JP2018172634A - Elastomer, and molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elastomer excellent in heat resistance and durability.SOLUTION: ((tensile strength S3-tensile strength S0)/tensile strength S0)×100 found by measuring an elastomer of the present embodiment under the following condition is -80% of less. (condition): The tensile strength S0 is a tensile strength found by measuring the elastomer in accordance with JIS K6251(2004) of the elastomer at 25°C without further heating, and the tensile strength S3 is a tensile strength found by measuring the elastomer in accordance with JIS K6251(2004) of the elastomer at 200°C after holding at 200°C for 30 min.SELECTED DRAWING: None

Description

  The present invention relates to an elastomer and a molded body.

  Various studies have been made on elastomers for medical use. As this type of technology, for example, a thermoplastic elastomer for medical tube use described in Patent Document 1 is known. Many of the thermoplastic elastomers for medical tubes are severely softened at a temperature higher than about 100 ° C., so that they may not exhibit sufficient performance under steam sterilization.

JP 2005-330326 A

  However, as a result of examination by the present inventor, there is room for improvement in terms of heat resistance and durability because thermoplastic elastomers for medical tube applications described in the above-mentioned document 1 cause characteristic fluctuations in a high temperature environment. There was found.

  As a result of intensive investigations by focusing on the behavior of physical property changes due to heating of the elastomer, the present inventor, by using the heat change physical property variable as an index, expressed by the degree of physical property change at room temperature and high temperature, It has been found that the state of properties of an elastomer can be evaluated, which varies due to the heat received by the elastomer from the environment of use.

Further examination revealed that the use of tensile strength as a heat-change physical property variable enables stable evaluation of the state of properties such as heat resistance and durability of the elastomer in a high temperature environment.
The present inventor has conducted further research based on such knowledge, adopting a heat change physical property variable based on tensile strength as an index, and reducing the heat change physical property variable within a predetermined range, under a high temperature environment. The inventors have found that the heat resistance and durability of the elastomer can be prevented from being lowered, and have completed the present invention.

According to the present invention,
An elastomer having ((tensile strength S3−tensile strength S0) / tensile strength S0) × 100 measured under the following conditions is −80% or more.
(conditions)
Tensile strength S0: The elastomer is subjected to a tensile strength measured in accordance with JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Tensile strength S3: The tensile strength measured at 200 ° C. according to JIS K6251 (2004) of the elastomer after holding at 200 ° C. for 30 minutes.

  Moreover, according to this invention, a molded object provided with the said elastomer is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the elastomer and the molded object which were excellent in heat resistance and durability in a high temperature environment are provided.

  An outline of the elastomer of this embodiment will be described.

In the elastomer of the present embodiment, ((tensile strength S3−tensile strength S0) / tensile strength S0) × 100 can be −80% or more.
(Tensile strength conditions)
Tensile strength S0: The elastomer is subjected to a tensile strength measured in accordance with JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Tensile strength S3: The tensile strength measured at 200 ° C. according to JIS K6251 (2004) of the elastomer after holding at 200 ° C. for 30 minutes.

The present inventor has focused on the behavior of the physical property change due to heating of the elastomer, and as a result of intensive studies, it has been used by using the thermal change physical property variable as an index, which is represented by the degree of physical property change between room temperature and high temperature. It has been found that the state of properties of an elastomer that varies due to the heat received by the elastomer from the environment can be evaluated. Further examination revealed that the use of tensile strength as a heat-change physical property variable enables stable evaluation of the state of properties such as heat resistance and durability of the elastomer in a high temperature environment.
As a result of further investigation based on such knowledge, it was found that if the heat change physical property variable is too large, the physical property fluctuates greatly after heating like a plastic elastomer. Moreover, even when a thermosetting elastomer is used, it has been found that the heat change property variable may not be measured when it is melted by heating like polyurethane. Therefore, by selecting an appropriate thermosetting elastomer material from various elastomers and reducing the heat change physical property variable based on the tensile strength within a specified range, the heat resistance and durability of the elastomer will be reduced in a high temperature environment. It was found that can be suppressed.

  According to the elastomer of this embodiment, by setting (tensile strength S3−tensile strength S0) / tensile strength S0) × 100 to the above lower limit value or more, an elastomer excellent in heat resistance and durability in a high temperature use environment is realized. It becomes possible to do. In addition, since such an elastomer suppresses fluctuations in properties due to heat, it can be suitably used for molded articles for various applications such as applications where heat treatment is performed and applications used in a high temperature environment. .

  As a molded object provided with the elastomer of this embodiment, it can use for production equipment uses, such as medical uses, such as a medical tube, the object for motor vehicles, a vibration isolator, a seismic isolation material, and a food hose, for example.

  Next, the characteristic of the elastomer of this embodiment is demonstrated.

  In the elastomer of the present embodiment, the upper limit value of ((tensile strength S3−tensile strength S0) / tensile strength S0) × 100 is not particularly limited, but is, for example, −0% or less, preferably −20% or less. More preferably, it may be −30% or less. On the other hand, the lower limit value of ((tensile strength S3−tensile strength S0) / tensile strength S0) × 100 is, for example, −80% or more, preferably −70% or more, and more preferably −65%. That's it. Thereby, the change of the mechanical strength and breaking energy of an elastomer under a high temperature use environment can be suppressed.

  In the elastomer of the present embodiment, the upper limit value of ((tensile strength S2−tensile strength S0) / tensile strength S0) × 100 is not particularly limited, but is, for example, −0% or less, preferably −10% or less. More preferably, it may be -20% or less. On the other hand, the lower limit of ((tensile strength S2−tensile strength S0) / tensile strength S0) × 100 is, for example, −60% or more, preferably −55% or more, and more preferably −50%. That's it. Thereby, the change of the mechanical strength and breaking energy of an elastomer can be suppressed under the use environment from a comparatively high temperature to a high temperature region.

  In the elastomer of the present embodiment, the upper limit value of ((tensile strength S1−tensile strength S0) / tensile strength S0) × 100 is not particularly limited, but is, for example, −0% or less, and preferably −10% or less. More preferably, it may be -15% or less. On the other hand, the lower limit of the above ((tensile strength S1−tensile strength S0) / tensile strength S0) × 100 is −50.0% or more, preferably −40% or more, more preferably −35%. That's it. Thereby, changes in mechanical strength and breaking energy of the elastomer can be suppressed under a relatively high temperature use environment.

  In the elastomer of the present embodiment, the upper limit value of the tensile strength S0 may be, for example, 15 MPa or less, preferably 14 MPa or less, more preferably 13 MPa or less, and further preferably 12 MPa or less. Thereby, the flexibility of the elastomer at room temperature can be increased. On the other hand, the lower limit value of the tensile strength S0 is 4.0 MPa or more, preferably 5.0 MPa or more, more preferably 6.0 MPa or more, and further preferably 7.0 MPa or more. Thereby, the mechanical strength of the elastomer at room temperature can be improved. Further, the breaking energy of the elastomer can be increased.

(Measurement conditions of tensile strength)
Tensile strength S0: The elastomer is subjected to a tensile strength measured in accordance with JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Tensile strength S1: It is set as the tensile strength measured according to JIS K6251 (2004) of the elastomer at 100 ° C. after being held at 100 ° C. for 30 minutes.
Tensile strength S2: The tensile strength measured at 150 ° C. according to JIS K6251 (2004) of the elastomer after holding at 150 ° C. for 30 minutes.
Tensile strength S3: The tensile strength measured at 200 ° C. according to JIS K6251 (2004) of the elastomer after holding at 200 ° C. for 30 minutes.

  In the elastomer of the present embodiment, the upper limit value of ((breaking elongation BE3−breaking elongation BE0) / breaking elongation BE0) × 100 is not particularly limited, but is, for example, −0% or less, preferably −20% or less. More preferably, it may be −30% or less. On the other hand, the lower limit of the above ((breaking elongation BE3−breaking elongation BE0) / breaking elongation BE0) × 100 is, for example, −85.5% or more, preferably −75% or more, more preferably −. 65% or more. Thereby, the high elasticity of an elastomer under high temperature use environment and the change of durability can be suppressed.

  In the elastomer of the present embodiment, the upper limit value of ((breaking elongation BE2−breaking elongation BE0) / breaking elongation BE0) × 100 is not particularly limited, but is, for example, −0% or less, preferably −20% or less. More preferably, it may be −30% or less. On the other hand, the lower limit of the above ((breaking elongation BE2−breaking elongation BE0) / breaking elongation BE0) × 100 is, for example, −60% or more, preferably −55% or more, more preferably −51%. That's it. Thereby, the change of the high elasticity and durability of the elastomer in the use environment between comparatively high temperature to a high temperature area | region can be suppressed.

  In the elastomer of the present embodiment, the upper limit value of ((breaking elongation BE1−breaking elongation BE0) / breaking elongation BE0) × 100 is not particularly limited, but is, for example, −0% or less, preferably −10% or less. More preferably, it may be -15% or less. On the other hand, the lower limit of the above ((breaking elongation BE1−breaking elongation BE0) / breaking elongation BE0) × 100 is, for example, −50% or more, preferably −40% or more, more preferably −35%. That's it. Thereby, the change of the high elasticity and durability of an elastomer can be suppressed in a comparatively high temperature use environment.

  In the elastomer of the present embodiment, the upper limit value of the breaking elongation BE0 may be, for example, 1500% or less, preferably 1200% or less, more preferably 1000% or less, and still more preferably 800% or less. Thereby, the mechanical strength of the elastomer at room temperature can be improved. On the other hand, the lower limit of the breaking elongation BE0 is 200% or more, preferably 250% or more, more preferably 300% or more, and further preferably 400% or more. Thereby, the high elasticity and durability of the elastomer at room temperature can be improved.

(Measurement conditions of elongation at break)
Elongation at break BE0: The elastomer is subjected to the elongation at break measured according to JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Elongation at break BE1: It is set as the elongation at break measured according to JIS K6251 (2004) of the elastomer at 100 ° C. after being held at 100 ° C. for 30 minutes.
Elongation at break BE2: The elongation at break is measured according to JIS K6251 (2004) of the elastomer at 150 ° C. after being held at 150 ° C. for 30 minutes.
Breaking elongation BE3: The elongation at break of the elastomer is measured at 200 ° C. for 30 minutes and then measured at 200 ° C. according to JIS K6251 (2004).

  In the elastomer of the present embodiment, the upper limit value of the tear strength TS2 is not particularly limited, but may be, for example, 50 N / mm or less, preferably 30 N / mm or less, and more preferably 20 N / mm or less. On the other hand, the lower limit value of the tear strength TS2 is, for example, 5 N / mm or more, preferably 5.3 N / mm or more, and more preferably 5.5 N / mm or more. This can improve the scratch resistance and mechanical strength of the elastomer in a use environment between a relatively high temperature and a high temperature region.

(Tearning strength measurement conditions)
Tear strength TS0: The elastomer is not subjected to further heat treatment, and is the tear strength measured in accordance with JIS K6252 (2001) of the elastomer at room temperature of 25 ° C.
Tear strength TS1: It is set as the tear strength measured in accordance with JIS K6252 (2001) of the elastomer at 100 ° C. after being held at 100 ° C. for 30 minutes.
Tear strength TS2: Tear strength measured at 150 ° C. according to JIS K6252 (2001) of the elastomer after holding at 150 ° C. for 30 minutes.
Tear strength TS3: Tear strength measured at 200 ° C. according to JIS K6252 (2001) of the elastomer after holding at 200 ° C. for 30 minutes.

In elastomer of the present embodiment, the tensile limit of the stress _{M 100} 0, for example, not more than 7.0 MPa, preferably not more than 6.0 MPa, more preferably not more than 5.0 MPa, more preferably 4. It may be 0 MPa or less. Thereby, the deformability of the elastomer at room temperature can be improved. On the other hand, the lower limit of the tensile stress _{M 100} 0 is at 0.5MPa or more, preferably not less than 1.0 MPa, more preferably at least 1.5 MPa. Thereby, the mechanical strength of the elastomer at room temperature can be improved.

(Measurement conditions of tensile stress)
Tensile stress M ₁₀₀ 0: The elastomer is subjected to a tensile stress at 100% elongation of the elastomer at room temperature of 25 ° C. without further heat treatment.
Tensile stress M ₁₀₀ 1: After holding the elastomer at 100 ° C. for 30 minutes, it is defined as a tensile stress at 100 ° C. when the elastomer is 100% stretched.
Tensile stress _{M 100} 2: with respect to the elastomer, 0.99 ° C., after 30 minutes holding, at 0.99 ° C., and the tensile stress at 100% elongation of the elastomer.
Tensile stress M ₁₀₀ 3: The tensile stress at 100% elongation of the elastomer at 200 ° C. after being held at 200 ° C. for 30 minutes.

  In the elastomer of the present embodiment, the upper limit value of durometer hardness A defined by JIS K6253 (1997) may be, for example, 80 or less, preferably 75 or less, and more preferably 70 or less. Thereby, the balance of various physical properties of an elastomer can be aimed at. On the other hand, the lower limit of the hardness A is 20 or more, preferably 30 or more, more preferably 35 or more, and further preferably 40 or more. Thereby, the mechanical strength of the elastomer at room temperature can be improved, deformation from an external force can be suppressed, and shape retention can be enhanced.

  In this embodiment, for example, by appropriately selecting the type and blending amount of each component contained in the elastomer, the preparation method of the composition for forming the elastomer, etc., the tensile stress, elongation at break, tensile strength, tearing It is possible to control the intensity. 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, improving the blending ratio of the inorganic filler and the dispersibility of the inorganic filler, etc. Are included as elements for bringing the tensile stress, elongation at break, tensile strength, and tear strength into desired numerical ranges.

  Hereinafter, the composition of the elastomer of this embodiment will be described.

  The elastomer may include one or more thermosetting elastomers selected from the group consisting of silicone rubber and fluororubber. This elastomer can contain silicone rubber from the viewpoint of being chemically stable and excellent in thermal stability.

  The said thermosetting elastomer can be comprised with the hardened | cured material of a curable elastomer composition. Moreover, the said silicone rubber can be comprised with the hardened | cured material of a silicone rubber type curable composition.

  Moreover, the arbitrary component which can exhibit various functions may be added to the molded object of this embodiment. For example, from the viewpoint of increasing the mechanical strength, the elastomer can include an inorganic filler. As the inorganic filler, known materials can be used, and for example, silica particles can be used.

  Hereinafter, a case where a silicone rubber-based curable composition is used as the silicone rubber which is an example of the elastomer of the present embodiment will be described.

  The silicone rubber-based curable composition of the present embodiment can contain a vinyl group-containing organopolysiloxane (A). The vinyl group-containing organopolysiloxane (A) is a polymer that is a main component of the silicone rubber-based curable composition of the present embodiment.

  The vinyl group-containing organopolysiloxane (A) can include a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

  The vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains a vinyl group, and this vinyl group serves as a crosslinking point during curing.

  The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited. For example, the vinyl group-containing linear organopolysiloxane preferably has 2 or more vinyl groups in the molecule and 15 mol% or less. More preferably, it is 0.01-12 mol%. Thereby, the quantity of the vinyl group in vinyl group containing linear organopolysiloxane (A1) is optimized, and formation of the network with each component mentioned later can be performed reliably. In this embodiment, “to” means to include numerical values at both ends thereof.

  In addition, in this specification, vinyl group content is the mol% of a vinyl group containing siloxane unit when all the units which comprise a vinyl group containing linear organopolysiloxane (A1) are 100 mol%. . However, one vinyl group is considered for one vinyl group-containing siloxane unit.

  The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but for example, it is preferably in the range of about 1000 to 10000, more preferably about 2000 to 5000. In addition, a polymerization degree can be calculated | required as a number average polymerization degree (or number average molecular weight) of polystyrene conversion in GPC (gel permeation chromatography) which used chloroform as a developing solvent, for example.

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

  By using a vinyl group-containing linear organopolysiloxane (A1) having a polymerization degree and specific gravity within the above ranges, the resulting silicone rubber has heat resistance, flame retardancy, chemical stability, etc. Can be improved.

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

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 obtained by combining these. As a C1-C10 alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned, for example, Among these, a methyl group is preferable. As a C1-C10 alkenyl group, a vinyl group, an allyl group, a butenyl group etc. are mentioned, for example, Among these, a vinyl group is preferable. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

R ² is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group obtained by combining these. As a C1-C10 alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned, for example, Among these, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

R ³ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group obtained by combining these. As a C1-C8 alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned, for example, Among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group.

Furthermore, examples of the substituent for R ¹ and R ² in formula (1) include a methyl group and a vinyl group. Examples of the substituent for R ³ include a methyl group.

In the formula (1), a plurality of R ¹ are independent from each other and may be different from each other or the same. The same applies to R ² and R ³ .

  Further, m and n are the number of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by the formula (1), m is an integer of 0 to 2000, and n is 1000 to 10,000. Is an integer. m is preferably 0 to 1000, and n is preferably 2000 to 5000.

  Moreover, as a specific structure of a vinyl group containing linear organopolysiloxane (A1) represented by Formula (1), what is represented, for example by following formula (1-1) is mentioned.

In Formula (1-1), R ¹ and R ² are each independently a methyl group or a vinyl group, and at least one is a vinyl group.

  Furthermore, the vinyl group-containing linear organopolysiloxane (A1) contains a first vinyl group having a vinyl group content of 2 or more vinyl groups in the molecule and not more than 0.4 mol%. It contains a 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%. Preferably there is. As raw rubber, which is a raw material of silicone rubber, a first vinyl group-containing linear organopolysiloxane (A1-1) having a general vinyl group content and a second vinyl group-containing direct polymer having a high vinyl group content By combining with the chain organopolysiloxane (A1-2), the vinyl groups can be unevenly distributed, and the crosslink density can be more effectively formed in the crosslinked network of the silicone rubber. As a result, the tear strength of the silicone rubber can be increased more effectively.

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

  The first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol%. The second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol%.

  Further, when the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2) are combined and blended, (A1-1) The ratio of (A1-2) to (A1-2) is not particularly limited. For example, the weight ratio of (A1-1) :( A1-2) is preferably 50:50 to 95: 5, and 80:20 to 90: 10 is more preferable.

  Each of the first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may be used alone or in combination of two or more. Good.

  The vinyl group-containing organopolysiloxane (A) may include a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

<< organohydrogenpolysiloxane (B) >>
The silicone rubber-based curable composition of the present embodiment can contain an organohydrogenpolysiloxane (B).
The organohydrogenpolysiloxane (B) is classified into a linear organohydrogenpolysiloxane (B1) having a linear structure and a branched organohydrogenpolysiloxane (B2) having a branched structure. Either or both can be included.

  The straight-chain organohydrogenpolysiloxane (B1) has a straight-chain structure and a structure in which hydrogen is directly bonded to Si (≡Si—H), and is a vinyl group-containing organopolysiloxane (A). In addition to the vinyl group, the polymer is a polymer that undergoes a hydrosilylation reaction with a vinyl group contained in a component blended in the silicone rubber-based curable composition to crosslink these components.

  The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited. For example, the weight average molecular weight is preferably 20000 or less, and more preferably 1000 or more and 10,000 or less.

  In addition, the weight average molecular weight of linear organohydrogenpolysiloxane (B1) can be measured by polystyrene conversion in GPC (gel permeation chromatography) which used chloroform as a developing solvent, for example.

  Moreover, it is preferable that the linear organohydrogenpolysiloxane (B1) usually has no vinyl group. Thereby, it can prevent exactly that a crosslinking reaction advances in the molecule | numerator of linear organohydrogenpolysiloxane (B1).

  As the linear organohydrogenpolysiloxane (B1) as described above, for example, those having a structure represented by the following formula (2) are preferably used.

In formula (2), R ⁴ represents a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, a hydrocarbon group combining these, or a hydride group. As a C1-C10 alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned, for example, Among these, a methyl group is preferable. As a C1-C10 alkenyl group, a vinyl group, an allyl group, a butenyl group etc. are mentioned, for example. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

R ⁵ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, a hydrocarbon group combining these, or a hydride group. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among them, a methyl group is preferable. As a C1-C10 alkenyl group, a vinyl group, an allyl group, a butenyl group etc. are mentioned, for example. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

In the formula (2), the plurality of R ⁴ are independent from each other and may be different from each other or the same. The same is true for R ^5. However, at least two of the plurality of R ⁴ and R ⁵ are hydride groups.

R ⁶ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group obtained by combining these. As a C1-C8 alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned, for example, Among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. The plurality of R ⁶ are independent from each other and may be different from each other or the same.

In addition, as a substituent of R < ⁴ >, R < ⁵ >, R < ⁶ > in Formula (2), a methyl group, a vinyl group etc. are mentioned, for example, and a methyl group is preferable from a viewpoint of preventing the crosslinking reaction in a molecule | numerator.

  Further, m and n are the number of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by the formula (2), m is an integer of 2 to 150, and n is an integer of 2 to 150. It is. Preferably, m is an integer of 2 to 100, and n is an integer of 2 to 100.

  In addition, linear organohydrogenpolysiloxane (B1) may be used individually by 1 type, and may be used in combination of 2 or more type.

  Since the branched organohydrogenpolysiloxane (B2) has a branched structure, it forms a region having a high crosslinking density and is a component that greatly contributes to the formation of a dense structure having a crosslinking density in the system of silicone rubber. Further, similar to the above-mentioned linear organohydrogenpolysiloxane (B1), it has a structure in which hydrogen is directly bonded to Si (≡Si—H), and in addition to the vinyl group of the vinyl group-containing organopolysiloxane (A), silicone It is a polymer that undergoes a hydrosilylation reaction with the vinyl group of the components blended in the rubber-based curable composition to crosslink these components.

  The specific gravity of the branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

  Furthermore, it is preferable that the branched organohydrogenpolysiloxane (B2) usually has no vinyl group. Thereby, it can prevent exactly that a crosslinking reaction advances in the molecule | numerator of branched organohydrogenpolysiloxane (B2).

  Further, as the branched organohydrogenpolysiloxane (B2), those represented by the following average composition formula (c) are preferable.

Average composition formula (c)
(H _a (R ⁷ ) _3-a SiO _1/2 ) _m (SiO _4/2 ) _n
(In the formula (c), R ⁷ is a monovalent organic group, a is an integer in the range of 1 to 3, m is the number of H _a (R ⁷ ) _3-a SiO _1/2 units, and n is SiO _{4 / 2} units)

In the formula (c), R ⁷ is a monovalent organic group, preferably a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group, or a hydrocarbon group obtained by combining these. As a C1-C10 alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned, for example, Among these, a methyl group is preferable. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

  In the 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.

In the formula (c), m is the number of H _a (R ⁷ ) _3-a SiO _1/2 units, and n is the number of SiO _4/2 units.

  The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) differs from the branched organohydrogenpolysiloxane (B2) in that the structure is linear or branched. The number of alkyl groups R to be bonded (R / Si) is 1.8 to 2.1 for linear organohydrogenpolysiloxane (B1), and 0.8 to 1 for branched organohydrogenpolysiloxane (B2). .7 range.

  Since the branched organohydrogenpolysiloxane (B2) has a branched structure, for example, the amount of the residue when heated to 1000 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere is 5% or more. It becomes. On the other hand, since the linear organohydrogenpolysiloxane (B1) is linear, the amount of residue after heating under the above conditions is almost zero.

  Specific examples of the branched organohydrogenpolysiloxane (B2) include those having a structure represented by the following formula (3).

In Formula (3), R ⁷ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, a hydrocarbon group obtained by combining these, or a hydrogen atom. As a C1-C8 alkyl group, a methyl group, an ethyl group, a propyl group etc. are mentioned, for example, Among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. Examples of the substituent for R ⁷ include a methyl group.

In formula (3), a plurality of R ⁷ are independent from each other and may be different from each other or the same.

  In Formula (3), “—O—Si≡” represents that Si has a branched structure spreading in three dimensions.

  In addition, a branched organohydrogenpolysiloxane (B2) may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2), the amount of hydrogen atoms (hydride groups) directly bonded to Si is not particularly limited. However, in the silicone rubber-based curable composition, the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolypolyol with respect to 1 mol of the vinyl group in the vinyl group-containing linear organopolysiloxane (A1). The amount of the total amount of hydride groups of siloxane (B2) is preferably 0.5 to 5 mol, and more preferably 1 to 3.5 mol. This ensures the formation of a crosslinked network between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organopolysiloxane (A1). Can be made.

<< Silica particles (C) >>
The silicone rubber-based curable composition of the present embodiment can contain silica particles (C).

  Although it does not specifically limit as a silica particle (C), For example, fumed silica, baked silica, precipitated silica, etc. are used. These may be used alone or in combination of two or more.

Silica particles (C) are, for example, it is preferable that the specific surface area by the BET method, for example, 50 to 400 m ² / g, and more preferably 100 to 400 m ² / g. Further, the average primary particle diameter of the silica particles (C) is preferably, for example, 1 to 100 nm, and more preferably about 5 to 20 nm.

  By using the silica particles (C) within the range of the specific surface area and the average particle diameter, it is possible to improve the hardness and mechanical strength of the formed silicone rubber, particularly the tensile strength.

<< Silane coupling agent (D) >>
The silicone rubber-based curable composition of the present embodiment can contain a silane coupling agent (D).
The silane coupling agent (D) can have a hydrolyzable group. The surface modification of the silica particles (C) can be carried out by hydrolyzing the hydrolyzable groups with water to form hydroxyl groups, which undergo a dehydration condensation reaction with the hydroxyl groups on the surface of the silica particles (C).

  Moreover, this silane coupling agent (D) can contain the silane coupling agent which has a hydrophobic group. Thereby, since this hydrophobic group is imparted to the surface of the silica particles (C), the cohesive force of the silica particles (C) is reduced in the silicone rubber-based curable composition and thus in the silicone rubber (hydrogen due to silanol groups). As a result, the dispersibility of the silica particles in the silicone rubber-based curable composition is estimated to be improved. Thereby, the interface of a silica particle and a rubber matrix increases, and the reinforcement effect of a silica particle increases. Furthermore, when the rubber matrix is deformed, it is presumed that the sliding property of the silica particles in the matrix is improved. And the mechanical strength (for example, tensile strength, tear strength, etc.) of the silicone rubber by a silica particle (C) improves by the improvement of the dispersibility of silica particle (C), and the improvement of slipperiness.

  Furthermore, the silane coupling agent (D) can contain a silane coupling agent having a vinyl group. Thereby, a vinyl group is introduce | transduced into the surface of a silica particle (C). Therefore, when the silicone rubber-based curable composition is cured, that is, the vinyl group of the vinyl group-containing organopolysiloxane (A) and the hydride group of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction. When the network (crosslinked structure) is formed, the vinyl group of the silica particles (C) is also involved in the hydrosilylation reaction with the hydride group of the organohydrogenpolysiloxane (B). Silica particles (C) are also taken in. Thereby, low hardness and high modulus of the formed silicone rubber can be achieved.

  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.

  As a silane coupling agent (D), what is represented by following formula (4) is mentioned, for example.

_{Y n -Si- (X) 4-} n ··· (4)
In said formula (4), n represents the integer of 1-3. Y represents a functional group of any one having a hydrophobic group, a hydrophilic group or a vinyl group. 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. It is a hydrophobic group. X represents a hydrolyzable group.

  The hydrophobic group is an alkyl group having 1 to 6 carbon atoms, an aryl group, or a hydrocarbon group that is a combination thereof, and examples thereof include a methyl group, an ethyl group, a propyl group, and a phenyl group. A methyl group is preferred.

Examples of the hydrophilic group include a hydroxyl group, a sulfonic acid group, a carboxyl group, and a carbonyl group. Among these, a hydroxyl group is particularly preferable. The hydrophilic group may be included as a functional group, but is preferably not included from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

Furthermore, examples of the hydrolyzable group include an alkoxy group such as a methoxy group and an ethoxy group, a chloro group, and a silazane group. Among them, a silazane group is preferable because of its high reactivity with the silica particles (C). Incidentally, those having a silazane group as hydrolyzable groups, the characteristics of its structure the formula (4) in the structure of (Y _n -Si-) comes to have two.

  Specific examples of the silane coupling agent (D) represented by the above formula (4) include, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltrimethoxysilane, having a hydrophobic group as a functional group. Alkoxysilanes such as ethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane; methyltrichlorosilane Chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; hexamethyldisilazane, and methacryloxypropyltriethoxysilane having a vinyl group as a functional group. , Alkoxysilanes such as methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane; vinyltrichlorosilane, vinylmethyl Chlorosilanes such as dichlorosilane; divinyltetramethyldisilazane can be mentioned. Among them, considering the above description, hexamethyldisilazane having a hydrophobic group and divinyltetramethyl having a vinyl group are particularly preferable. Disilazane is preferred.

<< Platinum or platinum compound (E) >>
The silicone rubber-based curable composition of the present embodiment can contain platinum or a platinum compound (E).
Platinum or a platinum compound (E) is a catalyst component that acts as a catalyst during curing. The amount of platinum or platinum compound (E) added is a catalytic amount.

  As the platinum or platinum compound (E), known ones can be used, for example, platinum black, platinum supported on silica or carbon black, chloroplatinic acid or an alcohol solution of chloroplatinic acid, chloride Examples thereof include complex salts of platinum acid and olefins, complex salts of chloroplatinic acid and vinyl siloxane, and the like.

  In addition, platinum or a platinum compound (E) may be used individually by 1 type, and may be used in combination of 2 or more type.

<< Water (F) >>
Moreover, the silicone rubber-based curable composition of the present embodiment may contain water (F) in addition to the components (A) to (E).

  Water (F) is a component that functions as a dispersion medium for dispersing each component contained in the silicone rubber-based curable composition and contributes to the reaction between the silica particles (C) and the silane coupling agent (D). . Therefore, in the silicone rubber, the silica particles (C) and the silane coupling agent (D) can be more reliably connected to each other, and uniform characteristics can be exhibited as a whole.

  Furthermore, the silicone rubber-based curable composition of this embodiment may contain a known additive component blended in the silicone rubber-based curable composition in addition to the components (A) to (F). Examples thereof include diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, and mica. In addition, dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, thermal conductivity improvers, and the like can be appropriately blended.

  In the silicone rubber-based curable composition, the content ratio of each component is not particularly limited, but is set as follows, for example.

  In the present embodiment, the upper limit of the content of the silica particles (C) may be, for example, 60 parts by weight or less, preferably 50 parts by weight with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). Or less, more preferably 35 parts by weight or less. Thereby, balance of mechanical strength, such as hardness and tensile strength, can be aimed at. Moreover, although the lower limit of content of a silica particle (C) is not specifically limited with respect to 100 weight part of total amounts of vinyl group containing organopolysiloxane (A), For example, 20 weight part or more may be sufficient.

The silane coupling agent (D) is preferably contained, for example, in a proportion of 5 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the vinyl group-containing organopolysiloxane (A). More preferably, it is contained in a proportion of 5 to 40 parts by weight.
Thereby, the dispersibility in the silicone rubber-type curable composition of a silica particle (C) can be improved reliably.

  Specifically, the content of the organohydrogenpolysiloxane (B) is, for example, relative to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A) and the silica particles (C) and the silane coupling agent (D). The content is preferably 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. There exists a possibility that more effective hardening reaction can be performed because content of (B) exists in the said range.

  The content of platinum or the platinum compound (E) means a catalytic amount and can be appropriately set. Specifically, the vinyl group-containing organopolysiloxane (A), silica particles (C), silane coupling agent ( The amount of platinum group metal in this component is 0.01 to 1000 ppm by weight, and preferably 0.1 to 500 ppm with respect to the total amount of D). By making content of platinum or a platinum compound (E) more than the said lower limit, the silicone rubber composition obtained can fully be hardened. By making content of platinum or a platinum compound (E) below the said upper limit, the cure rate of the silicone rubber composition obtained can be improved.

  Furthermore, when it contains water (F), the content can be set as appropriate. Specifically, for example, 10 to 100 parts by weight with respect to 100 parts by weight of the silane coupling agent (D). Is preferable, and the range of 30 to 70 parts by weight is more preferable. Thereby, reaction with a silane coupling agent (D) and a silica particle (C) can be advanced more reliably.

<Method for producing silicone rubber>
Next, the manufacturing method of the silicone rubber of this embodiment is demonstrated.
As a method for producing the silicone rubber of the present embodiment, a silicone rubber can be obtained by preparing a silicone rubber-based curable composition and curing the silicone rubber-based curable composition.
Details will be described below.

  First, each component of the silicone rubber-based curable composition is uniformly mixed by an arbitrary kneading apparatus to prepare a silicone rubber-based curable composition.

[1] For example, a predetermined amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D) are weighed, and then kneaded by an arbitrary kneading apparatus. A kneaded product containing these components (A), (C), and (D) is obtained.

  The kneaded product is preferably obtained by kneading the vinyl group-containing organopolysiloxane (A) and the silane coupling agent (D) in advance, and then kneading (mixing) the silica particles (C). Thereby, the dispersibility of the silica particles (C) in the vinyl group-containing organopolysiloxane (A) is further improved.

  Moreover, when obtaining this kneaded material, you may make it add water (F) to the kneaded material of each component (A), (C), and (D) as needed. Thereby, reaction with a silane coupling agent (D) and a silica particle (C) can be advanced more reliably.

  Furthermore, kneading of the components (A), (C), and (D) is preferably performed through a first step of heating at the first temperature and a second step of heating at the second temperature. Thereby, in the first step, the surface of the silica particles (C) can be surface-treated with the coupling agent (D), and in the second step, the silica particles (C) and the coupling agent (D) By-products generated by the reaction can be reliably removed from the kneaded product. Thereafter, if necessary, the component (A) may be added to the obtained kneaded product and further kneaded. Thereby, the familiarity of the components of the kneaded product can be improved.

  For example, the first temperature is preferably about 40 to 120 ° C, and more preferably about 60 to 90 ° C. The second temperature is preferably about 130 to 210 ° C, for example, and more preferably about 160 to 180 ° C.

  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.

  Furthermore, the time of the first step is preferably, for example, about 0.3 to 1.5 hours, and more preferably about 0.5 to 1.2 hours. The time for the second step is, for example, preferably about 0.7 to 3.0 hours, and more preferably about 1.0 to 2.0 hours.

  By setting the first step and the second step as described above, the effect can be obtained more remarkably.

[2] Next, a predetermined amount of organohydrogenpolysiloxane (B) and platinum or platinum compound (E) are weighed, and then kneaded product prepared in the above step [1] using an arbitrary kneading apparatus. In addition, the silicone rubber-based curable composition is obtained by kneading the components (B) and (E). The obtained silicone rubber-based curable composition may be a paste containing a solvent.

  When kneading each of the components (B) and (E), the kneaded material prepared in advance in the step [1] and the organohydrogenpolysiloxane (B) were prepared in the step [1]. It is preferable to knead the kneaded material and platinum or the platinum compound (E), and then knead each kneaded material. As a result, the components (A) to (E) are surely contained in the silicone rubber-based curable composition without causing a reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B). Can be dispersed.

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

  Furthermore, the kneading time is preferably, for example, about 5 minutes to 1 hour, and more preferably about 10 to 40 minutes.

  In the step [1] and the step [2], by setting the temperature within the above range, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) is more accurately performed. Can be prevented or suppressed. Moreover, in said process [1] and said process [2], by making kneading time into the said range, each component (A)-(E) can be more reliably disperse | distributed in a silicone rubber-type curable composition. Can do.

  The kneading apparatus used in each of the steps [1] and [2] is not particularly limited, and for example, a kneader, two rolls, a Banbury mixer (continuous kneader), a pressure kneader, or the like can be used.

  In this step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded product. Thereby, even if the temperature of the kneaded product is set to a relatively high temperature, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) is more accurately prevented or suppressed. be able to.

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

In this embodiment, the curing process of the silicone rubber-based curable resin composition is, for example, heated (primary curing) at 100 to 250 ° C. for 1 to 30 minutes, and then post-baked (secondary) at 200 ° C. for 1 to 4 hours. Curing).
By passing through the above processes, the silicone rubber of this embodiment is obtained.

  As a result of investigation by the present inventors, the following findings were obtained. In general, increasing the amount of filler in the silicone rubber can increase the hardness and tensile strength, but it has been found that the tear strength and elongation at break decrease.

  Therefore, as a result of diligent investigation, by appropriately selecting a resin composition such as vinyl group-containing organopolysiloxane (A), it is possible to control the cross-link density and the uneven distribution of the cross-linked structure, and to achieve high hardness and high tensile strength in a wide range of strain. It has been found that the tear strength and elongation at break of silicone rubber can be controlled while realizing the above. It was also found that the tensile strength of silicone rubber can be increased. Although the detailed mechanism is not clear, the combined use of the high vinyl group-containing organopolysiloxane and the low vinyl group-containing organopolysiloxane can control the uneven distribution of the cross-linked structure. It is considered that high elongation at break can be realized. Thus, the fracture energy of the silicone rubber can be increased by increasing the tear strength while maintaining other physical properties.

  In the present embodiment, for example, by appropriately selecting the type and amount of each component contained in the silicone rubber-based curable composition, the method for preparing the silicone rubber-based curable composition, the method for producing the silicone rubber, and the like, The tensile stress, elongation at break, tensile strength, tear strength, and hardness can be controlled. Among these, for example, a combination of a low vinyl group-containing linear organopolysiloxane (A1-1) and a high vinyl group-containing linear organopolysiloxane (A1-2), a vinyl having a vinyl group at the terminal Controlling uneven distribution of resin crosslink density and crosslink structure by using group-containing organopolysiloxane (A), addition timing and ratio of vinyl group-containing organopolysiloxane (A), silica particles (C) More reliable reaction between the silane coupling agent (D) and the silica particles (C) such as surface modification with the silane coupling agent (D) of the silica particles (C) and addition of water. And the like are included as elements for bringing the tensile stress, elongation at break, tensile strength, and tear strength into desired numerical ranges.

  In this embodiment, when measuring the tensile stress, elongation at break, tensile strength, and tear strength in the silicone rubber-based curable composition, a cured product of the silicone rubber-based curable composition is used as a heating object and a measurement object. be able to. As this cured product, for example, a silicone rubber-based curable composition is pressed at 160 ° C. and 10 MPa for 20 minutes to be molded into a sheet having a thickness of 1 mm, followed by primary curing, and subsequently at 200 ° C. for 4 hours. A sheet-like silicone rubber (cured product of a silicone rubber-based curable composition) obtained by heating and secondary curing may be used.

  As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and various structures other than the above are also employable.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail with reference to an Example, this invention is not limited to description of these Examples at all.

The raw material components used in Examples and Comparative Examples shown in Table 1 are shown below.
(Vinyl group-containing organopolysiloxane (A))
Low vinyl group-containing linear organopolysiloxane (A1-1): terminal vinyl group-containing dimethylpolysiloxane synthesized by Synthesis Scheme 1 (in the structure represented by formula (1-1), only R ¹ (terminal) is a vinyl group Is a structure)
High vinyl group-containing linear organopolysiloxane (A1-2): vinyl group-containing dimethylpolysiloxane synthesized by Synthesis Scheme 2 (in the structure represented by formula (1-1), R ¹ and R ² are vinyl groups) Construction)

(Organohydrogenpolysiloxane (B))
Two types of organohydrogenpolysiloxanes (Momentive, Inc .: “TC-25D”,
(Shin-Etsu Chemical Co., Ltd .: “C-25B”)

(Silica particles (C))
Silica particles (C): silica fine particles (particle size 7 nm, specific surface area 300 m ² / g), manufactured by Nippon Aerosil Co., Ltd., “AEROSIL 300”

(Silane coupling agent (D))
Silane coupling agent (D-1): Hexamethyldisilazane (HMDZ), manufactured by Gelest Co., Ltd., “HEXAMETHY LDISILAZANE (SIH6110.1)”
Silane coupling agent (D-2): Divinyltetramethyldisilazane, manufactured by Gelest, “1,3-DIVINYLTETRAMETHYLDISILAZANE (SID4612.0)”

(Platinum or platinum compound (E))
Two types of platinum or platinum compounds (Momentive: “TC-25A”, Shin-Etsu Chemical: “C-25A”)

(Synthesis of vinyl group-containing organopolysiloxane (A))
[Synthesis Scheme 1: Synthesis of low vinyl group-containing linear organopolysiloxane (A1-1)]
A low vinyl group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (7).
That is, Ar gas-substituted 300 mL separable flask having a cooling tube and a stirring blade was charged with 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium siliconate, heated, and heated at 120 ° C. for 30 minutes. Stir. At this time, an increase in viscosity was confirmed.
Thereafter, the temperature was 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 the mixture was further stirred at 155 ° C. for 4 hours.
Further, after 4 hours, the mixture was diluted with 250 mL of toluene and then washed with water three times. The washed organic layer was washed several times with 1.5 L of methanol, and purified by reprecipitation 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 ⁵ , Mw = 4, 8 × 10 ^5). ). Moreover, vinyl group content computed by H-NMR spectrum measurement was 0.04 mol%.

[Synthesis Scheme 2: Synthesis of High Vinyl Group-Containing Linear Organopolysiloxane (A1-2)]
In the synthesis step (A1-1), in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane, 2,4,6,8-tetramethyl 2,4,6,8-tetravinylcyclotetrasiloxane Except that 86 g (2.5 mmol) was used, the high vinyl group-containing linear organopolysiloxane (A1-2) was converted into the same as in the synthesis step of (A1-1) by the following formula. Synthesized. (Mn = 2, 3 × 10 ⁵ , Mw = 5, 0 × 10 ⁵ ). The vinyl group content calculated by H-NMR spectrum measurement was 0.93 mol%.

(Example 1: Preparation of silicone rubber-based curable composition)
In Example 1, 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 kneaded in advance at the ratio shown in Table 1 below, and then silica particles ( C) was added and further kneaded to obtain a kneaded product (silicone rubber compound).
Here, the kneading after the addition of the silica particles (C) includes the first step of kneading for 1 hour under the condition of 60 to 90 ° C. in a nitrogen atmosphere for the coupling reaction, and the removal of the by-product (ammonia). Therefore, the second step of kneading for 2 hours under the condition of 160 to 180 ° C. in a reduced-pressure atmosphere is performed, and then cooled, and the remaining 10% of the vinyl group-containing organopolysiloxane (A) is added twice. Add in portions and knead for 20 minutes.
Subsequently, to 100 parts by weight of the obtained kneaded material (silicone rubber compound), 4.53 parts by weight of organohydrogenpolysiloxane (TC-25D) and 0.5 parts by weight of platinum or platinum compound (TC-25A) were added. And kneading with a roll to obtain a silicone rubber-based curable composition.

(Example 2: Preparation of silicone rubber-based curable composition)
In Example 2, Shin-Etsu Chemical Co., Ltd. (product number: KE-561-U) was used as the silicone rubber compound.
Subsequently, to 100 parts by weight of the silicone rubber compound, 2 parts by weight of organohydrogenpolysiloxane (C-25B) and 0.5 parts by weight of platinum or platinum compound (C-25A) are added and kneaded with a roll. A silicone rubber-based curable composition was obtained.

(Example 3: Preparation of 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 90% vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) is pre-kneaded in the proportions shown in Table 1, and then silica particles (C) are mixed into the mixture. Was further kneaded to obtain a kneaded product (silicone rubber compound).
Here, the kneading after the addition of the silica particles (C) was performed in the same manner as in Example 1.
Subsequently, 3.77 parts by weight of organohydrogenpolysiloxane (TC-25D) and 0.5 parts by weight of platinum or a platinum compound (TC-25A) were added to 100 parts by weight of the obtained kneaded material (silicone rubber compound). The mixture was kneaded with a roll to obtain a silicone rubber curable composition of Example 3.

(Example 4: Preparation of 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 90% vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) is pre-kneaded in the proportions shown in Table 1, and then silica particles (C) are mixed into the mixture. Was further kneaded to obtain a kneaded product (silicone rubber compound).
Here, the kneading after the addition of the silica particles (C) was performed in the same manner as in Example 1.
Subsequently, 2.26 parts by weight of organohydrogenpolysiloxane (TC-25D) and 0.5 part by weight of platinum or a platinum compound (TC-25A) were added to 100 parts by weight of the obtained kneaded material (silicone rubber compound). The mixture was kneaded with a roll to obtain a silicone rubber curable composition of Example 4.

(Production of silicone rubber)
In Examples 1 to 4, the obtained silicone rubber-based curable composition was pressed at 160 ° C. and 10 MPa for 20 minutes to form a sheet having a thickness of 1 mm and primary cured. Subsequently, it was heated at 200 ° C. for 4 hours and secondarily cured. Thus, a sheet-like silicone rubber (a cured product of a silicone rubber-based curable composition) was obtained. The following evaluation was performed on the obtained sheet-like silicone rubber (sheet-like elastomer). The evaluation results are shown in Tables 2-4. Tensile stress, elongation at break, and tensile strength were measured using three samples, and three average values were used as measured values. Moreover, about tear strength, it carried out with five samples and made five average values into the measured value. The average values are shown in Tables 2 to 4, respectively.

[Comparative Example 1]
Using natural rubber sheets (hardness 60, thickness 1 mm, width 500 mm x length 500 mm, ASONE product code 2-9289-02) purchased from ASONE CORPORATION, test specimens described in each characteristic evaluation were prepared. The following evaluation was performed. About the evaluation result, it carried out similarly to the sample number described in preparation of silicone rubber, and the frequency | count of evaluation.
[Comparative Example 2]
Using a sheet of chloroprene rubber (hardness 60, thickness 1 mm, width 500 mm × length 500 mm, ASONE product code 2-9293-02) purchased from ASONE Corporation, a test piece described in each characteristic evaluation was prepared. The following evaluation was performed. About the evaluation result, it carried out similarly to the sample number described in preparation of silicone rubber, and the frequency | count of evaluation.
[Comparative Example 3]
Polyester urethane sheet (hardness 70, thickness 1mm, width 500mm x length 500mm, rubber thread product code 10004-0001-2-0) purchased from Fuso Rubber Industry Co., Ltd. is used and described in each characteristic evaluation The prepared test pieces were prepared and evaluated as follows. About the evaluation result, it carried out similarly to the sample number described in preparation of silicone rubber, and the frequency | count of evaluation.
[Comparative Example 4]
Using the ethylene propylene rubber sheet (hardness 65, thickness 1mm, width 500mm x length 500mm, ASONE product code 2-9301-02) purchased from ASONE Corporation, the test pieces described in each characteristic evaluation were prepared. Then, the following evaluation was performed. About the evaluation result, it carried out similarly to the sample number described in preparation of silicone rubber, and the frequency | count of evaluation.
[Comparative Example 5]
Using a nitrile rubber sheet (hardness 60, thickness 1 mm, width 300 mm x length 300 mm, ASONE product code 2-9305-01) purchased from ASONE Corporation, a test piece described in each characteristic evaluation was prepared. The following evaluation was performed. About the evaluation result, it carried out similarly to the sample number described in preparation of silicone rubber, and the frequency | count of evaluation.

“-” In Tables 2 to 4 will be described. “-” Indicates that the elastomer was broken by the heat treatment and the measurement result was not obtained. For example, in Table 4, because the elastomer of Comparative Example 3 was melted by heating at 200 ° C., the elongation at break BE3, tensile stress M3 ₁₀₀ , tensile strength S3, and tear strength TS3 could not be measured. Further, with respect to the elastomers of Comparative Examples 1, 2, 4, and 5, the tensile stress M3 ₁₀₀ could not be measured because the elastomer was broken when it was stretched 100% at 200 after being held at 200 ° C. for 30 minutes.

(Hardness: Durometer hardness A)
Six sheets of the obtained sheet-like silicone rubber of each example and the sheet-like elastomer of each comparative example having a thickness of 1 mm were laminated to prepare a 6 mm test piece. The type A durometer hardness was measured on the obtained test piece at a room temperature of 25 ° C. in accordance with JIS K6253 (1997). The results are shown in Table 5.

<Elongation at break>
Using the obtained sheet-like silicone rubber of each example and the sheet-like elastomer of each comparative example having a thickness of 1 mm, a dumbbell-shaped No. 3 test piece was prepared according to JIS K6251 (2004), The elongation at break of the obtained dumbbell-shaped No. 3 test piece was measured. The elongation at break was calculated as [movement distance between chucks (mm)] ÷ [distance between initial chucks (60 mm)] × 100. The unit is%.
(Measurement conditions of elongation at break)
Breaking elongation BE0: Breaking elongation measured in accordance with JIS K6251 (2004) of dumbbell-shaped No. 3 test piece at room temperature of 25 ° C. without further heat treatment on dumbbell-shaped No. 3 test piece And
Breaking elongation BE1: Breaking elongation measured according to JIS K6251 (2004) of a dumbbell-shaped No. 3 test piece as it is at 100 ° C. after being held at 100 ° C. for 30 minutes against a dumbbell-shaped No. 3 test piece And
Breaking elongation BE2: Breaking elongation measured according to JIS K6251 (2004) of dumbbell-shaped No. 3 test piece as it is at 150 ° C. after holding for 30 minutes at 150 ° C. with respect to the dumbbell-shaped No. 3 test piece And
Breaking elongation BE3: Breaking elongation measured according to JIS K6251 (2004) of dumbbell-shaped No. 3 test piece as it is at 200 ° C. after being held at 200 ° C. for 30 minutes with respect to the dumbbell-shaped No. 3 test piece And

<Tensile stress>
Using the obtained sheet-like silicone rubber of each example and the sheet-like elastomer of each comparative example having a thickness of 1 mm, a dumbbell-shaped No. 3 test piece was prepared according to JIS K6251 (2004), the resulting No. 3 dumbbell test pieces were measured stress M ₁₀₀ tensile during the 100% elongation at room temperature 25 ° C.. The unit is MPa.
(Measurement conditions of tensile stress)
Tensile stress M ₁₀₀ 0: The dumbbell-shaped No. 3 test piece is regarded as the tensile stress at the time of 100% elongation of the dumbbell-shaped No. 3 test piece at 25 ° C. without further heat treatment.
Tensile stress M ₁₀₀ 1: After holding at 100 ° C. for 30 minutes with respect to the dumbbell-shaped No. 3 test piece, the tensile stress at 100 ° C. when the dumbbell-shaped No. 3 test piece is 100% stretched is used as it is.
Tensile stress _{M 100} 2: relative No. 3 dumbbell test piece, 0.99 ° C., after 30 minutes holding, in the ready-0.99 ° C., and the tensile stress at 100% elongation of the No. 3 dumbbell test piece.
Tensile stress M ₁₀₀ 3: It is set as the tensile stress at the time of 100% expansion | extension of the said dumbbell-shaped 3 type test piece in 200 degreeC after hold | maintaining with respect to a dumbbell-shaped 3 type test piece at 200 degreeC for 30 minutes.

<Tensile strength>
Using the obtained sheet-like silicone rubber of each example and the sheet-like elastomer of each comparative example having a thickness of 1 mm, a dumbbell-shaped No. 3 test piece was prepared according to JIS K6251 (2004), The tensile strength of the obtained dumbbell-shaped No. 3 test piece was measured. The unit is MPa.
(Measurement conditions of tensile strength)
Tensile strength S0: Tensile strength measured according to JIS K6251 (2004) of dumbbell-shaped No. 3 test piece at room temperature of 25 ° C. without further heat treatment on dumbbell-shaped No. 3 test piece And
Tensile strength S1: Tensile strength measured according to JIS K6251 (2004) of dumbbell-shaped No. 3 test piece as it is at 100 ° C. after being held at 100 ° C. for 30 minutes with respect to the dumbbell-shaped No. 3 test piece And
Tensile strength S2: Tensile strength measured according to JIS K6251 (2004) of dumbbell-shaped No. 3 test piece at 150 ° C. after holding at 150 ° C. for 30 minutes against dumbbell-shaped No. 3 test piece And
Tensile strength S3: Tensile strength measured according to JIS K6251 (2004) of dumbbell-shaped No. 3 test piece at 200 ° C. as it is after holding for 30 minutes at 200 ° C. with respect to dumbbell-shaped No. 3 test piece And

<Tear strength>
Using the obtained sheet-like silicone rubber of each example and the sheet-like elastomer of each comparative example having a thickness of 1 mm, a crescent-shaped test piece was prepared and obtained in accordance with JIS K6252 (2001). The tear strength of the crescent test piece was measured. The unit is N / mm.
(Tearning strength measurement conditions)
Tear strength TS0: The crescent-type test piece is not subjected to further heat treatment, and is the tear strength measured at room temperature of 25 ° C. according to JIS K6252 (2001) of the crescent-type test piece.
Tear strength TS1: It is made into the tear strength measured based on JISK6252 (2001) of a crescent type test piece in 100 degreeC as it is after holding at 100 degreeC for 30 minutes with respect to a crescent type test piece.
Tear strength TS2: It is set as the tear strength measured according to JIS K6252 (2001) of the elastomer at 150 ° C. after being held at 150 ° C. for 30 minutes.
Tear strength TS3: It is set as the tear strength measured according to JIS K6252 (2001) of the said elastomer at 200 degreeC after hold | maintaining with respect to the said elastomer at 200 degreeC for 30 minutes.

<Heat resistance and durability test>
Using the obtained sheet-like silicone rubber of each example and the sheet-like elastomer of each comparative example having a thickness of 1 mm, a dumbbell-shaped No. 3 test piece was prepared according to JIS K6251 (2004), The obtained dumbbell-shaped No. 3 test piece was evaluated for the presence or absence of breakage when it was stretched 100% after being held at 200 ° C. for 30 minutes.

The thermoplastic elastomers of Comparative Examples 1, 2, 4, and 5 were found to have reduced heat resistance and durability because breakage occurred in the above heat resistance and durability test. Further, it was found that the thermosetting elastomer (polyurethane) of Comparative Example 3 was deteriorated in heat resistance and durability because the elastomer was melted by heating at 200 ° C.
On the other hand, since the thermosetting elastomer (silicone rubber) of each Example does not break in the above heat resistance / durability test, the heat curable elastomer (silicone rubber) has higher heat resistance / durability than the elastomers of Comparative Examples 1-5. I found it excellent.

Claims (9)

An elastomer having ((tensile strength S3−tensile strength S0) / tensile strength S0) × 100 measured under the following conditions is −80% or more.
(conditions)
Tensile strength S0: The elastomer is subjected to a tensile strength measured in accordance with JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Tensile strength S3: The tensile strength measured at 200 ° C. according to JIS K6251 (2004) of the elastomer after holding at 200 ° C. for 30 minutes. The elastomer according to claim 1,
An elastomer having ((tensile strength S1−tensile strength S0) / tensile strength S0) × 100 measured under the following conditions is −50.0% or more.
(conditions)
Tensile strength S0: The elastomer is subjected to a tensile strength measured in accordance with JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Tensile strength S1: It is set as the tensile strength measured according to JIS K6251 (2004) of the elastomer at 100 ° C. after being held at 100 ° C. for 30 minutes. The elastomer according to claim 1 or 2,
An elastomer having ((breaking elongation BE3−breaking elongation BE0) / breaking elongation BE0) × 100 measured at the following conditions is −85.5% or more.
(conditions)
Elongation at break BE0: The elastomer is subjected to the elongation at break measured according to JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Breaking elongation BE3: The elongation at break of the elastomer is measured at 200 ° C. for 30 minutes and then measured at 200 ° C. according to JIS K6251 (2004). The elastomer according to any one of claims 1 to 3,
The elastomer whose ((breaking elongation BE1-breaking elongation BE0) / breaking elongation BE0) * 100 measured on the following conditions is more than -50%.
(conditions)
Elongation at break BE0: The elastomer is subjected to the elongation at break measured according to JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Elongation at break BE1: It is set as the elongation at break measured according to JIS K6251 (2004) of the elastomer at 100 ° C. after being held at 100 ° C. for 30 minutes. The elastomer according to any one of claims 1 to 4,
An elastomer having ((tensile strength S2−tensile strength S0) / tensile strength S0) × 100 measured under the following conditions is −60% or more.
(conditions)
Tensile strength S0: The elastomer is subjected to a tensile strength measured in accordance with JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Tensile strength S2: The tensile strength measured at 150 ° C. according to JIS K6251 (2004) of the elastomer after holding at 150 ° C. for 30 minutes. The elastomer according to any one of claims 1 to 5,
An elastomer having ((breaking elongation BE2−breaking elongation BE0) / breaking elongation BE0) × 100 measured at the following conditions is −60% or more.
(conditions)
Elongation at break BE0: The elastomer is subjected to the elongation at break measured according to JIS K6251 (2004) of the elastomer at room temperature of 25 ° C. without further heat treatment.
Elongation at break BE2: The elongation at break is measured according to JIS K6251 (2004) of the elastomer at 150 ° C. after being held at 150 ° C. for 30 minutes. The elastomer according to any one of claims 1 to 6,
An elastomer having a tear strength TS2 of 5 N / mm or more, measured under the following conditions.
(conditions)
Tear strength TS2: Tear strength measured at 150 ° C. according to JIS K6252 (2001) of the elastomer after holding at 150 ° C. for 30 minutes. The elastomer according to any one of claims 1 to 7,
An elastomer containing an inorganic filler.   A molded body comprising the elastomer according to any one of claims 1 to 8.