Silicone rubber-based curable composition, blade member

Abstract

To provide a silicone rubber-based curable composition excellent in abrasion resistance.SOLUTION: The silicone rubber-based curable composition of the present invention is used for forming a blade member and contains a vinyl group-containing polyorganosiloxane (A) and silica particles (C) surface-treated with a silane coupling agent (D).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a silicone rubber-based curable composition and a blade part. Material Related thereto.

Background Art

[0002] Various developments have been made on sliding members such as wiper blades. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes a wiper blade made of silicone rubber (Claim 1 of Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as a result of the study by the present inventor, it has been found that there is room for improvement in terms of abrasion resistance in the wiper blade described in Patent Document 1 above.

Means for Solving the Problems

[0005] As a result of further study by the present inventor, it has been found that by including silica particles surface-treated with a silane coupling agent in the silicone rubber used for blade members such as wiper blades, the abrasion resistance of the cured product (silicone rubber) of the silicone rubber-based curable composition can be improved, and the present invention has been completed.

[0006] According to the present invention, [[ID=�9]] A silicone rubber-based curable composition used for forming a blade member, Vinyl group-containing polyorganosiloxane (A), Silica particles (C) surface-treated with a silane coupling agent (D), A silicone rubber-based curable composition containing the following is provided.

[0007] Furthermore, according to the present invention, A blade member comprising a cured product of the above-mentioned silicone rubber-based curable composition is provided.

[0008] Furthermore, according to the present invention, A wiper blade is provided that comprises a cured product of the above-mentioned silicone rubber-based curable composition. [Effects of the Invention]

[0009] According to the present invention, a silicone rubber-based curable composition with excellent wear resistance, a blade member using the same, and a wiper blade are provided. [Modes for carrying out the invention]

[0010] The silicone rubber-based curable composition of this embodiment will now be described.

[0011] The silicone rubber-based curable composition of this embodiment is used to form a part of the blade member. This silicone rubber-based curable composition comprises a vinyl group-containing polyorganosiloxane (A) and silica particles (C) surface-treated with a silane coupling agent (D).

[0012] According to the inventors' findings, it has been found that by using a vinyl group-containing polyorganosiloxane (A) and silica particles (C) surface-treated with a silane coupling agent (D), wear loss in the Taber abrasion test can be reduced, thereby improving wear resistance.

[0013] Although the detailed mechanism is not clear, it is believed that by appropriately selecting the components of a silicone rubber-based curable composition, the tear strength and elongation at break, which are rubber properties of silicone rubber, can be appropriately controlled, thereby reducing wear loss in the Taber abrasion test.

[0014] The silicone rubber-based curable composition of this embodiment exhibits excellent wear resistance, enabling the creation of a silicone rubber suitable for blade components such as wiper blades and general sliding components.

[0015] The blade member and wiper blade of this embodiment include a cured product of a silicone rubber-based curable composition.

[0016] In this embodiment, the blade member can be used as a component of vehicles, electronic equipment, machine tools, and buildings, and examples include wiper blades used in vehicles such as automobiles and trains, ships, and aircraft.

[0017] The following describes the details of the silicone rubber-based curable composition.

[0018] The tear strength of the cured product of the silicone rubber-based curable composition, measured according to the following procedure, is defined as TS (N / mm) and the elongation at break as BE (%).

[0019] (Procedure for measuring tear strength) Using a cured silicone rubber-based curable composition, crescent-shaped test specimens are prepared in accordance with JIS K6252 (2001), and the tear strength of the obtained crescent-shaped test specimens is measured at 25°C. The unit is N / mm.

[0020] (Procedure for measuring elongation at break) Using a cured silicone rubber-based curable composition, a dumbbell-shaped No. 3 test specimen was prepared in accordance with JIS K6251 (2004), and the elongation at break of the obtained dumbbell-shaped No. 3 test specimen was measured at 25°C. The elongation at break was calculated as [gauge displacement (mm)] ÷ [initial gauge distance (20 mm)] × 100. The unit is %.

[0021] The silicone rubber-based curable composition of this embodiment has TS and BE of 2.3 × 10 4 It may be configured such that ≤TS × BE is satisfied.

[0022] The lower limit of TS×BE is 2.3×10 4 Preferably 2.4 × 10 4 More preferably 2.8 × 10 4 This concludes the explanation. This makes it possible to create a silicone rubber with excellent abrasion resistance. On the other hand, the upper limit of TS×BE is not particularly limited, but for example, 5.0×10 5 The following is also acceptable: 1.0 × 10 5 The following is also acceptable: 9.0 × 10 4 The following is also acceptable. This results in a silicone rubber with an excellent balance of properties.

[0023] According to the inventors' findings, the abrasion resistance of silicone rubber can be reliably evaluated by using the cumulative value of tear strength and elongation at break as an indicator, and it has been found that by setting this cumulative value above the above lower limit, the wear loss due to Taber abrasion testing can be reduced.

[0024] Although the detailed mechanism is not clear, it is thought that by increasing the cumulative value of tear strength and elongation at break, the wear resistance is improved, making it less likely to break due to friction with other materials.

[0025] The lower limit of the tear strength is, for example, 25 N / mm or more, preferably 28 N / mm or more, more preferably 30 N / mm or more, even more preferably 33 N / mm or more, and even more preferably 35 N / mm or more. This improves the durability of the silicone rubber during repeated use. It also improves the scratch resistance and mechanical strength of the silicone rubber. On the other hand, the upper limit of the tear strength is not particularly limited, but may be, for example, 80 N / mm or less, or 70 N / mm or less. This allows for a balance of the various properties of the silicone rubber.

[0026] The durometer hardness A of the cured product of a silicone rubber-based curable composition is measured by the following procedure. The upper limit of the durometer hardness A is not particularly limited, but for example, it may be 90 or less, preferably 85 or less, and more preferably 80 or less. This allows for a balance in the cured properties of the silicone rubber. This allows for adjustment of the deformability of the silicone rubber, such as ease of bending and stretching. On the other hand, the lower limit of the durometer hardness A is not particularly limited, but for example, it is 30 or higher, preferably 33 or higher, and more preferably 35 or higher. This increases the mechanical strength of the silicone rubber.

[0027] (Measurement procedure for durometer hardness A) A sheet-like test specimen is prepared using the cured product of the silicone rubber-based curable composition, and the durometer hardness A of the obtained sheet-like test specimen is measured at 25°C in accordance with JIS K6253 (1997).

[0028] In this embodiment, the hardness, elongation at break, and tear strength can be controlled by appropriately selecting, for example, the type and amount of each component contained in the silicone rubber curable composition, the method of preparing the silicone rubber curable composition, etc. Among these, for example, appropriately controlling the type and blending ratio of the resin constituting the silicone rubber, the crosslinking density and crosslinking structure of the resin, the blending ratio of the inorganic filler, and improving the dispersibility of the inorganic filler with a silane coupling agent are examples of factors that can bring the hardness, elongation at break, and tear strength into a desired numerical range.

[0029] Next, we will describe the compositional components of the silicone rubber-based curable composition.

[0030] The silicone rubber-based curable composition of this embodiment may contain a vinyl group-containing organopolysiloxane (A). The vinyl group-containing organopolysiloxane (A) is a polymer that forms the main component of the silicone rubber-based curable composition.

[0031] The vinyl group-containing organopolysiloxane (A) may include a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0032] The above vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, which serve as crosslinking points during curing.

[0033] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but it is preferable that it has two or more vinyl groups in the molecule and that the content is 15 mol% or less. This optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) and ensures the formation of a network with the components described later. In this specification, "~" indicates that the upper and lower limits are included unless otherwise specified.

[0034] In this specification, the vinyl group content refers to the mole percent of vinyl group-containing siloxane units when the total number of units constituting the vinyl group-containing linear organopolysiloxane (A1) is considered to be 100 mol%. However, it is assumed that there is one vinyl group per vinyl group-containing siloxane unit.

[0035] Furthermore, the degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of 1000 to 10000, and more preferably in the range of 2000 to 5000. The degree of polymerization can be determined, for example, by the number-average degree of polymerization (or number-average molecular weight) in terms of polystyrene in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0036] Furthermore, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of 0.9 to 1.1.

[0037] By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and a specific gravity within the above ranges, it is possible to improve the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber.

[0038] As the vinyl group-containing linear organopolysiloxane (A1), those having a structure represented by the following formula (1) are particularly preferred.

[0039] [Chemical formula]

[0040] In formula (1), R 1 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among them, a methyl group is preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group, etc., and among them, a vinyl group is preferred. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group, etc.

[0041] Also, R 2 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among them, a methyl group is preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0042] Also, R 3This group is a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group.

[0043] Furthermore, R in equation (1) 1 and R 2 Examples of substituents include methyl groups and vinyl groups, and R 3 Examples of substituents include methyl groups.

[0044] Note that in equation (1), multiple R 1 These are independent of each other, and may be different from each other or the same. Furthermore, R 2 , and R 3 The same applies to this matter.

[0045] Furthermore, m and n are the number of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1), where m is an integer from 0 to 2000 and n is an integer from 1000 to 10000. Preferably, m is from 0 to 1000 and n is from 2000 to 5000.

[0046] Furthermore, a specific structure of the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1) is, for example, the one represented by the following formula (1-1).

[0047] [ka]

[0048] In formula (1-1), R 1 and R 2 Each of these is independently either a methyl group or a vinyl group, and at least one of them is a vinyl group.

[0049] The vinyl group-containing linear organopolysiloxane (A1) may include a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and containing 0.4 mol% or less. The amount of vinyl groups in the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

[0050] Furthermore, the vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol%.

[0051] By combining a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) with a high vinyl group content, the vinyl groups can be unevenly distributed, allowing for more effective formation of crosslink density variations within the crosslinking network of the silicone rubber. As a result, the tear strength of the silicone rubber can be more effectively increased.

[0052] Specifically, as a vinyl group-containing linear organopolysiloxane (A1), for example, in the above formula (1-1), R 1 The unit and / or R is a vinyl group. 2 A first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in the molecule that are vinyl groups and containing 0.4 mol% or less of them, and R 1 The unit and / or R is a vinyl group. 2 It is preferable to use a second vinyl group-containing linear organopolysiloxane (A1-2) containing 0.5 to 15 mol% of units in which the first unit is a vinyl group.

[0053] Furthermore, the first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol%. Also, the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol%.

[0054] Furthermore, when a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) are combined, the ratio of (A1-1) to (A1-2) is not particularly limited, but for example, a weight ratio of (A1-1):(A1-2) of 50:50 to 95:5 is preferred, and a weight ratio of 80:20 to 90:10 is more preferred.

[0055] Furthermore, the first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may be used individually or in combination of two or more types.

[0056] Furthermore, the vinyl group-containing organopolysiloxane (A) may also include a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0057] <<Organohydrogenpolysiloxane (B)>> The silicone rubber-based curable composition of this embodiment may contain organohydrogenpolysiloxane (B). Organohydrogenpolysiloxanes (B) are classified into linear organohydrogenpolysiloxanes (B1) having a linear structure and branched organohydrogenpolysiloxanes (B2) having a branched structure, and may include either one or both of these.

[0058] Linear organohydrogenpolysiloxane (B1) is a polymer having a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H), and undergoes a hydrosilylation reaction with vinyl groups of vinyl group-containing organopolysiloxane (A), as well as vinyl groups of components blended into silicone rubber-based curable compositions, thereby crosslinking these components.

[0059] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, it is preferable that the weight-average molecular weight is 20,000 or less, and more preferably 1,000 or more and 10,000 or less.

[0060] The weight-average molecular weight of linear organohydrogenpolysiloxane (B1) can be measured, for example, by converting it to polystyrene equivalent in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0061] Furthermore, it is preferable that the linear organohydrogenpolysiloxane (B1) does not typically have vinyl groups. This effectively prevents the crosslinking reaction from proceeding within the linear organohydrogenpolysiloxane (B1) molecule.

[0062] As the linear organohydrogenpolysiloxane (B1) described above, one having the structure represented by the following formula (2) is preferably used.

[0063] [ka]

[0064] In formula (2), R 4The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group formed by combining these groups, or a hydride group, all having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0065] Also, R 5 The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, hydrocarbon group, or hydride group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0066] Note that in equation (2), multiple R 4 These are independent of each other, and may be different from each other or the same. 5 The same applies to multiple Rs. 4 and R 5 Of these, at least two are hydride groups.

[0067] Also, R 6 R is a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group. Multiple R 6 These are independent of each other, and may be different from each other or the same.

[0068] Note that R in equation (2) 4 ,R 5 ,R 6Examples of substituents include methyl groups and vinyl groups, and methyl groups are preferred from the viewpoint of preventing intramolecular crosslinking reactions.

[0069] Furthermore, m and n are the number of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), where m is an integer from 2 to 150 and n is an integer from 2 to 150. Preferably, m is an integer from 2 to 100 and n is an integer from 2 to 100.

[0070] Furthermore, linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more types.

[0071] The branched organohydrogenpolysiloxane (B2) has a branched structure, which allows it to form regions with high crosslink density, and it is a component that greatly contributes to the formation of a dense-sparse crosslink structure in the silicone rubber system. Also, similar to the linear organohydrogenpolysiloxane (B1) described above, it has a structure in which hydrogen is directly bonded to Si (≡Si-H), and it is a polymer that undergoes hydrosilylation reactions with the vinyl groups of vinyl group-containing organopolysiloxane (A) as well as the vinyl groups of components blended into the silicone rubber curable composition, thereby crosslinking these components.

[0072] Furthermore, the specific gravity of branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0073] Furthermore, it is preferable that the branched organohydrogenpolysiloxane (B2) does not typically have vinyl groups. This effectively prevents the crosslinking reaction from proceeding within the branched organohydrogenpolysiloxane (B2) molecule.

[0074] Furthermore, the branched organohydrogenpolysiloxane (B2) is preferably the one shown in the following average composition formula (c).

[0075] Average composition formula (c) (H a (R7 ) 3-a SiO 1 / 2 ) m (SiO 4 / 2 ) n (In equation (c), R 7 H is a monovalent organic group, a is an integer in the range of 1 to 3, and m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n is SiO 4 / 2 (The number of units)

[0076] In equation (c), R 7 The group is a monovalent organic group, preferably a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0077] In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si), and is an integer in the range of 1 to 3, preferably 1.

[0078] Also, in equation (c), m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n is SiO 4 / 2 It is the number of units.

[0079] Branched organohydrogenpolysiloxane (B2) has a branched structure. Linear organohydrogenpolysiloxane (B1) and branched organohydrogenpolysiloxane (B2) differ in their structure, with the number of alkyl groups R attached to Si (R / Si) being 1 when the number of Si is taken as 1. For linear organohydrogenpolysiloxane (B1), the range is 1.8 to 2.1, while for branched organohydrogenpolysiloxane (B2), it is 0.8 to 1.7.

[0080] Furthermore, because branched organohydrogenpolysiloxane (B2) has a branched structure, the amount of residue when heated to 1000°C at a heating rate of 10°C / min under a nitrogen atmosphere is 5% or more. In contrast, because linear organohydrogenpolysiloxane (B1) is linear, the amount of residue after heating under the above conditions is almost zero.

[0081] Furthermore, a specific example of a branched organohydrogenpolysiloxane (B2) is one having a structure represented by the following formula (3).

[0082] [ka]

[0083] In formula (3), R 7 R is a substituted or unsubstituted alkyl group, aryl group, or a hydrocarbon group combining these, or a hydrogen atom, having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group. 7 Examples of substituents include methyl groups.

[0084] Note that in equation (3), multiple R 7 These are independent of each other, and may be different from each other or the same.

[0085] Furthermore, in equation (3), "-O-Si≡" indicates that Si has a branched structure that extends in three dimensions.

[0086] Furthermore, branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more types.

[0087] Furthermore, the amount of hydrogen atoms (hydride groups) directly bonded to Si in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is not particularly limited. However, in the silicone rubber-based curable composition, it is preferable that the total amount of hydride groups in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is 0.5 to 5 moles, and more preferably 1 to 3.5 moles, per mole of vinyl groups in the vinyl group-containing linear organohydrogenpolysiloxane (A1). This ensures the reliable formation of a crosslinking network between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organohydrogenpolysiloxane (A1).

[0088] <<Silica particles (C)>> The silicone rubber-based curable composition of this embodiment may also contain silica particles (C) in addition to the vinyl group-containing polyorganosiloxane (A).

[0089] The silica particles (C) are not particularly limited, but for example, fumed silica, calcined silica, precipitated silica, etc., can be used. These may be used individually or in combination of two or more types.

[0090] Silica particles (C) have a specific surface area of, for example, 50-400 m² as determined by the BET method. 2 It is preferable that the amount is / g, and 100-400m 2 It is more preferable that the amount is / g. Furthermore, the average primary particle size of the silica particles (C) is preferably, for example, 1 to 100 nm, and more preferably about 5 to 20 nm.

[0091] By using silica particles (C) that fall within the specified range of specific surface area and average particle size, the hardness and mechanical strength of the resulting silicone rubber can be improved, particularly its tensile strength.

[0092] <<Silane coupling agent (D)>> The silicone rubber-based curable composition of this embodiment may contain a silane coupling agent (D). The silane coupling agent (D) may have a hydrolyzable group. The hydrolyzable group is hydrolyzed by water to a hydroxyl group, and this hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl groups on the surface of the silica particles (C), thereby modifying the surface of the silica particles (C).

[0093] Furthermore, this silane coupling agent (D) may include a silane coupling agent having hydrophobic groups. As a result, these hydrophobic groups are imparted to the surface of the silica particles (C), which is expected to reduce the cohesive force of the silica particles (C) in the silicone rubber curable composition and, consequently, in the silicone rubber itself (reduced aggregation due to hydrogen bonding by silanol groups). This is expected to improve the dispersibility of the silica particles in the silicone rubber curable composition. This increases the interface between the silica particles and the rubber matrix, thereby increasing the reinforcing effect of the silica particles. Moreover, it is expected that the slipperiness of the silica particles within the matrix improves during deformation of the rubber matrix. As a result of the improved dispersibility and slipperiness of the silica particles (C), the mechanical strength of the silicone rubber due to the silica particles (C) (e.g., tensile strength and tear strength) is improved.

[0094] Furthermore, the silane coupling agent (D) may include a silane coupling agent having vinyl groups. This introduces vinyl groups to the surface of the silica particles (C). Therefore, during the curing of the silicone rubber-based curable composition, that is, when the vinyl groups of the vinyl group-containing organopolysiloxane (A) and the hydride groups of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction to form a network (crosslinked structure), the vinyl groups of the silica particles (C) also participate in the hydrosilylation reaction with the hydride groups of the organohydrogenpolysiloxane (B), thus incorporating the silica particles (C) into the network. This makes it possible to achieve lower hardness and higher modulus in the formed silicone rubber.

[0095] As the silane coupling agent (D), a silane coupling agent having a hydrophobic group and a silane coupling agent having a vinyl group can be used in combination.

[0096] Examples of silane coupling agents (D) include those represented by the following formula (4).

[0097] Y n -Si-(X) 4-n ...(4) In formula (4) above, n represents an integer from 1 to 3. Y represents a functional group that has a hydrophobic group, a hydrophilic group, or a vinyl group, and when n is 1, it is a hydrophobic group, and when n is 2 or 3, at least one of them is a hydrophobic group. X represents a hydrolyzable group.

[0098] Hydrophobic groups are alkyl groups, aryl groups, or hydrocarbon groups having 1 to 6 carbon atoms, such as methyl groups, ethyl groups, propyl groups, and phenyl groups, with methyl groups being particularly preferred.

[0099] Furthermore, hydrophilic groups include, for example, hydroxyl groups, sulfonic acid groups, carboxyl groups, or carbonyl groups, with hydroxyl groups being particularly preferred. While hydrophilic groups may be included as functional groups, it is preferable that they are not included from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

[0100] Furthermore, hydrolyzable groups include alkoxy groups such as methoxy groups and ethoxy groups, chloro groups, or silazane groups, and among these, silazane groups are preferred due to their high reactivity with silica particles (C). Note that those having a silazane group as a hydrolyzable group are, due to their structural characteristics, (Y in formula (4) above. n It will have two -Si-) structures.

[0101] Specific examples of the silane coupling agent (D) represented by formula (4) above include, for example, alkoxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane, which have a hydrophobic group as a functional group; chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; and hexamethyldisilazane, which have a hydrophobic group as a functional group. Examples of materials having a vinyl group include alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane and vinylmethyldichlorosilane; and divinyltetramethyldisilazane. Among these, considering the above description, hexamethyldisilazane is particularly preferred as the material having a hydrophobic group, and divinyltetramethyldisilazane is preferred as the material having a vinyl group.

[0102] <<Platinum or platinum compound (E)>> The silicone rubber-based curable composition of this embodiment may contain platinum or a platinum compound (E). Platinum or platinum compound (E) is a catalytic component that acts as a catalyst during hardening. The amount of platinum or platinum compound (E) added is the catalytic amount.

[0103] As platinum or a platinum compound (E), known substances can be used, such as platinum black, platinum supported on silica or carbon black, chloroplatinic acid or an alcoholic solution of chloroplatinic acid, a complex salt of chloroplatinic acid and an olefin, or a complex salt of chloroplatinic acid and a vinylsiloxane.

[0104] Platinum or platinum compound (E) may be used alone or in combination of two or more types.

[0105] <<Water(F)>> Furthermore, the silicone rubber-based curable composition of this embodiment may also contain water (F) in addition to the above components (A) to (E).

[0106] Water (F) functions as a dispersion medium that disperses the various components contained in the silicone rubber curable composition, and also contributes to the reaction between silica particles (C) and the silane coupling agent (D). Therefore, the silica particles (C) and the silane coupling agent (D) can be more reliably linked to each other in the silicone rubber, resulting in uniform properties overall.

[0107] Furthermore, the silicone rubber-based curable composition of this embodiment may contain known additive components that are incorporated into silicone rubber-based curable compositions, in addition to the components (A) to (F) described above. Examples include diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, mica, etc. Other dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, thermal conductivity enhancers, etc., can be appropriately added.

[0108] In a silicone rubber-based curable composition, the proportion of each component is not particularly limited, but for example, it can be set as follows.

[0109] In this embodiment, the upper limit of the silica particle (C) content may be, for example, 80 parts by weight or less, preferably 75 parts by weight or less, and more preferably 70 parts by weight or less, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). This allows for a balance of mechanical strengths such as hardness and tensile strength. The lower limit of the silica particle (C) content is, for example, 20 parts by weight or more, preferably 25 parts by weight or more, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). This allows for a balance of tear strength and elongation at break.

[0110] The silane coupling agent (D) is preferably present in an amount of 5 to 100 parts by weight, and more preferably 5 to 40 parts by weight, per 100 parts by weight of the vinyl group-containing organopolysiloxane (A). This ensures that the dispersibility of silica particles (C) in the silicone rubber-based curable composition is reliably improved.

[0111] The content of organohydrogenpolysiloxane (B) is preferably, for example, 0.5 parts by weight or more and 20 parts by weight or less, and more preferably 0.8 parts by weight or more and 15 parts by weight or less, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D). A content of (B) within the above range may enable a more effective curing reaction.

[0112] The content of platinum or platinum compound (E) represents the catalytic amount and can be set as appropriate, but specifically, it is the amount such that the platinum group metal in this component is 0.01 to 1000 ppm by weight relative to the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D), preferably 0.1 to 500 ppm. By setting the content of platinum or platinum compound (E) to above the lower limit, the resulting silicone rubber composition can be sufficiently cured. By setting the content of platinum or platinum compound (E) to below the upper limit, the curing speed of the resulting silicone rubber composition can be improved.

[0113] Furthermore, if water (F) is included, its content can be set as appropriate, but specifically, it is preferably in the range of 10 to 100 parts by weight, and more preferably in the range of 30 to 70 parts by weight, per 100 parts by weight of the silane coupling agent (D). This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0114] <Method for manufacturing silicone rubber> Next, the method for manufacturing the silicone rubber of this embodiment will be described. The method for producing silicone rubber according to this embodiment involves preparing a silicone rubber-based curable composition and curing this silicone rubber-based curable composition to obtain silicone rubber. The details are explained below.

[0115] First, the components of the silicone rubber curable composition are uniformly mixed using any kneading device to prepare the silicone rubber curable composition.

[0116] [1] For example, a predetermined amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) are weighed out, and then kneaded using any kneading device to obtain a kneaded product containing these components (A), (C), and (D).

[0117] It is preferable to obtain this compound by first kneading a vinyl group-containing organopolysiloxane (A) and a silane coupling agent (D), and then kneading (mixing) silica particles (C). This further improves the dispersibility of silica particles (C) in the vinyl group-containing organopolysiloxane (A).

[0118] Furthermore, when obtaining this mixture, water (F) may be added to the mixture of components (A), (C), and (D) as needed. This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0119] Furthermore, it is preferable that the kneading of each component (A), (C), and (D) proceeds through a first step of heating at a first temperature and a second step of heating at a second temperature. This allows the surface of the silica particles (C) to be surface-treated with the coupling agent (D) in the first step, and ensures that by-products generated by the reaction between the silica particles (C) and the coupling agent (D) are reliably removed from the kneaded mixture in the second step. Subsequently, if necessary, component (A) may be added to the resulting kneaded mixture and kneaded further. This improves the compatibility of the components in the kneaded mixture.

[0120] The first temperature is preferably, for example, around 40 to 120°C, and more preferably, around 60 to 90°C. The second temperature is preferably, for example, around 130 to 210°C, and more preferably, around 160 to 180°C.

[0121] Furthermore, the atmosphere in the first step is preferably an inert atmosphere such as a nitrogen atmosphere, and the atmosphere in the second step is preferably a reduced pressure atmosphere.

[0122] Furthermore, the duration of the first step is preferably about 0.3 to 1.5 hours, and more preferably about 0.5 to 1.2 hours. The duration of the second step is preferably about 0.7 to 3.0 hours, and more preferably about 1.0 to 2.0 hours.

[0123] By setting the conditions for the first and second steps as described above, the aforementioned effects can be obtained more significantly.

[0124] [2] Next, predetermined amounts of organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) are weighed out, and then, using any kneading apparatus, components (B) and (E) are kneaded into the mixture prepared in step [1] above to obtain a silicone rubber curable composition. The obtained silicone rubber curable composition may be a paste containing a solvent.

[0125] Furthermore, when kneading each of these components (B) and (E), it is preferable to first knead the kneaded product prepared in step [1] with the organohydrogenpolysiloxane (B), and the kneaded product prepared in step [1] with platinum or a platinum compound (E), and then knead each of these kneaded products. This ensures that each of the components (A) to (E) can be reliably dispersed in the silicone rubber-based curable composition without allowing the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) to proceed.

[0126] The temperature at which components (B) and (E) are kneaded is preferably, as the roll setting temperature, around 10 to 70°C, and more preferably around 25 to 30°C.

[0127] Furthermore, the mixing time is preferably, for example, 5 minutes to 1 hour, and more preferably 10 to 40 minutes.

[0128] In steps [1] and [2] described above, by keeping the temperature within the above range, the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more effectively prevented or suppressed. Furthermore, in steps [1] and [2] described above, by keeping the kneading time within the above range, each component (A) to (E) can be more reliably dispersed in the silicone rubber-based curable composition.

[0129] The kneading equipment used in each of the processes [1] and [2] is not particularly limited, but for example, a kneader, a two-roll mixer, a Banbury mixer (continuous kneader), a pressure kneader, etc., can be used.

[0130] Furthermore, in step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded mixture. This makes it possible to more effectively prevent or suppress the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B), even if the temperature of the kneaded mixture is set to a relatively high temperature.

[0131] [3] Next, silicone rubber is formed by curing the silicone rubber-based curable composition.

[0132] In this embodiment, the curing process of the silicone rubber-based curable composition is carried out, for example, by heating at 100 to 250°C for 1 to 30 minutes (primary curing), followed by post-baking at 200°C for 1 to 4 hours (secondary curing). By following the steps described above, silicone rubber can be obtained using the silicone rubber-based curable composition of this embodiment.

[0133] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., within the scope that can achieve the objectives of the present invention are included in the present invention. Examples of reference formats are provided below. 1. A silicone rubber-based curable composition used to form a blade member, A vinyl group-containing polyorganosiloxane (A), Silica particles (C) surface-treated with a silane coupling agent (D), A silicone rubber-based curable composition containing the above. 2. The silicone rubber-based curable composition described in 1. A silicone rubber-based curable composition in which the silica particles (C) are contained in an amount of 20 to 80 parts by weight per 100 parts by weight of the vinyl group-containing polyorganosiloxane (A). 3. A silicone rubber-based curable composition as described in 1. or 2., When the tear strength is TS (N / mm) and the elongation at break is BE (%), When the tear strength of the cured product of the silicone rubber-based curable composition, measured according to the following procedure, is denoted as TS (N / mm) and the elongation at break as BE (%), TS, BE, 2.3 × 10 4 A silicone rubber-based curable composition satisfying ≤TS×BE. (Procedure for measuring tear strength) Using the cured product of the silicone rubber-based curable composition, crescent-shaped test specimens are prepared in accordance with JIS K6252 (2001), and the tear strength of the obtained crescent-shaped test specimens is measured at 25°C. The unit is N / mm. (Procedure for measuring elongation at break) Using the cured product of the silicone rubber-based curable composition, a dumbbell-shaped No. 3 test specimen was prepared in accordance with JIS K6251 (2004), and the elongation at break of the obtained dumbbell-shaped No. 3 test specimen was measured at 25°C. The elongation at break was calculated as [gauge displacement (mm)] ÷ [initial gauge distance (20 mm)] × 100. The unit is %. 4.3. A silicone rubber-based curable composition as described above, A silicone rubber-based curable composition having a tear strength of 25 N / mm or more. 5. A silicone rubber-based curable composition described in any one of 1. to 4., A silicone rubber-based curable composition having a durometer hardness A of 30 or more and 90 or less, as measured by the following procedure. (Measurement procedure for durometer hardness A) A sheet-like test specimen is prepared using the cured product of the silicone rubber-based curable composition, and the durometer hardness A of the obtained sheet-like test specimen is measured at 25°C in accordance with JIS K6253 (1997). 6. A silicone rubber-based curable composition described in any one of 1. to 5., A silicone rubber-based curable composition comprising a first vinyl group-containing linear organopolysiloxane (A1-1) in which the vinyl group-containing polyorganosiloxane (A) has two vinyl groups only at its terminal ends within the molecule and the amount of vinyl groups is 0.4 mol% or less. 7. A silicone rubber-based curable composition described in any one of 1. to 6., A silicone rubber-based curable composition comprising silica particles (C) surface-treated with a silane coupling agent having vinyl groups. 8. A blade member comprising a cured product of a silicone rubber-based curable composition described in any one of items 1 to 7. 9. A wiper blade comprising a cured product of a silicone rubber-based curable composition described in any one of items 1 to 7. [Examples]

[0134] The present invention will be described in detail below with reference to examples, but the present invention is not limited in any way to the descriptions of these examples.

[0135] The raw material components used in the examples and comparative examples shown in Table 1 are as follows. (Vinyl group-containing organopolysiloxane (A)) • Low vinyl group-containing linear organopolysiloxane (A1-1): A vinyl group-containing dimethylpolysiloxane synthesized by synthesis scheme 1 (with a structure represented by formula (1-1) and R 1 (A structure in which only the terminal is a vinyl group) • High vinyl group-containing linear organopolysiloxane (A1-2): A vinyl group-containing dimethylpolysiloxane synthesized by synthesis scheme 2 (with a structure represented by formula (1-1) and R 1 and R 2 (A structure in which the vinyl group is) • Low vinyl group-containing linear organopolysiloxane (A1-3): A vinyl group-containing dimethylpolysiloxane synthesized by synthesis scheme 3 (with a structure represented by formula (1-1) and R 1 and R 2 (A structure in which the vinyl group is)

[0136] (Organohydrogenpolysiloxane (B)) • Momentive Corporation: "TC-25D"

[0137] (Silica particles (C)) • Silica particles (C-1): Silica microparticles (particle size 7 nm, specific surface area 300 m²) 2 / g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL300" • Silica particles (C-2): Silica microparticles (particle size 7 nm, specific surface area 240 m²) 2 / g) "AEROSIL R976" manufactured by Nippon Aerosil Co., Ltd.

[0138] (Silane coupling agent (D)) • Silane coupling agent (D-1): Hexamethyldisilazane (HMDZ), manufactured by Gelest, "HEXAMETHYLDISILAZANE (SIH6110.1)" • Silane coupling agent (D-2): Divinyltetramethyldisilazane, manufactured by Gelest, "1,3-DIVINYLTETRAMETHYLDISILAZANE(SID4612.0)"

[0139] (Platinum or platinum compound (E)) • Momentive Corporation: "TC-25A"

[0140] (Synthesis of vinyl group-containing organopolysiloxane (A)) [Synthesis Scheme 1: Synthesis of a low-vinyl group-containing linear organopolysiloxane (A1-1)] A low-vinyl group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (5). Specifically, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium silicate were placed in a 300 mL separable flask equipped with a condenser and stirring blades, which had been purged with Ar gas. The mixture was then heated and stirred at 120°C for 30 minutes. An increase in viscosity was observed during this process. The temperature was then raised to 155°C, and stirring was continued for 3 hours. After 3 hours, 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added, and stirring was continued at 155°C for another 4 hours. Furthermore, after 4 hours, the mixture was diluted with 250 mL of toluene and washed three times with water. The organic layer after washing was reprecipitated and purified by washing several times with 1.5 L of methanol to separate the oligomer and polymer. The obtained polymer was dried under reduced pressure at 60°C overnight to obtain a low vinyl group-containing linear organopolysiloxane (A1-1) (Mn = 2.2 × 10⁻⁶). 5 Mw = 4.8 × 10 5 Furthermore, the vinyl group content, calculated by 1H-NMR spectroscopy, was 0.04 mol%.

[0141] [ka]

[0142] [Synthesis Scheme 2: Synthesis of high vinyl group-containing linear organopolysiloxanes (A1-2)] In the synthesis step of (A1-1) described above, 0.86 g (2.5 mmol) of 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane was used in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane. Except for this difference, the synthesis step was carried out in the same manner as in (A1-1), and a linear organopolysiloxane with a high vinyl group content (A1-2) was synthesized as shown in formula (6) below. (Mn = 2.3 × 10⁻¹⁰ 5 Mw = 5.0 × 10 5 Furthermore, the vinyl group content, calculated by 1H-NMR spectroscopy, was 0.93 mol%. [ka]

[0143] [Synthesis Scheme 3: Synthesis of Low-Vinyl Group-Containing Linear Organopolysiloxanes (A1-3)] In the synthesis step of (A1-2) described above, 75.3 g (254 mmol) of octamethylcyclotetrasiloxane and 0.12 g (0.35 mmol) of 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane were used, and the stirring time after raising the temperature to 155°C was 3 hours. Except for these differences, the synthesis step was carried out in the same manner as in (A1-2), thereby synthesizing the low-vinyl group-containing linear organopolysiloxane (A1-3) as shown in formula (6) above. (Mn = 2.5 × 10⁻⁶) 5 Mw = 5.0 × 10 5 Furthermore, the vinyl group content, calculated by 1H-NMR spectroscopy, was 0.13 mol%.

[0144] (Examples 1-3: Preparation of silicone rubber-based curable compositions) A silicone rubber-based curable composition was prepared as follows. First, a mixture of 90% vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) was pre-kneaded in the proportions shown in Table 1 below. Then, silica particles (C) were added to the mixture and kneaded further to obtain a compound (silicone rubber compound). Here, the mixing after the addition of silica particles (C) was carried out in two steps: the first step of mixing under a nitrogen atmosphere at 60-90°C for 1 hour for the coupling reaction, and the second step of mixing under a reduced pressure atmosphere at 160-180°C for 2 hours to remove the by-product (ammonia). After that, it was cooled, and the remaining 10% vinyl group-containing organopolysiloxane (A) was added in two parts and mixed for 20 minutes. Next, 100 parts by weight of the resulting mixture (silicone rubber compound) was mixed with organohydrogenpolysiloxane (B) (TC-25D) and platinum or platinum compound (E) (TC-25A) in the proportions shown in Table 1 below, and kneaded with a roll to obtain a silicone rubber-based curable composition.

[0145] (Comparative Example 1: Preparation of a silicone rubber-based curable composition) Vinyl group-containing organopolysiloxane (A) was kneaded alone for 5 minutes in the proportions shown in Table 1 below. Then, silica particles (C) were added to the mixture and kneaded for a further 2 hours to obtain a compound (silicone rubber compound). Next, 100 parts by weight of the resulting mixture (silicone rubber compound) was mixed with organohydrogenpolysiloxane (B) (TC-25D) and platinum or platinum compound (E) (TC-25A) in the proportions shown in Table 1 below, and kneaded with a roll to obtain a silicone rubber-based curable composition.

[0146] (Comparison 2: Preparation of silicone rubber-based curable compositions) The vinyl group-containing organopolysiloxane (A) was kneaded for 2 hours in the proportions shown in Table 1 below to obtain a compound (silicone rubber compound). Next, 100 parts by weight of the resulting mixture (silicone rubber compound) was mixed with organohydrogenpolysiloxane (B) (TC-25D) and platinum or platinum compound (E) (TC-25A) in the proportions shown in Table 1 below, and kneaded with a roll to obtain a silicone rubber-based curable composition.

[0147] [Table 1]

[0148] (Preparation of silicone rubber for evaluation) In Examples 1-3 and Comparative Examples 1 and 2, the obtained silicone rubber-based curable compositions were pressed at 170°C and 10 MPa for 10 minutes to form a 1 mm thick sheet and undergo primary curing. Subsequently, they were heated at 200°C for 4 hours to undergo secondary curing. As a result, sheet-like silicone rubber (cured product of the silicone rubber-based curable composition) was obtained.

[0149] The obtained sheet-like silicone rubber (sheet-like elastomer) was evaluated based on the following evaluation criteria. Tensile strength and elongation at break were measured using three samples, and the average of the three values ​​was used as the measurement. Tear strength was measured using five samples, and the average of the five values ​​was used as the measurement. For hardness, two samples were used, and measurements were taken with n=5 for each sample. The average of these 10 measurements was used as the measured value. The respective average values ​​are shown in Table 2.

[0150] [Table 2]

[0151] <Hardness: Durometer hardness> Six sheets of 1 mm thick silicone rubber were laminated to create a 6 mm thick test specimen. The hardness of the resulting test specimen was measured at 25°C according to JIS K6253 (1997) using a Type A durometer.

[0152] <Tear strength> Using the obtained 1 mm thick sheet of silicone rubber, crescent-shaped test specimens were prepared in accordance with JIS K6252 (2001), and the tear strength (TS) of the obtained crescent-shaped test specimens at 25°C was measured. The unit is N / mm.

[0153] <Elongation at break> Using the obtained 1 mm thick sheet of silicone rubber, a dumbbell-shaped No. 3 test specimen was prepared in accordance with JIS K6251 (2004), and the elongation at break (BE) at 25°C was measured for the obtained dumbbell-shaped No. 3 test specimen. The elongation at break was calculated as [gauge displacement (mm)] ÷ [initial gauge distance (20 mm)] × 100. The unit is %.

[0154] <Wear loss> A sheet sample with a thickness of 2 mm was prepared in the same manner as described above (preparation of silicone rubber for evaluation). Using the obtained samples, a Taber abrasion test was performed in accordance with JIS K7204. The abrasion wheel used was "CS-0+S42 Sandpaper Strip". When the weight of the sheet sample before the Taber abrasion test (g) was A and the weight of the sheet sample after the Taber abrasion test (g) was B, the abrasion loss (g) was calculated using formula AB. The two samples were evaluated, and the average values ​​of the calculated abrasion losses are shown in Table 2. In Table 2, "1>" means that the wear loss is greater than 1g.

[0155] The silicone rubber curable compositions of Examples 1 to 3 showed superior abrasion resistance compared to Comparative Examples 1 and 2. Among the examples, Examples 1 and 2 showed superior abrasion resistance, with a larger TS×BE ratio than Example 3. Such silicone rubber curable compositions can be suitably used for blade components, specifically wiper blades.

Claims

1. A silicone rubber-based curable composition used to form wear-resistant blade members (excluding resin movable members that constitute part of a robot), A vinyl group-containing polyorganosiloxane (A), Organohydrogenpolysiloxane (B) and Silica particles (C) surface-treated with a silane coupling agent (D), Platinum or platinum compound (E), (except when it contains graphite and perfluoroalkyl group-containing polydiorganosiloxanes), The content of the silica particles (C) is 50 parts by weight or less per 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), The silane coupling agent (D) includes a silane coupling agent having a hydrophobic group and a silane coupling agent having a vinyl group. The durometer hardness A of the cured product of the silicone rubber-based curable composition, measured according to the following procedure, is 39.5 or more and 69.8 or less. When the tear strength of the cured product of the silicone rubber-based curable composition, measured according to the following procedure, is denoted as TS (N / mm) and the elongation at break as BE (%), then TS and BE are 2.3 × 10⁻⁶. ４ Satisfying ≤ TS × BE, The abrasion loss of the cured product of the silicone rubber-based curable composition, as measured by the following procedure, is 0.23 g or less. A silicone rubber-based curable composition. (Procedure for measuring tear strength) Using the cured product of the silicone rubber-based curable composition, a crescent-shaped test specimen is prepared in accordance with JIS K6252 (2001), and the tear strength of the obtained crescent-shaped test specimen is measured at 25°C. The unit is N / mm. (Procedure for measuring elongation at break) Using the cured product of the silicone rubber-based curable composition, a dumbbell-shaped No. 3 test specimen was prepared in accordance with JIS K6251 (2004), and the elongation at break of the obtained dumbbell-shaped No. 3 test specimen was measured at 25°C. The elongation at break was calculated as [gauge displacement (mm)] ÷ [initial gauge distance (20 mm)] × 100. The unit is %. (Measurement procedure for durometer hardness A) A sheet-like test specimen is prepared using the cured product of the silicone rubber-based curable composition, and the durometer hardness A of the obtained sheet-like test specimen is measured at 25°C in accordance with JIS K6253 (1997). (Measurement procedure for wear loss) The silicone rubber-based curable composition is pressed at 170°C and 10 MPa for 10 minutes to form a 2 mm thick sheet and undergo primary curing, followed by secondary curing by heating at 200°C for 4 hours. A 2 mm thick sheet sample is then prepared using the resulting cured product. A Taber abrasion test is performed on the obtained sheet sample in accordance with JIS K7204, using "CS-0 + S42 SANDPAPER STRIP" as the abrasion wheel. When the weight of the sheet sample before the Taber abrasion test (g) is A and the weight of the sheet sample after the Taber abrasion test (g) is B, the abrasion loss (g) is calculated using the formula: A - B, and the average of the abrasion losses calculated for the two sheet samples is taken as the measured value.

2. A silicone rubber-based curable composition according to claim 1, A silicone rubber-based curable composition in which the silica particles (C) are present in an amount of 20 parts by weight or more per 100 parts by weight of the vinyl group-containing polyorganosiloxane (A).

3. A silicone rubber-based curable composition according to claim 1 or 2, A silicone rubber-based curable composition having a tear strength of 25 N / mm or more.

4. A silicone rubber-based curable composition according to any one of claims 1 to 3, A silicone rubber-based curable composition having a durometer hardness A of 30 or higher, as measured by the following procedure.

5. A silicone rubber-based curable composition according to any one of claims 1 to 4, A silicone rubber-based curable composition comprising a first vinyl group-containing linear organopolysiloxane (A1-1) in which the vinyl group-containing polyorganosiloxane (A) has two vinyl groups only at its terminal ends within the molecule and the amount of vinyl groups is 0.4 mol% or less.

6. A silicone rubber-based curable composition according to any one of claims 1 to 5, A silicone rubber-based curable composition in which the blade member is used as a component of a vehicle, electronic equipment, machine tool, or building.

7. A blade member comprising a cured product of a silicone rubber-based curable composition according to any one of claims 1 to 6.

Images