TW201831602A - Thermally conductive resin composition, heat dissipation sheet, heat dissipation member and method for producing same - Google Patents

Abstract

The present invention provides a thermally conductive resin composition which enables the achievement of a resin molded body that has high thermal conductivity and high flexibility. A thermally conductive resin composition which contains the components (A)-(D) described below and provides a resin molded body that has an Asker C hardness of 30 or less. (A) a two-liquid addition reaction type liquid silicone which contains an organopolysiloxane that has a vinyl group at least at an end or in a side chain and an organopolysiloxane that has two or more H-Si groups at least at an end or in a side chain, and which has a viscosity at 25 DEG C of 100 to 2,500 mPa.s (B) 1-20% by volume of a high molecular weight silicone that has two or more vinyl groups at least at an end or in a side chain (C) 0.05-2% by volume of an alkyl alkoxy silane (D) 63-85% by volume of an inorganic filler.

Description

   Thermally conductive resin composition, radiating fin, radiating member and manufacturing method thereof   

The present invention relates to a thermally conductive resin composition, a resin molded body, a heat sink, a heat sink member, and a method of manufacturing the same.

With the miniaturization and high output of electronic parts, the heat per unit area generated from those electronic parts becomes very large. The increase in temperature may cause the life of electronic parts to decrease, malfunction, or malfunction. Therefore, a heat sink or frame made of metal is used for cooling the electronic parts, and a heat conductive material is used to further efficiently transfer heat from the electronic parts to the cooling part such as the heat sink or the frame. As a reason for using this thermally conductive material, when electronic parts are directly in contact with heat sinks or the like, if viewed closely, air is present at the interface, which becomes an obstacle to thermal conduction. Thereby, the thermally conductive material is present between the electronic component and the heat sink, etc., to replace the air present at the interface, so that the heat can be efficiently transferred.

As the thermally conductive material, there are those obtained by filling the resin with thermally conductive powder. Examples of the resin include silicone resins, acrylic resins, and epoxy resins. From the viewpoint of good balance between heat resistance and flexibility, silicone resins are often used.

Examples of thermally conductive materials using silicone resins include thermally conductive sheets filled with thermally conductive fillers in silicone rubber or silicone gel, or thermally conductive pastes filled with thermally conductive fillers in silicone oil. The adhesion between the paste system and the interface is higher than that of the sheet, and it can be thinned to the maximum particle size of the thermally conductive filler, so that low thermal resistance can be achieved. However, since it is liquid, there is a disadvantage of causing dripping or overflow. On the other hand, the sheet system has excellent workability compared to the paste, and can be compressed and fixed between the electronic component and the heat sink or the frame, and the dripping or overflowing property like the paste is good. However, the sheet is solid and compressed for use, so the compressive stress is large. Therefore, the use of the sheet may be one of the causes of failure of electronic parts or distortion of the frame.

Since it is necessary to transfer the heat of the heating element on the substrate to dissipate the heat to the cooling frame, Patent Document 1 and Patent Document 2 propose heat sinks.

Specifically, claim 8 of Patent Document 1 describes a heat sink having a thermal conductivity of 5.4 W / mK or more and an Asker C hardness of 60 or less, which is produced using a highly thermally conductive resin composition The high thermal conductivity resin composition is formed by using a high thermal conductivity resin compound containing 60 to 90 vol% of blended particles in volume ratio. The blended particles are included according to the following blend: 60 ~ 80 vol% spherical alumina particles with an average particle size of 50-100 μm, 5-30 vol% spherical alumina particles with an average particle size of 0.5-7 μm, and 10-35 vol% aspheric particles with an average particle size of 0.5-7 μm Bauxite particles.

In addition, claim 6 of Patent Document 2 describes a resin molded body having a thermal conductivity of 5.0 W / mK or more and a sheet hardness of 60 or less, which contains more than 72% by volume to 80% by volume in the resin % Bauxite blended particles, wherein the bauxite blended particles have a particle size distribution in the range of more than 30 μm to 100 μm, more than 5 μm to 30 μm, and less than 5 μm, respectively, including 60 to 85% by volume. Bauxite particles in the range of 30 μm to 100 μm, alumina particles with a particle size distribution of 5 to 15% by volume in the range of more than 5 μm to 30 μm or less, and alumina particles with a particle size distribution of 10 to 25% by volume in the range of 5 μm or less Particles, the alumina particles having a particle size distribution in the range of more than 30 μm to 100 μm are spherical particles, and the alumina particles having a particle size distribution in the range of 30 μm or less are non-spherical particles.

Prior technical literature Patent Literature

Patent Literature 1 Japanese Patent Application Publication No. 2007-277406

Patent Document 2 Japanese Patent Laid-Open No. 2009-274929

Furthermore, in Patent Document 1, in fact, as a heat sink with a low sheet hardness (10 mm), it is described that it is possible to produce a heat sink having an Asker C hardness of 45, a thermal conductivity of 5.4 W / mK, and an alumina filling rate of 59% by volume A sheet (Inventive Example 30) and a heat sink having an Asker C hardness of 42 and a thermal conductivity of 5.3 W / mK and an alumina filling rate of 77% by volume (Comparative Example 16).

In addition, Patent Document 2 actually describes that as a heat sink with a low sheet hardness (2.5 mm), it is possible to produce an Asker C hardness of 48, a thermal conductivity of 5.2 W / mK, and an alumina filling rate of 72.5 vol% A heat sink (Example 46) and a heat sink with an Asker C hardness of 39, a thermal conductivity of 4.6 W / mK, and an alumina filling rate of 71.4% by volume (Comparative Example 45).

At present, when a heat-radiating fin with high thermal conductivity is obtained, an inorganic filler may be highly filled in the resin composition, but the high filling of the inorganic filler impairs the flexibility of the heat-radiating fin. Therefore, in Patent Literature 1 and Patent Literature 2, the Asker C hardness of the heat sink can only be made to 39. Despite this, the current situation is that such Asker C hardness fins still do not achieve the required flexibility.

Specifically, if a heat-dissipating fin with high thermal conductivity is currently obtained, the flexibility of the fin is deteriorated. Therefore, there is a large stress on the substrate when the fin is sandwiched, and the mounted component is peeled off due to the bending of the substrate, or the heat dissipation There is a concern that the component exerts an inappropriate force.

In addition, if the filling rate of the inorganic filler is suppressed in order to impart flexibility to the radiating fin, naturally the thermal conductivity of the radiating fin decreases, which cannot satisfy the required heat dissipation characteristics.

Therefore, it is currently impossible to provide a heat sink capable of satisfying both high thermal conductivity and high flexibility.

That is, the main object of the present invention is to provide a thermally conductive resin composition capable of obtaining a resin molded body having high thermal conductivity and high flexibility.

Therefore, the inventors conducted a keen review in order to solve the above-mentioned problems, and as a result, they found that it is possible to provide an organic polysiloxane containing a vinyl group and an organic group having an H-Si group that can be used in combination: component (A) Polysiloxane, two-component addition silicone with specific viscosity; (B) high molecular weight silicone with vinyl; and (C) alkyl alkoxysilane to obtain highly inorganic fillers and high thermal conductivity A thermally conductive resin composition with a highly flexible resin molded body. Thus, the inventors found that the following means can be used to achieve the objective.

That is, the present invention is composed of the following.

[1] A thermally conductive resin composition comprising the following components (A) to (D), the hardness of the resin molded body being 30 or less in terms of Asker C.

(A) An organic polysiloxane containing at least a vinyl group at the terminal or side chain, and an organic polysiloxane having at least two H-Si groups at the terminal or side chain, and the viscosity at 25 ° C is 100 ~ 2,500mPa. s two-component addition reaction type liquid silicone

(B) 1 to 20% by volume of high molecular weight silicone having at least two vinyl groups at the terminal or side chain

(C) Alkylalkoxysilane 0.05 ~ 2% by volume

(D) Inorganic filler 63 ~ 85% by volume

[2] The thermally conductive resin composition according to [1], wherein the organic polysiloxane having a vinyl group at least at the terminal or side chain of the aforementioned component (A) and at least two or more at the terminal or side chain The ratio of H-Si-based organic polysiloxane is 1: 1.5 ~ 1.5: 1.

[3] The thermally conductive resin composition according to [1] or [2], wherein the particle size distribution of the inorganic filler has a maximum value or a peak in the range of average particle diameters of 10 to 100 μm, 1 to 10 μm, and less than 1 μm, average The inorganic filler system with a particle size of 10 to 100 μm is 23 to 50% by volume, the inorganic filler system with an average particle size of 1 to 10 μm is 15 to 30% by volume, and the inorganic filler system with an average particle size of less than 1.0 μm is 5 to 20% by volume.

[4] A resin molded body composed of the thermally conductive resin composition according to any one of [1] to [3].

[5] A heat sink using the thermally conductive resin composition according to any one of [1] to [3].

[6] A heat sink or a highly thermally conductive heat dissipation member for a communication member, which uses the thermally conductive resin composition as described in any one of [1] to [3], having a thermal conductivity of 3 W / mK or more and Asker The C hardness is 30 or less.

[7] A method for producing the thermally conductive resin composition according to any one of [1] to [3].

According to the present invention, it is possible to provide a thermally conductive resin composition capable of obtaining a resin molded body having high thermal conductivity and high flexibility, and also to provide a resin molded body having high thermal conductivity and high flexibility.

Forms for carrying out the invention

Hereinafter, suitable embodiments for implementing the present invention will be described. However, the present invention is not limited to the following embodiments, and can be freely changed within the scope of the present invention. The scope of the present invention should not be interpreted narrowly.

    <Thermally conductive resin composition of the present invention>    

The resin composition of the present invention contains: component (A) contains (a1) an organic polysiloxane having a vinyl group at least at the terminal or side chain, and (a2) has at least two H at the terminal or side chain -Si-based organic polysiloxane, viscosity at 25 ℃ is 100 ~ 2,500mPa. s two-component addition reaction type liquid silicone; component (B) high molecular weight silicone with vinyl groups at both ends 1-20% by volume; component (C) alkylalkoxysilane 0.05-2% by volume; component (D) 63 to 85% by volume of the inorganic filler; in terms of Asker C, the hardness of the resin molded body becomes a thermally conductive resin composition having a hardness of 30 or less.

In the resin composition of the present invention, the component (a1) and the component (a2) in the component (A) react with the four components of the component (B) and the component (C) to harden to form silicone rubber. Therefore, by using the components (A) to (C), even if the resin composition has a high content of 63 to 85% by volume of the inorganic filler, a highly flexible resin molded body can be obtained.

In addition, since the inorganic filler can be highly contained, a resin molded body with high thermal conductivity can be obtained.

<Component (A) two-component addition reaction type liquid silicone>

The component (A) two-component addition reaction type liquid silicone of the present invention contains the component (a1) organic polysiloxane having a vinyl group at least at the terminal or side chain (hereinafter, also referred to as "organic group having a vinyl group Polysiloxane ”), and component (a2) an organic polysiloxane having at least two H-Si groups at the terminal or side chain (hereinafter, also referred to as“ organic polysilicon having H-Si group ” Oxane ".). For the aforementioned component (A), it is desirable that the viscosity at 25 ° C is 100 to 2,500 mPa. s. Further, in terms of the degree of suitability, it is desirable that the ratio of (a1) to (a2) is between 1: 1.5 and 1.5: 1.

The aforementioned component (a1) is an organic polysiloxane having a vinyl group at least at either the terminal or side chain, and may have either a linear structure or a branched structure. Generally speaking, a part of the R part of the intramolecular (Si-R) of the organopolysiloxane-based organopolysiloxane having a vinyl group becomes a vinyl group (for example, refer to the following general formula (a1-1) ~ (a1-4)).

The vinyl content is preferably 0.01 to 15 mol% in the component (a1), and more preferably 0.01 to 5 mol% in the component (a1).

The organopolysiloxane having a vinyl group of the aforementioned component (a1) is suitably an alkyl polysiloxane having a vinyl group. The alkyl group preferably has 1 to 3 carbon atoms (for example, methyl, ethyl, etc.), more preferably methyl.

In addition, the organopolysiloxane having a vinyl group of component (a1) is preferably one having a mass average molecular weight of less than 400,000, more preferably 10,000 to 200,000, and still more preferably 15,000 to 200,000.

Here, the "vinyl content" of the present invention refers to the mole% of vinyl group-containing siloxane units when all the units of the constituent component (a1) are set to 100 mole%. However, for one vinyl group-containing siloxane unit, one vinyl group is set.

    <Measurement method of vinyl content>    

The vinyl content was determined by NMR. Specifically, using ECP-300 NMR manufactured by JEOL, the sample was dissolved in deuterated chloroform as a heavy solvent to perform measurement. The ratio of vinyl groups when (vinyl group + H-Si group + Si-methyl group) is set to 100 mol% is defined as vinyl content mol%.

The aforementioned component (a2) is an organic polysiloxane having at least two H-Si groups at any one of the terminal or side chain, and may have either a linear structure or a branched structure. Generally speaking, a part of the R part in the molecule (Si-R) of the organopolysiloxane-based organopolysiloxane having an H-Si group becomes an H group (for example, refer to the following general formula (a2-1 ) ~ (a2-4)).

The content of this H-Si group is preferably 0.01 to 15 mol% in (a2), and more preferably 0.01 to 5 mol% in component (a2).

The organic polysiloxane of the aforementioned component (a2) is suitably an alkyl polysiloxane having an H-Si group. The alkyl group preferably has 1 to 3 carbon atoms (for example, methyl, ethyl, etc.), more preferably methyl.

In addition, the organic polysiloxane having H-Si group of component (a2) is preferably one having a mass average molecular weight of 400,000 or less, more preferably 10,000 to 200,000, and even more preferably 15,000 to 200,000.

Here, the "content of H-Si group" of the present invention refers to the mole% of the H-Si group-containing siloxane unit when all the units of the component (a2) are set to 100 mole%.

    <Measurement method of H-Si content>    

The H-Si group content was measured by NMR. Using ECP-300NMR manufactured by JEOL, the sample was dissolved in deuterated chloroform as a heavy solvent for measurement. When (vinyl + H-Si group + Si-methyl) is set to 100 mol%, the ratio of H-Si groups contained is set to the content of H-Si groups in mol%.

The viscosity of the above-mentioned component (A) two-liquid addition reaction type liquid silicone system at 25 ° C is 100-2,500 mPa. s, preferably 100 ~ 2,000mPa. s, preferably 350 ~ 2,000mPa. s.

If the viscosity (25 ℃) of the aforementioned component (A) is less than 100mPa. s, the molecular weight is small, so the hardened sheet may easily crack, if it exceeds 2,500mPa. s, it may become difficult to highly fill the inorganic filler.

    <Measurement of viscosity>    

The viscosity of the two-component addition silicone was measured using a B-type viscometer "RVDVIT" manufactured by BROOKFIELD. The spindle uses an f-bar and can be measured using a viscosity of 20 rpm.

In addition, regarding the two-component addition reaction type liquid silicone of the aforementioned component (A), the aforementioned (a1) organopolysiloxane having a vinyl group and the aforementioned (a2) organopolysiloxane having an H-Si group The ratio is between 1: 1.5 ~ 1.5: 1, preferably 1: 1.4 ~ 1.4: 1, preferably 1: 1 ~ 1.4: 1, which is suitable for improving the flexibility.

In addition, the above-mentioned component (A) two-liquid addition reaction type liquid silicone is preferably an organic polysiloxane with internal thermosetting, in addition to the main component polyorganopolysiloxane polymer, hardening can also be used Agent (crosslinking organic polysiloxane).

The base polymer constituting the two-component addition reaction type liquid silicone is preferably one having an organic group (for example, methyl, phenyl, trifluoropropyl, etc.) in the main chain. For example, examples of the repeating structure of the organic polysiloxane include dimethylsiloxane units, phenylmethylsiloxane, and diphenylsiloxane units. In addition, modified organic polysiloxanes having functional groups such as vinyl groups, epoxy groups, and the like can be used.

In addition, the aforementioned two-component addition reaction type liquid silicone of the component (A) can use an addition reaction catalyst for accelerating the addition reaction.

In addition, the two-component addition reaction type liquid silicone of the aforementioned component (A) may be any commercially available product satisfying the above-mentioned various conditions.

The vinyl group at the terminal or side chain of the component (a1) can be exemplified by the following general formula (a1-1) and general formula (a1-2). In addition, the component (a1) has an organic polysiloxane having a vinyl group at least at the terminal or side chain, for example, those represented by general formula (a1-3) and general formula (a1-4) can be given. However, the present invention is not limited to these general formulas (a1-1) to (a1-4). In addition, the component (a1) of the present invention includes, for example, methyl polysiloxane having a vinyl group at the terminal and / or side chain.

The H-Si group at the terminal or side chain of the component (a2) can be exemplified by the following general formula (a2-1) and general formula (a2-2). The component (a2) has at least two H-Si groups at the terminal or side chain of the organic polysiloxane, for example, the following general formula (a2-3) and general formula (a2-4 ) Said. However, the present invention is not limited to these general formulas (a2-1) to (a2-4). In addition, the component (a2) of the present invention includes, for example, methyl polysiloxane having two or more H-Si groups at the terminal and / or side chain.

Examples of commercially available two-component addition reaction type liquid silicone rubbers include, for example, "X14-B8530" manufactured by Momentive, "SE-1885A / B" manufactured by Toray-Dow Corning, and Shin-Etsu Chemical. "KE-1283" manufactured by an industrial company, etc., but the present invention is not limited to the scope of these specific commercially available products.

The content of the two-component addition reaction type liquid silicone of the aforementioned component (A) is preferably 10 to 35% by volume, and more preferably 16 to 34% by volume. The content of the component (A), as the lower limit, is more preferably 12% by volume or more, and still more preferably 18% by volume or more. In addition, the content of the component (A), as the upper limit, is more preferably 33% by volume or less. If the content of the aforementioned component (A) is less than 10% by volume in the composition, the flexibility may be impaired, and if it exceeds 35% by volume in the composition, the thermal conductivity may decrease.

In addition, the addition reaction type liquid silicone used in the present invention can also be used with reaction retarders such as acetyl alcohols, maleates, aerogels or silicone powders of ten to hundreds of μm, etc. The tackifier, flame retardant, pigment, etc. are used together.

<Component (B) high molecular weight silicone having two or more vinyl groups in either terminal or side chain>

The high-molecular-weight silicone having component (B) of the present invention having two or more vinyl groups at either the terminal or side chain preferably has a mass average molecular weight of 400,000 to 900,000.

In the aforementioned component (B), the vinyl content is not particularly limited, in order to make it suitable for forming a network with each component in the composition, for example, in component (B), it is preferably 0.01 to 15 mol%, More preferably, it is 0.05 to 5 mol%.

Here, the "vinyl content" of the present invention refers to the mole% of vinyl group-containing siloxane units when all the units of the constituent component (B) are set to 100 mole%. The method for measuring the vinyl content is as follows.

    <Measurement method of vinyl content>    

The vinyl content was determined by NMR. Specifically, using ECP-300 NMR manufactured by JEOL, the sample was dissolved in deuterated chloroform as a heavy solvent for measurement. The ratio of vinyl groups when (vinyl + H-Si group + Si-methyl) is set to 100 mol% is defined as vinyl content mol%.

The component (B) of the present invention is preferably a silicone having a linear alkyl group containing a vinyl group, which is a vinyl group having a linear structure and a crosslinking point at the time of hardening. It is suitable to be expressed by the following general formula (B).

In the aforementioned formula (B), R ¹ and R ² are each independently substituted or unsubstituted alkyl, alkenyl, aryl, or a hydrocarbon group having a combination of 1 to 10 carbon atoms, among the plurality of R ¹ and R ² At least one or more is vinyl. A plurality of R ¹ systems are independent of each other, and may be different from each other or the same.

Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group. Among them, a methyl group is preferred.

Examples of the alkenyl group having 1 to 10 carbon atoms include vinyl, allyl, and butenyl, among which vinyl is preferred.

Examples of the aryl group having 1 to 10 carbon atoms include phenyl and the like.

In the aforementioned formula (B), R ³ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group combining them. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, and a propyl group. Among them, a methyl group is preferred. Examples of the aryl group having 1 to 8 carbon atoms include phenyl and the like. Among R ³ , a methyl group is preferred.

In the aforementioned formula (B), plural R ³ systems are independent of each other, and may be mutually different or the same.

M and n in the aforementioned formula (B) are the number of repeating units constituting the aforementioned component (B), m is an integer of 1000 to 10000, and n is an integer of 0 to 1000. m is preferably an integer of 3000 to 10000, more preferably an integer of 3600 to 8000. n is preferably an integer of 1 to 1000, more preferably an integer of 40 to 700.

As the aforementioned component (B), for example, it is preferable to have a structure represented by the following general formula (B1). In the following general formula (B1), R ¹ and R ² are each independently a methyl group or a vinyl group, and at least one of the plurality of R ¹ and R ² is a vinyl group.

In the following general formula (B1), R ^{1 is} suitably a methyl group, and R ^{2 is} suitably a vinyl group.

As the aforementioned component (B), commercially available products can be used, and examples thereof include TSE201 manufactured by Momentive Corporation, XE25-511 manufactured by Momentive Corporation, and SRH-32 manufactured by Momentive Corporation. TSE201 manufactured by Momentive Corporation is represented by the following formula (B1-1), for example.

Momentive's TSE-201 (trade name) series vinyl content: 0.2 mol%, mass average molecular weight 800,000, Momentive's SRH-32 (trade name) series vinyl content: 0.1 mol%, mass average molecular weight 500,000.

The content of the aforementioned component (B) is 1 to 20% by volume in the composition, and if it is 1% by volume or less, the moldability is deteriorated. The content of the aforementioned component (B) in the composition is preferably 2 to 15% by volume, and more preferably 4 to 10% by volume.

<Component (C) alkylalkoxysilane>

The component (C) alkylalkoxysilane of the present invention is not particularly limited, and may have a substituent. Commercially available products can be suitably used, for example, Z-6210 manufactured by Toray-Dow Corning Co., Ltd. and the like. Z-6210 (trade name) manufactured by Toray-Dow Corning is n-decyl trimethoxysilane.

The alkylalkoxysilane of the aforementioned component (C) is preferably a molecular weight of 100 to 300.

The aforementioned component (C) is preferably an alkylalkoxysilane having an alkyl group having 1 to 18 carbon atoms.

In addition, the alkyl group of the "alkylalkoxysilane" may be any of linear, branched, and cyclic.

In addition, the alkoxy group of "alkylalkoxysilane" can be used regardless of whether it is methoxy, ethoxy, or phenoxy.

The aforementioned component (C) is more preferably represented by the following general formula (C).

R ⁴ (R ⁵ ) _p SiX _3-p  (C)

In the above formula (C), R ⁴ is a linear or branched alkyl group having 1 to 18 carbon atoms, R ⁵ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X is 1 to 12 carbon atoms. Alkoxy, p is an integer of 0 ~ 2.

In the aforementioned formula (C), the carbon number of the alkyl group of R ⁴ is preferably 1-12, more preferably 1-10, even more preferably 6-10, still more preferably 8-10. R ^{4 is} preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, lauryl or the like. Among them, decyl is effective from the viewpoint of being difficult to volatilize.

In the aforementioned formula (C), R ^{5 is} preferably a methyl group.

In the aforementioned formula (C), p is preferably 0, so "X ₃ " is preferable.

In the aforementioned formula (C), X is preferably an alkoxy group having 1 to 6 carbon atoms, and for example, methoxy, ethoxy, n-propoxy, isopropoxy, phenoxy, etc. are preferred. Among them, the methoxy group is effective in terms of affinity with the filler.

In the aforementioned formula (C), "X _3-n " is preferably trimethoxy.

As the aforementioned alkylalkoxysilane, from the viewpoint of being difficult to volatilize, n-decyltrimethoxysilane is preferred.

The content of the alkylalkoxysilane in the component (C) of the present invention is 0.05 to 2% by volume in the composition, preferably 0.1 to 2% by volume. If it is less than 0.05% by volume, the affinity between the filler and the silicone will decrease and the thermal characteristics will be easily damaged. If it exceeds 2% by volume, the viscosity will drop sharply and the filler will easily precipitate.

<Component (D) inorganic filler>

The content of the thermally conductive filler in the resin composition of the present invention is preferably 63% by volume or more of the total volume, more preferably 65 to 85% by volume, and particularly preferably 70 to 85% by volume.

When the content of the thermally conductive filler is less than 63% by volume, the thermal conductivity of the sheet in which the resin composition is cured tends to be insufficient, so the higher the content, the more desirable. In addition, if it exceeds 85% by volume, the fluidity of the resin composition deteriorates, and the production of the cured product of the resin composition having a thickness of less than 0.3 mm easily becomes difficult, so it is preferably 85% by volume or less.

Examples of the inorganic filler used in the present invention include thermally conductive fillers such as aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum metal, and graphite. These can be used individually or in combination of 2 or more types. The inorganic filler used in the present invention is preferably spherical (the sphericity is suitably 0.85 or more).

Among them, alumina exhibits high thermal conductivity, and at the same time, it has good filling properties to resins, and is therefore ideal.

The alumina used in the present invention is preferably spherical. Alumina (hereinafter also referred to as "alumina") may be flame spraying method using aluminum hydroxide powder, Bayer method, ammonium alum thermal decomposition method, organoaluminum hydrolysis method, aluminum water discharge method, freeze drying method, etc. The manufacturer of any method is suitable for the flame spraying method of aluminum hydroxide powder from the viewpoint of controlling the particle size distribution and controlling the particle shape.

In addition, the crystal structure of the spherical alumina powder may be either a single crystal or a polycrystal. From the viewpoint of high thermal conductivity, the crystalline phase is preferably the α phase, and the specific gravity is preferably 3.7 or more. If the specific gravity is less than 3.7, the proportion of voids and low crystal phases present inside the particles increases, so it becomes difficult to increase the thermal conductivity to 2.5 W / mK or more. The particle size of the spherical alumina powder can be adjusted by the classification of the spherical alumina powder. Mixed operation.

When spherical alumina powder is used, the sphericity is 0.85 or more. When the sphericity is less than 0.85, the fluidity decreases and the filler segregates in the spacer, and the variation in physical properties becomes larger. Examples of commercially available products having a sphericity of 0.85 or more include spherical alumina DAW70 (trade name), spherical alumina DAW45S (trade name), spherical alumina DAW05 (product) manufactured by Denka Corporation. Name), spherical alumina ASFP20 (trade name), etc.

The particle size distribution of the inorganic filler of the present invention is preferably one having a maximum value or a peak in the range of average particle diameters of 10 to 100 μm, 1 to 10 μm, and less than 1 μm.

Among the inorganic filler-based inorganic fillers having an average particle diameter of 10 to 100 μm, preferably 23% by volume or more, more preferably 25 to 50% by volume, even more preferably 30 to 48% by volume, even more preferably 34 to 47% by volume %.

In addition, the inorganic filler-based inorganic filler having an average particle diameter of 1 to 10 μm is preferably 15 to 30% by volume, more preferably 20 to 28% by volume, and even more preferably 20 to 25% by volume.

In addition, the inorganic filler-based inorganic filler having an average particle diameter of less than 1.0 μm is preferably 5 to 20% by volume, more preferably 10 to 15% by volume, and even more preferably 11 to 13% by volume.

The particle size distribution of the aforementioned inorganic filler is preferably a combination of inorganic fillers in these three ranges.

The particle size distribution of the inorganic filler of the present invention is preferably an inorganic filler with an average particle diameter of 10 to 100 μm of 25 to 50% by volume (more preferably 34 to 47% by volume), and an inorganic filler with an average particle size of 1 to 10 μm of 15 to 30 Vol% (more preferably 20-25 vol%), inorganic filler with an average particle size of less than 1.0 μm is 5-20 vol% (more preferably 11-13 vol%).

<Manufacturing method of resin composition, resin molded body, heat sink, etc.>

The highly thermally conductive resin molded body of the present invention can be obtained by a known manufacturing method. For example, it can be obtained by mixing the aforementioned components (A) to (D).

In addition, the highly thermally conductive resin molded article of the present invention can be mixed with raw materials, for example. Forming. Add sulfur step to make it. In terms of mixing, a mixer such as a roll mill, a kneader, a Banbury mixer, or the like can be used. The forming method is preferably a doctor blade method, and an extrusion method can be used depending on the viscosity of the resin. Suppression method. Calender roll method, etc. The ideal vulcanization temperature is 50 ~ 200 ℃, and the heating and curing time is preferably 2 ~ 14 hours. When the temperature is less than 50 ° C, sulfur addition is insufficient, and if it exceeds 200 ° C, part of the spacer deteriorates. The vulcanization system is carried out using a general hot air dryer, far infrared dryer, microwave dryer, etc. It is possible to operate in this manner to obtain a thermally conductive resin molded body. As the resin raw material used in the present invention, in addition to the above-mentioned components (A) to (C), resin raw materials such as acrylic resin and epoxy resin can be appropriately selected within a range that does not impair the effects of the present invention. In addition, the composition of the present invention may be blended so as to be 100% by volume, or may be further added to the composition of the present invention at 100% by volume.

The thickness of the resin molded body obtained from the resin composition of the present invention is 0.3 mm to 6 mm, and particularly preferably 0.5 to 5 mm. If the thickness of the resin molded body is thinner than 0.3 mm, the surface roughness caused by the thermally conductive filler becomes large, and the thermal conductivity becomes poor. In addition, if it exceeds 6 mm, the cured product of the resin molded body becomes thick, and the thermal conductivity becomes poor. The thickness of the resin molded body is preferably based on the thickness of the resin composition after curing.

As described above, the thermally conductive resin composition system of the present invention can obtain a resin composition of a resin molded body having high thermal conductivity and high flexibility.

By using the resin composition of the present invention, a resin molded body and a heat sink having high thermal conductivity and high flexibility can be provided.

The resin molding system of the present invention has high thermal conductivity, and can provide a thermal conductivity of 3 W / mK or more, or even 5 W / mK or more.

In addition, the resin molding system of the present invention has high thermal conductivity and has an Asker C hardness of 30 or less. The Asker C hardness of the resin molded body is preferably 30 or less, more preferably 5 to 30, and even more preferably 7 to 15. If the Asker C hardness is less than 5, there is a possibility that the handling when processing the sheet becomes difficult.

In addition, the compression rate of the resin molded body of the present invention is preferably 25% or more, more preferably 30% or more, and still more preferably 35% or more.

The conventional high-thermal-conductivity resin molded body, as described above, can be manufactured with substantially Asker C hardness of about 40. Nevertheless, if the Asker C hardness exceeds 30, the thermally conductive sheet itself becomes hard, the adhesion to the heating element is impaired, and the thermal conductivity is deteriorated. However, by using the resin composition of the present invention, it is possible to have high conductivity with a thermal conductivity of 3 W / mK or more, and to set the Asker C hardness to 30 or less, so that a novel highly thermally conductive resin molded body can be provided.

In addition, the resin molded body of the present invention has high flexibility, and thus can have a compression ratio as high as 25% or more.

According to the present invention, it is possible to provide a resin molded body and a heat sink with high thermal conductivity and high flexibility. In addition, according to the present invention, it is possible to provide a heat dissipation material with a high thermal conductivity portion having high flexibility. In addition, a heat dissipation spacer can be suitably provided, which is particularly suitable as a heat dissipation member for electronic parts.

In addition, according to the present invention, it is possible to provide a mobile base station application, a battery application, and a power conditioner device using the high thermal conductivity heat dissipation member.

In addition, by using the resin composition of the present invention, it is possible to provide a heat-dissipating material with high thermal conductivity having high flexibility. The present invention is suitable as a heat dissipation member for electronic parts that requires adhesion of heat dissipation surfaces such as the heat generation surface of a semiconductor element and a heat radiation fin. The heat dissipation member of the present invention is preferably used as a heat dissipation fin, a heat dissipation spacer, or the like, for example.

In addition, by using the resin composition of the present invention, it is possible to provide wireless base station or mobile base station applications (for example, for communication, high-speed communication, etc.), storage battery applications, and power conditioners using the highly thermally conductive heat dissipation member Electronic parts required by devices, etc.

In addition, the heat dissipation member of the resin composition of the present invention is highly flexible and has excellent adhesion to heat dissipation elements, and can be applied to smart phones, tablet PCs, personal computers, home game consoles, power supplies, and automobiles as electronic devices For example, the use of wireless base stations.

For wireless base station applications, the power of heating elements increases with the increase in the specifications of high-speed communications. Therefore, it is necessary to increase the thermal conductivity required for heat dissipation materials, and gradually requires more than 2W / mK. Currently, 3 to 5 W / mK is required. If the thermal conductivity filler is highly filled in order to improve the thermal conductivity, the heat sink becomes hard, and there is a possibility of damage due to the warpage of the substrate or the stress of the heating element. This application requires high-flexibility heat dissipation materials, the Asker C hardness is less than 30, and the compression rate is required to be more than 25%.

According to the present invention, it is possible to provide a heat sink or a high thermal conductivity heat dissipation member used in electronic parts used in applications such as wireless base station applications that satisfy the conditions of a thermal conductivity of 3 W / mK or more and an Asker C hardness of 30 or less. In addition, those satisfying the conditions of thermal conductivity of 3 W / mK or more, Asker C hardness of 30 or less, and compression rate of 25% or more may be provided.

Moreover, the spacer system of the present invention can be mixed by the raw materials. Forming. Add sulfur step to make it. In terms of mixing, a mixer such as a roll mill, a kneader, a Banbury mixer, or the like can be used. The molding method is preferably a doctor blade method, and the extrusion method can be used according to the viscosity of the resin composition. Suppression method. Calender roll method, etc. The ideal vulcanization temperature is 50 ~ 200 ℃. When the temperature is less than 50 ° C, sulfur addition is insufficient, and if it exceeds 200 ° C, part of the spacer deteriorates. The vulcanization system is carried out using a general hot air dryer, far infrared dryer, microwave dryer, etc. By operating in this way, a thermally conductive sheet is obtained.

The present invention is suitable for use as a thermally conductive member such as an industrial member, and particularly suitable for a highly flexible thermally conductive resin composition having a small compression stress during mounting, a thermally conductive resin molded body, and a heat dissipating member.

    [Example]    

Hereinafter, the present invention will be described in detail by test examples (including examples and comparative examples). In addition, the present invention is not limited to the following embodiments.

Two-component addition reaction type silicon containing (a1: organopolysiloxane with vinyl group) + (a2: organopolysiloxane with H-Si group) using component (A) shown below Ketone, component (B) high molecular weight silicone having a vinyl group, component (C) alkoxysilane, component (D) inorganic filler, based on the blending ratio and volume% ratio of each test example described in Tables 1 to 4 Mix. In addition, the total amount of component (A) to component (D) is set to 100% by volume.

Using the mixed resin composition, a sheet (resin molded body) was prepared to a predetermined thickness using a doctor blade (method), and heat-cured at 110 ° C. for 8 hours.

The evaluation results of each test example are shown in Tables 1 to 4.

With regard to Test Examples 1 to 5, Test Examples 11 to 20, and Test Examples 28 to 30, by using the components (A) to (D), it is possible to obtain good flexibility within the range of the sheet thickness of 0.3 to 6 mm. Thermal conductivity heat sink. In addition, the ratio of (a1) to component (a2) is between 1.4: 1 and 1: 1.4, and a thermally conductive heat dissipation sheet having good flexibility can be obtained.

Regarding Test Examples 1 to 8 and Test Example 25, by containing 1 to 20% by volume of component (B), a high molecular weight silicone having a vinyl group, a thermally conductive heat dissipation sheet having good flexibility can be obtained. In addition, at this time, within the range of 67 to 85% by volume of the inorganic filler, a thermally conductive heat dissipation sheet having good flexibility can be obtained.

Regarding Test Examples 9 to 10 and Test Examples 19 to 30, by containing 0.05 to 2.0% by volume of the component (C) alkoxysilane, a thermally conductive heat dissipation sheet having good flexibility can be obtained. In addition, the ratio of (a1) to component (a2) is between 1.4: 1 and 1: 1.4, and a thermally conductive heat dissipation sheet having good flexibility can be obtained.

In addition, regarding Test Examples 31 to 34, when the component (C) alkoxysilane is not contained, a thermally conductive heat dissipation sheet having good flexibility cannot be obtained.

Regarding Test Examples 1 to 20 and Test Examples 26 to 30, by using component (A) two-liquid addition reaction type silicone-based viscosity 350 to 2,000 mPa. Those with sec can obtain a thermally conductive heat dissipation sheet with good flexibility. At this time, the ratio of component (a1) to component (a2) was 1.4: 1. In addition, regarding Test Examples 35 to 36, the viscosity of the two-liquid addition reaction type silicone exceeds 3,000 mPa. In the case of sec, a thermally conductive heat dissipation sheet with good flexibility cannot be obtained.

With respect to Test Examples 21 to 30, when the particle size distribution of the inorganic filler has a maximum value or a peak in the range of average particle diameters of 10 to 100 μm, 1 to 10 μm, and less than 1 μm, thermal conductivity with good flexibility can be obtained Sexual heat sink.

In particular, when there is a maximum value or a peak in the range of average particle diameters of 60 to 100 μm, 1 to 10 μm, and less than 1 μm, a thermally conductive heat dissipation sheet having excellent flexibility can be obtained.

The raw materials used to manufacture the resin composition are as follows.

    [Component (A) two-component addition reaction type silicone]    

＊ 1) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group (vinyl content 0.8mol%): organic polysiloxane with H-Si group (H-Si content 1.0mol%) = (a1) 1.4: (a2) 1); X14-B8530 manufactured by Momentive; viscosity 350mPa. sec; The mass average molecular weight of each organic polysiloxane is 21,000.

* 1-2) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group (vinyl content 0.8mol%): organic polysiloxane with H-Si group (H-Si content 1.0mol %) = (a1) 1: (a2) 1); X14-B8530 made by Momentive; viscosity 350mPa. sec; The mass average molecular weight of each organic polysiloxane is 21,000.

＊ 1-3) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group (vinyl content 0.8mol%): organic polysiloxane with H-Si group (H-Si content 1.0mol %) = (a1) 1: (a2) 1.4); X14-B8530 made by Momentive; viscosity 350mPa. sec; The mass average molecular weight of each organic polysiloxane is 21,000.

＊ 2) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group (vinyl content 0.3mol%): organic polysiloxane with H-Si group (H-Si content 0.5mol%) = (a1) 1.4: (a2) 1); SE-1885 manufactured by Toray-Dow Corning; viscosity 440mPa. sec; The mass average molecular weight of each organic polysiloxane is 120,000.

＊ 2-2) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group (vinyl content 0.3mol%): organic polysiloxane with H-Si group (H-Si content 0.5mol %) = (a1) 1: (a2) 1); SE-1885 manufactured by Toray-Dow Corning; viscosity 430mPa. sec; The mass average molecular weight of each organic polysiloxane is 120,000.

* 2-3) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group (vinyl content 0.3mol%): organic polysiloxane with H-Si group (H-Si content 0.5mol %) = 1: 1.4); SE-1885 manufactured by Toray-Dow Corning; viscosity 420mPa. sec; The mass average molecular weight of each organic polysiloxane is 120,000.

* 2-4) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group (vinyl content 0.3mol%): organic polysiloxane with H-Si group (H-Si content 0.5mol %) = 1: 1.6); SE-1885 manufactured by Toray-Dow Corning; viscosity 400mPa. sec; The mass average molecular weight of each organic polysiloxane is 120,000.

* 3) Two-component addition reaction type silicone (organic polysiloxane with vinyl group: organic polysiloxane with H-Si group = (a1) 1.4: (a2) 1); Shin-Etsu Chemical Co., Ltd. KE-1283; viscosity 2,000mPa. sec.

＊ 4) Two-liquid addition reaction type silicone (organic polysiloxane with vinyl group: organic polysiloxane with H-Si group) = (a1) 1.4: (a2) 1; two made by Momentive Corporation Liquid addition molding silicone TSE-3331K (organic polysiloxane with vinyl: organic polysiloxane with H-Si group = 1.4: 1); viscosity 3,000mPa. sec.

* 5) High molecular weight silicone having vinyl groups at the terminal or side chain; SRH-32 manufactured by Momentive; vinyl content: 0.1 mol%, mass average molecular weight 500,000.

* 6) High-molecular-weight silicone having a vinyl group at the terminal or side chain; TSE-201 manufactured by Momentive; vinyl content: 0.2 mol%, mass average molecular weight 800,000.

* 7) Alkoxysilane; Z-6210 manufactured by Toray-Dow Corning; n-decyltrimethoxysilane.

[Component (D) inorganic filler]

The inorganic filler uses the following alumina. The volume% of the inorganic filler in the table is the total amount of each spherical filler and each crystalline alumina used.

Filler d50: 70 μm: spherical alumina DAW70 manufactured by Denka Corporation

Filler d50: 45 μm: spherical alumina DAW45S manufactured by Denka Corporation

Filler d50: 5 μm: spherical alumina DAW05 manufactured by Denka Corporation

Filler d50: 0.3 μm: spherical bauxite ASFP20 manufactured by Denka Corporation

In addition, the following crystalline alumina powder is used.

D50: 3 μm: crystalline alumina AA-3 manufactured by Sumitomo Chemical Co., Ltd.

D50: 0.5 μm: crystalline alumina AA-05 made by Sumitomo Chemical Co., Ltd.

[Evaluation criteria]

The evaluation system is judged as follows.

＊ The thermal conductivity is less than 3W / mK is not good, the thermal conductivity is 3W / mK or more is good, 5W / mK or more is excellent.

When the compression rate is less than 25%, it is not good, and when the compression rate is more than 25%, it is good.

When the Asker C hardness is greater than 30, the high flexibility is not good, when the Asker C hardness is 30 or less, the high flexibility is good, and when the Asker C hardness is 15 or less, the high flexibility is excellent.

<Thermal conductivity>

The sheet obtained above was cut into TO-3 type, and the thermal resistance was measured. Then, the thermal conductivity is calculated using the following equations (1) and (2).

The thermal conductivity is between the TO-3 type copper heater casing (effective area 6.0cm ² ) with the transistor built in and the copper plate, which is compressed to 10% of the initial thickness. After applying a load by means of a method and fixing it, apply 15W of power to the transistor and hold it for 5 minutes. Use the formula (2) to convert the temperature difference (℃) between the heater shell and the heat dissipation fin and use the formula (1) The thermal resistance (℃ / W).

Calculate using the formula of "Thermal resistance (℃ / W) = (heater side temperature (℃)-cooling side temperature (℃)) / power (W) ... (1)". Then, it can be calculated using the formula of "thermal conductivity (W / mK) = thickness (m) / (cross-sectional area (m ² ) x thermal resistance (° C / W)) ... (2)".

<Ask C hardness>

The hardness of the silicone resin used in the present invention after hardening can be measured with an Asker C type spring-type hardness according to SRIS0101 at 25 ° C. Asker C hardness can be measured with "Asker Rubber Hardness Tester Type C" manufactured by Macrometer Co., Ltd. After the silicone resin is hardened, Type C Asker C hardness is 5 ~ 30, ideally 7 ~ 15. If the type C hardness is less than 5, the workability when processing the sheet becomes difficult.

In addition, if it exceeds 30, the thermally conductive sheet itself becomes hard, the adhesion to the heating element is impaired, and the thermal conductivity is deteriorated.

<Compression rate>

The compression ratio used in the present invention is to measure the compressive deformation when a load of 0.1 MPa is applied in the thickness direction with a table test machine (EZ-LX manufactured by Shimadzu Corporation) after punching the spacer into 10 × 10 mm Amount, with compression ratio (%) = {compression deformation amount (mm) × 100} / original thickness (mm)

Calculate the compression ratio.

<Mass average molecular weight>

The mass average molecular weight of the polyorganosiloxane and silicone is defined as the value converted from polystyrene calculated from the results of gel permeation chromatography analysis. The separation system is a non-aqueous porous gel (polystyrene-dimethylbenzene copolymer), toluene is used as the mobile phase, and the detection system uses a differential refractometer (RI).

<Average particle size, maximum particle size, maximum value>

The average particle size, maximum particle size, and maximum value of the inorganic filler are measured using "laser diffraction particle size distribution measuring device SALD-200" manufactured by Shimadzu Corporation. In the evaluation sample, 50 cc of pure water and 5 g of the measured inorganic filler powder were added to a glass beaker, stirred with a spatula, and then subjected to a dispersion treatment with an ultrasonic cleaner for 10 minutes. Using a pipette, a solution of the powder of the inorganic filler subjected to dispersion treatment was added dropwise to the sampling portion of the device, and waited for stability until the absorbance can be measured. Operate in this way, and measure when the absorbance becomes stable. The laser diffraction type particle size distribution measuring device calculates the particle size distribution from the data based on the light intensity distribution of the diffraction / scattered light of the particles detected by the sensor. The average particle size is obtained by multiplying the relative particle amount (difference%) by the measured particle size and dividing by the total relative particle amount (100%). In addition, the average diameter of the average particle diameter-based particles can be obtained as the maximum value or the cumulative weight average D ₅₀ (or median diameter) of the peak value. In addition, the particle size at which the D ₅₀ series has the highest occurrence rate.

Claims (7)

    A thermally conductive resin composition comprising the following components (A) to (D), the hardness of the resin molded body is 30 or less in terms of ASKER C, (A) includes at least the terminal or side chain Vinyl-based organic polysiloxanes, and organic polysiloxanes having at least two H-Si groups at the ends or side chains, the viscosity at 25 ° C is 100 to 2,500 mPa. s two-component addition reaction type liquid silicone; (B) high molecular weight silicone with at least two vinyl groups at the terminal or side chain 1-20% by volume; (C) alkyl alkoxy silicone 0.05 ~ 2% by volume; (D) 63 ~ 85% by volume of inorganic filler.         The thermally conductive resin composition according to claim 1, wherein in the component (A), an organic polysiloxane having a vinyl group at least at the terminal or side chain, and H-Si having at least two or more at the terminal or side chain The ratio of organic polysiloxane based group is 1: 1.5 ~ 1.5: 1.         The thermally conductive resin composition according to claim 1 or 2, wherein the particle size distribution of the inorganic filler has a maximum value or a peak in the range of average particle diameters of 10 to 100 μm, 1 to 10 μm, and less than 1 μm, and an average particle diameter of 10 to 100 μm The inorganic filler is 23 to 50% by volume, the average particle size is 1 to 10, the inorganic filler is 15 to 30% by volume, and the inorganic filler is 5 to 20% by volume with an average particle size of less than 1.0 μm.         A resin molded body composed of the thermally conductive resin composition according to any one of claims 1 to 3.         A heat sink using the thermally conductive resin composition according to any one of claims 1 to 3.         A heat sink or a high thermal conductivity heat dissipation member for a communication member, which uses the heat conductive resin composition according to any one of claims 1 to 3, having a thermal conductivity of 3 W / mK or more and an Asker C hardness of 30 or less .         A method for producing a thermally conductive resin composition according to any one of claims 1 to 3.