JP2015065330A - Heat dissipation sheet, sheet-like cured product with high heat dissipation, and method for application of heat dissipation sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat dissipation sheet which is easy to be handled since there is no stickiness on the surface, which has excellent self-adhesiveness and electrical insulation properties, and which is excellent even in heat dissipation, and also to provide a cured product thereof.SOLUTION: Disclosed is a heat dissipation sheet in which, on both surfaces of a metal layer, a solid or semisolid addition-curable silicon resin composition is coated at normal temperature containing a thermal conductive filler. The surface of the heat dissipation sheet has non-stickiness.

Description

  The present invention relates to a heat radiating sheet, a highly heat radiating sheet-like cured product obtained by heating and curing the heat radiating sheet, and a method of using the heat radiating sheet.

  Conventionally, when an electronic component that generates a large amount of heat, such as a CPU, GPU, or power module, is attached to a heat sink, the heat used to efficiently transfer the heat generated in the electronic component to the heat sink by eliminating gaps between the components. As a conductive material, a material obtained by mixing a thermal conductive powder with a silicone resin as disclosed in Patent Document 1 into a sheet is widely used.

  However, for example, a thermally conductive silicone rubber sheet as shown in Patent Document 2 is easy to handle, but because it uses a heat-cured rubber sheet, it can adhere to the unevenness of the surface of an electronic component or heat sink. It is difficult to sufficiently fill these gaps, and it is difficult to efficiently release heat to the outside.

  In order to solve this problem, Patent Document 3 proposes a heat-dissipating sheet having adhesive layers on both sides of the sheet, but it is difficult to handle such as sticking the adhesive surfaces together, and at the interface between the sheet and the adhesive layer. There was a problem that contact thermal resistance occurred.

  In addition, as shown in Patent Document 4 and Patent Document 5, a heat dissipation sheet in which soft silicone resin is arranged on both sides of a metal or ceramic reinforcing material has been proposed, but it solves the problems of adhesiveness and contact thermal resistance. It has not been done.

Japanese Patent Laid-Open No. 2005-54099 Japanese Patent Laid-Open No. 11-209618 JP 2005-228955 A JP 7-14950 A JP 2004-39829 A

  The present invention has been made in view of the above problems, and since it has no adhesiveness on the surface, it is easy to handle, has excellent self-adhesiveness and electrical insulation, and has excellent heat dissipation and its heat dissipation sheet It aims at providing hardened | cured material.

In order to solve the above problems, in the present invention,
A heat radiating sheet in which a solid or semi-solid addition-curable silicone resin composition containing a thermally conductive filler is coated on both surfaces of a metal layer, and the surface of the heat radiating sheet is non-adhesive A heat dissipating sheet is provided.

  Such a heat dissipation sheet of the present invention is easy to handle because there is no stickiness on the surface, and because it has a metal layer as a core material, it has excellent heat dissipation, and the silicone resin has excellent self-adhesiveness The contact heat resistance at the interface with the metal can be suppressed, and the heat dissipation sheet is excellent in electrical insulation.

At this time, the addition-curable silicone resin composition is
(A) R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where R ¹ , R ² , And R ³ independently represents any of a hydroxyl group, a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and a phenyl group, R ⁴ independently represents a vinyl group or an allyl group, and a is 0, 1 or 2 , B is 1 or 2, and a + b is 2 or 3.)
An organopolysiloxane having a resin structure including a structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions thereof is 10 to 50;
(B) R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _c H _d SiO _{(4-cd) / 2} units (where R ¹ , R ² and R ³ is independently as described above, c is 0, 1 or 2, d is 1 or 2, and c + d is 2 or 3.
Resin-structured organohydrogenpolysiloxane comprising a structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions thereof is 10 to 50: in the component (A) The amount of hydrogen atoms bonded to silicon atoms in component (B) relative to the total of vinyl groups and allyl groups is 0.1 to 4.0 by molar ratio,
(C) Platinum group metal catalyst: It contains a curing effective amount, and (D) a thermally conductive filler, and is preferably solid or semi-solid at room temperature when uncured.

  If such an addition curable silicone resin composition is used, it becomes a heat conductive addition curable silicone resin composition having no adhesiveness and more excellent in self-adhesiveness and electrical insulation. Although it is easy to handle, it becomes a heat-dissipating sheet with better heat dissipation, self-adhesiveness, and electrical insulation.

  Moreover, at this time, the said addition curable silicone resin composition contains 100-1500 mass parts of said (D) heat conductive fillers with respect to a total of 100 mass parts of said (A)-(C) component. It is preferable that

  Since such an addition-curable silicone resin composition is an addition-curable silicone resin composition with more excellent thermal conductivity, a heat-dissipating sheet using this composition is easier to handle and more heat-dissipating. Excellent heat dissipation sheet.

The electrical resistivity at 20 ° C. of the (D) thermally conductive filler is preferably 1 × 10 ¹⁰ Ω · cm or more.

  If the thermally conductive filler has such an electrical resistivity, the addition-curable silicone resin composition exhibits good electrical insulation, and the resulting heat dissipation sheet and its cured product also have good electrical insulation. Indicates.

  Moreover, it is preferable at this time that the said metal layer consists of a metal chosen from aluminum, copper, silver, and those alloys.

  If it is such a metal layer, since it has high heat conductivity, it will become a heat radiating sheet excellent in heat dissipation.

  Furthermore, in this invention, the highly heat radiating sheet-like hardened | cured material which is the heat-cured material of the said heat radiating sheet is provided.

  If it is such a highly heat-dissipating sheet-like cured product, it becomes a highly heat-dissipating sheet-like cured product excellent in self-adhesion, electrical insulation, and heat dissipation.

  At this time, it is preferable that the type D durometer hardness described in JIS K 6253 of the highly heat-dissipating sheet-like cured product is 30 or more.

  If it is such hardness, it will become a highly heat-radiation sheet-like hardened | cured material which has sufficient intensity | strength.

  Moreover, it is preferable at this time that the surface of the said high heat dissipation sheet-like hardened | cured material is non-adhesive.

  Such a highly heat-dissipating sheet-like cured product has a non-adhesive surface and is easy to handle.

  At this time, it is preferable that the highly heat-radiating sheet-like cured product has a thermal conductivity of 1.5 W / m · K or more.

  If it has such heat conductivity, it will become a highly heat-radiation sheet-like hardened | cured material more excellent in heat dissipation.

  Furthermore, the present invention provides a method for using a heat dissipation sheet that is used after being heat-cured after the heat dissipation sheet is in close contact with an electronic component.

  As described above, the heat dissipation sheet of the present invention can be used after being heat-cured after being brought into close contact with an electronic component.

  As described above, the heat-dissipating sheet of the present invention is a metal having a high thermal conductivity and a heat-conductive addition-curable silicone resin composition having no adhesiveness and having excellent self-adhesiveness and electrical insulation. By arranging on both sides of the layer, the surface is not sticky and easy to handle, and because it has good self-adhesiveness, the contact thermal resistance with the metal layer that is the core material is suppressed, and the heating element and heat sink Since a metal layer having a high thermal conductivity can be used as a core material, the space sheet can be filled without any gaps, and the heat dissipation sheet is excellent in heat dissipation and also in electrical insulation. For this reason, the heat-radiation sheet of this invention is suitable as a heat conductive material for efficiently transmitting the heat generated in the electronic component to the heat sink.

Hereinafter, the present invention will be described in more detail.
As described above, it has been difficult for the conventional heat dissipation sheet to achieve both workability and heat dissipation.
As a result of intensive studies to solve the above problems, the present inventors are made of a metal in which an addition-curable silicone resin composition that is solid or semisolid at room temperature is arranged on both sides, and the surface is non-adhesive The present invention has been completed by finding that the above-mentioned problems can be solved by a heat dissipation sheet.

  That is, the present invention is a heat dissipation sheet in which a solid or semisolid addition-curable silicone resin composition containing a thermally conductive filler is coated on both surfaces of a metal layer, It is a heat dissipation sheet whose surface is non-adhesive.

Hereinafter, the present invention will be described more specifically, but the present invention is not limited thereto.
In the present specification, “normal temperature” means an ambient temperature in a normal state, usually a temperature in the range of 15 to 30 ° C., and typically 25 ° C.

The “solid” composition of the present invention has plasticity.
“Semi-solid” means a state of a substance that has plasticity and can retain the shape for at least 1 hour, preferably 8 hours or more when formed into a specific shape. Thus, for example, a flowable material having a very high viscosity at room temperature is essentially flowable, but changes to the applied shape in a short time of at least 1 hour (ie, breakage) due to the very high viscosity. ) Cannot be seen with the naked eye, the substance is in a semi-solid state.

The addition-curable silicone resin composition used for the heat dissipation sheet of the present invention contains a thermally conductive filler and is solid or semi-solid at room temperature.
Such an addition-curable silicone resin composition is not particularly limited,
(A) R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where R ¹ , R ² , And R ³ independently represents any of a hydroxyl group, a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and a phenyl group, R ⁴ independently represents a vinyl group or an allyl group, and a is 0, 1 or 2 , B is 1 or 2, and a + b is 2 or 3.)
An organopolysiloxane having a resin structure including a structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions thereof is 10 to 50;
(B) R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _c H _d SiO _{(4-cd) / 2} units (where R ¹ , R ² and R ³ is independently as described above, c is 0, 1 or 2, d is 1 or 2, and c + d is 2 or 3.
Resin-structured organohydrogenpolysiloxane comprising a structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions thereof is 10 to 50: in the component (A) The amount of hydrogen atoms bonded to silicon atoms in component (B) relative to the total of vinyl groups and allyl groups is 0.1 to 4.0 by molar ratio,
(C) Platinum group metal catalyst: It contains a curing effective amount, and (D) a thermally conductive filler, and is preferably solid or semi-solid at room temperature when uncured.

-(A) Resin-structured organopolysiloxane-
The organopolysiloxane having a resin structure (that is, a three-dimensional network structure), which is an important component (A) of the addition-curable silicone resin composition used in the heat dissipation sheet of the present invention, is R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where R ¹ , R ² , and R ³ are hydroxyl, methyl, ethyl, propyl A group, a cyclohexyl group, or a phenyl group, R ⁴ independently represents a vinyl group or an allyl group, a is 0, 1 or 2, b is 1 or 2, and a + b is 2 or 3.) ,
A structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions is 10 to 50, preferably 15 to 45, more preferably 20 to 35, is partially Is an organopolysiloxane having a resin structure.

If the number of R ² ₂ SiO _2/2 units is 10 or more, it is preferable because the composition loses its plasticity and becomes difficult to handle, and the cured product when the composition is cured does not become brittle. . Further, if the R ² ₂ SiO _2/2 unit is 50 or less, the composition cannot maintain a solid or semi-solid state, and the cured product does not become too soft. This is preferable because workability does not deteriorate.

（ここで、ｍは１０〜５０の整数）
で表される直鎖状ジオルガノポリシロキサン連鎖構造を意味する。 The structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions thereof is 10 to 50 is the following general formula (1):

(Where m is an integer from 10 to 50)
The linear diorganopolysiloxane chain structure represented by these is meant.

(A) At least a part of the entire R ² ₂ SiO _2/2 unit present in the organopolysiloxane of the component, preferably 50 mol% to 100 mol%, particularly 80 mol% to 100 mol% is contained in the molecule. It is preferable to form a chain structure represented by the general formula (1).

In the molecule of component (A), the R ² ₂ SiO _2/2 unit works to stretch the polymer molecule in a straight line, and the R ¹ SiO _3/2 unit branches the polymer molecule or forms a three-dimensional network. Let R ³ _a R ⁴ _b SiO _{(4-ab) / 2} R ⁴ (independently a vinyl group or an allyl group) in the unit is R ³ _c H _d SiO _(4- It serves to cure the composition of the present invention by hydrosilylation addition reaction with hydrogen atoms (ie, SiH groups) bonded to _{cd) / 2} units of silicon atoms.

(A) The molar ratio of the three essential siloxane units constituting the component, that is, R ¹ SiO _3/2 units: R ² ₂ SiO _2/2 units: R ³ _a R ⁴ _b SiO _{(4-ab) / 2} unit has a molar ratio of 90 to 24:75 to 9:50 to 1, particularly 70 to 28:70 to 20:10 to 2 (provided that the total is 100). preferable.

  Moreover, when the polystyrene conversion weight average molecular weight of this (A) component by gel permeation chromatography (GPC) exists in the range of 3,000-1,000,000, especially 10,000-100,000, workability | operativity is. From the viewpoint of curability and the like.

In addition, suppose that the weight average molecular weight mentioned in this invention refers to the weight average molecular weight which used polystyrene by the gel permeation chromatography (GPC) measured on the following conditions as a reference material.
[Measurement condition]
Developing solvent: THF
Flow rate: 0.6mL / min
Detector: Differential refractive index detector (RI)
Column: TSK Guardcolom SuperH-L
TSKgel SuperH4000 (6.0 mm ID × 15 cm × 1)
TSKgel Super H3000 (6.0 mm ID × 15 cm × 1)
TSKgel SuperH2000 (6.0 mm ID × 15 cm × 2)
(Both manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Sample injection volume: 20 μL (0.5% by weight THF solution)

  Such an organopolysiloxane having a resin structure is obtained by combining compounds as raw materials for each unit so that the above three kinds of siloxane units have a required molar ratio in the produced polymer, for example, in the presence of a catalyst such as an acid. It can be synthesized by carrying out cohydrolytic condensation.

Here, as raw materials for the R ¹ SiO _3/2 unit, MeSiCl ₃ , EtSiCl ₃ , PhSiCl ₃ (hereinafter Me represents a methyl group, Et represents an ethyl group, Ph represents a phenyl group), n-propyltrichlorosilane, Examples include chlorosilanes such as cyclohexyltrichlorosilane, alkoxysilanes such as methoxysilane corresponding to these chlorosilanes, and the like.

（ここで、ｍ１＝８〜４８の整数（平均値）、ｍ２＝５〜４８の整数（平均値）、ｍ３＝０〜４３の整数（平均値）、ただし、ｍ２＋ｍ３は８〜４８の整数）
等を例示することができる。 As a raw material of R ² ₂ SiO _2/2 unit,

(Where m1 = integer of 8-48 (average value), m2 = integer of 5-48 (average value), m3 = 0-43 (average value), where m2 + m3 is an integer of 8-48
Etc. can be illustrated.

Further, R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units are R ³ R ⁴ SiO _2/2 units, R ³ ₂ R ⁴ SiO _1/2 units, and R ⁴ ₂ SiO _2/2 units. , And R ³ R ⁴ ₂ SiO _1/2 means one siloxane unit or a combination of two or more siloxane units. The raw materials include chlorosilanes such as Me ₂ ViSiCl, MeViSiCl ₂ , Ph ₂ ViSiCl, PhViSiCl ₂ (hereinafter Vi represents a vinyl group), alkoxysilanes such as methoxysilane corresponding to each of these chlorosilanes, and the like Can be illustrated.

In the present invention, when the organopolysiloxane of component (A) is produced by co-hydrolysis and condensation of the above raw material compounds, the resulting organopolysiloxane of component (A) is added to R ¹ SiO _3/2. The unit, R ² ₂ SiO _2/2 unit and / or R ³ _a R ⁴ _b SiO _{(4-ab) / 2} unit may contain a siloxane unit having a silanol group. The organopolysiloxane of component (A) usually contains such silanol group-containing siloxane units in an amount of 0.1 to 10 mol%, preferably about 0.1 to 5 mol%, based on all siloxane units.

Examples of the silanol group-containing siloxane units include (HO) SiO _3/2 units, R ² ′ (HO) SiO _2/2 units, (HO) ₂ SiO _2/2 units, and R ⁴ (HO) SiO _{2 / 2} units, R ⁴ ₂ (HO) SiO _1/2 units, R ³ ′ R ⁴ (HO) SiO _1/2 units, R ⁴ (HO) ₂ SiO _1/2 units (where R ² ′ and R ³ 'Is a group as defined above for R ² and R ³ other than a hydroxyl group, and R ⁴ is as defined above.
Note that the hydroxyl groups in R ^1, R ² and R ^3, means a hydroxyl group in the silanol-containing siloxane units.

  It is preferable that the silanol group-containing siloxane unit is contained within the above range because adhesion to a heat sink, a silicon wafer, a metal, a resin, or the like is improved.

As the structural ratio of the structure of the organopolysiloxane (A), for example, (PhSiO _3/2 ) _x1 (Me ₂ SiO _2/2 ) _m1 (Me ₂ ViSiO _1/2 ) _y1 , (PhSiO _3/2 ) _x1 ( Me ₂ SiO _2/2 ) _m1 (MeViSiO _2/2 ) _y1 , (PhSiO _3/2 ) _x1 (Me ₂ SiO _2/2 ) _m2 (Ph ₂ SiO _2/2 ) _m3 (Me ₂ ViSiO _1/2 ) _y1 , (PhSiO _3/2 ) _x1 (Me ₂ SiO _2/2 ) _m2 (MePhSiO _2/2 ) _m3 (Me ₂ ViSiO _1/2 ) _y1 , (HOSiO _3/2 ) _x1 (Me ₂ SiO _2/2 ) _{m1 (Me 2 ViSiO 1/2) y1,} (PhSiO 3/2) x1 (Me 2 SiO 2/2) m1 (Me (OH) ViSiO 1 _{2) y1, (HOSiO 3/2)} x1 (Me 2 SiO 2/2) m2 (Ph 2 SiO 2/2) m3 (Me 2 ViSiO 1/2) y1, (PhSiO 3/2) x1 (Me 2 SiO _{2/2) m2 (Ph 2 SiO 2/2} ) m3 (Me (HO) ViSiO 1/2) can be exemplified _y1 like.
M1, m2, and m3 are as defined above, and x1 and y1 are positive integers such that x1: m1: y1 or x1: m2 + m3: y1 satisfies 90-24: 75-9: 50-1. X1 + m1 + y1 and x1 + m2 + m3 + y1 are 100.

-(B) Resin-structured organohydrogenpolysiloxane-
The organohydrogenpolysiloxane having a resin structure (that is, a three-dimensional network structure), which is an important component (B) of the addition-curable silicone resin composition used in the heat dissipation sheet of the present invention, is R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units and R ³ _c H _d SiO _{(4-cd) / 2} units (wherein R ¹ , R ² and R ³ are as described above, c is 0, 1 or 2, d is 1 or 2, and c + d is 2 or 3),
A structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions is 10 to 50, preferably 15 to 45, more preferably 20 to 35, is partially Is an organopolysiloxane having a resin structure.

If the number of R ² ₂ SiO _2/2 units is 10 or more, it is preferable because the composition loses its plasticity and becomes difficult to handle, and the cured product when the composition is cured does not become brittle. . Further, if the R ² ₂ SiO _2/2 unit is 50 or less, the composition cannot maintain a solid or semi-solid state, and the cured product does not become too soft. This is preferable because workability does not deteriorate.

The structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions is 10 to 50 means that the component (B) In the molecule of the component (B), at least a part, preferably 50 mol% to 100 mol%, particularly 80 mol% to 100 mol%, of R ² ₂ SiO _2/2 units present in ) Represents a linear diorganopolysiloxane chain structure.

In the molecule of component (B), the R ² ₂ SiO _2/2 unit works to stretch the polymer molecule in a straight line, and the R ¹ SiO _3/2 unit branches the polymer molecule or forms a three-dimensional network. Let The hydrogen atom bonded to silicon in the R ³ _c H _d SiO _{(4-cd) / 2} unit undergoes a hydrosilylation addition reaction with the alkenyl group of the component (A) described above, whereby the composition of the present invention. Plays a role in curing.

(B) The molar ratio of the three essential siloxane units constituting the component, that is, R ¹ SiO _3/2 units: R ² ₂ SiO _2/2 units: R ³ _c H _d SiO _{(4-cd) /} The molar ratio of the _two units is preferably 90 to 24:75 to 9:50 to 1, particularly 70 to 28:70 to 20:10 to 2 (however, 100 in total) from the viewpoint of the properties of the cured product obtained. .

  In addition, the weight average molecular weight in terms of polystyrene by GPC of the component (B) is in the range of 3,000 to 1,000,000, particularly 10,000 to 100,000. From the point of view, it is preferable.

  Such a resin-structured organohydrogenpolysiloxane is a combination of compounds that are raw materials for each unit such that the three siloxane units in the resulting polymer have the required molar ratio, for example, the presence of a catalyst such as an acid. Can be synthesized by co-hydrolysis under.

Here, examples of the raw material of the R ¹ SiO _3/2 unit include MeSiCl ₃ , EtSiCl ₃ , PhSiCl ₃ , n-propyltrichlorosilane, cyclohexyltrichlorosilane, and alkoxysilane such as methoxysilane corresponding to each chlorosilane. it can.

（ここで、ｍ１＝８〜４８の整数（平均値）、ｍ２＝５〜４８の整数（平均値）、ｍ３＝０〜４３の整数（平均値）、ただし、ｍ２＋ｍ３＝８〜４８の整数）
等を例示することができる。 As a raw material of R ² ₂ SiO _2/2 unit,

(Where m1 = integer of 8-48 (average value), m2 = integer of 5-48 (average value), m3 = 0-43 (average value), but m2 + m3 = integer of 8-48
Etc. can be illustrated.

Also, R ³ _c H _d SiO _{(4-cd) / 2} unit is R ³ HSiO _2/2 unit, R ³ ₂ HSiO _1/2 unit, H ₂ SiO _2/2 unit, R ³ H ₂ SiO. It shows that it is an arbitrary combination of one type or two or more types of siloxane units selected from _½ units, and the raw materials thereof include chlorosilanes such as Me ₂ HSiCl, MeHSiCl ₂ , Ph ₂ HSiCl, PhHSiCl _{2, and the} like Examples include alkoxysilanes such as methoxysilanes corresponding to these chlorosilanes.

In the present invention, when the organohydrogenpolysiloxane of component (B) is produced by co-hydrolysis and condensation of the above raw material compounds, the resulting organopolysiloxane of component (B) is added to R ¹ SiO _3. A siloxane unit having a silanol group may be contained in the _{/ 2} unit, R ² ₂ SiO _2/2 unit and / or R ³ _c H _d SiO _{(4-cd) / 2} unit. The (B) component organohydrogenpolysiloxane usually contains such silanol group-containing siloxane units in an amount of 0.1 to 10 mol%, preferably about 0.1 to 5 mol%, based on the total siloxane units. preferable.

Examples of the silanol group-containing siloxane unit include (HO) SiO _3/2 units, R ² ′ (HO) SiO _2/2 units, (HO) ₂ SiO _2/2 units, and H (HO) SiO _{2/2. units,} H 2 _{(HO) SiO 1/2 ^{units, R 3 'H (HO)}} SiO 1/2 _units, H (HO) _{2 SiO 1/2} units (wherein, ^{R 2'} and ^{R 3} 'are other than hydroxyl As defined above for R ² and R ³ ).
Note that the hydroxyl groups in R ^1, R ² and R ^3, means a hydroxyl group in the silanol-containing siloxane units.

  It is preferable that the silanol group-containing siloxane unit is contained within the above range because adhesion to a heat sink, a silicon wafer, a metal, a resin, or the like is improved.

As the structural ratio of the structure of the organopolysiloxane (B), for example, (PhSiO _3/2 ) _x2 (Me ₂ SiO _2/2 ) _m1 (Me ₂ HSiO _1/2 ) _y2 , (PhSiO _3/2 ) _x2 ( Me ₂ SiO _2/2 ) _{m 1} (MeHSiO _2/2 ) _{y 2} , (PhSiO _3/2 ) _{x 2} (Me ₂ SiO _2/2 ) _{m 2} (Ph ₂ SiO _2/2 ) _{m 3} (Me ₂ HSiO _1/2 ) _{y 2} , (PhSiO _3/2 ) _{x 2} (Me ₂ SiO _2/2 ) _{m 2} (MePhSiO _2/2 ) _{m 3} (Me ₂ HSiO _1/2 ) _{y 2} , (HOSiO _3/2 ) _{x 2} (Me ₂ SiO _2/2 ) _{m1 (Me 2 HSiO 1/2) y2,} (PhSiO 3/2) x2 (Me 2 SiO 2/2) m1 (Me (OH) HSiO 1/2) y2 _{(HOSiO 3/2) x2 (Me 2} SiO 2/2) m2 (Ph 2 SiO 2/2) m3 (Me 2 HSiO 1/2) y2, (PhSiO 3/2) x2 (Me 2 SiO 2/2) _{m2 (Ph 2 SiO 2/2) m3} (Me (HO) HSiO 1/2) can be exemplified _y2 like.
M1, m2, and m3 are as defined above, and x2 and y2 are positive integers such that x2: m1: y2 or x2: m2 + m3: y2 satisfies 90-24: 75-9: 50-1. X2 + m1 + y2 and x2 + m2 + m3 + y2 are 100.

  The blending amount of the organohydrogenpolysiloxane of component (B) is the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) relative to the total amount of vinyl groups and allyl groups in component (A). The amount is 0.1 to 4.0, particularly preferably 0.5 to 3.0, and more preferably 0.8 to 2.0. When the curing reaction proceeds well at 0.1 or more and a silicone cured product can be obtained, and 4.0 or less, the amount of unreacted (residual) SiH groups in the cured product becomes small, and the physical properties of the cured product are deteriorated over time. This is preferable because there is no fear of change.

-(C) Platinum group metal catalyst-
This catalyst component is blended in order to accelerate the addition curing reaction of the addition curable silicone resin composition used in the heat-radiating sheet of the present invention, and includes platinum-based, palladium-based, and rhodium-based ones. As the catalyst, any conventionally known catalyst for promoting the hydrosilylation reaction can be used. In consideration of cost and the like, platinum-based materials such as platinum, platinum black, and chloroplatinic acid, such as H ₂ PtCl ₆ · nH ₂ O, K ₂ PtCl ₆ , KHPtCl ₆ · nH ₂ O, K ₂ PtCl ₄ , K ₂ PtCl ₄ · nH ₂ O, PtO ₂ · nH ₂ O, (where n is a positive integer), etc., and complexes thereof with hydrocarbons such as olefins, alcohols, or vinyl group-containing organopolysiloxanes Etc. can be illustrated. These catalysts can be used singly or in combination of two or more.

  The compounding amount of the component (C) may be an effective amount for curing, and is usually 0.1 to 500 ppm in terms of mass as a platinum group metal with respect to the total amount of the component (A) and the component (B). Preferably it is used in the range of 0.5 to 100 ppm.

-(D) Thermally conductive filler-
The thermally conductive filler of component (D) is not particularly limited as long as it does not react with other components in the addition-curable silicone resin composition and stable thermal conductivity and electrical insulation are ensured. For example, metal oxides such as alumina, metal nitrides such as aluminum nitride and boron nitride, powders such as organic resins and silicone rubbers may be used. These may be used alone or in combination of two or more. Can do.

  The range of 100-1500 mass parts is preferable normally with respect to 100 mass parts of all the components (A)-(C), and the range of 400-1000 mass parts is more preferable. If it is such a range, it can be set as the thermal radiation sheet excellent in heat dissipation.

Among these, as the heat conductive filler of the component (D), those having an electrical resistivity of 1 × 10 ¹⁰ Ω · cm or more at 20 ° C. are preferable, and alumina is particularly preferable. If the thermally conductive filler has such an electrical resistivity, the addition-curable silicone resin composition exhibits good electrical insulation, and the resulting heat dissipation sheet and its cured product also have good electrical insulation. Indicates.
In addition, the electrical resistivity in this invention shall show the measured value in 20 degreeC by the method of JISK6249.

-Other ingredients-
In addition to the above-described components (A) to (D), the addition-curable silicone resin composition used in the heat-dissipating sheet of the present invention may contain various publicly known additives as necessary. it can.

・ Inorganic filler:
(D) In addition to the thermally conductive filler, a reinforcing inorganic filler for the purpose of improving the plasticity, shape retention, rubber properties, heat resistance, chemical resistance, light resistance, etc. of the heat radiation sheet Non-reinforcing inorganic fillers can be added. These inorganic fillers are preferably added in an appropriate amount in the range of 0 to 600 parts by mass per 100 parts by mass of the total amount of the components (A) and (B).

・ Adhesion aid:
Moreover, in order to provide adhesiveness to the addition-curable silicone resin composition used for the heat-radiation sheet of this invention, an adhesion | attachment adjuvant can be added as needed. Examples of the adhesion assistant include a hydrogen atom (SiH group) bonded to a silicon atom in one molecule, an alkenyl group (for example, Si—CH═CH ₂ group) bonded to a silicon atom, and an alkoxysilyl group (for example, trimethoxysilyl). Group), an epoxy group (for example, glycidoxypropyl group, 3,4-epoxycyclohexylethyl group), a linear, branched or resin containing at least two, preferably two or three functional groups (Three-dimensional structure) or cyclic organosiloxane oligomer having 4 to 50, preferably about 4 to 20 silicon atoms, organooxysilyl-modified isocyanurate compound represented by the following general formula (2), or hydrolysis thereof Examples include condensates (organosiloxane-modified isocyanurate compounds) and combinations thereof.

〔式中、Ｒ^５は、下記式（３）

（ここで、Ｒ^６は水素原子又は炭素原子数１〜８の一価炭化水素基であり、ｖは１〜６、特に１〜４の整数である。）
で表される有機基、又は脂肪族不飽和結合を含有する一価炭化水素基であるが、Ｒ^５の少なくとも１個は上記式（３）の有機基である。〕

[Wherein R ⁵ represents the following formula (3)

(Here, R ⁶ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms, and v is an integer of 1 to 6, particularly 1 to 4.)
Or a monovalent hydrocarbon group containing an aliphatic unsaturated bond, at least one of R ⁵ is an organic group of the above formula (3). ]

The monovalent hydrocarbon group containing an aliphatic unsaturated bond represented by R ⁵ in the general formula (2) includes a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl group, and a hexenyl group. C2-C8 cycloalkenyl groups, such as C2-C8 alkenyl groups, especially cyclohexenyl groups, and the like. Examples of the monovalent hydrocarbon group for R ⁶ in the above formula (3) include, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, Examples thereof include alkyl groups such as cyclohexyl groups, alkenyl groups and cycloalkenyl groups exemplified for R ⁵ above, and monovalent hydrocarbon groups having 1 to 8 carbon atoms, particularly 1 to 6 carbon atoms such as aryl groups such as phenyl groups, An alkyl group is preferred.

（式中、ｇ及びｈは各々０〜５０の範囲の正の整数であって、しかもｇ＋ｈが２〜５０、好ましくは４〜２０を満足するものである。） Furthermore, examples of the adhesion assistant include compounds represented by the following formula.

(In the formula, g and h are each a positive integer in the range of 0 to 50, and g + h satisfies 2 to 50, preferably 4 to 20.)

  Among the above-mentioned organosilicon compounds, compounds that provide particularly good adhesion to the resulting cured product have a silicon atom-bonded alkoxy group and an alkenyl group or silicon atom-bonded hydrogen atom (SiH group) in one molecule. It is an organosilicon compound.

  The compounding amount of the adhesion assistant is usually 0 to 10 parts by mass, preferably 0.1 to 8 parts by mass, more preferably about 0.2 to 5 parts by mass with respect to 100 parts by mass of the component (A). Can do. If it is 10 parts by mass or less, the hardness of the cured product will not be adversely affected, and the surface will not be sticky.

  Furthermore, a liquid silicone component can be added to the addition-curable silicone resin composition used for the heat dissipation sheet of the present invention, if necessary. As such a liquid silicone component, those having a viscosity at 25 ° C. of 1 to 100,000 mPa · s measured with a Brookfield rotational viscometer by a method according to JIS K 7117-1 are preferable. Gensiloxane, alkoxysiloxane, hydroxysiloxane, and mixtures thereof can be mentioned, and the addition amount is a condition that the addition-curable silicone resin composition maintains a solid or semi-solid at room temperature, and is usually an addition-curable silicone resin. It is 50 mass% or less with respect to the whole composition.

・ Curing inhibitor:
The addition curable silicone resin composition used in the heat-dissipating sheet of the present invention can be appropriately blended with a curing inhibitor as needed for the purpose of adjusting the curing rate. Examples of the curing inhibitor include high vinyl group-containing organopolysiloxanes such as tetramethyltetravinylcyclotetrasiloxane and hexavinyldisiloxane, triallyl isocyanurate, alkyl maleates, acetylene alcohols and their silane-modified products and siloxanes. Examples thereof include compounds selected from the group consisting of modified products, hydroperoxides, tetramethylethylenediamine, benzotriazole, and mixtures thereof. The curing inhibitor is usually added in an amount of 0.001 to 1.0 part by mass, preferably 0.005 to 0.5 part by mass, per 100 parts by mass of the component (A).

·Silane coupling agent:
The above (D) thermally conductive filler can be treated with a silane coupling agent in order to improve dispersibility in the resin. As a silane coupling agent, a compound represented by the following general formula (A),
R ⁷ Si (OR ⁸ ) ₃ (A)
(Here, R ⁷ is an aliphatic alkyl group, and R ⁸ is a methyl group or an ethyl group.)
It _{consists of} R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where R ¹ , R ² , and R ³ Independently represents a hydroxyl group, a methyl group, an ethyl group, a propyl group, a cyclohexyl group, or a phenyl group, R ⁴ independently represents a vinyl group or an allyl group, a is 0, 1 or 2, and b is 1 or 2 And a + b is 2 or 3.)
A polysiloxane comprising a structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated, the number of repetitions of which is 5 to 50, and the terminal is blocked with ₃ units of Si (OR ⁸ ) (Here, R ⁸ is the same as above.)
Is mentioned.

  As a typical example of the addition-curable silicone resin composition used for the heat dissipation sheet of the present invention, a composition substantially composed of the components (A) to (D) can be given. Here, “consisting essentially of the components (A) to (D)” means that the composition comprises at least one of the above-mentioned optional components other than the components (A) to (D) according to the purpose, etc. It means that it can be included as needed.

-Preparation-
The heat-dissipating sheet of the present invention is formed by disposing the addition-curable silicone resin composition as described above on both surfaces of the metal layer serving as a core material. Usually, the silicone resin composition is stored at a low temperature in a refrigerator or a freezer so that the curing does not proceed, and is immediately cured by heating when necessary.

  The metal layer that is the core material of the heat-dissipating sheet of the present invention desirably has high thermal conductivity for the purpose of use, but the thickness and shape are not particularly limited, and can be selected according to the application. .

  As a metal layer, if it consists of a metal chosen from aluminum, copper, silver, and those alloys, since it has high heat conductivity, it is preferable.

  On the other hand, the addition-curable silicone resin composition preferably has a thickness of 100 μm or less. The smaller the thickness, the greater the contribution of the core metal layer and the better the thermal conductivity. However, in addition to the decrease in electrical insulation, the type and content of the component (D) are limited. Therefore, it is adjusted as appropriate according to the application.

Examples of means for producing the heat dissipation sheet of the present invention include a film coater and a heat press. In order to produce a heat dissipation sheet using these means, for example, a metal is sandwiched between the above-mentioned addition-curable silicone resin composition, and a base film for pressure is placed on one side and a release film is placed on the other side, Usually 60 to 120 ° C. using a hot press, preferably at a temperature of 70~100 ℃, 0.5~10t / cm ^2, preferably under a pressure of 1~7t / cm ^2, 1~30 minutes, preferably Perform compression molding for 2 to 10 minutes.

  Examples of the base film for pressurization and the release film include a fluorine resin-coated PET film, a silicone resin-coated PET film, a fluorine resin film, and the like. It may be used.

  The heat-dissipating sheet produced as described above is solid or semi-solid at normal temperature, and its surface is non-adhesive, so it is easy to handle. In addition, since the adhesion between the metal layer as the core and the addition-curable silicone resin composition is good, excellent thermal conductivity can be obtained. Further, the addition-curable silicone resin composition is cured by further heating and exhibits adhesiveness.

  As a method of using such a heat dissipation sheet, it is arranged in an arbitrary shape and size on the surface of a heat generating component (electronic component), and is heated and brought into close contact. After that, by adding a heat sink and performing secondary curing, the addition-curable silicone resin composition is cured, and the gap between the heat-generating component and the heat sink can be filled without any gap.

  Curing of the heat dissipation sheet of the present invention is usually performed at a temperature of 50 to 200 ° C., particularly 70 to 180 ° C., and the heating time may be 1 to 30 minutes, particularly about 2 to 10 minutes. Further, secondary curing (post-cure) can be performed, and the temperature for this is usually 50 to 200 ° C., particularly 70 to 180 ° C., and the time may be 0.1 to 10 hours, particularly 1 to 4 hours. Usually, secondary curing is performed after primary curing.

  The sheet-like cured product obtained by heating and curing the heat-dissipating sheet as described above becomes a highly heat-dissipating sheet-like cured product having excellent self-adhesiveness, electrical insulation, and heat dissipation.

  Further, the sheet-like cured product has high thermal conductivity as described above, and the thermal conductivity is 1.5 W / m · K or more as measured by the method described in JIS H7801. It is particularly preferably 1.8 W / m · K or more.

  In addition, it is preferable that the highly heat-dissipating sheet-like cured product has a type D durometer hardness of 30 or more described in JIS K 6253 because it becomes a highly heat-dissipating sheet-like cured product having sufficient strength.

  Moreover, if the surface of this highly heat-radiative sheet-like cured product is non-tacky, it is preferable because it is easy to handle after curing.

  As described above, the heat-dissipating sheet of the present invention is a metal having a high thermal conductivity and a heat-conductive addition-curable silicone resin composition having no adhesiveness and having excellent self-adhesiveness and electrical insulation. By arranging on both sides of the layer, the surface is not sticky and easy to handle, and because it has good self-adhesiveness, the contact thermal resistance with the metal layer that is the core material is suppressed, and the heating element and heat sink Since a metal layer having a high thermal conductivity can be used as a core material, the space sheet can be filled without any gaps, and the heat dissipation sheet is excellent in heat dissipation and also in electrical insulation. For this reason, the heat-radiation sheet of this invention is suitable as a heat conductive material for efficiently transmitting the heat generated in the electronic component to the heat sink.

  EXAMPLES Hereinafter, although a synthesis example, a preparation example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. Ph represents a phenyl group, Me represents a methyl group, and Vi represents a vinyl group.

[Synthesis Example 1]
-Vinyl group-containing organopolysiloxane resin (A1)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₂₃ SiMe ₂ Cl: 1 mol, Me ₂ ViSiCl: 6 mol was dissolved in a toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a vinyl group-containing resin (A1).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₂₃ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 23 -SiMe 2 O 2/2] 0.01 [Me 2 ViSiO 1/2] 0.06. This resin had a weight average molecular weight of 65,000 and a melting point of 58 ° C.

[Synthesis Example 2]
-Hydrosilyl group-containing organopolysiloxane resin (B1)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₂₃ SiMe ₂ Cl: 1 mol, Me ₂ HSiCl: 6 mol were dissolved in toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B1).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₂₃ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 23 -SiMe 2 O 2/2] 0.01 [Me 2 HSiO 1/2] 0.06. This resin had a weight average molecular weight of 56,000 and a melting point of 56 ° C.

[Synthesis Example 3]
-Vinyl group-containing organopolysiloxane resin (A2)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₂₃ SiMe ₂ Cl: 1 mol, MeViSiCl ₂ : 3 mol was dissolved in toluene solvent, dropped into water, co-hydrolyzed, further washed with water, alkali After neutralization and dehydration by washing, the solvent was stripped to synthesize a vinyl group-containing resin (A2).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₂₃ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ -SiMe ₂ O- (Me ₂ SiO) ₂₃ -SiMe ₂ O _2/2 ] _0.01 [MeViSiO _2/2 ] _0.03 . This resin had a weight average molecular weight of 62,000 and a melting point of 60 ° C.

[Synthesis Example 4]
-Hydrosilyl group-containing organopolysiloxane resin (B2)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₂₃ SiMe ₂ Cl: 1 mol, MeHSiCl ₂ : 3 mol was dissolved in toluene solvent, dropped into water, co-hydrolyzed, further washed with water, alkali After neutralization and dehydration by washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B2).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₂₃ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ -SiMe ₂ O- (Me ₂ SiO) ₂₃ -SiMe ₂ O _2/2 ] _0.01 [MeHSiO _2/2 ] _0.03 . This resin had a weight average molecular weight of 58,000 and a melting point of 58 ° C.

[Synthesis Example 5]
-Vinyl group-containing organopolysiloxane resin (A3)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₃₃ SiMe ₂ Cl: 1 mol, Me ₂ ViSiCl: 3 mol dissolved in a toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a vinyl group-containing resin (A3).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₃₃ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 33 -SiMe 2 O 2/2] 0.01 [Me 2 ViSiO 1/2] 0.03. This resin had a weight average molecular weight of 63,000 and a melting point of 63 ° C.

[Synthesis Example 6]
-Hydrosilyl group-containing organopolysiloxane resin (B3)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₃₃ SiMe ₂ Cl: 1 mol, Me ₂ HSiCl: 3 mol dissolved in toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B3).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₃₃ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 33 -SiMe 2 O 2/2] 0.01 [Me 2 HSiO 1/2] 0.03. This resin had a weight average molecular weight of 57,000 and a melting point of 56 ° C.

[Synthesis Example 7]
-Vinyl group-containing organopolysiloxane resin (A4)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₈ SiMe ₂ Cl: 1 mol, Me ₂ ViSiCl: 6 mol was dissolved in a toluene solvent, dropped into water, cohydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a vinyl group-containing resin (A4).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₈ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 8 -SiMe 2 O 2/2] 0.01 [Me 2 ViSiO 1/2] 0.06. This resin had a weight average molecular weight of 45,000 and a melting point of 56 ° C.

[Synthesis Example 8]
-Hydrosilyl group-containing organopolysiloxane resin (B4)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₈ SiMe ₂ Cl: 1 mol, Me ₂ HSiCl: 6 mol dissolved in toluene solvent, dropped into water, cohydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B4).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₈ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 8 -SiMe 2 O 2/2] 0.01 [Me 2 HSiO 1/2] 0.06. This resin had a weight average molecular weight of 42,000 and a melting point of 60 ° C.

[Synthesis Example 9]
-Vinyl group-containing organopolysiloxane resin (A5)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₄₈ SiMe ₂ Cl: 1 mol, Me ₂ ViSiCl: 6 mol was dissolved in a toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a vinyl group-containing resin (A5).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₄₈ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 48 -SiMe 2 O 2/2] 0.01 [Me 2 ViSiO 1/2] 0.06. This resin had a weight average molecular weight of 60,000 and a melting point of 62 ° C.

[Synthesis Example 10]
-Hydrosilyl group-containing organopolysiloxane resin (B5)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₄₈ SiMe ₂ Cl: 1 mol, Me ₂ HSiCl: 6 mol were dissolved in toluene solvent, then dropped in water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B5).
This resin has a constitutional ratio of a siloxane unit constituting and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₄₈ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 48 -SiMe 2 O 2/2] 0.01 [Me 2 HSiO 1/2] 0.06. This resin had a weight average molecular weight of 58,000 and a melting point of 54 ° C.

[Comparative Synthesis Example 1]
-Vinyl group-containing organopolysiloxane resin (A6)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₇ SiMe ₂ Cl: 1 mol, Me ₂ ViSiCl: 6 mol was dissolved in a toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a vinyl group-containing resin (A6).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₇ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 7 -SiMe 2 O 2/2] 0.01 [Me 2 ViSiO 1/2] 0.06. This resin had a weight average molecular weight of 45,000 and a melting point of 56 ° C.

[Comparative Synthesis Example 2]
-Hydrosilyl group-containing organopolysiloxane resin (B6)-
Organosilane represented by PhSiCl ₃ : 27 mol, ClMe ₂ SiO (Me ₂ SiO) ₇ SiMe ₂ Cl: 1 mol, Me ₂ HSiCl: 6 mol dissolved in toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B6).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₇ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 7 -SiMe 2 O 2/2] 0.01 [Me 2 HSiO 1/2] 0.06. This resin had a weight average molecular weight of 42,000 and a melting point of 54 ° C.

[Comparative Synthesis Example 3]
-Vinyl group-containing organopolysiloxane resin (A7)-
Organosilane represented by PhSiCl ₃ : 27 mol, HOMe ₂ SiO (Me ₂ SiO) ₉₈ SiMe ₂ OH: 1 mol, Me ₂ ViSiCl: 6 mol was dissolved in a toluene solvent, dropped into water, cohydrolyzed, further washed with water, After neutralization by alkali washing and dehydration, the solvent was stripped to synthesize a vinyl group-containing resin (A7).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₉₈ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 98 -SiMe 2 O 2/2] 0.01 [Me 2 ViSiO 1/2] 0.06. This resin was in the form of a paste having a weight average molecular weight of 64,000.

[Comparative Synthesis Example 4]
-Hydrosilyl group-containing organopolysiloxane resin (B7)-
Organosilane represented by PhSiCl ₃ : 27 mol, HOMe ₂ SiO (Me ₂ SiO) ₉₈ SiMe ₂ OH: 1 mol, Me ₂ HSiCl: 6 mol are dissolved in a toluene solvent, then dropped in water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B7).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₉₈ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 98 -SiMe 2 O 2/2] 0.01 [Me 2 HSiO 1/2] 0.06. This resin was in the form of a paste having a weight average molecular weight of 62,000.

[Comparative Synthesis Example 5]
-Vinyl group-containing organopolysiloxane resin (A8)-
Organosilane represented by PhSiCl ₃ : 27 mol, HOMe ₂ SiO (Me ₂ SiO) ₄₉ SiMe ₂ OH: 1 mol, Me ₂ ViSiCl: 6 mol was dissolved in a toluene solvent, dropped into water, cohydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a vinyl group-containing resin (A8).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₄₉ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 49 -SiMe 2 O 2/2] 0.01 [Me 2 ViSiO 1/2] 0.06. This resin was in the form of a paste having a weight average molecular weight of 64,000.

[Comparative Synthesis Example 6]
-Hydrosilyl group-containing organopolysiloxane resin (B8)-
Organosilane represented by PhSiCl ₃ : 27 mol, HOMe ₂ SiO (Me ₂ SiO) ₄₉ SiMe ₂ OH: 1 mol, Me ₂ HSiCl: 6 mol, dissolved in toluene solvent, dropped into water, co-hydrolyzed, further washed with water, After neutralization and dehydration by alkali washing, the solvent was stripped to synthesize a hydrosilyl group-containing resin (B8).
This resin has a constitutional ratio of a siloxane unit and a structure represented by [—SiMe ₂ O— (Me ₂ SiO) ₄₉ —SiMe ₂ O _2/2 ] represented by the formula: [PhSiO _3/2 ] _0.27 [ represented by _{-SiMe 2 O- (Me 2 SiO)} 49 -SiMe 2 O 2/2] 0.01 [Me 2 HSiO 1/2] 0.06. This resin was in the form of a paste having a weight average molecular weight of 62,000.

[Preparation Example 1]
Vinyl group-containing resin (A1) obtained in Synthesis Example 1: 50 g, hydrosilyl group-containing resin (B1) obtained in Synthesis Example 2: 50 g, acetylene alcohol-based ethynylcyclohexanol as a reaction inhibitor: 0.2 g, Octyl alcohol modified solution of chloroplatinic acid: 0.1 g was added to prepare a base composition. After adding 500 parts by mass of alumina powder (AC-9200; manufactured by Admatex) to 100 parts by mass of this base composition, the mixture was thoroughly stirred with a planetary mixer to prepare alumina-containing silicone resin composition 1. Composition 1 was a plastic solid at 25 ° C.

[Example 1]
The composition 1 thus obtained was sandwiched between a PET film (pressurizing base film) and a fluororesin-coated PET film (peeling film), and was heated at 80 ° C. under a pressure of 5 t / cm ² . Then, compression molding was performed for 5 minutes to form a sheet having a thickness of 50 μm.
The release film is peeled off from this sheet-shaped resin composition, the resin surfaces are attached to both sides of a 75 μm thick copper foil, and compression molding is performed at 80 ° C. under a pressure of 5 t / cm ² for 5 minutes using a hot press machine. The heat radiating sheet 1 was obtained.

Next, the heat-radiation sheet 1 produced in this way was evaluated by the following evaluation items 1) to 4).
1) Evaluation of surface adhesiveness The base film was peeled off from the heat-dissipating sheet 1, and the adhesiveness of the surface was confirmed by finger touch.
2) Dielectric breakdown voltage measurement The heat dissipation sheet 1 was cured at 150 ° C. for 4 hours, the base film was peeled off, and the dielectric breakdown voltage was measured according to the method described in JIS K 6249.
3) Thermal conductivity measurement Thermal conductivity was measured using a laser flash method (LFA 447 Nanoflash, Netchgerei Debau). The heat-dissipating sheet 1 is sandwiched between two aluminum plates with a diameter of 1 cm and a thickness of 1 mm, heated at 150 ° C. for 4 hours to form a cured product, and the whole is coated with carbon black so that the measurement laser beam is not reflected. did. The thermal conductivity was measured using this as a test piece.
4) Adhesive The base film is peeled off from the heat-dissipating sheet 1 and bonded to a copper foil having a thickness of 35 μm and a width of 1 cm, and then compressed using a hot press machine at 100 ° C. under a pressure of 5 t / cm ² for 5 minutes. Adhered and heat cured at 150 ° C. for 4 hours. The bonded copper foil was subjected to a 90 ° peel test by the method described in JIS K 6854-1, and the adhesive strength was measured. (Autograph AG-IS manufactured by Shimadzu Corporation)
Table 1 shows the measurement results of the evaluation items 1) to 4).

[Preparation Example 2]
Vinyl group-containing resin (A-2) obtained in Synthesis Example 3 instead of vinyl group-containing resin (A-1): 50 g, obtained in Synthesis Example 4 instead of hydrosilyl group-containing resin (B-1) Hydrosilyl group-containing resin (B-2): Alumina-containing silicone resin composition 2 was prepared in the same manner as in Preparation Example 1, except that 50 g was used. Composition 2 was a plastic solid at 25 ° C.

[Example 2]
Using the composition 2 obtained in Preparation Example 2 instead of the composition 1, the same operation as in Example 1 was performed to prepare a heat dissipation sheet 2.
This heat radiating sheet 2 was evaluated in the same manner as in Example 1 by the above-described evaluation items 1) to 4). The results are shown in Table 1.

[Preparation Example 3]
Vinyl group-containing resin (A-3) obtained in Synthesis Example 5 instead of vinyl group-containing resin (A-1): 50 g, obtained in Synthesis Example 6 instead of hydrosilyl group-containing resin (B-1) Hydrosilyl group-containing resin (B-3): Alumina-containing silicone resin composition 3 was prepared in the same manner as in Preparation Example 1, except that 50 g was used. Composition 3 was a plastic solid at 25 ° C.

[Example 3]
Using the composition 3 obtained in Preparation Example 3 instead of the composition 1, the same operation as in Example 1 was performed to produce a heat dissipation sheet 3.
This heat radiating sheet 3 was evaluated in the same manner as in Example 1 by the above evaluation items 1) to 4). The results are shown in Table 1.

[Preparation Example 4]
Vinyl group-containing resin (A-4) obtained in Synthesis Example 7 instead of vinyl group-containing resin (A-1): 50 g, obtained in Synthesis Example 8 instead of hydrosilyl group-containing resin (B-1) Hydrosilyl group-containing resin (B-4): Alumina-containing silicone resin composition 4 was prepared in the same manner as in Preparation Example 1, except that 50 g was used. Composition 4 was a plastic solid at 25 ° C.

[Example 4]
Using the composition 4 obtained in Preparation Example 4 instead of the composition 1, the same operation as in Example 1 was performed to produce a heat dissipation sheet 4.
This heat radiating sheet 4 was evaluated in the same manner as in Example 1 by the evaluation items 1) to 4). The results are shown in Table 1.

[Preparation Example 5]
Vinyl group-containing resin (A-5) obtained in Synthesis Example 9 instead of vinyl group-containing resin (A-1): 50 g, obtained in Synthesis Example 10 instead of hydrosilyl group-containing resin (B-1) Hydrosilyl group-containing resin (B-5): Alumina-containing silicone resin composition 5 was prepared in the same manner as in Preparation Example 1, except that 50 g was used. Composition 5 was a plastic solid at 25 ° C.

[Example 5]
Using the composition 5 obtained in Preparation Example 5 instead of the composition 1, the same operation as in Example 1 was performed to produce a heat dissipation sheet 5.
This heat radiating sheet 5 was evaluated in the same manner as in Example 1 according to the above evaluation items 1) to 4). The results are shown in Table 1.

[Preparation Example 6]
Vinyl group-containing resin (A-6) obtained in Comparative Synthesis Example 1 instead of vinyl group-containing resin (A-1): 50 g, obtained in Comparative Synthesis Example 2 instead of hydrosilyl group-containing resin (B-1) Obtained hydrosilyl group-containing resin (B-6): Alumina-containing silicone resin composition 6 was prepared in the same manner as in Preparation Example 1, except that 50 g was used. The composition 6 was a solid having no plasticity at 25 ° C.

[Comparative Example 1]
The composition 6 obtained in Preparation Example 6 was evaluated in the same manner as in Example 1. However, the cured product was very fragile and could not be evaluated because the shape could not be maintained.

[Preparation Example 7]
Vinyl group-containing resin (A-7) obtained in Comparative Synthesis Example 3 instead of vinyl group-containing resin (A-1): 50 g, obtained in Comparative Synthesis Example 4 instead of hydrosilyl group-containing resin (B-1) The resulting hydrosilyl group-containing resin (B-7): Alumina-containing silicone resin composition 7 was prepared in the same manner as in Preparation Example 1, except that 50 g was used. The composition 7 was pasty at 25 ° C. and could not retain its shape.

[Comparative Example 2]
Using the composition 7 obtained in Preparation Example 7 instead of the Composition 1, the same operation as in Example 1 was performed to produce a heat dissipation sheet 7.
This heat radiating sheet 7 was evaluated in the same manner as in Example 1 by the above evaluation items 1) to 4). The results are shown in Table 1.

[Preparation Example 8]
Vinyl group-containing resin (A-8) obtained in Comparative Synthesis Example 5 instead of vinyl group-containing resin (A-1): 50 g, obtained in Comparative Synthesis Example 6 instead of hydrosilyl group-containing resin (B-1) Obtained hydrosilyl group-containing resin (B-8): Alumina-containing silicone resin composition 8 was prepared in the same manner as in Preparation Example 1, except that 50 g was used. This composition 8 was pasty at 25 ° C. and could not retain its shape.

[Comparative Example 3]
Using the composition 8 obtained in Preparation Example 8 instead of the Composition 1, the same operation as in Example 1 was performed to produce a heat dissipation sheet 8.
The heat radiating sheet 8 was evaluated in the same manner as in Example 1 by the evaluation items 1) to 4). The results are shown in Table 1.

[Preparation Example 9]
In Preparation Example 1, instead of 100 parts by mass of the base composition, KJR-632 (manufactured by Shin-Etsu Chemical Co., Ltd.), which is a commercially available addition-curable silicone varnish mainly composed of a vinyl group-containing organopolysiloxane resin that is liquid at room temperature ) Alumina-containing silicone resin composition 9 was prepared in the same manner as Preparation Example 1 except that 100 parts by mass was used. This composition 9 was liquid at 25 ° C. and could not retain its shape.

[Comparative Example 4]
Using the composition 9 obtained in Preparation Example 9 instead of the Composition 1, the same operation as in Example 1 was performed to prepare a heat dissipation sheet 9.
The heat radiating sheet 9 was evaluated in the same manner as in Example 1 by the above-described evaluation items 1) to 4). The results are shown in Table 1.

[Preparation Example 10]
In Preparation Example 1, instead of 100 parts by mass of the base composition, KJR-632L-1 (Shin-Etsu Chemical Co., Ltd.), which is a commercially available addition-curable silicone varnish mainly composed of a vinyl group-containing organopolysiloxane resin that is liquid at room temperature. A) An alumina-containing silicone resin composition 10 was prepared in the same manner as in Preparation Example 1 except that 100 parts by mass were used. This composition 10 was liquid at 25 ° C. and could not retain its shape.

[Comparative Example 5]
Using the composition 10 obtained in Preparation Example 10 instead of the composition 1, the same operation as in Example 1 was performed to produce a heat-dissipating sheet 10.
This heat-dissipating sheet 10 was evaluated according to the evaluation items 1) to 4) in the same manner as in Example 1. The results are shown in Table 1.

As shown in Table 1, Examples 1 to 5 using compositions 1 to 5 in which the number of repeating R ² SiO _2/2 units of the addition-curable silicone resin composition is in the range of 10 to 50 are as follows: Since it was solid at normal temperature and was not sticky, it was easy to handle. Moreover, what was hardened | cured had the outstanding electrical insulation, heat conductivity, and adhesive strength.
On the other hand, in Comparative Example 1 using the composition 6 in which the number of repeating R ² SiO _2/2 units of the addition-curable silicone resin composition is 9, the cured product is very brittle and maintains its shape. Could not be evaluated. Further, Comparative Example 2 and Comparative Example 3 using the composition 7 and the composition 8 in which the number of repeating R ² SiO _2/2 units of the addition-curable silicone resin composition exceeds 50 are paste-like at normal temperature. Moreover, Comparative Example 4 and Comparative Example 5 using a commercially available addition-curable silicone varnish mainly composed of a vinyl group-containing organopolysiloxane resin that is liquid at room temperature were liquid at room temperature. In these comparative examples 2 to 5, the adhesiveness is strong when the heat-dissipating sheet is produced, and if the base film is peeled off before post-cure, the resin part is peeled off from the metal of the core material, resulting in thermal conductivity and adhesiveness. Could not be measured.

[Example 6]
Using the composition 1 obtained in Preparation Example 1, the same operation as in Example 1 was performed using an aluminum foil having a thickness of 75 μm instead of the copper foil having a thickness of 75 μm as a core material, so that a heat radiation sheet 11 was produced.
This heat radiating sheet 11 was evaluated according to the evaluation items 1) to 3) in the same manner as in Example 1. The results are shown in Table 2.

[Example 7]
An operation similar to that of Example 6 was performed using a silver foil having a thickness of 75 μm as a core material instead of the aluminum foil having a thickness of 75 μm, so that the heat radiation sheet 12 was produced.
This heat radiating sheet 12 was evaluated according to the above evaluation items 1) to 3) in the same manner as in Example 1. The results are shown in Table 2.

[Example 8]
The same operation as in Example 6 was performed using an aluminum plate having a thickness of 1 mm instead of the aluminum foil having a thickness of 75 μm as a core material, so that a heat radiation sheet 13 was produced. This heat radiating sheet 13 was evaluated according to the above evaluation items 1) to 3) in the same manner as in Example 1. The evaluation was performed by the same method as described above, but the thermal conductivity was measured by spraying carbon black on the heat-cured heat-dissipating sheet without being sandwiched between two aluminum plates and directly measuring the thermal conductivity. . The results are shown in Table 2.

[Comparative Example 6]
The same operation as in Example 6 was performed using KJR-632L-1 (manufactured by Shin-Etsu Chemical Co., Ltd.), which is a silicone resin having a thickness of 75 μm, instead of the aluminum foil having a thickness of 75 μm, and the heat radiation sheet 14 was produced. did.
This heat radiating sheet 14 was evaluated in the same manner as in Example 1 by the evaluation items 1) to 3). The results are shown in Table 2.

[Comparative Example 7]
The same operation as in Example 6 was performed by using KJR-632L-1 (manufactured by Shin-Etsu Chemical Co., Ltd.), which is a silicone resin having a thickness of 1 mm, instead of the aluminum foil having a thickness of 75 μm, and the heat radiation sheet 15 was produced. did.
The heat radiating sheet 15 was evaluated in the same manner as in Example 8 according to the evaluation items 1) to 3). The results are shown in Table 2.

  As shown in Table 2, the dielectric breakdown voltage varied depending only on the thickness of the silicone resin, and the thermal conductivity depended only on the thickness regardless of the type when the core material was a metal. . This is probably because the thermal conductivity of the metal is much larger than that of the silicone resin composition. From this, when preparing the heat-radiating sheet of the present invention, by adjusting the thickness of the addition-curable silicone resin composition and the metal layer serving as the core material, the heat-radiating sheet having desired electrical insulation and heat dissipation It was suggested that can be made.

  As described above, the heat-dissipating sheet of the present invention is easy to handle because there is no stickiness on the surface, and since it has good self-adhesiveness, the contact thermal resistance with the metal layer as the core material is suppressed, and high heat conduction is achieved. It has been clarified that since the metal layer having a rate is used as a core material, it has excellent heat dissipation and electrical insulation.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Claims (10)

  A heat radiating sheet in which a solid or semi-solid addition-curable silicone resin composition containing a thermally conductive filler is coated on both surfaces of a metal layer, and the surface of the heat radiating sheet is non-adhesive A heat dissipation sheet characterized by being a thing. The addition-curable silicone resin composition is
(A) R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where R ¹ , R ² , And R ³ independently represents any of a hydroxyl group, a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and a phenyl group, R ⁴ independently represents a vinyl group or an allyl group, and a is 0, 1 or 2 , B is 1 or 2, and a + b is 2 or 3.)
An organopolysiloxane having a resin structure including a structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions thereof is 10 to 50;
(B) R ¹ SiO _3/2 units, R ² ₂ SiO _2/2 units, and R ³ _c H _d SiO _{(4-cd) / 2} units (where R ¹ , R ² and R ³ is independently as described above, c is 0, 1 or 2, d is 1 or 2, and c + d is 2 or 3.
Resin-structured organohydrogenpolysiloxane comprising a structure in which at least a part of the R ² ₂ SiO _2/2 unit is continuously repeated and the number of repetitions thereof is 10 to 50: in the component (A) The amount of hydrogen atoms bonded to silicon atoms in component (B) relative to the total of vinyl groups and allyl groups is 0.1 to 4.0 by molar ratio,
2. The catalyst according to claim 1, comprising (C) a platinum group metal-based catalyst: an effective amount of curing, and (D) a thermally conductive filler, which is solid or semisolid at room temperature when uncured. Heat dissipation sheet.   The addition-curable silicone resin composition contains 100 to 1,500 parts by mass of the (D) thermally conductive filler with respect to a total of 100 parts by mass of the components (A) to (C). The heat dissipating sheet according to claim 2. 4. The heat dissipation sheet according to claim 2, wherein the (D) heat conductive filler has an electrical resistivity at 20 ° C. of 1 × 10 ¹⁰ Ω · cm or more.   The heat dissipation sheet according to any one of claims 1 to 4, wherein the metal layer is made of a metal selected from aluminum, copper, silver, and alloys thereof.   A highly heat-dissipating sheet-like cured product, which is a heat-cured product of the heat-dissipating sheet according to any one of claims 1 to 5.   The highly heat-dissipating sheet-like cured product according to claim 6, wherein the type D durometer hardness according to JIS K 6253 is 30 or more.   The highly heat-dissipating sheet-like cured product according to claim 6 or 7, wherein a surface of the highly heat-dissipating sheet-like cured product is non-adhesive.   The high heat dissipation sheet-like cured product has a thermal conductivity of 1.5 W / m · K or more, and the high heat dissipation property according to any one of claims 6 to 8. Sheet-like cured product.   A method of using a heat dissipation sheet, wherein the heat dissipation sheet according to any one of claims 1 to 5 is used after being heat-cured after being brought into close contact with an electronic component.