阅读说明：本技术 具有提高热导率的轻质聚合物组合物，其制备方法和使用其的产品 (Lightweight polymer composition with enhanced thermal conductivity, method of making the same and products using the same ) 是由 金智恩 全祥寿 金圣勋 于 2018-11-14 设计创作，主要内容包括：本发明公开了具有优异热导率的轻质聚合物组合物,其制备方法和使用其的产品,具体公开了一种用于散热垫的组合物,例如,用于诸如电动车辆的车辆中的水冷型电池组的冷却系统中的散热片。散热垫可以散发从电池组中产生的热量。还公开了一种制造具有高热导率和低比重的散热垫的方法。所述组合物可包括聚合物组合物,所述聚合物组合物包括碳纤维、氢氧化铝和中空玻璃珠。(Disclosed are a lightweight polymer composition having excellent thermal conductivity, a method for preparing the same, and a product using the same, and particularly, a composition for a heat-dissipating pad, for example, a heat sink used in a cooling system of a water-cooled battery pack in a vehicle such as an electric vehicle. The heat dissipation pad may dissipate heat generated from the battery pack. A method of manufacturing a thermal pad having high thermal conductivity and low specific gravity is also disclosed. The composition may include a polymer composition including carbon fibers, aluminum hydroxide, and hollow glass beads.)

1. A polymer composition comprising:

100 parts by weight of a siloxane-based resin;

20 to 50 parts by weight of carbon fibers;

100 to 200 parts by weight of an inorganic filler; and

20 to 50 parts by weight of hollow glass beads,

All parts by weight are based on 100 parts by weight of the siloxane-based resin.

2. The polymer composition of claim 1, wherein the siloxane-based resin comprises:

A first siloxane-based resin comprising a first polysiloxane having one or more vinyl groups at both ends; and

A second siloxane-based resin comprising a second polysiloxane having one or more vinyl groups at both ends and a third polysiloxane having Si-H bonds.

3. the polymer composition of claim 2, wherein the first polysiloxane or the second polysiloxane is of formula 1:

[ chemical formula 1]

Wherein n is an integer of 100 to 200, and

Wherein the third polysiloxane has a structure of chemical formula 2:

[ chemical formula 2]

Wherein n' is an integer of 1 to 100 and m is an integer of 1 to 100.

4. The polymer composition of claim 2, wherein the first siloxane-based resin further comprises a platinum catalyst, and

The second siloxane-based resin further comprises a retarder comprising formula

the compound of (1).

5. The polymer composition according to claim 1, wherein the carbon fibers have a diameter of 5 to 15 μ ι η.

6. The polymer composition according to claim 1, wherein the carbon fibers have a length of 50 to 250 μ ι η.

7. The polymer composition of claim 1, wherein the carbon fiber has a thermal conductivity of 500W/mK to 900W/mK.

8. The polymer composition of claim 1, wherein the carbon fiber has a density of 2.00g/cm³to 2.40g/cm³。

9. The polymer composition according to claim 1, wherein the inorganic filler is aluminum hydroxide having a diameter of 1 to 100 μm, aluminum oxide having a diameter of 2 to 150 μm, and a mixture thereof.

10. The polymer composition of claim 1, wherein the hollow glass bead has a density of 0.2g/cm³to 0.8g/cm³。

11. The polymer composition of claim 1, wherein the hollow glass beads have a thermal conductivity of 0.1W/mK to 0.2W/mK.

12. The polymer composition of claim 1, wherein the hollow glass beads have a diameter of 35 μ ι η to 45 μ ι η.

13. A thermal pad comprising the thermally conductive polymer composition of claim 1.

14. The thermal pad of claim 13, wherein the thermal pad has a thermal conductivity of 1.5W/mK to 5.0W/mK and/or a specific gravity of 1.1 to 1.5.

15. A method of manufacturing a thermal pad, the method comprising:

preparing mixture A by mixing a first siloxane-based resin with carbon fibers, the first siloxane-based resin including a first polysiloxane having one or more vinyl groups at both ends;

Preparing a mixture B by mixing a second siloxane-based resin with hollow glass beads, the second siloxane-based resin including a second polysiloxane having one or more vinyl groups at both ends and a third polysiloxane having one or more Si-H bonds at both ends;

Obtaining a thermally conductive polymer composition by mixing the mixture a, the mixture B, and an inorganic filler; and

The thermally conductive polymer composition is formed into a predetermined shape of a thermal pad and then cured.

16. the method of fabricating a thermal pad according to claim 15, wherein the carbon fibers have a diameter of 5 to 15 μ ι η, a length of 50 to 250 μ ι η, a thermal conductivity of 500 to 900W/mK, and/or a density of 2.00g/cm³To 2.40g/cm³。

17. The method for fabricating a thermal pad according to claim 15, wherein the hollow glass beads have a density of 0.2g/cm³To 0.8g/cm³the thermal conductivity is 0.1W/mK to 0.2W/mK, and/or the diameter is 35 μm to 45 μm.

18. The method of fabricating a thermal pad according to claim 15, further comprising applying the polymer composition to a substrate to form a predetermined shape of a sheet or web.

19. The method for fabricating a thermal pad according to claim 15 wherein the temperature for curing ranges from room temperature to 200 ℃.

20. a vehicle comprising the thermal pad of claim 13.

Technical Field

the present invention relates to a polymer composition for a vehicle thermal pad that can be disposed in a cooling system of a vehicle to dissipate heat.

Background

conventional heat sinks are made by adding a liquid polymer binder (e.g., a thermosetting silicone gel or an ultraviolet cured acrylic) and a thermally conductive ceramic filler (e.g., alumina (Al)₂O₃) Aluminum hydroxide (Al)₃(OH)₂) Aluminum nitride (ain), Boron Nitride (BN), silicon carbide, etc.).

Although a heat sink fabricated by adding a liquid polymer binder with at least one thermally conductive ceramic filler listed above may improve the thermal conductivity of the product due to the high specific gravity (e.g., 2.4 or more) of the filler material, the weight of the product may not be sufficiently reduced.

Therefore, there is a need for materials having a low specific gravity that can help reduce the size and weight of products in many fields.

Disclosure of Invention

Detailed Description

The above and other aspects, features and advantages of the present invention will be more clearly understood through the following preferred embodiments. However, the present invention is not limited to the embodiments described herein, and may be modified into different forms. These embodiments are provided so that this disclosure will be thorough and will fully convey the spirit of the invention to those skilled in the art.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "has," "having," and the like, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element such as a layer, film, region, or substrate is referred to as being "under" another element, it can be directly under the other element or intervening elements may be present therebetween.

Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally includes motor vehicles such as passenger automobiles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats, ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-petroleum sources). As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as both gasoline-powered and electric-powered vehicles.

Further, unless otherwise indicated or clearly differentiated from the context, the term "about" as used herein is to be understood as being within the ordinary tolerance in the art, e.g., within 2 standard deviations of the mean. "about" can be understood as being within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the stated value. All numerical values provided herein are modified by the term "about" unless the context clearly dictates otherwise.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

the present invention provides a polymer composition or a thermally conductive polymer composition, which may include a silicone-based resin, carbon fibers, an inorganic filler, and hollow glass beads.

The thermally conductive polymer composition may include 100 parts by weight of a siloxane-based resin, about 20 parts by weight to 50 parts by weight of carbon fibers, about 100 parts by weight to 200 parts by weight of an inorganic filler, and about 20 parts by weight to 50 parts by weight of hollow glass beads. All parts by weight are based on 100 parts by weight of the siloxane-based resin.

In the present invention, the siloxane-based resin may include a first siloxane-based resin including a first polysiloxane having one or more vinyl groups at both ends, and a second siloxane-based resin including a second polysiloxane having one or more vinyl groups at both ends and a third polysiloxane having Si-H bonds.

For example, first and second polysiloxanes having one or more vinyl groups at both ends may be represented by the following chemical formula 1, and a third polysiloxane having Si — H bonds may be represented by the following chemical formula 2.

[ chemical formula 1]

Wherein n is an integer from 100 to 200.

[ chemical formula 2]

Wherein n' may be an integer of 1 to 100, and m may be an integer of 1 to 100.

In the present invention, the first siloxane-based resin may further include a platinum catalyst for the addition reaction. The platinum catalyst as used herein can promote curing of the siloxane-based resin, and thus the curing time can be a short time.

The platinum catalyst may be contained in an amount of about 0.10 to 0.20 wt% based on the total weight of the first siloxane-based resin. Accordingly, the content of the polysiloxane of chemical formula 1 may be suitably 99.80 to 99.90% by weight.

In the present invention, the second silicone-based resin may further include a retarder. The retarder may include a compound represented by the following chemical formula 3.

The retarder may be present in an amount of about 0.02 wt% to 0.05 wt% based on the total weight of the second siloxane-based resin. Accordingly, the content of the polysiloxane of chemical formula 1 may be suitably 95 to 99% by weight, and the content of the polysiloxane of chemical formula 2 may be preferably 1 to 5% by weight, based on the total weight of the second siloxane-based resin.

[ chemical formula 3]

In the present invention, the siloxane-based resin (i.e., the first siloxane-based resin and the second siloxane-based resin) may be contained in an amount of about 25 to 50 wt%, preferably about 28 to 40 wt%, based on the total weight of the thermally conductive polymer composition.

Carbon fibers as used herein can improve the thermal conductivity of the composition.

The carbon fibers may have a diameter of about 5 to 15 μm, a length of about 50 to 250 μm, a thermal conductivity of about 500 to 900W/mK, and a density of about 2.00g/cm³to 2.40g/cm³。

Preferably, the carbon fibers may have a density of about 2.00g/cm³To 2.30g/cm³. Further, the length of the carbon fiber may suitably be about 100 to 200 μm, or particularly about 100 to 150 μm. Thus, products made using the compositions of the present invention can have significantly improved thermal conductivity and reduced specific gravity, which is most desirable.

Preferably, the thermal conductivity of the carbon fiber may be about 600W/mK to 700W/mK.

Therefore, when the length of the carbon fiber is less than about 50 μm, a sufficient carbon fiber array may not be formed within the component ratio range of the composition, making it difficult to exhibit desired thermal conductivity. On the other hand, when the length thereof is greater than about 250 μm, uniform dispersion of the material may be difficult due to an increase in viscosity.

The content of the carbon fiber may suitably be about 20 to 50 parts by weight, about 25 to 45 parts by weight, or particularly about 30 to 45 parts by weight, based on 100 parts by weight of the siloxane-based resin.

When the amount of the carbon fibers is less than about 20 parts by weight, the thermal conductivity of the thermally conductive polymer composition may not be sufficiently improved. On the other hand, when the amount thereof is more than about 50 parts by weight, the insulation property of the product obtained using the thermally conductive polymer composition may be deteriorated and the manufacturing cost may be unreasonably increased, thereby offsetting economic benefits.

In the present invention, the inorganic filler may suitably be a thermally conductive inorganic filler, and may be a ceramic filler, such as alumina (Al)₂O₃) Aluminum hydroxide (Al (OH)₃) Aluminum nitride (AlN), Boron Nitride (BN), silicon carbide and mixtures thereof. Preferably, the ceramic filler may include alumina, aluminum hydroxide, and mixtures thereof. For example, the inorganic filler may include or be aluminum hydroxide. When aluminum hydroxide is used, the specific gravity of the thermally conductive polymer composition or a product formed from the thermally conductive polymer composition can be effectively reduced without reducing the thermal conductivity.

Preferably, aluminum hydroxide (Al (OH)₃) May be about 1 to 100 μm in diameter, alumina (Al)₂O₃) May be about 2 to 150 μm in diameter.

The thermally conductive inorganic filler may be contained in an amount of about 100 parts by weight to 200 parts by weight, and about 100 parts by weight to 150 parts by weight, based on 100 parts by weight of the silicone-based resin.

When the amount of the thermally conductive inorganic filler is less than about 100 parts by weight, the amount of the thermally conductive material in the thermally conductive polymer composition may be reduced, and thus, the thermal conductivity may be reduced. On the other hand, when the amount thereof is more than about 200 parts by weight, the relative amount of the hollow glass beads may decrease, and thus the specific gravity of the thermally conductive polymer composition or a product formed of the thermally conductive polymer composition may not be sufficiently decreased, and further, the hardness of the cured product may increase, which is not desirable.

The hollow glass beads used herein can reduce the specific gravity of the product and have a density of about 0.2g/cm³To 0.8g/cm³The thermal conductivity is about 0.1W/mK to 0.2W/mK and the diameter is about 35 μm to 45 μm.

The content of the hollow glass beads may be about 20 to 50 parts by weight, about 25 to 45 parts by weight, or particularly about 30 to 45 parts by weight, based on 100 parts by weight of the siloxane-based resin. When the amount of the hollow glass beads is less than about 20 parts by weight, the specific gravity of the thermally conductive polymer composition may be insufficiently reduced, and the weight of a product formed from the thermally conductive polymer composition may be insufficiently reduced. On the other hand, when the amount thereof is more than about 50 parts by weight, the porosity of a product formed of the thermally conductive polymer composition may increase, thereby reducing the thermal conductivity.

Also provided is a thermal pad comprising the thermally conductive polymer composition.

For example, a thermal pad manufactured by mixing a silicone-based resin, carbon fibers, a thermally conductive inorganic filler, and hollow glass beads in an amount according to an exemplary embodiment of the present invention may have a thermal conductivity of about 1.5W/mK to 5.0W/mK, and a specific weight of about 1.0 to 1.5.

A method of manufacturing a thermal pad is also provided. The method may comprise: preparing mixture A by mixing a first siloxane-based resin with carbon fibers, the first siloxane-based resin including a first polysiloxane having one or more vinyl groups at both ends; preparing a mixture B by mixing a second siloxane-based resin with hollow glass beads, the second siloxane-based resin including a second polysiloxane having one or more vinyl groups at both ends and a third polysiloxane having Si — H bonds; obtaining a thermally conductive polymer composition by mixing the mixture a, the mixture B, and an inorganic filler; and forming the polymer composition into a predetermined form and then curing.

a method of manufacturing a thermal pad according to an exemplary embodiment of the present invention will be described in detail step by step. Here, a repeated description of the component ratios of the thermally conductive polymer composition and the features of the respective components, which have been described above, will be omitted.

The manufacturing method of the heat dissipation pad comprises the following steps:

a) Preparing mixture A by mixing a first siloxane-based resin with carbon fibers, the first siloxane-based resin including a first polysiloxane having one or more vinyl groups at both ends;

b) Mixture B is prepared by mixing a second siloxane-based resin with hollow glass beads, the second siloxane-based resin comprising a second polysiloxane having one or more vinyl groups at both ends and a third polysiloxane having Si-H bonds

c) Obtaining a thermally conductive polymer composition by mixing the mixture a, the mixture B, and a thermally conductive inorganic filler; and

d) The thermally conductive polymer composition is formed into a predetermined form and then cured, for example by thermal curing.

Before starting the above steps, the carbon fibers, the thermally conductive inorganic filler and the hollow glass beads may be dehydrated or dried to remove water components that hinder the silicone-based resin from rubberizing. Therefore, the dehydration or drying may be preferably performed at a temperature of about 130 ℃ for about 24 hours.

The preparation of the dehydrated/dried thermally conductive polymer composition may be performed at room temperature. Here, the room temperature range may be about 20 ℃ to 30 ℃, depending on the conditions in the laboratory.

Preferably, in step a), the first polysiloxane having one or more vinyl groups at both ends may be added to the carbon fiber and uniformly stirred, thereby preparing the mixture a. The first polysiloxane may be further added with a platinum catalyst and mixed. The time required to prepare mixture a may suitably be from about 1 to 2 hours.

In step B), the hollow glass beads may be suitably dispersed in a second polysiloxane having one or more vinyl groups at both ends and a third polysiloxane having Si — H bonds, thereby preparing mixture B. Thus, the second polysiloxane and the third polysiloxane may be further added with a retarder and mixed. The time required for preparing the mixed solution B may be suitably about 1 to 2 hours.

In step c), the mixed solution a and the mixed solution B, in which the carbon fibers and the hollow glass beads are uniformly distributed, respectively, are placed in a vacuum mixer together with the heat conductive inorganic filler and stirred in vacuum for about 1 to 2 hours, thereby obtaining a heat conductive polymer composition.

In step d), the thermally conductive polymer composition thus obtained may be applied on a release film, and then thermally cured at a temperature of room temperature (e.g., 25 ± 5 ℃) to 200 ℃ according to processing conditions, thereby manufacturing a product. The product thus manufactured may be in the form of a sheet or a roll.