Conductive silicone materials and uses

• US 9,428,680 B2
• Filed: 03/11/2014
• Issued: 08/30/2016
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Dow Silicones Corporation (Dow, Inc.)
• Original Assignee: Dow, Inc.
• Inventors: Zambova, Adriana Petkova
• Primary Examiner(s): Loewe, Robert S
• Application Number:
  US14/774,401
• Publication Number:
  US 20160024358A1
• Time in Patent Office: 903 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C08G 77/12 containing silicon bound to hydrogen C08G77/045 takes precedence
• CPC Class Codes: C08G 77/14 containing silicon bound to oxygen-containing groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: C08K 2003/0806 Silver
• CPC Class Codes: C08K 2003/085 Copper
• CPC Class Codes: C08K 2201/001 Conductive additives
• CPC Class Codes: C08K 3/041 Carbon nanotubes
• CPC Class Codes: C08K 3/08 Metals
• CPC Class Codes: C08K 3/36 Silica
• CPC Class Codes: C08K 5/56 Organo-metallic compounds, i.e. organic compounds containing a metal-to-carbon bond
• CPC Class Codes: C08K 9/10 Encapsulated ingredients
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C09J 183/04 Polysiloxanes
• CPC Class Codes: C09K 5/08 Materials not undergoing a change of physical state when used C09K5/16, C09K5/20 take precedence
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 23/04 : characterised by the shape of the container or parts, e.g. caps, walls
• CPC Class Codes: H01L 23/3737 : Organic materials with or without a thermoconductive filler
• CPC Class Codes: H01L 23/42 : Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H05K 3/0061 : onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20
• CPC Class Codes: H05K 7/20409 : Outer radiating structures on heat dissipating housings, e.g. fins integrated with the housing

Abstract

A curable silicone composition comprising a curable organosiloxane composition, copper-silver (Cu—Ag) core-shell particles, and hydrocarbon vehicle; the curable silicone composition being characterizable by: a concentration of the Cu—Ag core-shell particles of from 70 to 89 weight percent and a total concentration of silver of from 7.0 to 12 weight percent, all based on weight of the curable silicone composition; wherein the curable silicone composition has a concentration of the Cu—Ag core-shell particles and hydrocarbon vehicle such that the curable silicone composition remains curable to a conductive silicone material having a concentration of the Cu—Ag core-shell particles of from 88.0 to 92 weight percent and having a volume resistivity of less than 0.020 Ohm-centimeter measured according to Volume Resistivity Test Method, and a thermal conductivity of greater than or equal to 2.9 Watts per meter*Kelvin (W/(m*K)) measured according to Thermal Properties Test Method.

Claims

1. A curable silicone composition comprising a curable organosiloxane composition, copper-silver (Cu—

Ag) core-shell particles, a mechanical thixotropic filler that is carbon nanotubes, and hydrocarbon vehicle;

the curable silicone composition being characterized by;

a concentration of the Cu—

Ag core-shell particles of from 80 to 89 weight percent and a total concentration of silver of from 7 to 12 weight percent, all based on weight of the curable silicone composition;

wherein the curable silicone composition has a concentration of the Cu—

Ag core-shell particles and hydrocarbon vehicle such that the curable silicone composition remains curable to a conductive silicone material having a concentration of the Cu—

Ag core-shell particles of from 88.0 to 92 weight percent and having a volume resistivity of less than 0.020 Ohm-centimeter measured according to Volume Resistivity Test Method and a thermal conductivity of greater than or equal to 2.9 Watts per meter*Kelvin measured according to Thermal Properties Test Method;

wherein the curable silicone composition is characterized by a Thixotropic Index(η

₁/η

₁₀) of from 3 to 10.

2. A curable silicone composition comprising a blend of the following ingredients:

a hydrocarbon vehicle at a concentration of from 1 to 15 weight percent based on weight of the curable silicone composition, wherein the hydrocarbon vehicle is characterized by a boiling point from 100 to 360 degrees Celsius;

a curable organosiloxane composition at a concentration of from 8 to 16 weight percent based on weight of the curable silicone composition;

Cu—

Ag core-shell particles at a concentration of from 70 to 89 weight percent based on weight of the curable silicone composition; and

a mechanical thixotropic filler that is carbon nanotubes;

wherein the total concentration of silver is from 9 to 12 weight percent based on weight of the curable silicone composition;

wherein the curable silicone composition has a concentration of the Cu—

Ag core-shell particles and hydrocarbon vehicle such that the curable silicone composition remains curable to a conductive silicone material having a concentration of the Cu—

Ag core-shell particles of from 88.0 to 92 weight percent and having a volume resistivity of less than 0.020 Ohm-centimeter measured according to Volume Resistivity Test Method and a thermal conductivity of greater than or equal to 2.9 Watts per meter*Kelvin (W/(m*K)) measured according to Thermal Properties Test Method; and

wherein the curable silicone composition is characterized by a Thixotropic Index(η

₁/η

₁₀) of from 3 to 10.

3. The curable silicone composition of claim 2 characterized by a volume resistivity less than 0.0010 Ohm-centimeter measured according to Volume Resistivity Test Method and a thermal conductivity of greater than or equal to 3 Watts per meter*Kelvin measured according to Thermal Properties Test Method.

4. The curable silicone composition of claim 2 characterized by the following limitations:

wherein the hydrocarbon vehicle is an alkanes mixture of different molecules wherein the lowest boiling alkanes molecules have an initial boiling point greater than 150 degrees Celsius and the highest boiling alkanes molecules have an end boiling less than 300 degrees Celsius and the hydrocarbon vehicle is at a concentration of from 1 to 15 weight percent based on weight of the curable silicone composition;

wherein the curable organosiloxane composition comprises at least one diorganosiloxane compound, a catalyst, and an adhesion promoter;

wherein the at least one diorganosiloxane compound has on average per molecule at least 1 reactive moiety, wherein each reactive moiety independently is an alkenyl moiety, Si—

H moiety, Si—

OH moiety, Si—

OR moiety, wherein R is (C₁-C₁₀)hydrocarbyl, —

C(O)(C₁-C₁₀)hydrocarbyl, or —

N═

CR¹R², wherein each of R¹ and R² independently is (C₁-C₁₀)hydrocarbyl or R¹ and R² are taken together to form a (C₂-C₁₀)hydrocarbylene; and

wherein the at least one diorganosiloxane compound is at least 50 weight percent of the curable organosiloxane composition;

wherein the Cu—

Ag core-shell particles are unsintered and are at a concentration of from 75 to 89 weight percent based on weight of the curable silicone composition;

wherein the total concentration of silver is from 9.1 to 12 weight percent based on weight of the curable silicone composition;

wherein the mechanical thixotropic filler is carbon nanotubes, wherein the carbon nanotubes are at a concentration of from 0.1 to 5.0 weight percent based on weight of the curable silicone composition; and

wherein the curable silicone composition is characterized by a volume resistivity less than 0.0010 Ohm-centimeter measured according to Volume Resistivity Test Method and a thermal conductivity of greater than or equal to 4 Watts per meter*Kelvin measured according to Thermal Properties Test Method.

5. The curable silicone composition of claim 4, characterized by the following limitations:

wherein the hydrocarbon vehicle is an alkanes mixture;

wherein the curable organosiloxane composition comprises at least one diorganosiloxane compound, at least one organohydrogensilicon compound, a hydrosilylation catalyst, and an epoxy-functional adhesion promoter;

wherein the at least one diorganosiloxane compound has on average per molecule at least 1 alkenyl moiety and the organohydrogensilicon compound has on average per molecule at least 1 Si—

H moiety; and

wherein the at least one diorganosiloxane compound is from 60 to 80 wt % of the curable organosiloxane composition;

wherein the Cu—

Ag core-shell particles are at a concentration of from 79.5 to 86.4 weight percent based on weight of the curable silicone composition;

wherein the total concentration of silver is from 9.5 to 12 weight percent based on weight of the curable silicone composition; and

wherein the carbon nanotubes are single-walled carbon nanotubes, multi-walled carbon nanotubes, derivatized carbon nanotubes or a combination of any two or more of the single-walled carbon nanotubes, multi-walled carbon nanotubes, and derivatized carbon nanotubes; and

the concentration of carbon nanotubes is from 0.2 to 2 weight percent based on weight of the curable silicone composition.

6. The curable silicone composition of claim 5, characterized by the following limitations:

wherein the alkanes mixture is an isoalkanes mixture comprising at least two of (C₉-C₁₂)isoalkanes, at least two of (C₁₂-C₁₆)isoalkanes or at least two of (C₁₆-C₂₂)isoalkanes and the hydrocarbon vehicle is at a concentration of from 1.5 to 15 weight percent based on weight of the curable silicone composition;

wherein the curable organosiloxane composition is hydrosilylation curable and comprises the at least one diorganosiloxane compound, the at least one trimethylsiloxy-terminated dimethyl organohydrogensilicon compound, a microencapsulated hydrosilylation catalyst, and a bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane;

wherein the alkenyl of the diorganosiloxane is vinyl and the at least one diorganosiloxane compound has on average per molecule at least 1.1 vinyl moieties, the at least one trimethylsiloxy-terminated dimethyl organohydrogensilicon compound is and has on average per molecule at least 1.1 Si—

H moieties, or the least one diorganosiloxane compound has on average per molecule at least 1.1 vinyl moieties and the at least one organohydrogensilicon compound has on average per molecule at least 1.1 Si—

H moieties;

wherein the at least one diorganosiloxane compound having vinyl moieties is from 70 to 75 wt % of the curable organosiloxane composition;

wherein the at least one trimethylsiloxy-terminated dimethyl organohydrogensilicon compound is from 1 to 5 weight percent, the microencapsulated hydrosilylation catalyst is from 10 to 15 weight percent, and the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane is from 5 to 10 weight percent, and together the organohydrogensilicon compound, microencapsulated hydrosilylation catalyst, and the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane are from 20 to 30 wt % of the curable organosiloxane composition;

wherein the Cu—

Ag core-shell particles are at a concentration of from 79.9 to 86.0 weight percent based on weight of the curable silicone composition;

wherein the total concentration of silver is from 10.0 to 11.0 weight percent based on weight of the curable silicone composition; and

wherein the carbon nanotubes are multi-walled carbon nanotubes at a concentration of from 0.50 to 1.5 weight percent based on weight of the curable silicone composition; and

wherein the curable silicone composition is characterized by a volume resistivity less than 0.00090 Ohm-centimeter measured according to Volume Resistivity Test Method and a thermal conductivity of greater than or equal to 5 Watts per meter*Kelvin measured according to Thermal Properties Test Method.

7. A conductive silicone material that is a product of curing the curable silicone composition of claim 2, wherein the conductive silicone material is characterized by a concentration of the Cu—

Ag core-shell particles of from 88.0 to 92 weight percent, a volume resistivity of less than 0.0010 Ohm-centimeter measured according to Volume Resistivity Test Method, and a thermal conductivity of greater than or equal to 2.9 Watts per meter*Kelvin measured according to Thermal Properties Test Method;

wherein some of the hydrocarbon vehicle remains in the conductive silicone adhesive after curing such that the conductive silicone adhesive has less than 5 weight percent of the hydrocarbon vehicle.

8. The conductive silicone material of claim 7 further characterized by an elongation at break of at least 50 percent measured according to the Tensile Strength Test Method.

9. An electrical device sequentially comprising a heat generating electrical component, the conductive silicone material of claim 7 disposed in thermal communication and contact with the heat generating electrical component, and a heat dissipator in thermal communication and contact with the conductive silicone material.

10. An electronic device comprising:

a first electronic component,

a second component, and

the conductive silicone material of claim 7 as a thermal interface material (TIM), wherein the TIM is interposed between and in independent thermal communication with the first electronic component and the second component.

11. A method of manufacturing an electrical device comprising first and second components having surfaces and a conductive silicone material, the method comprising depositing the curable silicone composition of claim 2 onto one or both surfaces of the first and second components, and orienting the first and second components so that their surfaces are opposing each other to give a preassembly comprising the curable silicone composition disposed between and in physical contact with the opposing surfaces of the first and second components;

and curing the curable silicone composition between the opposing surfaces of the first and second components to give an electrical device comprising the first and second components and a conductive silicone material disposed between and in adhering operative contact with the opposing surfaces of the first and second components such that the first and second components are disposed for thermal operative communication with each other via the conductive silicone material, wherein the conductive silicone material is characterized by a concentration of the Cu—

Ag core-shell particles of from 88.0 to 92 weight percent, a volume resistivity of less than 0.020 Ohm-centimeter measured according to Volume Resistivity Test Method, and a thermal conductivity of greater than or equal to 2.9 Watts per meter*Kelvin measured according to Thermal Properties Test Method, and wherein the first component is a heat generating electrical component and the second component is a heat dissipator;

wherein some of the hydrocarbon vehicle remains in the conductive silicone adhesive after curing such that the conductive silicone adhesive has less than 5 weight percent of the hydrocarbon vehicle.

12. A method of preparing a thermally conductive material, the method comprising curing the curable silicone composition of claim 2 to give a product of curing thereof as a curable thermally conductive material having a concentration of the Cu—

Ag core-shell particles of from 88.0 to 92 weight percent and having a thermal conductivity of greater than or equal to 2.9 W/(m*K) measured according to Thermal Properties Test Method;

wherein some of the hydrocarbon vehicle remains in the conductive silicone adhesive after curing such that the conductive silicone adhesive has less than 5 weight percent of the hydrocarbon vehicle.

13. A curable silicone composition comprising a blend of the following ingredients:

an isoalkanes mixture comprising at least three of (C₁₂-C₁₆)isoalkanes and wherein the lowest boiling isoalkanes molecules have an initial boiling point of greater than 210 degrees Celsius and the highest boiling isoalkanes molecules have an end boiling point of less than 270 degrees Celsius and the hydrocarbon vehicle is at a concentration of from 4.5 to 12 weight percent based on weight of the curable silicone composition;

a hydrosilylation-curable polydimethylsiloxane composition comprising at least one vinyl-functional polydimethylsiloxane compound having on average per molecule at least 1 vinyl moieties, at least one trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound having on average per molecule at least 1.1 Si—

H moieties, a microencapsulated platinum hydrosilylation catalyst, and bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane, and bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane; and

wherein the vinyl-functional polydimethylsiloxane compound is from 70 to 75 weight percent, the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound is from 1 to 5 weight percent, the microencapsulated hydrosilylation catalyst is from 10 to 15 weight percent, the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane is from 1 to 10 weight percent, and the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane is from 0 to 7 weight percent, all of the curable polydimethylsiloxane composition; and

wherein together the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound, microencapsulated hydrosilylation catalyst, and the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane, and bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane are from 20 to 30 wt % of the curable organosiloxane composition;

Cu—

Ag core-shell particles are at a concentration of from 70 to 89 weight percent based on weight of the curable silicone composition;

wherein the total concentration of silver is from 7.5 to 12.0 weight percent based on weight of the curable silicone composition; and

carbon nanotubes at a concentration of from 0.50 to 1.2 weight percent based on weight of the curable silicone composition; and

wherein the curable silicone composition has a concentration of the Cu—

Ag core-shell particles and hydrocarbon vehicle such that the curable silicone composition is curable to a cured silicone material

characterized by a concentration of the Cu—

Ag core-shell particles of from 88.4 to 90.4 weight percent, a volume resistivity less than 0.00090 Ohm-centimeter measured according to Volume Resistivity Test Method, and a thermal conductivity of greater than or equal to 5 Watts per meter*Kelvin measured according to Thermal Properties Test Method.

14. The curable silicone composition of claim 13, wherein the curable silicone composition is characterized by a Thixotropic Index(η

₁/η

₁₀) of from 3 to 10.

15. A curable silicone composition comprising a blend of the following ingredients:

a hydrocarbon vehicle at a concentration of from 1 to 15 weight percent based on weight of the curable silicone composition, wherein the hydrocarbon vehicle is characterized by a boiling point from 100 to 360 degrees Celsius;

a curable organosiloxane composition at a concentration of from 8 to 16 weight percent based on weight of the curable silicone composition;

Cu—

Ag core-shell particles at a concentration of from 70 to 89 weight percent based on weight of the curable silicone composition; and

a mechanical thixotropic filler that is carbon nanotubes;

wherein the total concentration of silver is from 9 to 12 weight percent based on weight of the curable silicone composition;

wherein the curable silicone composition has a concentration of the Cu—

Ag core-shell particles and hydrocarbon vehicle such that the curable silicone composition remains curable to a conductive silicone material having a concentration of the Cu—

Ag core-shell particles of from 88.0 to 92 weight percent and having a volume resistivity of less than 0.00090 Ohm-centimeter measured according to Volume Resistivity Test Method and a thermal conductivity of greater than or equal to 9 Watts per meter*Kelvin (W/(m*K)) measured according to Thermal Properties Test Method.

16. The curable silicone composition of claim 15, wherein the curable silicone composition is characterized by a Thixotropic Index(η

₁/η

₁₀) of from 3 to 10.