JP6881478B2 - Resin movable members and structures - Google Patents

Description

The present invention relates to a resin movable member and a structure.

So far, movable members that constitute moving parts of various appliances and devices have been studied. As a technique of this kind, for example, the technique described in Patent Document 1 is known. Patent Document 1 describes an exodermis tube that covers the main body of an endoscope flexible tube. The document describes that the hysteresis loss can be reduced by using a thermoplastic elastomer that does not contain an inorganic powder filler in the outer skin tube (paragraph 0016 of Patent Document 1).

Japanese Unexamined Patent Publication No. 11-86637

However, as a result of examination by the present inventor, it has been found that the tube described in Document 1 has room for improvement in terms of mechanical strength and durability against deformation. Further, even when the above tube is applied to a moving part of a medical device / device other than such a medical tube, an industrial robot, an electronic device, etc., there is room for improvement in such mechanical strength and durability. It was.

As a result of the examination by the present inventor, the following findings were obtained.
Generally, the mechanical strength can be increased by adding a reinforcing material such as an inorganic filler to the elastomer, but on the contrary, when the elastomer is deformed during use, the plastic deformation that occurs in the elastomer is large. Therefore, the hysteresis loss tends to increase.

On the other hand, the present inventor has found that by appropriately controlling the resin structure such as the crosslink density, it is possible to reduce the hysteresis loss while increasing the mechanical strength.
As a result of further examination, the tensile strength S was used as an index for evaluating the state of mechanical strength, and the hysteresis loss fluctuation ratio (ΔE2 / ΔE1) in the first and second stretching operations was used as an index for evaluating the state of hysteresis loss. ), And by adopting the product value of the tensile strength S and the hysteresis loss fluctuation ratio (ΔE2 / ΔE1) as an index, it was found that the balance between the mechanical strength and the hysteresis loss can be stably evaluated. ..
As a result of further diligent research based on such findings, the product value of the tensile strength S and the hysteresis loss fluctuation ratio (ΔE2 / ΔE1) was set to a predetermined value or more while controlling the hysteresis loss fluctuation ratio (ΔE2 / ΔE1) to be small. By doing so, it has been found that a resin movable member having excellent mechanical strength and durability during repeated deformation can be realized, and the present invention has been completed.
Further, it was found that the resin movable member obtained based on such an index is suitable for a usage environment in which it is used to repeatedly deform by following the movement of the movable part of various instruments and devices.

According to the present invention
It is a resin movable member made of silicone rubber.
The silicone rubber is a cured product of a silicone rubber-based curable composition.
The silicone rubber-based curable composition contains a vinyl group-containing organopolysiloxane (A), an organohydrogenpolysiloxane (B), and silica particles (C).
The content of the silica particles (C) is defined as X (parts by weight) with respect to 100 parts by weight of the vinyl group-containing organopolysiloxane (A), and is defined by JIS K6253 of the cured product of the silicone-based curing composition. When the durometer hardness A is Y, X / Y is 0.91 or less.
Do the following stretching procedure was repeated twice, and the hysteresis loss at the time of the first round of the decompression operations and ΔE1, the hysteresis loss at the time of the extension operation of the second and ΔE2, 2 round of hysteresis for the first time of the hysteresis loss Let H1 (%) be the fluctuation ratio of loss | ΔE2 / ΔE1 | × 100.
When the tensile strength measured in accordance with JIS K6251 (2004) is S (MPa),
H1 is 25 or less, and H1 × S is 130 or more and 400 or less.
The breaking elongation measured according to JIS K6251 (2004) is 200% or more and 1000% or less.
A resin movable member is provided.
(Extension operation)
The stretching operation is an operation in which the dumbbell test piece is stretched from a displacement amount of 0% to 500% at a room temperature of 25 ° C. and a stretching speed of 1000 mm / min, and then contracted by a displacement amount of 500% to 0%. ..

Further, according to the present invention.
A structure comprising the fat movable member is provided.

According to the present invention, a resin movable member and a structure having excellent mechanical strength and durability are provided.

It is a figure for demonstrating the extension operation.

In the resin movable member of the present embodiment, the following stretching operation is repeated 5 times, the hysteresis loss at the first stretching operation is ΔE1, and the hysteresis loss at the second stretching operation is ΔE2. Let H1 (%) be | ΔE2 / ΔE1 | × 100, which is the fluctuation ratio of the second hysteresis loss to the first hysteresis loss, and let S (MPa) be the tensile strength measured in accordance with JIS K6251 (2004). When this is done, H1 can be 25 or less, and H1 × S can be 125 or more and 400 or less.

In the present embodiment, the stretching operation means stretching the dumbbell test piece from 0% to 500% of displacement at room temperature of 25 ° C. and stretching speed of 1000 mm / min, and then from 500% to 0% of displacement by removing force. It can be an operation of contracting. This stretching operation may be performed continuously.

Further, the hysteresis loss can be the difference energy ΔE between the stretching energy (mJ) at the time of stretching and the weakening energy (mJ) at the time of returning the deformation in one stretching operation. These stretching energies and weakening energies are shown by the stress-strain curve obtained by the stretching operation, that is, the vertical axis: the load during the stretching operation (N) and the horizontal axis: the displacement amount during the stretching operation (mm). It can be calculated from the area (having the energy dimension) obtained by integration from the curve.

The present inventor uses the tensile strength S as an index for evaluating the state of mechanical strength, and the hysteresis loss fluctuation ratio H1 (| ΔE2) in the first and second stretching operations as an index for evaluating the state of hysteresis loss. It was found that the balance between mechanical strength and hysteresis loss can be stably evaluated by using the product value of tensile strength S and hysteresis loss fluctuation ratio H1 as an index after using / ΔE1 | × 100). did.
Further, the present inventor considered that the value of the first hysteresis loss ΔE1 fluctuates depending on the initial state such as hardness, and it is difficult to reduce ΔE1 itself.
Therefore, it was considered that the influence of the difference in the initial state such as hardness can be reduced by dividing the predetermined Nth hysteresis loss ΔEN by the first hysteresis loss ΔE1 in the hysteresis loss fluctuation ratio.
Based on this idea, the mechanical strength is set by setting the product value of the tensile strength S and the hysteresis loss fluctuation ratio H1 to be equal to or higher than the above lower limit value while setting the hysteresis loss fluctuation ratio H1 to be equal to or lower than the above upper limit value. Further, they have found that a resin movable member having excellent durability against deformation can be realized, and have completed the present invention.

Further, in the resin movable member of the present embodiment, the hysteresis loss at the time of the fifth extension operation is ΔE5, which is the fluctuation ratio of the fifth hysteresis loss to the first hysteresis loss | ΔE5 / ΔE1 | × 100. When H2 (%), H2 can be 15 or less, and H2 × S can be 85 or more and 300 or less.

By adopting the fifth hysteresis loss ΔE5 as an index in the hysteresis loss fluctuation ratio H2, the durability during repeated deformation is stably evaluated in a usage environment in which repeated deformation such as expansion and contraction is continuously performed. I found that I could do it.
Therefore, while setting the hysteresis loss fluctuation ratio H2 to be equal to or lower than the above upper limit value, by setting the product value of the tensile strength S and the hysteresis loss fluctuation ratio H2 to be equal to or higher than the above lower limit value, the mechanical strength and the time of repeated deformation can be obtained. It is possible to realize a resin movable member with excellent durability.

Further, in the resin movable member of the present embodiment, | ΔE5 / ΔE2 | × 100, which is the fluctuation ratio of the fifth hysteresis loss to the second hysteresis loss, can be 80% or less.
By using the hysteresis losses ΔE2 to ΔE5 from the next time onward excluding the first time as an index instead of the hysteresis loss ΔE1 at the time of the first stretching operation, the durability in a usage environment where repeated deformation is continuously performed is stable. I found that it can be evaluated. The detailed mechanism is not clear, but it can be considered as follows. In the initial stretching operation, the composition in the resin movable member tends to be rearranged due to stretching. Therefore, in the second and subsequent stretching operations, the influence of such rearrangement of the composition can be suppressed, and it is considered that the durability during repeated deformation due to the composition of the resin movable member can be better evaluated.
Then, as described above, it is considered that the durability of the resin movable member can be stably evaluated by considering the rate of change of the hysteresis loss when a plurality of stretching operations are repeated from the second time to the fifth time. ..
Therefore, by setting the above | ΔE5 / ΔE2 | × 100 to the above lower limit value or less, the durability of the resin movable member during repeated deformation can be further improved.

According to the present embodiment, it is possible to realize a resin movable member having excellent durability and a structure including such a resin movable member. The resin movable member of the present embodiment is suitable for a usage environment in which the movable member made of resin is used so as to be repeatedly deformed following the movement of a moving part of an instrument or device.

The resin movable member of the present embodiment includes, for example, a part of a medical tube material; a sealing material; a packing material; a connector material; a keypad material; a drive mechanism; a sensor; etc. Can be configured. For example, by applying the resin movable member of the present embodiment to a medical tube, the medical tube is excellent in kink resistance, scratch resistance, insertability and transparency, and further excellent in resilience. Become. Examples of the medical tube include the following medical catheters, manipulators, leads, and the like.

The resin movable member of the present embodiment constitutes a part of, for example, a drive mechanism such as a joint; a wiring mechanism such as a wiring cable and a connector; an operation mechanism such as a manipulator; as an example of robot use such as an industrial robot. can do.

The resin movable member of the present embodiment is used as an example of an electronic device application, for example, a stretchable wiring or wiring substrate used for a wearable device that can be worn on a human body or the like; an optical fiber, a flat cable, or a wiring structure. , Cables such as cable guides; sensors such as touch panels, force sensors, MEMS, seat sensors; etc.

In addition, the resin movable member of the present embodiment is a living product having flexibility, extensibility or foldability such as a packaging material such as a gas barrier film; a cooking utensil; a hose; a fixing belt; a switch; a sheet material; a packing material; Can form part of.

Next, the characteristics of the resin movable member of the present embodiment will be described.

In the resin movable member of the present embodiment, the hysteresis loss at the first extension operation is ΔE1, the hysteresis loss at the second extension operation is ΔE2, and the second hysteresis with respect to the first hysteresis loss. Let | ΔE2 / ΔE1 | × 100, which is the fluctuation ratio of the loss, be H1 (%), and let S (MPa) be the tensile strength measured in accordance with JIS K6251 (2004). At this time, the upper limit of H1 is, for example, 25 or less, preferably 24 or less, more preferably 22 or less, and the lower limit of H1 × S is, for example, 125 or more, preferably 125 or more. It is 130 or more, more preferably 150 or more. As a result, it is possible to realize a resin movable member having excellent mechanical strength and durability against deformation. On the other hand, the lower limit of H1 is not particularly limited, but may be, for example, more than 0 or 1 or more. The upper limit of H1 × S is not particularly limited, but may be, for example, 400 or less, or 300 or less.

Further, in the resin movable member of the present embodiment, the hysteresis loss at the time of the fifth extension operation is ΔE5, which is the fluctuation ratio of the fifth hysteresis loss to the first hysteresis loss | ΔE5 / ΔE1 | × 100. Let be H2 (%). At this time, the upper limit of H2 is, for example, 15 or less, preferably 14.8 or less, more preferably 14.5 or less, and the lower limit of H2 × S is, for example, 85 or more. Yes, preferably 88 or more, and more preferably 90 or more. As a result, it is possible to realize a resin movable member having excellent mechanical strength and durability against deformation during repeated deformation. On the other hand, the lower limit of H2 is not particularly limited, but may be, for example, more than 0 or 1 or more. The upper limit of H2 × S is not particularly limited, but may be, for example, 300 or less, or 200 or less.

Further, in the resin movable member of the present embodiment, the upper limit of | ΔE5 / ΔE2 | × 100, which is the fluctuation ratio of the fifth hysteresis loss to the second hysteresis loss, is, for example, 80% or less, preferably 80% or less. It is 78% or less, more preferably 75% or less. As a result, it is possible to realize a resin movable member having excellent durability during repeated deformation. On the other hand, the lower limit of | ΔE5 / ΔE2 | × 100 is not particularly limited, but may be, for example, more than 0% or 1% or more.

_{The upper limit of the tensile stress M 50} at 50% elongation at room temperature of 25 ° C. measured according to JIS K6251 (2004) of the resin movable member of the present embodiment may be, for example, 1.5 MPa or less. , It may be preferably 1.3 MPa or less, more preferably 1.0 MPa or less, and even more preferably 0.8 MPa or less. As a result, the stress at the initial stage of the start of deformation can be reduced, so that the initial movement of the operation of the instrument or the device can be made good. _{The lower limit of the tensile stress M 50} when the resin movable member is stretched by 50% is not particularly limited, but may be, for example, 0.05 MPa or more, or 0.1 MPa or more. Thereby, the mechanical strength of the resin movable member can be improved.

According to the resin movable member of the present embodiment, the tensile stress M ₅₀ at the time of 50% extension can be reduced. That is, it is possible to reduce the stress in the low strain region of the resin movable member. As a result, it is possible to realize a resin movable member having excellent deformability, which facilitates deformation such as bending and stretching.

_{The upper limit of the tensile stress M 100} at 100% elongation at room temperature of 25 ° C. measured according to JIS K6251 (2004) of the resin movable member of the present embodiment is, for example, 3.0 MPa or less. It is preferably 2.5 MPa or less, more preferably 2.0 MPa or less, and even more preferably 1.9 MPa or less. As a result, the stress in the middle period from the start of deformation to the end of deformation can be reduced, so that the operation of the instrument or device can be performed smoothly. _{The lower limit of the tensile stress M 100} when the resin movable member is 100% stretched is not particularly limited, but may be, for example, 0.1 MPa or more, or 0.3 MPa or more. Thereby, the mechanical strength of the resin movable member can be improved.

_{The upper limit of the tensile stress M 600} at 600% elongation at room temperature of 25 ° C. measured according to JIS K6251 (2004) of the resin movable member of the present embodiment may be, for example, 7.0 MPa or less. It may be preferably 6.5 MPa or less, more preferably 6.0 MPa or less, and even more preferably 5.5 MPa or less. As a result, the stress in the latter stage at the end of deformation can be reduced, so that it can be deformed smoothly and greatly according to the operation of the instrument or equipment, so that operability can be improved, and it can be applied to moving parts with large movement. Can be done. _{The lower limit of the tensile stress M 600} when the resin movable member is stretched by 600% is not particularly limited, but may be, for example, 1.5 MPa or more, or 2.0 MPa or more. Thereby, the mechanical strength of the resin movable member can be improved.

Further, according to the resin movable member of the present embodiment, it is possible to reduce the tensile stress _{M 600} at the time of stress _{M 100,} and 600% elongation tensile during stress _M 50, 100% elongation tensile at 50% elongation .. That is, from the low strain region to the high strain region of the resin movable member, the stress at the initial stage of strain is small, the stress at the middle stage of strain is small, and the stress at the late stage of strain can be small. As a result, it is possible to realize a resin movable member having excellent deformability, which facilitates deformation such as bending and stretching.

According to the present embodiment, it is possible to realize a resin movable member having excellent deformability and durability, and a structure including such a resin movable member.

The lower limit of the tensile strength of the resin movable member of the present embodiment measured in accordance with JIS K6251 (2004) is, for example, 7.0 MPa or more, preferably 7.5 MPa or more, more preferably 7.5 MPa or more. Is 8.0 MPa or more. Thereby, the mechanical strength of the resin movable member can be improved. In addition, the breaking energy can be increased. Therefore, it is possible to realize a resin movable member having excellent durability that can withstand repeated deformation. On the other hand, the upper limit of the tensile strength of the resin movable member is not particularly limited, but may be, for example, 15 MPa or less, or 13 MPa or less. As a result, the operability of various devices and instruments can be improved.

The lower limit of the tear strength of the resin movable member of the present embodiment measured in accordance with JIS K6252 (2001) is, for example, 25 N / mm or more, preferably 30 N / mm or more, more preferably. Is 33 N / mm or more, more preferably 35 N / mm or more. As a result, the scratch resistance and mechanical strength of the resin movable member can be improved. In addition, the durability of the resin movable member during repeated use can be improved. On the other hand, the upper limit of the tear strength of the resin movable member is not particularly limited, but may be, for example, 70 N / mm or less, or 60 N / mm or less. Thereby, various characteristics of the cured product of the resin movable member of the present embodiment can be balanced.

The upper limit of the durometer hardness A of the resin movable member of the present embodiment defined in accordance with JIS K6253 (1997) may be, for example, 80 or less, 75 or less, or 70 or less. On the other hand, the lower limit of the durometer hardness A may be, for example, 10 or more, 15 or more, or 20 or more.
In the high hardness type resin movable member, the durometer hardness A may be, for example, 40 or more and 80 or less, preferably 45 or more and 75 or less, and more preferably 50 or more and 70 or less.
Further, in the low hardness type resin movable member, the durometer hardness A may be, for example, 10 or more and less than 40, preferably 15 or more and 39 or less, and more preferably 20 or more and 38 or less. As a result, the flexibility of the resin movable member can be improved, and it is possible to realize a resin movable member having excellent deformability, which facilitates deformation such as bending and stretching. As a result, the operability of various devices and instruments can be improved.

The upper limit of the elongation at break measured in accordance with JIS K6251 (2004) of the resin movable member of the present embodiment may be, for example, 1500% or less, preferably 1200% or less, and more preferably 1000. It may be less than%. Thereby, the mechanical strength of the resin movable member at room temperature can be improved. On the other hand, the lower limit of the elongation at break is, for example, 200% or more, preferably 250% or more, more preferably 300% or more, and further preferably 400% or more. This makes it possible to improve the high elasticity and durability of the resin movable member at room temperature.

In the present embodiment, for example, the type and blending amount of each component contained in the resin movable member, the method for preparing the composition for forming the resin movable member, the method for producing the resin movable member, and the like are appropriately selected. This makes it possible to control the rate of change in hysteresis loss, tensile stress, breaking energy, tensile strength, tear strength, and hardness. Among these, for example, the type and blending ratio of the resin constituting the resin movable member, the cross-linking density of the resin, the cross-linking structure, etc. are appropriately controlled, and the blending ratio of the inorganic filler and the dispersibility of the inorganic filler are improved. The above-mentioned hysteresis loss change rate, tensile stress, breaking energy, tensile strength, tear strength, hardness, etc. are mentioned as factors for setting the desired numerical range, and further, the content of the inorganic filler (resin component 100). The content) / hardness of the inorganic filler with respect to the part by weight is set to, for example, less than 1, as an element for setting the rate of change in hysteresis loss within a desired numerical range.

Hereinafter, the composition of the resin movable member of the present embodiment will be described.

The resin movable member of the present embodiment may be made of a thermosetting resin or a rubber material. These may be used alone or in combination of two or more.

The thermoplastic resin is selected from the group consisting of, for example, polyolefin resins, polystyrene resins, polyamide resins, polyacetal resins, saturated polyester resins, polyacrylonitrile resins, vinyl chloride resins and polyurethane resins. Can include more than one. These may be used alone or in combination of two or more.

Further, the rubber material may include, for example, one or more selected from the group consisting of silicone rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, and urethane rubber. These may be used alone or in combination of two or more. Among these, acrylic rubber, silicone rubber or urethane rubber can be used from the viewpoint of the balance of characteristics, and silicone rubber is preferably used.

Further, the resin movable member of the present embodiment may be added with an arbitrary component capable of exerting the function of a movable part such as a medical instrument / device, an industrial robot, or an electronic device. For example, from the viewpoint of increasing the mechanical strength, the resin movable member can include an inorganic filler. As the inorganic filler, known ones can be used, and for example, silica particles can be used.

Hereinafter, as an example of the resin movable member of the present embodiment, a case where a silicone rubber-based curable composition is used as the silicone rubber will be described. The resin movable member may be composed of a cured product of a silicone rubber-based curable composition.

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 the 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 the vinyl group serves as a cross-linking point at the time of curing.

The content of the vinyl group of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably, for example, having two or more vinyl groups in the molecule and 15 mol% or less. , 0.01-12 mol%, more preferably. As a result, the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) is optimized, and a network with each component described later can be reliably formed. In the present embodiment, "~" means to include the numerical values at both ends thereof.

In the present specification, the vinyl group content is the mol% of the vinyl group-containing siloxane unit when all the units constituting the vinyl group-containing linear organopolysiloxane (A1) are 100 mol%. .. However, it is considered that there is one vinyl group for each vinyl group-containing siloxane unit.

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

Further, 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 degree of polymerization and specific gravity within the above range, the obtained silicone rubber has heat resistance, flame retardancy, chemical stability, etc. Can be improved.

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

In formula (1), R ¹ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like, and among them, a vinyl group is preferable. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group and the like.

Further, R ² is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, 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.

Further, R ³ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group.

^{Further, examples of the substituent of R 1} and R ^{2 in} the formula (1) include a methyl group, a vinyl group and the like, and examples ^{of the substituent of R 3} include a methyl group and the like.

In the formula (1), a plurality of R ¹ is independent from each other, may be different from each other, it may be 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 10000. Is an integer of. m is preferably 0 to 1000, and n is preferably 2000 to 5000.

Further, as a specific structure of the vinyl group-containing linear organopolysiloxane (A1) represented by the formula (1), for example, the one represented by the following formula (1-1) can be mentioned.

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

Further, the vinyl group-containing linear organopolysiloxane (A1) contains a first vinyl group having a vinyl group content of 2 or more in the molecule and 0.4 mol% or less. 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%. It is preferable to have it. 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 compound having a high vinyl group content. By combining with the chain organopolysiloxane (A1-2), the vinyl groups can be unevenly distributed, and the cross-linking density can be more effectively formed in the cross-linking 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 is used. , A first vinyl group-containing linear organopolysiloxane (A1-1) having two or more in the molecule and containing 0.4 mol% or less, and ^{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 the unit in which 2 is a vinyl group.

Further, the first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol%. The 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 blended in combination (A1-1). The ratio of and (A1-2) is not particularly limited, but for example, the weight ratio of (A1-1) :( A1-2) is preferably 50:50 to 95: 5, and 80:20 to 90: It is more preferably 10.

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.

Further, the vinyl group-containing organopolysiloxane (A) may contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

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

The linear organohydrogenpolysiloxane (B1) has a linear 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, it is a polymer that hydrosilylates with the vinyl group contained in the component blended in the silicone rubber-based curable composition and crosslinks these components.

The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, the weight average molecular weight is preferably 20000 or less, and more preferably 1000 or more and 10000 or less.

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

Further, the linear organohydrogenpolysiloxane (B1) usually preferably has no vinyl group. As a result, it is possible to accurately prevent the cross-linking reaction from proceeding in the molecule of the linear organohydrogenpolysiloxane (B1).

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

In the formula (2), R ⁴ is a hydrocarbon group or a hydride group, in combination a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

Also, R ⁵ is a hydrocarbon group or a hydride group, in combination a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, these. 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. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

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

Further, R ⁶ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. A plurality of R ⁶ are independent from each other, may be different from each other, it may be the same.

^{Examples of the substituent of R 4} , R ⁵ , and R ^{6 in} the formula (2) include a methyl group and a vinyl group, and a methyl group is preferable from the viewpoint of preventing an intramolecular cross-linking reaction.

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

The linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more.

Since the branched organohydrogenpolysiloxane (B2) has a branched structure, it forms a region having a high crosslink density and is a component that greatly contributes to the formation of a sparsely packed structure with a crosslink density in the silicone rubber system. Further, like the linear organohydrogenpolysiloxane (B1), it has a structure (≡Si—H) in which hydrogen is directly bonded to Si, and in addition to the vinyl group of the vinyl group-containing organopolysiloxane (A), silicone. It is a polymer that hydrosilylates with the vinyl group of the component contained in the rubber-based curable composition and crosslinks these components.

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

Further, the branched organohydrogenpolysiloxane (B2) usually preferably has no vinyl group. As a result, it is possible to accurately prevent the cross-linking reaction from proceeding in the molecule of the 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 1 to 3 in the range of integers, m is ^{_{H a (R 7) 3-}} a number of _{SiO 1/2} units, n represents SiO _{4 /} It is a number of _{2 units)}

In 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 in combination thereof. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, 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.

Further, in the equation (c), m is ^{_{H a (R 7) 3-}} a number of _{SiO 1/2} units, n is the number of _{SiO 4/2} units.

The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) differ in that their structures are linear or branched, and are different from Si when the number of Si is 1. The number of alkyl groups R to be bonded (R / Si) is 1.8 to 2.1 for the linear organohydrogenpolysiloxane (B1) and 0.8 to 1 for the branched organohydrogenpolysiloxane (B2). It is in the range of 0.7.

Since the branched organohydrogenpolysiloxane (B2) has a branched structure, for example, 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. 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.

Further, as a specific example of the branched organohydrogenpolysiloxane (B2), those having a structure represented by the following formula (3) can be mentioned.

In formula (3), R ⁷ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group combining these, or a hydrogen atom. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. Examples of the substituent of R ⁷ include a methyl group and the like.

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

Further, in the equation (3), "-O-Si≡" indicates that Si has a branched structure that spreads three-dimensionally.

The branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more.

Further, 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 organohydrogenpoly are added to 1 mol of the vinyl group in the vinyl group-containing linear organopolysiloxane (A1). The total amount of hydride groups of siloxane (B2) is preferably 0.5 to 5 mol, more preferably 1 to 3.5 mol. This ensures that a crosslinked network is formed between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organopolysiloxane (A1). Can be made to.

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

The silica particles (C) are not particularly limited, but for example, fumed silica, calcined silica, precipitated silica and the like are used. These may be used alone or in combination of two or more.

The specific surface area of the silica particles (C) according to the BET method ^{is preferably, for example, 50 to 400 m 2} / g, and more preferably 100 to 400 m ² / g. Further, the average primary particle size 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 size, 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 hydrolyzing group is hydrolyzed by water to become a hydroxyl group, and this hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl group on the surface of the silica particles (C), whereby the surface of the silica particles (C) can be modified.

Further, the silane coupling agent (D) can include a silane coupling agent having a hydrophobic group. As a result, this hydrophobic group is imparted to the surface of the silica particles (C), so that 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). Aggregation due to bonding is reduced), and as a result, it is presumed that the dispersibility of the silica particles in the silicone rubber-based curable composition is improved. As a result, the interface between the silica particles and the rubber matrix is increased, and the reinforcing effect of the silica particles is increased. Further, it is presumed that the slipperiness of the silica particles in the matrix is improved when the rubber matrix is deformed. Then, by improving the dispersibility and slipperiness of the silica particles (C), the mechanical strength (for example, tensile strength, tear strength, etc.) of the silicone rubber due to the silica particles (C) is improved.

Further, the silane coupling agent (D) can include a silane coupling agent having a vinyl group. As a result, a vinyl group is introduced on the surface of the silica particles (C). Therefore, when the silicone rubber-based curable composition is cured, that is, the vinyl group contained in the vinyl group-containing organopolysiloxane (A) and the hydride group contained in the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction. When the network (crosslinked structure) formed by these 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) will also be incorporated into the siloxane. As a result, it is possible to reduce the hardness and increase the modulus of the formed silicone rubber.

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.

Examples of the silane coupling agent (D) include those represented by the following formula (4).

Y _n- Si- (X) _4-n ... (4)
In the above equation (4), n represents an integer of 1 to 3. Y represents any functional group having 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. 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 in which these are combined, and examples thereof include a methyl group, an ethyl group, a propyl group, a phenyl group, and the like. Methyl groups are preferred.

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

Further, examples of the hydrolyzable group include an alkoxy group such as a methoxy group and an ethoxy group, a chloro group or a silazane group, and among them, a silazane group is preferable because it has high reactivity with the silica particles (C). Those having a silazane group as a hydrolyzable group have _{two structures of (Y n −} Si−) in the above formula (4) due to their structural characteristics.

Specific examples of the silane coupling agent (D) represented by the above formula (4) include, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, and methyltri as those having a hydrophobic group as a functional group. Ekoxysilanes such as ethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane; methyltrichlorosilane , Dimethyldichlorosilane, trimethylchlorosilane, chlorosilanes such as phenyltrichlorosilane; hexamethyldisilazane, examples of which have a vinyl group as a functional group include methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxy Ekoxysilanes such as propylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane, vinylmethyldichlorosilane; divinyltetramethyldi Examples thereof include silazan, but in consideration of the above description, hexamethyldisilazane is particularly preferable as having a hydrophobic group, and divinyltetramethyldisilazane is preferable as having a vinyl group.

<< 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 the platinum compound (E) is a catalytic component that acts as a catalyst during curing. The amount of platinum or platinum compound (E) added is the amount of catalyst.

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

As the platinum or the platinum compound (E), only one type may be used alone, or two or more types may be used in combination.

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

Water (F) functions as a dispersion medium for dispersing each component contained in the silicone rubber-based curable composition, and is a component that 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.

Further, the silicone rubber-based curable composition of the present embodiment may contain known additive components to be blended in the silicone rubber-based curable composition in addition to the above-mentioned components (A) to (F). For example, diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, mica and the like can be mentioned. 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, based on 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). It may be less than or equal to, and more preferably 35 parts by weight or less. Thereby, the tear strength and the tensile permanent strain can be balanced. The lower limit of the content of the silica particles (C) is not particularly limited with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), but may be, for example, 20 parts by weight or more.

The silane coupling agent (D) is preferably contained in a proportion of, for example, 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 parts by weight or more and 40 parts by weight or less.
Thereby, the dispersibility of the silica particles (C) in the silicone rubber-based curable composition can be surely improved.

The content of the organohydrogenpolysiloxane (B) is specifically, for example, with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), the silica particles (C) and the silane coupling agent (D). , 0.5 part by weight or more and preferably 20 parts by weight or less, and more preferably 0.8 parts by weight or more and 15 parts by weight or less. When the content of (B) is within the above range, a more effective curing reaction may be possible.

The content of platinum or the platinum compound (E) means the amount of the catalyst and can be appropriately set. Specifically, the vinyl group-containing organopolysiloxane (A), the silica particles (C), and the silane coupling agent ( The amount of the platinum group metal in this component is 0.01 to 1000 ppm, preferably 0.1 to 500 ppm, based on the total amount of D). By setting the content of platinum or the platinum compound (E) to the above lower limit value or more, the obtained silicone rubber composition can be sufficiently cured. By setting the content of platinum or the platinum compound (E) to the above upper limit value or less, the curing rate of the obtained silicone rubber composition can be improved.

Further, when water (F) is contained, the content thereof can be appropriately set. Specifically, for example, 10 to 100 parts by weight with respect to 100 parts by weight of the silane coupling agent (D). It is preferably in the range of 30 to 70 parts by weight, and more preferably in the range of 30 to 70 parts by weight. As a result, the reaction between the silane coupling agent (D) and the silica particles (C) can proceed more reliably.

<Manufacturing method of silicone rubber>
Next, the method for producing the silicone rubber of the present embodiment will be described.
As a method for producing a silicone rubber of the present embodiment, a silicone rubber-based curable composition is prepared, and the silicone rubber-based curable composition is cured to obtain a silicone rubber.
The details will be described below.

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

[1] For example, a vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) are weighed in a predetermined amount, and then kneaded by an arbitrary kneading device. A kneaded product containing each of 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). As a result, the dispersibility of the silica particles (C) in the vinyl group-containing organopolysiloxane (A) is further improved.

Further, when obtaining this kneaded product, water (F) may be added to the kneaded product of each component (A), (C), and (D), if necessary. As a result, the reaction between the silane coupling agent (D) and the silica particles (C) can proceed more reliably.

Further, it is preferable that the kneading of each component (A), (C), and (D) goes 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) are combined. By-products produced by the reaction can be reliably removed from the kneaded product. Then, 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.

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

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.

Further, 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 of 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 under the above-mentioned conditions, the effect can be obtained more remarkably.

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

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

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

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

By setting the temperature within the above range in the above step [1] and the above step [2], the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be made more accurate. Can be prevented or suppressed. Further, in the above steps [1] and [2], by setting the kneading time within the above range, each component (A) to (E) is more reliably dispersed in the silicone rubber-based curable composition. Can be done.

The kneading device 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 pressurized kneader, or the like can be used.

Further, in this step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded product. As a result, 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 the present embodiment, the curing step of the silicone rubber-based curable resin composition is, for example, heating at 100 to 250 ° C. for 1 to 30 minutes (primary curing) and then post-baking (secondary) at 200 ° C. for 1 to 4 hours. It is done by curing).
By going through the above steps, the silicone rubber of the present embodiment can be obtained.

As a result of the examination by the present inventor, the following findings were obtained. It has been found that reducing the amount of filler in the silicone rubber can reduce the hardness and the tensile stress, but on the other hand, the tear strength is lowered and the durability of the silicone rubber is lowered.

Therefore, as a result of diligent studies, by appropriately selecting a resin composition such as vinyl group-containing organopolysiloxane (A), the crosslink density and uneven distribution of the crosslink structure can be controlled, and low stress and low hardness in a wide strain region can be obtained. We have found that the tear strength of silicone rubber can be increased while achieving this. It was also found that the tensile strength of the silicone rubber can be increased. Although the detailed mechanism is not clear, the uneven distribution of the crosslinked structure can be controlled by using the high vinyl group-containing organopolysiloxane and the low vinyl group-containing vinyl group-containing organopolysiloxane together, so that the silicone rubber can be torn while reducing the hardness. It is thought that the strength can be increased. In this way, the breaking energy of the silicone rubber can be increased by increasing the tear strength while maintaining other physical properties.

Further, in the present embodiment, for example, by reducing the amount of filler, the tensile stress in the initial strain is reduced, and by controlling the crosslink density of the resin and the uneven distribution of the crosslinked structure, the tensile stress in the late strain is controlled. Can be reduced.

In the present embodiment, for example, by appropriately selecting the type and blending 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 silicone rubber, and the like. It is possible to control the rate of change in hysteresis loss, tensile stress, breaking energy, tensile strength, tear strength, and hardness. Among these, for example, a low vinyl group-containing linear organopolysiloxane (A1-1) and a high vinyl group-containing linear organopolysiloxane (A1-2) may be used in combination, and vinyl having a vinyl group at the terminal may be used in combination. By using the group-containing organopolysiloxane (A), the cross-linking density of the resin and the uneven distribution of the cross-linked structure can be controlled, the timing of adding the vinyl group-containing organopolysiloxane (A), and the blending ratio of the silica particles (C). , The 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, proceeds more reliably. It is mentioned as an element for setting the above-mentioned rate of change in hysteresis loss, tensile stress, breaking energy, tensile strength, tear strength, and hardness within a desired numerical range.

Further, in the present embodiment, the upper limit of the content of the silica particles (C) may be, for example, 55 parts by weight or less, preferably 53 parts by weight, based on 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). It may be 10 parts by weight or less, and more preferably 50 parts by weight or less. Thereby, the tear strength and the tensile permanent strain can be balanced. The lower limit of the content of the silica particles (C) is not particularly limited with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), but may be, for example, 10 parts by weight or more, and 20 parts by weight. The above may be sufficient.
Here, the content of the silica particles (C) is defined as X (parts by weight) with respect to 100 parts by weight of the vinyl group-containing organopolysiloxane (A), and the cured product of the silicone-based curing composition is defined by JIS K6253. When the durometer hardness A is Y, the filler amount / hardness described above is, for example, less than 1, more preferably 0.95 or less, still more preferably 0.91 or less when expressed in X / Y. Can be. For example, setting X (filler amount) / Y (hardness) to less than 1 is mentioned as an element for setting the rate of change in hysteresis loss within a desired numerical range, although the reason is not clear.

Further, in the resin movable member of the present embodiment, H3 (%) is defined as | ΔE5 / ΔE2 | × 100, which is the fluctuation ratio of the fifth hysteresis loss to the second hysteresis loss. At this time, H3 × (X / Y) may be, for example, 63 or less, preferably 60 or less, and more preferably 58 or less. As a result, it is possible to realize a resin movable member having excellent durability during repeated deformation. On the other hand, the lower limit of | ΔE5 / ΔE2 | × 100 is not particularly limited, but may be, for example, 10 or more, or 20 or more.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above can be adopted.
Hereinafter, an example of the reference form will be added.
1. 1. The following stretching operation is repeated 5 times, the hysteresis loss at the first stretching operation is ΔE1, the hysteresis loss at the second stretching operation is ΔE2, and the second hysteresis with respect to the first hysteresis loss. Let H1 (%) be the fluctuation ratio of loss | ΔE2 / ΔE1 | × 100.
When the tensile strength measured in accordance with JIS K6251 (2004) is S (MPa),
A movable resin member having H1 of 25 or less and H1 × S of 125 or more and 400 or less.
(Extension operation)
The stretching operation is an operation in which the dumbbell test piece is stretched from a displacement amount of 0% to 500% at a room temperature of 25 ° C. and a stretching speed of 1000 mm / min, and then contracted by a displacement amount of 500% to 0%. ..
2. 1. 1. The resin movable member described in 1.
When the hysteresis loss at the time of the fifth extension operation is ΔE5 and the fluctuation ratio of the fifth hysteresis loss to the first hysteresis loss | ΔE5 / ΔE1 | × 100 is H2 (%).
A resin movable member having H2 of 15 or less and H2 × S of 85 or more and 300 or less.
3. 3. 1. 1. Or 2. The resin movable member described in 1.
A resin movable member in which | ΔE5 / ΔE2 | × 100, which is the fluctuation ratio of the fifth hysteresis loss to the second hysteresis loss, is 80% or less.
4. 1. 1. From 3. The resin movable member according to any one of the above.
A movable resin member having a tear strength of 25 N / mm or more measured in accordance with JIS K6252 (2001).
5. 1. 1. From 4. The resin movable member according to any one of the above.
A resin movable member having a durometer hardness A of 10 or more and 80 or less specified in accordance with JIS K6253 (1997).
6. 1. 1. From 5. The resin movable member according to any one of the above.
A movable resin member having a breaking elongation of 200% or more and 1500% or less measured in accordance with JIS K6251 (2004).
7. 1. 1. From 6. The resin movable member according to any one of the above.
A movable member made of resin, including an inorganic filler.
8. 1. 1. From 7. A structure comprising the resin movable member according to any one of the above.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the description of these Examples.

The raw material components used in the examples and comparative examples shown in Table 1 are shown below.
(Vinyl group-containing organopolysiloxane (A))
Low vinyl group-containing linear organopolysiloxane (A1-1a): In-chain vinyl group-containing dimethylpolysiloxane synthesized by synthesis scheme 1 (with a structure represented by formula (1-1), ^{only R 2} (inside the chain)) Structure that is a vinyl group)
Low vinyl group-containing linear organopolysiloxane (A1-1b): Terminal vinyl group-containing dimethylpolysiloxane synthesized by synthesis scheme 2 (structure represented by formula (1-1), ^{only R 1} (terminal) is vinyl group Structure)
High vinyl group-containing linear organopolysiloxane (A1-2a): Vinyl group-containing dimethylpolysiloxane synthesized by synthesis scheme 3 (in the structure represented by the formula (1-1), R ¹ and R ² are vinyl groups. Construction)

(Organohydrogenpolysiloxane (B))
Organohydrogenpolysiloxane (B): "TC-25D" manufactured by Momentive Co., Ltd.

(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., "AEROSIL300"

(Silane Coupling Agent (D))
Silane coupling agent (D-1): Hexamethyldisilazane (HMDZ), manufactured by Gelst, "HEXAMETHYLDISILAZANE (SIH6110.1)"
Silane coupling agent (D-2): Divinyltetramethyldisilazane, manufactured by Gelst, "1,3-DIVINYLTETRAMETHYLDISILAZANE (SID4612.0)"

(Platinum or platinum compound (E))
Platinum or platinum compound (E): Platinum compound, manufactured by Momentive, "TC-25A"

(Synthesis of vinyl group-containing organopolysiloxane (A))
[Synthesis scheme 1: Synthesis of linear organopolysiloxane (A1-1a) containing low vinyl group]
A low vinyl group-containing linear organopolysiloxane (A1-1a) was synthesized according to the following formula (6).
That is, in a 300 mL separable flask having a cooling tube and a stirring blade substituted with Ar gas, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane, 2,4,6,8-tetramethyl2,4,6,8- 0.086 g (0.25 mmol) of tetravinylcyclotetrasiloxane and 0.1 g of potassium silicate were added, the temperature was raised, and the mixture was stirred at 120 ° C. for 30 minutes. At this time, an increase in viscosity was confirmed.
Then, the temperature was raised to 155 ° C., and stirring was continued for 3 hours. Then, after 3 hours, 0.1 g (0.6 mmol) of hexamethyldisiloxane was added, and the mixture was further stirred at 155 ° C. for 4 hours.
After 4 hours, the mixture was diluted with 250 mL of toluene and washed 3 times with water. The organic layer after washing was washed several times with 1.5 L of methanol to reprecipitate and separate the oligomer and the polymer. The resulting polymer was dried under reduced pressure overnight at 60 ° C., to obtain a low vinyl-containing linear organopolysiloxane (A1-1a) (Mn = 2,5 × 10 5, Mw = 5,0 × 10 5 ). The vinyl group content calculated by 1 H-NMR spectrum measurement was 0.18 mol%.

[Synthesis Scheme 2: Synthesis of Linear Organopolysiloxane (A1-1b) Containing Low Vinyl Group]
In the above synthesis step (A1-1a), 2,4,6,8-tetramethyl 2,4,6,8-tetravinylcyclotetrasiloxane was not used, and 1,3-divinyl was used instead of hexamethyldisiloxane. A low vinyl group-containing linear organopolysiloxane according to the following formula (7) in the same manner as in the synthesis step of (A1-1a) except that 0.1 g (0.6 mmol) of tetramethyldisiloxane was used. (A1-1b) was obtained. ^{(Mn = 2,2 × 10 5,} Mw = 4,8 × 10 5). The vinyl group content calculated by 1 H-NMR spectrum measurement was 0.04 mol%.

[Synthesis scheme 3: Synthesis of linear organopolysiloxane (A1-2a) containing high vinyl group]
In the above synthesis step (A1-1a), 0.86 g (2.5 mmol) of 2,4,6,8-tetramethyl 2,4,6,8-tetravinylcyclotetrasiloxane was used, and hexamethyldi was used. High vinyl according to the following formula, except that 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was used instead of siloxane, in the same manner as in the synthesis step of (A1-1a). A group-containing linear organopolysiloxane (A1-2a) was synthesized. ^{(Mn = 2,3 × 10 5,} Mw = 5,0 × 10 5). The vinyl group content calculated by 1 H-NMR spectrum measurement was 0.93 mol%.

(Preparation of silicone rubber-based curable composition)
In Examples and Comparative Examples, the silicone rubber-based curable composition was prepared as follows. First, a mixture of 95% vinyl group-containing organopolysiloxane (A), a silane coupling agent (D) and water (F) is kneaded in advance at the ratio shown in Table 1, and then silica particles (C) are added to the mixture. Was further kneaded to obtain a kneaded product (silicone rubber compound).
Here, the kneading after the addition of the silica particles (C) is carried out in the first step of kneading for 1 hour under the condition of 60 to 90 ° C. under a nitrogen atmosphere for the coupling reaction, and the removal of the by-product (ammonia). Therefore, it is carried out by going through the second step of kneading for 2 hours under the condition of 160 to 180 ° C. under a reduced pressure atmosphere, and then cooling, and the remaining 5% of the vinyl group-containing organopolysiloxane (A) is added twice. It was added separately and kneaded for 20 minutes.
Subsequently, organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) were added to 100 parts by weight of the obtained kneaded product (silicone rubber compound) at the ratios shown in Table 1, and the mixture was kneaded with a roll. A silicone rubber-based curable composition was obtained.

Hereinafter, the silicone rubber-based curable compositions of the obtained Examples and Comparative Examples were evaluated as follows. The evaluation results are shown in Table 1.

(Making silicone rubber)
The obtained silicone rubber-based curable composition was pressed at 150 ° C. and 10 MPa for 20 minutes to form a sheet and first cured. Subsequently, it was heated at 200 ° C. for 4 hours and secondarily cured. From the above, a sheet-shaped silicone rubber (cured product of a silicone rubber-based curable composition) having a predetermined thickness shown in Table 1 was obtained. The following evaluation was performed on the obtained sheet-shaped silicone rubber. The evaluation results are shown in Table 1. Tensile strength and elongation at break were measured with three samples, and the average value of the three was taken as the measured value. The tear strength was measured with 5 samples, and the average value of 5 was used as the measured value. Further, regarding the hardness, two samples were used, and each sample was measured at n = 5, and the average value of 10 measurements was taken as the measured value. The average value for each is shown in Table 1.

(Measurement method of hysteresis loss)
Hysteresis loss was calculated from the measured values obtained by the following stretching operation based on the following calculation method.
[Extension operation]
As shown in FIG. 1A, a dumbbell-shaped test piece 10 was produced using the sheet-shaped silicone rubber obtained in the production of the silicone rubber.
Next, as shown in FIG. 1 (b), the test piece 10 is stretched at a constant speed (1000 mm / min) from a displacement amount of 0% to 500% in accordance with JIS K6251 (2004), and then, as shown in FIG. The stretching operation of contracting the displacement amount from 500% to 0% at a constant speed (1000 mm / min) by removing force was repeated 5 times in succession, and the stress applied to the test piece 10 was measured at room temperature of 25 ° C.
The stretching operation test was performed N times (N = 3), and the average value was adopted.
Testing machine: Autograph AG5kNX (manufactured by Shimadzu Corporation, "model number AG-5kNX")
Initial value: 60 mm (distance between chucks), 0% elongation rate extension: 360 mm (distance between chucks), 500% extension rate extension speed: 1000 mm / min Extension time: 36 seconds / cycle (1 cycle is the initial value → At the time of extension → initial value)

[Hysteresis loss calculation method]
The hysteresis loss is the Nth test force-stroke curve obtained from the Nth extension operation described above (where, the test force [N] is the stress when the test piece 10 is pulled, and the stroke [mm]. _{] Is the energy EN UP} (mJ) at the time of extension and the energy EN _DOWN (mJ) at the time of decompression from the area (having the dimension of energy) obtained by integrating the test piece 10 (the distance at which the test piece 10 is pulled). Was calculated, and the hysteresis loss ΔEN (mJ) at the Nth extension operation was set to | EN _{UP- EN DOWN} |. However, N is an integer of 1 to 5.

Here, the hysteresis loss at the first extension operation is ΔE1, the hysteresis loss at the second extension operation is ΔE2, and the hysteresis loss at the fifth extension operation is ΔE5. Further, let H1 (%) be | ΔE2 / ΔE1 | × 100, which is the fluctuation ratio of the second hysteresis loss to the first hysteresis loss, and | ΔE5, which is the fluctuation ratio of the fifth hysteresis loss to the first hysteresis loss. / ΔE1 | × 100 was defined as H2 (%), and | ΔE5 / ΔE2 | × 100, which is the fluctuation ratio of the fifth hysteresis loss to the second hysteresis loss, was defined as H3 (%).

(Breaking elongation)
Using the obtained sheet-shaped silicone rubber, a dumbbell-shaped No. 3 test piece was prepared in accordance with JIS K6251 (2004), and the obtained dumbbell-shaped No. 3 test piece was stretched at break at room temperature of 25 ° C. Was measured. The breaking elongation was calculated by [moving distance between chucks (mm)] ÷ [initial distance between chucks (60 mm)] × 100. The unit is%.

(Tensile stress)
Using the obtained sheet-shaped silicone rubber, a dumbbell-shaped No. 3 test piece was prepared in accordance with JIS K6251 (2004), and the obtained dumbbell-shaped No. 3 test piece was prepared at room temperature of 25 ° C. The tensile stress M ₁₀₀ at 100% elongation was measured. The unit is MPa.

(Tensile strength)
Using the obtained sheet-shaped silicone rubber, a dumbbell-shaped No. 3 test piece was prepared in accordance with JIS K6251 (2004), and the tensile strength of the obtained test piece was measured at room temperature of 25 ° C. The unit is MPa. This tensile strength is indicated by S (MPa) in the table.

(Tear strength)
Using the obtained sheet-shaped silicone rubber, a crescent-shaped test piece was prepared according to JIS K6252 (2001), and the tear strength of the obtained crescent-shaped test piece was measured at room temperature of 25 ° C. The unit is N / mm.

(Hardness: Durometer hardness A)
Six sheets of the obtained sheet-shaped silicone rubber were laminated to prepare a test piece. The hardness of the obtained test piece was measured at room temperature of 25 ° C. according to JIS K6253 (1997).

<Repeated deformation test>
Using the silicone rubber-based curable composition obtained in each Example and each Comparative Example, it was cured under the conditions of 170 ° C. for 5 minutes and 200 ° C. for 4 hours, and a tubular member having a thickness of 1 mm × an inner diameter of 5 mm. (Tube) was created. A test was conducted in which the obtained tubular member was connected to a tube joint (AS ONE Corporation: quick type, model number S, connection tube inner diameter φ3, 4, 5). The attachment / detachment of the tubular member to the tube joint was repeated 4 times. After connecting the tube joint and the tubular member for the fifth time, water was allowed to flow through the tubular member, and the presence or absence of water leakage from the connecting portion was confirmed. Those without cracks in the tube when attached to or detached from the tubular member were marked with ⊚, those with cracks of 2 mm or less in the tube were marked with ◯, and those with cracks of 2 mm or more in the tube were marked with x. When water was flowed through the tube joint for the fifth time after the tubular member was connected, the one with no water leakage from the connection part was marked with ◯, and the one with water leakage was marked with x.

From the above, the resin movable members obtained from the silicone rubber-based curable compositions of Examples 1 to 8 have higher mechanical strength and durability than those of Comparative Examples 1 to 3 even after repeated use. Therefore, it was found that these balances are excellent. Therefore, it was found that the resin movable member of each embodiment is suitable as a movable member constituting a movable part of various instruments and devices.

Although the present invention has been described in more detail based on the above examples, these are examples of the present invention, and various configurations other than the above can be adopted.

10 test pieces

Claims (9)

It is a resin movable member made of silicone rubber.
The silicone rubber is a cured product of a silicone rubber-based curable composition.
The silicone rubber-based curable composition contains a vinyl group-containing organopolysiloxane (A), an organohydrogenpolysiloxane (B), and silica particles (C).
The content of the silica particles (C) is defined as X (parts by weight) with respect to 100 parts by weight of the vinyl group-containing organopolysiloxane (A), and is defined by JIS K6253 of the cured product of the silicone-based curing composition. When the durometer hardness A is Y, X / Y is 0.91 or less.
Do the following stretching procedure was repeated twice, and the hysteresis loss at the time of the first round of the decompression operations and ΔE1, the hysteresis loss at the time of the extension operation of the second and ΔE2, 2 round of hysteresis for the first time of the hysteresis loss Let H1 (%) be the fluctuation ratio of loss | ΔE2 / ΔE1 | × 100.
When the tensile strength measured in accordance with JIS K6251 (2004) is S (MPa),
H1 is 25 or less, and H1 × S is 130 or more and 400 or less.
The breaking elongation measured according to JIS K6251 (2004) is 200% or more and 1000% or less.
Movable member made of resin.
(Extension operation)
The stretching operation is an operation in which the dumbbell test piece is stretched from a displacement amount of 0% to 500% at a room temperature of 25 ° C. and a stretching speed of 1000 mm / min, and then contracted by a displacement amount of 500% to 0%. .. The resin movable member according to claim 1.
When the above stretching operation is repeated 5 times and the hysteresis loss at the time of the 5th stretching operation is ΔE5, it is the fluctuation ratio of the 5th hysteresis loss to the 1st hysteresis loss | ΔE5 / ΔE1 | × 100. When is H2 (%)
A resin movable member having H2 of 15 or less and H2 × S of 85 or more and 300 or less. The resin movable member according to claim 1 or 2.
When the above stretching operation is repeated 5 times and the hysteresis loss at the time of the 5th stretching operation is ΔE5, it is the fluctuation ratio of the 5th hysteresis loss to the 2nd hysteresis loss | ΔE5 / ΔE2 | × 100. However, the resin movable member is 80% or less. The resin movable member according to any one of claims 1 to 3.
A movable resin member having a tear strength of 25 N / mm or more measured in accordance with JIS K6252 (2001). The resin movable member according to any one of claims 1 to 4.
A resin movable member having a durometer hardness A specified in accordance with JIS K6253 (1997) of 10 or more and less than 40. The resin movable member according to any one of claims 1 to 5.
A movable resin member used to form a tubular member. The resin movable member according to any one of claims 1 to 6.
A movable member made of resin, including an inorganic filler. The resin movable member according to any one of claims 1 to 7.
The upper limit of the amount of the previous SL silica particles (C) is, relative to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), than 60 parts by weight,
Movable member made of resin. A structure comprising the resin movable member according to any one of claims 1 to 8.

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