KR20220030104A - Composite material - Google Patents

Abstract

The present invention provides a composite material and a method for making the same. In the present invention, a composite material that has excellent thermal conductivity, excellent mechanical properties such as impact resistance, and can provide effective realize thermal contact even in a very narrow space can be provided. The composite material can achieve intimate thermal contact even with highly stepped surfaces. The composite material comprises: a metal foam; a polymer component; and a substance present in the polymer component.

Description

COMPOSITE MATERIAL

This application relates to a composite material.

Heat dissipation materials can be used in a variety of applications. For example, since a battery or various electronic devices generate heat during operation, a material capable of effectively controlling such heat is required.

As a material with good heat dissipation properties, ceramic materials with good thermal conductivity are known, but since these materials have poor workability, a composite material prepared by mixing the ceramic filler and the like having high thermal conductivity in a polymer matrix may be used.

However, by the above method, a problem occurs because a large amount of filler component must be applied to ensure high thermal conductivity. For example, in the case of a material containing a large amount of filler component, the material itself tends to become hard, and in this case, impact resistance and the like are inferior.

The heat dissipation material is usually disposed between the heat source and the heat sink. However, when a step is formed on the surface of the heat source or heat sink in contact with the heat dissipation material, close thermal contact between the heat dissipation material and the heat source or heat sink is not achieved, and in this case, the overall thermal resistance is increased. .

This application relates to a composite material. In the present application, a composite material that has excellent thermal conductivity, has excellent mechanical properties such as impact resistance, and can effectively realize thermal contact even in a very narrow space can be provided, and the composite material has close thermal contact even with a heavily stepped surface can be achieved

Among the physical properties mentioned in this specification, when the measured temperature affects the corresponding physical property, unless otherwise specified, the physical property is measured at room temperature. The term room temperature is a natural temperature that is not heated or reduced, for example, any temperature within the range of about 10 °C to 30 °C, may mean a temperature of about 23 °C or about 25 °C.

This application relates to a composite material. In the present application, the term composite material includes at least a metal foam and a polymer component, and may mean a material in which the polymer component is present in pores formed in the metal foam and/or on the surface of the metal foam.

As used herein, the term metal foam or metal skeleton refers to a porous structure including a metal as a main component. In the above, having a metal as a main component means that the ratio of the metal is 55 wt% or more, 60 wt% or more, 65 wt% or more, 70 wt% or more, 75 wt% or more, 80 wt% based on the total weight of the metal foam or metal skeleton It means a case of weight % or more, 85 weight % or more, 90 weight % or more, or 95 weight % or more. The upper limit of the ratio of the metal included as the main component is not particularly limited, and may be, for example, about 100% by weight, 99% by weight, or 98% by weight.

As used herein, the term porosity may mean a case in which porosity is at least 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, or 40% or more. The upper limit of the porosity is not particularly limited, but may be, for example, about 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, or 50% or less. . A method of obtaining the porosity is not particularly limited. For example, in the case of a metal foam, a known method of checking the porosity through the density of the metal foam may be applied.

The composite material has high thermal conductivity, and thus may be used as a material for controlling heat, such as, for example, a heat dissipation material. In addition, the composite material has excellent flexibility and impact resistance, and can achieve excellent thermal contact even in a very narrow space. In particular, even when a step is severely formed on the surface to which the composite material is applied, the composite material may achieve a close thermal contact with the surface to realize low thermal resistance.

For example, the composite material has a thermal conductivity of about 0.4 W/mK or more, 0.45 W/mK or more, 0.5 W/mK or more, 0.55 W/mK or more, 0.6 W/mK or more, 0.65 W/mK or more, 0.7 W/mK or more. mK or more, 0.75 W/mK or more, 0.8 W/mK or more, 0.85 W/mK or more, 0.9 W/mK or more, 0.95 W/mK or more, 1 W/mK or more, 1.5 W/mK or more, 2, W/mK It may be 2.5 W/mK or more, 3 W/mK or more, 3.5 W/mK or more, 4 W/mK or more, 4.5 W/mK or more, or 5 W/mK or more. The higher the thermal conductivity of the composite material, the higher the composite material can have an excellent thermal control function, so it is not particularly limited, and in one example, about 100 W/mK or less, 90 W/mK or less, 80 W/mK or less, 70 W/mK or less or less, 60 W/mK or less, 50 W/mK or less, 40 W/mK or less, 30 W/mK or less, 20 W/mK or less, or 15 W/mK or less. A method of measuring the thermal conductivity is not particularly limited.

For example, the thermal conductivity can be obtained by the formula of thermal conductivity = AХBХC by obtaining the thermal diffusivity (A), specific heat (B) and density (C) of the composite, in which the thermal diffusivity (A) is a laser flash Method (LFA equipment, model name: LFA467) can be used to measure, specific heat can be measured using DSC (Differential Scanning Calorimeter) equipment, and density can be measured using Archimedes method. In one example, the thermal conductivity may be a value with respect to the thickness direction (Z-axis) of the composite material.

Such excellent thermal conductivity properties of the composite material can be achieved by selecting the metal foam and appropriately compounding the polymer component. That is, since the thickness of the metal foam to be described later has pore characteristics, the metal foam can effectively form a heat transfer path in the composite material. In addition, since the metal foam is complexed with a polymer component having an appropriate characteristic and an appropriate content, the polymer component can properly fill the pores of the metal foam and further improve thermal conductivity. In addition, the composite polymer component can improve the flexibility and mechanical properties of the composite material. In addition, the functions of other components (for example, a material having a melting point in the following predetermined range or a thermally conductive filler) included in the polymer component by the complexation as described above are the heat transfer path of the metal foam, flexibility, mechanical properties such as impact resistance. It can be maintained without damaging the physical properties.

In order to efficiently achieve the above-mentioned complexation of the metal foam and the polymer component, the properties of the metal foam can be controlled. For example, when the type of the polymer component to be complexed is the same, the amount of the polymer component to be complexed increases in proportion to the pore size, porosity, and thickness of the metal foam. Accordingly, suitable complexing can be achieved by adjusting the pore size, porosity and/or thickness.

In one example, the metal foam may have a porosity of about 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, or 50% or less. The porosity may be 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, or 40% or more in another example. As for the porosity, a known method of confirming the porosity through the density of the metal foam may be applied. It is possible to achieve suitable complexation with the polymer component within the above range, and effectively form a heat transfer path within the composite material.

The size of the pores of the metal foam may be in the range of approximately 1 μm to 50 μm. The pore size can be confirmed by photographing the metal foam at a magnification of 500 times using an electronic optical microscope (SEM, JEOL, JSM-7610F). In addition, when the pore size is checked, if the pore is not circular, the major axis and the minor axis are measured respectively and then averaged to obtain the pore size. In addition, the size of the pores may be the size of the largest pore among the plurality of pores formed in the metal foam, the size of the smallest pore size, or an average value of the sizes of the pores. In another example, the size of the pores is 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, 4.5 μm or more, 5 μm or more, 5.5 μm or more, 6 μm or more, 6.5 μm or more, 7 μm or more, 7.5 μm or more, 8 μm or more, 8.5 μm or more, 9 μm or more, 9.5 μm or more, 10 μm or more, 10.5 μm or more, 11 μm or more, 11.5 μm or more, 12 μm or more, 12.5 μm or more, 13 μm or more, 13.5 μm or more, 14 μm or more, 14.5 or more, 15 μm or more, 15.5 μm or more, 16 μm or more, 16.5 μm or more, 17 μm or more, 17.5 μm or more, 18 μm or more, 18.5 μm or more, 19 μm or more, 19.5 μm or more, or 20, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 18 μm or less, 16 μm or less, 14 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, 6 μm or less, or 4 μm or less. Suitable complexation with the polymer component can be achieved within the above range.

As described above, the metal foam may be in the form of a film. The thickness of the film may be, for example, about 1,000 μm or less, about 900 μm or less, about 800 μm or less, about 700 μm or less, about 600 μm or less, about 500 μm or less, about 400 μm or less, about 300 μm or less, It may be on the order of about 200 μm or less or about 150 μm or less. It is possible to achieve suitable complexation with the polymer component within the above range, and effectively form a heat transfer path within the composite material. The lower limit of the thickness of the metal foam is not particularly limited, and for example, about 10 μm or more, about 20 μm or more, about 30 μm or more, about 40 μm or more, about 45 μm or more, about 50 μm or more, about 55 μm or more, about 60 μm at least about 65 μm, at least about 70 μm, at least about 75 μm, at least about 80 μm, at least about 85 μm, at least about 90 μm, or at least about 95 μm.

In the present specification, when the thickness of the object is not constant, the thickness may be the minimum thickness, the maximum thickness, or the average thickness of the object.

The metal foam may be made of a metal having high thermal conductivity. In one example, the metal foam has a thermal conductivity of about 8 W/mK or more, about 10 W/mK or more, about 15 W/mK or more, about 20 W/mK or more, about 25 W/mK or more, about 30 W/ mK or more, about 35 W/mK or more, about 40 W/mK or more, about 45 W/mK or more, about 50 W/mK or more, about 55 W/mK or more, about 60 W/mK or more, about 65 W/mK or more or more, about 70 W/mK or more, about 75 W/mK or more, about 80 W/mK or more, about 85 W/mK or more, or about 90 W/mK or more, a metal or metal alloy. The thermal conductivity is not particularly limited because it is possible to secure the desired thermal control characteristics while applying a small amount of metal foam as the numerical value is higher, for example, it may be about 1,000 W/mK or less.

The skeleton of the metal foam may be made of various types of metals or metal alloys. Among these metals or metal alloys, a material capable of exhibiting thermal conductivity in the above-mentioned range may be selected. As such a material, any one metal selected from the group consisting of copper, gold, silver, aluminum, nickel, iron, cobalt, magnesium, molybdenum, tungsten and zinc or an alloy of two or more of the above may be exemplified. It is not limited.

These metal foams are known in various ways, and a method of manufacturing the metal foam is also known in various ways. In the present application, such a known metal foam or a metal foam manufactured by the above known method may be applied.

As a method of manufacturing a metal foam, a method of sintering a composite material of a metal and a pore former such as a salt, a method of coating a metal on a support such as a polymer foam, and sintering in that state, a slurry method, etc. are known. In addition, the metal foam is disclosed in Korean Application Nos. 2017-0086014, 2017-0040971, 2017-0040972, 2016-0162154, 2016-0162153 or 2016-0162152, which are prior applications of the present applicant. It can also be manufactured according to the method.

The polymer component to be complexed with the metal foam as described above may be present on the surface and/or inside (pores of the metal foam) of the metal foam in the form of a film.

The polymer component forms a surface layer on at least one surface of the metal foam, or may be filled in pores inside the metal foam, and in some cases, while forming the surface layer, it is also filled in the pores inside the metal foam there may be In the case of forming the surface layer, the polymer component may form a surface layer on at least one surface, a part of, or all surfaces of the surface of the metal foam. In one example, the polymer component may form a surface layer on at least the upper and/or lower surface of the main surface of the metal foam. The surface layer may be formed to cover the entire surface of the metal foam, or may be formed to cover only a portion of the surface.

The composite material further comprises a polymer component present on the surface of the metal foam or inside the metal foam as described above, in this case the ratio (T) of the thickness (MT) of the metal foam and the thickness (T) of the composite material /MT) may be 2.5 or less. In another example, the ratio of the thickness may be about 2 or less, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.15 or less, or 1.1 or less. The lower limit of the ratio of the thickness is not particularly limited, but in one example may be greater than about 1, greater than about 1.01, greater than about 1.02, greater than about 1.03, greater than about 1.04, or greater than about 1.05. While the desired thermal conductivity is secured under this thickness ratio, a composite material having excellent workability, impact resistance, and the like can be provided. In particular, under the above ratio, the function of another material such as a material of a predetermined melting point and/or a thermally conductive filler present in the polymer component can be exhibited without damaging the heat transfer path formed by the metal foam and the flexibility and mechanical properties of the composite material.

The type of polymer component included in the composite material of the present application is not particularly limited, and may be selected in consideration of, for example, processability, impact resistance, and insulation properties of the composite material. Examples of the polymer component that can be applied in the present application include, but are not limited to, one or more selected from the group consisting of a well-known acrylic resin, silicone resin, epoxy resin, urethane resin, amino resin, and phenol resin.

The ductility of the polymer component can be controlled in order to effectively achieve thermal contact even with the surface of the high level difference between the polymer component and the surface by applying a material having a predetermined melting point, which will be described later. For example, the polymer component may have a glass transition temperature (Tg) within the range of -300°C to 0°C or a melting temperature (Tm) within the range of -100°C to 0°C. The polymer component may have either one of the glass transition temperature and the melting temperature, or both. When a material having a predetermined melting point to be described later is applied to the polymer component having such a glass transition temperature and/or melting temperature, close thermal contact with the surface can be achieved even when the composite material is applied to a surface with a high level of step, and such The properties may be maintained even when a material of a different type from the material having a predetermined melting point, such as a thermally conductive filler, which will be described later, is included in the polymer component.

The glass transition temperature is -280 ℃ or more, -260 ℃ or more, -240 ℃ or more, -220 ℃ or more, -200 ℃ or more, -180 ℃ or more, -160 ℃ or more, -140 ℃ or more, or -120 in another example. ℃ or higher, -20 °C or lower, -40 °C or lower, -60 °C or lower, -80 °C or lower, -100 °C or lower, or -120 °C or lower.

In addition, the melting temperature is -90 ℃ or more, -80 ℃ or more, -70 ℃ or more, -60 ℃ or more, or -50 ℃ or more in another example, or -10 ℃ or less, -20 ℃ or less, -30 ℃ or less, It may be about -40°C or less or -50°C or less.

When the polymer component has both a glass transition temperature and a melting temperature, the difference between the glass transition temperature and the melting temperature may be in the range of about 0°C to 200°C. The difference is a value obtained by subtracting the smaller value from the larger value of the glass transition temperature and the melting temperature. In one example, the melting temperature has a larger value than the glass transition temperature. The difference is, in another example, 10 °C or higher, 20 °C or higher, 30 °C or higher, 40 °C or higher, 50 °C or higher, 60 °C or higher, 70 °C or higher, 80 °C or higher, or 90 °C or higher, 190 °C or lower, 180 °C or higher or less, 170 °C or less, 160 °C or less, 150 °C or less, 140 °C or less, 130 °C or less, 120 °C or less, 110 °C or less, 100 °C or less, 90 °C or less, 80 °C or less, or 70 °C or less.

The glass transition temperature and the melting temperature can be measured by applying a general method of measuring the corresponding temperature for the polymer component.

The polymer component may be formed by using a component having the glass transition temperature and/or melting temperature among the various polymer materials described above.

In one example, the ratio (MV/PV) of the volume (PV) of the polymer component included in the composite to the volume (MV) of the metal foam may be 10 or less. In another example, the ratio (MV/PV) may be about 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, 2 or less, 1 or less, or 0.5 or less. In another example, the volume ratio (MV/PV) is 0.01 or more, 0.1 or more, 0.15 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, 0.4 or more, 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more, 0.65 or more. It may be about 0.7 or more, 0.75 or more, or 0.8 or more. The volume ratio can be calculated through the weight of the polymer component and the metal foam included in the composite and the density of the components.

In the composite material, the polymer component may include a material having a melting point in the range of 35°C to 100°C. In another example, the melting point of the material is 40°C or more, 45°C or more, or 50°C or more, or 95°C or less, 90°C or less, 85°C or less, 80°C or less, 75°C or less, 70°C or less, 65°C or less, 60 It may be about ℃ or less or 55 ℃ or less. These materials can be combined with the aforementioned polymer components to achieve intimate thermal contact with the composite material, even when applied to a highly stepped surface.

The type of the material that can be applied is not particularly limited, and may be variously selected as long as it has the above melting point. For example, a hydrocarbon compound such as paraffin, a fatty acid compound, a polyol compound, a high molecular compound, or an inorganic hydrate may be applied as the material. In the above, as the hydrocarbon compound, usually a C _n H _2n+2 series compound (n is 19 or more or within the range of 20 to 30), etc. may be used, and as the high molecular compound, a PEG (poly(ethylene glycol)) compound, etc. this can be used Examples of inorganic hydrates include calcium chloride hexahydrate (CaCl ₂ .6H ₂ O), sodium sulfate decahydrate (Na ₂ SO ₄ .10H ₂ O), sodium phosphate dodecahydrate (Na ₂ HPO ₄ .12H2O), zinc nitrate hexahydrate (Zn(NO ₃ ) ₂ ·6H ₂ O), iron(iii) chloride hexahydrate (FeCl ₃ ·6H ₂ O), calcium chloride tetrahydrate (CaCl ₂ ·4H ₂ O), calcium nitrate tetrahydrate (CaCl ₂ ·4H) ₂ O), sodium sulfate pentahydrate (Na ₂ S ₂ O ₃ ·5H ₂ O) and/or sodium acetate trihydrate (C ₂ H ₃ NaO ₂ ·3H ₂ O).

However, the material applicable in the present application is not limited to the above, it is possible to mix with a polymer component, and if it has a melting point in the above-mentioned range, it can be applied without limitation.

In addition, the melting point of the material can be measured in a known manner.

The material may be included in the composite material in an amount within the range of about 5 to 40 parts by weight based on 100 parts by weight of the polymer component. The ratio is, in another example, 7 parts by weight or more, 9 parts by weight or more, 11 parts by weight or more, 13 parts by weight or more, 15 parts by weight or more, 17 parts by weight or more, 19 parts by weight or more, 21 parts by weight or more, or 23 parts by weight or more. or more, or 38 parts by weight or less, 36 parts by weight or less, 34 parts by weight or less, 32 parts by weight or less, 30 parts by weight or less, 28 parts by weight or less, 26 parts by weight or less, 24 parts by weight or less, 22 parts by weight or less, 20 parts by weight or less It may be about parts by weight or less, 18 parts by weight or less, 16 parts by weight or less, 14 parts by weight or less, or 12 parts by weight or less. Within this range, it is possible to impart softness that can achieve close thermal contact with various surfaces to the composite material without impairing or improving the advantages of the composite material.

In one example, the difference (TM-Tg) between the glass transition temperature (Tg) of the polymer component and the melting point (TM) of the material having the melting point in the range of 35°C to 100°C (TM-Tg) may be in the range of 50°C to 500°C there is. By controlling the melting point and the like within this range, the intended purpose of the composite material may be more effectively achieved, and appropriate mixing may be achieved in the mixing process to be described later. The difference is in another example 60 ℃ or more, 70 ℃ or more, 80 ℃ or more, 90 ℃ or more, 100 ℃ or more, 110 ℃ or more, 120 ℃ or more, 130 ℃ or more, 140 ℃ or more, 150 ℃ or more, 160 ℃ or more, 170 °C or higher or 180 °C or higher, 480 °C or lower, 460 °C or lower, 440 °C or lower, 420 °C or lower, 400 °C or lower, 380 °C or lower, 360 °C or lower, 340 °C or lower, 320 °C or lower, 300 °C or lower, 280 °C or lower ℃ or lower, 260 °C or lower, 240 °C or lower, 220 °C or lower, 200 °C or lower, or 180 °C or lower.

In one example, the difference (TM-Tm) between the melting temperature (Tm) of the polymer component and the melting point (TM) of the material having the melting point in the range of 35°C to 100°C (TM-Tm) may be in the range of 50°C to 500°C . By controlling the melting point and the like within this range, the intended purpose of the composite material may be more effectively achieved, and appropriate mixing may be achieved in the mixing process to be described later. The difference is in another example 60 °C or higher, 70 °C or higher, 80 °C or higher, 90 °C or higher, or 95 °C or higher, or 480 °C or lower, 460 °C or lower, 440 °C or lower, 420 °C or lower, 400 °C or lower, 380 °C or lower , 360 °C or lower, 340 °C or lower, 320 °C or lower, 300 °C or lower, 280 °C or lower, 260 °C or lower, 240 °C or lower, 220 °C or lower, 200 °C or lower, 180 °C or lower, 160 °C or lower, 140 °C or lower, 120 °C or lower It may be about °C or less or 110 °C or less.

In particular, the effect can be further maximized by controlling the ratio of the metal foam to the polymer component and the ratio of the polymer component to the material.

That is, the ratio (MV/PV) of the volume (PV) of the polymer component and the volume (MV) of the metal foam in the composite is 10 or less, and the material having the melting point in the range of 35°C to 100°C is the polymer component It may be included in the range of 5 to 40 parts by weight based on 100 parts by weight. More specifically, the volume ratio (MV/PV) and parts by weight of the material may be controlled within the above-mentioned range.

The composite material may include additional necessary components in addition to the above components.

For example, in the composite material, the polymer component forms a surface layer on at least one surface of the metal foam. In this case, a thermally conductive filler may be included in the surface layer.

The term thermally conductive filler means a filler having a thermal conductivity of at least about 1 W/mK, at least about 5 W/mK, at least about 10 W/mK, or at least about 15 W/mK. The thermal conductivity of the thermally conductive filler may be about 400 W/mK or less, about 350 W/mK or less, or about 300 W/mK or less. The type of the thermally conductive filler is not particularly limited, and, for example, a ceramic filler or a carbon-based filler may be applied. As such a filler, alumina, aluminum nitride (AlN), boron nitride (BN), silicon nitride, SiC or BeO, or a filler such as carbon nanotube or graphite may be exemplified, but is limited thereto not.

The shape or ratio of the filler included in the surface layer is not particularly limited. In one example, the shape of the filler may have various shapes, such as an approximately spherical shape, a needle shape, a plate shape, a dendrite shape, or a star shape, but is not particularly limited thereto.

In one example, the thermally conductive filler may have an average particle diameter in the range of 0.001 μm to 80 μm. In another example, the average particle diameter of the filler may be 0.01 μm or more, 0.1 or more, 0.5 μm or more, 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, 5 μm or more, or about 6 μm or more. In another example, the average particle diameter of the filler is about 75 μm or less, about 70 μm or less, about 65 μm or less, about 60 μm or less, about 55 μm or less, about 50 μm or less, about 45 μm or less, about 40 μm or less, about 35 μm or less, about 30 μm or less, about 25 μm or less, about 20 μm or less, about 15 μm or less, about 10 μm or less, or about 5 μm or less.

The average particle diameter of the filler may be a so-called D50 particle diameter. D50 particle size is the particle diameter (median diameter) at 50% cumulative by volume of the particle size distribution. am. The D50 particle size as described above may be measured by a laser diffraction method.

The thermally conductive filler of the above average particle diameter does not impair the advantages of the composite (especially, the ductility formed by the polymer component and the material having a melting point in the predetermined range), or rather improves, while improving the thermal conductivity of the composite. there is.

The proportion of the filler may be adjusted within a range in which desired properties are secured or not damaged. In one example, the filler may be included in an amount of about 80 vol% or less in a volume ratio in the composite material. In the above, the volume ratio is a numerical value calculated based on the weight and density of each of the components constituting the composite material, for example, the metal foam, the polymer component, and the filler.

The volume ratio is about 75 vol% or less, 70 vol% or less, 65 vol% or less, 60 vol% or less, 55 vol% or less, 50 vol% or less, 45 vol% or less, 40 vol% or less, 35 vol% or less in another example % or less, or about 30 vol% or less, or about 1 vol% or more, 2 vol% or more, 3 vol% or more, 4 vol% or more, or 5 vol% or more.

In another example, the thermally conductive filler may be included in the composite material in an amount of 10 to 250 parts by weight based on 100 parts by weight of the polymer component. In another example, the ratio is 13 parts by weight or more, 15 parts by weight or more, 17 parts by weight or more, 19 parts by weight or more, 21 parts by weight or more, 23 parts by weight or more, 25 parts by weight or more, 27 parts by weight or more, or 29 parts by weight or more. or 240 parts by weight or less, 230 parts by weight or less, 220 parts by weight or less, 210 parts by weight or less, 200 parts by weight or less, 190 parts by weight or less, 180 parts by weight or less, 170 parts by weight or less, 160 parts by weight or less, 150 parts by weight or less or less, 140 parts by weight or less, 130 parts by weight or less, 120 parts by weight or less, 110 parts by weight or less, 100 parts by weight or less, 90 parts by weight or less, 80 parts by weight or less, 70 parts by weight or less, 60 parts by weight or less, 50 parts by weight or less or less, 48 parts by weight or less, 46 parts by weight or less, 44 parts by weight or less, 42 parts by weight or less, 40 parts by weight or less, 38 parts by weight or less, 36 parts by weight or less, 34 parts by weight or less, 32 parts by weight or less, 30 parts by weight or less or less or about 28 parts by weight or less.

. In the above ratio, it is possible to improve the thermal conductivity of the composite material while not impairing or improving the advantages of the composite material (especially, the ductility formed by the polymer component and the material having a melting point in the predetermined range).

In particular, by simultaneously controlling the ratio of the metal foam to the polymer component, the ratio of the polymer component to the material having a melting point in the predetermined range, and the ratio of the thermally conductive filler, the effect can be further maximized.

That is, in the composite, the ratio (MV/PV) of the volume (PV) of the polymer component to the volume (MV) of the metal foam is 10 or less, and the thermally conductive filler is 15 to 50 parts by weight relative to 100 parts by weight of the polymer component Included within the range, the melting point of the material within the predetermined range may be included in the range of 5 to 40 parts by weight based on 100 parts by weight of the polymer component. The volume ratio (MV/PV), the weight part of the material having the melting point in the predetermined range, and the weight part of the thermally conductive filler may be more specifically controlled within the above-mentioned range.

The present application also relates to a method for manufacturing such a composite material. In the composite material, the manufacturing process may be controlled in order to more efficiently perform the complexation between the polymer component and the material having a melting point in the predetermined range.

The manufacturing method comprises the steps of preparing a polymer composition by mixing a polymer and a material having a melting point in the range of 35° C. to 100° C. at a temperature higher than the melting point of the material, and complexing the prepared polymer composition with the metal foam. may include

As described above, by mixing the polymer and a material having a predetermined melting point at a temperature higher than the melting point of the material, and then complexing it with a metal foam, a composite material having desired physical properties can be effectively manufactured. The range of the mixing temperature applied in the above step is not particularly limited as long as the temperature is higher than the melting point of the material, but for proper complexation, the difference between the mixing temperature and the melting point of the material is within the range of 3°C to 50°C. can be controlled as much as possible. The difference may be a value obtained by subtracting the melting point from the mixing temperature. In another example, the difference is at least 5°C, at least 7°C, at least 9°C, at least 11°C, at least 13°C, at least 15°C, or at least 17°C, or at most 48°C, at most 46°C, at most 44°C, at most 42°C. , 40 °C or lower, 38 °C or lower, 36 °C or lower, 34 °C or lower, 32 °C or lower, 30 °C or lower, 28 °C or lower, 26 °C or lower, 24 °C or lower, 22 °C or lower, 20 °C or lower, 18 °C or lower, 16 It may be about °C or less, 14 °C or less, or 12 °C or less. When the mixing temperature is maintained in this range, a composite material having desired physical properties can be more effectively provided.

The mixing time is not limited as long as it is within a range in which suitable mixing can be achieved, and may be adjusted to an appropriate level according to the method of mixing.

The type of the polymer and the material applied in the mixing step is not particularly limited, and the polymer described in the above-mentioned polymer component and the material described above may be applied. In addition, other components such as the thermally conductive filler described above in the above step may be additionally mixed.

On the other hand, the method of complexing the polymer composition and the metal foam in the complexing step is not particularly limited. For example, a method of applying the polymer composition on the metal foam or immersing the metal foam in the polymer composition may be applied. . If necessary, the step of removing unnecessary excess polymer composition after applying the polymer composition to the metal foam may be additionally performed.

In addition, the metal foam in the above step may also be applied to the metal foam having the above-described characteristics (porosity, pore size and / or thickness, etc.).

The complexing step may include, for example, curing the polymer composition in a state in which the polymer composition is present at least on the surface of the metal foam. may also exist.

In the above, curing is a process in which the polymer composition is hardened by a chemical and/or physical reaction, and a method for performing such curing is not particularly limited, and a suitable method may be applied depending on the type of the polymer composition.

In the present application, a composite material that has excellent thermal conductivity, has excellent mechanical properties such as impact resistance, and can effectively realize thermal contact even in a very narrow space can be provided, and the composite material has close thermal contact even with a heavily stepped surface can be achieved

Hereinafter, the present application will be specifically described through Examples and Comparative Examples, but the scope of the present application is not limited to the following Examples.

Preparation Example 1.

Copper (Cu) powder having an average particle diameter (D50 particle diameter) in the range of about 10 to 20 μm was used as a metal component. In a mixture of terpineol and polyvinyl acetate (PVAc) in a 4:5 weight ratio (terpineol:PVAc), the copper powder was mixed with the binder (polyvinyl acetate) and copper powder in a ratio of about 10:1 A slurry was prepared by mixing in a weight ratio (Cu:PVAc). The slurry was coated in a film form and dried at about 120° C. for about 1 hour to form a metal foam precursor. Copper foam was prepared by applying an external heat source in an electric furnace to sinter the precursor so that the precursor was maintained at a temperature of about 1000° C. in a hydrogen/argon gas atmosphere for 2 hours. The porosity of the prepared film-type copper foam was about 70%, and the thickness was about 180 μm. The prepared copper foam was pressed to form a film having a thickness of about 100 μm, and then used for manufacturing a composite material. The porosity of the copper foam after pressing was about 45%.

Example 1.

As a polymer precursor to form the polymer component, a two-component thermosetting polymer composition was used. The two-component thermosetting polymer composition is composed of a main part (product name: sylgard527A: manufacturer: Dow) and a curing agent part (product name: sylgard527B, manufacturer: Dow), and is cured to a silicone polymer (glass transition temperature: about -130°C to - 120° C., melting point: about -50° C. to -40° C.

Solid paraffin wax (melting point: about 52° C. to 58° C.) was added to each of the main part and the curing agent part to a concentration of about 10% by weight (that is, the concentration of paraffin wax in the main part and the concentration of paraffin wax in the curing agent part were 10% by weight each) After that, the main part and the curing agent part were respectively heated to a temperature of about 70° C., and then each was mixed with a high-speed stirring to form a uniform solution.

A polymer composition was prepared by mixing the main part and the curing agent part in a weight ratio of 1:1 at room temperature.

Then, the copper metal foam of Preparation Example 1 was impregnated with the polymer composition, and the excess composition was removed using an applicator so that the thickness of the final composite material was about 120 μm. Then, the composite was prepared by curing the polymer composition by maintaining the above in an oven at about 100° C. for about 30 minutes. As a result of calculation based on the density and weight of the applied material in the composite material prepared as described above, the ratio (MV/PV) of the volume (PV) of the polymer component to the volume (MV) of the metal foam was about 0.8.

Example 2.

After mixing the thermal conductive filler (powder of spherical alumina (average particle diameter: about 2 μm)) to a concentration of about 20% by weight in each of the main part and the curing agent part before mixing the solid paraffin wax (that is, the amount of filler in the main part) The concentration and the concentration of the filler in the curing agent part are each 20% by weight), and again solid paraffin wax (melting point: about 52°C to 58°C is added to a concentration of about 10% by weight (that is, the main part containing the filler) A composite material was prepared in the same manner as in Example 1, except that the concentration of paraffin wax in the paraffin wax and the concentration of paraffin wax in the curing agent part including the filler were each 10 wt%). The ratio (MV/PV) of the volume (PV) of the metal foam to the volume (MV) of the metal foam was about 0.8. In addition, the particle diameter of the thermally conductive filler was the particle diameter (median diameter, D50) at 50% cumulative by volume of the particle size distribution. particle size), which is the particle diameter at the point where the cumulative value becomes 50% on the cumulative curve that calculates the particle size distribution on a volume basis and assumes the total volume is 100% The D50 particle diameter can be measured by the laser diffraction method there is.

Example 3.

After mixing the thermally conductive filler (powder of spherical alumina (average particle diameter: about 10 μm)) to a concentration of about 20% by weight in each of the main part and the curing agent part before mixing the solid paraffin wax (that is, the amount of filler in the main part) The concentration and the concentration of the filler in the curing agent part are each 20% by weight), and again solid paraffin wax (melting point: about 52°C to 58°C is added to a concentration of about 15% by weight (i.e., the main part containing the filler) A composite material was prepared in the same manner as in Example 1, except that the concentration of paraffin wax in the paraffin wax and the concentration of paraffin wax in the curing agent part including the filler were each 15 wt%). The ratio (MV/PV) of the volume (PV) of the metal foam to the volume (MV) of the metal foam was about 0.8. In addition, the particle diameter of the thermally conductive filler was the particle diameter (median diameter, D50) at 50% cumulative by volume of the particle size distribution. particle size), which is the particle diameter at the point where the cumulative value becomes 50% on the cumulative curve that calculates the particle size distribution on a volume basis and assumes the total volume is 100% The D50 particle diameter can be measured by the laser diffraction method there is.

Comparative Example 1.

A composite material was prepared in the same manner as in Example 1, except that solid paraffin wax was not applied.

Comparative Example 2.

Mixing the thermally conductive filler (powder of spherical alumina (average particle diameter: about 2 μm)) to a concentration of about 20% by weight in each of the main part and the curing agent part (that is, the concentration of the filler in the main part and the concentration of the filler in the curing agent part) A composite material was prepared in the same manner as in Example 1, except that 40 wt% of each) was used without applying solid paraffin wax. In addition, the particle size of the thermally conductive filler is the particle diameter (median diameter, D50 particle diameter) at 50% of the volume basis of the particle size distribution, and the particle size distribution is obtained on the volume basis, It is the particle diameter at the point where is 50%. The D50 particle size may be measured by a laser diffraction method.

Specimens were prepared using the composite materials prepared in each of Examples and Comparative Examples, and the thermal resistance thereof was evaluated. The specimen was prepared by cutting the composite material into a circular shape with a diameter of about 3.3 cm with a cutter. Thermal resistance was evaluated according to the standards of ASTM5470 using TIMtester (measured at 20 psi, 60°C conditions). The results are shown in Table 1 below.

Thermal resistance (Kin ² /W) Example 1 0.093 Example 2 0.069 Example 3 0.063 Comparative Example 1 0.110 Comparative Example 2 0.086

Claims (20)

Metal foam having a film form, a thickness of 1,000 μm or less, and a porosity of 85% or less;
a polymer component present on the surface of the metal foam; and
A composite material comprising a material present in the polymer component and having a melting point in the range of 35°C to 100°C. The composite material according to claim 1, wherein the polymer component is present on the surface of the metal foam and inside the metal foam. The composite material according to claim 1, wherein the ratio (T/MT) of the thickness (MT) to the total thickness (T) of the metal foam is 2.5 or less. The composite material according to claim 1, wherein the ratio (T/MT) of the thickness (MT) to the total thickness (T) of the metal foam is greater than 1. The composite material according to claim 1, wherein the metal foam includes a metal or a metal alloy having a thermal conductivity of 8 W/mK or more. The thermally conductive composite material according to claim 1, wherein the metal foam has a thickness of 10 μm or more. According to claim 1, wherein the metal foam, copper, gold, silver, aluminum, nickel, iron, cobalt, magnesium, molybdenum, any one metal selected from the group consisting of tungsten and zinc, or a skeleton comprising two or more of the above Composite with The composite material according to claim 1, wherein the polymer component has a glass transition temperature within the range of -300°C to 0°C or a melting temperature within the range of -100°C to 0°C. The composite material according to claim 1, wherein the ratio (MV/PV) of the volume (PV) of the polymer component and the volume (MV) of the metal foam is 10 or less. The composite material according to claim 1, wherein the material having a melting point in the range of 35°C to 100°C is a hydrocarbon compound, a fatty acid compound, a polyol compound, a high molecular compound, or an inorganic hydrate. The composite material according to claim 1, wherein the material having a melting point in the range of 35°C to 100°C is included in the range of 5 to 40 parts by weight based on 100 parts by weight of the polymer component. According to claim 1, wherein the ratio (MV / PV) of the volume (PV) of the polymer component to the volume (MV) of the metal foam is 10 or less, and the material having a melting point in the range of 35 °C to 100 °C is 100 parts by weight of the polymer component Composite material included in the range of 5 to 40 parts by weight compared to. The composite of claim 1 , further comprising a thermally conductive filler present in the polymer component. The composite material according to claim 13, wherein the thermally conductive filler is a ceramic filler or a carbon filler. The composite material according to claim 13, wherein the thermally conductive filler is included in an amount of 10 to 250 parts by weight based on 100 parts by weight of the polymer component. The method according to claim 13, wherein the ratio (MV/PV) of the volume (PV) of the polymer component to the volume (MV) of the metal foam is 10 or less, and the thermally conductive filler is in the range of 15 to 50 parts by weight based on 100 parts by weight of the polymer component. Including, the material having a melting point in the range of 35 ℃ to 100 ℃ is a composite material included in the range of 5 to 40 parts by weight based on 100 parts by weight of the polymer component. preparing a polymer composition by mixing a polymer and a material having a melting point in the range of 35°C to 100°C at a temperature higher than or equal to the melting point of the material having a melting point in the range of 35°C to 100°C; and compounding the polymer composition with a metal foam having a film shape, a thickness of 1,000 μm or less, and a porosity of 85% or less. The method of claim 17, wherein the difference between the mixing temperature and the melting point of the material having a melting point in the range of 35°C to 100°C in the mixing step of preparing the polymer composition is in the range of 3°C to 50°C. The method of claim 17 , wherein the step of complexing comprises curing the polymer composition in a state in which the polymer composition is present at least on the surface of the metal foam. The method of claim 19, wherein the polymer composition is also present inside the metal foam in the curing step.