CN112714784B - Heat-conductive silicone composition and cured product thereof - Google Patents
Heat-conductive silicone composition and cured product thereof Download PDFInfo
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—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
- C08L83/04—Polysiloxanes
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- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/12—Polysiloxanes containing silicon bound to hydrogen
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- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
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- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
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- C08K5/00—Use of organic ingredients
- C08K5/54—Silicon-containing compounds
- C08K5/541—Silicon-containing compounds containing oxygen
- C08K5/5415—Silicon-containing compounds containing oxygen containing at least one Si—O bond
- C08K5/5419—Silicon-containing compounds containing oxygen containing at least one Si—O bond containing at least one Si—C bond
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—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
- C08L83/04—Polysiloxanes
- C08L83/06—Polysiloxanes containing silicon bound to oxygen-containing groups
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
- C08K2003/265—Calcium, strontium or barium carbonate
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- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
- C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
Abstract
The present invention relates to a thermally conductive silicone composition, characterized by comprising: 100 parts by mass of (a) an organopolysiloxane having at least 2 alkenyl groups in one molecule; (B) An organohydrogenpolysiloxane having at least 2 Si-H groups in an amount such that the number of Si-H groups is 0.1 to 5.0 times the number of alkenyl groups derived from the component (a); 700 to 2,500 parts by mass of (C) a thermally conductive filler; (D) A platinum group metal-based curing catalyst comprising, based on the mass of the metal element in terms of component (A), from 0.1 to 2,000ppm, wherein component (C) comprises from 400 to 2,000 parts by mass of a (C-1) ground calcium carbonate filler having an average particle diameter of from 12 to 50 μm and from 0.1 to 1,500 parts by mass of a (C-2) ground calcium carbonate filler having an average particle diameter of from 0.4 to 10 μm. Thus, a thermally conductive silicone composition capable of providing a thermally conductive resin molded body having excellent compressibility, insulation properties, thermal conductivity, and processability, and a cured product thereof are provided.
Description
Technical Field
The present invention relates to a thermally conductive silicone composition and a cured product thereof.
Background
Large scale integrated circuit (LSI chip) chips such as CPU, driver IC, and memory used in electronic devices such as personal computers, digital video disks, and mobile phones generate a large amount of heat in their own right with high performance, high speed, small size, and high integration, and the increase in temperature of the chips due to the heat causes malfunction and damage of the chips. Therefore, many heat dissipation methods, and heat dissipation members used for these methods have been proposed to suppress the temperature rise of the chip in operation.
Conventionally, in electronic devices and the like, a heat sink (heat sink) using a metal plate having high thermal conductivity such as aluminum or copper has been used in order to suppress a temperature rise of a chip during operation. The heat sink can conduct heat generated by the chip and release the heat from the surface through a temperature difference with the outside air.
In order to efficiently transfer heat generated by the chip to the heat sink, the heat sink needs to be in close contact with the chip, but since there is a difference in height between the chips or a tolerance due to assembly processing, a flexible sheet or paste is interposed between the chip and the heat sink, and heat transfer from the chip to the heat sink is achieved via the sheet or paste.
A thermally conductive sheet (thermally conductive silicone rubber sheet) made of thermally conductive silicone rubber or the like is used in various fields because the sheet is superior in handling properties compared to paste.
Patent document 1 discloses an insulating composition in which 100 to 800 parts by mass of at least 1 or more metal oxides selected from beryllium oxide, aluminum hydroxide, magnesium oxide, and zinc oxide are blended with 100 parts by mass of synthetic rubber such as silicone rubber.
On the other hand, electronic devices such as personal computers, word processors, and CD-ROM drives (CD-ROM drives) have been increasingly highly integrated, and the amount of heat generated by integrated circuit elements such as LSIs and CPUs in the devices has increased, so that conventional cooling methods have been insufficient. In particular, in the case of a portable notebook personal computer, the space inside the device is narrow, and therefore a large heat sink or a cooling fan cannot be mounted. Further, in these devices, since an integrated circuit element is mounted on a printed circuit board and a glass-reinforced epoxy resin or polyimide resin having poor thermal conductivity is used as a material of the substrate, heat of the substrate cannot be dissipated through a heat-dissipating insulating sheet as in the conventional case.
Therefore, a method is used in which a natural-cooling type or forced-cooling type heat dissipation member is provided near an integrated circuit device, and heat generated in the device is transferred to the heat dissipation member. In this way, when the element and the heat dissipating member are brought into direct contact with each other, heat transfer is deteriorated due to the unevenness of the surface, and even if the element is further mounted through the heat dissipating insulating sheet, there is a concern that: since the heat-dissipating insulation sheet is slightly inferior in flexibility, the element and the substrate are subjected to stress due to thermal expansion, and are broken.
In addition, when the heat dissipation member is to be mounted on each circuit element, an extra space is required, and it is difficult to miniaturize the apparatus, and therefore, a method of combining a plurality of elements with a single heat dissipation member and cooling the same has been adopted.
In particular, a Ball Grid Array (BGA) type CPU used in a notebook personal computer has a height lower than other elements and generates a large amount of heat, and thus a cooling method needs to be considered sufficiently.
Therefore, a high thermal conductive material having low hardness is required, which can fill various gaps generated due to the difference in height between the elements. In order to solve such a problem, a thermally conductive sheet having excellent thermal conductivity and flexibility and capable of coping with various gaps is required.
In this case, patent document 2 discloses a sheet obtained by molding a silicone resin mixed with a thermally conductive material such as a metal oxide, in which a flexible and easily deformable silicone layer is laminated on a silicone resin layer having a strength necessary for handling. Patent document 3 discloses a thermally conductive composite sheet comprising a combination of a silicone rubber layer containing a thermally conductive filler and having an Asker C hardness of 5 to 50 and a porous reinforcing material layer having pores with a diameter of 0.3mm or more. Patent document 4 discloses a sheet in which a flexible three-dimensional mesh or foam skeleton lattice surface is covered with a thermally conductive silicone rubber. Patent document 5 discloses a thermally conductive composite organic silicon wafer containing a reinforcing sheet or cloth, having adhesion on at least one surface, having an Asker C hardness of 5 to 50 and a thickness of 0.4mm or less. Patent document 6 discloses a heat dissipation spacer containing an addition reaction type liquid silicone rubber and a thermally conductive insulating ceramic powder, wherein the Asker C hardness of a cured product of the heat dissipation spacer is 25 or less and the thermal resistance of the heat dissipation spacer is 3.0 ℃/W or less.
Since these thermally conductive silicone cured products are often required to have insulating properties, alumina (aluminum oxide) is often mainly used as a thermally conductive filler in a range of thermal conductivity from 0.5 to 6W/m · K.
Alumina is generally classified into amorphous powder and spherical powder, each having advantages and disadvantages. Amorphous alumina has a high effect of improving thermal conductivity compared to spherical alumina, but has disadvantages that it is poor in filling property in silicone, and the viscosity of the material increases due to filling, and the processability deteriorates. In addition, alumina can be used in abrasives, which has a mohs hardness of 9, which is very hard. Therefore, the heat conductive silicone composition using amorphous alumina having a particle size of 10 μm or more has the following problems: if a shearing force is applied during preparation, the inner wall and the stirring blades of the stirring tank are scraped. As described above, components of the stirring vessel or the stirring blade are mixed into the heat-conductive silicone composition, and the insulation properties of the heat-conductive silicone composition and a cured product using the heat-conductive silicone composition are reduced. Further, the gap between the stirring vessel and the stirring blade becomes wide, the stirring efficiency is lowered, and even if the preparation is performed under the same conditions, a constant quality cannot be obtained. Further, there is a problem that the parts need to be frequently replaced in order to prevent this.
In order to solve this problem, there is a method using only spherical alumina powder, but spherical alumina powder is more expensive than amorphous powder, and thus there is a problem of cost increase. Further, since alumina is very heavy because its theoretical specific gravity is 3.98, the specific gravity of the composition and the cured product is increased. In recent years, electronic devices have been increasingly downsized and lightened, and in order to lighten the whole electronic device, a member unit is required to be lighter while maintaining performance in units of grams or milligrams. The use of alumina is also disadvantageous from the viewpoint of weight reduction and cost.
Examples of the filler satisfying the above requirements include ground calcium carbonate. The heavy calcium carbonate has a specific gravity of about 2.7, is lower than alumina, and is inexpensive. The Mohs hardness is as low as about 2, and the insulation property is not reduced.
However, heavy calcium carbonate has a problem that it has a low filling property in silicone and is difficult to achieve high thermal conductivity. Further, when the addition curing silicone is filled with ground calcium carbonate, there is a problem that curing inhibition occurs and a thermally conductive sheet having low hardness cannot be obtained.
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. S47-32400
Patent document 2: japanese patent laid-open publication No. 2-196453
Patent document 3: japanese patent laid-open publication No. 7-266356
Patent document 4: japanese patent laid-open publication No. H8-238707
Patent document 5: japanese laid-open patent publication No. 9-1738
Patent document 6: japanese patent laid-open publication No. 9-296114
Disclosure of Invention
Technical problem to be solved by the invention
The present invention has been made in view of the above circumstances, and an object thereof is to provide a thermally conductive silicone composition using ground calcium carbonate, which can give a thermally conductive resin molded body (thermally conductive silicone cured product) excellent in compressibility, insulation properties, thermal conductivity, and processability, and a cured product thereof.
Means for solving the problems
In order to solve the above problems, the present invention provides a thermally conductive silicone composition comprising: 100 parts by mass of an organopolysiloxane having at least 2 or more alkenyl groups in one molecule as component (a); an organohydrogenpolysiloxane having at least 2 or more hydrogen atoms directly bonded to silicon atoms as component (B) in an amount such that the number of moles of hydrogen atoms directly bonded to silicon atoms is 0.1 to 5.0 times the number of moles of alkenyl groups derived from component (a); 700 to 2,500 parts by mass of a thermally conductive filler as the component (C); a platinum group metal-based curing catalyst as component (D) in an amount of 0.1 to 2,000ppm in terms of the mass of platinum group metal elements relative to component (A); the component (C) comprises 400 to 2,000 parts by mass of (C-1) a ground calcium carbonate filler having an average particle diameter of 12 to 50 μm and 0.1 to 1,500 parts by mass of (C-2) a ground calcium carbonate filler having an average particle diameter of 0.4 to 10 μm, and the total amount of the component (C-1) and the component (C-2) is 700 to 2,500 parts by mass.
Such a thermally conductive silicone composition can provide a thermally conductive resin molded body having excellent compressibility, insulation properties, thermal conductivity, and processability.
The thermally conductive silicone composition may further contain, as the component (E), 0.01 to 300 parts by mass of any one or both of the following components relative to 100 parts by mass of the component (a):
(E-1) an alkoxysilane compound represented by the following general formula (1),
R 1 a R 2 b Si(OR 3 ) 4-a-b (1)
in the formula, R 1 Independently an alkyl group having 6 to 15 carbon atoms, R 2 Independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, R 3 Independently an alkyl group having 1 to 6 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b is an integer of 1 to 3; and
(E-2) a dimethylpolysiloxane blocked at one terminal of the molecular chain with a trialkoxysilyl group, represented by the following general formula (2),
[ chemical formula 1]
In the formula, R 4 Independently an alkyl group having 1 to 6 carbon atoms, and c is an integer of 5 to 100.
Such a thermally conductive silicone composition can provide a thermally conductive resin molded body having further excellent compressibility, insulation properties, thermal conductivity, and processability.
The heat-conductive silicone composition can further contain, as component (F), 0.1 to 100 parts by mass of a component (A) per 100 parts by mass of a component (F) having a kinematic viscosity at 23 ℃ represented by the following general formula (3) of 10 to 100,000mm 2 An organopolysiloxane per second.
[ chemical formula 2]
In the formula, R 5 Independently a monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond, and d is an integer of 5 to 2,000.
Such a thermally conductive silicone composition can provide a thermally conductive resin molded body having further excellent compressibility, insulation properties, thermal conductivity, and processability.
The heat-conductive silicone composition preferably has a viscosity of 800 pas or less at 23 ℃.
Such a heat conductive silicone composition has excellent moldability.
The present invention also provides a thermally conductive silicone cured product which is a cured product of the thermally conductive silicone composition.
Such a heat-conductive silicone cured product is excellent in compressibility, insulation properties, heat conductivity, and processability.
The heat-conductive silicone cured product preferably has a thermal conductivity of 0.7W/mK or more.
Such a heat-conductive silicone cured product can be suitably used as a heat-conductive resin molded body for heat dissipation, which is provided between a heat generating member and a heat dissipating member in an electronic device, for example.
Further, the hardness of the heat-conductive silicone cured product as measured by an Asker C hardness tester is preferably 60 or less.
Such a heat conductive silicone cured product can be deformed along the shape of the heat-radiating body, exhibits good heat-radiating characteristics, and does not apply stress to the heat-radiating body.
Further, the breakdown voltage of the heat conductive silicone cured product is preferably 10kV/mm or more.
Such a heat-conductive silicone cured product can stably ensure insulation during use.
The present invention also provides a method for producing the thermally conductive silicone composition, the method including: a first mixing step of mixing the components (A), (C) and (D), and optionally (E) and (F); and a second mixing step of adding component (B) to the obtained mixture and further mixing the mixture, wherein the first mixing step is performed by vacuum defoaming and stirring.
In the method for producing such a heat conductive silicone composition, the wettability of the composition in the mixing (kneading) step is sufficient, and a uniform composition in the form of a paste can be obtained.
Effects of the invention
As described above, in the thermally conductive silicone composition of the present invention, by using ground calcium carbonate having an average particle size of 12 to 50 μm and ground calcium carbonate having an average particle size of 0.4 to 10 μm in combination at a specific ratio, a thermally conductive silicone cured product having excellent compressibility, insulation properties, thermal conductivity, and processability and having high thermal conductivity can be provided. In particular, a cured product having a thermal conductivity of 0.7W/m · K or more can be provided, and the cured product can be suitably used as a thermally conductive resin molded body (thermally conductive silicone cured product) for heat dissipation provided between a heat generating component and a heat dissipating component in an electronic device, for example. Specifically, the present invention is particularly useful as a heat conductive material for cooling an electronic component by heat conduction, which is present at an interface between a thermal interface of a heat-generating electronic component and a heat-releasing member such as a heat sink or a circuit board.
Detailed Description
As described above, development of a thermally conductive silicone cured product (thermally conductive resin molded product) excellent in compressibility, insulation properties, thermal conductivity, and processability and a thermally conductive silicone composition capable of imparting the cured product have been desired. In particular, heavy calcium carbonate fillers have a problem that, although they can satisfy the requirements for size reduction, weight reduction, and cost reduction of electronic devices, they have a low filling property in silicone and are difficult to achieve high thermal conductivity exceeding 0.5W/m · K; further, when the addition curing silicone is filled, curing is inhibited, and a thermally conductive sheet having a desired hardness cannot be obtained.
The inventors of the present application have conducted extensive studies to achieve the above object and found that the above problems can be solved by using a ground calcium carbonate having an average particle size of 12 to 50 μm and a ground calcium carbonate having an average particle size of 0.4 to 10 μm at the same time in a specific ratio. That is, it was found that a large amount of large-particle-size ground calcium carbonate having a small specific surface area can achieve high thermal conductivity and prevent the inhibition of solidification, and the present invention was completed.
That is, the present invention relates to a thermally conductive silicone composition characterized by comprising:
100 parts by mass of an organopolysiloxane having at least 2 alkenyl groups in one molecule as component (a);
an organohydrogenpolysiloxane having at least 2 hydrogen atoms directly bonded to silicon atoms as component (B) in an amount such that the number of moles of hydrogen atoms directly bonded to silicon atoms is 0.1 to 5.0 times the number of moles of alkenyl groups derived from component (a);
700 to 2,500 parts by mass of a thermally conductive filler as the component (C);
a component (D) which is a platinum group metal curing catalyst in an amount of 0.1 to 2,000ppm in terms of the mass of the platinum group metal element relative to the component (A);
the component (C) comprises 400 to 2,000 parts by mass of a (C-1) ground calcium carbonate filler having an average particle diameter of 12 to 50 μm and 0.1 to 1,500 parts by mass of a (C-2) ground calcium carbonate filler having an average particle diameter of 0.4 to 10 μm, and
the total amount of the (C-1) and the (C-2) is 700 to 2,500 parts by mass.
The present invention will be described in detail below, but the present invention is not limited thereto.
The heat conductive silicone composition of the present invention contains, as essential components: an organopolysiloxane having at least 2 alkenyl groups in one molecule as component (a); an organohydrogenpolysiloxane having at least 2 hydrogen atoms directly bonded to silicon atoms as component (B); a thermally conductive filler as component (C); and a platinum group metal curing catalyst as component (D). The above components are explained below.
[ (A) ingredient: alkenyl-containing organopolysiloxanes
The alkenyl-containing organopolysiloxane as the component (a) is an organopolysiloxane having 2 or more alkenyl groups bonded to silicon atoms in one molecule, and is the main component of the thermally conductive silicone composition of the present invention. In general, the main chain portion is substantially composed of repeating diorganosiloxane units, and the molecular structure of the main chain portion may include a branched structure or a cyclic structure, but linear diorganopolysiloxane is preferable from the viewpoint of physical properties such as mechanical strength of a cured product.
Examples of the functional group other than the alkenyl group bonded to the silicon atom include unsubstituted or substituted monovalent hydrocarbon groups, such as alkyl groups, e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, and dodecyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and the like; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenyl; aralkyl groups such as benzyl, phenethyl, phenylpropyl, and methylbenzyl; and those in which some or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom such as fluorine, chlorine, bromine, or cyano group, for example, chloromethyl group, 2-bromoethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, chlorophenyl group, fluorophenyl group, cyanoethyl group, 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, or the like; typical groups are those having 1 to 10 carbon atoms, particularly typical groups are those having 1 to 6 carbon atoms, and unsubstituted or substituted alkyl groups having 1 to 3 carbon atoms such as methyl, ethyl, propyl, chloromethyl, bromoethyl, 3,3,3-trifluoropropyl, cyanoethyl and the like are preferred; and unsubstituted or substituted phenyl groups such as phenyl, chlorophenyl and fluorophenyl. In addition, the functional groups other than the alkenyl group bonded to the silicon atom are not limited to be all the same.
Examples of the alkenyl group include alkenyl groups having usually about 2 to 8 carbon atoms such as a vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, and the like; among them, lower alkenyl groups such as vinyl and allyl are preferable, and vinyl is particularly preferable. In addition, 2 or more alkenyl groups must be present in the molecule, and in order to improve the flexibility of the resultant cured product, it is preferable that the alkenyl groups be present so as to be bonded only to silicon atoms at the ends of the molecular chain.
The organopolysiloxane preferably has a kinematic viscosity at 23 ℃ of 10 to 100,000mm 2 In the range of 500 to 50,000mm, particularly preferably 2 In the range of/s. If the kinematic viscosity is 10mm 2 When the concentration is 100,000mm, the storage stability of the obtained composition is good 2 When the ratio is less than s, the obtained composition has good stretchability. The kinematic viscosity is a value measured using an Ostwald viscometer (Ostwald viscometer) (the same applies hereinafter).
The organopolysiloxane of component (A) can be used alone in 1 kind, or can be used in combination with 2 or more kinds of different viscosities.
[ (B) ingredient: organohydrogenpolysiloxanes
(B) The organohydrogenpolysiloxane of component (a) is an organohydrogenpolysiloxane having at least 2, preferably 2 to 100, hydrogen atoms (Si — H groups) directly bonded to silicon atoms in one molecule, and functions as a crosslinking agent of component (a). That is, the Si — H group in the component (B) is added to the alkenyl group in the component (a) by a hydrosilylation reaction promoted by a platinum group metal-based curing catalyst of the component (D) described later, thereby imparting a three-dimensional network structure having a crosslinked structure. When the number of Si-H groups in the component (B) is less than 2, the composition cannot be cured.
As the organohydrogenpolysiloxane, an organohydrogenpolysiloxane represented by the following average structural formula (4) can be used, but is not limited thereto.
[ chemical formula 3]
Wherein R 'is independently a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, but at least 2, preferably 2 to 10, R's are hydrogen atoms; e is an integer of 1 or more, preferably an integer of 10 to 200.
In the formula (4), examples of the unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond other than a hydrogen atom for R' include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl and dodecyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and the like; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenyl; aralkyl groups such as benzyl, phenethyl, phenylpropyl, and methylbenzyl; and those in which some or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom such as fluorine, chlorine, bromine, or cyano group, for example, chloromethyl group, 2-bromoethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, chlorophenyl group, fluorophenyl group, cyanoethyl group, 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, or the like; typical groups are those having 1 to 10 carbon atoms, particularly typical groups are those having 1 to 6 carbon atoms, and unsubstituted or substituted alkyl groups having 1 to 3 carbon atoms such as methyl, ethyl, propyl, chloromethyl, bromoethyl, 3,3,3-trifluoropropyl, cyanoethyl, and the like are preferred; and unsubstituted or substituted phenyl groups such as phenyl, chlorophenyl and fluorophenyl. In addition, R' is not limited to the same.
The amount of the component (B) to be added is such that the number of moles of Si — H groups derived from the component (B) is 0.1 to 5.0 moles (that is, the number of moles of hydrogen atoms directly bonded to silicon atoms is 0.1 to 5.0 times the number of moles of alkenyl groups derived from the component (a)) relative to 1 mole of alkenyl groups derived from the component (a), preferably 0.3 to 2.0 moles of Si-H groups derived from the component (B) relative to 1 mole of alkenyl groups derived from the component (a), and more preferably 0.5 to 1.0 mole of Si-H groups derived from the component (B) relative to 1 mole of alkenyl groups derived from the component (a). If the amount of the Si — H group derived from the component (B) is less than 0.1 mol based on 1 mol of the alkenyl group derived from the component (a), curing may be impossible, or the strength of the cured product may be insufficient, and the shape of the molded article may not be maintained, and further handling may be impossible. When the amount exceeds 5 mol, the cured product is not flexible and becomes brittle.
[ (C) ingredient: thermally conductive filler
The thermally conductive filler as component (C) mainly contains ground calcium carbonate and is composed of the following components (C-1) to (C-2).
(C-1) ground calcium carbonate filler having an average particle diameter of 12 to 50 μm
(C-2) ground calcium carbonate filler having an average particle diameter of 0.4 to 10 μm
In the present invention, the average particle diameter is a value of a volume-based cumulative average particle diameter (median diameter) measured by a particle size analyzer Microtrac MT3300EX manufactured by Nikkiso co.
The ground calcium carbonate filler of the component (C-1) can remarkably improve the thermal conductivity. The ground calcium carbonate has an average particle diameter of 12 to 50 μm, preferably 15 to 25 μm. If the average particle size is less than 12 μm, the effect of improving the thermal conductivity is low, and the viscosity of the composition increases to deteriorate the processability. If the average particle diameter exceeds 50 μm, the particle diameter becomes too large, and hence moldability is deteriorated. As the ground calcium carbonate filler as the component (C-1), 1 type or 2 or more types in combination can be used.
The ground calcium carbonate filler of the component (C-2) is combined with the ground calcium carbonate filler of the component (C-1) to improve the thermal conductivity and fluidity of the composition and to prevent the filler from precipitating. The average particle diameter is 0.4 to 10 μm, particularly preferably 0.8 to 9 μm. If the average particle size is less than 0.4. Mu.m, the particle size becomes too small to be handled easily, the effect of improving the thermal conductivity is also low, and the viscosity of the composition is increased to deteriorate the processability. If the average particle size exceeds 10 μm, the effect of improving the thermal conductivity and fluidity of the composition and the effect of preventing the precipitation of the filler by the combination with the component (C-1) are impaired. As the ground calcium carbonate filler as the component (C-2), 1 type or 2 or more types in combination can be used.
The amount of the component (C-1) blended is 400 to 2,000 parts by mass, preferably 800 to 1,500 parts by mass, per 100 parts by mass of the component (A). If the amount of the additive is too small, it is difficult to improve the thermal conductivity; if the amount is too large, the composition loses fluidity and moldability is impaired.
The amount of the component (C-2) blended is 0.1 to 1,500 parts by mass, preferably 200 to 800 parts by mass, per 100 parts by mass of the component (A). If the amount is less than 0.1 part by mass, it is difficult to improve the thermal conductivity and the fluidity, and there is a concern that the filler may precipitate. If the blending amount exceeds 1,500 parts by mass, the composition loses fluidity and moldability is impaired.
Further, the blending amount of the component (C) (i.e., the total blending amount of the component (C-1) and the component (C-2)) needs to be 700 to 2,500 parts by mass, preferably 1,200 to 1,600 parts by mass, based on 100 parts by mass of the component (A). When the blending amount of the (C) component is less than 700 parts by mass, the obtained composition has poor thermal conductivity, and the viscosity of the composition becomes extremely low viscosity, resulting in deterioration of storage stability; when the amount of the component (C) is more than 2,500 parts by mass, the composition is poor in stretchability and gives a molded article having high hardness or low strength.
As described above, the above-mentioned effects of the present invention can be more advantageously and reliably exhibited by blending the ground calcium carbonate filler (C-1) having an average particle diameter of 12 to 50 μm and the ground calcium carbonate filler (C-2) having an average particle diameter of 0.4 to 10 μm in the above-mentioned specific ratio and using the component (C) (consisting of (C-1) and (C-2)) in the above-mentioned blending ratio.
[ (D) ingredient: platinum group Metal curing catalysts
(D) The platinum group metal-based curing catalyst of component (a) is not particularly limited as long as it is a catalyst for promoting an addition reaction between the alkenyl group derived from component (a) and the Si — H group derived from component (B), and known catalysts can be used as the catalyst for the hydrosilylation reaction. Specific examples thereof include simple platinum group metals such as platinum (including platinum black), rhodium, and palladium; h 2 PtCl 4 ·nH 2 O、H 2 PtCl 6 ·nH 2 O、NaHPtCl 6 ·nH 2 O、KHPtCl 6 ·nH 2 O、Na 2 PtCl 6 ·nH 2 O、K 2 PtCl 4 ·nH 2 O、PtCl 4 ·nH 2 O、PtCl 2 、Na 2 HPtCl 4 ·nH 2 Platinum chloride, chloroplatinic acid, and chloroplatinic acid salts such as O (wherein n in the above formula is an integer of 0 to 6, preferably 0 or 6); alcohol-modified chloroplatinic acid (see, e.g., U.S. Pat. No. 3,220,972 specification), a complex of chloroplatinic acid with an olefin (see, e.g., U.S. Pat. No. 3,159,601, U.S. Pat. No. 3,159,662, and U.S. Pat. No. 3,775,452); a substance having platinum group metals such as platinum black and palladium supported on a carrier such as alumina, silica and carbon; a rhodium-olefin complex; tris (triphenylphosphine) rhodium chloride (wilkinson's catalyst); complexes of platinum chloride, chloroplatinic acid or chloroplatinic acid salts with vinyl-containing siloxanes, especially vinyl-containing cyclic siloxanes, and the like.
The amount of the component (D) used is 0.1 to 2,000ppm, preferably 50 to 1,000ppm, in terms of the mass of the platinum group metal element, relative to the component (A). If less than 0.1ppm, sufficient catalytic activity cannot be obtained; even if it exceeds 2,000ppm, the effect of accelerating the addition reaction is not enhanced, but the cost is increased, and the catalyst remains in the cured product, so that there is a concern that the insulation property may be lowered.
[ (E) ingredient: surface treating agent
The surface treatment agent of component (E) can be blended in the thermally conductive silicone composition of the present invention in the preparation of the composition, and the purpose of the surface treatment agent is to perform hydrophobic treatment on the thermally conductive filler of component (C) to improve wettability with the organopolysiloxane of component (a) and to uniformly disperse the thermally conductive filler of component (C) in the matrix composed of component (a). Further, the component (E) can cover the surface of the component (C) and suppress occurrence of curing inhibition. As the component (E), the following components (E-1) and (E-2) are particularly preferable.
The component (E-1) is an alkoxysilane compound represented by the following general formula (1).
R 1 a R 2 b Si(OR 3 ) 4-a-b (1)
In the formula, R 1 Independently an alkyl group having 6 to 15 carbon atoms, R 2 Independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, R 3 Independently an alkyl group having 1 to 6 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b is an integer of 1 to 3.
In the above general formula (1), R is represented by 1 Examples of the alkyl group include hexyl, octyl, nonyl, decyl, dodecyl, and tetradecyl. If the radical R is 1 When the number of carbon atoms of the alkyl group is in the range of 6 to 15, the wettability of the component (a) is sufficiently improved, the workability is good, and the low-temperature characteristics of the composition are good.
As a group consisting of R 2 Examples of the unsubstituted or substituted monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl and dodecyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and the like; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenyl; aralkyl groups such as benzyl, phenethyl, phenylpropyl, and methylbenzyl; and those in which some or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom such as fluorine, chlorine, bromine, or cyano group, for example, chloromethyl group, 2-bromoethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, chlorophenyl group, fluorophenyl group, cyanoethyl group, 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, or the like; a typical group is a group having 1 to 10 carbon atoms, and a typical group is a group having 1 to 6 carbon atoms, and preferably an unsubstituted or substituted alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group, a chloromethyl group, a bromoethyl group, a 3,3,3-trifluoropropyl group, and a cyanoethyl group; and unsubstituted or substituted phenyl groups such as phenyl, chlorophenyl and fluorophenyl. As R 3 Examples thereof include methyl, ethyl, propyl, butyl and hexyl.
The component (E-2) is dimethylpolysiloxane having a molecular chain blocked at one end with a trialkoxysilyl group, represented by the following general formula (2).
[ chemical formula 4]
In the formula, R 4 Independently an alkyl group having 1 to 6 carbon atoms, and c is an integer of 5 to 100, preferably an integer of 5 to 70, and particularly preferably an integer of 10 to 50.
The surface-treating agent as the component (E) may be either one of the components (E-1) and (E-2), or a combination of both may be blended.
The amount of the component (E) to be blended is preferably 0.01 to 300 parts by mass, particularly preferably 0.1 to 200 parts by mass, based on 100 parts by mass of the component (A). If the blending ratio of the present component is within the above range, oil separation is not induced.
[ (F) ingredient: property-imparting agent
For the purpose of imparting properties such as adjusting the viscosity of the heat conductive silicone composition, the heat conductive silicone composition of the present invention may be added with a component (F) having a kinematic viscosity at 23 ℃ represented by the following general formula (3) of 10 to 100,000mm 2 An organopolysiloxane per second. (F) The components can be used singly or in combination of 2 or more.
[ chemical formula 5]
In the formula, R 5 Independently a monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond, and d is an integer of 5 to 2,000.
In the above general formula (3), R 5 Independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond. As R 5 Examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl and dodecyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and the like; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenyl; benzyl, benzeneAralkyl groups such as ethyl, phenylpropyl, and methylbenzyl; and those in which some or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom such as fluorine, chlorine, bromine, or cyano group, for example, chloromethyl group, 2-bromoethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, chlorophenyl group, fluorophenyl group, cyanoethyl group, 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, or the like; a typical group is a group having 1 to 10 carbon atoms, and a typical group is a group having 1 to 6 carbon atoms, and preferably an unsubstituted or substituted alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group, a chloromethyl group, a bromoethyl group, a 3,3,3-trifluoropropyl group, and a cyanoethyl group; and unsubstituted or substituted phenyl such as phenyl, chlorophenyl, fluorophenyl and the like; methyl and phenyl are particularly preferred.
From the viewpoint of the required viscosity, d is preferably an integer of 5 to 2,000, and particularly preferably an integer of 10 to 1,000.
The component (F) has a kinematic viscosity of 10 to 100,000mm at 23 DEG C 2 S, preferably 100 to 10,000mm 2 And s. If the kinematic viscosity is 10mm 2 When the amount is more than s, oil bleeding hardly occurs in the cured product of the obtained composition. If the kinematic viscosity is 100,000mm 2 The flexibility of the obtained thermally conductive silicone composition is suitable when the concentration is less than s.
When component (F) is added to the heat-conductive silicone composition of the present invention, component (F) is 0.1 to 100 parts by mass, preferably 1 to 50 parts by mass, per 100 parts by mass of component (a). When the amount of addition is within this range, the thermally conductive silicone composition before curing can easily maintain good fluidity and workability, and the thermally conductive filler of component (C) can be easily filled in the composition.
[ (G) ingredient: reaction control agent
The thermally conductive silicone composition of the present invention can further contain an addition reaction control agent as component (G). The addition reaction controlling agent can be any known addition reaction controlling agent used in general addition reaction curable silicone compositions. Examples thereof include acetylene compounds such as 1-ethynyl-1-hexanol, 3-butyn-1-ol and ethynylmethylenemethanol (ethynylmethylidene carbinol); or various nitrogen compounds; an organic phosphorus compound; an oxime compound; organochlorine compounds, and the like.
The amount of the component (G) to be used in the blending is preferably about 0.01 to 1 part by mass, and particularly preferably about 0.1 to 0.8 part by mass, based on 100 parts by mass of the component (A). When the amount is such an amount, the curing reaction can be sufficiently performed without impairing the molding efficiency.
[ other ingredients ]
Other ingredients may be further blended as necessary in the thermally conductive silicone composition of the present invention. For example, a heat resistance improver such as iron oxide or cerium oxide can be blended; viscosity modifiers such as silica; a colorant; a release agent, and the like.
[ viscosity of composition ]
The viscosity of the heat-conductive silicone composition of the present invention is 800Pa · s or less, preferably 700Pa · s or less at 23 ℃. Such a viscosity does not impair moldability. The lower limit is not particularly limited, and may be, for example, 60Pa · s or more. In the present invention, the viscosity is measured by using a B-type viscosity agent.
[ method for producing Heat-conductive Silicone cured product ]
The curing conditions for molding the heat-conductive silicone composition may be the same as those of known addition reaction-curable silicone rubber compositions, and for example, the heat-conductive silicone composition may be sufficiently cured at room temperature, or may be heated as needed. Addition curing is preferably carried out at 100 to 120 ℃ for 8 to 12 minutes. Such a silicone cured product of the present invention has excellent thermal conductivity.
[ thermal conductivity of thermally conductive resin molded article ]
The thermal conductivity of the thermally conductive resin molded product (thermally conductive silicone cured product) in the present invention is preferably 0.7W/m · K or more, particularly preferably 0.9W/m · K or more, as measured at 25 ℃ by a transient plane heat source method (Hot Disk) method. The upper limit is not particularly limited, and may be, for example, 1.4W/m.K or less.
[ breakdown Voltage of thermally conductive resin molded article ]
The breakdown voltage of the thermally conductive resin molded article in the present invention is preferably 10kV or more, and more preferably 13kV or more, as measured by measuring the breakdown voltage of a molded article having a thickness of 1mm in accordance with JIS K6249. When the sheet has a breakdown voltage of 10kV/mm or more, insulation can be stably secured in use. The upper limit is not particularly limited, and may be, for example, 20kV/mm or less. In addition, such breakdown voltage can be adjusted by adjusting the kind or purity of the filler.
[ hardness of thermally conductive resin molded article ]
The hardness of the thermally conductive resin molded body in the present invention is 60 or less, preferably 40 or less, more preferably 30 or less, and preferably 5 or more as measured at 25 ℃ by an Asker C hardness tester. If the hardness is 60 or less, the heat sink is easily deformed along the shape of the heat-receiving body, exhibits good heat dissipation characteristics, and does not apply stress to the heat-receiving body. Further, the hardness can be adjusted by adjusting the crosslinking density by changing the ratio of the component (a) to the component (B).
[ method for producing Heat-conductive Silicone composition ]
The heat conductive silicone composition of the present invention can be prepared by uniformly mixing the above-described respective ingredients in accordance with a conventional method, preferably: a first mixing step of mixing the component (A), the component (C), the component (D), and optionally the component (E) and the component (F); and a second mixing step of subsequently adding the component (B) to the obtained mixture and further mixing the mixture to obtain a heat-conductive silicone composition, wherein the heat-conductive silicone composition is mixed by performing vacuum defoaming stirring in the first mixing step. By mixing (kneading) the specific components by previously performing vacuum defoaming and stirring (first mixing step), the wettability of the composition becomes sufficient, and a paste-like uniform composition can be obtained. The mixing method in the second mixing step is not particularly limited as long as uniform mixing is possible, and mixing (kneading) can be performed by performing vacuum defoaming stirring as in the first mixing step. In the present specification, such mixing is sometimes referred to as "kneading".
As described above, the heat-conductive silicone composition of the present invention is characterized by containing the above-mentioned components (A) to (D) as essential components, in particular, a ground calcium carbonate filler (C-1) having an average particle diameter of 12 to 50 μm and a ground calcium carbonate filler (C-2) having an average particle diameter of 0.4 to 10 μm are blended in a specific ratio as the component (C), and the component (C) (consisting of the components (C-1) and (C-2)) is used in a specific blending ratio. Further, by using the ground calcium carbonate having different average particle diameters at a specific ratio, a thermally conductive silicone cured product having excellent compressibility, insulation properties, thermal conductivity, and processability and having high thermal conductivity can be provided. In particular, a cured product having a thermal conductivity of 0.7W/m · K or more can be provided, and the cured product can be suitably used as a thermally conductive resin molded body (thermally conductive silicone cured product) for heat dissipation provided between a heat generating component and a heat dissipating component in an electronic device, for example. Specifically, the present invention is particularly useful as a heat conductive material for cooling an electronic component by heat conduction, which is present at an interface between a thermal interface of a heat-generating electronic component and a heat-releasing member such as a heat sink or a circuit board.
Examples
The present invention will be specifically described below by way of examples and comparative examples, but the present invention is not limited thereto. The kinematic viscosity was measured at 23 ℃ with an Ostwald viscometer. Further, the average particle diameter is a value of a cumulative average particle diameter (median diameter) on a volume basis measured using a particle size analyzer Microtrac MT3300EX manufactured by Nikkiso co.
The components (a) to (G) used in the following examples and comparative examples are as follows.
(A) The components:
an organopolysiloxane represented by the following formula (5).
[ chemical formula 6]
Wherein X is a vinyl group, and f is a number which gives the following kinematic viscosity.
Kinematic viscosity: 600mm 2 /s
(B) The components:
an organohydrogenpolysiloxane represented by the following formula (6).
[ chemical formula 7]
In the formula, g is 28, h is 2.
(C) The components:
the average particle size of the ground calcium carbonate filler is as follows.
(C-1) ground calcium carbonate Filler having an average particle diameter of 16.6 μm
(C-2 a) ground calcium carbonate filler having an average particle diameter of 6.9. Mu.m
(C-2 b) ground calcium carbonate Filler having an average particle diameter of 2.9 μm
(C-2C) ground calcium carbonate Filler having an average particle diameter of 10 μm
(D) The components:
5% by mass of 2-ethylhexanol chloroplatinic acid solution
(E) The components: (E-2) component
A dimethylpolysiloxane having an average degree of polymerization of 30 and terminated with trimethoxysilyl groups at one end represented by the following formula (7).
[ chemical formula 8]
(F) Composition (I)
A dimethylpolysiloxane represented by the following formula (8) is used as a plasticizer.
[ chemical formula 9]
Wherein j is 80.
(G) The components:
ethynylmethylenglycol as addition reaction control agent.
Examples 1 to 3 and comparative examples 1 to 2
In examples 1 to 3 and comparative examples 1 to 2, compositions were prepared in the following manner using the above components (a) to (G) and other components (internal addition type release agent) in the predetermined amounts shown in table 1, and were molded and cured, and then the viscosity, the presence or absence of curing inhibition, the thermal conductivity, the hardness, the breakdown voltage, and the specific gravity of the cured product of the compositions were observed according to the following evaluation methods. The results are also shown in Table 1. In table 1, "H/Vi" is a ratio of the number of moles of hydrogen atoms (Si — H groups) directly bonded to silicon atoms to the number of moles of alkenyl groups derived from component (a).
[ preparation of composition ]
Components (A), (C) to (F) were added in predetermined amounts as shown in examples 1 to 3 and comparative examples 1 to 2 in Table 1 below, and an effective amount of phenyl-modified silicone oil KF-54 manufactured by Shin-Etsu Chemical Co., ltd. Was further added as an internal addition type release agent for promoting detachment from the separator, and kneaded for 90 minutes while performing vacuum defoaming with a planetary mixer.
The components (B) and (G) were added in the amounts specified in examples 1 to 3 and comparative examples 1 to 2 of Table 1 below, and kneaded for 30 minutes to obtain a composition.
[ Molding curing method ]
The compositions obtained in examples 1 to 3 and comparative examples 1 to 2 were injected into a mold of 60 mm. Times.60 mm. Times.6 mm, and molded and cured at 120 ℃ for 10 minutes using a molding machine.
[ evaluation method ]
Viscosity of the composition:
the viscosities of the compositions obtained in examples 1 to 3 and comparative examples 1 to 2 were measured at 23 ℃ with a type B viscometer.
Whether cure inhibition occurred:
the compositions were heat-treated to determine whether or not the compositions obtained in examples 1 to 3 and comparative examples 1 to 2 inhibited curing.
Thermal conductivity:
the compositions obtained in examples 1 to 3 and comparative examples 1 to 2 were cured into a sheet shape of 6mm thickness using a molding machine at 120 ℃ for 10 minutes, and the thermal conductivity of the sheet was measured using a thermal conductivity tester (trade name: TPS-2500S, KYOTO ELECTRONICS MANUFURI ACTNG CO., LTD., manufactured) using 2 sheets.
Hardness:
the compositions obtained in examples 1 to 3 and comparative examples 1 to 2 were cured into 6mm thick sheets in the same manner as described above, and 2 sheets were stacked and measured by an Asker C hardness tester.
Breakdown voltage:
the compositions obtained in examples 1 to 3 and comparative examples 1 to 2 were cured into a sheet having a thickness of 1mm by using a molding machine under conditions of 120 ℃ and 10 minutes, and the breakdown voltage was measured according to JIS K6249.
Specific gravity:
the compositions obtained in examples 1 to 3 and comparative examples 1 to 2 were cured into a sheet shape having a thickness of 1mm by using a molding machine under conditions of 120 ℃ and 10 minutes, and the specific gravity of the cured product was measured by the underwater substitution method.
[ Table 1]
As shown in comparative example 1, if the total mass part of the thermally conductive filler exceeds 2,500 parts by mass with respect to 100 parts by mass of the component (a), the wettability of the composition is insufficient, and a uniform composition in the form of a paste cannot be obtained. As shown in comparative example 2, when the amount of the (C-1) component is less than 400 parts by mass and the filling amount of the (C-2) component is increased for higher heat conductivity, curing inhibition occurs. In comparative example 1, since the composition was not in the form of a paste, it was not possible to evaluate whether or not curing was inhibited and whether or not curing was inhibited; in comparative example 2, since curing inhibition occurred, thermal conductivity and subsequent evaluation could not be performed.
On the other hand, as shown in examples, when the component (C) in which the components (C-1) and (C-2) are blended at a specific ratio is used, the viscosity of the composition, the thermal conductivity of the cured product, the hardness, the specific gravity, and the breakdown voltage are all favorable results.
The present invention is not limited to the above embodiments. The above embodiments are merely illustrative, and any embodiments having substantially the same configuration as the inventive concept described in the claims of the present invention and exhibiting the same operational effects are included in the technical scope of the present invention.
Claims (7)
1. A thermally conductive silicone composition, comprising:
100 parts by mass of an organopolysiloxane having 2 or more alkenyl groups in one molecule as component (a);
an organohydrogenpolysiloxane having 2 or more hydrogen atoms directly bonded to silicon atoms as component (B) in an amount such that the number of moles of hydrogen atoms directly bonded to silicon atoms is 0.1 to 5.0 times the number of moles of alkenyl groups derived from component (a);
700 to 2,500 parts by mass of a thermally conductive filler as the component (C);
a platinum group metal-based curing catalyst as component (D) in an amount of 0.1 to 2,000ppm in terms of the mass of platinum group metal elements relative to component (A);
0.01 to 300 parts by mass of any one or both of the following components as the component (E):
(E-1) an alkoxysilane compound represented by the following general formula (1),
R 1 a R 2 b Si(OR 3 ) 4-a-b (1)
in the formula, R 1 Independently an alkyl group having 6 to 15 carbon atoms, R 2 Independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, R 3 Independently an alkyl group having 1 to 6 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b is an integer of 1 to 3; and
(E-2) a dimethylpolysiloxane capped at one terminal of the molecular chain with a trialkoxysilyl group, represented by the following general formula (2),
[ chemical formula 1]
In the formula, R 4 Independently an alkyl group having 1 to 6 carbon atoms, c is an integer of 5 to 100;
0.1 to 100 parts by mass of a component (F) represented by the following general formula (3) and having a kinematic viscosity at 23 ℃ of 10 to 100,000mm 2 (ii) an organopolysiloxane as per the mass fraction,
[ chemical formula 2]
In the formula, R 5 Independently a monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond, and d is an integer of 5 to 2,000;
the component (C) comprises 400 to 2,000 parts by mass of a (C-1) ground calcium carbonate filler having an average particle diameter of 12 to 50 μm and 0.1 to 1,500 parts by mass of a (C-2) ground calcium carbonate filler having an average particle diameter of 0.4 to 10 μm, and
the total amount of (C-1) and (C-2) is 700 to 2,500 parts by mass.
2. The thermally conductive silicone composition according to claim 1, characterized in that the viscosity at 23 ℃ is 800Pa "s or less.
3. A thermally conductive silicone cured product, characterized by being a cured product of the thermally conductive silicone composition according to claim 1 or 2.
4. The thermally conductive cured silicone material according to claim 3, having a thermal conductivity of 0.7W/m "K or more.
5. The thermally conductive silicone cured product according to claim 3, wherein the hardness is 60 or less as measured by an Asker-C hardness tester.
6. The thermally conductive silicone cured product according to claim 3, wherein the breakdown voltage is 10kV/mm or higher.
7. A method for producing a thermally conductive silicone composition according to claim 1 or 2, characterized by comprising:
a first mixing step of mixing the component (A), the component (C) and the component (D), and the component (E) and the component (F); and
a second mixing step of adding component (B) to the obtained mixture and further mixing the mixture to obtain the heat-conductive silicone composition,
in the first mixing step, mixing is performed by performing vacuum defoaming stirring.
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| PCT/JP2019/030982 WO2020084868A1 (en) | 2018-10-23 | 2019-08-06 | Thermally conductive silicone composition and cured product thereof |
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- 2019-08-06 CN CN201980060877.0A patent/CN112714784B/en active Active
- 2019-08-06 KR KR1020217006906A patent/KR20210080351A/en unknown
- 2019-08-14 TW TW108128867A patent/TWI813738B/en active
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Also Published As
| Publication number | Publication date |
|---|---|
| WO2020084868A1 (en) | 2020-04-30 |
| JP2020066670A (en) | 2020-04-30 |
| JP6957435B2 (en) | 2021-11-02 |
| KR20210080351A (en) | 2021-06-30 |
| TWI813738B (en) | 2023-09-01 |
| TW202016219A (en) | 2020-05-01 |
| CN112714784A (en) | 2021-04-27 |
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