KR20220161897A - Two-component heat dissipation gap filler composition using silicone - Google Patents

Abstract

The present invention relates to a two-component heat dissipation gap filler composition using silicone, comprising: a main agent comprising a filler selected from a silicone polymer having a vinyl group, aluminum hydroxide or alumina, or a mixture thereof, a catalyst, and an anti-settling agent; and a cross-linking agent including a filler selected from a silicone polymer having an H group, aluminum hydroxide or alumina, or a mixture thereof, and an anti-settling agent. The composition improves dispersibility and lowers density to be applied directly to a site where heat dissipation is required while enabling the application to irregular or very narrow spaces, thereby improving the heat dissipation effect.

Description

Two-component heat dissipation gap filler composition using silicone {Two-component heat dissipation gap filler composition using silicone}

The present invention relates to a two-component heat-dissipating gap filler composition using silicone, and more particularly, improves dispersibility and lowers density so that it can be directly applied on the spot where heat dissipation is required, and can be applied even in irregular or very narrow spaces. It relates to a two-component heat dissipation gap filler composition using silicone to improve the heat dissipation effect.

As electric and electronic devices are becoming smaller and thinner, excellent heat dissipation effects are required. However, due to the small size and ultra-thinness, it is not possible to secure sufficient space for installing the heat radiating fins, which reduces the heat generating area of the heat radiating fins, which causes malfunctions due to overheating. In severe cases, there is a problem in that an explosion or a fire occurs in the device.

That is, elements used in electrical and electronic devices generate heat while power is supplied, and this heat must be quickly dissipated to the outside through a heat sink and heat sink fins. Since sufficient space is not secured to install the lamp, the generated heat stays inside the housing of the device and continuously heats up, eventually causing problems such as malfunction.

In addition, in order to solve problems such as environmental pollution, the demand for electric vehicles that reduce carbon emissions is increasing recently. A pack is used, and heat dissipation characteristics are very important because there is a difference in the performance of an electric product depending on the cooling performance of the battery cell.

However, since a plurality of batteries are arranged in the above battery cells, heat dissipation in the space between the batteries is very important. However, when the space between the batteries is narrow or non-square, such as when a circular battery is used, it is very difficult to install a heat sink or the like between them. There was a problem that the heat dissipation effect could not be obtained.

Accordingly, as a prior art for improving the heat dissipation performance of battery cells, Korean Patent Publication No. 10-2019-0064209 includes 100 parts by weight of non-conductive oil, 1 to 30 parts by weight of thermally conductive inorganic particles, and 1 to 30 parts by weight of an inorganic anti-settling agent. However, the viscosity at 20 ℃ is 850 cP or more, and the viscosity at 30 ℃ is 750 cP or less, and a heat dissipation fluid composition used by filling the inside of a module case filled with a battery is proposed.

At this time, the thermally conductive inorganic particles exhibiting a heat dissipation effect include silica (but, fumed silica is excluded), alumina (but, fumed alumina is excluded), aluminosilicate, aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), and It may be at least one selected from the group consisting of boron nitride (BN).

In the conventional heat-dissipating fluid composition having such a configuration, inorganic particles having good thermal conductivity are added to the heat-dissipating fluid, in which the viscosity rapidly decreases and behaves like a liquid when heat is generated by discharge, and the viscosity rapidly increases and behaves like a solid during the rest period when charging and discharging do not occur. It is dispersed so that precipitation of inorganic particles does not occur, maintaining excellent heat dissipation characteristics.

However, in the prior art, since the heat dissipation fluid composition is filled and sealed inside a module case into which batteries are inserted, the module case must be completely sealed, but when the sealed state is released or the case is damaged during use, the liquid heat dissipation fluid composition It flows down and cannot achieve a sufficient heat dissipation effect, which causes abnormalities in the performance of the vehicle or, in severe cases, a fire.

In addition, it is said that the viscosity decreases during heat generation and behaves like a liquid phase. However, if vibration or stirring is not accompanied, the inorganic particles eventually settle, so not only does not uniform heat dissipation occur, but sufficient heat is not achieved in the part where the distribution of inorganic particles is small. There was a problem that didn't work.

An object of the present invention for solving the above problems is to reduce the amount of filler used per unit volume by improving the contact area with the heating element while having a low density, and to obtain an excellent heat dissipation effect, and after coating the liquid on the heating element in a two-component type, An object of the present invention is to provide a two-component heat dissipation gap filler composition using silicone, which is easily cured and can be coated even in atypical and minute gaps between electronic parts to obtain an excellent heat dissipation effect.

In addition, the fillers are mixed with different diameters to improve the contact area with the heating element, and the filler is coated with fatty acid to improve the dispersibility in silicone to uniformly contact the heating element. Provide a two-component heat dissipation gap filler composition using silicone has a purpose to

A feature of the present invention for achieving the above object is a subject comprising a filler, a catalyst and an anti-settling agent selected from a silicone polymer having a vinyl group, aluminum hydroxide or alumina or a mixture thereof; A cross-linking agent comprising a filler selected from H group-containing silicone polymer, aluminum hydroxide or alumina or a mixture thereof, and an anti-settling agent; It is in a two-component heat dissipation gap filler composition using silicone comprising a.

In the above, fillers having different diameters are mixed and used.

In addition, the filler is coated with a fatty acid to improve dispersibility in silicone.

According to the present invention configured as described above, the contact area with the heating element is improved while the density is low, so there is an effect of reducing the amount of filler used per unit volume and obtaining an excellent heat dissipation effect.

In addition, since it is a two-component type, it can be mixed on-site, coated in liquid form on the heating element, and then cured quickly and easily, so that it is possible to coat even irregular gaps and fine gaps between electronic parts, so that excellent heat dissipation effects can be obtained.

Hereinafter, an embodiment of the present invention will be described.

The two-component heat-dissipating gap filler composition using silicone according to the present invention includes a silicone polymer having a vinyl group, aluminum hydroxide or alumina, or a filler composed of a mixture thereof, a catalyst, and an anti-settling agent; A cross-linking agent comprising a filler selected from H group-containing silicone polymer, aluminum hydroxide or alumina or a mixture thereof, and an anti-settling agent; It is composed of.

Aluminum hydroxide and alumina constituting the filler are mixed and used at a weight ratio of 1: 0 to 0.5, because aluminum hydroxide has a lower density than alumina, so that the amount used per unit volume can be reduced and costs can be reduced.

At this time, fillers of different diameters are mixed and used. For example, aluminum hydroxide is mixed and used with diameters of 40-60㎛, 20-40㎛, 5-20㎛, 1-10㎛, and 0.1-1㎛. Properly improves the heat dissipation effect by improving the contact area between the conductive filler and the heating element.

An example of the use of aluminum hydroxide is 20-40% by weight of aluminum hydroxide having a diameter of 40-60㎛ based on the total weight of the filler used in the main body, 10-30% by weight of aluminum hydroxide having a diameter of 20-40㎛, and aluminum hydroxide 20 having a diameter of 5-20㎛ -40 wt%, 1-10 μm aluminum hydroxide 10-30 wt%, 0.1-1 μm aluminum hydroxide 10-20 wt% is used.

And in the case of alumina, a slightly smaller diameter than the aluminum hydroxide is used. Specifically, alumina having a diameter of 15-30 μm is 20-40% by weight based on the total weight of the filler, and alumina having a diameter of 1-15 μm is 40 based on the total weight of the filler. -60% by weight, 0.1-1㎛ alumina is used by mixing 10-20% by weight based on the total weight of the filler.

In the above, the alumina of 1-15 μm is again divided into 8-15 μm, 6-8 μm, and 1-6 μm, and the amount used is 5-30% by weight, respectively, based on the total weight of the filler.

On the other hand, looking at the reason why alumina having a smaller diameter than aluminum hydroxide is used, silicon floats to the top due to the density difference between silicon and filler, which is called oil separation.

This oil separation becomes more severe as the viscosity of the entire heat dissipation gap filler is low and the density of the filler is high. Since alumina has a higher density than aluminum hydroxide, sedimentation occurs more quickly, which is disadvantageous in terms of oil separation.

Therefore, when alumina is used, oil separation is minimized by reducing the sedimentation rate by lowering the particle size than aluminum hydroxide.

Second, the particle size is changed to make the thermal conductivity similar.

That is, since aluminum hydroxide has lower thermal conductivity than alumina, aluminum hydroxide with a relatively large particle size is used to increase thermal conductivity, and similar thermal conductivity can be obtained even when alumina uses a filler with a smaller diameter than aluminum hydroxide. because there is

In addition, the filler is coated with a fatty acid to improve dispersibility in silicone.

At this time, the fatty acids include Caprylic acid, Capric acid, Lauric acid, Myristic acid, Palmitic acid, and Stearic acid. Use one or at least one mixture selected from the group consisting of, and use 0.01 to 0.03 wt% based on the weight of the filler.

As an example of the fatty acid coating, 1 L of ethanol and 300 g of filler were added to the stirring tank, stirred for 30 minutes, then 0.3 g of fatty acid was added and further stirred for 30 minutes. When the stirring was completed, the filler was filtered using a filter, and 500 cc of ethanol Wash the filler with

After washing is completed, the filler is recovered and dried for 3 hours at 100 ° C open.

The dried filler is pulverized with an air jet mill to complete the fatty acid coating of the filler.

As the catalyst, 0.05 to 0.5 wt% of a platinum catalyst is used based on 100 wt% of the total weight of the main composition.

In the present invention configured as described above, the main agent and the crosslinking agent are mixed and used in a ratio of 1:1, and cured at room temperature or elevated temperature conditions.

Let's look at these embodiments of the present invention.

Example 1)

The two-component heat-dissipating gap filler composition using silicone according to the present invention was introduced into a planetary mixer at a ratio of 9.8 wt% of the liquid organopolysiloxane containing a vinyl group, 0.1 wt% of the platinum catalyst, 90 wt% of the filler, and 0.1 wt% of the anti-settling agent, and 1 After stirring for an hour, a silicone addition-type main composition was prepared by dispersing three times using a 3 roll mill.

At this time, the filler was 25 wt% of aluminum hydroxide having a size of 50 μm, 20 wt% of aluminum hydroxide having a size of 30 μm, 10 wt% aluminum hydroxide having a size of 10 μm, 20 wt% aluminum hydroxide having a size of 5 μm, and 20 wt% aluminum hydroxide having a size of 0.5 μm, based on the total weight of the main material. of aluminum hydroxide in an amount of 15 wt%.

In addition, 9.9 wt% of Si-H group-containing organohydrogenpolysiloxane, 90 wt% of filler, and 0.1 wt% of antisettling agent were put into a planetary mixer, stirred for 1 hour, and then dispersed three times using a 3 roll mill to form silicone. An addition-type crosslinking agent composition was prepared.

In the above filler, based on the total weight of the crosslinking agent, 25 wt% of aluminum hydroxide having a size of 50 μm, 20 wt% of aluminum hydroxide having a size of 30 μm, 10 wt% aluminum hydroxide having a size of 10 μm, 20 wt% aluminum hydroxide having a size of 5 μm, and 0.5 μm It is used in a proportion of 15 wt% of aluminum hydroxide.

Example 2)

The two-component heat-dissipating gap filler composition using silicone according to the present invention was added to a planetary mixer at a ratio of 9.9 wt% of a liquid organopolysiloxane containing a vinyl group, 0.1 wt% of a platinum catalyst, 90 wt% of a filler, and 0.1 wt% of an antisettling agent, and 1 After stirring for an hour, a silicone addition-type main composition was prepared by dispersing three times using a 3 roll mill.

The filler is 25 wt% of alumina having a size of 20 μm, 20 wt% of alumina having a size of 10 μm, 10 wt% of alumina having a size of 7 μm, 20 wt% of alumina having a size of 5 μm, and 15 wt% of alumina having a size of 0.5 μm based on the total weight of the main material used as a percentage.

Then, 10 wt% of Si-H group-containing organohydrogenpolysiloxane, 90 wt% of filler, and 0.1 wt% of antisettling agent were put into a planetary mixer, stirred for 1 hour, and then dispersed three times using a 3 roll mill. A silicone addition crosslinking agent composition was prepared.

At this time, the filler was 35 wt% of 20 μm alumina, 20 wt% of 10 μm alumina, 10 wt% of 7 μm alumina, 20 wt% of 5 μm alumina, and 15 wt% of 0.5 μm alumina based on the total weight of the crosslinking agent. used as a percentage.

The thermal conductivity, density, viscosity and hardness test results of Examples 1 and 2 are shown in Table 1 below.

division Thermal conductivity (W/mK) ^A Density (g/cc) ^B Viscosity (Pa.S) ^C Shore A ^D Example 1 2.3 2.0 120 20 Example 2 2.2 2.8 130 35

In the above, A) thermal conductivity was measured using the TPS-500S (Hot Disk Co.) isotropic method at a sample temperature of 25 ° C. and a heating power of 200 mW.

B) Density cup The density of the sample was measured at 25 ° C using a 50 cc density cup.

Density of sample (g/cc) = (weight of density cup containing sample - weight of density cup)/50

C) The viscosity of the prepared liquid gap filler was stored at 25 ° C for 1 month, and then the viscosity of the sample was measured using a Brookfield DV II + Pro viscometer at spindle # 6, 20 rpm, 25 ° C.

D) Shor A hardness is measured by mixing 100 g of liquid gap filler agent A and 100 g of agent B to make a specimen with a width of 50 mm, length of 50 mm, and thickness of 10 mm, curing in an oven at 80 ° C for 30 minutes, and then using a Shore A hardness tester. The hardness of the specimen was measured.

As shown in Table 1, the two-component heat dissipation gap filler composition using silicone according to the present invention has excellent thermal conductivity and low viscosity, and excellent fluidity, and the example using aluminum hydroxide as a filler has a lower density than the comparative example. was able to confirm

Claims (5)

A subject comprising a filler selected from a silicone polymer having a vinyl group, aluminum hydroxide, or alumina, or a mixture thereof, a catalyst, and an antisettling agent;
A cross-linking agent comprising an H group-containing silicone polymer, aluminum hydroxide, or alumina, or a filler composed of a mixture thereof, and an anti-settling agent;
A two-component heat dissipation gap filler composition using silicone, characterized in that it comprises a. The two-component heat-dissipating gap filler composition using silicone according to claim 1, wherein the fillers used in the main agent and the crosslinking agent are mixed with different diameters. The method of claim 2, wherein when aluminum hydroxide is used as the filler, it is characterized in that it is mixed and used with a diameter of 40-60 μm, 20-40 μm, 5-20 μm, 1-10 μm, and 0.1-1 μm. A two-component heat dissipation gap filler composition using silicone to The two-component heat dissipation gap filler composition using silicon according to claim 2, wherein, when alumina is used as the filler, a filler having a diameter of 15-30 μm, 1-15 μm, and 0.1-1 μm is mixed and used. The two-component heat dissipation gap filler composition using silicone according to any one of claims 1 to 4, wherein the filler is coated with a fatty acid before use.