JP2022143344A - Conductive silicone composition, conductive silicone cured product, and laminate - Google Patents

Abstract

To provide an addition-curable conductive silicone composition which has high conductivity and good adhesiveness to metals such as aluminum and copper.SOLUTION: The conductive silicone composition contains: (A) an organopolysiloxane which has at least two groups having a hydrosilylation-reactive carbon-carbon unsaturated bond in one molecule; (B) an organohydrogenpolysiloxane which has at least two SiH groups in one molecule; (C) a bis(β-diketonato)platinum complex; (D) conductive particles; (E) an organic peroxide; (F) a compound having an oxacyclopropane structure; and (G) a carboxylic acid anhydride.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a conductive silicone composition, a cured product thereof, and a laminate comprising the cured product.

A conductive adhesive made by dispersing conductive particles in a solvent or resin as an alternative to solder, which has traditionally required high-temperature mounting, for applications such as bonding semiconductors and crystal oscillators to substrates and forming circuits. A conductive composition called a conductive paste or the like is widely used (Patent Document 1).

Epoxy resins, which have been widely used as binders for these conductive compositions, are excellent in mechanical strength such as adhesive strength, but are inferior in flexibility and stretchability, and the base material itself that forms a circuit such as a so-called wearable device. It was difficult to apply to applications that bend and stretch.

To address such problems, the use of silicone resins and the like as binders with superior flexibility has been investigated (Patent Document 2). As a method for curing silicone resins, addition curing utilizing a hydrosilylation reaction between unsaturated carbon groups and SiH groups is mainly used.

Japanese Patent Application Laid-Open No. 2000-319622 JP 2004-119254 A

Addition-curable silicone compositions containing a high proportion of conductive particles tend to exhibit poor curability under oxygen-deficient conditions. When heated at a relatively low temperature, the inside of the bonded portion does not harden, and there is a problem that the adhesiveness to metal such as copper used as an adherend of the conductive adhesive is insufficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an addition-curable conductive silicone composition having high conductivity and good adhesion to metals such as aluminum and copper.

In order to achieve the above object, in the present invention,
(A) an organopolysiloxane having at least two groups per molecule having a hydrosilylation-reactive carbon-carbon unsaturated bond;
(B) an organohydrogenpolysiloxane having at least two SiH groups per molecule;
(C) a bis(β-diketonato)platinum complex,
(D) conductive particles;
(E) an organic peroxide,
Provided is a conductive silicone composition comprising (F) a compound having an oxacyclopropane structure and (G) a carboxylic anhydride.

With such a composition, an addition-curable conductive silicone composition having good adhesion to metals can be obtained.

Further, the number of SiH groups in the component (B) is 0.5 to 10.0 per one hydrosilylation-reactive carbon-carbon unsaturated bond in the component (A). is preferred.

With such a composition, a cured product having excellent mechanical properties can be obtained.

Moreover, it is preferable that said (D) component is a silver powder.

With such a material, it is possible to impart higher conductivity to the cured product.

Also, the content of the component (D) is preferably 50 to 99% by mass relative to the total mass of the composition.

With such a composition, it is possible to obtain a composition having excellent curability and handleability, and to impart sufficient electrical conductivity to the cured product.

Moreover, the component (E) is preferably an organic peroxide having a peroxycarbonate structure, an alkylperester structure, or a dialkylperoxide structure.

With such a composition, the hydrosilylation catalyst can be activated at a lower temperature, and an addition-curable conductive silicone composition having even better curability and adhesiveness can be obtained.

Also, the component (G) is preferably an intramolecular carboxylic acid anhydride having a tetrahydro-2,5-dioxofuran structure.

With such a material, the adhesiveness to metal can be further enhanced.

（式中、Ｒ^４は置換もしくは非置換の１価炭化水素基又は水素原子であり、Ｒ^５は置換又は非置換の１価炭化水素基であり、Ｒ^６は互いに同一又は異なっていても良い置換もしくは非置換の１価炭化水素基又はアルコキシ基である。） Further, (H) preferably contains at least one organosilicon compound selected from compounds represented by the following general formulas (3) to (5) and stereoisomers thereof.

(wherein R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group or hydrogen atom, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon group, and R ⁶ may be the same or different A substituted or unsubstituted monovalent hydrocarbon group or alkoxy group.)

With such a material, foaming during curing can be suppressed.

The present invention also provides a cured conductive silicone composition, which is a cured conductive silicone composition having a volume resistivity of 1.0×10 ⁻³ Ω·cm or less.

With such a material, a highly conductive cured product can be obtained.

The present invention also provides a laminate comprising the cured conductive silicone material described above.

With such a material, a laminate having high conductivity can be obtained.

The conductive silicone composition of the present invention provides a cured silicone product that has high conductivity and excellent adhesion to metals such as aluminum and copper. The conductive silicone composition of the present invention having such properties is useful as a conductive adhesive or conductive paste for bonding electronic parts and elements to substrates, forming electronic circuits, and the like.

As described above, there has been a demand for the development of addition-curable conductive silicone compositions that are highly conductive and have excellent adhesion to metals.

As a result of intensive studies aimed at solving the above problems, the inventors of the present invention have found that, in a conductive adhesive obtained by filling an addition-curable liquid silicone rubber with a conductive filler, a hydrosilylation catalyst having a specific structure, an organic peroxide, and the like , found that a conductive adhesive having good adhesion to metals such as aluminum and copper can be obtained by blending a compound having an oxacyclopropane structure and a carboxylic anhydride, and completed the present invention.

That is, the present invention
(A) an organopolysiloxane having at least two groups per molecule having a hydrosilylation-reactive carbon-carbon unsaturated bond;
(B) an organohydrogenpolysiloxane having at least two SiH groups per molecule;
(C) a bis(β-diketonato)platinum complex,
(D) conductive particles;
(E) an organic peroxide,
A conductive silicone composition comprising (F) a compound having an oxacyclopropane structure and (G) a carboxylic anhydride.

Although the present invention will be described in detail below, the present invention is not limited thereto.

[Conductive silicone composition]
The conductive silicone composition of the present invention contains the following components (A) to (G).

[(A) component]
Component (A) in the conductive silicone composition of the present invention is an organopolysiloxane having at least two groups having hydrosilylation-reactive carbon-carbon unsaturated bonds in one molecule.

As component (A), for example, an organopolysiloxane represented by the following average formula (1) can be used.

In the average formula (1), R ¹ is a group having a hydrosilylation-reactive carbon-carbon unsaturated bond, R ² may be the same or different without a hydrosilylation-reactive carbon-carbon unsaturated bond, It is a substituted or unsubstituted monovalent hydrocarbon group. However, a, b, c, d, e, f, and g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, and g≧0, respectively. , where b+c+e>0 and a+b+c+d+e+f+g=1. Moreover, the arrangement order of each siloxane unit is arbitrary.

Examples of groups having a hydrosilylation-reactive carbon-carbon unsaturated bond for R ¹ include vinyl groups, allyl groups, octenyl groups, dodecenyl groups, norbornenyl groups, isonorbornenyl groups, acryloyl groups, methacryloyl groups, and the like. It is preferably an alkenyl group having 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and particularly preferably a vinyl group.

Component (A), the organopolysiloxane, contains at least 2, preferably 2 to 6 groups having hydrosilylation-reactive carbon-carbon unsaturated bonds per molecule. These groups may be located on either one of the molecular chain terminal and the molecular chain side chain (non-terminal of the molecular chain) of component (A), or may be located on both of them.

R ² is not particularly limited as long as it does not contain a hydrosilylation-reactive carbon-carbon unsaturated bond. Examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group and s-butyl group. , isobutyl group, t-butyl group, n-pentyl group, neopentyl group, isopentyl group, s-pentyl group, 2-pentyl group, hexyl group, heptyl group, octyl group, alkyl group such as 2-ethylhexyl group; cyclopentyl group , cycloalkyl groups such as cyclohexyl group; phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group and other aryl groups; benzyl group, phenethyl group and other aralkyl groups; chloromethyl group, 3-chloropropyl group, trifluoro A methyl group, a halogenated alkyl group such as a 3,3,3-trifluoropropyl group, etc., preferably having 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 8, unsubstituted or Halogen-substituted monovalent hydrocarbon groups can be mentioned, and a methyl group is particularly preferred.

Specific examples of the component (A) include dimethylsiloxane with both ends blocked with dimethylvinylsiloxy groups, methylvinylsiloxane with both ends with trimethylsiloxy groups blocked, dimethylvinylsiloxane with both ends blocked with cyclic methylvinylsiloxane copolymer, and cyclic methylvinylsiloxane. , both terminal dimethylvinylsiloxy group-blocked dimethylsiloxane/cyclic diphenylsiloxane copolymer, both terminal dimethylvinylsiloxy group-blocked dimethylsiloxane/cyclic methylphenylsiloxane copolymer, both terminal methylphenylvinsiloxy group-blocked dimethylsiloxane, both terminal methyl phenylvinylsiloxy group-blocked diphenylsiloxane, both ends methylphenylvinylsiloxy group-blocked methylphenylsiloxane, both ends methylphenylvinylsiloxy group-blocked dimethylsiloxane/cyclic diphenylsiloxane copolymer, (CH ₂ =CH) (CH ₃ ) ₂ SiO Examples thereof include copolymers composed of _1/2 units, (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units. Component (A) may be used alone or in combination of two or more.

Although the kinematic viscosity of component (A) is not particularly limited, it is preferably in the range of 10 to 100,000 mm ² /s, more preferably in the range of 100 to 10,000 mm ² /s. The kinematic viscosity can be measured at 25° C. using, for example, an Ubbelohde viscometer or a Canon-Fenske viscometer. Within such a range, the composition is excellent in handleability.

[(B) Component]
The component (B) in the conductive silicone composition of the present invention acts as a cross-linking agent that cross-links the hydrosilylation-reactive carbon-carbon unsaturated bonds contained in the component (A) by a hydrosilylation reaction. Component (B) is an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms (SiH groups) per molecule.

As component (B), for example, an organohydrogenpolysiloxane represented by the following average formula (2) can be used.

In the average formula (2), R ³ is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different and which does not contain a hydrosilylation-reactive carbon-carbon unsaturated bond. provided that h, i, j, k, l, m, and n are numbers satisfying h≧0, i≧0, j≧0, k≧0, l≧0, m≧0, and n≧0, respectively. , i+j+l>0 and h+i+j+k+l+m+n=1. Moreover, the arrangement order of each siloxane unit is arbitrary.

Specific examples of R ³ include the same groups as those for R ² above, preferably having 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 8 carbon atoms, unsubstituted or halogen-substituted A monovalent hydrocarbon group can be mentioned, and a methyl group is particularly preferred.

The component (B) organohydrogenpolysiloxane compound has at least 2, preferably 3 to 300, particularly preferably 3 to 100 silicon-bonded hydrogen atoms per molecule. When the organohydrogenpolysiloxane of component (B) has a linear structure, these SiH groups may be located only at either the terminal of the molecular chain or the side chain of the molecular chain (non-terminal of the molecular chain). , and both.

Specific examples of component (B) include, for example, dimethylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, methylhydrogensiloxane-dimethylsiloxane copolymer blocked at both ends with trimethylsiloxy groups, and dimethylhydrogensiloxy group-blocked at both ends. Dimethylsiloxane/cyclic methylhydrogensiloxane copolymer, cyclic methylhydrogensiloxane, both ends dimethylphenylsiloxy group-blocked methylphenylhydrogensiloxane/dimethylsiloxane cyclic copolymer, both ends dimethylphenylsiloxy group-blocked diphenylsiloxane/methylhydro gensiloxane copolymer, diphenylpolysiloxane capped with methylphenylhydrogensiloxy groups at both ends, dimethylsiloxane-diphenylsiloxane-methylhydrogensiloxane copolymer capped with methylphenylhydrogensiloxy groups at both ends, diphenylhydrogensiloxy group-capped at both ends Examples thereof include dimethylsiloxane/diphenylsiloxane/methylhydrogensiloxane copolymer, diphenylpolysiloxane having one terminal methylphenylhydrogen group and one terminal dimethylhydrogen group-blocked.

The (B) component organohydrogenpolysiloxane compound may be used alone or in combination of two or more.

Although the kinematic viscosity of component (B) is not particularly limited, it is preferably in the range of 10 to 1,000 mm ² /s, more preferably in the range of 10 to 100 mm ² /s. The kinematic viscosity can be measured at 25° C. using, for example, an Ubbelohde viscometer or a Canon-Fenske viscometer. Within such a range, the composition is excellent in handleability.

The amount of component (B) to be blended is preferably such that the number of silicon-bonded hydrogen atoms (SiH groups) in component (B) per one hydrosilylation-reactive carbon-carbon unsaturated bond in component (A) is is an amount within the range of 0.5 to 10.0, more preferably 1.0 to 6.0. Within such a range, a cured product having excellent mechanical properties can be obtained.

[(C) component]
The (C) component in the conductive silicone composition of the present invention is a bis(β-diketonato)platinum complex, and the hydrosilylation-reactive carbon-carbon unsaturated bond in the (A) component and the Acts as a hydrosilylation catalyst to promote hydrosilylation reactions with silicon-bonded hydrogen atoms. Furthermore, by using such a component (C) as a hydrosilylation catalyst, the conductive silicone composition of the present invention becomes a composition having excellent storage stability without blending a reaction control agent.

Bis(β-diketonato)platinum complexes include, for example, bis(1,3-propanedionato)platinum complex, bis(2,4-pentanedionato)platinum complex, bis(2,4-hexanedionato)platinum complex , bis(2,4-heptanedionato)platinum complex, bis(3,5-heptanedionato)platinum complex, bis(1-phenyl-1,3-butanedionato)platinum complex, bis(1,3-diphenyl-1,3 -propanedionato)platinum complex and the like, preferably bis(1,3-propanedionato)platinum complex.

The content of component (C) is preferably 0.001 to 0.5 parts by mass, more preferably 0.01 to 0.1 parts by mass, in terms of platinum atomic mass with respect to 100 parts by mass of component (A). preferable. Within such a range, a composition having excellent curability and storage stability can be obtained.

[(D) Component]
The component (D) in the conductive silicone composition of the present invention is conductive particles.

Component (D) may be any material as long as it has electrical conductivity. Metal-plated particles, zinc oxide, titanium oxide, antimony-doped tin oxide (ATO), phosphorous-doped tin oxide (PTO), indium tin oxide (ITO), fluorine-doped tin oxide (FTO), etc. can be used, and are electrically conductive. from the viewpoint of silver powder and silver-plated powder.

Examples of silver powder that can be used include those manufactured by Mitsubishi Materials Corporation, those manufactured by Fukuda Metal Foil and Powder, those manufactured by Tokuriki Honten, those manufactured by Dowa Electronics, and those manufactured by Tanaka Kikinzoku.

The conductive particles may have any shape such as spherical, flaky, dendritic, amorphous, or a mixture thereof, but flakes are particularly preferred. Here, the flake shape includes what is called a flat shape, a flaky shape, a scaly shape, and the like.

The average particle size of the conductive particles is preferably in the range of 0.1-100 μm, more preferably in the range of 0.1-50 μm. If the conductive particles have an average particle size within such a range, the uniformity of the composition can be further improved, the coatability can be further improved, and the conductivity can be further increased. In the present invention, the average particle diameter means the 50% cumulative diameter (median diameter) in the volume-based particle size distribution, and can be measured with, for example, Microtrac MT330OEX manufactured by Nikkiso Co., Ltd.

The tap density of component (D) is preferably 1.0 to 7.0 g/cm ³ . The method for measuring the tap density conforms to JIS Z 2512:2012.

The filling amount of component (D) is preferably in the range of 50 to 99% by mass, more preferably 60 to 95% by mass, still more preferably 75 to 93% by mass, based on the total mass of the conductive silicone composition. is. Within such a range, a composition having excellent curability and handleability can be obtained, and sufficient electrical conductivity can be imparted to the cured product.

[(E) Component]
Component (E) in the conductive silicone composition of the present invention is an organic peroxide.

Organic peroxides have the effect of activating hydrosilylation catalysts having a bis(β-diketonato)platinum complex structure. Thereby, the curability can be improved while maintaining the storage stability of the composition. Although the organic peroxide is not particularly limited, alkyl peresters, peroxycarbonates, and dialkyl peroxides are preferable from the viewpoint of stability when coexisting with silver powder.

The one-hour half-life temperature of the organic peroxide in benzene is preferably 70 to 150°C, more preferably 80 to 140°C, still more preferably 90 to 130°C. Within such a range, the composition is excellent in storage stability and the activation of the hydrosilylation catalyst is sufficient.

Examples of organic peroxides include alkylperesters, peroxycarbonates, dialkylperoxides, diacylperoxides, peroxyketals, hydroperoxides and ketone peroxides. Alkyl peresters include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-amyl peroxypivalate, t -butylperoxypivalate, t-butylperoxydiethylacetate, t-amylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate and the like. Peroxycarbonates include bis(2-ethylhexyl) peroxydicarbonate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, dicetyl peroxydicarbonate, t-butylperoxyisopropyl carbonate, t-amyl peroxyisopropyl carbonate, 1,6-bis(t-butylperoxycarbonyloxy)hexane, bis(t-butylcyclohexyl)peroxydicarbonate and the like. Dialkyl peroxides include dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide and the like. Diacyl peroxides include isobutyroyl peroxide, lauroyl peroxide, benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide and the like. Peroxyketals include 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)butane, 2, 2-bis(t-amylperoxy)butane, n-butyl 4,4-bis(t-butylperoxy)pentanoate and the like. Examples of hydroperoxides include isopropylcumyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumyl hydroperoxide, t-butyl hydroperoxide, and t-amyl hydroperoxide. be done. Ketone peroxides include methyl ethyl ketone peroxide and acetylacetone peroxide.

The amount of the organic peroxide is preferably 100 to 5,000 parts by mass, more preferably 200 to 2,000 parts by mass, and still more preferably 100 parts by mass of the platinum atom in component (C). is 300 to 1,000 parts by mass. Within such a range, sufficient curability of the composition can be obtained, and foaming during curing can be suppressed.

An organic peroxide may be used individually by 1 type, and may use 2 or more types together.

[(F) Component]
Component (F) in the conductive silicone composition of the present invention is a compound having an oxacyclopropane structure. Component (F) is a component that imparts good adhesion to metals such as aluminum and copper to the conductive silicone composition of the present invention.

Specific examples of such (F) include allyl glycidyl ether, glycidyl (meth)acrylate, glycidyloxyethyl (meth)acrylate, 2,2-bis(4-glycidyloxyphenyl)propane, and triglycidyl isocyanurate. In addition to compounds having a glycidyl group such as ) compounds having an alicyclic epoxy structure such as methyl. From the viewpoint of reactivity with the polysiloxanes of components (A) and (B), component (F) is preferably an organosilicon compound such as silane or siloxane containing an oxacyclopropane structure. Examples of such compounds include those represented by the following structural formulas.

（なお、式中においてＭｅはメチル基を表す。）

(In the formula, Me represents a methyl group.)

The amount of component (F) to be blended is preferably in the range of 0.01 to 20 parts by mass, more preferably in the range of 0.1 to 10 parts by mass, per 100 parts by mass of component (A). If it is such a range, the adhesiveness with a metal will become more favorable.

(F) component may be used individually by 1 type, and may use 2 or more types together.

[(G) component]
Component (G) in the conductive silicone composition of the present invention is a carboxylic anhydride. Component (G) is a component that imparts good adhesion to metals such as aluminum and copper to the conductive silicone composition of the present invention.

The carboxylic acid anhydride may be either an intermolecular acid anhydride or an intramolecular acid anhydride, but is preferably an intramolecular acid anhydride having a tetrahydro-2,5-dioxofuran structure, and an acid anhydride having a phthalic anhydride structure. It is more preferable to be a thing. Examples of such intramolecular acid anhydrides include those represented by the following structural formulas.

The amount of component (G) is preferably 0.01 to 5.0 parts by mass per 1 part by mass of component (F) from the viewpoint of adhesion to metals and curability, and 0.05 to 3.0 parts by mass. parts is more preferable, and 0.1 to 2.0 parts by mass is even more preferable.

(G) component may be used individually by 1 type, and may use 2 or more types together.

[(H) Component]
To the conductive silicone composition of the present invention, at least one organosilicon compound selected from compounds represented by the following general formulas (3) to (5) and stereoisomers thereof is added as component (H). good too.

（式中、Ｒ^４は置換もしくは非置換の１価炭化水素基又は水素原子であり、Ｒ^５は置換又は非置換の１価炭化水素基であり、Ｒ^６は互いに同一又は異なっていても良い置換もしくは非置換の１価炭化水素基又はアルコキシ基である。）

(wherein R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group or hydrogen atom, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon group, and R ⁶ may be the same or different A substituted or unsubstituted monovalent hydrocarbon group or alkoxy group.)

Examples of substituted or unsubstituted monovalent hydrocarbon groups for R ⁴ , R ⁵ and R ⁶ include the same groups as those for R ² above, preferably having 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, More preferably, 1 to 8 unsubstituted or halogen-substituted monovalent hydrocarbon groups are mentioned, and a methyl group is particularly preferred.

The alkoxy group for R ⁶ preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 8 carbon atoms, and methoxy and ethoxy groups are particularly preferred.

These (H) components can be obtained, for example, by hydrosilylation reaction of (meth)acrylic acid ester and trialkoxysilane.

When component (H) is used, the amount to be blended is preferably 0.01 to 10 parts by mass per 1 part by mass of component (E). Within such a range, foaming during curing can be suppressed.

(H) component may be used individually by 1 type, and may use 2 or more types together.

[Other ingredients]
<Adhesion improver>
In addition to the above components (A) to (H), the conductive silicone composition of the present invention may contain other adhesion improvers to improve adhesion to resins and metals. From the viewpoint of imparting self-adhesiveness to the composition of the present invention, which is an addition reaction curing type, the adhesiveness improver includes organic silicon compounds such as silanes and siloxanes containing functional groups that impart adhesiveness, and non-silicone compounds. An organic compound or the like can be used.

Among the above adhesion improvers, examples of compounds containing an organosiloxane skeleton include those represented by the following structural formulas.

（なお、式中においてＭｅはメチル基を表す。）

(In the formula, Me represents a methyl group.)

Examples of non-silicone organic compounds include organic acid allyl ester compounds and allyl ether compounds represented by the following structural formulas.

Other non-silicone adhesive aids include organic titanium compounds, organic zirconium compounds, organic aluminum compounds, and the like.

Examples of organic titanium compounds include tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, titanium tetraacetylacetonate, diisopropoxytitanium bis(acetylacetonate), and the like.

Examples of organozirconium compounds include zirconium tetraethoxide, zirconium propoxide, zirconium butoxide, zirconium acetylacetonate, bisacetoxozirconium, and the like.

Examples of organoaluminum compounds include aluminum ethoxide, aluminum propoxide, aluminum butoxide, aluminum isopropoxide, aluminum acetylacetonate, and the like.

<Reinforcing material>
The electrically conductive silicone composition of the present invention may contain finely divided silica as a reinforcing agent to improve tensile strength, elongation and tear strength.

The fine powder silica preferably has a specific surface area (BET method) of 50 m ² /g or more, more preferably 50 to 400 m ² /g, particularly preferably 100 to 300 m ² /g. When the specific surface area is 50 m ² /g or more, sufficient reinforcing properties can be imparted to the cured product.

In the present invention, the finely divided silica may be a known one that has a specific surface area within the above range (50 m ² /g or more) and has been conventionally used as a reinforcing filler for silicone rubber. , fumed silica (dry silica), precipitated silica (wet silica), and the like. The finely divided silica may be used as it is, but in order to impart good fluidity to the composition, it may be added with methylchlorosilanes such as trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, dimethylpolysiloxane, hexamethyldisilazane, divinyl It is preferable to use one treated with an organic silicon compound such as tetramethyldisilazane, hexaorganodisilazane such as dimethyltetravinyldisilazane. Reinforcing silica may be used alone or in combination of two or more.

<Diluent>
The conductive silicone composition of the present invention can use non-reactive diluents. By using a diluent, the viscosity of the composition before curing can be reduced without impairing the electrical conductivity after curing, and workability can be enhanced. Examples of diluents include aromatic hydrocarbon solvents such as toluene and xylene, ester solvents such as ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, and propylene glycol methyl ether acetate, methyl ethyl ketone, cyclopentanone, Examples include ketone solvents such as methyl isobutyl ketone and aliphatic hydrocarbon solvents such as hexane, heptane, octane, isooctane and isododecane.

<Reaction control agent>
The conductive silicone composition of the present invention has good storage stability without using a reactivity control agent, but uses a known reaction control agent that has a reaction control effect on the addition reaction catalyst of component (C). You may Examples of the reaction control agent include phosphorus-containing compounds such as triphenylphosphine; nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine and benzotriazole; sulfur-containing compounds; acetylenic compounds; hydroperoxy compounds; be.

[Conductive silicone cured product]
The present invention provides a cured conductive silicone composition, which is a cured conductive silicone composition having a volume resistivity of 1.0×10 ⁻³ Ω·cm or less.

The cured product of the conductive silicone composition of the present invention preferably has a volume resistivity of 1.0×10 ⁻³ Ω·cm or less. Such a conductive silicone cured product has sufficient conductivity as well as flexibility and extensibility, and is useful for mounting electronic parts and elements on substrates and forming electronic circuits by printing. Become.

[Laminate]
The present invention provides a laminate comprising the cured conductive silicone material described above.

The conductive silicone composition of the present invention can form a highly conductive laminate, for example, by coating or printing on a substrate and then curing. The base material is not particularly limited, and examples include (meth) acrylic resins, epoxy resins, high-density polyethylene resins, low-density polyethylene resins, polypropylene resins, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyacrylonitrile resins, Organic materials such as polycarbonate resins, polyurethane resins, polyester resins, polyamide resins, polyimide resins, polyacetal resins, polyethylene oxide resins, polyetherimide resins, polyethersulfone resins, polyetheretherketone resins, polyphenylene sulfide resins, silicone resins, and alumina , zirconia, barium titanate, silicon nitride, aluminum nitride, silicon carbide, glass, and inorganic materials such as metals.

As a pretreatment for applying or printing the conductive silicone composition of the present invention, the various substrates described above may be subjected to surface treatment. Specific examples of surface treatment include irradiation with active energy rays such as ultraviolet rays, X-rays, γ-rays, α-rays, β-rays, and electron beams, plasma treatment, corona treatment, and ozone treatment.

[Application method]
The conductive silicone composition of the present invention can be applied, for example, onto a substrate by printing methods such as mesh screen printing, metal mask printing, gravure printing, offset printing, reverse offset printing, flexo printing, inkjet printing, roller coater, slit coater. , dispenser, and dipping.

[Manufacturing method of cured conductive silicone]
The conductive silicone composition of the present invention is preferably cured by heating at 80 to 120° C., especially 100 to 120° C. for 10 to 120 minutes. If it is such a range, hardening will fully progress and it can suppress that a composition becomes brittle.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The viscosity at 25°C was measured with a rotational viscometer, and the kinematic viscosity at 25°C was measured with an Ubbelohde viscometer or a Canon-Fenske viscometer.

[Examples 1 and 2, Comparative Examples 1 to 3]
Components (A) to (F) shown below and other components were mixed at the blending amounts shown in Table 1 using a rotation/revolution mixer (manufactured by THINKY Co., Ltd.) for 5 minutes to form a silicone composition. was prepared. In addition, the numerical value of each component in Table 1 shows a mass part. The silver powder filling rate is the mass percentage of the silver powder in the entire composition. In the following formulas, Vi represents a vinyl group and Me represents a methyl group.

[(A) Component]
a-1: both-terminal dimethylvinylsilyl group-blocked dimethylpolysiloxane (kinematic viscosity at 25° C. of 600 mm ² /s)
a-2: Organopolysiloxane having a weight average molecular weight of 4,500 represented by the following average formula.
(ViMe2SiO1/ ₂ ) _0.07 ( _{Me3SiO1 /2 ) 0.39} ( _SiO4/2 ) _0.54

（式中、括弧内のシロキサン単位の配列順は不定である。） [(B) Component]
b-1: Organohydrogenpolysiloxane represented by the following formula.

(In the formula, the sequence of the siloxane units in parentheses is undefined.)

[(C) component]
c-1: Bis(1,3-propanedionato)platinum complex in butyl carbitol acetate solution (containing 0.5% by mass as platinum atoms) (manufactured by Umicore)

[(D) Component]
d-1: silver powder with a volume median diameter of 5.8 μm and a tap density of 5.3 g/cm ³

[(E) component]
e-1: 70 mass% citric acid tributyl acetate solution of 1,6-bis(t-butylperoxycarbonyloxy)hexane (manufactured by Kayaku Nourion Co., Ltd., trade name: Kayalen 6-70, 0.2 in benzene 1 hour half-life temperature 115°C in mol/L)

[(F) component]
f-1: a compound represented by the following formula

[(G) Component]
g-1: 3,3',4,4'-benzophenonetetracarboxylic dianhydride

[(H) Component]
h-1: a compound represented by the following formula

The properties of the conductive silicone composition and its cured product were evaluated as follows. Table 1 shows the results.

[Shear adhesive strength]
Each of the silicone compositions of Examples 1 and 2 and Comparative Examples 1 to 3 was sandwiched between two 0.3 mm thick aluminum plates or two copper plates so that the thickness was 1 mm and the adhesive surface was 25 mm × 10 mm, and the temperature was 120°C. and heated for 1 hour to prepare a test piece. The obtained test piece was subjected to a tensile shear bond strength test according to JIS-K6850:1999.

[State of broken part]
After the shear adhesion test, the state of the fractured portion (cohesive failure/interfacial peeling, and degree of foaming, if any) was visually observed. In addition, when the state of the fractured portion is cohesive failure, it is suggested that the adhesive strength with the metal plate is higher than in the case of interfacial peeling.

[Volume resistivity]
Each of the silicone compositions of Examples 1 and 2 and Comparative Examples 1 to 3 was squeegee-coated on a slide glass to a thickness of 150 μm and heated in an oven at 120° C. for 1 hour. The obtained measurement sample was subjected to volume resistivity measurement by the four-probe method using Loresta GX manufactured by Mitsubishi Chemical Analytech.

As shown in Table 1, in Examples 1 and 2, the adhesion to aluminum and copper is also good. Furthermore, in Example 1 using the composition to which the (H) component was added, foaming during curing was suppressed.

On the other hand, in Comparative Examples 1 and 2, in which compositions containing no acid anhydride were used, adhesion to aluminum was good, but adhesion to copper was poor. Furthermore, in Comparative Example 3 using a composition containing no compound having an oxacyclopropane structure, adhesion to both aluminum and copper was insufficient.

As described above, the conductive silicone composition of the present invention is a highly conductive material with good adhesion to metals such as aluminum and copper.

It should be noted that the present invention is not limited to the above embodiments. The above-described embodiment is an example, and any device having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect is the present invention. included in the technical scope of

Claims (9)

(A) an organopolysiloxane having at least two groups per molecule having a hydrosilylation-reactive carbon-carbon unsaturated bond;
(B) an organohydrogenpolysiloxane having at least two SiH groups per molecule;
(C) a bis(β-diketonato)platinum complex,
(D) conductive particles;
(E) an organic peroxide,
A conductive silicone composition comprising (F) a compound having an oxacyclopropane structure and (G) a carboxylic anhydride. The number of SiH groups in the component (B) is 0.5 to 10.0 per hydrosilylation-reactive carbon-carbon unsaturated bond in the component (A). The conductive silicone composition of claim 1, characterized in that. 3. The conductive silicone composition according to claim 1, wherein said component (D) is silver powder. 4. The conductive silicone composition according to any one of claims 1 to 3, wherein the content of component (D) is 50 to 99 mass% of the total mass of the composition. 5. The conductive material according to any one of claims 1 to 4, wherein the component (E) is an organic peroxide having a peroxycarbonate structure, an alkylperester structure, or a dialkylperoxide structure. silicone composition. 6. The conductive silicone composition according to any one of claims 1 to 5, wherein the component (G) is an intramolecular carboxylic acid anhydride having a tetrahydro-2,5-dioxofuran structure. Any one of claims 1 to 6, further comprising (H) at least one organosilicon compound selected from compounds represented by the following general formulas (3) to (5) and stereoisomers thereof. The conductive silicone composition according to claim 1.

(wherein R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group or hydrogen atom, R ⁵ is a substituted or unsubstituted monovalent hydrocarbon group, and R ⁶ may be the same or different A substituted or unsubstituted monovalent hydrocarbon group or alkoxy group.) A cured product of the conductive silicone composition according to any one of claims 1 to 7, characterized by having a volume resistivity of 1.0 × 10 ^-3 Ω·cm or less. conductive silicone cured product. A laminate comprising the conductive silicone cured product according to claim 8 .