JP2003313431A - Heat-conductive resin composition, sheet, and electronic part, semiconductor device, display, and plasma display panel prepared by using the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant heat-conductive resin composition which has a high heat conductivity and is soft and excellent in adhesiveness; a heat- conductive sheet prepared from the same; the methods for producing the composition and the sheet; and an electronic part, a semiconductor device, a display, and a plasma display panel prepared by using the composition or the sheet. <P>SOLUTION: The composition contains a thermoplastic elastomer, a plasticizer, a tackifier, and aluminum hydroxide and has a high heat conductivity and excellent softness, flame retardance, and adhesiveness. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermally conductive composition having flexibility, thermal conductivity, and adhesiveness which is excellent in flame retardancy, a thermally conductive sheet using the same, and compositions and sheets thereof. The present invention also relates to a manufacturing method, an electronic component, a semiconductor device, a display device, and a plasma display using the manufacturing method. More specifically, a highly heat-conductive composition used to dissipate and soak heat from an electronic component, a semiconductor device, and a display device that generate heat, a high-thermal-conductivity sheet, an electronic component, a semiconductor device, a display device, and a plasma display using them. Regarding the panel.

[0002]

2. Description of the Related Art In recent years, power consumption has been steadily increasing with the increase in integration and density of electronic components, and the generated heat is efficiently radiated to reduce the temperature rise of electronic component elements. Has become an important issue. For example, in an electronic component (for example, a personal computer, various devices such as a central processing element such as a mobile phone, a power transistor, etc.) and a display device (for example, a display device using a plasma display panel or an organic EL), heat is removed, Soaking is an important issue. This is because electronic components and display devices that generate heat lead to deterioration, malfunction, failure, etc. of components as the temperature rises, or damage due to temperature disproportionation. Therefore, in order to remove heat from these heat-generating components and display devices, or to even out the temperature difference within the same component or within the device, a heat conductive composition that transfers heat to various heat sinks, heat sinks, housings, etc. Items are processed into sheets and used. In addition to thermal conductivity, the properties required for this thermally conductive composition include flexibility, adhesion, durability, etc., but in recent years many electronic products have been used for home appliances. Accordingly, it is required to be flame retardant.

Particularly in a plasma display panel, the panel is large, and accordingly, a large amount of heat conductive sheets are used, so that flame retardancy is particularly important.

Various types of such thermally conductive compositions have been proposed, for example, Japanese Patent Laid-Open No. 2000-21985.
JP-A-2000-290615 and JP-A-2000-290615 disclose heat-dissipating adhesive sheets for plasma display panels, but they are not flame-retardant. JP 2001-1068 A
Although Japanese Patent Laid-Open No. 65 uses a metal hydrate, it has a problem that flame retardancy and flexibility are not compatible with each other. Furthermore, in comparison with magnesium hydroxide shown in the examples,
There is no example of aluminum hydroxide which has a large endothermic amount when decomposed and is inexpensive. JP 2001-310974 A
The publication discloses a heat conductive sheet using a synthetic rubber resin, but it is not flame retardant as well.

In Japanese Patent Laid-Open No. 2000-315424,
Although flame retardancy is improved by using metal hydrate and red phosphorus, flame retardants have recently been restricted due to environmental issues such as phosphorus and halogen flame retardants, and their use is shunned. Tend. Halogen-based flame retardants may generate dioxins upon combustion, and phosphorus-based flame retardants have problems such as marine pollution such as eutrophication and poor water resistance.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, and has high thermal conductivity, flexibility, excellent adhesion, flame retardancy, and excellent environmental resistance. Another object is to provide a thermally conductive composition. Further, it is an object to provide a heat conductive sheet using the composition. It is an object of the present invention to provide a method for producing such a heat conductive composition and a heat conductive sheet. An object is to provide an electronic component, a semiconductor device, a display device, and a plasma display panel using a heat conductive composition or a heat conductive sheet.

[0007]

Means for Solving the Problems As a result of intensive studies conducted by the present inventor in view of the above situation, a composition containing aluminum hydroxide powder is excellent in high thermal conductivity, flexibility, flame retardancy and adhesion. Therefore, the present invention has been completed.
That is, the present invention relates to the following.

[1] Aluminum hydroxide powder, plasticizer,
A thermally conductive composition comprising a tackifier and a thermoplastic elastomer.

[2] The content of the aluminum hydroxide powder is 70% by mass to 85% of the total amount of the aluminum hydroxide powder, the plasticizer, the tackifier and the thermoplastic elastomer.
The heat conductive composition according to [1], which is in the range of mass%.

[3] The heat conductive composition as described in [1] or [2], wherein the aluminum hydroxide powder has an linseed oil absorption of 20 ml / 100 g or less.

[4] The aluminum hydroxide powder contains 70% by mass or more of the aluminum hydroxide powder having a particle diameter in the range of 0.5 to 150 μm based on the aluminum hydroxide powder. The heat conductive composition according to any one of [3].

[5] Aluminum hydroxide powder having a particle diameter in the range of 35 to 150 μm is 5.0 to 90.0 mass% of the aluminum hydroxide powder.
The aluminum hydroxide powder contained in the aluminum hydroxide powder having a particle diameter in the range of 10 to 35 μm is 5.0 to 9%.
The heat conductive composition as described in [4], which is an aluminum hydroxide powder containing 0.0% by mass.

[6] Aluminum hydroxide powder having a particle diameter in the range of 35 to 150 μm is 5.0 to 90.0 mass% of the aluminum hydroxide powder.
The aluminum hydroxide powder contained in the aluminum hydroxide powder having a particle diameter in the range of 10 to 35 μm is 5.0 to 9%.
An aluminum hydroxide powder containing 0.0 mass% of aluminum hydroxide powder having a particle size in the range of 0.5 to 10 μm and 1 to 90 mass% of aluminum hydroxide powder. The heat conductive composition according to [4].

[7] Aluminum hydroxide powder having an average particle size in the range of 35 to 150 μm is 5.0 to 90.0% by mass of the aluminum hydroxide powder and the average particle size is The aluminum hydroxide powder in the range of 10 to 35 μm is used as the aluminum hydroxide powder in 5.
The heat conductive composition as described in [4] or [5], which contains an aluminum hydroxide powder mixed in an amount of 0 to 90.0 mass%.

[8] Aluminum hydroxide powder having an average particle diameter in the range of 35 to 150 μm is 5.0 to 90.0 mass% of the aluminum hydroxide powder, and the average particle diameter is Aluminum hydroxide powder in the range of 10 to 35 μm is
90.0% by mass and an aluminum hydroxide powder having an average particle diameter in the range of 0.5 to 10 μm mixed in an amount of 1 to 90% by mass of the aluminum hydroxide powder. The heat conductive composition according to [4] or [6].

[9] Aluminum hydroxide powder is BET
The aluminum hydroxide powder having a specific surface area of 1.0 m ² / g or less and an average particle diameter of 35 to 150 μm is added to 5.0 to 90.0 mass% of the aluminum hydroxide powder and the BET specific surface area thereof. Aluminum hydroxide powder having an average particle diameter of 2.0 m ² / g or less and an average particle diameter in the range of 10 to 35 μm is 5.0 to 90.0% of aluminum hydroxide powder.
The heat conductive composition as described in [4] or [5], which contains an aluminum hydroxide powder mixed in mass%.

[10] Aluminum hydroxide powder is BE
T specific surface area is 1.0m²/ G or less and its average particle size
Hydroxide powder having a range of 35 to 150 μm
5.0-90.0 mass of aluminum hydroxide powder
%, BET specific surface area is 2.0 m ²/ G or less and flat
Aluminum hydroxide having a uniform particle size in the range of 10 to 35 μm
The aluminum powder is aluminum hydroxide powder 5.0 to 90.0
Mass% and BET specific surface area of 3.0 m²/ G or less
Hydroxide whose average particle size is in the range of 0.5 to 10 μm
1 to 9 of aluminum hydroxide powder to aluminum hydroxide powder
It should contain aluminum hydroxide powder mixed with 0% by mass.
[4] or [6], which is characterized in that
A product.

[11] Particle diameter Dbet calculated by sphere approximation where BET specific surface area of all or part of aluminum hydroxide powder is S (where Dbet is calculated as Dbet = 6 / (S × ρ)) Ρ is the specific gravity of aluminum hydroxide.)
The ratio (aggregation degree) D / Dbet of the average particle diameter D is less than 3, and the heat conductive composition according to any one of [1] to [10].

[12] The heat conductive composition as described in any one of [1] to [11], wherein the plasticizer is a paraffin oil and / or a naphthene oil.

[13] The content of the plasticizer is 1-2 in the composition.
It is 0 mass%, The heat conductive composition in any one of [1]-[12] characterized by the above-mentioned.

[14] The tackifier is characterized in that it is at least one tackifier selected from rosin-based, terpene-based, and petroleum-based [1].
The thermally conductive composition according to any of [13].

[15] The heat conductive composition as described in any one of [1] to [14], wherein the content of the tackifier is in the range of 1 to 20% by mass of the composition.

[16] Any one of [1] to [15], wherein the thermoplastic elastomer is at least one elastomer selected from styrene type, polyester type, polyurethane type and olefin type. The heat conductive composition according to.

[17] The heat conductive composition according to any one of [1] to [16], wherein the softening temperature or melting temperature of the heat conductive plastic is 200 ° C. or lower.

[18] The content of the thermoplastic elastomer is in the range of 1 to 20% by mass of the composition [1] to [17].
The thermally conductive composition according to any one of 1.

[19] The heat conductive composition as described in any one of [1] to [18], which has a heat conductivity of 0.5 W / m · K or more.

[20] Characterized by kneading [1]
~ A method for producing the heat conductive composition according to any one of [19].

[21] A heat conductive sheet comprising the heat conductive composition according to any one of [1] to [19].

[22] The thickness of the heat conductive composition is 0.1 to
The heat conductive sheet according to [21], which has a sheet shape of 3 mm.

[23] The heat conductive sheet according to [21] or [22], characterized in that the heat conductive sheet when processed to a thickness of 1 mm satisfies any of UL94 standards.

[24] The heat conductive sheet according to any of [21] to [23], which has a hardness of 70 or less according to Asker C.

[25] A method for producing a heat conductive sheet, characterized in that the heat conductive composition according to any one of [1] to [19] is formed into a sheet of 0.3 to 1 mm.

[26] An electronic component in which the heat conductive sheet according to any one of [21] to [24] is provided between a heating element and a radiator.

[27] A semiconductor device in which the heat conductive sheet according to any one of [21] to [24] is provided between a heating element and a radiator.

[28] A display device in which the heat conductive sheet according to any one of [21] to [24] is provided between a heating element and a radiator.

[29] A plasma display panel using the heat conductive sheet according to any of [21] to [24].

[30] Dissipation and / or heat dissipation of electronic parts, semiconductor devices, display devices or plasma display panels, characterized by using the heat conductive composition according to any one of [1] to [19]. Soaking method.

[31] Dissipation and / or leveling of electronic parts, semiconductor devices, display devices or plasma display panels, characterized by using the heat conductive sheet according to any one of [21] to [24]. Thermalization method.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. First, each component of the heat conductive composition of the present invention will be described.

The aluminum hydroxide powder used in the present invention is not particularly limited, and known ones can be used. In the present invention, aluminum hydroxide is a flame retardant and acts as a heat conductive filler. The endothermic amount of aluminum hydroxide is about 1.97 kJ / g, which is about 1.97 of magnesium hydroxide.
31 kJ / g, about 0.93 kJ / g of calcium hydroxide
It has a large value as compared with, and has a characteristic that the flame retardant effect is high.

The content of the aluminum hydroxide powder is preferably 70% by mass or more and 85% by mass or less, more preferably 80% by mass or more based on the composition. When it is less than 70% by mass, flame retardancy becomes difficult to obtain, and when it exceeds 85% by mass, flexibility of the composition is difficult to obtain.

The aluminum hydroxide powder preferably has a linseed oil absorption of 20 ml / 100 g or less. The linseed oil absorption amount is the amount of oil until the linseed oil is dropped onto 5 g of aluminum hydroxide powder and can be spirally wound using a spatula.
The amount converted to 0 g is shown (JIS K5101). When the linseed oil absorption is more than 20 ml / 100 g, there are problems that the composition cannot be uniformly kneaded when kneaded with the resin, the fluidity of the composition when kneading is deteriorated, the strength is lowered, and the composition cannot be processed into a sheet.

The aluminum hydroxide powder used in the present invention is such that the content of the aluminum hydroxide powder having a particle diameter in the range of 0.5 to 150 μm is 70% by mass or more of the aluminum hydroxide powder used. Preferably there is. When there are many powders with a particle size of more than 150 μm, problems such as difficulty in obtaining strength when the composition is made into a sheet and difficulty in obtaining flame retardancy occur, and when there are many powders with a particle size of less than 0.5 μm. Has problems such as difficulty in obtaining flexibility of the composition. The content ratio of the aluminum hydroxide powder having a particle diameter in the range of 0.5 to 150 μm is more preferably 80% by mass or more, and further preferably 90% by mass or more.

In the present invention, when the particle size and average particle size of the aluminum hydroxide powder are described as A to B μm, A
It means that it is not less than μm and less than Bμm.

The aluminum hydroxide powder having a somewhat wide particle size distribution can reduce the viscosity during kneading, and as a result, can be highly filled easily. That is, the aluminum hydroxide powder used in the present invention has a particle size of 35.
The content of aluminum hydroxide powder in the range of ˜150 μm is 5.0 to 90.0 mass%, and the particle size is 10 to 35 μm.
Aluminum hydroxide powder in the range of m is 5.0 to 9
It is preferable to contain 0.0% by mass. More preferably, the aluminum hydroxide powder has a particle size of 35 to 15
Aluminum hydroxide powder in the range of 0 μm
Hydroxide containing 5.0% to 90.0% by mass of aluminum hydroxide powder containing 90.0% by mass and having a particle size in the range of 10 to 35 μm, and having a particle size in the range of 0.5 to 10 μm. It is to use an aluminum hydroxide powder containing 1 to 90 mass% of aluminum powder.

As the aluminum hydroxide powder having a particle size distribution in a desired range, aluminum hydroxide powder having various particle size distributions may be mixed and used. For example, the aluminum hydroxide powder is 5.0 to 90.0 mass% of the aluminum hydroxide powder having an average particle size in the range of 35 to 150 μm.
Further, aluminum hydroxide powder obtained by mixing 5.0 to 90.0 mass% of aluminum hydroxide powder having an average particle diameter in the range of 10 to 35 μm can be used. It is more effective to use aluminum hydroxide powder in which 1 to 90% by mass of aluminum hydroxide powder in the range of 0.5 to 10 μm is mixed. Of course, it is also possible to mix and use the aluminum hydroxide powder mixed as described above with the aluminum hydroxide powder having another distribution. These aluminum hydroxide powders may be mixed with other aluminum hydroxide powders in any order as long as the specified amount of aluminum hydroxide having the above average particle diameter is mixed.

The particle size distribution of the aluminum hydroxide powder before mixing used in the present invention is not particularly limited as long as it has the particle size distribution of the aluminum hydroxide powder that is usually obtained, but it is converted into volume. 90% cumulative average diameter (D90)
Ratio of 10% cumulative average diameter (D10) in terms of volume, D9
It is preferable that 0 / D10 is 1.5 to 30.

The aluminum hydroxide powder used in the present invention is more effective when a mixture of aluminum hydroxide powders having different BET specific surface areas and average particle diameters is used as described below.

That is, the BET specific surface area is 1.0 m ² /
5.0 to 90.0 mass% of aluminum hydroxide powder having an average particle size of 35 to 150 μm and a BET specific surface area of 2.0 m ² / g or less and an average particle size of It is preferable to mix 5.0 to 90.0 mass% of aluminum hydroxide powder in the range of 10 to 35 μm. Further, 30.0 to 80.0 mass% of aluminum hydroxide powder having a BET specific surface area of 1.0 m ² / g or less and an average particle diameter of 35 to 150 μm, BET
It is more preferable to mix 5.0 to 70.0 mass% of aluminum hydroxide powder having a specific surface area of 2.0 m ² / g or less and an average particle diameter of 10 to 35 μm.
As a more preferable example, the BET specific surface area is 1.0 m ² /
50.0 to 80.0% by mass of aluminum hydroxide powder having an average particle diameter of 35 g or less and an average particle diameter of 35 to 150 μm, a BET specific surface area of 2.0 m ² / g or less, and an average particle diameter of This is the case where 5.0 to 50.0 mass% of aluminum hydroxide powder in the range of 10 to 35 μm is mixed.

It is also possible to mix the following aluminum hydroxide powder. That is, the BET specific surface area is 1.0 m ² / g or less, and the average particle size thereof is 35 to 35.
Aluminum hydroxide powder in the range of 150 μm
0-90.0 mass%, BET specific surface area 2.0 m ² / g
5.0-90.0 mass% of aluminum hydroxide powder having the following average particle diameter in the range of 10-35 μm,
An aluminum hydroxide powder obtained by mixing 5.0 to 90.0 mass% of aluminum hydroxide powder having a BET specific surface area of 3.0 m ² / g or less and an average particle diameter of 0.5 to 10 μm. It is preferable to use them as a mixture. As a more preferable example, 30.0 to 80.0 mass% of aluminum hydroxide powder having a BET specific surface area of 1.0 m ² / g or less and an average particle diameter of 35 to 150 μm, and a BET specific surface area of Of 2.0 m ² / g or less and 5.0 to 70.0 mass% of aluminum hydroxide powder having an average particle size of 10 to 35 μm and a BET specific surface area of 3.0 m ² / g or less. Yes The average particle size is 0.5-1
Aluminum hydroxide powder in the range of 0 μm
70.0 mass% is mixed and used. As a particularly preferable example, 50.0 to 80.0 mass% of aluminum hydroxide powder having a BET specific surface area of 1.0 m ² / g or less and an average particle diameter of 35 to 150 μm, and a BET specific surface area of Is 2.0 m ² / g or less and the average particle size is 1
5.0 to 50.0% by mass of aluminum hydroxide powder having a BET specific surface area of 3.0 m ²
/ G or less and the average particle diameter thereof is in the range of 0.5 to 10 μm, and 5.0 to 30.0 mass% of aluminum hydroxide powder is mixed and used.

In this case as well, in addition to the two types of aluminum hydroxide powder and the three types of aluminum hydroxide powder, aluminum hydroxide powder having a different BET specific surface area and particle size distribution may be mixed and used. You can mix them in any order.

The BET specific surface area depends substantially on the average particle size and the degree of coagulation of the aluminum hydroxide powder. If the average particle size and the degree of coagulation are large, the compatibility with the resin becomes poor and it becomes difficult to highly fill the powder. Also, if the content of aluminum hydroxide powder is the same, it is possible to lower the viscosity during kneading by making the particle size distribution wider, and as a result, it becomes easier to fill highly, so mixing multiple aluminum hydroxides as described above. It is effective to use it.

The aluminum hydroxide powder used in the present invention has a BET specific surface area of S and a particle size Dbet calculated by sphere approximation (where Dbet is Dbet = 6 / (S × ρ)). Ρ is the specific gravity of aluminum hydroxide) and the average particle diameter D ratio (cohesion degree) D / Dbet is preferably less than 3. A cohesion degree (D / Dbet) of less than 3 means that the aluminum hydroxide powder has a relatively rounded shape, and the closer the powder shape is to a sphere, the viscosity at the time of kneading. Can be lowered, and as a result, high filling can be facilitated. It is preferable that all or part of the aluminum hydroxide powder contained in the heat conductive composition of the present invention has an aggregation degree of less than 3.

Regarding the BET specific surface area, there are a volume method, a weight method, a flow method, etc. as a method for detecting the adsorption amount of nitrogen gas.
The values shown in the present invention are values measured by a simple flow method with relatively high accuracy. The amount of sample used at this time is usually 10 g or less, though it depends on the surface area.

As the average particle diameter D, a value measured by a laser scattering diffraction method is used. The average particle diameter is usually measured by dispersing aluminum hydroxide in water. At this time, if it is not possible to disperse, a surfactant may be used, and if necessary,
It may be dispersed by a homogenizer or ultrasonic waves. The concentration of the aluminum hydroxide powder to be dispersed is usually 1% or less. As the laser, a semiconductor laser having a wavelength of 780 nm was used.

The method for adjusting the particle size distribution of the aluminum hydroxide powder of the present invention has already been described, but it can be obtained by mixing a plurality of aluminum hydroxide powders having different average particle sizes because the production conditions are different. You can also The method of mixing is not particularly limited, but a Henschel mixer or the like can be used.

In addition, the aluminum hydroxide powder of the present invention may be appropriately pretreated. For example, an aluminum hydroxide powder surface-modified by pretreatment with a silane coupling agent, a titanate coupling agent, stearic acid or the like may be used.

The plasticizer is added as a softening agent to adjust the flexibility of the heat conductive composition, and known materials can be used without particular limitation, and examples thereof include silicone oil, synthetic oil, fluorine oil, Mineral oil (petroleum-based oil) or synthetic oil can be used. Examples of preferable oils include paraffin-based oils, naphthene-based oils, and aromatic oils. Particularly preferable examples include paraffinic and naphthenic types. Aromatic oils may adversely affect cold resistance and durability. Of these, paraffinic oils are particularly preferable, and among paraffinic oils, those having less aromatic ring components are particularly suitable.
Further, the hydro-modified oil has characteristics such as high durability and resistance to alteration, and is suitable as a plasticizer used in the present invention.

The plasticizer has a flash point of 170-300.
Those having a temperature of 100 ° C. and a weight average molecular weight of 100 to 5000 are preferable. The content in the thermally conductive composition is 1 to 20% by mass.
Is preferred. If it exceeds 20% by mass, bleeding out of the plasticizer is likely to occur and mechanical properties are likely to deteriorate. Further, if the content is less than 1% by mass, the flexibility required for the obtained composition cannot be obtained.

The tackifier used in the present invention is added to fix the electronic device, the semiconductor device or the display device and the heat dissipation device when used in the form of a sheet. The tackifier that can be used in the present invention is not particularly limited, and conventionally known ones can be used. For example, rosin-based resins (gum rosin, tall oil rosin, wood rosin, modified rosin-based resins (hydrogenated rosin, disproportionated rosin, polymerized rosin, maleated rosin, etc.), rosin ester-based (rosin glycerin ester, hydrogenated rosin / glycerin Ester, rosin / pentaerythritol ester, hydrogenated rosin / pentaerythritol ester, perhydrogenated rosin / glycerin ester, stabilized rosin / pentaerythritol ester, etc.), petroleum resin (hydrocarbon (aliphatic petroleum, aromatic) Group petroleum-based, dicyclopentadiene-based, heat-reactive, aromatic modified aliphatic petroleum-based, etc.), aliphatic petroleum resin (C5 type), aromatic petroleum resin (C9 type), copolymer petroleum resin (C5 / C9 type), alicyclic petroleum resin (hydrogenation type, dicyclopentadiene type, etc.), terpene type resin (α
-Pinene, β-pinene, d-limonene, aromatic modified, phenol modified terpene, polyterpene, hydrogenated terpene, etc.), pure monomer resin (styrene / α-methylstyrene, α-methylstyrene / vinyltoluene, styrene, etc.) (Meth) acrylic), coumarone / indene resin,
Examples include phenolic resins and xylene resins. These may be used alone or in combination of two or more.

Particularly preferred examples are rosin resins (rosin resins, modified rosin resins), terpene resins (terpene resins), petroleum resins (petroleum resins, aliphatic petroleum resins, aromatic petroleum resins, copolymers). Petroleum resin, alicyclic petroleum resin)
Is mentioned. The content in the heat conductive composition is not particularly limited and may be added depending on the target adhesive force, but is preferably 1 to 20 mass%. If it exceeds 20% by mass, mechanical properties tend to deteriorate. Also, the content is 1
If it is less than mass%, the tackiness required for the obtained composition cannot be obtained.

Although the thermoplastic elastomer is an elastic body such as rubber, it is characterized in that it can be molded in the same manner as the thermoplastic resin, is recyclable, and has physical properties such as hardness and elasticity. Thermoplastic elastomer has a flexible component (soft segment, soft phase) having rubber elasticity in the molecule and a molecular restraint component (hard segment, hard phase) for preventing plastic deformation, and the hard phase is plasticized by heating. Soften. The thermoplastic elastomer may be modified by adding a plasticizer, a tackifier, a cross-linking agent, a filler, or an antioxidant, and they are all kneaded, that is, a thermally conductive composition The softening temperature or melting temperature is preferably 200 ° C. or lower. When it exceeds 200 ° C, decomposition of aluminum hydroxide begins to release water. A more preferable thermoplastic elastomer has a softening temperature or melting temperature of 180 ° C.
It is the following.

The thermoplastic elastomer used in the present invention is not particularly limited and known ones can be used.
Styrene type, polyester type, polyurethane type, olefin type and the like are preferable. Examples of styrene elastomers are SBS (styrene-butadiene-styrene block copolymer), SIS (styrene-isoprene-styrene block copolymer), SEBS (styrene-ethylene-butadiene-styrene block copolymer), SEP.
Examples thereof include S (styrene-ethylene-propylene-styrene block copolymer).

Examples of the polyester type include polybutylene terephthalate-polytetramethylene glycol polymer and polybutylene terephthalate-polycaprolactone polymer. The former is called polyether ester elastomer and the latter is called polyester ester elastomer. .

As the polyurethane type, diisocyanate (4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated 4,4-diphenylmethane diisocyanate, etc.) and short-chain glycol (ethylene glycol) are used. , Hard phase consisting of propylene glycol, 1,4-butanediol, bisphenol A, etc., diisocyanate and long chain polyol (polyalkylene glycol such as polytetramethylene glycol, polyalkylene adipate, polycaprolactane, polycarbonate etc.) And a polymer having a soft phase composed of

The olefin type includes a blend type and a cross-linking (polymerization) type. The former is mainly polypropylene and ethylene-propylene copolymer, or ethylene-
Examples thereof include propylene-diene copolymer. As the diene at this time, ethylidene norbornene, 1,4-hexadiene, dicyclopentadiene and the like are used.
In addition to simple blends, partially crosslinked with organic peroxides, completely crosslinked rubber phase dispersed at the time of kneading, further polyethylene blended with hard phase resin, NBR (acrylonitrile-butadiene) as rubber Examples thereof include a blend of a copolymer rubber) and a styrene block copolymer.

The number average molecular weight of these thermoplastic elastomers is preferably in the range of 5,000 to 1,500,00, and the molecular structure may be linear, branched, radial or any combination thereof. Further, these thermoplastic elastomers can be used alone or by kneading two or more kinds.

Examples of preferable thermoplastic elastomers include styrene type because of their heat resistance and flexibility.

The content of the thermoplastic elastomer is 1
-20 mass% is preferable.

The thermally conductive composition of the present invention is highly filled with aluminum hydroxide powder, has thermal conductivity, and has a thermal conductivity of 0.5 W / m · K or more. preferable. When it is 0.5 W / m · K or less, heat radiating and soaking action from the heating element is reduced.

The kneading method for obtaining the heat conductive composition of the present invention is not particularly limited, and a known method can be used. For example, a blade type kneading machine (kneader etc.), a roll type kneading machine (roll mill, taper roll, pressure kneader, Banbury mixer, internal mixer, Labo Plastomill, mix lab, extruder, etc.) can be mentioned, but a roll mill is preferable. And extruders.

The heat conductive composition of the present invention can be processed into a sheet having a thickness of 0.1 to 3 mm depending on the application. The processing method is not particularly limited, and extrusion processing, compression molding, calender molding and the like can be performed, but extrusion molding and calender molding that can be continuously molded and can be wound are preferable. At this time, if the adhesiveness is strong, polytetrafluoroethylene sheet or release paper,
It is preferable to process while using a release film or the like to prevent dust from adhering to the molding device. The sheet-shaped thermally conductive composition can be wound into a roll with a release paper and a release film sandwiched therebetween. The size of the sheet is not particularly limited and can be processed according to the application. A more preferable manufacturing method is a method in which each component is kneaded by an extruder and extruded into a T-die to form a sheet, and the sheet is wound together with a double-sided release paper or a double-sided release film by a sheet take-up device. The extrusion conditions at this time differ depending on the composition or the width of the sheet to be formed, but the set temperature of the extruder is 1
30 ~ 190 ℃, screw rotation speed 5 ~ 80rpm, L
/ D (screw length to diameter ratio) is preferably 20 or more.

The heat conductive sheet of the present invention is UL94.
Standards (Underwriters Laboratori
es Inc. It is preferable that one of the standards No. 94) is satisfied. UL94 standard is a standard for flammability testing of plastic materials for equipment and instrument parts,
Meeting this standard is classified as a material with high flame retardancy. Since the thermally conductive composition of the present invention is used for electric appliances and the like, flame retardancy is important. 20 for aluminum hydroxide
Since it decomposes at 0 ° C. or higher to release water, the composition containing the aluminum hydroxide powder can impart flame retardancy. The composition of the present invention has a UL9 content when processed into 1 mm sheets.
4 standards (5V, V-0, V-1, V-2, H
It is a composition having flame retardancy satisfying B) and excellent flexibility.

The heat conductive sheet of the present invention preferably has an Asker C hardness of 70 or less. Asker C is J
It is defined in IS K 7312 or SRIS 0101. If it is hard, the adhesion will be poor, it will not be possible to follow the irregularities on the surface, it will become brittle, and it will be difficult to wind it into a roll.

If necessary, an antioxidant, a cross-linking agent, a thermoplastic resin, a filler other than aluminum hydroxide, a flame retardant other than aluminum hydroxide, etc. may be added to the heat conductive composition of the present invention. . Examples of the antioxidant include aldehydes, amines, phenols and the like. Examples of the cross-linking agent include organic peroxides, epoxies, isocyanates, di (meth) acrylates and the like. Examples of the thermoplastic resin include polyethylene, polypropylene, (meth) acrylic resin, polystyrene and the like. Examples of the filler include carbon black, carbon fiber, graphite fine powder, glass fiber, aluminum oxide, boron nitride, silicon carbide, boron carbide, aluminum nitride, zinc oxide, aluminum, copper, magnesium hydroxide and the like. Examples of the flame retardant include nitrogen-based flame retardants (such as triazine-based), PPE (polyphenylene ether), silicone-based flame retardants, aromatic carboxylic acids and their metal salts, boron compounds, and zinc compounds.

These heat conductive sheets efficiently radiate heat generated by being sandwiched between a heat generating portion of an electronic component or a semiconductor device and a heat radiating component or a heat radiating plate, and the electronic component, the semiconductor device or the display. It is possible to reduce heat deterioration of the device, reduce failures, and extend the life. The specific electronic components or semiconductor devices are not particularly limited, but include a CPU (central processing unit) of a computer and a PDP.
(Plasma display panel), organic EL device, secondary battery or peripheral equipment thereof (in a hybrid electric vehicle or the like, a thermally conductive composition is provided between the secondary battery and a radiator to control the temperature and stabilize the battery characteristics. Device), a radiator of a motor, a Peltier device, an inverter, a (high) power transistor, and the like.

Particularly, in the plasma display panel, the heat generated by the discharge and the large panel tend to cause nonuniform heat. Therefore, a structure for radiating and soaking is necessary. The plasma display panel has a relatively large area, and a temperature difference within the panel is likely to occur depending on the color and brightness of light emitted. If this temperature difference is large, there is a risk of breaking the glass panel. Therefore, soaking is also necessary to eliminate this temperature difference. Since the heat conductive sheet of the present invention has heat conductivity and adhesiveness, it is optimal for sticking a panel and a heat sink. Since the plasma display panel is a glass panel, it is difficult to process it.To attach an aluminum heat sink, in general, attach the aluminum heat sink to the back of the panel via an adhesive sheet. Is being done. Further, the panel and the heat dissipation plate are not completely flat and have slight irregularities, so that the heat conductive sheet is required to have flexibility in order to enhance adhesion. The heat conductive sheet is excellent in tackiness, flexibility, adhesion, flame retardancy and durability in addition to heat conductivity, and is optimal as a heat conductive sheet for a plasma display panel. A plasma display panel using the heat conductive sheet is obtained by, for example, attaching the heat conductive sheet to a panel (glass panel or the like) and further attaching a heat dissipation plate (aluminum chassis or the like). Alternatively, it is possible to first attach the heat conductive sheet to the heat dissipation plate and then attach the panel. The sticking method is not particularly limited, and examples thereof include a method of automatically sticking a roll-shaped heat conductive sheet by a machine or the like.

[0078]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

The following components were used as each component. Thermoplastic Elastomer: Riken Technos Co., Ltd. Super Soft Actimer AE-2000S (Styrenic Thermoplastic Elastomer Resin)

Aluminum hydroxide: Mixing ratios shown in Table 1 were used.

[0081]

[Table 1]

Plasticizer: Diana Process Oil PW-90 (olefin process oil) manufactured by Idemitsu Kosan Co., Ltd.

Tackifier: Yasuhara Chemical Co., Ltd. Clearon P105 (hydrogenated terpene resin)

<BET Specific Surface Area> Measured with Multisorb-12 manufactured by Yuasa Ionics Co., Ltd.

<Average particle size> HRA (X- manufactured by Nikkiso Co., Ltd.)
100).

<Kneading> Labo Plastomill (Toyo Seiki E
The model) was used for kneading at 170 ° C. for 5 minutes.

<Sheet Forming> A 1 mm-thick stainless steel plate was punched out into a mold, the kneaded composition was put therein, and both sides were sandwiched with aluminum foil, and further, both sides were sandwiched with a 3 mm stainless steel plate. Preheat it with a press machine that heated it to 180 ° C.
Min, pressurization 1 min, and cooling pressurization 5 min.

<Softening temperature> Sample piece 5 × 5 mm, thickness 1 m
It was cut into m pieces and sandwiched between 5φ × 1 mm thick alumina sintered bodies. Using RMA-8310 manufactured by Rigaku Denki, a weight of 10 g was applied to the probe to raise the temperature at 5 ° C./min. A tangent line was drawn from the obtained temperature-thickness variation curve graph to determine the intersection point as the softening temperature.

<Flame Retardancy> Measured in accordance with UL94 standard. The thickness of the test piece was 1.0 mm.

<Asker C Hardness> Asker C hardness was measured according to SRIS 0101.

<Thermal Conductivity> ASTM (American)
Society for Testing and
Thermal resistance was measured according to Materials D5470. The thickness of the test piece was 1 mm.

<Shear Adhesion Test> 50 × 125 mm, thickness 1.5 mm aluminum plate and 50 × 125 mm, thickness 1.
A 25 × 25 mm, 1 mm thick heat conductive sheet was adhered between 5 mm glass plates such that the unadhered portions of the aluminum plate and the glass plate were in opposite directions. 5kg on the pasted part
The force of f was applied for 15 minutes and pressure was applied. 30 in tensile tester
It was pulled at a speed of 0 mm / min and the maximum force until peeling was measured. The value was divided by the area of the heat conductive sheet to obtain shear adhesive strength.

Thermally conductive sheets were prepared with the formulations shown in Table 2 for Examples 1 and 2 and Comparative Examples 1 to 5, and the softening temperature,
The flame retardancy, Asker C hardness, thermal conductivity, and shear adhesive strength were measured. The results are shown in Table 2.

[0094]

[Table 2]

[0095]

The heat conductive composition of the present invention has excellent flexibility, adhesion and heat conductivity, and can achieve flame retardancy without using a conventional halogen-based or phosphorus-based flame retardant. It was Further, by producing an electronic component, a semiconductor device or a display device in which the composition of the present invention is provided between a heat generating element and a heat radiating element, a high performance capable of withstanding a higher speed operation and a higher load as compared with a conventional one. It is possible to configure the device of (1) and is most suitable for a plasma display panel.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/36 H01L 23/36 D (72) Inventor Nobuo Uotani 1-1-1 Onodai, Midori-ku, Chiba-shi, Chiba No. 1 Showa Denko KK R & D Center (72) Inventor Akira Onishi 8 Ebisu-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Showa Denko Co., Ltd. AF023 BA013 BP011 CF101 CK021 DE146 FD022 FD203 FD206 GQ00 GQ05 5F036 BA23 BB21 BC05 BC23 BD21

Claims (31)

[Claims] 1. A thermally conductive composition comprising aluminum hydroxide powder, a plasticizer, a tackifier and a thermoplastic elastomer. 2. The content of aluminum hydroxide powder is in the range of 70% by mass to 85% by mass with respect to the total amount of aluminum hydroxide, a plasticizer, a tackifier and a thermoplastic elastomer. The heat conductive composition according to claim 1. 3. The heat conductive composition according to claim 1, wherein the aluminum hydroxide powder has an oil absorption of linseed oil of 20 ml / 100 g or less. 4. The aluminum hydroxide powder has a particle size of 0.
The heat conductive composition according to any one of claims 1 to 3, wherein the aluminum hydroxide powder having a range of 5 to 150 µm is contained in an amount of 70% by mass or more of the aluminum hydroxide powder. 5. The aluminum hydroxide powder has a particle size of 35.
Aluminum hydroxide powder in the range of ˜150 μm is contained in an amount of 5.0 to 90.0% by mass of the aluminum hydroxide powder, and aluminum hydroxide powder in the range of particle size is in the range of 10 to 35 μm. 5.0-90.
The heat conductive composition according to claim 4, which is an aluminum hydroxide powder containing 0% by mass. 6. The aluminum hydroxide powder has a particle size of 35.
Aluminum hydroxide powder in the range of ˜150 μm is contained in an amount of 5.0 to 90.0% by mass of the aluminum hydroxide powder, and aluminum hydroxide powder in the range of particle size is in the range of 10 to 35 μm. 5.0-90.
An aluminum hydroxide powder containing 0 mass% of aluminum hydroxide powder having a particle diameter in the range of 0.5 to 10 μm in an amount of 1 to 90 mass% of the aluminum hydroxide powder. Item 5. The heat conductive composition according to item 4. 7. An aluminum hydroxide powder having an average particle diameter in the range of 35 to 150 μm is 5.0 to 90.0% by mass of the aluminum hydroxide powder and has an average particle diameter of 10. Aluminum hydroxide powder in the range of ~ 35 μm is
The heat conductive composition according to claim 4 or 5, which contains an aluminum hydroxide powder mixed with 0.0% by mass. 8. An aluminum hydroxide powder having an average particle diameter in the range of 35 to 150 μm is 5.0 to 90.0% by mass of the aluminum hydroxide powder,
The aluminum hydroxide powder having an average particle diameter in the range of 10 to 35 μm is the aluminum hydroxide powder of 5.0 to 90.
An aluminum hydroxide powder containing 0% by mass and an aluminum hydroxide powder having an average particle diameter in the range of 0.5 to 10 μm mixed in an amount of 1 to 90% by mass of the aluminum hydroxide powder is contained. Item 7. A heat conductive composition according to Item 4 or 6. 9. The aluminum hydroxide powder has a BET specific surface area of 1.0 m ² / g or less and an average particle diameter of 35 to 35.
The aluminum hydroxide powder in the range of 150 μm is added to 5.0 to 90.0% by mass of the aluminum hydroxide powder and B
Aluminum hydroxide powder having an ET specific surface area of 2.0 m ² / g or less and an average particle diameter of 10 to 35 μm is 5.0 to 90.0% by mass of the aluminum hydroxide powder.
The heat conductive composition according to claim 4 or 5, comprising mixed aluminum hydroxide powder. 10. The aluminum hydroxide powder has a BET specific surface area of 1.0 m ² / g or less and an average particle diameter of 35.
Aluminum hydroxide powder in the range of ˜150 μm is 5.0 to 90.0% by mass of aluminum hydroxide powder, BE
An aluminum hydroxide powder having a T specific surface area of 2.0 m ² / g or less and an average particle diameter of 10 to 35 μm is added to 5.0 to 90.0 mass% of the aluminum hydroxide powder and the BET specific surface area. Is 3.0 m ² / g or less and the average particle diameter of the aluminum hydroxide powder is in the range of 0.5 to 10 μm is 1 to 90% by mass of the aluminum hydroxide powder.
The heat conductive composition according to claim 4 or 6, comprising mixed aluminum hydroxide powder. 11. A particle diameter D calculated by spherical approximation, where S is the BET specific surface area of all or part of the aluminum hydroxide powder.
bet (here, Dbet is calculated by Dbet = 6 / (S × ρ). ρ is the specific gravity of aluminum hydroxide) and the average particle diameter D (cohesion degree) D / Dbet is less than 3. It exists, The heat conductive composition in any one of Claims 1-10 characterized by the above-mentioned. 12. The plasticizer is a paraffinic oil and / or a naphthenic oil.
The heat conductive composition according to any one of 1 to 11. 13. The heat conductive composition according to claim 1, wherein the content of the plasticizer is 1 to 20% by mass of the composition. 14. The tackifier is rosin-based, terpene-based,
14. At least one tackifier selected from the petroleum series, which is characterized in that
The thermally conductive composition according to any one of 1. 15. The composition according to claim 1, wherein the content of the tackifier is 1-2.
The heat conductive composition according to any one of claims 1 to 14, which is in a range of 0% by mass. 16. The thermoplastic elastomer is a styrene type,
The heat conductive composition according to any one of claims 1 to 15, which is at least one elastomer selected from the group consisting of polyester, polyurethane and olefin. 17. The softening temperature or melting temperature of the thermally conductive plastic material is 200 ° C. or lower.
16. The heat conductive composition according to any one of 16. 18. The thermally conductive composition according to claim 1, wherein the content of the thermoplastic elastomer is in the range of 1 to 20% by mass of the composition. 19. The thermally conductive composition according to claim 1, which has a thermal conductivity of 0.5 W / m · K or more. 20. The method according to claim 1, wherein kneading is performed.
9. The method for producing the heat conductive composition according to any one of 9 above. 21. A heat conductive sheet comprising the heat conductive composition according to any one of claims 1 to 19. 22. The thickness of the heat conductive composition is 0.1 to 3 mm.
22. The heat conductive sheet according to claim 21, wherein the heat conductive sheet is in the form of a sheet. 23. The heat conductive sheet according to claim 21, wherein the heat conductive sheet when processed to have a thickness of 1 mm satisfies any of UL94 standards. 24. The heat conductive sheet according to claim 21, wherein the hardness according to Asker C is 70 or less. 25. A method for producing a heat conductive sheet, characterized in that the heat conductive composition according to any one of claims 1 to 19 is formed into a sheet having a size of 0.3 to 1 mm. 26. An electronic component in which the heat conductive sheet according to any one of claims 21 to 24 is provided between a heat generating body and a heat radiating body. 27. A semiconductor device in which the heat conductive sheet according to any one of claims 21 to 24 is provided between a heat generating body and a heat radiating body. 28. A display device in which the heat conductive sheet according to claim 21 is provided between a heat generating body and a heat radiating body. 29. A plasma display panel using the heat conductive sheet according to claim 21. 30. Dissipation and / or soaking of an electronic component, a semiconductor device, a display device or a plasma display panel, characterized by using the thermally conductive composition according to claim 1. Method. 31. An electronic component, characterized by using the heat conductive sheet according to claim 21.
A method for radiating and / or soaking a semiconductor device, a display device or a plasma display panel.