JP2011074340A - Thermally conductive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermally conductive composition keeping stable syringe discharge property at normal temperatures, quickly cured in a comparatively low temperature environment, and thereby capable of preventing liquid dripping, bleed contamination and the like at service places. <P>SOLUTION: There is provided a one-pack type thermally conductive composition comprising an organic polymer liquid at normal temperatures and a thermally conductive filler, cured within a temperature range of 60-150°C while keeping practically liquid or pasty state at normal temperatures, and having 15-100 Shore A hardness after the curing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermally conductive composition, and in particular, maintains a stable syringe discharge property at room temperature, and quickly cures in a relatively low temperature environment. The present invention relates to a thermally conductive composition that can prevent bleed contamination and the like.

  An optical pickup such as a DVD includes a laser light source, a lens, a light receiving unit, and the like for recording and reproducing data. When manufacturing an optical pickup part, it is necessary to fix the various optical elements on a support, and generally, a plurality of point bonds using an adhesive in units of several tens of mg are employed. For this reason, it is necessary for the adhesive to be stably discharged from the syringe for a long time. Conventionally, a grease type or a room temperature moisture curing type is used (see, for example, Patent Documents 1 and 2). Further, since heat is generated at the optical pickup portion during use, it is preferable that the adhesive also has a function as a heat conducting agent in order to efficiently remove the heat.

  However, the grease type adhesive is basically an uncured type, and there is a problem that sagging occurs when the temperature rises. In addition, room temperature moisture-curing adhesives generally have a very slow cure to ensure good syringe discharge properties, causing problems such as chemical contamination such as bleed of components and clouding of the lens. There was a point.

JP 2002-363429 A JP 2002-36312 A

  Therefore, the object of the present invention is to maintain a stable syringe discharge property at room temperature, and to cure quickly in a relatively low temperature environment, thereby preventing liquid dripping and bleed contamination at the point of use. An object of the present invention is to provide a heat conductive composition useful as an adhesive and a heat conductive agent in an optical pickup portion.

The present invention is as follows.
1. Contains an organic polymer and a thermally conductive filler that are liquid at room temperature, cures in a temperature range of 60 ° C. to 150 ° C. while maintaining a substantially liquid or paste shape at room temperature, and 15 to 100 shores after the curing. A one-component heat conductive composition characterized by having A hardness.
2. The above 1 is characterized in that the organic polymer is an organic polymer having an acid anhydride group and an average molecular weight of 1000 or more, and the thermally conductive composition further contains a thermal latent curing agent. The heat conductive composition as described.
3. 3. The thermally conductive composition as described in 2 above, wherein the thermal latent curing agent is at least one selected from an amine adduct type, an imidazole compound, a dicyandiamide, and a hydrazide compound.
4). The thermally conductive filler is made of at least one metal oxide selected from aluminum oxide, aluminum nitride, boron nitride and magnesium oxide, and the thermally conductive composition exhibits a resistance value of 10 ⁸ Ω or more. The heat conductive composition according to any one of claims 1 to 3.
5). 5. The heat conductive composition as described in any one of 1 to 4 above, further comprising at least one selected from a dispersant, a surfactant, a plasticizer, a solvent, and an adhesion promoter.
6). 6. The heat conductive composition as described in any one of 1 to 5 above, which is used as an adhesive and a heat dissipation material in an electronic component.
7). 7. The thermally conductive composition as described in 6 above, wherein the electronic component is a recording or reproducing optical pickup part.

  The heat conductive composition of the present invention does not proceed with curing at room temperature or in the presence of moisture, and can maintain stable syringe discharge properties over a long period of time. Further, since it is liquid or pasty before curing, it can be easily repaired as necessary. Furthermore, since it cures quickly in a relatively low temperature environment, it is possible to prevent dripping or bleed contamination at the point of use. It is also very easy to cure only the surface of the composition and leave the interior uncured by adjusting the heating time for curing. Furthermore, after the whole is cured, it has a specific elasticity, so that it can be easily cut and removed with a knife or a cutter when further repair / maintenance is required. The heat conductive composition of the present invention is useful as an adhesive and a heat conductive agent in an optical pickup part such as a DVD.

  Hereinafter, the present invention will be described in more detail.

(Organic polymer)
The organic polymer used in the present invention is an organic polymer that is liquid at room temperature. The normal temperature in the present invention usually means 5 ° C. to 35 ° C. (20 ° C. ± 15 ° C .: JIS Z8703 compliant).
The organic polymer used in the present invention is not particularly limited as long as it is cured in the temperature range of 60 ° C. to 150 ° C., preferably 70 ° C. to 100 ° C. in the presence or absence of a curing agent. From the viewpoint of the above effect, an organic polymer having an acid anhydride group is preferable, and specific examples thereof include polybutadiene having an acid anhydride group and diene rubbers such as polyisoprene. The organic polymer preferably has an average molecular weight of 1000 or more from the viewpoint of the effect of the present invention. A more preferable average molecular weight is 1000 to 100,000. In the present invention, the average molecular weight means the number average molecular weight measured by ASTM D2503 or the like.

In polybutadiene, polyisoprene and the like (hereinafter also referred to as “anhydride-modified polymer”) having an acid anhydride group as described above, the acid anhydride group has a structure obtained by dehydration condensation of two molecules of carboxylic acid (R -CO-O-CO-R), and the acid anhydride-modified polymer includes a carboxylic acid anhydride (eg, phthalic anhydride, maleic anhydride) in the main chain and / or side chain of the polymer. And acids formed by introducing an acid or the like directly or through an organic group. In the present specification, an organic polymer having a maleic anhydride group is sometimes referred to as a maleic anhydride-modified polymer.
Among these, polybutadiene or polyisoprene having a maleic anhydride group is preferable because it exhibits high reactivity with a thermal latent curing agent described later.
The method for introducing the acid anhydride group is not particularly limited, and the acid anhydride group can be introduced by an ene reaction between unsaturated double bonds.

  Moreover, it is preferable that the introduction rate (addition ratio) of the acid anhydride group in the acid anhydride-modified polymer is 0.5 to 10.0 (mol / mol).

  Commercially available products may be used as the acid anhydride-modified polymer in the present invention, and examples include PolyvesOC 800 (manufactured by Degussa) and LIR403 (manufactured by Kuraray, number average molecular weight 30000) used in the examples described later.

(Thermal conductive filler)
A well-known thing can be used for a heat conductive filler. For example, inorganic oxides such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide and silica, and nitrogen inorganic compounds such as aluminum nitride, boron nitride and silicon nitride Organic materials such as carbon, graphite and silicon carbide, and metal powders such as silver, copper and aluminum are preferably used. These can be used alone or in combination of two or more. Among them, in the present invention, aluminum oxide, aluminum nitride, boron nitride, magnesium oxide, and the like are preferable in terms of both thermal conductivity and insulation (resistance value).

  The heat conductive filler may have any shape such as a spherical shape, a powder shape, a fiber shape, a needle shape, and a scale shape, and the particle size is about 1 to 100 μm in average particle size.

(Thermal latent curing agent)
The composition of the present invention preferably uses a heat latent curing agent. Examples of the heat latent curing agent include amine adduct type; 2-heptadecylimidazole, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl-S-triazine, 2-phenyl-4 , 5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 1,3-dibenzyl-2-methylimidazolium chloride Dicyandiamide such as dicyandiamide or o-tolylbiguanide, α-2,5-dimethylbiguanide, α, ω-diphenylbiguanide, 5-hydroxynaphthyl-1-biguanide or derivatives thereof; succinic hydrazide, adipic hydrazide , Isophthalic acid hydrazide p- hydroxybenzoic acid hydrazide, salicylic acid hydrazide, hydrazide compounds such as phenyl-aminopropionic acid hydrazide; and the like.

(Mixing ratio)
In the heat conductive composition of the present invention, the blending ratio of the heat conductive filler is preferably 100 to 3000 parts by weight, and more preferably 300 to 2000 parts by weight with respect to 100 parts by weight of the organic polymer.
When using a heat latent hardener, 1-25 weight part is preferable with respect to 100 weight part of organic polymers, and 1-15 weight part is further more preferable.

The composition of the present invention can contain various additives as required in addition to the various components as long as the object of the present invention is not impaired. Examples of the additive include a dispersant, a plasticizer, a solvent, and an adhesion imparting agent.
Examples of the dispersant include those called surfactants, thickeners, wetting agents, anti-settling agents, anti-dripping agents, leveling agents, thixotropic agents, slip agents, antifoaming agents, antistatic agents, and the like. However, what is generally referred to as a surfactant is used for the purpose of wetting the particle surface in the process of crushing the particle aggregate.
For example, as low molecular weight dispersants, anionic fatty acid salts (soap), MES, ABS, LAS, AS, AES, alkylsulfuric triethanolamine, etc., nonionic fatty acid diethanolamide, AE (higher alcohol), APE, Alkyltrimethylammonium salts, dialkyldimethylammonium chlorides, alkylpyridinium chlorides are used as cationic systems, and alkylcarboxybetaines (betaines) are used as amphoteric systems. Polyacrylic acid moieties are used as non-aqueous dispersions for polymer dispersants. Examples thereof include alkyl esters and polyalkylene polyamines.
Examples of plasticizers include general plasticizers such as phthalic acid derivatives, mineral softeners such as process oils, rubber softeners such as plant softeners, extenders, and rubber processing aids. Etc.
Examples of the solvent include alcohols such as methanol, ethanol and isopropyl alcohol, hydrocarbons such as hexane, heptane and cyclohexane, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, methyl cellosolve and butyl cellosolve. Ethers such as are mainly used. Examples thereof include aromatic hydrocarbons such as toluene and xylene, and chlorinated solvents such as methylene chloride.
Examples of the adhesion imparting agent include terpene resins, phenol resins, terpene-phenol resins, rosin resins, xylene resins, and epoxy resins.
The aforementioned additives can be used in combination as appropriate.

  The method for producing the composition of the present invention containing each of these components is not particularly limited, but each of the above components is used under a reduced pressure or an inert gas atmosphere such as nitrogen using a stirring device such as a mixing mixer. A method of sufficiently kneading and uniformly dispersing is preferable. The composition of the present invention thus produced is substantially liquid or pasty at room temperature.

The composition of the present invention can be used as a one-component composition.
The composition of the present invention is cured in a temperature range of 60 ° C. to 150 ° C., preferably 70 ° C. to 100 ° C., and has a Shore A hardness of 15 to 100, preferably 20 to 80 after the curing. Here, the Shore A hardness referred to in the present invention is a value measured by a “durometer hardness test (type A)” defined in JIS K6253-1997. If the Shore A hardness is less than 15, residual tack may remain and may cause adhesion of dust. If the Shore A hardness exceeds 100, problems such as difficulty in removing at the time of repair after curing may occur. . The hardness can be adjusted by adjusting the blending ratio of the heat conductive filler.
The composition of the present invention preferably exhibits a resistance value of 10 ⁸ Ω or more as a resistance value, that is, basically is an insulating type.

  Since the composition of the present invention has high thermal conductivity and has both adhesive properties and heat dissipation properties, it is useful as an adhesive and heat dissipation material in electronic components. It is low-temperature curable, and can be prevented from dripping or bleeding contamination, and is useful as an adhesive for an optical element and a heat dissipating material in a recording or reproducing optical pickup part such as a DVD.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example.

Examples 1-4 and Comparative Examples 1-2
Various components shown in Table 1 below were uniformly stirred and mixed, and the composition of the present invention was prepared by crushing the filler aggregate and further defoaming. In addition, the mixture ratio shown in Table 1 is a mass part.

Details of various components in Table 1 are shown below.
Poly110: Polybutadiene manufactured by Evonik Degussa. Number average molecular weight = 2000. Liquid at room temperature.
Poly iP + y 5187: Polyisoprene having a hydroxyl group at Idemitsu Kosan Co., Ltd. Poly iP: 100 parts by weight of the number average molecular weight = 2500, Y-5187: 5 parts by weight of isocyanate silane made by Momentive Performance Materials, 80 parts mixed Silane-modified polyisoprene produced by addition reaction at 5 ° C for 5 hours. Liquid at room temperature.
PolyvestOC800S: Polybutadiene manufactured by Degussa. Maleic anhydride modified polymer. Number average molecular weight = 2400. Liquid at room temperature.
LIR403: Kuraray polybutadiene. Maleic anhydride modified polymer. Number average molecular weight = 30,000. Liquid at room temperature.
PS-32: Process oil manufactured by Idemitsu Kosan Co., Ltd.
Disparon 1761: Leveling agent manufactured by Enomoto Kasei Co., Ltd.
A174: Methacrylate silane manufactured by Momentive Performance Materials.
AS-40: Aluminum oxide manufactured by Showa Denko KK Particle size = 12μm
NO. 918: A tin catalyst manufactured by Sansha Co., Ltd.
PN40: a thermal latent curing agent manufactured by Ajinomoto Co., Inc.
Ancamine 2014FG: a thermal latent curing agent manufactured by Air Product.
EH-4357S: Thermal latent curing agent manufactured by ADEKA.

About each composition prepared as mentioned above, curability after 20 hours at 20 ° C. (20 ° C. and 12H curability), curability after 1 hour at 80 ° C. (80 ° C. and 2H curability), bleeding property The Shore hardness A was examined. The results are also shown in Table 1.
The bleed property was evaluated based on the length of the bleed portion after 24 hours by dropping 1.5 ml of the composition as a circle having a diameter of about 30 mm on a filter paper in an environment of 70 ° C. The bleed portion is the length in one direction of the bleed component leached in a circular shape from the suspended composition, and specifically, (the bleed portion of the bleed component spreading in a circular shape from the center point of the suspended composition). The length of the tip portion) − (the radius of the composition hung in a circle).

From the results of Table 1, the compositions of the present invention were all uncured after 12 hours at 20 ° C. This is because curing does not proceed at room temperature or in the presence of moisture, and stable syringe discharge can be maintained over a long period of time. Also, since it is liquid or pasty before curing, it can be easily repaired as needed. It shows that there is. Furthermore, from the results in Table 1, it was confirmed that the composition of the present invention hardened rapidly after 1 hour at 80 ° C. This indicates that the composition of the present invention cures rapidly in a relatively low temperature environment, and can prevent dripping and bleed contamination at the point of use. Furthermore, the composition of the present invention exhibits a Shore A hardness of 40 to 55 after curing, which can be easily cut off and removed with a knife or a cutter when further repair / maintenance is required. I found it possible.
On the other hand, the compositions of Comparative Examples 1 and 2 were not able to satisfy both curability, bleeding property and elasticity.

Claims (7)

  Contains an organic polymer and a thermally conductive filler that are liquid at room temperature, cures in a temperature range of 60 ° C. to 150 ° C. while maintaining a substantially liquid or paste shape at room temperature, and 15 to 100 shores after the curing. A one-component heat conductive composition characterized by having A hardness.   The organic polymer is an organic polymer having an acid anhydride group and an average molecular weight of 1000 or more, and the thermally conductive composition further contains a thermal latent curing agent. The heat conductive composition as described in any one of.   The heat conductive composition according to claim 2, wherein the heat latent curing agent is at least one selected from an amine adduct type, an imidazole compound, a dicyandiamide, and a hydrazide compound. The thermally conductive filler is made of at least one metal oxide selected from aluminum oxide, aluminum nitride, boron nitride and magnesium oxide, and the thermally conductive composition exhibits a resistance value of 10 ⁸ Ω or more. The heat conductive composition according to any one of claims 1 to 3.   The heat conductive composition according to claim 1, further comprising at least one selected from a dispersant, a surfactant, a plasticizer, a solvent, and an adhesion promoter.   The heat conductive composition according to claim 1, wherein the heat conductive composition is used as an adhesive and a heat dissipation material in an electronic component.   The thermally conductive composition according to claim 6, wherein the electronic component is an optical pickup portion for recording or reproduction.