Stretchable heat dissipation composite with anisotropic thermal conductivity and manufacturing method thereof

Abstract

A stretchable heat dissipation composite with high horizontal thermal conductivity and a method for manufacturing the same are proposed, which exhibits anisotropic thermal conductivity and can be used in flexible displays or stretchable displays. The stretchable heat dissipation composite with high horizontal thermal conductivity includes a heat dissipation pad comprising a two-dimensional heat dissipation material and a flexible support layer surrounding the heat dissipation pad, and when stretched in the longitudinal direction, it can be stretched by stretching the flexible support layer.

Description

Technology Field

[0001] The present invention relates to a stretchable heat dissipation composite having high horizontal thermal conductivity and a method for manufacturing the same, and more specifically, to a stretchable heat dissipation composite having high horizontal thermal conductivity that exhibits anisotropic thermal conductivity and can be used in a flexible display or a stretchable display, and a method for manufacturing the same. Background Technology

[0003] As electronic products become increasingly miniaturized, the chips used become highly integrated, and as battery output increases, the problem of excessive heat generation during operation has been raised. In particular, heat in small electronic products, such as mobile displays, accumulates internally, causing malfunctions and fires, which lowers the durability and reliability of the electronic products; therefore, this is pointed out as a problem that must be solved.

[0004] To prevent device degradation caused by a heat source, heat is dissipated using a heat transfer material with high thermal conductivity within the device, and most heat transfer materials use a composite with a high filling of heat dissipation filler. However, since such a composite has high strength and low elongation, there are limitations to its application when the mobile display is a flexible or stretchable display.

[0005] Furthermore, conventional thermal composites use spherical or angular thermal particles, so their horizontal and vertical thermal conductivity are similar. Therefore, they are not suitable as thermal solutions for mobile displays that require anisotropic thermal conductivity (horizontal thermal conductivity >> vertical thermal conductivity). The problem to be solved

[0012] The present invention aims to solve the above-mentioned problems, and the objective of the present invention is to provide a stretchable heat dissipation composite having high horizontal thermal conductivity that exhibits anisotropic thermal conductivity and can be used in flexible displays or stretchable displays, and a method for manufacturing the same. means of solving the problem

[0014] A stretchable heat dissipation composite having high horizontal thermal conductivity according to one embodiment of the present invention for achieving the above objective comprises a heat dissipation pad including a two-dimensional heat dissipation material and a flexible support layer surrounding the heat dissipation pad, and when stretched in the longitudinal direction, it can be stretched by stretching the flexible support layer.

[0015] The two-dimensional heat dissipation material may be at least one of graphene, carbon nanotubes, graphite, h-boron nitride, and MXene.

[0016] The heat dissipation pad may contain a two-dimensional heat dissipation material in an amount of 1 vol% to 90 vol% based on the total volume of the heat dissipation pad.

[0017] The heat dissipation pad may have a tensile modulus of 1 MPa to 1000 MPa.

[0018] The tensile modulus of the flexible support layer may be 0.1 MPa to 100 MPa, and the elongation may be 100% to 1,000%.

[0019] The flexible support layer may include at least one resin among silicone resin, acrylic resin, urethane resin, and epoxy resin.

[0020] The stretchable heat dissipation composite with high horizontal thermal conductivity according to the present invention may have a thickness of 10 μm to 10 mm.

[0021] The stretchable heat dissipation composite with high horizontal thermal conductivity according to the present invention comprises two or more heat dissipation pads, and the heat dissipation pads may be connected by a heat conduction path that can be stretched when the flexible support layer is stretched.

[0022] The shape of the heat dissipation pad can be circular or polygonal.

[0023] According to another aspect of the present invention, a method for manufacturing a stretchable heat dissipation composite having high horizontal thermal conductivity that can be stretched by stretching the flexible support layer when stretched in the longitudinal direction is provided, comprising: a step of forming a heat dissipation pad pattern including a two-dimensional heat dissipation material; and a step of forming a flexible support layer surrounding the heat dissipation pad by applying a flexible support material outside the heat dissipation pad pattern.

[0024] According to another aspect of the present invention, an electronic device is provided comprising a heat dissipation pad comprising a two-dimensional heat dissipation material and a flexible support layer surrounding the heat dissipation pad, and a stretchable heat dissipation composite having high horizontal thermal conductivity that can be stretched by stretching the flexible support layer when stretched in the longitudinal direction.

[0025] According to another aspect of the present invention, a method for manufacturing a stretchable heat dissipation composite having high horizontal thermal conductivity is provided, comprising: a step of forming a heat dissipation pad pattern including a two-dimensional heat dissipation material on a first release layer; a step of forming a first flexible support layer surrounding the heat dissipation pad by applying a flexible support material on the heat dissipation pad pattern; a step of forming a second release layer on the first flexible support layer; a step of removing the first release layer from the heat dissipation pad pattern; a step of forming a second flexible support layer surrounding the heat dissipation pad by applying a flexible support material on the heat dissipation pad pattern exposed after the first release layer is removed; and a step of removing the second release layer from the first flexible support layer. Effects of the invention

[0027] According to embodiments of the present invention, a two-dimensional heat dissipation material having anisotropic thermal conductivity can be patterned and impregnated into a stretchable polymer to obtain a stretchable heat dissipation composite, which can be used effectively in flexible displays or stretchable displays because it is possible to obtain a high elongation rate while maintaining the desired anisotropic thermal conductivity.

[0028] In addition, since the stretchable heat dissipation composite according to the present invention is impregnated with a two-dimensional heat dissipation material having anisotropic thermal conductivity, heat generated from a light source or chip spreads to a wide area rather than a local area, thereby effectively solving the problem of display failure and shortened lifespan caused by hot spots.

[0029] In addition, the stretchable heat dissipation composite according to the present invention has a two-dimensional heat dissipation material having anisotropic thermal conductivity concentrated in a rigid region, and since stretching occurs only in the flexible region, which is a flexible support layer, without change in the rigid region during stretching, the heat dissipation pad containing the two-dimensional heat dissipation material in the rigid region can maintain its initial heat dissipation characteristics without significant impact even after repeated stretching tests, thereby having the effect of obtaining a high-quality and highly reliable heat dissipation composite. Brief explanation of the drawing

[0031] FIGS. 1 to 3 are drawings provided to describe a method for manufacturing a stretchable heat dissipation composite with high horizontal thermal conductivity according to an embodiment of the present invention. FIG. 4 is a plan view of a stretchable heat dissipation composite with high horizontal thermal conductivity according to another embodiment of the present invention, FIG. 5 is a plan view of the stretchable heat dissipation composite stretched left and right, and FIG. 6 is a plan view of the stretchable heat dissipation composite stretched up and down. FIGS. 7 to 12 are drawings provided to describe a method for manufacturing a stretchable heat dissipation composite with high horizontal thermal conductivity according to another embodiment of the present invention. Specific details for implementing the invention

[0032] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, embodiments of the present invention may be modified in various different forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Although there may be components in the attached drawings that are depicted to have a specific pattern or have a predetermined thickness, this is for convenience of explanation or distinction, and therefore, even if a specific pattern and a predetermined thickness are depicted, the present invention is not limited only to the features of the depicted components.

[0033] FIGS. 1 to 3 are drawings provided to describe a method for manufacturing a stretchable heat dissipation composite having high horizontal thermal conductivity according to an embodiment of the present invention. According to the present embodiment, a method for manufacturing a stretchable heat dissipation composite having high horizontal thermal conductivity (hereinafter referred to as a stretchable heat dissipation composite) that is stretchable by stretching the flexible support layer when stretched in the longitudinal direction is provided, comprising: a step of forming a heat dissipation pad pattern including a two-dimensional heat dissipation material; and a step of forming a flexible support layer surrounding the heat dissipation pad by applying a flexible support material to the outside of the heat dissipation pad pattern.

[0034] First, heat dissipation pads (120) spaced apart from each other are formed on a different layer (110) (Fig. 1). The heat dissipation pads (120) include a two-dimensional heat dissipation material. Examples of two-dimensional heat dissipation materials include at least one of graphene, carbon nanotubes, graphite, h-boron nitride, and MXene.

[0035] These two-dimensional heat dissipation materials are materials in which horizontal thermal conductivity is much greater than vertical thermal conductivity due to the characteristics of their two-dimensional shape, and are useful in cases where heat released by a heat dissipation means must not move to the display component located in the vertical direction, such as in mobile displays. However, two-dimensional heat dissipation materials have a disadvantage for use in stretchable or flexible displays because they exhibit low flexibility or elongation due to the characteristics of their shape.

[0036] When forming a heat dissipation pad (120) containing such a two-dimensional heat dissipation material on a release layer (110), the heat dissipation pads (120) can be spaced apart from each other, and a flexible support layer (130) containing a flexible material can be formed between the spaced-apart heat dissipation pads (120) (Fig. 2).

[0037] A heat dissipation pad pattern can be formed by coating an ink or paste containing a two-dimensional heat dissipation material onto a release layer (110) through a metal mask roll. The heat dissipation pad (120) may contain a two-dimensional heat dissipation material in an amount of 1 vol% to 90 vol% based on the total volume of the heat dissipation pad. If the content of the two-dimensional heat dissipation material in the heat dissipation pad (120) is 1 vol% or less, the thermal conductivity is very low and the desired heat dissipation characteristics cannot be obtained, and if it is 90 vol% or more, the flexibility is low and the heat dissipation composite may not be stretched even with the presence of a flexible support layer (130). The shape of the heat dissipation pad (120) may be circular or polygonal.

[0038] A flexible support material is applied over the heat dissipation pad pattern on the release layer (110) to form a flexible support layer surrounding the heat dissipation pad. The flexible support material is, for example, a polymer resin, and a material having the characteristic of being able to impart flexibility to the entire heat dissipation composite by considering the characteristics and content of the two-dimensional heat dissipation material of the heat dissipation pad (120) can be used.

[0039] For example, the heat dissipation pad (120) may have a tensile modulus of 1 MPa to 1000 MPa, the tensile modulus of the flexible support layer (130) may be 0.1 MPa to 100 MPa, and the elongation may be 100% to 1,000%. Any polymer resin that satisfies these characteristics may be used, for example, at least one resin among silicone resin, acrylic resin, urethane resin, and epoxy resin that satisfies the tensile modulus or elongation characteristics may be used.

[0040] Afterward, a stretchable heat dissipation composite (100) can be obtained by removing the release layer (110). The stretchable heat dissipation composite (100) with high horizontal thermal conductivity manufactured according to the present embodiment includes a heat dissipation pad (120) containing a two-dimensional heat dissipation material and a flexible support layer (130) surrounding the heat dissipation pad (120), and when stretched in the longitudinal direction, it can be stretched by stretching the flexible support layer (Fig. 3). In addition, the stretchable heat dissipation composite (100) exhibits a characteristic in which horizontal thermal conductivity is higher than vertical thermal conductivity. The stretchable heat dissipation composite with high horizontal thermal conductivity according to the present invention may have a thickness of 10 μm to 10 mm.

[0041] FIG. 4 is a plan view of a stretchable heat dissipation composite with high horizontal thermal conductivity according to another embodiment of the present invention, FIG. 5 is a plan view of the stretchable heat dissipation composite stretched left and right, and FIG. 6 is a plan view of the stretchable heat dissipation composite stretched up and down.

[0042] The stretchable heat dissipation composite (100) according to the present embodiment has a structure in which a flexible support layer (130) surrounds each heat dissipation pad (120). Hereinafter, since the flexible support layer (130) has a high elongation rate and is flexible, the portion of the flexible support layer (130) is referred to as a soft region with a small modulus, and the heat dissipation pad (120) is referred to as a rigid region that includes a two-dimensional heat dissipation material, has a large modulus, is difficult to stretch, and is not flexible.

[0043] Referring to FIG. 4, the heat dissipation pads (120) are spaced apart from each other, and are spaced apart by a left-right spacing distance (d1) in the left-right direction and a top-bottom spacing distance (d2) in the top-bottom direction relative to the drawing. When such a stretchable heat dissipation composite (100) is stretched, the rigid region with a large modulus undergoes little change, and the flexible region with a small modulus is mainly stretched.

[0044] FIG. 5 is a plan view of a stretchable heat dissipation composite in a left-right stretched state. When stretched left-right, the left-right spacing distance (d1) between the heat dissipation pads (120) is deformed as the flexible support layer (130) between the heat dissipation pads (120) is stretched. 11 It increases by ). At this time, the heat dissipation pad (120) is not stretched or is stretched to an insignificant value. When stretching left and right, the flexible support layer (130) between the heat dissipation pads (120) arranged vertically is not stretched, so the vertical spacing distance (d2) is deformed vertical spacing distance (d 21 It is the same as ).

[0045] On the other hand, as shown in FIG. 6, when the stretchable heat dissipation composite (100) is stretched in the vertical direction, the rigid region undergoes almost no change, and only the flexible region is stretched in the vertical direction. Therefore, the vertical spacing (d2) between the heat dissipation pads (120) is deformed as the flexible support layer (130) between the heat dissipation pads (120) is stretched, resulting in a deformed vertical spacing (d 22 It increases by ). At this time, the heat dissipation pad (120) is not stretched or is stretched to an insignificant value. When stretching vertically, the flexible support layer (130) between the heat dissipation pads (120) arranged horizontally is not stretched, so the horizontal spacing distance (d1) is a deformed horizontal spacing distance (d 12 It is the same as ).

[0046] At this time, it is desirable to form a thermal conduction path (not shown) capable of connecting a thermally conductive rigid region to the stretched flexible region. For example, if adjacent heat dissipation pads are connected by a wire shaped like a spring, the wire can be stretched together with the stretching of the flexible region while forming a thermal conduction path between the heat dissipation pads of the rigid region, thereby maintaining thermal conductivity at all times. After stretching, the wire can return to its original shape, similar to a flexible support layer.

[0047] FIGS. 7 to 12 are drawings provided to describe a method for manufacturing a stretchable heat dissipation composite with high horizontal thermal conductivity according to another embodiment of the present invention.

[0048] In this embodiment, first, a heat dissipation pad (120) pattern including a two-dimensional heat dissipation material is formed on a first release layer (111) (Fig. 7), and a first flexible support layer (131) surrounding the heat dissipation pad is formed by applying a flexible support material on the heat dissipation pad (120) pattern (Fig. 8).

[0049] Afterwards, a second release layer (112) is formed on the first flexible support layer (131) (Fig. 9). Once the second release layer (112) is formed, the first release layer (111) is removed from the heat dissipation pad (120) pattern on the opposite side (Fig. 10). When the first release layer (111) is removed, the heat dissipation pad (120) is exposed, and a flexible support material is applied again on the exposed heat dissipation pad (120) pattern to form a second flexible support layer (132) that surrounds the heat dissipation pad (120) (Fig. 11).

[0050] Finally, when the second release layer (112) is removed from the upper first flexible support layer (131), a stretchable heat dissipation composite (100) with high horizontal thermal conductivity is manufactured, in which the entire pattern of the heat dissipation pad (120) is surrounded by the first flexible support layer (131) and the second flexible support layer (132) (Fig. 12).

[0051] In the present embodiment, the stretchable heat dissipation composite (100) has a flexible support material surrounding the entire heat dissipation pad pattern. The heat dissipation pad (120), which includes a two-dimensional heat dissipation material with excellent horizontal thermal conductivity, conducts heat mostly in the horizontal direction but also conducts heat in the vertical direction. If the stretchable heat dissipation composite (100) is used in a device such as a stretchable or flexible display, a display is present on the upper surface of the stretchable heat dissipation composite (100). That is, the stretchable heat dissipation composite (100) must dissipate the heat generated by the display on the upper surface in the horizontal direction; if the received heat is transferred back in the vertical direction, it may have an adverse effect on the operation of the display.

[0052] In the present embodiment, the stretchable heat dissipation composite (100) has a flexible support layer located on the upper and lower portions of the heat dissipation pad (120) to provide flexibility to the stretchable heat dissipation composite (100) and at the same time prevent heat received from a heating element located on the upper and lower portions of the stretchable heat dissipation composite (100) from being returned to the heating element, thereby enabling efficient heat dissipation performance.

[0053] According to another aspect of the present invention, an electronic device (not shown) is provided that includes a heat dissipation pad comprising a two-dimensional heat dissipation material and a flexible support layer surrounding the heat dissipation pad, and a stretchable heat dissipation composite having high horizontal thermal conductivity that can be stretched by stretching the flexible support layer when stretched in the longitudinal direction.

[0054] Although embodiments of the present invention have been described above, those skilled in the art may modify and change the present invention in various ways by adding, changing, deleting, or adding components, etc., without departing from the spirit of the invention as described in the claims, and such modifications and changes are also to be included within the scope of the rights of the present invention. Explanation of the symbols

[0056] 100: Stretchable heat dissipation composite 110, 111, 112: Heterogeneous layer 120: Thermal pad 130, 131, 132: Flexible support layer d1, d 11 , d 12 : Left and right spacing between heat dissipation pads d2, d 21 , d 22 : Upper and lower spacing between thermal pads

Claims

Claim 1 A stretchable heat dissipation composite having high horizontal thermal conductivity, comprising a heat dissipation pad including a two-dimensional heat dissipation material and a flexible support layer surrounding the heat dissipation pad, wherein when stretched in the longitudinal direction, the flexible support layer is stretchable, and the elongation rate of the flexible support layer is 100% to 1,000%. Claim 2 A stretchable heat dissipation composite having high horizontal thermal conductivity according to claim 1, wherein the two-dimensional heat dissipation material is at least one of graphene, carbon nanotubes, graphite, h-boron nitride, and MXene. Claim 3 A stretchable heat dissipation composite having high horizontal thermal conductivity according to claim 1, characterized in that the heat dissipation pad comprises a two-dimensional heat dissipation material in an amount of 1 vol% to 90 vol% based on the total volume of the heat dissipation pad. Claim 4 The stretchable heat dissipation composite having high horizontal thermal conductivity according to claim 1, wherein the heat dissipation pad has a tensile modulus of 1 MPa to 1000 MPa. Claim 5 A stretchable heat dissipation composite having high horizontal thermal conductivity, characterized in that, in claim 1, the tensile modulus of the flexible support layer is 0.1 MPa to 100 MPa and the elongation is 100% to 1,000%. Claim 6 A stretchable heat dissipation composite having high horizontal thermal conductivity according to claim 5, wherein the flexible support layer comprises at least one resin selected from silicone resin, acrylic resin, urethane resin, and epoxy resin. Claim 7 A stretchable heat dissipation composite having high horizontal thermal conductivity according to claim 1, characterized by having a thickness of 10 μm to 10 mm. Claim 8 A stretchable heat dissipation composite having high horizontal thermal conductivity according to claim 1, comprising two or more heat dissipation pads, wherein the heat dissipation pads are connected by a heat conduction path that can be stretched when the flexible support layer is stretched. Claim 9 A stretchable heat dissipation composite having high horizontal thermal conductivity, characterized in that, in claim 1, the shape of the heat dissipation pad is circular or polygonal. Claim 10 A method for manufacturing a stretchable heat dissipation composite having high horizontal thermal conductivity that is stretchable by stretching of the flexible support layer when stretched in the longitudinal direction, comprising: a step of forming a heat dissipation pad pattern including a two-dimensional heat dissipation material; and a step of forming a flexible support layer surrounding the heat dissipation pad by applying a flexible support material outside the heat dissipation pad pattern; wherein the elongation rate of the flexible support layer is 100% to 1,000%. Claim 11 An electronic device comprising a stretchable heat dissipation composite having high horizontal thermal conductivity according to claim 1. Claim 12 A method for manufacturing a stretchable heat dissipation composite having high horizontal thermal conductivity, comprising: a step of forming a heat dissipation pad pattern including a two-dimensional heat dissipation material on a first release layer; a step of forming a first flexible support layer surrounding the heat dissipation pad by applying a flexible support material on the heat dissipation pad pattern; a step of forming a second release layer on the first flexible support layer; a step of removing the first release layer from the heat dissipation pad pattern; a step of forming a second flexible support layer surrounding the heat dissipation pad by applying a flexible support material on the heat dissipation pad pattern exposed after the first release layer is removed; and a step of removing the second release layer from the first flexible support layer; wherein the elongation rate of the first flexible support layer and the second flexible support layer is 100% to 1,000%.

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