JP2016002103A - Addition-curable silicone rubber composition for manufacturing medical balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an addition-curable silicone rubber composition to make the silicone rubber for use in a medical balloon catheter, having a low modulus with a small permanent elongation, achieving high extensibility and high flexibility.SOLUTION: An addition-curable silicone rubber composition for manufacturing a medical balloon catheter is mainly composed of: an organopolysiloxane (A) in a crude rubber state at room temperature, which contains silicon atom-bonded alkenyl groups only at molecular chain ends; an organopolysiloxane (B) in a crude rubber state at room temperature, which contains silicon atom-bonded alkenyl groups at molecular chain ends and in side chains of a molecular chain; an addition reaction type curing agent (C); a reinforcing silica (D) having a BET specific surface area of 50 m/g or more; and an organosiloxane or organosilane, or a mixture thereof (E). The composition is press-cured at 120°C for 10 minutes, and then post cured at 150°C for 1 hour to produce a cured material having a durometer hardness A of 5 to 30.

Description

  The present invention relates to an addition reaction curable type curable silicone rubber composition which has a low modulus, little permanent elongation, high extensibility and high flexibility, and gives a silicone rubber used for a medical balloon catheter.

  Silicone rubber is superior in physiological inertness (non-toxic), weather resistance, durability, releasability, heat resistance, electrical properties, low compression set, cold resistance, etc. It is used in various fields such as materials, electrical / electronic parts, automobile parts, OA equipment parts, food utensils.

  Among these, addition-curing type silicone rubber compositions that are cured by hydrosilylation reaction can accelerate curing by heating, so that the productivity is good and, like organic peroxide curing type silicone rubber compositions, Since by-products due to the decomposition of the organic peroxide are not generated, it is excellent in safety, and thus is particularly useful for a medical device such as a balloon catheter.

  A medical balloon catheter is a flexible catheter having a lumen with a balloon (balloon) attached to the tip. The heart is stopped when expanding a body lumen such as a narrowed blood vessel or performing an open heart operation. It is mainly used for injection of myocardial protective fluid into the body, anesthesia for postoperative pain, administration of analgesics, administration of anticancer agents, etc., for example, for its use, elongation characteristics such as high elongation, low permanent elongation, low modulus, high Mechanical properties such as flexibility and high tensile strength are required.

  On the other hand, for example, a medical balloon catheter made of a rubber composition such as silicone, polyurethane, polyester, polytetrafluoroethylene or the like has been proposed (Patent Document 1: Japanese Patent Laid-Open No. 2000-327783, 2: Patent No. 1). No. 5139992, 3: JP 2013-198718 A, 4: JP 2001-31737 A, 5: JP 6-287440 A, 6: JP 6-218037 A, 7: Special Table 2005. 520639 and 8: Japanese Patent Application Laid-Open No. 2002-212365), when a mechanical characteristic required for a medical balloon catheter is imparted, since the permanent elongation is large, the balloon is expanded when the balloon is expanded after being expanded in the blood vessel. There are problems such as stagnation in the bloodstream and blood flow stagnation, resulting in blood clots. The above mentioned required properties required for over emissions catheter was not to simultaneously satisfactory.

JP 2000-327783 A Japanese Patent No. 5139992 JP 2013-198718 A JP 2001-31737 A JP-A-6-287440 JP-A-6-218037 JP 2005-52039A JP 2002-212365 A

  The present invention has been made in view of the above circumstances, and is an addition-curable silicone rubber that has a low modulus, little permanent elongation, has high extensibility and high flexibility, and provides a silicone rubber used for a medical balloon catheter. An object is to provide a composition.

  As a result of intensive studies to achieve the above object, the present inventors have found that an organopolysiloxane in the form of a raw rubber at room temperature containing an alkenyl group only at the molecular chain end and an alkenyl group at the molecular chain end and molecular chain side chain Combined with a raw rubber-like organopolysiloxane at room temperature containing a group at a predetermined ratio, it has low modulus, little permanent elongation, high extensibility and flexibility, and is suitably used as a medical balloon catheter. The present inventors have found that an addition reaction curable curable silicone rubber composition giving a silicone rubber can be obtained.

That is, the present invention provides the following addition-curable silicone rubber composition for producing a medical balloon catheter.
[1]
(A) 85 to 97 parts by mass of a raw rubber-like organopolysiloxane having an average polymerization degree of 2,000 or more and containing an alkenyl group bonded to at least two silicon atoms in one molecule only at the molecular chain terminal (B) A raw rubber-like organopolysiloxane having an average degree of polymerization of 2,000 or more and containing alkenyl groups bonded to at least three silicon atoms in one molecule at the molecular chain terminal and molecular chain side chain. ~ 3 parts by mass (however, the total of component (A) and component (B) is 100 parts by mass)
(C) Addition reaction type curing agent Effective amount (D) Reinforcing silica having specific surface area of 50 m ² / g or more by BET adsorption method (A), 1 to 40 parts by mass with respect to 100 parts by mass in total of components (B) (E) The following general formula (IV):
R ⁵ O (SiR ⁴ ₂ O) _m R ⁵ (IV)
(Wherein R ⁴ is the same or different unsubstituted or substituted monovalent hydrocarbon group, m is a positive number of 1 to 50, and R ⁵ is an alkyl group or a hydrogen atom.)
The organosiloxane or organosilane, or a mixture thereof represented by the formula (A), 100 parts by mass of the component (B), 0.1 to 50 parts by mass as a main component, at 120 ° C. for 10 minutes Addition-curing silicone for the production of medical balloon catheters that gives a cured product with a durometer A hardness meter of 5-30 measured according to JIS K6249 by post-curing at 150 ° C. for 1 hour after press curing Rubber composition.
[2]
After press curing at 120 ° C. for 10 minutes, post-curing at 150 ° C. for 1 hour, extending to 350% based on JIS K6301, holding for 24 hours, then removing the force and leaving for 10 minutes The addition-curable silicone rubber composition for producing a medical balloon catheter according to [1], which gives a cured product having an elongation of less than 15%.
[3]
After curing at 120 ° C. for 10 minutes, post curing at 150 ° C. for 1 hour gives a cured product having a 600% modulus of less than 1.5 MPa measured according to JIS K6249 [1] or [2] The addition-curable silicone rubber composition for manufacturing a medical balloon catheter as described.
[4]
After curing at 120 ° C. for 10 minutes, post curing at 150 ° C. for 1 hour gives a cured product having an elongation at break measured based on JIS K6249 of 800% or more [1] to [3] The addition-curable silicone rubber composition for producing a medical balloon catheter according to any one of the above.

  According to the addition-curable silicone rubber composition for producing a medical balloon catheter of the present invention, a silicone rubber having a low modulus, little permanent elongation, high extensibility and flexibility is provided. It is suitable for forming a balloon catheter.

Hereinafter, the present invention will be described in more detail.
Component (A) is an organopolysiloxane in the form of a raw rubber at room temperature having an average degree of polymerization of 2,000 or more and containing an alkenyl group bonded to at least two silicon atoms in one molecule only at the molecular chain end. Preferably, it is represented by the following average composition formula (I).
R ¹ _a SiO _{(4-a) / 2} (I)
(In the formula, R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05.)

In the above average composition formula (I), R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, usually having 1 to 12 carbon atoms, particularly preferably having 1 to 8 carbon atoms. Are alkyl groups such as methyl, ethyl, propyl, butyl, hexyl and octyl, cycloalkyl such as cyclopentyl and cyclohexyl, alkenyl such as vinyl, allyl and propenyl, cyclo An aryl group such as an alkenyl group, a phenyl group or a tolyl group, an aralkyl group such as a benzyl group or a 2-phenylethyl group, or a part or all of the hydrogen atoms of these groups is a halogen atom such as fluorine or chlorine or a cyano group For example, a chloromethyl group, a trifluoropropyl group, a cyanoethyl group, and the like substituted with a methyl group, a vinyl group, a phenyl group, a trifluoro group, etc. Preferably propyl, especially methyl, vinyl is preferable.

  Particularly, the organopolysiloxane of component (A) needs to contain an alkenyl group bonded to at least two silicon atoms in one molecule only at the molecular chain terminal, and the number of silicon atoms in the molecule (or molecule 0.001 to 0.5 mol%, more preferably 0.001 to 0.1 mol%, still more preferably 0.001 to 0.05 mol% of the alkenyl group, It contains. The alkenyl group is preferably a vinyl group or an allyl group, and more preferably a vinyl group.

Further, among the monovalent hydrocarbon groups represented by R ¹ in the molecule, 50 mol% or more is preferably a methyl group, more preferably 80 mol% or more is a methyl group, and other than alkenyl groups. More preferably, all R ¹ are methyl groups.

  Moreover, a is a positive number of 1.95 to 2.05, preferably 1.98 to 2.02, more preferably 1.99 to 2.01.

  The degree of polymerization of the organopolysiloxane (A) is 2,000 or more (usually 2,000 to 100,000), preferably 3,000 to 80,000, more preferably 3,000 to 30,000, especially It is preferably 3,000 to 10,000, and is a so-called raw rubber (non-liquid) that does not have self-fluidity at room temperature (25 ° C., hereinafter the same). When the degree of polymerization is too small, problems such as roll adhesion occur when a compound is formed, and roll workability deteriorates. This degree of polymerization can be measured as a polystyrene-reduced weight average degree of polymerization by gel permeation chromatography (GPC) analysis using toluene or the like as a developing solvent.

The molecular structure of the organopolysiloxane as component (A) is not particularly limited as long as this condition is satisfied. Usually, the main chain is a diorganosiloxane unit (R ¹ ₂ SiO _2/2 , R ¹ is as described above. The same, the same shall apply hereinafter), preferably a linear diorganopolysiloxane having both ends of the molecular chain blocked with triorganosiloxy groups (R ¹ ₃ SiO _1/2 ), specifically Is a combination of one or more of dimethylsiloxane units, diethylsiloxane units, methylethylsiloxane units, diphenylsiloxane units, methylphenylsiloxane units, methyl-3,3,3-trifluoropropylsiloxane units, etc. Preferably, both ends of the molecular chain are dimethylvinylsiloxy, methyldivinylsiloxy, trivinylsiloxy. Those blocked with a xy group or the like are preferable, and preferably blocked with a siloxy group having at least one alkenyl group such as a vinyl group.

  (A) A component may be used individually by 1 type, or 2 or more types of mixtures from which molecular weight (polymerization degree) and molecular structure differ may be sufficient.

The component (B) has an average degree of polymerization of 2,000 or more and a total of at least 3 silicon atoms in one molecule at the molecular chain terminal and molecular chain side chain (that is, in the middle of the molecular chain or at the molecular chain non-terminal). A raw rubber organopolysiloxane containing an alkenyl group to be bonded at room temperature, preferably represented by the following average composition formula (II).
R ² _b SiO _{(4-b) / 2} (II)
(In the formula, R ² represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and b is a positive number of 1.95 to 2.05.)

In the above average composition formula (II), R ² represents the same or different unsubstituted or substituted monovalent hydrocarbon group, usually having 1 to 12 carbon atoms, particularly preferably having 1 to 8 carbon atoms. Are alkyl groups such as methyl, ethyl, propyl, butyl, hexyl and octyl, cycloalkyl such as cyclopentyl and cyclohexyl, alkenyl such as vinyl, allyl and propenyl, cyclo An aryl group such as an alkenyl group, a phenyl group or a tolyl group, an aralkyl group such as a benzyl group or a 2-phenylethyl group, or a part or all of the hydrogen atoms of these groups is a halogen atom such as fluorine or chlorine or a cyano group For example, chloromethyl group, trifluoropropyl group, cyanoethyl group, etc. substituted with A propyl group is preferable, and a methyl group and a vinyl group are particularly preferable.

  In particular, the (B) component organopolysiloxane has molecular chain terminals and molecular chain side chains (for example, monovalent hydrocarbon groups bonded to silicon atoms in the difunctional diorganopolysiloxane unit constituting the main chain). ) It is necessary to contain an alkenyl group bonded to at least 3 silicon atoms in total in one molecule, and preferably 0. 0 with respect to the number of silicon atoms in the molecule (or the number of siloxane units in the molecule). The alkenyl group contains 001 to 10 mol%, more preferably 0.001 to 5 mol%, and still more preferably 0.01 to 0.5 mol%. The alkenyl group is preferably a vinyl group or an allyl group, and more preferably a vinyl group.

Of the monovalent hydrocarbon groups represented by R ² in the molecule, 50 mol% or more is preferably a methyl group, more preferably 80 mol% or more is a methyl group, and other than alkenyl groups. More preferably, all R ² are methyl groups.

  Further, b is a positive number of 1.95 to 2.05, preferably 1.98 to 2.02, more preferably 1.99 to 2.01.

  The degree of polymerization of the organopolysiloxane (B) is 2,000 or more (usually 2,000 to 100,000), preferably 3,000 to 80,000, more preferably 3,000 to 30,000, especially It is preferably 3,000 to 10,000, and is a so-called raw rubber (non-liquid) that does not have self-fluidity at room temperature (25 ° C.). When the degree of polymerization is too small, problems such as roll adhesion occur when a compound is formed, and roll workability deteriorates. This degree of polymerization can be measured as a polystyrene-reduced weight average degree of polymerization by gel permeation chromatography (GPC) analysis using toluene or the like as a developing solvent.

The molecular structure of the organopolysiloxane (B) is not particularly limited as long as this condition is satisfied. Usually, the main chain is a diorganosiloxane unit (R ² ₂ SiO _2/2 , R ² is as described above. The same, the same shall apply hereinafter), and preferably a linear diorganopolysiloxane having both ends of the molecular chain blocked with triorganosiloxy groups (R ² ₃ SiO _1/2 ). The main chain is dimethylsiloxane unit / methylvinylsiloxane unit, dimethylsiloxane unit / divinylsiloxane unit, diethylsiloxane unit / ethylvinylsiloxane unit, diethylsiloxane unit / divinylsiloxane unit, methylethylsiloxane unit / methylvinylsiloxane unit, methyl Ethylsiloxane unit, divinylsiloxane unit, diphenylsiloxa Units, phenyl vinylsiloxane units, diphenylsiloxane units, divinylsiloxane units, diphenylsiloxane units, methylvinylsiloxane units, methylphenylsiloxane units, methylvinylsiloxane units, methylphenylsiloxane units, divinylsiloxane units, methyl-3,3 3-trifluoropropylsiloxane unit / methylvinylsiloxane unit, methyl-3,3,3-trifluoropropylsiloxane unit / divinylsiloxane unit, dimethylsiloxane unit / diphenylsiloxane unit / methylvinylsiloxane unit, dimethylsiloxane unit / methylphenyl Those consisting of siloxane units, methylvinylsiloxane units, etc. are preferred, and both ends of the molecular chain are dimethylvinylsiloxy groups, methyldivinylsiloxy. Groups are preferably those blocked with trivinylsiloxy group, which is preferably blocked with a siloxy group having at least one alkenyl group such as a vinyl group.

  (B) A component may be used individually by 1 type, or 2 or more types of mixtures from which molecular weight (polymerization degree) and a molecular structure differ may be sufficient.

  The blending amount of the components (A) and (B) is 3 parts by mass of the component (B), preferably 15 parts by mass of the component (B) to 97 parts by mass of the component (A). (A) 89 parts by weight of component (B) 11 parts by weight of component to (A) 97 parts by weight of component (B) 3 parts by weight of component, more preferably (A) 90 parts by weight of component (B) 10 of component It is in the range of 4 parts by mass of component (B) (100 parts by mass in total of component (A) and component (B)) to 96 parts by mass of component (A). When this blending amount satisfies such a range, a cured product having better elongation characteristics such as high elongation and low permanent elongation and mechanical characteristics such as low modulus, high flexibility and high tensile strength can be obtained.

  The addition reaction type curing agent of component (C) is a combination of an organohydrogenpolysiloxane (curing agent or crosslinking agent) and a hydrosilylation catalyst (curing catalyst), and silicon atom bonding in the organohydrogenpolysiloxane. A hydrogen atom (hereinafter sometimes referred to as a Si—H group) is crosslinked with an alkenyl group bonded to a silicon atom in the components (A) and (B) by a hydrosilylation addition reaction to cure the composition. It acts as a curing agent (crosslinking agent).

The hydrosilylation catalyst is a catalyst that causes an addition reaction between the alkenyl groups of the components (A) and (B) and the Si—H group of the organohydrogenpolysiloxane in the component (C).
Examples of the hydrosilylation catalyst include a platinum group metal catalyst. As the platinum group metal catalyst, a conventionally known catalyst can be used as an addition reaction curable silicone rubber composition catalyst. More specifically, for example, a platinum group metal simple substance and a compound thereof may be mentioned. Examples include fine platinum metal adsorbed on a carrier such as silica, alumina or silica gel, platinum chloride, chloroplatinic acid, chloroplatinic acid hexahydrate alcohol solution, palladium catalyst, rhodium catalyst, etc. Or a platinum compound is preferable.
A hydrosilylation catalyst may be used individually by 1 type, or may be used in combination of 2 or more type.

  The addition amount of the hydrosilylation catalyst may be an effective amount that can promote the above addition reaction, and preferably 1 ppm to 1 mass relative to the total mass of the components (A) and (B) in terms of the platinum group metal amount. %, And more preferably in the range of 10 to 500 ppm. When the addition amount is less than 1 ppm, the addition reaction may not be sufficiently promoted and curing may be insufficient. On the other hand, addition of more than 1% by mass has little influence on reactivity and is uneconomical. There is.

As organohydrogenpolysiloxane, if it contains 2 or more, preferably 3 to 200, more preferably 3 to 100, and still more preferably about 4 to 50 Si-H groups in one molecule, Any of a chain, a ring, a branched chain, and a three-dimensional network may be used, and a known organohydrogenpolysiloxane can be used as a crosslinking agent for an addition reaction curable silicone rubber composition. An organohydrogenpolysiloxane represented by the composition formula (III) can be used.
R ³ _p H _q SiO _{(4-pq) / 2} (III)

In the above average composition formula (III), R ³ represents an unsubstituted or substituted monovalent hydrocarbon group, which may be the same or different and excludes an aliphatic unsaturated bond. preferable. Usually, those having 1 to 12 carbon atoms, particularly 1 to 8 carbon atoms are preferred. Specifically, alkyl groups such as methyl group, ethyl group and propyl group, cycloalkyl groups such as cyclohexyl group, vinyl group, allyl group and butenyl. Groups, alkenyl groups such as hexenyl groups, aryl groups such as phenyl groups and tolyl groups, aralkyl groups such as benzyl groups, 2-phenylethyl groups and 2-phenylpropyl groups, and some or all of the hydrogen atoms of these groups Is a group substituted with a halogen atom or the like, for example, a 3,3,3-trifluoropropyl group.
Note that p and q are 0 ≦ p <3, preferably 1 ≦ p ≦ 2.2, 0 <q ≦ 3, preferably 0.002 ≦ q ≦ 1, 0 <p + q ≦ 3, preferably 1.002 ≦. It is a positive number satisfying p + q ≦ 3.

Specific examples of the organohydrogenpolysiloxane include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogencyclopolysiloxane, and methylhydrogensiloxane.・ Dimethylsiloxane cyclic copolymer, methylhydrogensiloxane, dimethylsiloxane, diphenylsiloxane cyclic copolymer, tris (dimethylhydrogensiloxy) methylsilane, tris (dimethylhydrogensiloxy) phenylsilane, trimethylsiloxy group-blocked methylhydro at both ends Genpolysiloxane, Trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, Dimethylpolysiloxy group-capped dimethylpolysiloxane Sun, both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenyl Siloxane / dimethylsiloxane copolymer, a copolymer comprising (CH ₃ ) ₂ HSiO _1/2 units and SiO _4/2 units, (CH ₃ ) ₂ HSiO _1/2 units and (CH ₃ ) ₃ SiO _{1 / A} copolymer comprising ₂ units and SiO _4/2 units, a copolymer comprising (CH ₃ ) ₂ HSiO _1/2 units, SiO _4/2 units and (C ₆ H ₅ ) SiO _3/2 units, In these exemplified compounds, those in which part or all of the methyl group is substituted with another alkyl group, phenyl group or the like can be mentioned.

（式中、ｋは２〜１０の整数、ｓ及びｔはそれぞれ０〜１０の整数である。） Specific examples of such organohydrogenpolysiloxanes include compounds having the following structural formula.

(In the formula, k is an integer of 2 to 10, and s and t are each an integer of 0 to 10.)

  The organohydrogenpolysiloxane may be used alone or in combination of two or more.

  The viscosity of the organohydrogenpolysiloxane at 25 ° C. is preferably about 0.1 to 1,000 mPa · s, more preferably about 0.5 to 500 mPa · s. In the present invention, the viscosity can be measured with a rotational viscometer (for example, BL type, BH type, BS type, cone plate type, etc.).

  As for the compounding quantity of the said organohydrogen polysiloxane, 0.1-40 mass parts is preferable with respect to a total of 100 mass parts of (A) and (B) component. The ratio of hydrogen atoms (Si-H groups) bonded to silicon atoms in the organohydrogenpolysiloxane is 0.5 to 20 in terms of molar ratio with respect to the total amount of alkenyl groups in the components (A) and (B). The range of (mol / mol) is appropriate, preferably 1-15 (mol / mol), more preferably 4-12 (mol / mol). If the molar ratio is less than 0.5, crosslinking may not be sufficient, and sufficient mechanical strength may not be obtained. If it exceeds 20, the surface tackiness may be increased.

  When the addition reaction type curing agent (component (C)) (combination of organohydrogenpolysiloxane and hydrosilylation catalyst) is used, the curing rate of the hydrosilylation addition reaction is adjusted in addition to the component (C). For the purpose, a reaction control agent may be further added to the composition. Specific examples of the reaction control agent include acetylene alcohol control agents such as ethynylcyclohexanol, tetracyclomethylvinylpolysiloxane, and the like.

Component (D) is reinforcing silica filled to obtain a silicone rubber composition having excellent mechanical strength. For this purpose, the specific surface area (BET adsorption method) is 50 m ² / g or more. Is preferably 100 to 450 m ² / g, more preferably 100 to 300 m ² / g. When the specific surface area is less than 50 m ² / g, the mechanical strength of the cured product is lowered, and when it exceeds 450 m ² / g, blending becomes difficult and the cured product may be discolored.

Examples of such reinforcing silica include fumed silica (fumed silica), precipitated silica (wet silica) and the like. These reinforcing silicas may be used as they are, but if necessary, What was surface-treated with organopolysiloxane, organopolysilazane, chlorosilane, alkoxysilane, or the like may be used.
(D) A component may be used individually by 1 type, or may be used in combination of 2 or more type.

  (D) The compounding quantity of a component is 1-40 mass parts with respect to a total of 100 mass parts of (A) and (B) component, It is preferable that it is 1-20 mass parts, It is 1-15 mass parts. It is particularly preferred. When the blending amount of the component (D) is less than 1 part by mass, a sufficient reinforcing effect cannot be obtained, and when it exceeds 40 parts by mass, the hardness of the cured product becomes high and sufficient flexibility cannot be obtained.

The component (E) has the following general formula (IV):
R ⁵ O (SiR ⁴ ₂ O) _m R ⁵ (IV)
(Wherein R ⁴ is the same or different unsubstituted or substituted monovalent hydrocarbon group, m is a positive number of 1 to 50, and R ⁵ is an alkyl group or a hydrogen atom.)
And an organosiloxane or an organosilane, or a mixture thereof, having an alkoxy group or a hydroxyl group (a silanol group, that is, a hydroxyl group bonded to a silicon atom) at the molecular chain terminal. The component (E) is used as a treating agent for treating the reinforcing silica of the component (D) and as a dispersant.

In general formula (IV), R ⁴ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms. Examples of the monovalent hydrocarbon group represented by R ⁴ include methyl groups, ethyl groups, propyl groups, butyl groups and other alkyl groups, cyclohexyl groups and other cycloalkyl groups, vinyl groups, allyl groups, butenyl groups, hexenyls. Alkenyl groups such as groups, aryl groups such as phenyl groups and tolyl groups, aralkyl groups such as β-phenylpropyl groups, or some or all of hydrogen atoms bonded to carbon atoms of these groups are halogen atoms, cyano groups, etc. And a chloromethyl group, a trifluoropropyl group, a cyanoethyl group and the like substituted with a methyl group, a vinyl group, and a phenyl group are preferable, and a methyl group and a vinyl group are particularly preferable. Further, in order to ensure compatibility with the organopolysiloxanes of the components (A) and (B), R ⁴ of the component (E) is the same as R ¹ and R ^{2 of the} components (A) and (B). It is preferable.

In the general formula (IV), R ⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms. Examples of R ⁵ include a hydrogen atom or an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group. In particular, a hydrogen atom, a methyl group, and an ethyl group are preferable.

  The degree of polymerization of component (E) (m in general formula (IV)) is 1 to 50, preferably 1 to 30, and more preferably 2 to 25. When the degree of polymerization (m) exceeds 50, the effect as a treating agent for treating the reinforcing silica of the component (D) decreases. This degree of polymerization can be measured as a weight average degree of polymerization in terms of polystyrene by gel permeation chromatography (GPC) analysis.

  Component (E) is blended in an amount of 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 0.5 to 10 parts by weight per 100 parts by weight of components (A) and (B). Part. When the blending amount of the component (E) is less than 0.1 parts by mass per 100 parts by mass of the components (A) and (B), kneading becomes difficult and plasticization is increased, and the amount exceeds 50 parts by mass. And the resulting silicone rubber composition becomes sticky.

  In addition to the above-described components, the silicone rubber composition of the present invention includes, as necessary, non-reinforcing silica such as quartz powder, crystalline silica, diatomaceous earth, and calcium carbonate, carbon such as acetylene black, furnace black, and channel black. Heat resistance improver such as black, colorant, bengara, cerium oxide, flame retardant improver such as platinum, titanium oxide, triazole compound, heat conductivity improver such as acid acceptor, alumina, boron nitride, release agent Further, an adhesion improver such as carbon functional silane may be added.

  The silicone rubber composition of the present invention is a non-liquid composition that does not have self-fluidity at room temperature, and can be used to knead each component uniformly under shear stress using a kneader such as a roll mill. Type silicone rubber composition, which can be obtained by uniformly mixing the above components using a kneading apparatus such as a two-roll mill, a Banbury mixer, or a dow mixer (kneader). It is desirable to blend the component (C) after mixing the components B), (D) and (E).

  The silicone rubber composition thus obtained can be cured by heating at the same time as molding, whereby a molded body made of a rubber-like elastic body (silicone rubber cured product) can be obtained.

The curing method may be a method in which sufficient heat is applied to accelerate the hydrosilylation reaction and vulcanize the silicone rubber composition. Although hardening temperature and hardening time are based also on a hardening method, Preferably they are 3 seconds-60 minutes at 80-400 degreeC, Most preferably, they are about 10 seconds-20 minutes at 100-200 degreeC.
Further, the molding method is not particularly limited, and for example, a molding method such as extrusion molding, compression molding, injection molding or the like can be adopted. Furthermore, secondary vulcanization (post cure) may be performed at 120 to 250 ° C. for about 1 to 10 hours as necessary.

  The silicone rubber composition of the present invention can be produced by mixing the above-mentioned components. This silicone rubber composition is cured by press curing at 120 ° C. for 1 hour after curing at 120 ° C. for 10 minutes. The hardness of the cured product (silicone rubber) obtained in accordance with JIS K6249 is 5-30, particularly 5-20. If the hardness is less than 5, the strength of the cured product is insufficient, and if it exceeds 30, the flexibility of the cured product is insufficient, so that it may not be suitably used for producing a medical balloon catheter. The above hardness range can be achieved by heating with the above-described curing method with the above-described components.

  Further, a cured product (silicone rubber) obtained by press curing this silicone rubber composition at 120 ° C. for 10 minutes and then post-curing at 150 ° C. for 1 hour is extended to 350% based on JIS K6301. It is preferable that the permanent elongation after holding for 24 hours and then removing the power and leaving it for 10 minutes is less than 15%, particularly less than 12%. In order to make permanent elongation into the said range, it can achieve by heating with the said hardening method by the structure of the said component, and can use it suitably for medical balloon catheter manufacture.

  Also, a 600% modulus of a cured product (silicone rubber) obtained by curing this silicone rubber composition by post-curing at 120 ° C. for 10 minutes and then post-curing at 150 ° C. for 1 hour was measured according to JIS K6249. Is preferably less than 1.5 MPa, particularly preferably less than 1 MPa, and the elongation at break is preferably 800% or more, particularly preferably 900% or more. The 600% modulus and elongation at break within the above ranges can be achieved by heating with the above-described curing method with the constitution of the above components, and can be suitably used for producing a medical balloon catheter.

  Silicone rubber, which is a cured product of the silicone rubber composition thus obtained, has a low modulus and little permanent elongation, has high extensibility and high flexibility, and is suitably used as a medical balloon catheter or the like. .

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, a polymerization degree shows the weight average polymerization degree of polystyrene conversion in GPC (gel permeation chromatography) analysis which used toluene as a developing solvent. “Phr” represents a part by mass per 100 parts by mass of the base rubber compound.

[Example 1]
(A) Both ends of the molecular chain are blocked with dimethylvinylsiloxy groups, and the average degree of polymerization containing a vinyl group only at the molecular chain ends is about 8,000. 96 parts by mass of dimethylpolysiloxane (molecular chain end vinyl group content 0.025 mol%), (B) both ends of the molecular chain are blocked with dimethylvinylsiloxy groups, and vinyl groups are attached to the molecular chain ends and molecular chain side chains. Containing dimethylsiloxane siloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer in the form of a raw rubber-like molecular chain at room temperature with an average degree of polymerization of about 8,000 (total vinyl group content of molecular chain terminal and molecular chain side chain 0 .150 mol%) 4 parts by mass, (D) BET specific surface area 130 m ² / g dry silica AEROSIL 130 (Nippon Aerosil Co., Ltd.) 10 Part (E) 1.5 parts by mass of hydroxydimethylpolysiloxane having both ends of a molecular chain having silanol groups at both ends and an average degree of polymerization of 3 is kneaded and heat treated at 165 ° C. for 2 hours. A rubber compound (1) was produced.

With respect to 100 parts by mass of this base rubber compound (1), (C) C-25A (platinum catalyst) 0.5 part by mass and C-25B (organohydrogenpolysiloxane) 2.0 are added as an addition reaction type curing agent. Mass parts (both manufactured by Shin-Etsu Chemical Co., Ltd.) were added with a two-roll mill and mixed uniformly, followed by press curing at 120 ° C. and 70 kgf / cm ² for 10 minutes, and then in an oven at 150 ° C. for 1 hour. Post-cure was performed to prepare a test sheet having a thickness of 2 mm. Using the prepared test sheet, various characteristics were measured according to the following measurement methods. The results are shown in Table 1. In addition, the molar ratio of the total of Si—H groups to the total of vinyl groups in the entire composition; SiH / SiVi is also shown in Table 1 (the same applies hereinafter).

[Measuring method]
[Hardness, tensile strength, elongation at break]
Using the above test sheet, hardness, tensile strength, and elongation at break were measured by a method according to JIS K6249.

[Permanent elongation]
The test sheet was stretched to 350% by the method according to JIS K6301, held for 24 hours, then de-forced and allowed to stand for 10 minutes to measure permanent elongation.

[600% modulus]
A 600% modulus was measured using the test sheet by a method according to JIS K6249.

[Roll adhesiveness]
The tackiness when kneading the base rubber compound with a two-roll mill was evaluated in two stages, with good workability (non-sticky) being rated as o and poor (sticky) being rated as x.

[Example 2]
The base rubber compound (2) was prepared in the same manner as in Example 1 except that the amount of component (A) used in Example 1 was 90 parts by mass and the amount of component (B) was 10 parts by mass. A similar evaluation was made. The results are shown in Table 1.

[Example 3]
The base rubber compound (D) used in Example 1 was prepared in the same manner as in Example 1 except that the dry surface-treated silica Musil 130A (manufactured by Shin-Etsu Chemical Co., Ltd.) having a BET specific surface area of 130 m ² / g was used. 3) was prepared and evaluated similarly. The results are shown in Table 1.

[Example 4]
The component (E) used in Example 1 was a molecular chain both-end hydroxydimethylpolysiloxane having silanol groups at both ends and an average degree of polymerization of 10, except that the blending amount was 4 parts by mass. Base rubber compound (4) was prepared by the same method as in No. 1, and the same evaluation was performed. The results are shown in Table 1.

[Comparative Example 1]
A base rubber compound (5) was prepared in the same manner as in Example 1 except that the amount of component (A) used in Example 1 was 100 parts by mass and the amount of component (B) was 0 parts by mass. A similar evaluation was made. The results are shown in Table 2.

[Comparative Example 2]
The base rubber compound (6) was prepared in the same manner as in Example 1 except that the amount of component (A) used in Example 1 was 30 parts by mass and the amount of component (B) was 70 parts by mass. A similar evaluation was made. The results are shown in Table 2.

[Comparative Example 3]
The blending amount of the component (A) used in Example 1 is 0 part by mass, the blending amount of the component (B) used in Example 1 is 80 parts by mass, and the other component (B) is both molecular chains. Dimethylsiloxane blocked with dimethylvinylsiloxy group at both ends of a raw rubber-like molecular chain having a terminal chain blocked with a dimethylvinylsiloxy group and containing a vinyl group at the molecular chain terminal and molecular chain side chain and an average degree of polymerization of about 8,000. A base rubber compound (7) in the same manner as in Example 1 except that 20 parts by mass of methyl vinyl siloxane copolymer (total vinyl group content of molecular chain terminal and molecular chain side chain: 0.5 mol%) was added. ) And the same evaluation was performed. The results are shown in Table 2.

[Comparative Example 4]
A base rubber compound (8) was prepared and evaluated in the same manner as in Example 1 except that the amount of component (D) used in Example 1 was 50 parts by mass. The results are shown in Table 2.

<Evaluation results>
The compositions prepared in Examples 1 to 4 satisfy the requirements of the present invention, such as elongation properties such as high elongation and low permanent elongation, mechanical properties such as low modulus, high flexibility and high tensile strength, and A cured product with better roll adhesion can be obtained.
On the other hand, the compositions prepared in Comparative Examples 1 to 4 did not satisfy the requirements of the present invention, and at least one of the above characteristics was inferior to those prepared in Examples.

Claims (4)

(A) 85 to 97 parts by mass of a raw rubber-like organopolysiloxane having an average polymerization degree of 2,000 or more and containing an alkenyl group bonded to at least two silicon atoms in one molecule only at the molecular chain terminal (B) A raw rubber-like organopolysiloxane having an average degree of polymerization of 2,000 or more and containing alkenyl groups bonded to at least three silicon atoms in one molecule at the molecular chain terminal and molecular chain side chain. ~ 3 parts by mass (however, the total of component (A) and component (B) is 100 parts by mass)
(C) Addition reaction type curing agent Effective amount (D) Reinforcing silica having specific surface area of 50 m ² / g or more by BET adsorption method (A), 1 to 40 parts by mass with respect to 100 parts by mass in total of components (B) (E) The following general formula (IV):
R ⁵ O (SiR ⁴ ₂ O) _m R ⁵ (IV)
(Wherein R ⁴ is the same or different unsubstituted or substituted monovalent hydrocarbon group, m is a positive number of 1 to 50, and R ⁵ is an alkyl group or a hydrogen atom.)
The organosiloxane or organosilane, or a mixture thereof represented by the formula (A), 100 parts by mass of the component (B), 0.1 to 50 parts by mass as a main component, at 120 ° C. for 10 minutes Addition-curing silicone for the production of medical balloon catheters that gives a cured product with a durometer A hardness meter of 5-30 measured according to JIS K6249 by post-curing at 150 ° C. for 1 hour after press curing Rubber composition.   After press curing at 120 ° C. for 10 minutes, post-curing at 150 ° C. for 1 hour, extending to 350% based on JIS K6301, holding for 24 hours, then removing the force and leaving for 10 minutes The addition-curable silicone rubber composition for producing a medical balloon catheter according to claim 1, which gives a cured product having an elongation of less than 15%.   3. A cured product having a 600% modulus measured in accordance with JIS K6249 of less than 1.5 MPa is obtained by performing a post cure at 150 ° C. for 1 hour after press curing at 120 ° C. for 10 minutes. An addition-curable silicone rubber composition for producing a medical balloon catheter.   The press-cure at 120 ° C for 10 minutes, followed by post-curing at 150 ° C for 1 hour, to give a cured product having an elongation at break measured according to JIS K6249 of 800% or more. 2. An addition-curable silicone rubber composition for producing a medical balloon catheter according to item 1.