resonant frequency is positively correlated with the modulus of the material used. Therefore, the sharp increase in the modulus of the rubber material at low temperatures will cause the resonant frequency of the shock absorber to increase rapidly, thereby changing the vibration characteristics of the system, causing the shock absorber to fail and damage frequency-sensitive components. For this reason, silicone rubber modified by blending cannot be used under low temperature conditions.

[0004] Therefore, it is very important to develop a silicone rubber composition that can overcome the above-mentioned defects. Summary of the invention

[0005] In view of the above problems, the present application provides a silicone rubber composition and its application. The silicone rubber composition has excellent mechanical properties, cold resistance, oil resistance and damping properties, and can be applied to shock absorbers, especially suitable for shock absorbers working in low temperature and oily environments.

[0006] In a first aspect, the present application provides a silicone rubber composition, comprising silicone rubber and fluorosilane-modified fumed silica.

[0007] In the technical solution of the implementation mode of the present application, silicone rubber is modified by fluorosilane-modified fumed silica, wherein the fluorosilane-modified fumed silica as a whole, relative to the simple blending of fluorosilane and silicone rubber, the silicone rubber composition described in the present application has better oil resistance, and the modulus changes less at low temperatures than at low temperatures, and is less sensitive to temperature, and can be applied to shock absorbers in a wide temperature range; in addition, the fumed silica has a good reinforcing effect on the silicone rubber composition, so that the silicone rubber composition described in the present application has better mechanical properties and can be applied in relatively harsh environments.

[0008] In some embodiments, the silicone rubber composition comprises the following components in parts by weight:

[0009] Silicone rubber 100 parts

[0010] 30 to 80 parts of fluorosilane-modified fumed silica, optionally 40 to 80 parts.

[0011] In the technical solution of the implementation mode of the present application, the addition amount of fluorosilane-modified fumed silica within the above-mentioned range is more conducive to improving the performance of the silicone rubber composition; if its addition amount is too high, it will lead to difficulty in processing; if its addition amount is too low, it will lead to insufficient oil resistance and mechanical properties.

[0012] In some embodiments, the fluorosilane-modified fumed silica includes fumed silica and fluorosilane disposed on a surface of the fumed silica.

[0013] In the technical solution of the implementation mode of the present application, the fluorosilane-modified fumed silica has a coating structure, which can effectively improve the comprehensive performance of silicone rubber as a whole on the one hand, and has good compatibility with other components on the other hand, and the formed silicone rubber composition has stable performance.

[0014] In some embodiments, based on 100 parts by weight of the fumed silica, the weight of the fluorosilane is 1-10 parts.

[0015] In the technical solution of the implementation mode of the present application, the fumed silica and fluorosilane have the above-mentioned proportional relationship, and the fluorosilane-modified fumed silica formed has a more obvious improvement on the performance of silicone rubber. Specifically, if the addition amount of fluorosilane is too low, it will cause insufficient oil resistance; if the content of fluorosilane is too high, it will cause the precipitation of fluorosilane in the system and affect the mechanical strength.

[0016] In some embodiments, the particle size of the fumed silica is 7 to 500 nm, and optionally 200 to 500 nm.

[0017] In some embodiments, the specific surface area of ​​the fumed silica is 100 to 400 m2 / g.

[0018] In some embodiments, the structural formula of the fluorosilane is as shown in Formula I: R1R2R3-Si-R4-K;

[0019] wherein R1, R2 and R3 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy;

[0020] R4 is selected from a single bond, a substituted or unsubstituted C1-C30 alkylene group;

[0021] The substituent is selected from deuterium, halogen, hydroxyl, thiol, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, C1-C6 alkyl;

[0022] K is selected from trifluoropropyl or perfluorodecyl.

[0023] In some embodiments, the silicone rubber includes at least one —R5R6SiO— structural unit;

[0024] wherein R5 and R6 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C30 aryl;

[0025] The substituent is selected from deuterium, halogen, hydroxyl, mercapto, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, and C1-C6 alkyl.

[0026] In some embodiments, the viscosity average molecular weight of the silicone rubber is 10 3 ~10 6 g / mol, optional 10 5 ~10 6 g / mol.

[0027] In some embodiments, the silicone rubber composition further includes a vulcanizing agent.

[0028] In some embodiments, based on 100 parts by weight of the silicone rubber, the weight of the vulcanizing agent is 0.1-3 parts.

[0029] In some embodiments, the vulcanizing agent includes a compound containing a peroxide group.

[0030] In some embodiments, the vulcanizing agent includes any one of dicumyl peroxide, 2,4-di-tert-butyl dicumyl peroxide, 2,4-dichlorobenzoyl peroxide or 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, or a combination of at least two thereof.

[0031] In some embodiments, the silicone rubber composition further includes silicone oil.

[0032] In some embodiments, based on 100 parts by weight of the silicone rubber, the weight of the silicone oil is 0.1-5 parts.

[0033] In some embodiments, the silicone oil includes at least one —R7R8SiO— structural unit;

[0034] Wherein, R7 and R8 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C30 aryl;

[0035] The substituent is selected from deuterium, halogen, hydroxyl, mercapto, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, and C1-C6 alkyl.

[0036] In some embodiments, the viscosity average molecular weight of the silicone oil is ≤10000 g / mol.

[0037] In some embodiments, the silicone rubber composition includes an antioxidant.

[0038] In some embodiments, based on 100 parts by weight of the silicone rubber, the weight of the antioxidant is 0.1-2 parts.

[0039] In some embodiments, the antioxidant includes red iron.

[0040] In a second aspect, the present application provides a vibration damper, comprising the silicone rubber composition described in the first aspect.

[0041] Compared with the prior art, the technical solution described in this application has the following beneficial effects:

[0042] (1) The silicone rubber composition described in the present application has excellent mechanical properties, cold resistance, oil resistance and damping properties, and can be applied to shock absorbers, especially shock absorbers working in low temperature and oily environments.

[0043] (2) The tensile strength of the silicone rubber composition described in the present application is above 6.4 MPa, the loss tangent is between 0.12-0.21, the -60°C compression cold resistance coefficient is above 0.54, and the weight change rate after 24 hours of immersion in RP-3 fuel is within 173%; within the preferred range, the tensile strength of the silicone rubber composition described in the present application is above 8.1 MPa, the loss tangent is between 0.19-0.21, the -60°C compression cold resistance coefficient is above 0.58, and the weight change rate after 24 hours of immersion in RP-3 fuel is within 82%.

[0044] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0045] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the description and claims of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0047] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "2-10" means that all real numbers between "2-10" are listed in this document, and "2-10" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0050] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0051] In the prior art, silicone rubber has the defect that it is difficult to balance oil resistance, low temperature resistance and mechanical properties, and its application in shock absorbers is limited.

[0052] The present application solves the above technical problems by combining fluorosilane-modified fumed silica with silicone rubber to form a silicone rubber composition. The present application provides a silicone rubber composition and its application.

[0053] [Silicone rubber composition]

[0054] The present application provides a silicone rubber composition, which comprises silicone rubber and fluorosilane-modified fumed silica.

[0055] In the technical solution of the embodiment of the present application, silicone rubber is modified by fluorosilane-modified fumed silica, wherein the fluorosilane-modified fumed silica as a whole, relative to the simple blending of fluorosilane and silicone rubber, the silicone rubber composition described in the present application has better oil resistance, and the modulus changes less at low temperatures than at low temperatures, and is less sensitive to temperature, and can be applied to shock absorbers in a wide temperature range; in addition, the fumed silica has a good reinforcing effect on the silicone rubber composition, so that the silicone rubber composition described in the present application has better weather resistance, and can be applied in relatively harsh environments.

[0056] In some embodiments, the silicone rubber composition comprises the following components in parts by weight:

[0057] Silicone rubber 100 parts

[0058] The amount of fluorosilane-modified fumed silica is 30 to 80 parts, optionally 40 to 80 parts, and further optionally 50 to 80 parts.

[0059] In the present application, the weight proportion of the fluorosilane-modified fumed silica is 30 to 80 parts, for example, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, etc.

[0060] In the technical solution of the embodiment of the present application, the addition amount of fluorosilane-modified fumed silica within the above range is more conducive to improving the performance of the silicone rubber composition; if its addition amount is too high, it will lead to difficulty in processing; if its addition amount is too low, it will lead to insufficient oil resistance and mechanical properties.

[0061] In some embodiments, the fluorosilane-modified fumed silica includes fumed silica and fluorosilane disposed on a surface of the fumed silica.

[0062] In the present application, the fluorosilane-modified fumed silica can be a commercial product or homemade. For example, the preparation method of the fluorosilane-modified fumed silica includes the following steps:

[0063] The fumed silica and 3,3,3-trifluoropropyltrimethoxysilane are mixed in a high-speed heating mixer to obtain the fluorosilane-modified fumed silica.

[0064] In the technical solution of the embodiment of the present application, the fluorosilane-modified fumed silica has a coating structure, which can effectively improve the comprehensive performance of silicone rubber as a whole on the one hand, and has good compatibility with other components on the other hand, and the formed silicone rubber composition has stable performance.

[0065] In some embodiments, based on 100 parts by weight of the fumed silica, the weight of the fluorosilane is 1-10 parts, such as 2 parts, 4 parts, 6 parts, 8 parts, etc.

[0066] In the technical solution of the embodiment of the present application, the fumed silica and fluorosilane have the above-mentioned proportional relationship, and the fumed silica modified with fluorosilane has a more obvious improvement in the performance of silicone rubber. Specifically, if the amount of fluorosilane added is too low, it will cause insufficient oil resistance; if the content of fluorosilane is too high, it will cause fluorosilane to precipitate in the system and affect the mechanical strength.

[0067] In some embodiments, the particle size of the fumed silica is 7 to 500 nm (e.g., 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, etc.), and optionally 200 to 500 nm.

[0068] In some embodiments, the specific surface area of ​​the fumed silica is 100 to 400 m 2 / g, for example 150m 2 / g, 200m 2 / g, 250m 2 / g、300m 2 / g, 350m 2 / g, etc.

[0069] In some embodiments, the structural formula of the fluorosilane is as shown in Formula I: R1R2R3-Si-R4-K;

[0070] wherein R1, R2 and R3 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkyl, substituted or unsubstituted C2-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkenyl, substituted or unsubstituted C1-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkoxy, and are optionally halogen, methyl, methoxy or ethoxy;

[0071] R4 is selected from a single bond, substituted or unsubstituted C1-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkylene;

[0072] The substituent is selected from deuterium, halogen, hydroxyl, thiol, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, C1-C6 (e.g., C2, C3, C4, C5, etc.) alkyl;

[0073] K is selected from trifluoropropyl or perfluorodecyl.

[0074] In the present application, the C1-C30 alkyl group refers to an alkyl group having 1 to 30 carbon atoms in the main chain, and other similar expressions are the same.

[0075] When the aforementioned alkyl group contains an oxygen atom, it may be an alkoxy group.

[0076] Halogen includes fluorine, chlorine, bromine and iodine, optionally fluorine.

[0077] In the present application, the fluorosilane can be a commercial product or homemade. As an example, the fluorosilane specifically includes any one of 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane or perfluorohexyltrimethoxysilane, or a combination of at least two thereof.

[0078] In some embodiments, the silicone rubber includes at least one —R5R6SiO— structural unit;

[0079] wherein R5 and R6 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkyl, substituted or unsubstituted C2-C20 (e.g., C2, C5, C10, C15, etc.) alkenyl, substituted or unsubstituted C1-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkoxy, substituted or unsubstituted C6-C30 (e.g., C10, C15, C20, C25, etc.) aryl;

[0080] The substituent is selected from deuterium, halogen, hydroxyl, mercapto, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, C1-C6 (e.g., C2, C3, C4, C5, etc.) alkyl.

[0081] In the present application, the silicone rubber may be a linear structure, a chain structure containing side groups, a hyperbranched structure or a tree structure.

[0082] In some embodiments, the viscosity average molecular weight of the silicone rubber is 10 3 ~10 6 g / mol, for example 5×10 3 g / mol, 10 4 g / mol, 5×10 4 g / mol, 10 5 g / mol, 5×10 5 g / mol, etc., can be selected as 10 5 ~10 6 g / mol.

[0083] In the present application, the silicone rubber may be a commercial product or may be homemade. As an example, the silicone rubber specifically includes any one of methyl silicone rubber, ethyl silicone rubber or methyl phenyl silicone rubber, or a combination of at least two thereof.

[0084] In some embodiments, the silicone rubber composition further includes a vulcanizing agent.

[0085] In some embodiments, based on 100 parts by weight of the silicone rubber, the weight of the vulcanizing agent is 0.1-3 parts, such as 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, etc.

[0086] In some embodiments, the vulcanizing agent includes a compound containing a peroxide group.

[0087] In some embodiments, the vulcanizing agent includes any one of dicumyl peroxide, 2,4-di-tert-butyl dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, or 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, or a combination of at least two thereof.

[0088] In some embodiments, the silicone rubber composition further includes silicone oil.

[0089] In some embodiments, based on 100 parts by weight of the silicone rubber, the weight of the silicone oil is 0.1-5 parts, for example, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc.

[0090] In some embodiments, the silicone oil includes at least one —R7R8SiO— structural unit;

[0091] wherein R7 and R8 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkyl, substituted or unsubstituted C2-C20 (e.g., C2, C5, C10, C15, etc.) alkenyl, substituted or unsubstituted C1-C30 (e.g., C2, C5, C10, C15, C20, C25, etc.) alkoxy, substituted or unsubstituted C6-C30 aryl, and are optionally methyl, ethyl, vinyl, phenyl or trifluoropropyl;

[0092] The substituent is selected from deuterium, halogen, hydroxyl, mercapto, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, C1-C6 (e.g., C2, C3, C4, C5, etc.) alkyl.

[0093] In the present application, the silicone oil may be a linear structure, a chain structure containing side groups, a hyperbranched structure or a dendritic structure.

[0094] In some embodiments, the viscosity average molecular weight of the silicone oil is ≤10000 g / mol, for example 2000 g / mol, 4000 g / mol, 6000 g / mol, 8000 g / mol, etc., optionally 1000-10000 g / mol.

[0095] In the present application, the silicone oil can be a commercial product or homemade. As an example, the silicone oil specifically includes any one of hydroxy silicone oil, vinyl silicone oil or dimethyl silicone oil, or a combination of at least two of them.

[0096] In some embodiments, the silicone rubber composition includes an antioxidant.

[0097] In some embodiments, based on 100 parts by weight of the silicone rubber, the weight of the antioxidant is 0.1 to 2 parts, such as 0.2 parts, 0.5 parts, 1 part, 1.5 parts, etc., optionally 0.1 to 1 part.

[0098] In some embodiments, the antioxidant includes red iron oxide, which can also function as a dye.

[0099] As an example, the silicone rubber composition includes the following components in parts by weight:

[0100]

[0101]

[0102] [Application of silicone rubber composition]

[0103] The present application provides a vibration damper, which comprises the silicone rubber composition.

[0104] In the present application, the silicone rubber composition has excellent mechanical properties, cold resistance, oil resistance and damping properties, and can be applied to shock absorbers, especially shock absorbers working in low temperature and oily environments.

[0105] [Example]

[0106] Example 1

[0107] The components are mixed according to the following formula to obtain the silicone rubber composition:

[0108]

[0109] Among them, the specific information of each raw material is as follows:

[0110] Silicone rubber: methyl phenyl silicone rubber, viscosity average molecular weight is 8×10 5 g / mol, purchased from Shanghai Resin Factory, brand number 120-1.

[0111] Silicone oil: Hydroxy silicone oil, purchased from Guangzhou Fuze New Materials Co., Ltd., brand DL-30H.

[0112] Fluorosilane-modified fumed silica: Fluorosilane is coated on the surface of fumed silica, and the mass ratio of fumed silica to fluorosilane is 100:2; fluorosilane is 3,3,3-trifluoropropyltrimethoxysilane, purchased from Sysbo Organic Silicone; the particle size of fumed silica is basically distributed between 200 and 500 nm, and the specific surface area is distributed between 100 and 400 m 2 / g, purchased from Degussa, brand A-150.

[0113] The fluorosilane-modified fumed silica is obtained by the following preparation method: fumed silica and 3,3,3-trifluoropropyltrimethoxysilane are mixed in a high-speed heating mixer to obtain the fluorosilane-modified fumed silica.

[0114] Curing agent: 2,4-di-tert-butyl diisopropylbenzene peroxide.

[0115] Example 2

[0116] The components are mixed according to the following formula to obtain the silicone rubber composition:

[0117] Silicone rubber 100 parts

[0118] 80 parts of fluorosilane-modified fumed silica

[0119] 3 parts of vulcanizing agent.

[0120] Among them, the specific information of each raw material is as follows:

[0121] Silicone rubber: The structural formula is methyl ethyl silicone rubber, and the viscosity average molecular weight is 4×10 5 g / mol.

[0122] Fluorosilane-modified fumed silica: Fluorosilane is coated on the surface of fumed silica, and the mass ratio of fumed silica to fluorosilane is 100:8; the fluorosilane is perfluorodecyltrimethoxysilane, purchased from Sysbo Silicone, with the brand name PC9751; the particle size of fumed silica is basically distributed between 200 and 500 nm, and the specific surface area is distributed between 100 and 400 m 2 / g.

[0123] Curing agent: 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0124] Example 3

[0125] The difference between this embodiment and embodiment 1 is that in the fluorosilane-modified fumed silica, the mass ratio of fumed silica to fluorosilane is 100:12, and the rest is the same as embodiment 1.

[0126] Example 4

[0127] The difference between this embodiment and embodiment 1 is that in the fluorosilane-modified fumed silica, the mass ratio of fumed silica to fluorosilane is 100:0.5, and the rest is the same as embodiment 1.

[0128] Example 5

[0129] The difference between this embodiment and embodiment 1 is that the weight proportion of the fluorosilane-modified fumed silica is 90 parts, and the rest is the same as embodiment 1.

[0130] Example 6

[0131] The difference between this embodiment and embodiment 1 is that the weight proportion of the fluorosilane-modified fumed silica is 20 parts, and the rest is the same as embodiment 1.

[0132] Comparative Example 1

[0133] The difference between this comparative example and Example 1 is that the fumed silica is replaced with diatomaceous earth of equal mass to form diatomaceous earth modified with fluorosilane of equal mass, and the rest is the same as Example 1.

[0134] Comparative Example 2

[0135] The difference between this comparative example and Example 1 is that the fluorosilane-modified fumed silica is replaced with fumed silica of equal mass, and the rest is the same as Example 1.

[0136] Comparative Example 3

[0137] The difference between this comparative example and Example 1 is that the fluorosilane is not modified fumed silica, and the silicone rubber composition comprises the following components in parts by weight:

[0138]

[0139] The specific types of each raw material are the same as those in Example 1.

[0140] Comparative Example 4

[0141] The difference between this comparative example and Example 1 is that the fluorosilane-modified fumed silica is replaced by an equal mass of fumed silica, and the silicone rubber is replaced by an equal mass of fluorosilicone rubber, and the rest is the same as Example 1.

[0142] Specifically, the viscosity average molecular weight of the fluorosilicone rubber is 5×10 5g / mol, purchased from Fujian Yonghong High-tech Materials Co., Ltd. with the brand name G1001HR.

[0143] [Performance test]

[0144] After the components of the silicone rubber composition are uniformly mixed according to the formula, the following tests are performed:

[0145] (1) Tensile strength: Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber in accordance with GB / T 528.

[0146] (2) Damping performance (loss tangent): The test was conducted using dynamic thermomechanical analysis, wherein the test parameters were: tensile mode, 15% static strain, 5% dynamic strain, and a frequency of 30 Hz.

[0147] (3) Compression cold resistance: Determination of compression cold resistance coefficient of vulcanized rubber in accordance with HG / T 3866.

[0148] (4) Oil resistance: The silicone rubber composition was immersed in No. 3 jet fuel (RP-3 fuel) for 24 hours. The weight before and after immersion was weighed respectively. The weight change rate was calculated according to: (weight after immersion - weight before immersion) / weight before immersion.

[0149] The test results are summarized in Table 1.

[0150] Table 1

[0151]

[0152] In the table, “ / ” represents untested data.

[0153] Analysis of the data in Table 1 shows that the tensile strength of the silicone rubber composition described in the present application is above 6.4 MPa, the loss tangent is between 0.12-0.21, the -60°C compression cold resistance coefficient is above 0.54, and the weight change rate after 24 hours of RP-3 fuel immersion is within 173%; within a preferred range, the tensile strength of the silicone rubber composition described in the present application is above 8.1 MPa, the loss tangent is between 0.19-0.21, the -60°C compression cold resistance coefficient is above 0.58, and the weight change rate after 24 hours of RP-3 fuel immersion is within 82%; the silicone rubber composition described in the present application has excellent mechanical properties, cold resistance, oil resistance and damping properties, and can be used in shock absorbers, especially shock absorbers working in low temperature and oily environments.

[0154] Analysis of Comparative Examples 1-4 and Example 1 shows that the comprehensive performance of Comparative Examples 1-4 is not as good as that of Example 1. For example, the tensile strength of Comparative Example 1 is significantly lower, the oil resistance of Comparative Examples 2 and 3 is poor, and the cold resistance of Comparative Example 4 is poor, which proves that the silicone rubber composition described in the present application has better performance.

[0155] Analysis of Examples 3-4 and Example 1 shows that the performance of Examples 3-4 is not as good as that of Example 1, which proves that in the fluorosilane-modified fumed silica, the mass ratio of fluorosilane to fumed silica within the stated range is more conducive to improving the performance of the silicone rubber composition.

[0156] Analysis of Examples 5-6 and Example 1 shows that the performance of Examples 5-6 is not as good as that of Example 1, wherein the silicone rubber composition described in Example 5 has poor processability, proving that the addition amount of fluorosilane-modified fumed silica within the stated range is more conducive to improving the performance of the silicone rubber composition.

[0157] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A silicone rubber composition, characterized in that: The silicone rubber composition comprises silicone rubber and fluorosilane-modified fumed silica.

2. The silicone rubber composition according to claim 1, characterized in that The silicone rubber composition comprises the following components in parts by weight: Silicone rubber 100 parts 30 to 80 parts of fluorosilane-modified fumed silica, optionally 40 to 80 parts.

3. The silicone rubber composition according to claim 1 or 2, characterized in that: The fluorosilane-modified fumed silica comprises fumed silica and fluorosilane disposed on the surface of the fumed silica; Preferably, based on 100 parts by weight of the fumed silica, the weight of the fluorosilane is 1-10 parts.

4. The silicone rubber composition according to any one of claims 1 to 3, characterized in that: The particle size of the fumed silica is 7 to 500 nm, and optionally 200 to 500 nm; Preferably, the specific surface area of ​​the fumed silica is 100 to 400 m 2 / g.

5. The silicone rubber composition according to any one of claims 1 to 4, characterized in that: The structural formula of the fluorosilane is shown in Formula I: R1R2R3-Si-R4-K; wherein R1, R2 and R3 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy; R4 is selected from a single bond, a substituted or unsubstituted C1-C30 alkylene group; The substituent is selected from deuterium, halogen, hydroxyl, thiol, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, C1-C6 alkyl; K is selected from trifluoropropyl or perfluorodecyl.

6. The silicone rubber composition according to any one of claims 1 to 5, characterized in that: The silicone rubber comprises at least one —R5R6SiO— structural unit; wherein R5 and R6 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C30 aryl; The substituent is selected from deuterium, halogen, hydroxyl, thiol, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, C1-C6 alkyl; Preferably, the viscosity average molecular weight of the silicone rubber is 10 3 ~10 6 g / mol, optional 10 5 ~10 6 g / mol.

7. The silicone rubber composition according to any one of claims 1 to 6, characterized in that: The silicone rubber composition also includes a vulcanizing agent; Preferably, based on 100 parts by weight of the silicone rubber, the weight of the vulcanizing agent is 0.1-3 parts; Preferably, the vulcanizing agent comprises a compound containing a peroxide group; Preferably, the vulcanizing agent includes any one of dicumyl peroxide, 2,4-di-tert-butyl dicumyl peroxide, 2,4-dichlorobenzoyl peroxide or 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, or a combination of at least two thereof.

8. The silicone rubber composition according to any one of claims 1 to 7, characterized in that: The silicone rubber composition also includes silicone oil; Preferably, based on 100 parts by weight of the silicone rubber, the weight of the silicone oil is 0.1-5 parts. Preferably, the silicone oil comprises at least one —R7R8SiO— structural unit; Wherein, R7 and R8 are each independently selected from H, halogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C30 aryl; The substituent is selected from deuterium, halogen, hydroxyl, thiol, nitro, cyano, amino, carboxyl, sulfonyl, hydrazine, urea, C1-C6 alkyl; Preferably, the viscosity average molecular weight of the silicone oil is ≤10000 g / mol.

9. The silicone rubber composition according to any one of claims 1 to 8, characterized in that: The silicone rubber composition includes an antioxidant; Preferably, based on 100 parts by weight of the silicone rubber, the weight of the antioxidant is 0.1-2 parts; Preferably, the antioxidant includes red iron.

10. A shock absorber, characterized in that: The vibration damper comprises the silicone rubber composition according to any one of claims 1 to 9.

Images