JP5218375B2 - Thermally conductive composition - Google Patents

Description

  The present invention relates to a thermally conductive composition, and in particular, maintains stable syringe discharge at room temperature, and surface tack disappears in a relatively short period of time. The present invention relates to a thermally conductive composition that can prevent dripping and bleeding contamination at high temperatures.

  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 10 to 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 in the optical pickup portion during use, it is preferable that the adhesive also has a function as a heat conducting material in order to efficiently remove the heat.

  However, grease-type adhesives are basically uncured, and room temperature moisture-curing adhesives cure very slowly, causing sagging when the temperature rises, and the constituents bleed and cloud the lens There has been a problem of causing chemical contamination such as the generation of chemicals.

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 the surface tack disappears in a relatively short time, thereby preventing dust from adhering to the place of use, dripping at high temperatures, bleed contamination, etc. It is an object of the present invention to provide a heat conductive composition that can be prevented and is useful as an adhesive and a heat conductive material in an optical pickup such as a DVD.

The present invention is as follows.
1. An organic polymer composed of polyisoprene, silane-modified polyisoprene or a mixture thereof having a mean molecular weight of 1000 or more which is liquid at normal temperature, a thermoplastic resin composed of a silane-modified polyα-olefin, a petroleum resin or a mixture thereof, and the thermoplastic resin. solvent capable of dissolving the surfactant, a silane coupling agent and thermally conductive fillers, use time, keeping the inside cotton Ri liquid-like or paste-like in 1 to 72 hours in the range of 5 ° C. to 35 ° C. However, the surface becomes tackless in 10-60 minutes,
A one-pack type heat conductive composition, which is used as an adhesive and a heat dissipation material in an optical pickup portion for recording or reproduction.
2. The average molecular weight of the thermoplastic resin is 1000 or more, and the blending ratio is 1 to 40 parts by mass when the total of the organic polymer and the thermoplastic resin is 100 parts by mass. 2. The thermally conductive composition as described in 1 above.
3. 3. The thermal conductive composition according to 1 or 2 above, wherein the thermoplastic resin has at least one group selected from a hydrolyzable silicon group and an isocyanate group, and is moisture-cured at room temperature.
4). The average molecular weight of the organic polymer is 1000 or more and less than 50000, and the organic polymer has at least one group selected from a hydrolyzable silicon group and an isocyanate group, and is moisture-cured at room temperature. The heat conductive composition as described in any one of 1 to 3 above.
5. 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. 5. The heat conductive composition as described in any one of 1 to 4 above.
6). 6. The heat conductive composition as described in any one of 1 to 5 above, further comprising at least one selected from a dispersant, a surfactant, a plasticizer, a solvent, and an adhesion promoter.

  The heat conductive composition of the present invention contains an organic polymer having an average molecular weight of 1000 or more that is liquid at normal temperature, a thermoplastic resin, a solvent capable of dissolving the thermoplastic resin, and a heat conductive filler. Since it has good fluidity at the time when it is stored in the container, it is possible to maintain stable syringe discharge over a long period of time. In addition, since the surface of the heat conductive composition of the present invention is tackless in a short time during use, it is possible to prevent dust from being attached at the place of use, dripping at high temperatures, bleed contamination, and the like. Furthermore, since the interior of the heat conductive composition of the present invention is substantially liquid or pasty at room temperature for a long period of time, it can be easily repaired as needed. Furthermore, the thermal conductive composition of the present invention can be easily cut and removed with a knife or a cutter when further repair / maintenance is required after the whole is cured. The heat conductive composition of the present invention is useful as an adhesive and a heat dissipating material in an optical pickup part such as a DVD.

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

(Organic polymer having an average molecular weight of 1000 or more that is liquid at room temperature)
The organic polymer in the present invention is liquid at room temperature and has an average molecular weight of 1000 or more. The normal temperature in the present invention usually means 5 ° C. to 35 ° C. (20 ° C. ± 15 ° C .: JIS Z8703 compliant).
Examples of the organic polymer used in the present invention include diene rubbers such as polyisoprene and polybutadiene, polyisobutylene, polyoxypropylene, silicone, and acrylic polymers.
In addition, the organic polymer used in the present invention preferably has an average molecular weight of 1000 or more and less than 50000 from the viewpoints of viscosity, workability, dischargeability, and leveling properties. A more preferred average molecular weight is 2000-30000. In the present invention, the average molecular weight means the number average molecular weight measured by ASTM D2503 or the like.

The organic polymer may be a polymer having at least one group selected from a hydrolyzable silicon group and an isocyanate group and capable of moisture curing at room temperature.
In the polymer having the hydrolyzable silicon group, the hydrolyzable silicon group is a silicon-containing group that can be cross-linked by causing a condensation reaction in the presence of moisture to form a siloxane bond, for example, an alkoxysilyl group, Examples include alkenyloxysilyl group, acyloxysilyl group, aminosilyl group, aminooxysilyl group, oximesilyl group, and amidosilyl group.
Examples of the polymer having an isocyanate group include those obtained by modifying an organic polymer having at least one active hydrogen species with a polyisocyanate compound. Examples of the polypolyisocyanate compound include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and norbornane diisocyanate methyl.
In addition, you may use the polymer which has both a hydrolysable silicon group and an isocyanate group in a molecule | numerator. The bonding position of the hydrolyzable silicon group and the isocyanate group in the polymer may be the main chain terminal or the side chain. The type of monomer constituting the main chain is not particularly limited, but is preferably as exemplified above.

(Thermoplastic resin)
Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyphenylene ether, nylon, polyamide, polycarbonate, polyphenylene sulfide, polyethylene terephthalate, ABS resin, and engineering plastics. Or EVA, polyamide resin, polyolefin resin, polyester resin etc. which are used as a raw material of hot melt are mentioned. Or a resin generally called rubber, such as a styrene block copolymer, SBR, NBR, butadiene rubber, ethylene / propylene rubber, acrylic rubber, and natural rubber. As the styrene block copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-butadiene-isoprene copolymer, styrene-ethylene-butadiene copolymer, styrene-ethylene-isoprene copolymer, Examples thereof include styrene-propylene-butadiene copolymers and styrene-propylene-isoprene copolymers. Alternatively, compounds having a relatively low molecular weight, generally having a melting point and compounds called tackifiers are also preferred. For example, terpineol, menthol, acetamide, benzamide, coumarin, benzyl cinnamate, diphenyl ether, crown ether, camphor , P-methylacetophenone, vanillin, dimethoxybenzaldehyde, p-benzylbiphenyl, stilbene, margaric acid, eicosanol, cetyl palmitate, stearamide, behenylamine, and other monomolecular compounds, beeswax, candelilla wax, paraffin wax, ester Waxes such as wax, montan wax, carnauba wax, amide wax, polyethylene wax, microcrystalline wax, ester gum, logistic Rosin derivatives such as maleic acid resin, rosin phenol resin, phenol resin, ketone resin, urethane resin, epoxy resin, diallyl phthalate resin, terpene hydrocarbon resin, cyclopentadiene resin, polyolefin resin, polycaprolactone resin, polyethylene glycol, Examples thereof include polymer compounds typified by polyolefin oxides such as polypropylene glycol.
Examples of the blending ratio of the thermoplastic resin include 1 to 40 parts by mass with respect to 100 parts by mass of the liquid component.

The thermoplastic resin may be a resin that has at least one group selected from a hydrolyzable silicon group and an isocyanate group and is moisture-cured at room temperature.
In the thermoplastic resin having a hydrolyzable silicon group, the hydrolyzable silicon group is a silicon-containing group that can be cross-linked by causing a condensation reaction in the presence of moisture to form a siloxane bond. Group, alkenyloxysilyl group, acyloxysilyl group, aminosilyl group, aminooxysilyl group, oximesilyl group, and amidosilyl group.
Examples of the polymer having an isocyanate group include those obtained by modifying a resin having at least one active hydrogen species with a polyisocyanate compound. Examples of the polypolyisocyanate compound include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and norbornane diisocyanate methyl.
In addition, you may use the thermoplastic resin which has both a hydrolysable silicon group and an isocyanate group in a molecule | numerator. Further, the bonding position of the hydrolyzable silicon group and the isocyanate group in the thermoplastic resin may be the end of the main chain or the side chain. The type of monomer constituting the main chain is not particularly limited, but is preferably as exemplified above.

(Solvent that can dissolve thermoplastic resin)
There is no restriction | limiting in particular as a solvent which can melt | dissolve the said thermoplastic resin, The thing which can melt | dissolve each thermoplastic resin can be used suitably. Solvents 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 are mainly used. Examples thereof include aromatic hydrocarbons such as toluene and xylene, and chlorinated solvents such as methylene chloride.

(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, 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. Of these, aluminum oxide, aluminum nitride, boron nitride, and magnesium oxide are preferred in the present invention.

  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.

(Mixing ratio)
In the thermally conductive composition of the present invention, the blending ratio of the thermoplastic resin is preferably 1 to 40 parts by mass, preferably 5 to 20 parts by mass, when the total of the organic polymer and the thermoplastic resin is 100 parts by mass. Is more preferable.
Further, the blending ratio of the solvent capable of dissolving the thermoplastic resin is preferably 10 to 500 parts by mass, and more preferably 50 to 300 parts by mass with respect to 100 parts by mass of the thermoplastic resin.
Further, 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 liquid component.

When used, the droplets of the composition of the present invention quickly evaporate the solvent, form a thermoplastic resin film in a short time, and become tackless. Accordingly, it is possible to prevent dust from adhering to the place of use, liquid dripping at high temperatures, bleed contamination, and the like, and repairs can be easily performed as necessary.
In particular, when the thermoplastic resin has at least one group selected from a hydrolyzable silicon group or an isocyanate group and is moisture-cured at room temperature, it is advantageous for long-term dust adhesion. This is advantageous in terms of bleed suppression effect and repairability.
Further, when the organic polymer has at least one group selected from a hydrolyzable silicon group and an isocyanate group and is moisture-cured at room temperature, the moisture curing of the organic polymer forming the inner portion proceeds slowly. In addition, since it is liquid or pasty for a long period of time, it is possible to ensure syringe discharge for a long period of time, and in some cases it is excellent in repairability. Further, since the flexibility is maintained by the organic polymer, The effect that the impact resistance at the time of fall can be eased is further produced.

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 surfactant, 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 a low molecular weight dispersant, fatty acid salt (soap), MES, ABS, LAS, AS, AES, alkylsulfuric triethanolamine, etc. as anionic, fatty acid diethanolamide, AE [higher alcohol], APE, Alkyltrimethylammonium salt, dialkyldimethylammonium chloride, alkylpyridinium chloride as the cationic system, alkylcarboxybetaine [betaine system] as the amphoteric system, etc. are used. 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 d-limonene, 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, ethers such as butyl cellosolve, toluene, chlorinated solvents such as aromatic hydrocarbons, methylene chloride, such as xylene.
Examples of the adhesion-imparting agent include terpene resins, phenol resins, terpene-phenol resins, rosin resins, xylene resins, epoxy resins or silane coupling agents, titanate coupling agents, and isocyanate compounds.
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.

When used, the composition of the present invention maintains a substantially liquid or pasty state at room temperature for a long period of time. The normal temperature in the present invention usually means 5 ° C. to 35 ° C. (20 ° C. ± 15 ° C .: JIS Z8703 compliant).
The long term here is, for example, 1 hour to 72 hours. Further, the surface becomes tackless in a short time. The short time here is, for example, 10 minutes to 60 minutes.

The composition of the present invention can be used as a one-component composition.
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. The optical element in the optical pick-up part for recording or reproduction of DVD, etc. from the point that the surface tack disappears in a relatively short time and can prevent dust adhesion at the point of use, liquid sag and bleed contamination at high temperature, etc. It is useful as an adhesive and heat dissipation material.

  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 filler aggregate was crushed and further subjected to a detreatment method to prepare the composition of the present invention. In addition, the composition of this invention was prepared by the compounding ratio shown in Table 1 being a mass part. In addition, the mixture ratio shown in Table 1 is a mass part.

Details of various components in Table 1 are shown below.
Poly iP: Polyisoprene manufactured by Idemitsu Kosan Co., Ltd. Number average molecular weight = 2500. Liquid at room temperature.
Poly iP + y 5187: Polyisoprene with hydroxyl terminal produced by Idemitsu Kosan Co., Ltd. Poly iP: 100 parts by weight of 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.
Best Plus Application: Evonik Degussa silane modified poly α- olefins. Number average molecular weight = 10,000.
Quinton G1671: C5 petroleum resin manufactured by Nippon Zeon.
Woody River # 8: d-limonene manufactured by Yashara Chemical Company.
Disparon 1761: Surfactant manufactured by Enomoto Kasei Co., Ltd.
A174: Methacrylate silane manufactured by Momentive Performance Materials.
AS-400: Aluminum oxide manufactured by Showa Denko KK Particle size = 12 μm
NO. 918: A tin catalyst manufactured by Sansha Co., Ltd.

About each composition prepared as described above, surface tackiness after 20 hours at 20 ° C (20 ° C, 1H surface tack), surface tackiness after 20 hours at 20 ° C (20 ° C, 12H surface tack), Syringe discharge properties after 20 days at 20 ° C. (20 ° C. 1 day syringe discharge properties), syringe discharge properties after 20 days at 20 ° C. (20 ° C. 3 days syringe discharge properties), bleeding properties, and repair properties were examined. The results are also shown in Table 1.
The surface tackiness was examined by finger touch.
Syringe discharge is as follows: After filling a syringe with a compound, a small amount is discharged from the tip of the needle, left for a predetermined time (1 day and 3 days), and then the pressure of 0.5 MPa is applied to the needle tip. Those that could be discharged from the nozzle were OK, and those that could not be discharged because the tip of the needle was hardened were judged as NG.
The bleed property was evaluated by dropping 1.5 ml of the composition on a filter paper as a circle having a diameter of about 30 mm under an environment of 70 ° C. and measuring the length of the bleed portion after 24 hours. 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).
In the evaluation of bleedness, the case of 5 mm or less was OK, and the case of bleedability was NG.
For repairability, 0.5 g of the composition is placed on a glass plate in a cylindrical shape with a diameter of about 5 mm, and what can be easily removed by pinching the ends with tweezers after 70 hours at 70 ° C is OK. The case where it cannot be removed without applying a considerable force such as applying an impact by applying the tip or the like, or the case where the composition remaining as a grace deposit remains after the removal is determined as NG.

From the results shown in Table 1, the surface tack of the composition of the present invention disappears in a relatively short time. This indicates that it is possible to prevent dust from adhering to the place of use, dripping at high temperatures, bleed contamination, and the like, and as can be seen from the repair test results, it is easy to perform repairs as necessary. . It was also found that the syringe discharge property at room temperature was stable for a long time and the bleed property was excellent.
On the other hand, the compositions of Comparative Examples 1 and 2 could not satisfy both the surface tackiness, the syringe discharge property, the bleed property, and the repair property.

Claims (6)

An organic polymer composed of polyisoprene, silane-modified polyisoprene or a mixture thereof having a mean molecular weight of 1000 or more which is liquid at normal temperature, a thermoplastic resin composed of a silane-modified polyα-olefin, a petroleum resin or a mixture thereof, and the thermoplastic resin. solvent capable of dissolving the surfactant, a silane coupling agent and thermally conductive fillers, use time, keeping the inside cotton Ri liquid-like or paste-like in 1 to 72 hours in the range of 5 ° C. to 35 ° C. However, the surface becomes tackless in 10-60 minutes,
A one-pack type heat conductive composition, which is used as an adhesive and a heat dissipation material in an optical pickup portion for recording or reproduction.   The average molecular weight of the thermoplastic resin is 1000 or more, and the blending ratio is 1 to 40 parts by mass when the total of the organic polymer and the thermoplastic resin is 100 parts by mass. The thermally conductive composition according to claim 1.   The thermally conductive composition according to claim 1 or 2, wherein the thermoplastic resin has at least one group selected from a hydrolyzable silicon group and an isocyanate group, and is moisture-cured at room temperature. .   The average molecular weight of the organic polymer is 1000 or more and less than 50000, and the organic polymer has at least one group selected from a hydrolyzable silicon group and an isocyanate group, and is moisture-cured at room temperature. The heat conductive composition according to any one of claims 1 to 3.   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 108Ω or more. The thermally conductive composition according to any one of claims 1 to 4.   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.