JP2013100464A - Conductive silicone composition and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly conductive silicone composition which can be applied for coating, and which is excellent in shape retention after being applied and in storage stability, and to provide a method for producing the same.SOLUTION: An addition-curable conductive silicone composition includes: (A) an organopolysiloxane represented by average composition formula (1): RR'SiO, and containing at least two alkenyl groups bonded to a silicon atom in one molecule thereof; (B) an organohydrogenpolysiloxane containing at least two hydrogen atoms bonded to a silicon atom in one molecule thereof; (C) silver powder or silver-plated fine powder particles; (D) conductive fine powder (excluding silver, copper and metals containing them); (E) an addition reaction catalyst; and (F) one or more selected from among fatty acids, fatty acid derivatives and metal salts thereof. The conductive silicone composition can form a cured product, in particular a silicone rubber, giving a high conductivity of 1.0×10Ωcm or less, can be applied for coating, and is excellent in shape retention and storage stability.

Description

  The present invention relates to a conductive silicone composition that gives a conductive silicone cured product such as conductive silicone rubber, and in particular, is highly conductive and can be applied and has shape retention after application (before curing). The present invention relates to an addition-curable conductive silicone composition excellent in the manufacturing method, and a production method thereof.

  The conductive silicone rubber composition, after being cured, becomes a silicone rubber excellent in conductivity, and is used particularly in fields where heat resistance capable of exhibiting the characteristics of silicone is required. As the conductive silicone rubber composition, an organopolysiloxane having at least two alkenyl groups in one molecule, an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and a platinum catalyst An addition-curable conductive silicone rubber composition comprising silver powder and silver powder is known. As fillers for imparting high conductivity, reduced silver powder, electrolytic silver powder, atomized silver powder, silica or copper powder coated with silver plating has been used. There are various shapes such as a spherical shape, a flat shape, a dendritic shape, and an indefinite shape, but there are many flat silver powders that can be highly filled with silver powder and can have a high conductivity composition. It is used.

  However, if a metal powder such as silver powder or copper powder or a filler plated with silver is added to the addition-curing silicone rubber composition, it will act on the platinum group catalyst and the curability will deteriorate, or it will not cure over time was there.

Moreover, although the highly conductive silicone rubber composition is mainly used for electrical connection between conductors, it is necessary to use a low-viscosity silicone rubber composition that can be applied in order to make silver powder highly filled. There was a problem that the shape collapsed when applied or screen printed.
Examples of prior literature relating to these include the following.

JP-A 61-266462 Japanese Patent Laid-Open No. 3-170581 Japanese Patent Laid-Open No. 5-230373 JP-A-7-133432 Japanese Patent Laid-Open No. 7-150048 JP 2000-336273 A JP 2002-212426 A Japanese Patent Laid-Open No. 2004-27087 JP 2004-176165 A JP 2005-162827 A JP 2006-328302 A JP 2008-303233 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a highly conductive silicone composition that can be applied and is excellent in shape retention and storage stability after application, and a method for producing the same.

  As a result of intensive studies to achieve the above object, the present inventors have suppressed the deactivation of the platinum catalyst due to the highly filled silver powder in order to achieve both high conductivity and shape retention, and storage stability. In order to obtain an excellent composition, it has been found that it is effective to further add conductive fine powder, and one or more selected from fatty acids, fatty acid derivatives and metal salts thereof. It came to an eggplant.

That is, the present invention
(A) The following average composition formula (1)
R _a R ' _b SiO _{(4-ab) / 2} (1)
(In the formula, R is an alkenyl group, R ′ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms that does not have an aliphatic unsaturated bond, and a and b are 0 <a ≦ 2, 0 < (b <3, 0 <a + b ≦ 3)
An organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule represented by: 100 parts by mass
(B) Organohydrogenpolysiloxane containing hydrogen atoms bonded to at least two silicon atoms in one molecule: (A) all silicon atom-bonded alkenyl groups in component (B) silicon atoms in component (B) The amount of hydrogen atoms bonded to is 0.5 to 5.0 times mol,
(C) Silver powder or silver-plated fine powder particles: 100 to 1,500 parts by mass,
(D) Conductive fine powder (excluding silver and copper and metals containing them): 0.5 to 30 parts by mass,
(E) Addition reaction catalyst: catalytic amount, and (F) one or more selected from fatty acids, fatty acid derivatives and their metal salts: addition curable conductive silicone composition containing 0.1-20 parts by mass Offer things.

In this case, carbon black is preferable as the component (D). In addition, as part of the component (B), it is preferable to contain an organohydrogenpolysiloxane having a hydrogen atom bonded to at least two silicon atoms in one molecule and having an alkoxy group and an epoxy-containing group. The component F) is preferably stearic acid. The addition-curable conductive silicone composition of the present invention preferably has a thixotropy ratio (viscosity of 10 rpm / viscosity of 20 rpm) at 23 ° C. by an E-type viscometer of 1.5 or more, and a cured product of the composition of the present invention. The electrical conductivity is preferably 1.0 × 10 ⁻² Ω · cm or less.
Furthermore, in the present invention, when the addition-curable conductive silicone composition containing the above components (A) to (F) is produced, the components (E) and (F) previously mixed are mixed with other components. A method for producing an addition-curable conductive silicone composition is provided.

The conductive silicone composition of the present invention can form a cured product that gives a high conductivity of 1.0 × 10 ⁻² Ω · cm or less, in particular, a silicone rubber, and can be applied and retains its shape. And the storage stability is also good.

The conductive silicone composition of the present invention is
(A) The following average composition formula (1)
R _a R ' _b SiO _{(4-ab) / 2} (1)
(In the formula, R is an alkenyl group, R ′ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms that does not have an aliphatic unsaturated bond, and a and b are 0 <a ≦ 2, 0 < (b <3, 0 <a + b ≦ 3)
An organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule represented by: 100 parts by mass
(B) Organohydrogenpolysiloxane containing hydrogen atoms bonded to at least two silicon atoms in one molecule: (A) all silicon atom-bonded alkenyl groups in component (B) silicon atoms in component (B) The amount of hydrogen atoms bonded to is 0.5 to 5.0 times mol,
(C) Silver powder or silver-plated fine powder particles: 100 to 1,500 parts by mass,
(D) Conductive fine powder (excluding silver and copper and metals containing them): 0.5 to 30 parts by mass,
(E) Addition reaction catalyst: catalyst amount, and (F) 1 type (s) or 2 or more types chosen from a fatty acid, a fatty acid derivative, and those metal salts: 0.1-20 mass parts is contained.

(A) Alkenyl group-containing organopolysiloxane The alkenyl group-containing organopolysiloxane of component (A) is represented by the following average composition formula (1) and contains an alkenyl group bonded to at least two silicon atoms in one molecule. To do.
R _a R ' _b SiO _{(4-ab) / 2} (1)
(In the formula, R is an alkenyl group, R ′ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms that does not have an aliphatic unsaturated bond, and a and b are 0 <a ≦ 2, 0 < (b <3, 0 <a + b ≦ 3)

  The component (A) alkenyl group-containing organopolysiloxane is the main component (base polymer) of this composition, and an average of 2 or more (usually 2 to 50), preferably 2 to 20, more preferably in one molecule. Contains about 2-10 alkenyl groups bonded to silicon atoms. Examples of the alkenyl group R of the organopolysiloxane (A) include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group is particularly preferable. Examples of the bonding position of the alkenyl group of component (A) include molecular chain terminals and / or molecular chain side chains.

  In the organopolysiloxane of component (A), examples of the organic group R ′ bonded to a silicon atom other than an alkenyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group. Alkyl group; aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl group such as benzyl group, phenethyl group; chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, etc. In particular, a methyl group and a phenyl group are preferable.

  Examples of the molecular structure of the component (A) include linear, partially branched linear, cyclic, branched, and three-dimensional network. Basically, the main chain is diorgano A linear diorganopolysiloxane composed of repeating siloxane units (D units), both ends of which are blocked with triorganosiloxy groups, a linear diorganopolysiloxane and a branched or three-dimensional network A mixture of organopolysiloxanes is preferred.

In this case, as the resin-like (branched chain, three-dimensional network) organopolysiloxane, an alkenyl group and a SiO _4/2 unit (Q unit) and / or R ″ SiO _3/2 (T unit) (R ″ is The organopolysiloxane containing R or R ′) is not particularly limited, but may include SiO _4/2 units (Q units) and M such as RR ′ ₂ SiO _1/2 units and R ′ ₃ SiO _1/2 units. Examples thereof include a resinous organopolysiloxane composed of units and having an M / Q molar ratio of 0.6 to 1.2, and a resinous organopolysiloxane composed of T units and M units and / or D units.
The blending amount of the resinous organopolysiloxane is preferably 70:30 in terms of a mass ratio of a linear organopolysiloxane and a resinous organopolysiloxane in terms of the coating property of the composition and the filling property of the silver powder. ˜100: 0, particularly preferably 80:20 to 100: 0.

  a is 0 <a ≦ 2, preferably 0.001 ≦ a ≦ 1, b is 0 <b <3, preferably 0.5 ≦ b ≦ 2.5, and a + b is 0 <a + b ≦ 3, preferably Is a number satisfying 0.5 ≦ a + b ≦ 2.7. In the case of a linear organopolysiloxane, it is preferable that 0.001 ≦ a ≦ 1, 0.5 ≦ b ≦ 2.1, and 1.8 ≦ a + b ≦ 2.2.

  The viscosity at 23 ° C. of the component (A) is 100 to 5,000 mPa · s because the physical properties of the resulting silicone composition are good and the handling workability and applicability of the composition are good. It is preferable to be in the range of 100 to 1,000 mPa · s. When the resinous organopolysiloxane is used in combination with the linear organopolysiloxane, the resinous organopolysiloxane is dissolved in the linear organopolysiloxane, and therefore mixed to obtain a uniform viscosity. In the present invention, the viscosity can be measured with a rotational viscometer.

Examples of the organopolysiloxane of the component (A) include, for example, a trimethylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane copolymer, a molecular chain both-ends trimethylsiloxy group-capped methylvinylpolysiloxane, and both molecular chains. Terminal trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, molecular chain both ends dimethylvinylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends dimethylvinylsiloxy group-blocked methylvinylpolysiloxane, molecular chain both ends Dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane copolymer, dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer Both molecular chain terminals by trimethylsiloxy blocked with dimethylvinylsiloxy groups, wherein: the siloxane units of the formula R ¹ ₃ SiO _0.5: siloxane units represented by the formula R ^{1 ₂} R ₂ SiO _0.5: represented by R ¹ ₂ SiO An organosiloxane copolymer comprising a siloxane unit represented by the formula: SiO ₂ and a siloxane unit represented by the formula: R ¹ ₃ SiO _0.5 and a siloxane unit represented by the formula: R ¹ ₂ R ² SiO _0.5 : An organosiloxane copolymer composed of siloxane units represented by SiO ₂ , a siloxane unit represented by formula: R ¹ ₂ R ² SiO _0.5 and a siloxane unit represented by formula: R ¹ ₂ SiO and a formula: SiO ₂ Organosiloxane copolymer comprising siloxane units, siloxane units represented by the formula: R ¹ R ² SiO and silos represented by the formula: R ¹ SiO _1.5 Examples thereof include an organosiloxane copolymer comprising a siloxane unit represented by a xan unit or a formula: R ² SiO _1.5 , and a mixture comprising two or more of these organopolysiloxanes.

Here, R ¹ in the above formula is a monovalent hydrocarbon group other than an alkenyl group, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group; Groups, tolyl groups, xylyl groups, naphthyl groups and other aryl groups; benzyl groups, phenethyl groups and other aralkyl groups; chloromethyl groups, 3-chloropropyl groups, 3,3,3-trifluoropropyl groups and other alkyl halides Group and the like. R ² in the above formula is an alkenyl group, and examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group.

(B) Organohydrogenpolysiloxane The organohydrogenpolysiloxane (B) used in the composition of the present invention is at least 2 (usually 2 to 300), preferably 3 or more (for example, 3) in one molecule. About 150 to about 150), more preferably about 3 to 100 hydrogen atoms bonded to silicon atoms (that is, SiH groups), and have a linear, branched, cyclic, or three-dimensional network structure. Any of resinous materials may be used. Examples of such organohydrogenpolysiloxanes include organohydrogenpolysiloxanes represented by the following average composition formula (2).

H _c R ³ _d SiO _{(4-cd) / 2} (2)
(Wherein R ³ independently represents an unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, or an alkoxy group, and c and d are 0 <c <2, 0.8 ≦ d. ≦ 2 and 0.8 <c + d ≦ 3, preferably 0.05 ≦ c ≦ 1, 1.5 ≦ d ≦ 2, and 1.8 ≦ c + d ≦ 2.7. The number (or degree of polymerization) of silicon atoms in one molecule is preferably 2 to 100, particularly 3 to 50.)

Here, examples of the unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond represented by R ³ in the above formula include those similar to those exemplified as R ′ above, a methoxy group, Examples of the alkoxy group such as an ethoxy group and the substituted monovalent hydrocarbon group include an epoxy group-containing monovalent hydrocarbon group, and typical ones have 1 to 10 carbon atoms, particularly those having 1 to 7 carbon atoms. And preferably a lower alkyl group having 1 to 3 carbon atoms such as a methyl group, a 3,3,3-trifluoropropyl group, or an alkoxy group having 1 to 4 carbon atoms. In this case, examples of the epoxy group-containing monovalent hydrocarbon group include the above-described unsubstituted monovalent hydrocarbon groups, particularly those in which one or more hydrogen atoms of the alkyl group are substituted with glycidyl groups or glycidoxy groups. R ³ is particularly preferably a methyl group, a methoxy group, an ethoxy group, or an epoxy group-containing monovalent hydrocarbon group.

（式中、Ｒ³は前記と同じであり、ｓ、ｔはそれぞれ０又は１以上の整数である。）
等で表されるものが挙げられる。 Examples of such organohydrogenpolysiloxanes include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyltetracyclosiloxane, 1,3,5,7,8- Siloxane oligomers such as pentamethylpentacyclosiloxane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, tris (dimethylhydrogensiloxy) methylsilane; Siloxane, trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, molecular chain both ends silanol group-blocked methylhydrogenpolysiloxane, molecular chain both ends silanol-blocked dimethyl Loxane / methylhydrogensiloxane copolymer, dimethylhydrogensiloxy group-blocked dimethylpolysiloxane at both ends of the molecular chain, dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane at both ends of the molecular chain, dimethylhydrogensiloxy group-blocked at both ends of the molecular chain Dimethylsiloxane / methylhydrogensiloxane copolymer, etc .; composed of R ³ ₂ (H) SiO _1/2 unit and SiO _4/2 unit, optionally R ³ ₃ SiO _1/2 unit, R ³ ₂ SiO _2/2 In addition to units, R ³ (H) SiO _2/2 units, (H) SiO _3/2 units or silicone resins that can contain R ³ SiO _3/2 units (wherein R ³ is the same as above), etc. In these exemplified compounds, those in which part or all of the methyl group is substituted with other alkyl groups such as ethyl group, propyl group, etc. The following formula

(In the formula, R ³ is the same as described above, and s and t are each 0 or an integer of 1 or more.)
And the like.

In addition, when adhesiveness is important, a part or all of the component (B) has an alkoxy group such as a methoxy group or an ethoxy group and / or an epoxy in the molecule represented by the following formulas (3) and (4). It is preferable to use one having a containing group. In particular, an organohydrogenpolysiloxane having an alkoxy group and an epoxy-containing group such as a glycidyl group, a glycidoxy group, or a glycidoxypropyl group in the molecule represented by the formula (4) is effective for improving the adhesion. is there.

The organohydrogenpolysiloxane used in the composition of the present invention can be obtained by a known method, for example, the general formula: R ³ SiHCl ₂ and R ³ ₂ SiHCl (wherein R ³ is the same as above) Or (co) hydrolyzing at least one chlorosilane selected from: or at least selected from the general formula: R ³ ₃ SiCl and R ³ ₂ SiCl ₂ (wherein R ³ is as defined above) It can be obtained by cohydrolyzing and condensing one kind of chlorosilane. Further, the organohydrogenpolysiloxane may be one obtained by equilibrating the polysiloxane obtained by (co) hydrolysis condensation.

  The blending amount of the component (B) is 0.5 to 5.0 times mol of hydrogen atoms bonded to silicon atoms in the component (B) with respect to alkenyl groups bonded to all silicon atoms in the component (A). It is preferable that it is the quantity which becomes 0.7-3.0 times mole. If it is less than 0.5 or 5.0 or more, the crosslinking balance may be lost and a cured product having sufficient strength may not be obtained.

(C) Silver powder or silver-plated fine powder particles In order to impart conductivity to the cured product of the silicone composition, silver powder or silver-plated fine powder particles are used as the conductive filler in the present invention. The Specific examples of the silver powder include reduced silver powder, electrolytic silver powder, and atomized silver powder. The shape of component (C) includes various shapes such as a spherical shape, a flat shape, a dendritic shape, and an indefinite shape, but is not particularly limited. However, in order to obtain a highly conductive composition, flat silver powder is preferable for high filling with silver powder. In addition, as for the fine powder particles plated with silver, a substrate to be plated such as silica or copper is commercially available, but is not particularly limited. In order to coat the surface with silver, a spherical substrate is preferable. The average particle size of the component (C) is not particularly limited, but is preferably 0.1 to 15 μm. This average particle diameter can be obtained as a cumulative mass average value D ₅₀ in a particle size distribution measuring apparatus by a laser beam diffraction method.

  Silver powder contains a rust inhibitor, a lubricant for preventing aggregation, and the like depending on the manufacturing process. When they act on a platinum group catalyst that is an addition reaction catalyst, there may be a case where a curing delay is caused or no curing occurs at all. Therefore, it is preferable to use a silver powder or silver plating filler that has been previously washed with a large amount of water or an organic solvent such as acetone or methyl ethyl ketone and then dried.

  (C) The compounding quantity of a component needs to be 100-1,500 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 300-1,000 mass parts. When the component (C) is less than 100 parts by mass, the conductivity of the cured product is lowered, and when it is more than 1,500 parts by mass, it is difficult to handle the composition.

(D) Conductive fine powder (excluding silver, copper and metals containing them)
The component (D) is used to improve thixotropy while maintaining the conductivity of the composition and to enhance shape retention. Examples of the powder that imparts conductivity include carbon black and conductive zinc white. In the present invention, which is a composition having high conductivity, it is more preferable to use carbon black.

  As carbon black, those commonly used in conductive rubber compositions can be used, for example, acetylene black, conductive furnace black (CF), super conductive furnace black (SCF), extra conductive furnace black (XCF), and conductive. Examples thereof include channel black (CC), furnace black and channel black heat-treated at a high temperature of about 1,500 to 3,000 ° C. Among these, acetylene black has a low impurity content and has a developed secondary structure structure, so that it has excellent conductivity and is particularly preferably used in the present invention.

  (D) The addition amount of a component is 0.5-30 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 1-25 mass parts, Most preferably, it is 3-20 mass parts. When the addition amount is less than 0.5 parts by mass, the thixotropy improving effect is not sufficient, and the shape retention after application of the composition is deteriorated. When the addition amount is more than 30 parts by mass, the viscosity increases too much and the composition Workability is reduced.

(E) Addition reaction catalyst The addition reaction catalyst (hydrosilylation reaction catalyst) used in the present invention comprises an alkenyl group of the component (A) and a hydrogen atom (that is, SiH group) bonded to a silicon atom of the component (B). As a catalyst for promoting the addition reaction of platinum, a known catalyst such as a platinum group metal catalyst can be used as the catalyst used in the hydrosilylation reaction.

As the platinum group metal catalyst, all known catalysts such as platinum group metal catalysts such as platinum, rhodium and palladium can be used as hydrosilylation reaction catalysts. For example, platinum group metals such as platinum black, rhodium and palladium; H ₂ PtCl ₄ · yH ₂ O, H ₂ PtCl ₆ · yH ₂ O, NaHPtCl ₆ · yH ₂ O, KHPtCl ₆ · yH ₂ O, Na ₂ PtCl ₆ · yH ₂ O, K ₂ PtCl ₄ · yH ₂ O, PtCl ₄ · yH ₂ O, PtCl ₂ , Na ₂ HPtCl ₄ · yH ₂ O (wherein y is an integer of 0 to 6, preferably 0) Or chloroplatinic acid and chloroplatinate; alcohol-modified chloroplatinic acid (see US Pat. No. 3,220,972); complex of chloroplatinic acid and olefin (US patent) 3,159,601 specification, 3,159,662 specification, 3,775,452 specification); platinum group metals such as platinum black, palladium, etc., alumina, silica, carbon, etc. Supported on the carrier Rhodium-olefin complex; Chlorotris (triphenylphosphine) rhodium (Wilkinson catalyst); Platinum chloride, chloroplatinic acid or chloroplatinate and vinyl group-containing siloxane, especially vinyl group-containing cyclic siloxane Can be mentioned. Among these, from the viewpoint of compatibility and chlorine impurities, chloroplatinic acid modified with silicone may be mentioned. Specifically, for example, chloroplatinic acid modified with tetramethyldivinyldisiloxane may be used. A catalyst is mentioned.

  The amount of component (E) added is 0.5 to 1,000 ppm, preferably 1 to 500 ppm, more preferably 5 to 200 ppm in terms of mass with respect to component (A) in terms of platinum atoms.

(F) Fatty acids selected from fatty acids, fatty acid derivatives and their metal salts (F) Fatty acids, fatty acid derivatives, or their metal salts are components that are added to stabilize the addition curability of the composition. Commercially available products can also be used.
(F) The addition amount of a component is 0.1-20 mass parts with respect to 100 mass parts of (A) component, Preferably it is 0.1-5 mass parts. If it is less than 0.1 parts by mass, the effect of improving the storage stability may be insufficient, and if it exceeds 20 parts by mass, the curability is deteriorated. Here, the 1 type or 2 or more types of preferable carbon number chosen from a fatty acid, a fatty acid derivative, and those metal salts is 8 or more, More preferably, it is 8-20.

  Specific examples of fatty acids include caprylic acid, undecylenic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, alginate, lignoceric acid, serotic acid, melissic acid, myristoleic acid, oleic acid, linol Examples include acids and linolenic acid.

Examples of the fatty acid derivatives include fatty acid esters and aliphatic alcohol esters. The aliphatic esters, lower alcohol esters of the above fatty acids and C ₁ -C _5, sorbitan esters, polyhydric alcohol esters such as glycerol esters are exemplified. Examples of fatty alcohol esters include dibasic acid esters such as capricyl alcohol, capryl alcohol, lauryl alcohol, myristyl alcohol, saturated alcohols such as stearyl alcohol, fatty acid alcohols such as glutaric acid esters and speric acid esters, and citrate esters. Examples of such tribasic acid esters are as follows.

  Examples of fatty acids in the fatty acid metal salt include caprylic acid, undecylenic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, alginate, lignoceric acid, serotic acid, melissic acid, myristic acid, oleic acid, Examples of the metal include linoleic acid and linolenic acid, and examples of the metal include lithium, calcium, magnesium, and zinc.

  (F) As a component, a fatty acid is preferable and a stearic acid is more preferable. Although the component (F) may be used alone, it is preferable to use a component previously mixed with the component (E) because the storage stability can be further improved.

  The composition of the present invention may be a one-component composition or a two-component composition mixed just before use, as with a normal addition-curable silicone composition, but is preferably a one-component composition from the viewpoint of workability. .

Various additives can be further added to the composition of the present invention as long as the object of the present invention is not impaired. In particular, a hydrosilylation reaction inhibitor can be blended to improve storage stability when the composition of the present invention is used in a one-pack type. As the reaction inhibitor, conventionally known ones can be used. For example, acetylene compounds, compounds containing two or more alkenyl groups, compounds containing alkynyl groups, triallyl isocyanurate and modified products thereof, etc. Is mentioned. Among these, it is desirable to use a compound having an alkenyl group or an alkynyl group.
If the addition amount of these reaction inhibitors is too small, the effect of retarding the hydrosilylation reaction may not be obtained. Conversely, if too large, curing itself may be inhibited, so that (A) to (F) ) It is preferable that it is the range of 0.01-1.0 mass part with respect to 100 mass parts of total amounts of a component.
Moreover, a silane coupling agent can also be mix | blended in order to improve adhesiveness.

  Examples of the method for producing the addition-curable conductive silicone composition of the present invention include a method of mixing the components (A) to (F) and other optional components with a mixer such as a planetary mixer, a kneader, or a Shinagawa mixer. Can be mentioned. In this case, it is preferable to mix the component (E) and the component (F) previously mixed with other components from the viewpoint of further improving the storage stability of the composition.

  In the present invention, the viscosity and thixotropic coefficient of the composition are important factors in shape stability after coating. The viscosity of the composition at 23 ° C. when the rotational speed when using an E-type viscometer is 10 rpm is preferably 10 Pa · s or more and 500 Pa · s or less, particularly preferably 20 to 200 Pa · s. If the viscosity is too low, the shape may not be maintained when applied with a dispenser or the like or when heated and cured. On the other hand, if the viscosity is too high, stringing may occur when applying with a dispenser, or the pattern of the mask may not be sufficiently followed when screen printing is performed. The ratio of the composition at 23 ° C. at 10 rpm to the viscosity at 20 rpm (10 rpm / 20 rpm) (hereinafter referred to as the thixo coefficient) is 1.5 or more, particularly 2.0 to 5.0. preferable. If the thixo factor is less than 1.5, it may be insufficient to stabilize the applied shape. If shape stability after application is important, the thixo factor is 1.5 or more. Is preferably used.

As curing conditions for the composition of the present invention, it is desirable to cure at 100 to 150 ° C. for 1 to 120 minutes. In this case, the conductivity of the cured product is preferably adjusted to 1.0 × 10 ⁻² Ω · cm or less by adjusting the blending amount of the components (C) and (D), particularly 1.0 × 10 ^−2. It is preferable that it is -1.0 * 10 < ^-5 > ohm * cm.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to a following example.

（Ｃ）福田金属箔粉工業（株）製銀粉（ＡｇＣ−２３７）をアセトンで洗浄、乾燥させたもの
（Ｄ）電気化学工業（株）製デンカブラックＨＳ−１００
（Ｅ−１）塩化白金酸から誘導した、テトラメチルジビニルジシロキサンを配位子として有する白金触媒（白金原子量：１質量％）
（Ｅ−２）上記（Ｅ−１）とステアリン酸を質量比３／２で混合したもの
（Ｆ）ステアリン酸
（Ｇ）ＢＥＴ法による比表面積が２００ｍ²／ｇであり、表面がヘキサメチルジシラザンで処理された煙霧質シリカ
（反応抑制剤）１−エチニル−１−シクロヘキサノール [Examples 1-4, Comparative Examples 1-4]
The components shown below were blended uniformly in the blending amounts shown in Tables 1 and 2 using a rotation / revolution mixer manufactured by Shinkey Co., Ltd. (Aritori Kentaro) to prepare a silicone rubber composition. In Examples and Comparative Examples, the viscosity is a value measured at 23 ° C. with an E-type viscometer (RE80 manufactured by Toki Sangyo Co., Ltd.).
(A) Methyl vinyl polysiloxane (B-1) having two vinyl groups directly bonded to silicon atoms in one molecule and having a viscosity of 600 mPa · s, a viscosity at 23 ° C. of 5 mPa · s, and a hydrogen gas generation amount SiH group-containing compound represented by formula (4) of methyl hydrogen polysiloxane (B-2) which is 350 ml / g

(C) Fukuda Metal Foil Powder Co., Ltd. silver powder (AgC-237) washed with acetone and dried (D) Denka Black HS-100 manufactured by Denki Kagaku Kogyo Co., Ltd.
(E-1) A platinum catalyst derived from chloroplatinic acid and having tetramethyldivinyldisiloxane as a ligand (platinum atomic weight: 1% by mass)
(E-2) A mixture of the above (E-1) and stearic acid at a mass ratio of 3/2. (F) Stearic acid (G) The specific surface area by the BET method is 200 m ² / g, and the surface is hexamethyldi Silica-treated fumed silica (reaction inhibitor) 1-ethynyl-1-cyclohexanol

The results of conductivity, viscosity, thixotropic coefficient, shape retention and storage stability of the obtained silicone rubber composition are shown in Tables 1 and 2. In addition, electrical conductivity, shape retention, and storage stability were performed by the methods shown below.
[Measurement of conductivity]
The silicone rubber composition was oven-cured in a 1 mm thick mold at 150 ° C./1 hour to form a conductive silicone rubber sheet.
The measurement of conductivity is
KEITHLEY 237 High Voltage Source Measurement Unit (constant current power supply)
KEITLEY 2000 Multimeter (Voltmeter)
It was performed using.
[Shape retention]
Regarding shape retainability, the composition is placed on a stainless steel (SUS) plate of 25 mm × 250 mm (thickness 0.5 mm), and the flowability of the composition when tilted 30 degrees and cured at 150 ° C./1 hour, (No change at all), ○ (not flowing but slightly tilted), Δ (flowing 1 to 3 mm), × (flowing beyond 3 mm).
[Storage stability]
Hardness was measured with a durometer type A hardness meter immediately after production and when the composition stored at 5 ° C. for 2 months was cured at 150 ° C./1 hour.

Claims (7)

(A) The following average composition formula (1)
R _a R ' _b SiO _{(4-ab) / 2} (1)
(In the formula, R is an alkenyl group, R ′ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms that does not have an aliphatic unsaturated bond, and a and b are 0 <a ≦ 2, 0 < (b <3, 0 <a + b ≦ 3)
An organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule represented by: 100 parts by mass
(B) Organohydrogenpolysiloxane containing hydrogen atoms bonded to at least two silicon atoms in one molecule: (A) all silicon atom-bonded alkenyl groups in component (B) silicon atoms in component (B) The amount of hydrogen atoms bonded to is 0.5 to 5.0 times mol,
(C) Silver powder or silver-plated fine powder particles: 100 to 1,500 parts by mass,
(D) Conductive fine powder (excluding silver and copper and metals containing them): 0.5 to 30 parts by mass,
(E) addition reaction catalyst: catalyst amount,
(F) 1 type, or 2 or more types chosen from a fatty acid, a fatty-acid derivative, and those metal salts: 0.1-20 mass parts of addition curable conductive silicone compositions characterized by the above-mentioned.   The addition-curable conductive silicone composition according to claim 1, wherein the component (D) is carbon black.   The component (B) contains an organohydrogenpolysiloxane having a hydrogen atom bonded to at least two silicon atoms in one molecule, and having an alkoxy group and an epoxy-containing group. Addition-curable conductive silicone composition.   (F) Component is a stearic acid, The addition-curable conductive silicone composition of any one of Claims 1-3.   The addition curing type conductive silicone composition according to any one of claims 1 to 4, wherein a thixotropy ratio (viscosity of 10 rpm / viscosity of 20 rpm) at 23 ° C by an E-type viscometer is 1.5 or more. The addition-curable conductive silicone composition according to any one of claims 1 to 5, wherein the conductivity of the cured product is 1.0 x ^10-2 Ω · cm or less.   In producing the addition-curable conductive silicone composition containing the components (A) to (F) according to any one of claims 1 to 6, the components (E) and (F) were mixed in advance. A method for producing an addition-curable conductive silicone composition, comprising mixing a product with other components.