KR102075461B1 - Liquid silicone composition with high heat dissipation - Google Patents

Abstract

The present invention relates to a high heat dissipation liquid silicone composition, to a silicone composition having a high heat dissipation characteristics and to an automotive part sealed using the same.

Description

High heat dissipation liquid silicone composition {LIQUID SILICONE COMPOSITION WITH HIGH HEAT DISSIPATION}

TECHNICAL FIELD The present invention relates to a high heat dissipation liquid silicone composition, and to a silicone composition having high heat dissipation properties, a molding made therefrom, and a sealed automotive part.

The UN Climate Change Convention and the recently entered into force of the Kyoto Protocol mandate mandatory reductions in greenhouse gases for Korea and other countries around the world. Accordingly, the Korean government has taken various measures to reduce greenhouse gases. In particular, the government has imposed various regulations on automobiles, one of the biggest sources of greenhouse gas emissions, and the automobile industry is responding to the development of electric vehicles.

An electric vehicle refers to a vehicle using electricity as a main power source and a vehicle having a system for charging electricity to a battery and supplying the motor to a driving source. For example, a rechargeable electric vehicle, a hybrid vehicle, a fuel cell vehicle, etc. are mentioned.

Recently, due to packaging limitations and battery energy storage problems in electric vehicles, the compact and highly efficient design of components is emerging as an important issue. In particular, heat dissipation issues are increasing due to the compactness of parts, but most of the high heat dissipation materials suitable for the heating value of automobile parts required in the current era are dependent on imports.

An electric vehicle accumulates electric energy in a battery, which is a secondary battery, and converts the electric energy into power energy using a motor. At this time, the electric energy is charged to the battery by the rapid charging method of directly applying the DC high voltage power (about 50kW or more) directly to the battery and by the slow application of AC power (about 3 ~ 6kW) having a commercial AC voltage. There is a charging method.

However, in general, the voltage of power obtained in a general home is AC 100-240V, and a battery mounted in an electric vehicle has a DC voltage of DC 240-413V, which is a relatively high voltage. Therefore, in order to commercialize and practically use environmentally friendly electric vehicles, a charging device capable of efficiently converting commercial AC power obtained at home into high voltage DC power, a so-called "On-Board Charger; OBC) "continues to be developed.

In addition to the OBC, a low voltage DC converter (LDC) is installed in the electric vehicle, and the electric equipment of the vehicle is operated by the power of the battery, and the power of the battery operates the motor through the inverter and gives driving power to the vehicle. The OBC, LDC, inverter and motor are all electric components that generate heat during operation, and heat is diffused by using a heat dissipator for the purpose of protecting the components from heat generation.

Automotive heat insulators are used in harsh environments and are subject to vibration, requiring heat resistance, cold resistance and vibration resistance. As a conventional automotive heat dissipating material, fillers such as epoxy resin, acrylic resin, cycloolefin resin, polyphenylene sulfide (polyphenylene sulfide), PVC (polyvinyl chloride), urethane resin, silicone resin, etc. Use it thickly. The filler is for improving the low thermal conductivity of the resin itself, and is generally used with high filling of a ceramic filler having excellent thermal conductivity. However, when the filler is high-filled, the resin moldability is sharply lowered, thereby reducing the flexibility of the heat dissipation material, and the adhesive strength is also lowered. In addition, as the filler is highly filled, the viscosity is increased, and thus it is impossible to utilize the material as a heat-dissipating molding material that is used by potting in a device such as an automobile OBC.

Until recently, it is difficult to manufacture a high heat radiation material having a thermal conductivity of 3 W / m · K or more, and in particular, there is a limit in implementing a high heat radiation material having high thermal conductivity while maintaining adhesiveness.

Korean Patent Publication No. 10-1776324

It is an object of the present invention to provide a high heat dissipation silicone liquid composition having excellent thermal conductivity properties.

Another object of the present invention is to provide a high heat dissipating silicone liquid composition having excellent adhesive strength and elongation.

Another object of the present invention is to provide a high heat dissipation silicone liquid composition which may have fluidity and maintain a liquid state even though a high content of heat dissipation filler is included.

Another object of the present invention is to provide a high heat dissipation silicone liquid composition which can be used by potting in an automobile device.

The high heat dissipation silicone liquid composition according to the present invention for achieving the above object includes a polysiloxane, an acrylic polysiloxane, an epoxy alkoxy silane and a heat dissipation filler.

In one embodiment of the present invention, the polysiloxane is a mixture of low and high viscosity polysiloxane, and the mixture may include at least one vinyl-based polysiloxane.

In one aspect of the present invention, the heat dissipation filler may be a mixture of boron nitride and a metal oxide.

In one embodiment of the present invention, the metal oxide may be spherical alumina having an average particle diameter of 0.5 to 200 μm.

In one aspect of the invention the spherical alumina may be characterized in that the particle size distribution is trimodal (trimodal).

In one embodiment of the present invention, the particle size distribution may satisfy the following Equations 1 and 2 below.

1.1 <D ₁ / D ₂ <10

10.1 <D ₁ / D ₃ <30

(Wherein D ₁ , D ₂ and D ₃ are the average particle diameters of the different aluminas, respectively.)

In one embodiment of the present invention, the high heat dissipation liquid silicone composition may include 1 to 20% by weight of polysiloxane, 0.1 to 5% by weight of acrylic polysiloxane, 0.1 to 10% by weight of epoxy-based alkoxy silane and 75 to 95% by weight of heat dissipation filler. .

In one aspect of the present invention, the high heat dissipation liquid silicone composition may have a viscosity of 15,000 cP or less according to ASTM D1084.

Another aspect of the present invention is a high heat radiation molded article produced by curing the high heat radiation liquid silicone composition.

In one aspect of the present invention, the molded article may have an elongation of 20% or more according to ASTM D412.

In one aspect of the present invention, the molded article may have a thermal conductivity of 3.0 W / m · K or more according to ASTM E1461.

In one aspect of the present invention, the molded article may be one having an adhesive strength of 50 Kgf / cm ² or more according to ASTM D816.

Another aspect of the invention is an automotive part sealed using the high heat dissipation liquid silicone composition.

The high heat dissipation liquid silicone composition according to the present invention exhibits excellent heat resistance, voltage resistance, and durability, and has high thermal conductivity, thereby being used in components embedded in electronic products such as LED chips, semiconductor chips, plastic substrates, computers, and plasma display panels. The effect of dissipating heat quickly and protecting parts is excellent.

The high heat dissipation liquid silicone composition according to the present invention has the advantage that it can be used by potting inside a device including a heating element as a high heat dissipation material having a low viscosity, and specifically, it can be used as a high heat dissipation molding material of a vehicle.

The high heat dissipation liquid silicone composition according to the present invention is to provide a high heat dissipation silicone liquid composition that can be used by curing after molding to various types of electronic components by maintaining a liquid state with fluidity even though a high content of heat dissipation filler.

The high heat dissipation liquid silicone composition according to the present invention has an advantage in that it can be utilized in an electronic component material field requiring high heat dissipation adhesive due to its excellent adhesive strength.

DETAILED DESCRIPTION Hereinafter, the present invention will be described in more detail with reference to the accompanying examples or embodiments. However, the following specific examples or examples are only one reference for describing the present invention in detail, but the present invention is not limited thereto and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the description in the present invention are only for effectively describing specific embodiments and are not intended to limit the present invention.

Also, the singular forms used in the specification and the appended claims may be intended to include the plural forms as well, unless the context clearly indicates otherwise.

Also, unless otherwise defined in the specification and claims, weight should be the basis, and% and ratio, which are not defined as an example, refer to the form of weight percentage or weight ratio.

The high heat dissipating silicone liquid composition according to the present invention relates to a composition comprising a polysiloxane, an acrylic polysiloxane, an epoxy alkoxy silane and a heat dissipating filler.

In one aspect of the present invention, polysiloxane is used as a binder for fixing a heat dissipation filler as a base resin of a high heat dissipation material. The polysiloxane is not limited, but the weight average molecular weight is 2,000 ~ 100,000 g / mol, the viscosity measured at 25 ℃ can be used 30 to 10,000 cP, specifically, the weight average molecular weight is 3,000 to 50,000 g / mol, It may be to use a viscosity of 50 ~ 5,000 cP.

The polysiloxane content in the high heat dissipation liquid silicone composition may be used in an amount of 1 to 20 wt%, specifically 3 to 15 wt%, more specifically 5 to 12 wt%, but is not limited thereto.

The polysiloxane having physical properties and contents in the above ranges provides excellent heat resistance, voltage resistance, and durability as a high heat dissipating material, and may have fluidity even when a high content of heat dissipation filler is included, as described below. As it can be manufactured as a molding material there is an advantage that can be utilized.

In one aspect of the present invention, the polysiloxane may be a mixture of low viscosity polysiloxane and high viscosity polysiloxane, and the mixture may include at least one vinyl-based polysiloxane.

The low viscosity polysiloxane may have a viscosity measured at 25 ° C. of 30 to 3,000 cP, specifically 40 to 1,000 cP, and more specifically 50 to 500 cP, but is not limited thereto. In addition, the high viscosity polysiloxane may have a viscosity measured at 25 ° C. of 100 to 10,000 cP, specifically 300 to 5,000 cP, more specifically 500 to 3,000 cP, but is not limited thereto. More specifically, the viscosity ratio of the low viscosity polysiloxane and the high viscosity polysiloxane may be 1: 4 to 350, specifically 1: 5 to 150, and more specifically 1:10 to 100.

By mixing the low-viscosity polysiloxane and the high-viscosity polysiloxane in the above range and using it as the base resin of the high heat radiation material, it can have sufficient flowability in manufacturing a high heat radiation material by filling a high heat radiation filler, and at the same time the heat resistance of the polysiloxane It is preferable because excellent physical properties such as durability can be maintained.

In addition, at least one or more selected from low viscosity polysiloxane and high viscosity polysiloxane in the polysiloxane mixture may include at least one vinyl-based polysiloxane. For example, it may be a mixture of low viscosity vinyl-based polysiloxane and high viscosity polysiloxane, or a mixture of low viscosity polysiloxane and high viscosity vinyl-based polysiloxane, and the reactivity and fluidity may be adjusted according to the viscosity of the polysiloxane to which the vinyl group is bound, and thus not limited to any one embodiment. Does not.

By including vinyl-based polysiloxane in the polysiloxane mixture can exhibit sufficient adhesive strength with the adherend, specifically, the vinyl-based polysiloxane of the present invention may be a vinyl-based polysiloxane having a polydimethylsiloxane as a main chain, and more specifically Polysiloxane consisting of vinyl groups at both ends may be exemplified as non-limiting examples, but is not limited thereto.

[Formula 1]

(In Formula 1, n is an integer selected from 30 to 300.)

In an aspect of the present invention, the acrylic polysiloxane is included to evenly disperse the heat dissipation filler, and may have a weight average molecular weight of 1,000 to 50,000 g / mol, specifically 2,000 to 25,000 g / mol, but this is only one example. It is not limited to the scope.

The acrylic polysiloxane content in the high heat dissipation liquid silicone composition may be used in an amount of 0.1 to 5 wt%, specifically 0.2 to 3 wt%, more specifically 0.3 to 2 wt%, but is not limited thereto.

Acrylic polysiloxanes in the above ranges are effective in uniformly giving thermal conductivity by improving the dispersibility of the heat dissipating filler in the polysiloxane base resin, and remarkably improving the thermal conductivity of the high heat dissipating material. Specifically, by using the acrylic polysiloxane in the content range, it is possible to prepare a composition excellent in dispersibility without agglomeration even if the content of the heat dissipation filler is increased, and lowers the increase in viscosity due to the high filling of the filler to reduce the It is very effective in keeping the high heat dissipation composition in the liquid phase.

In one embodiment of the present invention, the epoxy-based alkoxy silane is an adhesive, and has a structure represented by Si (R ¹ ) _n (R ² ) _4-n , wherein R ¹ and R ² are each independently hydrogen, halogen, hydroxy, (C1-C10) alkoxy, substituted or unsubstituted oxirane (C1-C10) alkyl group, (C1-C10) alkyl and (C2-C10) alkenyl, wherein at least one of R ¹ is hydroxy and (C1- C10) alkoxy, any one selected from the group consisting of, at least one of R ² comprises an oxirane (C1-C10) alkyl group, and when the oxirane (C1-C10) alkyl group is substituted -CH ₂ -Can be replaced with any one or more substituents selected from one or more -O-, phenylene (-C6H4-) and (C1-C6) alkyl substituted phenylene (-C6H4-), n is an integer from 1 to 3 to be.

The epoxy alkoxy silane content in the high heat dissipation liquid silicone composition may be used in an amount of 0.1 to 10% by weight, specifically 0.4 to 8% by weight, more specifically 0.6 to 6% by weight, but is not limited thereto.

Epoxy-based alkoxy silane in the above content range can impart excellent adhesion even in a high content of the heat-dissipating filler in the high heat dissipation composition, specifically, it can achieve high adhesion in long-term adhesion and high temperature and high humidity conditions.

In one aspect of the invention the heat dissipation filler may be a mixture of boron nitride and metal oxide, the heat dissipation filler content in the high heat dissipation liquid silicone composition is 75 to 95% by weight, specifically 80 to 94% by weight, more specifically 85 to 92 weight percent. It is particularly preferable in that the high heat dissipation filler as described above is included in the composition, so that excellent heat dissipation characteristics of 3.0 W / m · K or more can be realized.

The metal oxide may be any one or a mixture of two or more selected from high heat-dissipating particles such as alumina, magnesium oxide, zinc oxide, and silicon oxide, and the heat dissipation filler mixture may have better thermal conductivity than when boron nitride or metal oxide is used alone. Degree can be expressed.

In this case, the boron nitride and metal oxide may be in the shape of a plate, flake, spherical, elliptical, etc., but is not limited thereto. Preferably, the spherical boron nitride and the spherical metal oxide may be used as a heat dissipation filler to maximize thermal conductivity.

Spherical boron nitride may have an average particle diameter of 0.1 to 100 μm, specifically 0.5 to 80 μm, more specifically 1 to 50 μm. In the present invention, the average particle diameter is a value of D _50, which is a particle size corresponding to 50% of the total volume when the volume is accumulated from small particles by measuring the particle diameter of each spherical particle. Spherical boron nitride having an average particle diameter in the above range can be uniformly distributed in the high heat dissipating composition by being filled between the spherical metal oxide, it is preferable because it can maintain the adhesive force.

In one aspect of the present invention, the metal oxide may be spherical alumina having an average particle diameter of 0.5 to 200 μm, and specifically, may be one having an average particle diameter of 1 to 150 μm, but is not limited thereto. Spherical alumina having an average particle diameter in the above range is preferable because it can be uniformly dispersed in a high heat dissipating composition to exhibit high thermal conductivity. In addition, when used in combination with a spherical boron nitride, the boron nitride particles are filled in the space between the alumina particles, there is an advantage that can be manufactured with a compact heat-resistant filler. This is very effective in increasing the thermal conductivity by increasing the contact surface between the boron nitride and alumina particles.

In one aspect of the invention the spherical alumina may be characterized in that the particle size distribution is trimodal (trimodal). When the spherical alumina of one another and the particle size distribution of the tree modal having three different average particle diameter of the sphere free space of phrases generated alumina cubes having the maximum average particle diameter (D ₁₎ having the following maximum average particle diameter (D ₂₎ Alumina Finally, the alumina particles of the sphere having the smallest average particle diameter (D ₃ ) can fill the remaining space of the cube. This structure not only increases the contact surface between the spherical boron nitride and alumina particles, but also has the effect of further improving thermal conductivity by increasing the contact surface between the spherical aluminas.

In one embodiment of the present invention, the particle size distribution of the spherical alumina may satisfy the following Equations 1 and 2 below.

1.1 <D ₁ / D ₂ <10

10.1 <D ₁ / D ₃ <30

(Wherein D ₁ , D ₂ and D ₃ are the average particle diameters of the different aluminas, respectively.)

In the above formula, D ₁ may be 70 to 200 μm, specifically 80 to 180 μm, D ₁ / D ₂ may be specifically 1.2 to 8, D ₁ / D ₃ may be specifically 12 to 25 have.

Spherical alumina having a trimodal particle size distribution satisfying Equation 1 and 2 can be produced in a compact form by minimizing the empty space of the cube generated from the alumina particles. Accordingly, the volume of the heat dissipation filler in the high heat dissipation composition can be minimized, and at the same time, the contact surface between the alumina particles can be increased to further improve the thermal conductivity.

The high heat dissipation liquid silicone composition of the present invention can provide a uniform and compact heat dissipation filler by using the spherical boron nitride and spherical alumina having a trimodal particle size distribution, and maximize the interfacial contact surface of all the heat dissipation fillers. While sufficient heat transfer passage can be secured, the thermal conductivity can be significantly improved.

When using a high heat dissipation liquid silicone composition in one aspect of the present invention as the component and content range, the viscosity according to ASTM D1084 may be 15,000 cP or less. Specifically, the viscosity may satisfy the physical properties of 1,000 to 15,000 cP, more specifically 5,000 to 14,000 cP. The high heat dissipation liquid silicone composition having a viscosity in the above range has the advantage that it can be used by potting inside an electronic device including a heating element as a high heat dissipation material having a low viscosity, and specifically, high heat dissipation inside a heat generating device such as an electric vehicle OBC. It can be used as a molding material.

That is, the high heat dissipation liquid silicone composition of the present invention includes a polysiloxane, an acrylic polysiloxane, an epoxy alkoxy silane, and a heat dissipation filler, thereby causing a viscosity increase problem caused by a high-filled heat dissipation filler for improving thermal conductivity, which is a problem of conventional silicone heat dissipation materials. In order to solve the problem, it is possible to have high thermal conductivity at the same time due to the low viscosity and high filling heat dissipation filler.

In particular, the silicone material having a low viscosity enough to be potable as a high heat radiation material was absent, but the liquid silicone composition of the present invention is applicable to various fields such as heat dissipation grease, heat dissipation adhesive, as well as electronic components requiring heat dissipation molding. There is this.

In one aspect of the present invention, the high heat dissipation liquid silicone composition may be cured to produce a high heat dissipation molded article. Since the curing reaction may use a curing reaction known in the art, examples of specific reaction additives, curing conditions, and catalysts are omitted.

In one aspect of the present invention, a method for producing a high heat dissipation molded article may be to uniformly mix the high heat dissipation liquid silicone composition and to harden it under a conventional catalyst and a crosslinking agent.

Specifically, for example, a polysiloxane, an acrylic polysiloxane, an epoxy alkoxy silane, a catalyst and a crosslinking agent are mixed in a stirrer at a constant temperature to prepare a base composition. Next, a heat dissipation filter including spherical boron nitride and alumina particles is introduced into the stirrer for a predetermined time from small to large in order to prepare a uniform high heat dissipation liquid silicone composition. Next, the composition may be placed in a mold and pressure molded at a high temperature to produce a high heat dissipation molded article.

In the production method, the base composition manufacturing step may be carried out at 20 to 60 ℃ 10 minutes to 1 hour, specifically 30 to 50 ℃ 20 to 40 minutes. In addition, the step of producing a high heat dissipation liquid silicone composition may be carried out for 30 minutes to 2 hours at 30 to 80 ℃, specifically 30 minutes to 1 hour at 30 to 60 ℃. The manufacturing step of the high heat-dissipating molded article may be prepared by pressure molding at 80 to 230 ° C. for 1 to 50 minutes, specifically at 100 to 180 ° C. for 10 to 30 minutes, but is not limited thereto.

Through the manufacturing method, it is possible to manufacture a high heat-dissipating molded article having excellent thermal conductivity without causing agglomeration between particles of high heat-dissipating filler particles.

In one embodiment of the present invention, the high heat-dissipating molded article may have an elongation of 20% or more according to ASTM D412. Specifically, the elongation may be 20 to 50%, more specifically 22 to 35%, but is not limited thereto. The molded article of the present invention has an elongation in the above range, can be applied as a heat dissipation material of electronic products requiring flexibility, and can be used for a long time without breaking.

In one aspect of the present invention, the high heat dissipation molded article may have a thermal conductivity of 3.0 W / m · k or more according to ASTM E1461. Specifically, the thermal conductivity may be 3.1 to 10.0 W / m · k, more specifically, 3.2 to 7.0 W / m · k, but is not limited thereto.

The molded article of the present invention has a thermal conductivity in the above range, thereby significantly reducing the temperature inside the heating element, thereby preventing the shortening of the life due to the deterioration of the electronic component function due to heat generation.

In particular, as a heat dissipation material to cancel the heat generation significantly increased with the miniaturization and high density of electronic components, there is an advantage that can be extended to the part that requires heat dissipation molding, including reactor parts of the electric vehicle.

In one aspect of the present invention, the high heat dissipation molded article may have an adhesive strength of 50 Kgf / cm ^{2 or} more according to ASTM D816. Specifically, the adhesive strength may be 50 to 1,500 Kgf / cm ² , more specifically 100 to 1,000 Kgf / cm ² . The molded article of the present invention can reduce the peeling of the radiator from the heating element that can be generated in the environment of high temperature, high humidity by having the adhesive strength in the above range. In addition, the high heat-dissipating molded article according to the present invention has excellent heat resistance and durability of silicon as it includes silicon, and thus is easily adhered to the surface of the electronic component, thereby enabling long-term use.

In an aspect of the present invention, a sealed automotive part may be manufactured using the high heat dissipation liquid silicone composition. The high heat dissipation liquid silicone composition according to the present invention overcomes the limitations of the conventional heat dissipation material, which is difficult to be applied to miniaturized electronic products, and is used as a potting material that is used in a form bonded to a component by pouring the composition into a heat generating device of a vehicle. It is possible. In addition, the automotive parts sealed with the potting material according to the present invention has excellent heat generating function, heat resistance and long-term reliability.

In one embodiment of the present invention, the high heat dissipation liquid silicone composition is a heating element embedded in an electric component such as a high power LED chip, a semiconductor chip, a plastic substrate, a computer, a plasma display panel, etc. that require high thermal conductivity as well as automobile parts. Applicable to the part material.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following Examples and Comparative Examples are only examples for explaining the present invention in more detail, the present invention is not limited by the following Examples and Comparative Examples.

Hereinafter, physical properties were measured by the following method.

1) viscosity (cP)

 Viscosity was measured according to ASTM D1084.

2) elongation (%)

 Elongation was measured according to ASTM D412.

3) Thermal Conductivity (W / mK)

 Thermal conductivity was measured according to ASTM E1461.

4) Adhesive Strength (Kgf / cm ² )

 Adhesion strength was measured according to ASTM D816.

5) Long-term high temperature stability test

 The long-term high temperature stability test was measured according to AEC-Q200, Method 108, and crack generation was confirmed by exposing 300 cycles of 1 cycle of -40 to 125 ° C.

Example 1-5

After mixing the components shown in Table 1 using a mixer (DISSOLVER, Thiele Technologies, Vacuum Planetary mixer 10) for 1 hour at 40 ℃, Karstedt's Catalyst-2% (Herius, containing 2% by weight of platinum) 0.1 wt% was added and kneaded for 30 minutes to prepare a high heat dissipation liquid silicone composition, and the viscosity of the composition is shown in Table 2.

In addition, the high heat-dissipating liquid silicone composition was press-molded at 130 ° C. for 10 minutes to prepare a test specimen having a size of 150 × 150 mm, and the measured physical properties are shown in Table 2 below.

The units of the components in Table 1 below are in weight percent, and the polysiloxanes used are U-01 and U-1 products of H & S Co., Ltd., each having a viscosity of 100 cP and 1,000 cP. In addition, BASF's EFKA® 4330 was used as the acrylic polysiloxane, and Momentive's A-187 was used as the epoxy-based alkoxy silane. As boron nitride, NW-04 (particle diameter: 5 μm) manufactured by National nitride Tech. Was used, and spherical alumina manufactured by Denka Corporation was used as alumina.

Comparative Example 1

Except for using 89% by weight of only alumina particles having an average particle diameter of 50μm as a heat dissipation filler was carried out in the same manner as in Example 1, the measured physical properties are shown in Table 2.

Comparative Example 2

Except for using 89% by weight of only alumina particles having an average particle diameter of 7μm as a heat dissipation filler was carried out in the same manner as in Example 1, the measured physical properties are shown in Table 2.

U-01 U-1 EFKA®
4330 A-187 NW-04 Alumina
(Particle diameter: 7μm) Alumina
(Particle diameter: 50μm) Alumina
(Particle diameter: 90μm) Example 1 9.4 - 0.5 One 5 - 84 - Example 2 8 1.4 0.5 One 5 42 - 42 Example 3 8 1.4 0.5 One 5 42 42 - Example 4 8 1.4 0.5 One 5 - 42 42 Example 5 8 1.4 0.5 One 5 28 28 28

Viscosity Elongation Thermal conductivity Adhesive strength Long term high temperature stability Example 1 14,000 20 3.001 750 No cracks Example 2 13,900 25 3.162 761 No cracks Example 3 13,200 24 3.067 784 No cracks Example 4 13,600 22 3.114 755 No cracks Example 5 12,500 27 3.255 795 No cracks Comparative Example 1 20,200 9 2.250 765 Crack Comparative Example 2 21,000 12 2.043 759 Crack

As shown in Table 2, Example 1-5 according to the present invention has a viscosity of less than 15,000 cP according to ASTM D1084, the thermal conductivity according to the method of ASTM E1461 is 3.0 W / mK or more, ASTM D816 Adhesion strength is 50 Kgf / cm ² or more.

Specifically, in the case of Example 5 using the low viscosity and high viscosity polysiloxane mixture and alumina that may have a trimodal particle size distribution characteristics, it was confirmed that the lowest viscosity and excellent thermal conductivity.

Therefore, the high heat dissipation liquid silicone composition according to the present invention can be used as a heat dissipation molding material by easily potting the inside of an electronic product by showing a low viscosity and high thermal conductivity at the same time. In addition, it has been confirmed that the elongation and adhesive strength can be applied as a flexible heat dissipation material and can be easily attached to electronic components.

  However, as can be seen from the comparative example, when the composition of the present invention deviated from the high viscosity silicone heat-dissipating material is impossible to port, thermal conductivity was inferior and long-term high temperature stability was confirmed to be poor.

Claims (13)

Polysiloxanes, acrylic polysiloxanes, epoxy-based alkoxy silanes and heat dissipating fillers, wherein the polysiloxanes are composed of low viscosity polysiloxanes having a viscosity of 30 to 500 cP measured at 25 ° C. and high viscosity polysiloxanes having a viscosity of 500 to 10,000 cP measured at 25 ° C. A mixture, the mixture comprising at least one vinyl-based polysiloxane,
The heat dissipation filler includes a spherical alumina having an average particle diameter of 0.5 to 200 μm, the spherical alumina has a trimodal distribution of particle size distribution,
High heat dissipation liquid silicone composition having a viscosity of 15,000 cP or less according to ASTM D1084. delete The method of claim 1,
The heat dissipation filler is a high heat dissipation liquid silicone composition is a mixture of boron nitride and spherical alumina. delete delete The method of claim 1,
The particle size distribution is a high heat dissipation liquid silicone composition that satisfies the formulas 1 and 2.
1.1 <D ₁ / D ₂ <10
10.1 <D ₁ / D ₃ <30
(Wherein, D ₁ , D _2, and D ₃ are the average particle diameters of each of the three aluminas having different average particle diameters.) The method of claim 1,
The high heat dissipation liquid silicone composition is a high heat dissipation liquid silicone composition comprising 1 to 20% by weight polysiloxane, 0.1 to 5% by weight acrylic polysiloxane, 0.1 to 10% by weight epoxy-based alkoxy silane and 75 to 95% by weight heat dissipation filler. delete A high heat dissipation molded article prepared by curing the high heat dissipation liquid silicone composition of any one of claims 1, 3, 6 and 7. The method of claim 9,
The molded article is a high heat-resistant molded article having an elongation of 20% or more according to ASTM D412. The method of claim 9,
The molded article is a high heat radiation molded article having a thermal conductivity of 3.0 W / m · k or more according to ASTM E1461. The method of claim 9,
The molded article is a high heat-resistant molded article having an adhesive strength of 50Kgf / cm ² or more according to ASTM D816. An automotive part sealed using the high heat dissipation liquid silicone composition of any one of claims 1, 3, 6 and 7.