Elastomers and wearable devices using them

Abstract

To provide an elastomer with excellent conformability to uneven surfaces. [Solution] The present invention provides an elastomer that has been stretched to 50% according to a predetermined stretching operation. When measured using a hardness tester at 25°C in accordance with JIS K6253 (1997), the durometer hardness A of the elastomer at 50% stretching is measured. 50 However, it is an elastomer for wearable devices with a molecular weight between 20 and 80.

Description

Technical Field

[0001] The present invention relates to an elastomer and a wearable device using the same.

Background Art

[0002] Various studies have been made on elastomers for wearable devices. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes that polyurethane is used for the stretchable base material of a wearable device (paragraph 0031 of Patent Document 1, FIG. 2, etc.).

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 the unevenness followability of the elastomer described in Patent Document 1 above.

Means for Solving the Problems

[0005] The present inventor has found that the followability of the elastomer to the uneven surface can be controlled by using, as a guideline, the physical properties in the direction orthogonal to the stretching direction when the elastomer is stretched. As a result of intensive studies based on such findings, after adopting the hardness at the time of stretching of the elastomer as an index, it has been found that the unevenness followability of the elastomer can be improved by setting the hardness at the time of stretching, which is the index, to a predetermined value or less, and the present invention has been completed.

[0006] According to the present invention, An elastomer for wearable devices, The durometer hardness A of the elastomer at 50% elongation was measured using a hardness tester at 25°C in accordance with JIS K6253 (1997) after elongating the elastomer to 50% according to the elongation procedure described below. 50 However, an elastomer with a value between 20 and 80 is provided. (extension operation) (1) Prepare strip test pieces of a predetermined thickness from the elastomer. (2) Place both ends of the strip test piece between the chucks of the stretching machine. (3) The initial value D0 is defined as the distance between the chucks when the strip of test material changes from a loose state to a taut state. (4) The distance between the chucks is increased by a predetermined percentage relative to the initial value D0, and the strip test piece is held for 1 minute in a state where it has been stretched by a predetermined percentage.

[0007] Furthermore, the present invention provides a wearable device comprising the above-mentioned elastomer. [Effects of the Invention]

[0008] According to the present invention, an elastomer with excellent conformability to uneven surfaces and a wearable device using the same are provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram illustrating a method for measuring the elongation hardness of elastomers. [Figure 2] This is a schematic top view illustrating the structure of the extension machine. [Figure 3] This diagram illustrates a method for evaluating the conformability of elastomers. [Modes for carrying out the invention]

[0010] The outline of the elastomer of this embodiment will be described below.

[0011] The elastomer of this embodiment, when stretched to 50% according to the stretching operation described below, was measured using a hardness tester at 25°C in accordance with JIS K6253 (1997), yielded the following durometer hardness A of the elastomer at 50% stretch. 50 However, it is an elastomer for wearable devices that can have characteristics between 20 and 80.

[0012] (extension operation) (1) Prepare strip test pieces of a predetermined thickness from the elastomer. (2) Place both ends of the strip test piece between the chucks of the stretching machine. (3) The initial value D0 is defined as the distance between the chucks when the strip of test material changes from a loose state to a taut state. (4) The distance between the chucks is increased by a predetermined percentage relative to the initial value D0, and the strip test piece is held for 1 minute in a state where it has been stretched by a predetermined percentage.

[0013] In recent years, the standards for wearability in wearable devices have become increasingly higher, including requirements for stability and comfort. Focusing on this aspect of wearability, we hypothesized that we could improve wearability by enhancing the ability to conform to uneven surfaces and bumps on the body's surface and the surface of clothing worn on the body. Therefore, the inventors investigated and found that the conformability of the elastomer to uneven surfaces can be controlled by using the physical properties in a direction perpendicular to the direction of elongation when the elastomer is stretched as a guideline. Based on this finding, they conducted further investigations and found that by adopting the elongation hardness of the elastomer as an indicator and setting the elongation hardness, which is the indicator, below a predetermined value, the conformability of the elastomer to uneven surfaces can be improved, and it was found that the conformability to uneven surfaces can be stably evaluated. Furthermore, the inventors also discovered a method for measuring elongation hardness through their investigations.

[0014] According to the elastomer of this embodiment, the durometer hardness A of the elastomer when stretched to 50% 50By keeping the value below the above upper limit, it becomes possible to create an elastomer with excellent conformability to uneven surfaces.

[0015] The molded body comprising the elastomer of this embodiment can be applied, for example, to wearable devices that can be attached to the body or clothing. Examples of wearable devices include medical sensors that detect biological phenomena such as heart rate, electrocardiogram, blood pressure, and body temperature, healthcare devices, foldable displays, stretchable LED arrays, stretchable solar cells, stretchable antennas, stretchable batteries, actuators, and wearable computers. The above-mentioned wearable devices can be used as components for constructing stretchable and flexible movable members (stretchable members) such as stretchable electrodes, stretchable wiring, and stretchable substrates, as well as exterior members, etc. Among these, it is particularly suitable for use in wearable devices that are wrapped around the surface of the body or clothing. Furthermore, elastomers can be processed and molded into various shapes such as sheets, tubes, and bags.

[0016] Next, the properties of the elastomer of this embodiment will be described.

[0017] The elongated durometer hardness A of the elastomer (hereinafter sometimes simply referred to as "hardness") is measured when the elastomer is stretched to 50% according to the stretching operations shown in (1) to (4) above. The size of the strip test piece in (1) shall be, for example, width: 5 mm x length: 100 mm, thickness: 2 mm. The thickness may be 2 mm, but it may also be between 6 mm and 10 mm. (2) The stretcher can be a uniaxial stretcher for film. The stretcher may be manually operated. (3) A loosened strip of the test specimen means a state in which there is almost no stress from the strip of the test specimen at both ends between the chucks. A taut strip of the test specimen means a state in which there is a small amount of stress from the strip of the test specimen at both ends between the chucks. The specified percentage in (4) above shall be 50%, 100%, or 200%. The elongation hardness at 50% to 200% may be measured consecutively. The measurement location of the durometer hardness A of the above-mentioned (4) strip test piece is, for example, the central part of the strip test piece or its vicinity. Using one strip test piece, measurements may be taken with n = 5, and the average value of the measurements may be used as the measured value.

[0018] In the elastomer of the present embodiment, the durometer hardness A of the elastomer at 25°C measured in accordance with JIS K6253 (1997) at 50% elongation 50 The lower limit value may be, for example, 20 or more, preferably 25 or more, more preferably 30 or more. Thereby, the resilience during repeated use can be enhanced. On the other hand, the above A 50 The upper limit value is 80 or less, preferably 70 or less, more preferably 65 or less. Thereby, an elastomer excellent in concavo-convex followability can be realized. [[ID=​​​​​​​​​​​​​​​

[0021] In the elastomer of this embodiment, tensile stress M 100 The upper limit may be, for example, 7.0 MPa or less, preferably 6.0 MPa or less, and more preferably 5.0 MPa or less. This can improve the deformability of the elastomer. On the other hand, the tensile stress M 100 The lower limit may be 0.1 MPa or higher, preferably 0.5 MPa or higher, and more preferably 0.8 MPa or higher. This can improve the mechanical strength of the elastomer.

[0022] In the elastomer of this embodiment, tensile stress M 200 The upper limit may be, for example, 9.0 MPa or less, preferably 8.0 MPa or less, and more preferably 7.5 MPa or less. This can improve the deformability of the elastomer. On the other hand, the above tensile stress M 200 The lower limit may be 0.5 MPa or higher, preferably 1.0 MPa or higher, and more preferably 1.5 MPa or higher. This can improve the mechanical strength of the elastomer.

[0023] In the elastomer of this embodiment, ((tensile stress M 200 -Tensile stress M 100 ) / Tensile stress M 100 The upper limit of ((tensile stress M) × 100 is, for example, 110% or less, preferably 100% or less, and more preferably 90% or less. This allows for a balance of characteristics. On the other hand, the above ((tensile stress M) 200 -Tensile stress M 100 ) / Tensile stress M 100 The lower limit of ) × 100 is 10% or more, preferably 15% or more, and more preferably 20% or more. This can improve the deformability of the elastomer.

[0024] (Measurement conditions for tensile stress) Tensile stress M 100 This refers to the tensile stress of the elastomer at 100% elongation, measured in accordance with JIS K6251 (2004) at 25°C. Tensile stress M200 This refers to the tensile stress of the elastomer at 200% elongation, measured in accordance with JIS K6251 (2004) at 25°C.

[0025] In the elastomer of this embodiment, the upper limit of the tear strength TS0 may be, for example, 70 N / mm or less, preferably 68 N / mm or less, more preferably 65 N / mm or less, and even more preferably 60 N / mm or less. This allows for a balance of the various properties of the elastomer. On the other hand, the lower limit of the tear strength TS0 is 25 N / mm or more, preferably 30 N / mm or more, more preferably 35 N / mm or more, and even more preferably 38 N / mm or more. This improves the scratch resistance and mechanical strength of the elastomer.

[0026] (Measurement conditions for tear strength) Tear strength TS0: This refers to the tear strength of the elastomer measured at 25°C in accordance with JIS K6252 (2001).

[0027] In the elastomer of this embodiment, the upper limit of the elongation at break BE0 may be, for example, 1500% or less, preferably 1200% or less, more preferably 1000% or less, and even more preferably 900% or less. This allows for a balance in the properties of the elastomer. On the other hand, the lower limit of the elongation at break BE0 is 250% or more, preferably 300% or more, and more preferably 350% or more. This improves the high elasticity and durability of the elastomer.

[0028] (Measurement conditions for elongation at break) Elongation at break BE0: This is the elongation at break measured for the elastomer at 25°C (room temperature) in accordance with JIS K6251 (2004).

[0029] In this embodiment, the hardness, tensile stress, elongation at break, and tear strength can be controlled by appropriately selecting, for example, the type and amount of each component contained in the elastomer, and the method for preparing the composition for forming the elastomer. Among these, for example, appropriately controlling the type and blending ratio of the resin constituting the elastomer, the crosslinking density and crosslinking structure of the resin, and improving the blending ratio and dispersibility of the inorganic filler are examples of factors that can bring the hardness, tensile stress, elongation at break, and tear strength into desired numerical ranges.

[0030] The composition of the elastomer in this embodiment will be described below.

[0031] The above-mentioned elastomer may include silicone rubber, given its chemical stability and excellent thermal stability.

[0032] The above thermosetting elastomer can be composed of a cured product of a curable elastomer composition. Furthermore, the above silicone rubber can be composed of a cured product of a silicone rubber-based curable composition.

[0033] Furthermore, the molded article of this embodiment may contain any components that can exhibit various functions. For example, from the viewpoint of increasing mechanical strength, the elastomer may contain an inorganic filler. Known inorganic fillers can be used, but for example, silica particles can be used.

[0034] The following describes a case in which a silicone rubber-based curable composition is used as an example of the elastomer in this embodiment.

[0035] 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 of this embodiment.

[0036] The vinyl group-containing organopolysiloxane (A) may include a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0037] The above vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, which serve as crosslinking points during curing.

[0038] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but preferably it has two or more vinyl groups in the molecule and is 15 mol% or less, and more preferably 0.01 to 12 mol%. This optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) and ensures the formation of a network with each component described later. In this embodiment, "~" means that the numerical values ​​at both ends are included.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and specific gravity within the above-mentioned range, the heat resistance, flame retardancy, and chemical stability of the resulting silicone rubber can be improved.

[0043] The vinyl group-containing linear organopolysiloxane (A1) is preferably one having a structure represented by the following formula (1).

[0044] [ka]

[0045] In formula (1), R 1 The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a 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. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups, with vinyl being preferred. Examples of aryl groups having 1 to 10 carbon atoms include phenyl.

[0046] Also, R 2 The C1-C10 alkyl group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group having 1 to 10 carbon atoms. Examples of C1-C10 alkyl groups include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of C1-C10 alkenyl groups include vinyl, allyl, and butenyl groups. An example of a C1-C10 aryl group is the phenyl group.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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).

[0052] [ka]

[0053] 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.

[0054] Furthermore, it is preferable that the vinyl group-containing linear organopolysiloxane (A1) contains a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and a vinyl group content of 0.4 mol% or less, and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol%. By combining a first vinyl group-containing linear organopolysiloxane (A1-1) having a typical vinyl group content as the raw rubber raw material for silicone rubber, with a second vinyl group-containing linear organopolysiloxane (A1-2) having a high vinyl group content, the vinyl groups can be unevenly distributed, and the crosslinking density can be more effectively formed in the crosslinking network of the silicone rubber. As a result, the tear strength of the silicone rubber can be more effectively increased.

[0055] 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.

[0056] 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%.

[0057] 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.

[0058] 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.

[0059] Furthermore, the vinyl group-containing organopolysiloxane (A) may also include a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0060] <<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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] As the linear organohydrogenpolysiloxane (B1) described above, one having the structure represented by the following formula (2) is preferably used.

[0066] [ka]

[0067] In formula (2), R 4 The 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.

[0068] Also, R 5The 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.

[0069] 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.

[0070] 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.

[0071] Note that R in equation (2) 4 ,R 5 ,R 6 Examples of substituents include methyl groups and vinyl groups, and methyl groups are preferred from the viewpoint of preventing intramolecular crosslinking reactions.

[0072] 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.

[0073] Furthermore, linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more types.

[0074] 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.

[0075] Furthermore, the specific gravity of branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0076] 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.

[0077] Furthermore, the branched organohydrogenpolysiloxane (B2) is preferably the one shown in the following average composition formula (c).

[0078] Average composition formula (c) (H a (R 7 ) 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)

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] Furthermore, a specific example of a branched organohydrogenpolysiloxane (B2) is one having a structure represented by the following formula (3).

[0085] [ka]

[0086] 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.

[0087] Note that in equation (3), multiple R 7 These are independent of each other, and may be different from each other or the same.

[0088] Furthermore, in equation (3), "-O-Si≡" indicates that Si has a branched structure that extends in three dimensions.

[0089] Furthermore, branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more types.

[0090] 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).

[0091] <<Silica particles (C)>> The silicone rubber-based curable composition of this embodiment may contain silica particles (C).

[0092] 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.

[0093] 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.

[0094] 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.

[0095] <<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).

[0096] 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.

[0097] 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.

[0098] 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.

[0099] Examples of silane coupling agents (D) include those represented by the following formula (4).

[0100] 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.

[0101] 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.

[0102] 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).

[0103] 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.

[0104] 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.

[0105] <<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.

[0106] 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.

[0107] Platinum or platinum compound (E) may be used alone or in combination of two or more types.

[0108] The silicone rubber-based curable composition of this embodiment may contain an organic peroxide (H). The organic peroxide (H) is a component that acts as a catalyst. The amount of organic peroxide (H) added is a catalytic amount. The organic peroxide (H) can be used in place of organohydrogenpolysiloxane (B) and platinum or a platinum compound (E), or in combination with organohydrogenpolysiloxane (B) and platinum or a platinum compound (E).

[0109] Examples of organic peroxides (H) include ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, peroxyesters, and peroxydicarbonates. Specifically, examples include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-bis(2,5-t-butylperoxy)hexane, di-t-butyl peroxide, t-butyl perbenzoate, and 1,6-hexanediol-bis-t-butyl peroxycarbonate.

[0110] <<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).

[0111] 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.

[0112] 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.

[0113] 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.

[0114] In this embodiment, the upper limit of the silica particle (C) content may be, for example, 60 parts by weight or less, preferably 50 parts by weight or less, and more preferably 35 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 not particularly limited, but may be, for example, 20 parts by weight or more, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A).

[0115] The silane coupling agent (D) is preferably contained 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 makes it possible to reliably improve the dispersibility of silica particles (C) in a silicone rubber-based curable composition.

[0116] 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.

[0117] The content of platinum or platinum compound (E) refers to the catalytic amount and can be set as appropriate, but specifically, it is an amount such that the platinum group metal in this component is 0.01 to 1000 ppm by weight per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D), preferably an amount of 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.

[0118] The content of organic peroxide (H) represents the catalytic amount and can be set as appropriate, but specifically, for 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D), it is, for example, 0.001 parts by weight or more, preferably 0.005 parts by weight or more, and more preferably 0.01 parts by weight or more. This ensures a minimum strength as a cured product. Furthermore, the upper limit of the content of organic peroxide (H) is, for example, 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 3 parts by weight or less, for 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D). This suppresses the influence of by-products.

[0119] 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.

[0120] <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.

[0121] First, the components of the silicone rubber curable composition are uniformly mixed using any kneading device to prepare the silicone rubber curable composition.

[0122] [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).

[0123] 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).

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] By setting the conditions for the first and second steps as described above, the aforementioned effects can be obtained more significantly.

[0130] [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.

[0131] 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.

[0132] 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.

[0133] Furthermore, the mixing time is preferably, for example, 5 minutes to 1 hour, and more preferably 10 to 40 minutes.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] Furthermore, in this step [2], an organic peroxide (H) may be added instead of the organohydrogenpolysiloxane (B) and platinum or a platinum compound (E), or in combination with the organohydrogenpolysiloxane (B) and platinum or a platinum compound (E). The preferred conditions such as temperature and time when kneading the organic peroxide (H), and the equipment used, are the same as those when kneading the organohydrogenpolysiloxane (B) and platinum or a platinum compound (E).

[0138] [3] Next, silicone rubber is formed by curing the silicone rubber-based curable composition.

[0139] In this embodiment, the curing process of the silicone rubber-based curable resin 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 going through the above process, the silicone rubber of this embodiment can be obtained.

[0140] The inventors' research yielded the following findings: Reducing the amount of filler in silicone rubber can lower its hardness and tensile stress, but it also reduces its tear strength and thus its durability.

[0141] As a result of diligent research, we discovered that by appropriately selecting resin compositions such as vinyl group-containing organopolysiloxane (A), the crosslinking density and the uneven distribution of crosslinking structures can be controlled, thereby increasing the tear strength of silicone rubber while achieving low stress and low hardness over a wide strain range. We also found that the tensile strength of silicone rubber can be increased. Although the detailed mechanism is not yet clear, it is thought that by using a combination of high-vinyl group-containing organopolysiloxane and low-vinyl group-containing organopolysiloxane, the uneven distribution of crosslinking structures can be controlled, thus increasing the tear strength of silicone rubber while reducing hardness. In this way, by increasing the tear strength while maintaining other physical properties, the fracture energy of silicone rubber can be increased.

[0142] In this embodiment, the tensile stress, elongation at break, tensile strength, tear strength, and hardness can be controlled by appropriately selecting, for example, the type and amount of each component contained in the silicone rubber curable composition, the method for preparing the silicone rubber curable composition, and the method for producing silicone rubber. Among these, for example, using a combination of a low vinyl group-containing linear organopolysiloxane (A1-1) and a high vinyl group-containing linear organopolysiloxane (A1-2), using a vinyl group-containing organopolysiloxane (A) with vinyl groups at its ends to control the crosslinking density and uneven distribution of the crosslinking structure of the resin, the timing and ratio of the addition of the vinyl group-containing organopolysiloxane (A), the blending ratio of silica particles (C), surface modification of the silica particles (C) with a silane coupling agent (D), and the addition of water to ensure that the reaction between the silane coupling agent (D) and the silica particles (C) proceeds more reliably, are listed as factors for achieving the desired numerical range for the tensile stress, elongation at break, tensile strength, and tear strength.

[0143] In this embodiment, when measuring the tensile stress, elongation at break, tensile strength, and tear strength of the above-mentioned silicone rubber curable composition, the cured product of the silicone rubber curable composition can be used as the heating target and the measurement target. As this cured product, for example, a sheet-like silicone rubber (cured product of the silicone rubber curable composition) obtained by pressing the silicone rubber curable composition at 160°C and 10 MPa for 20 minutes to form a sheet with a thickness of 1 mm and performing primary curing, followed by heating at 200°C for 4 hours to perform secondary curing, may be used.

[0144] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. [Examples]

[0145] 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.

[0146] 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)

[0147] (Organohydrogenpolysiloxane (B)) Momentive Corporation: "TC-25D"

[0148] (Silica particles (C)) • Silica particles (C): Silica microparticles (particle size 7nm, specific surface area 300m²) 2 / g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL300"

[0149] (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)"

[0150] (Platinum or platinum compound (E)) Momentive Corporation: "TC-25A"

[0151] (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 × 105 Furthermore, the vinyl group content, calculated by 1H-NMR spectroscopy, was 0.04 mol%.

[0152] [ka]

[0153] [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-tetramethyl2,4,6,8-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) 5 Mw = 5, 0 × 10 5 Furthermore, the vinyl group content, calculated by 1H-NMR spectroscopy, was 0.93 mol%. [ka]

[0154] (Example 1: Preparation of a silicone rubber-based curable composition) In Example 1, a silicone rubber-based curable composition was prepared as follows. First, a mixture of 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 kneaded product (silicone rubber compound). Here, the mixing after the addition of silica particles (C) was carried out in two steps: the first step involved mixing under a nitrogen atmosphere at 60-90°C for 1 hour for the coupling reaction, and the second step involved mixing under a reduced pressure atmosphere at 160-180°C for 2 hours to remove by-products (ammonia). After that, the mixture was cooled and mixed for 20 minutes. Next, 1.81 parts by weight of organohydrogenpolysiloxane (TC-25D) and 0.5 parts by weight of platinum or platinum compound (TC-25A) were added to 100 parts by weight of the obtained mixture (silicone rubber compound), and the mixture was kneaded with a roller to obtain the silicone rubber-based curable composition of Example 1.

[0155] (Example 2: Preparation of a silicone rubber-based curable composition) In Example 2, a silicone rubber-based curable composition was prepared in the same manner as in Example 1. First, a mixture of vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) was pre-kneaded in the proportions shown in Table 1. Then, silica particles (C) were added to the mixture and kneaded further to obtain a kneaded product (silicone rubber compound). Here, the kneading after the addition of silica particles (C) was carried out in the same manner as in Example 1. Next, 3.77 parts by weight of organohydrogenpolysiloxane (TC-25D) and 0.5 parts by weight of platinum or platinum compound (TC-25A) were added to 100 parts by weight of the obtained mixture (silicone rubber compound), and the mixture was kneaded with a roller to obtain the silicone rubber-based curable composition of Example 2.

[0156] (Example 3: Preparation of a silicone rubber-based curable composition) In Example 3, a silicone rubber-based curable composition was prepared in the same manner as in Example 1. First, a mixture of vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) was pre-kneaded in the proportions shown in Table 1. Then, silica particles (C) were added to the mixture and kneaded further to obtain a kneaded product (silicone rubber compound). Here, the kneading after the addition of silica particles (C) was carried out in the same manner as in Example 1. Next, 4.53 parts by weight of organohydrogenpolysiloxane (TC-25D) and 0.5 parts by weight of platinum or platinum compound (TC-25A) were added to 100 parts by weight of the obtained mixture (silicone rubber compound), and the mixture was kneaded with a roller to obtain the silicone rubber-based curable composition of Example 3.

[0157] (Example 4: Preparation of a silicone rubber-based curable composition) In Example 4, a silicone rubber-based curable composition was prepared in the same manner as in Example 1. First, a mixture of vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) was pre-kneaded in the proportions shown in Table 1. Then, silica particles (C) were added to the mixture and kneaded further to obtain a kneaded product (silicone rubber compound). Here, the kneading after the addition of silica particles (C) was carried out in the same manner as in Example 1. Next, 100 parts by weight of the resulting mixture (silicone rubber compound) was mixed with 2.26 parts by weight of organohydrogen polysiloxane (TC-25D) and 0.5 parts by weight of platinum or platinum compound (TC-25A), and kneaded with a roll to obtain the silicone rubber-based curable composition of Example 4.

[0158] (Example 5: Preparation of a silicone rubber-based curable composition) In Example 5, a silicone rubber-based curable composition was prepared in the same manner as in Example 1. First, a mixture of vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) was pre-kneaded in the proportions shown in Table 1. Then, silica particles (C) were added to the mixture and kneaded further to obtain a kneaded product (silicone rubber compound). Here, the kneading after the addition of silica particles (C) was carried out in the same manner as in Example 1. Next, 4.53 parts by weight of organohydrogenpolysiloxane (TC-25D) and 0.5 parts by weight of platinum or platinum compound (TC-25A) were added to 100 parts by weight of the obtained mixture (silicone rubber compound), and the mixture was kneaded with a roller to obtain the silicone rubber-based curable composition of Example 5.

[0159] [Table 1]

[0160] (Making silicone rubber) In Examples 1 to 5, the obtained silicone rubber-based curable compositions were pressed at 170°C and 10 MPa for 10 minutes to form a 2 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 as a sheet-like elastomer.

[0161] [Comparative Example 1] A sheet of chloroprene rubber (2mm thick, 500mm wide x 500mm long, Rubber Co. product code 10037) purchased from Fuso Rubber Industry Co., Ltd. was used as a sheet-type elastomer. [Comparative Example 2] A sheet of fluororubber (2mm thick, 300mm wide x 300mm long, Rubber Co. product code 10001) purchased from Fuso Rubber Industry Co., Ltd. was used as a sheet-type elastomer.

[0162] The sheet-like elastomers obtained in the examples and comparative examples were evaluated based on the following evaluation criteria.

[0163] (hardness) The obtained 2 mm thick sheet-like elastomer was processed to create 10 strip-shaped test pieces (Figure 1(a)) with a width of 5 mm, a length of 100 mm, and a thickness of 2 mm. The obtained strip test specimen 10 was placed on a glass slide so that its top view shape was rectangular. With both ends of the strip test specimen 10 loosened without being pulled, the hardness A0 of the center 30 in the width direction of the strip test specimen 10 in its unstretched state at 25°C was measured using a hardness tester 20 (Teclock Co., Ltd., product name: Automatic constant pressure load device for durometer GS-610). The hardness was measured by pressing the base of the hardness tester 20, which has an indenter, parallel to the rectangular surface of the strip test piece 10.

[0164] Next, we prepared the manual stretcher 100 (uniaxial stretcher for film) shown in Figure 2. The manual stretcher 100 includes a chuck 102 which is a fixed end and a chuck 104 which is movable in the axial direction of the shaft 110. Both ends of a sheet-shaped film can be fixed to the chucks 102 and 104. With the film fixed, the chuck 104 moves relative to the chuck 102 in the axial direction. Between one fixed end (chuck 102) and the other fixed end 112, there is a shaft 110 fixed to the fixed end 112, and guides 106 and 108 are positioned parallel to the shaft 110 and on both sides thereof. As a result, the chuck 104 moves along the two guides, allowing for more precise axial movement. The chuck 104 can be moved axially to a predetermined position, and after setting the distance between the chucks to a predetermined value, the chuck 104 can be fixed to the guides 106 and 108 by the fixing parts 114 and 116.

[0165] Next, both ends of the strip test specimen 10 were placed in the chucks 102 and 104 of the manual stretcher 100, respectively, and the strip test specimen 10 was stretched. The distance between the chucks when the strip test specimen 10 went from a loose state to a taut state was defined as the initial value D0 (40 mm) (Figure 1(b)).

[0166] Next, using the manual stretcher 100, the distance D between the chucks is measured. x The strip test piece 10 was stretched to 60 mm and held for 1 minute. Then, at 25°C, the hardness A at 50% elongation was measured in the central part 30 of the strip test piece 10 in accordance with JIS K6253 (1997). 50 The hardness was measured using a hardness tester 20 (Figure 1(c)). Next, using the manual stretcher 100, the distance D between the chucks is measured. x The strip test piece 10 was stretched to 80 mm and held for 1 minute. Then, at 25°C, the hardness A at 100% elongation was measured in the central part 30 of the strip test piece 10 in accordance with JIS K6253 (1997). 100 It was measured with a hardness tester (20). Next, using the manual stretcher 100, the distance D between the chucks is measured. xThe strip test piece 10 was extended until it reached 120 mm, held for 1 minute, and then at 25°C, in accordance with JIS K6253 (1997), the hardness A at 200% elongation was measured at the center 30 of the strip test piece 10 using a hardness meter 20. 200 For hardness A0, A

[0167] For A 50 and A 100 and A 200 one sample (strip test piece) was used for each, and measurements were taken with n = 5 for each sample, and the average value of the measurements was used as the measured value. The respective average values are shown in Table 2.

[0168]

Table 2

[0169]

Table 3

[0170] The "-" in Table 3 means that it could not be measured due to breakage.

[0171] For tensile stress and elongation at break, the tests were performed on 3 samples, and the average of the 3 values was used as the measured value. For tear strength, the tests were performed on 5 samples, and the average of the 5 values was used as the measured value. The respective average values are shown in Table 3.

[0172] <Tear strength> Using the obtained sheet-shaped elastomer with a thickness of 2 mm, a crescent-shaped test piece was prepared at 25°C in accordance with JIS K6252 (2001), and the tear strength of the obtained crescent-shaped test piece was measured. The unit is N / mm.

[0173] <Tensile stress> Using the obtained 2 mm thick sheet-like elastomer, a dumbbell-shaped No. 3 test specimen was prepared at 25°C in accordance with JIS K6251 (2004), and the tensile stress M of the obtained dumbbell-shaped No. 3 test specimen at 100% elongation was measured at a tensile speed of 500 mm / min. 100 (100% modulus), tensile stress M at 200% elongation 200 The (200% modulus) was measured. The unit is MPa.

[0174] <Elongation at break> Using the obtained 2 mm thick sheet-like elastomer, a dumbbell-shaped No. 3 test specimen was prepared at 25°C in accordance with JIS K6251 (2004), and the elongation at break of the obtained dumbbell-shaped No. 3 test specimen was measured. The elongation at break was calculated as [chuck travel distance (mm)] ÷ [initial chuck distance (60 mm)] × 100. The unit is %.

[0175] <Followability> First, we prepared the following sheet-like test pieces 50, a concave substrate 60, and a Kiriyama funnel 70. (Sheet-shaped test piece 50) Using the sheet-like elastomers of each example and comparative example, sheet-like test specimens 50 measuring 15 cm square and 0.5 mm thick were prepared. The top view shape of the sheet-like test specimens 50 was square. (Concave substrate 60) A concave substrate 60 was prepared, in which a groove 62 was formed in the depth direction from the substrate surface. The depth D of the groove 62 was set to 2 mm (Figure 3(a)), and the diameter (width W) of the groove 62 was set to 20 mm (Figure 3(b)). As shown in Figure 3(b), the top view shape of the concave substrate 60 is rectangular, and the top view shape of the concave groove 62 is circular. Figure 3(b) is a view taken along arrow AA in Figure 3(a) (a cross-sectional view taken in a direction perpendicular to the top view direction). (Kiriyama Rohto 70) For the Kiriyama Funnel 70, model number S-60 was used. The Kiriyama Funnel 70 had an inner width of 85 mm at the mouth and an inner height H of 53 mm.

[0176] Next, a sheet-like test piece 50 was placed on the prepared concave substrate 60 so as to cover the groove 62. Then, the mouth of the Kiriyama funnel 70 was pressed against the periphery of the sheet-like test piece 50 (Figure 3(a)).

[0177] Next, the pressure inside the mouth of the Kiriyama funnel 70 was reduced to 300 mmHg (Figures 3(c) to 3(e)). Under this reduced pressure, the conformability of the sheet-like test piece 50 to the inner wall of the funnel mouth was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 4.

[0178] (Evaluation Criteria) Figure 3(c): When the pressure is reduced, the sheet-like test piece 50 expands and reaches the entire oral wall, which is marked with ◎. Figure 3(d): When it reaches a part of the upper surface of the oral wall but not the entire surface, it is marked with ○. Figure 3(e): When it does not reach the upper surface of the oral wall, it is marked with ×.

[0179] [Table 4]

[0180] The elastomers (silicone rubber) of Examples 1 to 5 were found to have superior conformability to uneven surfaces compared to Comparative Examples 1 to 2. These elastomers of Examples 1 to 5 are expected to be suitably used in wearable devices requiring conformability, particularly in stretchable components of wearable devices. [Explanation of Symbols]

[0181] 10 strip test pieces 20 Hardness meter 30 Center 50 sheet-shaped test specimens 60 Concave substrates 62 grooves 70 Kiriyama Rohto 100 manual stretching machine 102 Chuck 104 Chuck 106 Guide 108 Guide 110 axis 112 Fixed end 114 Fixing part 116 Fixing part

Claims

1. An elastomer for wearable devices, The durometer hardness A of the elastomer at 50% elongation was measured using a hardness tester at 25°C in accordance with JIS K6253 (1997) after the elastomer was stretched to 50% according to the stretching procedure described below. ５０ However, it is an elastomer with a value between 20 and 80. (Extension operation) (1) Prepare a strip of test material of a predetermined thickness from the elastomer. (2) Place both ends of the strip test piece between the chucks of the stretching machine. (3) The distance between the chucks when the strip of test material changes from a loose state to a taut state is the initial value D. ０ Let's assume that. (4) Initial value D ０ The distance between the chucks is increased by a predetermined percentage, and the strip of test material is held in this stretched state for one minute.

2. The elastomer according to claim 1, The durometer hardness A of the elastomer at 100% elongation was measured using a hardness tester at 25°C in accordance with JIS K6253 (1997) after the elastomer was stretched to 100% according to the stretching procedure described above. １００ However, it is an elastomer with a pH between 25 and 85.

3. The elastomer according to claim 1 or 2, The durometer hardness A of the elastomer at 200% elongation was measured using a hardness tester at 25°C in accordance with JIS K6253 (1997) after the elastomer was stretched to 200% according to the above stretching procedure. ２００ However, it is an elastomer with a value between 30 and 90.

4. An elastomer according to any one of claims 1 to 3, The tensile stress M in the elastomer at 100% elongation, measured at 25°C in accordance with JIS K6251 (2004). １００ However, the elastomer has a pressure of 0.1 MPa or more and 7.0 MPa or less.

5. An elastomer according to any one of claims 1 to 3, The tensile stress M in the elastomer at 200% elongation, measured at 25°C in accordance with JIS K6251 (2004). ２００ However, the elastomer has a pressure of 0.5 MPa or more and 9.0 MPa or less.

6. An elastomer according to any one of claims 1 to 5, ((M ２００ - M １００ ) / M １００ ) × 100 is 10% or more and 110% or less, an elastomer. The above M １００ : The tensile stress M in the elastomer when stretched to 100%, measured at 25°C in accordance with JIS K6251 (2004). １００ This indicates. The above M ２００ : The tensile stress M in the elastomer when stretched to 200%, measured at 25°C in accordance with JIS K6251 (2004). ２００ This indicates.

7. An elastomer according to any one of claims 1 to 6, An elastomer having a tear strength of 25 N / mm or more when unstretched, measured at 25°C in accordance with JIS K6252 (2001).

8. An elastomer according to any one of claims 1 to 7, An elastomer composed of silicone rubber.

9. An elastomer according to any one of claims 1 to 8, Elastomer containing inorganic fillers.

10. An elastomer according to any one of claims 1 to 9, Elastomers used as stretchable components for wearable devices.

11. A wearable device comprising the elastomer described in any one of claims 1 to 10.

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