JP6589572B2 - Condensation curable room temperature curable silicone rubber composition and electronic circuit - Google Patents

Description

  The present invention is preferably a condensation curable room temperature curable organopolysiloxane composition (condensation curable room temperature curable silicone rubber) having an organopolysiloxane having a hydrolyzable group and / or a hydroxyl group at the terminal as a main ingredient (base polymer). Condensation-curing room temperature that improves the low temperature viscoelastic properties of the cured silicone rubber obtained by curing the composition), and in particular provides a cured silicone rubber that exhibits stable rubber properties even at a low temperature of -50 ° C. or lower. The present invention relates to a curable silicone rubber composition and an electronic circuit sealed or adhesively fixed with a cured product (silicone rubber) of the composition.

  In the present invention, the silicone rubber (or cured silicone rubber) usually has a rubber hardness (Type A) as defined in JIS K 6249 at 25 ° C. of 5 or more, preferably 5 to 80, more preferably 10 to 70. Means an elastomeric cured product having mechanical strength and rubber elasticity (that is, a crosslinked product of organopolysiloxane), and the rubber hardness is 0 or less (that is, an effective rubber hardness value). It is essentially different from a so-called silicone gel (or a cured silicone gel) having a low hardness) and an extremely low crosslinking density.

  Condensation-curing room temperature curable (RTV) silicone rubber compositions that are crosslinked by moisture are easy to handle, and cured silicone rubbers obtained by curing the composition are excellent in weather resistance and electrical properties. It is used in various fields such as sealing materials for building materials, electrical / electronic fields, and adhesives for sealing materials for automotive electronic components.

  Especially for automotive applications, the cured silicone rubber is assumed to be used in a wide temperature range. Therefore, it is possible to reduce the change in the Young's modulus of the cured silicone rubber with temperature, even as a characteristic required for adhesives. It is starting to be requested.

On the other hand, dimethylsiloxane polymer, which is commonly used as the main component (base polymer) of silicone rubber, is a material with relatively excellent low-temperature characteristics, but due to the nature of the polymer, embrittlement phenomenon is observed at around -40 ° C. In the cured silicone rubber mainly composed of dimethylpolysiloxane, the Young's modulus at a low temperature around -40 ° C. was significantly increased, and it was difficult to expand the use in the above-mentioned in-vehicle use. Polymers have become necessary.
In addition, the following literature is mentioned as a prior art relevant to this invention.

Japanese Patent Laid-Open No. 61-021157 JP-A-63-083167 JP 63-099236 A

  The present invention has been made in view of the above circumstances, and is a condensation curable room temperature curable silicone rubber composition that provides a cured silicone rubber exhibiting stable viscoelastic properties even in an extremely low temperature region of −50 ° C. or lower, and the composition. An object of the present invention is to provide an electronic circuit or the like that is sealed or bonded and fixed with a cured product (silicone rubber).

  As a result of intensive studies to achieve the above object, the inventors of the present invention have developed a condensation-curable organopolysiloxane having a hydrolyzable group and / or a hydroxyl group and a specific amount of an aromatic monovalent hydrocarbon group in the molecule. A condensation-curing room temperature curable silicone rubber composition that gives a cured silicone rubber that exhibits stable viscoelastic properties even in an extremely low temperature region of −50 ° C. or lower by being used as a base polymer of a room temperature curable silicone rubber composition of As a result, the inventors have found that the present invention can be obtained and have made the present invention.

（式中、Ｒ³は炭素数１〜１０の非置換又はハロゲン置換一価炭化水素基であり、Ｒ⁴は独立に炭素数１〜１０の非置換の一価炭化水素基であり、ｄは３又は４である。）
で示されるアミノ基非含有の加水分解性オルガノシラン及び／又はその部分加水分解縮合物：０．２〜３０質量部、
（Ｃ）下記一般式（３）で示されるアミノ基含有加水分解性オルガノシラン及び／又はその部分加水分解物：０．１〜１０質量部、

（式中、Ｒ⁷は芳香環を含む炭素数７〜１０の二価炭化水素基であり、Ｒ⁸は炭素数１〜１０の二価炭化水素基であり、Ｒ⁹及びＲ¹⁰はそれぞれ独立に炭素数１〜１０の非置換又はハロゲン置換一価炭化水素基であり、ｇは２又は３である。但し、１級及び２級アミンの少なくとも一方はＲ⁷の芳香環に直結していない。）
（Ｄ）硬化触媒：０．１〜２０質量部、
（Ｅ）炭酸カルシウムから選ばれる少なくとも１種の無機充填剤：５〜２００質量部、
（Ｆ）分子鎖両末端トリメチルシロキシ基封鎖ジメチルポリシロキサン、分子鎖両末端トリメチルシロキシ基封鎖ジメチルシロキサン・ジフェニルシロキサン共重合体、及び分子鎖両末端トリメチルシロキシ基封鎖ジメチルシロキサン・メチルフェニルシロキサン共重合体から選ばれる非反応性ジメチルシリコーンオイル又はメチルフェニルシリコーンオイル：２〜７０質量部
を含有し、２５℃、加振周波数１Ｈｚで測定したヤング率が１．０×１０⁴Ｐａ以上であり、−５０℃、加振周波数１Ｈｚで測定したヤング率が１．０×１０⁸Ｐａ以下であるシリコーンゴム硬化物を与えるものである縮合硬化型室温硬化性シリコーンゴム組成物。
〔２〕
（Ｅ）成分の配合量が、（Ａ）成分１００質量部に対して５〜１４２．９質量部である〔１〕記載の縮合硬化型室温硬化性シリコーンゴム組成物。
〔３〕
（Ｆ）成分の配合量が、（Ａ）成分１００質量部に対して２〜５７．１質量部である〔１〕又は〔２〕記載の縮合硬化型室温硬化性シリコーンゴム組成物。
〔４〕
〔１〕〜〔３〕のいずれかに記載の縮合硬化型室温硬化性シリコーンゴム組成物の硬化物でシール又は接着固定された電子回路。 That is, the present invention provides the following condensation curable room temperature curable silicone rubber composition and an electronic circuit sealed or adhesively fixed with a cured product (silicone rubber) of the composition.
[1]
(A) The following average composition formula (1)
R _a R ¹ _b (R ² O) _c SiO _{(4-abc) / 2} (1)
Wherein R is independently an unsubstituted or substituted monovalent hydrocarbon group not containing an aromatic group, R ¹ is independently an unsubstituted or substituted aromatic monovalent hydrocarbon group, and R ² is Independently an unsubstituted or substituted monovalent hydrocarbon group or hydrogen atom that does not contain an aromatic group, a is a number from 1.7 to 2.2, b is a number from 0.02 to 0.1, c is a number from 0.0001 to 0.2, and a + b + c is a number satisfying 1.9 to 2.4, provided that the silicon atom at the end of the molecular chain is linked to the silicon atom adjacent to the silicon atom. The oxygen atom (O) may be substituted with the following divalent linking group —R′—.)
The molecule has a hydrolyzable group and / or hydroxyl group bonded to at least one silicon atom in the molecule, and the terminal is -R'-SiR " ₃ (wherein R 'is an oxygen atom or a carbon number of 1 And R ″ is independently R, R ¹ or OR ² , and at least one of the three R ″ is OR ^2. R, R ¹ and R ² are as described above. And 100 parts by mass of the organopolysiloxane blocked with
(B) The following general formula (2)

Wherein R ³ is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R ⁴ is independently an unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and d is 3 or 4)
An amino group-free hydrolyzable organosilane and / or a partial hydrolysis condensate thereof represented by: 0.2 to 30 parts by mass ,
(C) Amino group-containing hydrolyzable organosilane represented by the following general formula (3) and / or a partial hydrolyzate thereof : 0.1 to 10 parts by mass ,

(In the formula, R ⁷ is a C 7-10 divalent hydrocarbon group containing an aromatic ring, R ⁸ is a C 1-10 divalent hydrocarbon group, and R ⁹ and R ¹⁰ are each independent. Is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and g is 2 or 3. However, at least one of the primary and secondary amines is not directly connected to the aromatic ring of R ^7. .)
(D) Curing catalyst : 0.1 to 20 parts by mass ,
(E) at least one inorganic filler selected from calcium carbonate acid: 5 to 200 parts by weight,
(F) Molecular chain both ends trimethylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / diphenylsiloxane copolymer, and molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer A non-reactive dimethyl silicone oil or methylphenyl silicone oil selected from: 2 to 70 parts by mass , and a Young's modulus measured at 25 ° C. and an excitation frequency of 1 Hz is 1.0 × 10 ⁴ Pa or more. A condensation curable room temperature curable silicone rubber composition which gives a cured silicone rubber having a Young's modulus of 1.0 × 10 ⁸ Pa or less measured at −50 ° C. and an excitation frequency of 1 Hz.
[2]
(E) Condensation hardening room temperature curable silicone rubber composition as described in [1] whose compounding quantity of component is 5-142.9 mass parts with respect to 100 mass parts of (A) component.
[3]
(F) The condensation curable room temperature curable silicone rubber composition according to [1] or [2], wherein the compounding amount of component is 2 to 57.1 parts by mass with respect to 100 parts by mass of component (A).
[4]
An electronic circuit sealed or adhesively fixed with a cured product of the condensation curable room temperature curable silicone rubber composition according to any one of [1] to [3].

  The condensation curable room temperature curable silicone rubber composition of the present invention is a silicone rubber cured product obtained by condensation curing (crosslinking) with atmospheric moisture at room temperature (20 ° C. ± 15 ° C.). The cured product exhibits good adhesion to a substrate such as a resin or metal of the adherend. Further, even when the obtained cured silicone rubber is stored for a long period of time at a low temperature (particularly at an extremely low temperature of −50 ° C. or lower), there is almost no change in Young's modulus and a stable viscoelastic property is exhibited. Therefore, it can be suitably used for sealing or adhesive fixing of on-vehicle electronic components and railway vehicle electronic components.

  The condensation curable room temperature curable silicone rubber composition of the present invention contains the above components (A) to (D) as essential components, and may contain other optional components. Hereinafter, each component will be described in detail. In the present specification, the viscosity is a measured value at 25 ° C.

[Component (A)] Hydrolyzable group and / or hydroxyl group-containing organopolysiloxane Bonded to at least one silicon atom in the molecule which is component (A) of the condensation curable room temperature curable silicone rubber composition of the present invention. The organopolysiloxane having a hydrolyzable group and / or a hydroxyl group is a component that becomes the main component (base polymer) of the composition. This (A) component is the following average composition formula (1)
R _a R ¹ _b (R ² O) _c SiO _{(4-abc) / 2} (1)
Wherein R is independently an unsubstituted or substituted monovalent hydrocarbon group not containing an aromatic group, R ¹ is independently an unsubstituted or substituted aromatic monovalent hydrocarbon group, and R ² is Independently an unsubstituted or substituted monovalent hydrocarbon group or hydrogen atom that does not contain an aromatic group, a is a number from 1.7 to 2.2, b is a number from 0.01 to 0.2, c is a number from 0.0001 to 0.2, and a + b + c is a number satisfying 1.9 to 2.4, provided that the silicon atom at the end of the molecular chain is linked to the silicon atom adjacent to the silicon atom. The oxygen atom (O) may be substituted with the following divalent linking group —R′—.)
In one molecule, a hydrolyzable group bonded to a silicon atom represented as an R ² O group (that is, an organooxy group not containing an aromatic group) and / or a hydroxyl group bonded to a silicon atom (silanol group) ) And the terminal is —R′—SiR ″ ₃ (wherein R ′ is an oxygen atom or an alkylene group having 1 to 5 carbon atoms, and R ″ is independently R, R ¹ or OR ^2). And at least one of the three R ″ is OR ^2. R, R ¹ and R ² are as described above).

The hydrolyzable group and / or hydroxyl group (R ² O group) needs to have at least one in one molecule, preferably 2 to 50, more preferably 2 to 20 in one molecule. preferable. These hydrolyzable groups and / or hydroxyl groups may be bonded to the silicon atom at the molecular chain end, or may be bonded to the silicon atom at the non-terminal end of the molecular chain (that is, other than both ends of the molecular chain), or However, at least one of them may be bonded to each end of the molecular chain.

  In the above formula (1), R usually represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 6 and not containing an aromatic group. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl and the like. An alkenyl group such as a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group or an isobutenyl group; Examples thereof include a methyl group and a 3,3,3-trifluoropropyl group. From the viewpoint of ease of synthesis, a methyl group and a 3,3,3-trifluoropropyl group are preferable.

R ¹ in the above formula (1) usually represents an unsubstituted or substituted aromatic monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms. Specific examples thereof include aryl groups such as phenyl group and tolyl group; aralkyl groups such as benzyl group and phenylethyl group, and some or all of hydrogen atoms of these groups are substituted with halogen atoms such as fluorine and chlorine. Moreover, although a chlorophenyl group etc. are mentioned, a phenyl group is preferable from viewpoints of the ease of a synthesis | combination.

R ² in the above formula (1) is usually a hydrogen group (hydrogen atom) or an unsubstituted or substituted monovalent carbon atom having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, which does not have an aromatic group. Represents a hydrogen group. Specific examples thereof include hydrogen group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, octyl group, decyl group, dodecyl group. Alkyl groups such as vinyl groups, allyl groups, propenyl groups, isopropenyl groups, butenyl groups, isobutenyl groups and other alkenyl groups, and some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine and chlorine And a chloromethyl group, 3,3,3-trifluoropropyl group, etc., and from the viewpoint of ease of synthesis, a hydrogen group or a methyl group is preferable.

In said formula (1), a is a number of 1.7-2.2, Preferably it is a number of 1.8-2.1. b is a number of 0.01 to 0.2, preferably 0.02 to 0.1. c is a number from 0.0001 to 0.2, preferably from 0.0002 to 0.1. Moreover, a + b + c is a number satisfying 1.9 to 2.4, and preferably a number satisfying 1.95 to 2.05.
When the value of b is smaller than 0.01 or larger than 0.2, the resulting silicone rubber cured product has a Young's modulus at −50 ° C. exceeding 1.0 × 10 ⁸ Pa, and the low temperature characteristics are deteriorated.

The organopolysiloxane of component (A) has its ends blocked with -R'-SiR " ₃ .
Here, the divalent linking group R ′ is an oxygen atom or an alkylene group such as a methylene group having 1 to 5 carbon atoms, an ethylene group or a propylene group, and among them, an oxygen atom or an ethylene group is preferable.
R ″ is independently R, R ¹ or OR ² , but at least one of the three R ″ on each silyl group at the end of the molecular chain is OR ² . R, R ¹ and R ² are as described above. R ″ is preferably a methyl group, a methoxy group or a hydroxyl group.

The molecular structure of the organopolysiloxane of the component (A) is not particularly limited, but is linear; a part of the molecular chain includes RSiO _3/2 units, R ¹ SiO _3/2 units, SiO ₂ units (in the formula, The groups represented by R and R ¹ are as defined above.) And the like may be any of branched, cyclic, three-dimensional network (resinous), etc. It is a linear diorganopolysiloxane composed of repeating diorganosiloxane units and having both ends of the molecular chain blocked with diorgano (hydroxy) siloxy groups and / or diorgano (organoxy) siloxy groups.

(A) The viscosity (25 degreeC) of the organopolysiloxane of a component becomes like this. Preferably it is 100-1,000,000 mPa * s, More preferably, it is 1,000-500,000 mPa * s. When this viscosity is 100 to 1,000,000 mPa · s, the resulting cured silicone rubber is superior in strength, fluidity and workability. The viscosity can be measured with a rotational viscometer (for example, BL type, BH type, BS type, cone plate type, rheometer, etc.).
When the component (A) is a linear organopolysiloxane, the degree of polymerization of the organopolysiloxane giving the above viscosity range (that is, the number of repeating diorganosiloxane units constituting the main chain) is, for example, 100 ˜2,000, preferably 200˜1,500, more preferably about 300˜1,300. The degree of polymerization or molecular weight can be determined, for example, as the number average degree of polymerization (or number average molecular weight) in terms of polystyrene in gel permeation chromatography (GPC) analysis using toluene or the like as a developing solvent.

（式中、Ｒ⁵は独立に芳香族基を含まない非置換もしくは置換の一価炭化水素基、アルコキシ基又は水酸基を表し、但し、Ｒ⁵の少なくとも１個はアルコキシ基又は水酸基であり、Ｒ⁶は独立に非置換又は置換の芳香族一価炭化水素基であり、Ｒ’は上記と同じであり、ｅは１００〜１，８００の整数であり、ｆは１〜５００の整数である。但し、（（Ｒ⁵）₂ＳｉＯ）単位と（（Ｒ⁶）₂ＳｉＯ）単位との配列はランダムであり、かつ、分子中のケイ素原子数に対するＲ⁶基数の比率は０．０１〜０．２である。） Examples of the organopolysiloxane of the component (A) that satisfies the above requirements include those represented by the following general formula (1a).

(Wherein R ⁵ independently represents an unsubstituted or substituted monovalent hydrocarbon group, alkoxy group or hydroxyl group not containing an aromatic group, provided that at least one of R ⁵ is an alkoxy group or a hydroxyl group; ⁶ is independently an unsubstituted or substituted aromatic monovalent hydrocarbon group, R ′ is the same as described above, e is an integer of 100 to 1,800, and f is an integer of 1 to 500. However, the arrangement of ((R ⁵ ) ₂ SiO) units and ((R ⁶ ) ₂ SiO) units is random, and the ratio of the number of R ⁶ groups to the number of silicon atoms in the molecule is 0.01-0. 2)

In this formula (1a), R ⁵ is an unsubstituted or substituted monovalent hydrocarbon group, alkoxy group or hydroxyl group not containing an aromatic group, and an unsubstituted or substituted monovalent hydrocarbon group not containing an aromatic group Is the same as defined by R in the average composition formula (1), and the carbon number, specific examples, and the like are also the same. Examples of the alkoxy group include those having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. R ⁵ is preferably a methyl group, a methoxy group, or a hydroxyl group.
Moreover, the unsubstituted or substituted aromatic monovalent hydrocarbon group represented by R ⁶ is the same as that defined by R ¹ in the average composition formula (1), and the carbon number, specific examples, and the like are also the same. It is.
Further, e is preferably an integer of 300 to 1,500, more preferably 400 to 1,300, and f is preferably an integer of 4 to 400, more preferably 10 to 300.

（式中、Ｒ³は炭素数１〜１０の非置換又はハロゲン置換一価炭化水素基であり、Ｒ⁴は独立に炭素数１〜１０の非置換の一価炭化水素基であり、ｄは３又は４である。） [Component (B)]
The component (B) is a hydrolyzable organosilane containing no amino group and / or a partial hydrolysis condensate thereof represented by the following general formula (2), and the terminal blocking agent and the crosslinking agent of the component (A) It acts as.

Wherein R ³ is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R ⁴ is independently an unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and d is 3 or 4)

In the formula, R ³ is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, or a propyl group; a cyclohexyl group, etc. A cyclic alkyl group of: an alkenyl group such as a vinyl group or an allyl group; an aryl group such as a phenyl group or a tolyl group; and a group in which the hydrogen atom of these groups is partially substituted with a halogen atom, such as 3, 3, And a 3-trifluoropropyl group. Among these, a methyl group, an ethyl group, a propyl group, a vinyl group, a phenyl group, and a 3,3,3-trifluoropropyl group are preferable, and a methyl group, a vinyl group, and a phenyl group are more preferable. R ⁴ is independently an unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and examples include those obtained by removing halogen-substituted monovalent hydrocarbon groups from those exemplified as R ^3. , A methyl group and an ethyl group are preferable, and a methyl group is particularly preferable. In R ³ and R ⁴ , R ³ and R ⁴ may be the same or different, and R ³ and R ⁴ may be the same or different.
D is 3 or 4.
Here, the partially hydrolyzed condensate means two or more in the molecule, which is produced by partially hydrolyzing and condensing an amino group-free hydrolyzable organosilane represented by the general formula (2), preferably Means a hydrolyzable organosiloxane oligomer having three or more residual hydrolyzable groups (R ⁴ O groups).

  Specific examples of the component (B) include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, and other alkoxysilanes, and these Examples thereof include partial hydrolysis condensates of silane. In these, tetramethoxysilane, methyltrimethoxysilane, and these partial hydrolysis-condensation products are preferable.

  The amount of component (B) is preferably 0.2 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, particularly preferably 1 to 15 parts by weight, and more preferably 100 parts by weight of component (A). Preferably the range of 5-12 mass parts is desirable. When the blending amount of the component (B) is too small, the storage stability may be lowered, and when the blending amount of the component (B) is too large, the obtained cured product is likely to deteriorate in mechanical properties and the curing rate is also high. There may be a drawback such as slowness.

[Component (C)]
The (C) component amino group-containing hydrolyzable organosilane and / or its partial hydrolyzate has a hydrolyzable group such as a silanol group and / or an alkoxy group (preferably at the end) as the component (A). It has an important effect as an endocapping catalyst for organopolysiloxane and an adhesion-imparting agent. As a suitable component (C), an amino group-containing silane coupling agent (that is, amino as a carbon functional group) Examples include hydrolyzable organosilanes such as alkoxysilanes having a monovalent hydrocarbon group in the molecule and / or partial hydrolysates thereof, and particularly include amino groups represented by the following general formula (3) Hydrolyzable organosilanes and / or partial hydrolysates thereof are preferred.

（式中、Ｒ⁷は芳香環を含む炭素数７〜１０の二価炭化水素基であり、Ｒ⁸は炭素数１〜１０の二価炭化水素基であり、Ｒ⁹及びＲ¹⁰はそれぞれ独立に炭素数１〜１０の非置換又はハロゲン置換一価炭化水素基であり、ｇは２又は３である。但し、１級及び２級アミンの少なくとも一方はＲ⁷の芳香環に直結していない。）

(In the formula, R ⁷ is a C 7-10 divalent hydrocarbon group containing an aromatic ring, R ⁸ is a C 1-10 divalent hydrocarbon group, and R ⁹ and R ¹⁰ are each independent. Is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and g is 2 or 3. However, at least one of the primary and secondary amines is not directly connected to the aromatic ring of R ^7. .)

  This amino group-containing hydrolyzable organosilane has a structure containing an aromatic ring between a primary amine and a secondary amine, and at least one of which is not directly connected to the aromatic ring. It is described in the gazette.

In the formula (3), R ⁷ is a divalent hydrocarbon group having 7 to 10 carbon atoms including an aromatic ring, and is preferably a group in which a phenylene group and an alkylene group are bonded, for example, the following formulas (4) to (12 ).
—CH ₂ —C ₆ H ₄ — (4)
—CH ₂ —C ₆ H ₄ —CH ₂ — (5)
—CH ₂ —C ₆ H ₄ —CH ₂ —CH ₂ — (6)
—CH ₂ —C ₆ H ₄ —CH ₂ —CH ₂ —CH ₂ — (7)
—CH ₂ —CH ₂ —C ₆ H ₄ — (8)
—CH ₂ —CH ₂ —C ₆ H ₄ —CH ₂ — (9)
—CH ₂ —CH ₂ —C ₆ H ₄ —CH ₂ —CH ₂ — (10)
—CH ₂ —CH ₂ —CH ₂ —C ₆ H ₄ — (11)
—CH ₂ —CH ₂ —CH ₂ —C ₆ H ₄ —CH ₂ — (12)
Of these, a group represented by the formula (5) is particularly preferable.
The orientation of the alkylene group bonded to the phenylene group may be any of ortho, meta, and para positions. Particularly preferred is the meta position.

R ⁸ is a divalent hydrocarbon group having 1 to 10 carbon atoms, such as methylene group, ethylene group, propylene group, tetramethylene group, hexamethylene group, octamethylene group, decamethylene group, 2-methylpropylene group, etc. Examples include an alkylene group, an arylene group such as a phenylene group, and a group in which the alkylene group and the arylene group are bonded, and an alkylene group having 1 to 4 carbon atoms is preferable.
R ⁹ and R ¹⁰ are each independently an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and examples are the same as those exemplified for R ³ in the formula (2). Can do. R ⁹ is preferably a methyl group, vinyl group or phenyl group, more preferably a methyl group, and R ¹⁰ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group. .

  The amount of component (C) is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of component (A). It is. When the blending amount of the component (C) is too small, the terminal blocking ratio may be lowered or the adhesiveness may be lowered. If the amount is too large, it may be disadvantageous in price, or the storage stability of the composition may be lowered.

[(D) component]
The curing catalyst of component (D) is not particularly limited as long as it has a condensation catalytic action, but in applications where it is not preferable to use an organic tin compound catalyst environmentally, it is preferably other than an organic tin compound. . Specific examples of such a curing catalyst include tetraisopropoxy titanium, tetra-n-butoxy titanium, tetrakis (2-ethylhexoxy) titanium, isopropoxy titanium bis (ethyl acetoacetate), isopropoxy bis (acetylacetonate) titanium. , Titanate or titanium chelate compounds such as titanium isopropoxyoctylene glycol; aluminum isopropylate, aluminum sec-butylate, aluminum ethylate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum Aluminum alcoholate or aluminum chelate compound such as diisopropylate; tetramethylguanidylpropyltrimeth Silanes or siloxanes containing guanidyl groups such as silane, tetramethylguanidylpropylmethyldimethoxysilane, tetramethylguanidylpropyltris (trimethylsiloxy) silane; conventional octylate and other acidic or basic catalysts Known catalysts are exemplified. Among these, an organic titanium compound is preferable, a titanium chelate compound is particularly preferable, and isopropoxy titanium bis (ethyl acetoacetate) and isopropoxy bis (acetylacetonate) titanium are particularly preferable.
As the curing catalyst for component (D), one kind may be used alone, or two or more kinds may be used as a mixture.

  The amount of component (D) is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 15 parts by mass, and particularly preferably 1 to 15 parts by mass with respect to 100 parts by mass of component (A). . If the blending amount of component (D) is too small, sufficient crosslinkability may not be obtained, and if it is too large, disadvantages such as a disadvantage in price or a decrease in curing speed may occur. .

[Other ingredients]
Further, in the condensation curable room temperature curable silicone rubber composition of the present invention, inorganic fillers, additives and the like may be blended as optional components in addition to the above components as long as the object of the present invention is not impaired.
Examples of inorganic fillers include silica-based fillers such as pulverized silica, fumed silica (dry silica), wet silica (precipitated silica), and crystalline silica (quartz powder), as well as aluminum hydroxide, alumina, boehmite, and water. Examples include magnesium oxide, magnesium oxide, calcium hydroxide, calcium carbonate, zinc carbonate, basic zinc carbonate, zinc oxide, titanium oxide, carbon black, glass beads, glass balloons, resin beads, and resin balloons. They may be used alone or in combination of two or more. Of these, fumed silica and calcium carbonate are preferred. Even if these inorganic fillers are not surface-treated, they may be surface-treated with a known treating agent such as chlorosilane, alkoxysilane, silazane, organopolysiloxane, fatty acid, and fatty acid derivative.
When blending the inorganic filler, the blending amount is preferably 0 to 300 parts by mass, more preferably 5 to 200 parts by mass with respect to 100 parts by mass of the organopolysiloxane of the component (A).

Examples of additives include polyethers as wetters and thixotropy improvers, non-reactive dimethyl silicone oils and methylphenyl silicone oils as plasticizers (for example, trimethylsiloxy group-capped dimethylpolysiloxanes at both molecular chain ends, Terminal trimethylsiloxy group-blocked dimethylsiloxane / diphenylsiloxane copolymer, molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer), isoparaffin, trimethylsiloxy unit [(CH ₃ ) as a crosslinking density improver ₃ SiO _1/2 units] and reticulated polysiloxanes composed of SiO ₂ units. Among these, non-reactive dimethyl silicone oil or methylphenyl silicone oil as a plasticizer can be suitably used for adjustment of hardness and adjustment of workability. It is preferable that it is 1-100 mass parts with respect to 100 mass parts of organopolysiloxane of A) component, More preferably, it is 2-70 mass parts.

Furthermore, if necessary, colorants such as pigments, dyes, fluorescent brighteners, fungicides, antibacterial agents, non-reactive phenyl silicone oils as bleed oil, fluorosilicone oils, organic liquids incompatible with silicones A solvent such as a surface modifier such as toluene, xylene, solvent volatile oil, cyclohexane, methylcyclohexane, and low boiling point isoparaffin may be added.
These components may be blended in any step of the production method of the present invention.

In the method for producing the condensation curable room temperature curable silicone rubber composition of the present invention, before mixing the component (D) in each of the components described above, a part or all of the component (A) and the component (B) are preliminarily mixed. More preferably, (A) component and (B) component are mixed, and then (C) component is mixed, or (A) component, (B) component, and (C) component are mixed simultaneously. To do. Or after mixing (A) component and (B) component beforehand, you may mix (C) component and (D) component simultaneously.
Here, mixing of (A) component, (B) component, and (C) component, or (A) component and (B) component is room temperature (usually 0-40 degreeC, under substantially anhydrous conditions). The time is preferably 10 to 30 ° C., and the time is usually about 10 minutes to 5 hours, preferably about 20 minutes to 3 hours. Further, the mixing is preferably performed under normal pressure or under pressure.
Then, (A) component, the mixture of (B) component, and (C) component, and (D) component are mixed. Or the mixture of (A) component and (B) component, (C) component, and (D) component are mixed. The mixing in this case may be performed at room temperature (20 ° C. ± 15 ° C.), but may be heated as necessary. The mixing time may be a time sufficient for the above components to be uniform, and is usually about 5 minutes to 2 hours, preferably about 10 minutes to 1 hour. Further, the mixing is preferably performed under normal pressure or reduced pressure.

The component (B) is preferably partly premixed with the component (A), component (C), or component (A), and the remainder is mixed after premixing, but in this case, it is used for premixing ( The component (B) may be an amount sufficient to block the end of the component (A).
Moreover, when mix | blending components other than the said (A)-(D) component, although you may mix | blend in which process, it is desirable to mix before mixing (D) component.

  The resulting condensation curable room temperature curable silicone rubber composition can be stored in an atmosphere avoiding moisture, and is allowed to stand at room temperature, usually in the presence of moisture in the air for 5 minutes to 1 week. Cures to a degree.

The cured product of the condensation curable room temperature curable silicone rubber composition of the present invention has a Young's modulus of 1.0 × 10 ⁴ Pa or more, preferably 5.0 × 10 ^{4 to} 5 at 25 ° C. and an excitation frequency of 1 Hz. 0.0 × 10 ⁷ Pa, and Young's modulus measured at −50 ° C. and an excitation frequency of 1 Hz is 1.0 × 10 ⁸ Pa or less, preferably 1.0 × 10 ^{5 to} 6.0 × 10 ⁷ Pa. . The Young's modulus can be measured with a normal viscoelasticity measuring machine.

  The condensation curable room temperature curable silicone rubber composition of the present invention is useful for sealing or bonding and fixing electronic circuits for in-vehicle use and railway vehicles.

  EXAMPLES Hereinafter, examples and comparative examples for specifically explaining the present invention will be shown, but the present invention is not limited to the following examples.

で表される２５℃における粘度が３００Ｐａ・ｓの両末端シラノール基封鎖ジメチルポリシロキサン・ジフェニルポリシロキサン共重合体３５質量部、下記式（ｂ）

で表される２５℃における粘度が１００ｍＰａ・ｓの両末端トリメチルシリル基封鎖ジメチルポリシロキサン・ジフェニルポリシロキサン共重合体２０質量部、コロイド質炭酸カルシウム４０質量部、重質炭酸カルシウム１０質量部を減圧下、６０分混合した。
次に、メチルトリメトキシシランの部分加水分解物４質量部を添加し、減圧下、４０分間混合した後、チタンジイソプロポキシビス（エチルアセトアセテート）４質量部、及び下記式（ｃ）

で表されるアミノ基含有シラン１質量部を減圧下にて３０分混合し、組成物１を得た。 [Example 1]
The following formula (a)

Represented by the following formula (b): 35 parts by mass of a silanol group-blocked dimethylpolysiloxane / diphenylpolysiloxane copolymer having a viscosity of 300 Pa · s at 25 ° C.

20 parts by mass of a dimethylpolysiloxane-diphenylpolysiloxane copolymer blocked with trimethylsilyl groups at both ends with a viscosity of 100 mPa · s at 25 ° C. represented by 40 parts by mass of colloidal calcium carbonate and 10 parts by mass of heavy calcium carbonate under reduced pressure. For 60 minutes.
Next, 4 parts by mass of a partial hydrolyzate of methyltrimethoxysilane was added and mixed under reduced pressure for 40 minutes, and then 4 parts by mass of titanium diisopropoxybis (ethylacetoacetate) and the following formula (c)

1 part by mass of an amino group-containing silane represented by the formula (1) was mixed under reduced pressure for 30 minutes to obtain a composition 1.

で表される２５℃における粘度が２５０Ｐａ・ｓである両末端トリメトキシシルエチレン基封鎖ジメチルポリシロキサン・ジフェニルポリシロキサン共重合体３５質量部を用いる以外は同様にして、組成物２を得た。 [Example 2]
In Example 1, instead of the dimethylpolysiloxane / diphenylpolysiloxane copolymer blocked with both ends silanol groups represented by the formula (a), the following formula (d)

A composition 2 was obtained in the same manner except that 35 parts by mass of a trimethoxysilethylene group-blocked dimethylpolysiloxane / diphenylpolysiloxane copolymer having a viscosity at 25 ° C.

で表される２５℃における粘度が５０Ｐａ・ｓの両末端トリメトキシシリル基封鎖ジメチルポリシロキサン・ジフェニルポリシロキサン共重合体３５質量部を用いる以外は同様にして、組成物３を得た。 [Example 3]
In Example 1, instead of the dimethylpolysiloxane / diphenylpolysiloxane copolymer blocked with both ends silanol groups represented by the formula (a), the following formula (e):

A composition 3 was obtained in the same manner except that 35 parts by weight of a trimethoxysilyl group-blocked dimethylpolysiloxane / diphenylpolysiloxane copolymer having a viscosity at 25 ° C.

で表される２５℃における粘度が２８０Ｐａ・ｓの両末端シラノール基封鎖ジメチルポリシロキサン３５質量部を用いる以外は同様にして、組成物４を得た。 [Comparative Example 1]
In Example 1, instead of the dimethylpolysiloxane / diphenylpolysiloxane copolymer having both ends silanol groups blocked by the formula (a), the following formula (f)

A composition 4 was obtained in the same manner except that 35 parts by mass of silanol group-blocked dimethylpolysiloxane having a viscosity of 280 Pa · s at 25 ° C.

で表される２５℃における粘度が４５０Ｐａ・ｓの両末端シラノール基封鎖ジメチルポリシロキサン３５質量部を用いる以外は同様にして、組成物５を得た。 [Comparative Example 2]
In Example 1, instead of the dimethylpolysiloxane / diphenylpolysiloxane copolymer having both ends silanol groups blocked represented by the formula (a), the following formula (g)

The composition 5 was obtained in the same manner except that 35 parts by mass of both ends silanol-blocked dimethylpolysiloxane having a viscosity at 25 ° C.

  The prepared compositions 1 to 5 were allowed to stand for 7 days and cured in an environment of 23 ° C. and 50% RH so that the sample thickness was 2 mm. Using the obtained cured product sample, the hardness of the sample was measured according to JIS K 6249. Moreover, the obtained hardened | cured material sample was cut | disconnected by 50 mm x 10 mm x 2 mm, and the Young's modulus in -50 degreeC and 25 degreeC was measured with the excitation frequency 1Hz in DMS-7100 by Hitachi High-Tech Science.

[Evaluation]
Examples 1 to 3 satisfy the requirements of the present invention, and a cured product of a condensation curable room temperature curable silicone rubber composition satisfying good low temperature characteristics is obtained.
On the other hand, for Comparative Example 1 and Comparative Example 2, organopolysiloxane as the main component does not satisfy the requirements of the present invention. As a result, although the hardness at room temperature and Young's modulus are equivalent, The increase in Young's modulus is remarkable and good rubber properties are not obtained.
From the above, it is clear that the composition obtained only becomes a condensation-curing room temperature curable silicone rubber composition having excellent low-temperature characteristics only after satisfying the requirements of the present invention.

Claims (4)

(A) The following average composition formula (1)
R _a R ¹ _b (R ² O) _c SiO _{(4-abc) / 2} (1)
Wherein R is independently an unsubstituted or substituted monovalent hydrocarbon group not containing an aromatic group, R ¹ is independently an unsubstituted or substituted aromatic monovalent hydrocarbon group, and R ² is Independently an unsubstituted or substituted monovalent hydrocarbon group or hydrogen atom that does not contain an aromatic group, a is a number from 1.7 to 2.2, b is a number from 0.02 to 0.1, c is a number from 0.0001 to 0.2, and a + b + c is a number satisfying 1.9 to 2.4, provided that the silicon atom at the end of the molecular chain is linked to the silicon atom adjacent to the silicon atom. The oxygen atom (O) may be substituted with the following divalent linking group —R′—.)
The molecule has a hydrolyzable group and / or hydroxyl group bonded to at least one silicon atom in the molecule, and the terminal is -R'-SiR " ₃ (wherein R 'is an oxygen atom or a carbon number of 1 And R ″ is independently R, R ¹ or OR ² , and at least one of the three R ″ is OR ^2. R, R ¹ and R ² are as described above. And 100 parts by mass of the organopolysiloxane blocked with
(B) The following general formula (2)

Wherein R ³ is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R ⁴ is independently an unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and d is 3 or 4)
An amino group-free hydrolyzable organosilane and / or a partial hydrolysis condensate thereof represented by: 0.2 to 30 parts by mass ,
(C) Amino group-containing hydrolyzable organosilane represented by the following general formula (3) and / or a partial hydrolyzate thereof : 0.1 to 10 parts by mass ,

(In the formula, R ⁷ is a C 7-10 divalent hydrocarbon group containing an aromatic ring, R ⁸ is a C 1-10 divalent hydrocarbon group, and R ⁹ and R ¹⁰ are each independent. Is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and g is 2 or 3. However, at least one of the primary and secondary amines is not directly connected to the aromatic ring of R ^7. .)
(D) Curing catalyst : 0.1 to 20 parts by mass ,
(E) at least one inorganic filler selected from calcium carbonate acid: 5 to 200 parts by weight,
(F) Molecular chain both ends trimethylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / diphenylsiloxane copolymer, and molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer A non-reactive dimethyl silicone oil or methylphenyl silicone oil selected from: 2 to 70 parts by mass , and a Young's modulus measured at 25 ° C. and an excitation frequency of 1 Hz is 1.0 × 10 ⁴ Pa or more. A condensation curable room temperature curable silicone rubber composition which gives a cured silicone rubber having a Young's modulus of 1.0 × 10 ⁸ Pa or less measured at −50 ° C. and an excitation frequency of 1 Hz.   The condensation curable room temperature curable silicone rubber composition according to claim 1, wherein the amount of component (E) is 5 to 142.9 parts by mass per 100 parts by mass of component (A).   The condensation curable room temperature curable silicone rubber composition according to claim 1 or 2, wherein the amount of component (F) is 2 to 57.1 parts by mass with respect to 100 parts by mass of component (A).   An electronic circuit sealed or adhesively fixed with a cured product of the condensation curable room temperature curable silicone rubber composition according to any one of claims 1 to 3.