KR20050102208A - Acryl type heat-radiation pad - Google Patents

Abstract

The present invention relates to an acrylic heat-dissipating pad, wherein the ethylenically unsaturated carboxylic acid alkyl ester monomer + ethylenically unsaturated carboxylic acid monomer having an ethylene unsaturated carboxylic acid monomer portion of 0 to 10 parts by weight and a viscosity of 500 to 10,000 centipoise Or 100 parts by weight of copolymer oligomer (forwardly "acrylic oligomer"); 0.2 to 2 parts by weight of photoinitiator; 50 to 250 parts by weight of thermally conductive inorganic powder; 0.03 to 0.15 parts by weight of an unsaturated carboxylic acid alkyl ester of an alkanediol or a polyol having a hydroxy group at a sock end; 0.05 to 10 parts by weight of an ethylenically unsaturated carboxylic acid, aryl or aralkyl ester monomer, ethylene amide or ethylene amine substituted with a hydroxy group as a nucleophilic thermal reactive crosslinking component; 0.5-4 parts of the glycidyl compound or alkyl, aryl or aralkyl peroxide or maleic anhydride are completely mixed in the form of a paste as an electrophilic thermally reactive crosslinking component. The paste is coated on a release paper and irradiated with UV light to cure the light. It provides an acrylic self-adhesive heat dissipation pad prepared by reacting.

The acrylic type heat dissipation pad of the present invention has a relatively low hardness at room temperature while showing high temperature heat resistance and high front adhesive force between the aluminum and the glass plate. The heat dissipation pad has a constant modulus value, which is easy to handle and gradually hardens in a high temperature environment, thereby maintaining strength.

Description

Acrylic heat dissipation pad {Acryl type heat-radiation pad}

The present invention relates to an acrylic heat dissipating pad. In particular, the present invention relates to an acrylic heat dissipating pad excellent in heat resistance and adhesion and easy to store and handle.

If heat from the electronics does not flow smoothly to the heat sink, it can cause expensive electronic devices to fail. In the display field, especially in the case of PDPs, cooling of the panel by smooth heat flow becomes an important factor for the stability of the device as the heat generation amount is increased by the high voltage discharge structure. Therefore, the prior art discloses various thermally conductive sheets for smooth heat flow between the glass panel of the PDP and the aluminum sash, which is a heat sink.

Such a thermally conductive tape is variable in shape due to adhesiveness, but does not provide heat resistance that can be endured in a high temperature use environment, or when heat resistant, there is a problem in that a separate adhesive component is bonded to a surface because it is not adhesive.

The present inventors design the adhesive composition to have both photocuring and thermosetting properties in a range of viscosities of acrylic oligomers that can form a paste state by mixing thermally conductive materials, and provide an adhesive heat dissipation pad by a photocuring reaction to crosslink in an environment of use. The present invention has been completed in view of the fact that it can be used as a heat dissipation pad requiring heat resistance and adhesiveness at the same time by thermal curing by reaction. The present invention provides a self-adhesive acrylic heat-dissipating pad that does not require a conventional pressure-sensitive adhesive bonding process as a heat dissipation sheet to improve the adhesion between the heating element and the heat sink to uniform heat distribution. The present invention has a relatively low hardness at room temperature, and has a high adhesion rate, and at a high temperature, an acrylic cross-linking reaction occurs additionally, and is designed to have high temperature heat resistance so that it can be mounted on a PDP glass panel and an aluminum chassis. To provide a heat radiation pad.

According to the present invention, an acrylic single or copolymer oligomer of an ethylene unsaturated carboxylic acid alkyl ester monomer + an ethylenically unsaturated carboxylic acid monomer having an ethylene unsaturated carboxylic acid monomer portion of 0 to 10 parts by weight and a viscosity of 500 to 10,000 centipoise. (Forward "acrylic oligomer") 100 parts by weight; 0.2 to 2 parts by weight of photoinitiator; 50 to 250 parts by weight of thermally conductive inorganic powder; 0.03 to 0.15 parts by weight of an unsaturated carboxylic acid alkyl ester of an alkanediol or a polyol having a hydroxy group at a sock end; 0.05 to 10 parts by weight of an ethylenically unsaturated carboxylic acid, aryl or aralkyl ester monomer, ethylene amide or ethylene amine substituted with a hydroxy group as a nucleophilic thermal reactive crosslinking component; 0.5-4 parts of the glycidyl compound or alkyl, aryl or aralkyl peroxide or maleic anhydride are completely mixed in the form of a paste as an electrophilic thermally reactive crosslinking component. The paste is coated on a release paper and irradiated with UV light to cure the light. An acrylic self-adhesive heat dissipation pad prepared by reacting is provided.

The unsaturated carboxylic acid alkyl ester monomer used in the acrylic oligomer which is the main component of the present invention is methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, dimethyl fumarate, diethyl fumarate, Dimethyl maleate, dimethyl itaconate, monomethyl fumarate, monoethyl fumarate, 2-ethylhexyl acrylate and the like. Preferably methyl acrylate, methyl methacrylate, ethyl acrylate or ethyl methacrylate and most preferably ethyl methacrylate.

 Examples of the ethylenically unsaturated carboxylic acid monomer used in the acrylic oligomer which is the main component of the present invention include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid. Preferably acrylic acid. Preferably 1 to 6 parts by weight of acrylic acid is used in the copolymer oligomer.

Photoinitiators are, for example, benzophenone, chloroacetophenone, diethoxyacetophenone, hydroxyacetonephenone, 1-hydroxy cyclohexylphenyl ketone, benzoin ether, benzyldimethyl ketal, thioxanthone or mixtures thereof. Preferably from 0.3 to 1 part by weight of 1-hydroxy cyclohexylphenyl ketone is used.

Thermally conductive inorganic powders are oxides, carbides, silicides, nitrides, borides, carbonitrides, hydroxides or graphite carbons or mixtures of metals or metalloids. For example, alumina, zinc oxide, aluminum hydroxide, silicon carbide, magnesia, boron nitride, graphite carbon, silicon carbide and the like. The blending amount of the filler is used in a range that can protect the hardness and adhesive strength of the heat radiation pad, and 50 to 250 parts by weight, preferably 70 to 150 parts by weight based on 100 parts by weight of the acrylic oligomer.

Unsaturated carboxylic acid alkyl esters of alkane diols or polyols having hydroxy groups at the end of the socks include HDDA (1,6-Hexanediol Diacrylate; 1,6-hexanedioldiacrylate), HD (EO) DA (1,6-Hexanediol ( ethoxylated) diacrylate; 1,6-hexanediol ethoxylated diacrylate), BDDA (1,4-Buthanediol diacrylate; 1,4-butanediol diacrylate), TEGDA (Tetraethylene glycol diacrylate); HPNDA (Hydroxy pivalic acid neopentyl glycol diacrylate; hydroxy pivalic acid neopentyl glycol diacrylate), TPGDA (tripropylene glycol diacrylate; tripropylene glycol diacrylate), DPGDA (Dipropylene glycol diacrylate; dipropylene glycol diacrylate), PEGDA (Polyethylene glycol diacrylate), PTMGDA (polyethylene glycol diacrylate), BPA (EO) DA (Bisphenol A (ethoxylated) diacrylate; bisphenol A ethoxylated diacrylate), TMPTA (trimethylolpropane triacrylate) Pantrialkylate), GPTA (Glycerin propoxylated triacrylat; glycerin propoxylated triacrylate), PETA (pentaerythritol triacrylate; pentaerythritol triacrylate), DPPA (Dipentaerythritol pentaacrylate; dipentaerythritol pentaacrylate), DPHA (DPHA) Dipentaerythritol hexaacrylate; dipentaerythritol hexaacrylate). Preferably, 0.05 to 0.2 parts by weight of HDDA is used.

Monomers containing hydroxy alkyl groups as nucleophilic thermally reactive crosslinking components include 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acryl Ethylene, hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate and 2-hydroxy-3-phenoxypropyl acrylate may be used, and acryl amide and ethylene amine may be used. Amides, methacrylamides, N-methylolacrylamides, N-methylolmethacrylamides, N, N-dimethylacrylamides and their corresponding amines can be used. Preferably 0.3 to 1 parts by weight of acrylamide is used.

In addition, glycidyl acrylate, glycidyl methacrylate, methylglycidyl acrylate, allyl glycidyl ether, etc. may be used as the glycidyl compound as the electrophilic thermally reactive crosslinking component. As electrophilic alkyl, aryl or aralkyl peroxide, tert-butyl peroxybenzoate, di-ter-butyl peroxide, lauryl peroxide, benzoic peroxide and the like are used. Maleic anhydride may also be used. Preferably 1 to 3 parts by weight of glycidyl methacrylate is used.

The acrylic oligomer, the thermally conductive inorganic powder, the photoinitiator, and other additives are mixed to form a paste solution. The viscosity at this time is about 500 to 10,000 cps. The mixed solution thus made is evenly applied using a laminator on the release treated paper. After application, the viscosity is about 500 to 50,000 cps, preferably 1000 to 10,000 cps, and then cured in the UV region for 10 seconds to 10 minutes, and then wound through a release paper to form a heat radiation pad having a thickness of 0.2 to 3 mm and preferably 0.5 to 2 mm. .

Such a heat dissipating pad is applied by adhesion at room temperature, and when exposed to a high temperature use environment, crosslinking is performed by a reaction of a thermally reactive crosslinking component, for example, ring-opening reaction of glycidyl, and thus has heat resistance.

Hereinafter, the raw material of the present invention and the heat dissipation pad of the present invention will be described in detail with reference to Preparation Examples and Examples.

Preparation Example 1

Preparation of Acrylic Oligomer (1)

As described in Table 1, 90 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, and 0.05 parts of photoinitiator were added, placed in a reactor equipped with a high speed stirrer, and stirred under nitrogen. After stirring, photoreaction was carried out under a 365 nm wavelength to obtain an acrylic oligomer so as to have a desired viscosity (20 ° C) of 5000 to 10000 cps. The total stirring time was about 10 minutes and the light reaction time was about 1 to 5 minutes.

The average molecular weight of the oligomer thus obtained could be obtained by the following method, which was generally in agreement with the viscosity value centipoise.

<Acrylic oligomer average molecular weight measurement conditions>

It was measured using gel permission chromatography (water 2410) in a conventional manner.

Production Examples 2 to 5

Manufacture of acrylic oligomers (2,3,4,5)

After the monomers were improved in the ratios shown in Table 1, acrylic oligomers (2), (3), (4) and (5) were prepared by the same method as in Preparation Example 1.

TABLE 1

Oligomer (1) Oligomer (2) Oligomer (3) Oligomer (4) Oligomer (5) 2-ethylmethacrylate 90 94 96 98 100 Acrylic acid 10 6 4 2 0 Photoinitiator 0.05 0.05 0.1 0.05 0.2 Viscosity (cps) 6200 6250 6100 6500 6700

In the following Examples will be described with respect to the heat radiation pad manufactured using the acrylic oligomer (1, 2, 3, 4, 5) prepared above.

Example 1

Using the acrylic oligomer prepared in Preparation Example 4 was prepared as follows.

100 parts of acrylic oligomers (production example 4)

IRGAQURE 184 ¹⁾ 0.5 part

Aluminum hydroxide ²⁾ 80 parts

HDDA ³⁾ 0.1 part

1.5 parts glycidyl methacrylate

Acrylamide0.5part

(Wherein ※ ¹⁾ IRGAQURE 184 is 1-hydroxycyclohexyl phenyl ketone as a trade name from Ciba Specialty Corp. is ²⁾ aluminum hydroxide ATH3300 ³⁾ of HDDA west longitude CMT is the M200 Miwon boss)

The above is stirred using a stirrer to form a paste. The viscosity at this time shows a viscosity of about 5,000 to 10,000 cps. The mixed paste thus produced is uniformly applied on a 75 μm PET film subjected to a cross-sectional release using a laminator. After coating, the curing reaction in the UV region (wavelength: 365 nm) for 3 minutes and then wound through a release paper to make a heat radiation pad of 1.5mm thickness.

<Production sheet evaluation>

The release paper LINER of the heat radiation pad was removed to obtain the following physical properties.

ASKER C Hardness: 19

Shear force between glass surfaces: 11 kgf / in ²

Tensile Strength: 1.5 kgf / 25mm (Adhesive: Glass)

Thermal Conductivity: 0.52 W / m.K

<Heat Resistance Test>

The sample is cut to 1 cm in width and attached to a glass plate (2.5 cm * 5 cm) (the glass plate is attached to both sides of the heat dissipation pad), and then pressed once with a force of 5 kgf. Install 50g weight on one glass surface. Leave at room temperature for 1 hour. Install in a convection oven at 120 ℃ and measure the time when the additional glass surface is detached from the heat radiation pad. The result is as follows.

Measurement time: 1000 hours or more

Example 2

Except for using the acrylic oligomer prepared in Preparation Example 3 and using 150 parts of aluminum hydroxide to produce a heat radiation pad using the same method as in Example 1.

<Production sheet evaluation>

      The release paper LINER of the heat radiation pad was removed to obtain the following physical properties.

ASKER C Hardness: 29

Thermal Conductivity: 0.91 W / m.K

The heat resistance test was performed as in <heat resistance test> of Example 1. The result was more than 1000 hours.

 Example 3

Except for using the acrylic oligomer prepared in Preparation Example 5 and using 45 parts of aluminum hydroxide and 105 parts of silicon carbide instead of 80 parts of aluminum hydroxide to make a heat radiation pad using the same method as in Example 1.

<Production sheet evaluation>

The release paper LINER of the heat radiation pad was removed to obtain the following physical properties.

ASKER C Hardness: 28

Thermal Conductivity: 1.12 W / m.K

The heat resistance test was performed as in <heat resistance test> of Example 1. The result was more than 1000 hours.

The acrylic type heat dissipation pad of the present invention has a relatively low hardness at room temperature while showing high temperature heat resistance and high front adhesive force between the aluminum and the glass plate. The heat dissipation pad has a constant modulus value, which is easy to handle and gradually hardens in a high temperature use environment to maintain strength.

Claims (5)

100 parts by weight of an acrylic single or copolymer oligomer of an ethylenically unsaturated carboxylic acid alkyl ester monomer + an ethylenically unsaturated carboxylic acid monomer having an ethylene unsaturated carboxylic acid monomer portion of 0 to 10 parts by weight and a viscosity of 500 to 10,000 centipoise; 0.1 to 2 parts by weight of photoinitiator; 50 to 250 parts by weight of thermally conductive inorganic powder; 0.03 to 0.15 parts by weight of an unsaturated carboxylic acid alkyl ester of an alkanediol or a polyol having a hydroxy group at a sock end; 0.05 to 10 parts by weight of an ethylenically unsaturated carboxylic acid, aryl or aralkyl ester monomer substituted with a hydroxy group as a nucleophilic thermal reactive crosslinking component, ethylene amide, and ethylene amine; 0.5-3 parts by weight of a glycidyl compound or an electrophilic alkyl, aryl or aralkyl peroxide or maleic anhydride as a electrophilic thermally reactive crosslinking component is completely mixed so as to paste into a paste state and the paste is coated on a release paper and UV light is applied. An acrylic self-adhesive heat dissipation pad prepared by irradiation and photocuring reaction. The method of claim 1, wherein the unsaturated carboxylic acid alkyl ester monomer used in the acrylic oligomer is methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, dimethyl fumarate, diethyl fumarate, The ethylenically unsaturated carboxylic acid monomers selected from the group consisting of dimethyl maleate, dimethyl itaconate, monomethyl fumarate, monoethyl fumarate, 2-ethylhexyl acrylate and mixtures thereof are used in the acrylic oligomer. It is selected from the group consisting of krylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and mixtures thereof; The photoinitiator is selected from the group consisting of benzophenone, chloroacetophenone, diethoxyacetophenone, hydroxyacetonephenone, 1-hydroxy cyclohexylphenyl ketone, benzoin ether, benzyldimethyl ketal, thioxanthone or mixtures thereof ; The thermally conductive inorganic powder is selected from the group consisting of alumina, zinc oxide, aluminum hydroxide, silicon carbide, magnesia, boron nitride, graphite carbon, silicon carbide and mixtures thereof; The unsaturated carboxylic acid alkyl ester of the polykan having a hydroxyl group at the alkanediol or the sock end is HDDA (1,6-Hexanediol Diacrylate; 1,6-hexanedioldiacrylate), HD (EO) DA (1,6-Hexanediol (ethoxylated) diacrylate; 1,6-hexanediol ethoxylated diacrylate), BDDA (1,4-Buthanediol diacrylate; 1,4-butanediol diacrylate), TEGDA (tetraethylene glycol diacrylate) , HPNDA (Hydroxy pivalic acid neopentyl glycol diacrylate; hydroxy pivalate neopentyl glycol diacrylate), TPGDA (tripropylene glycol diacrylate; tripropylene glycol diacrylate), DPGDA (Dipropylene glycol diacrylate), PEGDA (polyethylene glycol diacrylate), PTMGDA (polyethylene glycol diacrylate), BPA (EO) DA (Bisphenol A (ethoxylated) diacrylate; bisphenol A ethoxylated diacrylate), TMPTA (trimethylolpropane triacrylate; trimethyl Propanetrialkylate), GPTA (Glycerin propoxylated triacrylat; glycerin propoxylated triacrylate), PETA (pentaerythritol triacrylate; pentaerythritol triacrylate), DPPA (Dipentaerythritol pentaacrylate; dipentaerythritol pentaacrylate) or DPHA ( Dipentaerythritol hexaacrylate; dipentaerythritol hexaacrylate); As the nucleophilic thermoreactive crosslinking component, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacryl Latex, 3-chloro-2-hydroxypropylmethacrylate and 2-hydroxy-3-phenoxypropylacrylate, acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N, N-dimethylacrylamide, acrylamine, methacrylamine, N-methylolacrylamine or N-methylolmethacrylamine, N, N-dimethylacrylamine; and the electrophilic thermally reactive crosslinking component is glycy Dilacrylate, glycidyl methacrylate, methylglycidyl acrylate, allylglycidyl ether, tert-butyl peroxybenzoate, di-ter-butyl peroxide, lauryl peroxide, benzoic peroxide or Male Anhydride, an acrylic self-adhesive thermal pad. The unsaturated carboxylic acid alkyl ester monomer used in the acrylic oligomer is ethyl methacrylate, the ethylenically unsaturated carboxylic acid monomer used in the acrylic oligomer is acrylic acid, and the photoinitiator is 1-hydroxy. The hydroxy cyclohexylphenyl ketone and the alkanediol, the polyol having a hydroxy group at the sock end or their unsaturated carboxylic acid alkyl ester is HDDA and the nucleophilic thermal reactive crosslinking component is acrylamide; and the electrophilic thermal reactive crosslinking component is glycy Acrylic self-adhesive heat radiation pad which is a diacrylate. The method of claim 3, wherein the ethylenically unsaturated carboxylic acid monomer used in the acrylic oligomer is 1 to 6 parts by weight of the acrylic oligomer; The photoinitiator 0.3 to 1 part by weight; The thermally conductive inorganic powder is 70 to 150 parts by weight; Alkanediol, the polyol which has a hydroxyl group in a sock end, or these unsaturated carboxylic acid alkyl esters are 0.05-0.2 weight part; The nucleophilic thermally reactive crosslinking component is 0.3 to 1 part by weight; and the electrophilic thermally reactive crosslinking component is 1 to 3 parts by weight of an acrylic self-adhesive heat dissipating pad. The method of claim 4, wherein the thickness of the viscosity of about 1,000 to 10,000 cps prepared by applying a laminator on the paste-treated release paper using a laminator and winding through the release paper after the curing reaction in the UV region for 2 to 5 minutes mm acrylic self-adhesive heat-resistant pad.