KR101549986B1 - Composition for complex sheet, complex sheet comprising the same, and preparation method of the complex sheet - Google Patents

Abstract

The present invention relates to a core-shell type filler particle comprising a magnetic particle having a thermally conductive ceramic compound formed on its surface; And a curable curable organic binder, a composite sheet comprising the core-shell type filler particles, and a method for producing the composite sheet. According to such a composition for a composite sheet, Thermal conductivity and electromagnetic wave absorption performance can be realized, and the hardness of the final composite sheet can be lowered even in the same filler content.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for a composite sheet comprising core-shell type filler particles, a composite sheet comprising the same and a method for producing the composite sheet,

The present invention relates to a composition for a composite sheet, a composite sheet comprising the composite sheet, and a method for producing the composite sheet. More particularly, the present invention relates to a composite sheet, And an electromagnetic wave absorbing property at the same time, a composite sheet comprising the same, and a process for producing the composite sheet.

The present invention has been derived from research carried out as part of the industrial technology development project of the Ministry of Knowledge Economy [Project Number: 10031944, Title: Development of heat spread type electromagnetic wave suppression for protecting LCD devices].

Recently, electronic devices and electronic parts tend to become thinner and thinner, so that the degree of integration of electric devices is increasing, and the amount of heat generated by electric devices operating with electric energy is also greatly increasing. Accordingly, there is a growing demand for improvement in heat dissipation characteristics that effectively dissipates the heat generated in the electronic device and dissipates it. Also, as the degree of integration of electric devices increases, the amount of generated electromagnetic waves also increases. Such electromagnetic waves leak through joints and joints of electronic devices to cause malfunction of other electric devices or electronic parts, or weaken the human immune function There was a problem of harmful action.

As a result, various studies have been made on a heat dissipation characteristic for effectively dispersing and dissipating the heat generated from the electric element, and a characteristic capable of effectively shielding and absorbing the electromagnetic wave that causes malfunction of the electric element and adversely affects the human body .

There has been proposed a method in which a heat radiating plate which conveys heat to radiate heat to the outside or a silicone rubber sheet which is excellent in thermal conductivity or the like is proposed in order to improve heat dissipation characteristics of various electric elements, It has a problem that it is difficult to firmly adhere to the electrodes and the heat dissipation characteristics can not be sufficiently exhibited and there is almost no ability to shield and absorb electromagnetic waves.

Accordingly, methods have been proposed in which a material having heat dissipation properties and a material for shielding and absorbing electromagnetic waves are applied together. Particularly, a product obtained by laminating a sheet having a heat conductive property and a sheet having an electromagnetic wave shielding / absorbing property is often used. Such products are thicker due to the characteristics of a multilayered material, It has been difficult to realize the thermal conductivity and the electromagnetic wave absorption characteristics to the extent required by the above. In order to improve the thermal conductivity or the electromagnetic wave absorption property, a method of increasing the filling amount of the filler added to the multi-layer material has been proposed. However, due to compatibility and the like, it is difficult to fill the filler more than a certain amount, The hardness of the multi-layer material increases and the heat conduction characteristic of the product is lowered.

Although the use of a composite sheet in which an existing heat conductive material and an electromagnetic wave suppressing material are integrated is attempted, it is not easy to sufficiently secure two types of heat conduction performance and electromagnetic wave suppression performance, and it is insufficient to be commercialized in various products. Particularly, there is a technical problem that it is difficult to sufficiently secure the electromagnetic wave suppression performance when securing the heat conduction performance to about 5 W / mK or so. Accordingly, various researches and developments have been made on methods capable of improving both the heat conduction performance and the electromagnetic wave suppressing performance at the same time.

Korean Patent Publication No. 2006-0106638 Korean Patent Publication No. 2009-0033586

The present invention is to provide a composition for a composite sheet capable of simultaneously enhancing both heat conductivity and electromagnetic wave absorptivity without deteriorating withstand voltage strength while maintaining magnetic properties and thermal conductivity characteristics while simultaneously providing electrical insulation.

The present invention also provides a composite sheet comprising the composition for a composite sheet.

The present invention relates to a core-shell type filler particle including a core including magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound; And a curable organic binder, wherein the core-shell type filler particles have different average particle sizes of two or more different groups.

The present invention also provides a composite sheet comprising the thermosetting composition of the composite sheet composition.

The present invention also relates to an organic binder cured on a sheet; And a core-shell type filler particle dispersed in the organic binder sheet and including a core including magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound, wherein the core- The core-shell type filler particles provide a composite sheet having an average particle size of two or more different groups.

Hereinafter, the composition for a composite sheet and the composite sheet according to a specific embodiment of the present invention will be described in detail.

In the specification of the present invention, 'filler' refers to a material that is filled to give specific properties to the composite sheet such as heat conductivity or electromagnetic wave absorption performance, and 'core-shell type'Quot; means a material surrounding the material forming the core (or core).

According to an embodiment of the present invention, a core-shell type filler particle including a core including magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound; And a curable organic binder, wherein the core-shell type filler particles have different average particle diameters of two or more groups.

The present inventors have found that when two or more kinds of core-shell type filler particles having a core containing magnetic particles and a shell layer formed on the core and containing a thermally conductive ceramic compound are used with different average particle diameters, It has been confirmed through experiments that the electrical insulation property of the filler can be maintained and the electrical insulation property can be maintained while maintaining the magnetic property and the thermal conductivity property and both the heat conduction characteristics and the electromagnetic wave absorption performance can be improved without lowering the withstand voltage strength. Completed.

The 'groups having two or more different average particle diameters' means a state in which the average particle diameters of the core-shell type filler particles are distributed in different ranges and can be classified into different kinds. For example, it may mean that the average particle size of the core-shell type filler particles shows two or more peaks that can be distinguished from the normal distribution curve.

Specifically, the average particle size of the core-shell type filler particles may be a D50 value measured by a laser particle size analyzer, and the particle size distribution of the filler particles may be a normal distribution The particle diameter of the core-shell type filler particle can be set to D50 which is a value of 50% cumulative size (the size of the area under the normal distribution graph) based on the largest value in the particle size distribution.

The composite sheet is prepared by mixing two or more kinds of core-shell type filler particles with different average particle diameters into a curable organic binder. Thus, core-shell type filler particles having an average particle diameter range Both the heat conduction characteristics and the electromagnetic wave absorption performance can be improved at the same time without lowering the withstand voltage strength.

That is, when the core-shell type filler particles having an average particle size range of Group 1 were used, either the heat conduction characteristics or the electromagnetic wave absorption performance could be improved, but there was a certain limit in improving both of them. On the contrary, by using the two groups of core-shell type filler particles having different average particle size distributions, the core-shell type filler particles in the organic binder can achieve the best chargeability with higher compatibility have. Can be a larger complex action than the sum of the anticipated effects when two groups of core-shell type filler particles having different average particle size distributions are used, respectively.

The specific average particle diameter of the core-shell type filler particles having different average particle diameters of the two or more groups may be determined by calculating the respective powder sizes capable of achieving closest packing. For example, if the average particle size of the first group of core-shell type filler particles is set to about 50 占 퐉, the gap between the first group of core-shell type filler particles Another group of fillable core-shell type filler particles that can be filled can be set to about 20 탆, and another group of core-shell type filler particles The average particle diameter can be set to about 10 mu m.

Specifically, at least one of the core-shell type filler particles may have an average particle size of 40 to 80 占 퐉 or an average particle size of 45 to 60 占 퐉. Since at least one of the core-shell type filler particles has an average particle size within the above-mentioned range, even if the amount of the filler to be filled is greatly increased, not only the hardness is not so much increased but also the relatively thin It is possible to realize excellent heat conduction characteristics, electromagnetic wave absorption performance, and withstanding voltage strength even with a single layer structure having a thickness.

In addition, one of the core-shell type filler particles may have an average particle diameter of 1 占 퐉 to 20 占 퐉. That is, the filler particles of the core-shell type filler particles having an average particle diameter of 40 탆 to 80 탆 and one kind of core-shell type filler particles have a particle diameter of 1 탆 to 20 탆 Mu m or an average particle diameter of 5 mu m to 15 mu m.

At least one of the core-shell type filler particles has an average particle diameter of 40 to 80 탆 and the other one has an average particle diameter of 1 to 20 탆, The filler particles can achieve optimum chargeability with higher compatibility.

Meanwhile, the core-shell type filler particles have a core-shell type filler particle having an average particle diameter of 40 to 80 탆 and a core-shell type filler particle having an average particle diameter of 10 to 20 탆. - It can be included in a larger amount than the core-shell type filler particles.

Specifically, a core-shell type filler particle having an average particle diameter of 40 탆 to 80 탆: a weight ratio between core-shell type filler particles having an average particle diameter of 10 탆 to 20 탆 May be from 8: 2 to 5: 5, or from 7: 3 to 5.5: 4.5, or from 6.5: 3.5 to 5.5: 4.5.

On the other hand, the unique action or effect of the composition for a composite sheet appears to be due to the inherent characteristics of the core-shell type filler particles. The filler particles of the core-shell type can not only realize properties from the material constituting the core and the material constituting the shell, but also can be used for the core- A composite effect of two or more substances can be realized.

Accordingly, when a core-shell type filler particle including a core including the magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound is applied, the high thermal conductivity of the filler Characteristics and electromagnetic wave absorptive performance of the composite sheet, and the hardness of the composite sheet, which is the final product, is low, thereby reducing the thermal resistance when applied to electronic parts, thereby maximizing the heat conduction characteristics. In addition, when the core-shell type filler particles are used, the hardness of the composite sheet is not significantly increased even if the amount of filler to be filled in the composite sheet is greatly increased. In addition, It is possible to realize excellent heat conduction characteristics, electromagnetic wave absorption performance, and withstanding voltage strength even with a composite sheet of a single layer.

The composite synergistic effect of using two or more core-shell type filler particles having different average particle diameters is as described above.

The core-shell type filler particles may include a core including the magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound. That is, the core-shell type filler particles may be in the form of a shell of the thermally conductive ceramic compound surrounding the core of the magnetic particles, and the thermally conductive compound may be bonded to the surface of the magnetic particles through physical or chemical bonding have.

The magnetic particles may include soft magnetic metal alloy particles or ferrite magnetic particles. The soft magnetic metal alloy particles may include a metal alloy that can be quickly magnetized when a magnetic field is applied from the outside, and can realize an action or effect of absorbing and removing electromagnetic noise of a specific frequency on the composite sheet. Specific examples of such magnetic particles include iron-silicon-aluminum alloys, iron-silicon alloys, iron-chromium-silicon alloys, iron-chromium alloys, nickel-iron alloys, carbonyl iron, mixtures thereof, have. The ferrite magnetic particles may include a material having a spinel structure that is easily magnetized to an external magnetic field as a ceramic material. Specific examples thereof include nickel-zinc ferrite, manganese-zinc ferrite, a mixture thereof, .

There is no particular limitation on the shape of the magnetic particles, and may be, for example, a shape such as a sphere, a circle, a plate, a polyhedron, or a rotating body. In addition, although there is no particular limitation on the size of the magnetic particles, it is preferable to use magnetic particles having an average particle size (D50) of 1 to 100 mu m in order to easily produce a composite sheet or a core- In order to uniformly disperse the filler particles in a high content.

Accordingly, it is preferable that the magnetic particles include at least one of iron-silicon-aluminum alloy, iron-silicon alloy, iron-chromium-silicon alloy, iron- And mixtures thereof.

The thermally conductive ceramic compound can be used in a composite sheet to exert an action or effect of rapidly transferring heat generated in an electric element or the like to a heat sink. Specific examples of the thermally conductive ceramic compound include alumina (Al ₂ O ₃ ), boron nitride (BN), aluminum nitride (AlN), silicon carbide (SiC), magnesium oxide (MgO), zinc oxide (ZnO) (OH) ₃ ), or a mixture thereof. The thermally conductive ceramic compound can be formed on the surface of the magnetic particles with a thickness of 0.1 to 10 mu m by the manufacturing method described below.

The curable organic binder may serve as a base of the composite sheet, and it is preferable to use a material having excellent heat radiation properties and impact absorption properties. Specific examples of materials usable for such organic binders include thermosetting silicone rubber compounds, one-component thermosetting silicone binders, two-component thermosetting silicone binders, acrylic resins, epoxy resins, urethane resins or mixtures thereof, It is not necessary to provide a separate adhesive layer due to its excellent adhesive force, so that the work fixing can be simplified and the production cost of the final product can be reduced.

The composition for a composite sheet comprises 1 to 99% by weight of the core-shell type filler particles; And 1 to 99% by weight of a curable organic binder. As the core-shell type filler particles are applied, the compatibility with the organic binder can be improved and the volume content (volume%) of the ceramic filler required to realize the same thermal conductivity can be lowered. Therefore, Can be greatly increased. Accordingly, the composition for a composite sheet comprises 50 to 99% by weight of the core-shell type filler particles; And 1 to 50% by weight of a curable organic binder, more preferably 70 to 95% by weight of the core-shell type filler particles; And 5 to 30% by weight of a curable organic binder.

Meanwhile, the composition for a composite sheet may further comprise magnetic particles, thermally conductive ceramic compound particles, or a mixture thereof. The magnetic particles or the thermally conductive ceramic compound particles are distinguished from the thermally conductive ceramic compound and the magnetic particles included in the core-shell type filler particles. The magnetic particles or the thermally conductive ceramic compound particles are used as an additional filler for improving the thermal conductivity or electromagnetic wave absorption performance of the composite sheet. Lt; / RTI > The magnetic particles or the thermally conductive ceramic compound particles to be added as an additional filler can exert the effect of additionally improving the heat conduction characteristics and the electromagnetic wave absorption characteristics.

Accordingly, the composition for a composite sheet comprises 1 to 97% by weight of the core-shell type filler particles; 1 to 70% by weight of the curable organic binder; And 1 to 90% by weight of the magnetic particles or the thermally conductive ceramic compound particles. As described above, when the filler particles of the core-shell type are applied, the filling amount of the filler can be greatly increased. Therefore, the composition for the composite sheet comprises 45 to 97% by weight of the core-shell type filler particles; 1 to 50% by weight of the curable organic binder; And 1 to 50% by weight of the magnetic particles or the thermally conductive ceramic compound particles. More preferably, the composition for a composite sheet comprises 70 to 95% by weight of the core-shell type filler particles; 1 to 25% by weight of the curable organic binder; And 1 to 25% by weight of the magnetic particles or the thermally conductive ceramic compound particles.

The composition for a composite sheet may further contain additives such as a heat stabilizer, a UV stabilizer, a crosslinking agent, or a pigment. The amount of such additives to be used can be appropriately adjusted in consideration of the properties of the final product.

On the other hand, according to another embodiment of the invention, a composite sheet comprising a thermosetting composition of the above composition for a composite sheet can be provided.

When the composition for a composite sheet is applied or formed in a sheet form and then heated, the organic binder contained in the composition for a composite sheet is cured to form the base of the sheet, and the core-shell type Filler particles can be dispersed in the organic binder sheet.

In the above-mentioned step of thermosetting the composition for a composite sheet, the composition for a composite sheet described above can be thermally cured at 50 ° C to 250 ° C for 10 to 2 hours.

The components contained in the composite sheet may include all of the components included in the composition for a composite sheet described above. The specific effects and actions of the composite sheet may also include all of the contents of the composition for a composite sheet described above.

The composite sheet may have a thickness of 0.1 to 10.0 mm. If the thickness of the composite sheet is too thin, it is difficult to realize proper heat conduction characteristics and electromagnetic wave absorption performance. If the thickness is too large, the heat resistance increases and the performance of the composite sheet may be reduced by half. Which is not preferable in terms of weight saving.

According to another embodiment of the present invention, an organic binder cured on a sheet; And a core-shell type filler particle dispersed in the organic binder sheet and including a core including magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound, wherein the core- The core-shell type filler particles may be provided with a composite sheet having an average particle diameter of two or more different groups.

As described above, the composite sheet containing the core-shell type filler particles dispersed in the organic binder sheet has a problem that not only the hardness is increased so much even if the amount of the filler to be filled is greatly increased, Excellent heat conduction characteristics, electromagnetic wave absorption performance and withstand voltage strength can be realized even with a single layer structure having a relatively thin thickness.

Particularly, in the composite sheet, the electrical insulation of the filler is ensured, thereby maintaining both the magnetic property and the heat conduction characteristic, and at the same time, the electrical insulation can be provided, thereby improving both the heat conduction characteristic and the electromagnetic wave absorption performance without lowering the withstand voltage strength.

The composite sheet may have a thickness of 0.1 to 10.0 mm. If the thickness of the composite sheet is too thin, it is difficult to realize proper heat conduction characteristics and electromagnetic wave absorption performance. If the thickness is too large, the heat resistance increases and the performance of the composite sheet may be reduced by half. Which is not preferable in terms of weight saving.

Also, the composite sheet has a Asker C hardness of 10 to 30 hardness, preferably Asker C hardness of 15 to 28 in the thickness range; A thermal conductivity of 4 to 6.0 W / mK, preferably 4.5 to 6.0 W / mK, more preferably 4.8 to 6.0 W / mK; 5.0 * 10 ¹¹ to 5.0 * 10 ¹³ Ω · m volume resistance; And a withstand voltage strength of 2.0 to 5.0 kV / mm, preferably 2.5 to 4.0 kV / mm.

The composite sheet may be a single layer sheet having a thickness of 0.1 to 10.0 mm. Generally, when the hardness of the heat-radiating sheet is high, air may be present between the heat sink and the interface of the heat-generating component, thereby increasing the contact heat resistance and decreasing the heat radiation characteristics. It is possible to realize an excellent heat dissipation characteristic because the hardness is not so high.

The composite sheet may further include magnetic particles, a thermally conductive ceramic compound, or a mixture thereof dispersed in the organic binder sheet. As described above, the magnetic particles, the thermally conductive ceramic compound particles, or the mixture thereof, which are further included, are distinguished from the thermally conductive ceramic compound and the magnetic particles included in the core-shell type filler particles, Or as an additional filler for improving electromagnetic wave absorption performance. The magnetic particles, the thermally conductive ceramic compound, or the mixture thereof may be dispersed on the organic binder sheet.

Accordingly, the composite sheet comprises 1 to 97% by weight of core-shell type filler particles dispersed in the organic binder sheet; 1 to 70% by weight of an organic binder cured on a sheet; And 1 to 90% by weight of the magnetic particles, the thermally conductive ceramic compound particles, or a mixture thereof.

As described above, when the core-shell type filler particles are applied, the filling amount of the filler can be greatly increased. Therefore, the composite sheet comprises 45 to 97% by weight of the core-shell type filler particles; 1 to 50% by weight of organic binder; And 1 to 50% by weight of the magnetic particles, the thermally conductive ceramic compound particles, or a mixture thereof. More preferably, the composite sheet comprises 70 to 95% by weight of the core-shell type filler particles; 1 to 25% by weight of organic binder; And 1 to 25% by weight of the magnetic particles, the thermally conductive ceramic compound particles, or a mixture thereof.

The constituent elements that can be included in the composite sheet have already been described in connection with the composition for a composite sheet, and the detailed description thereof will be omitted.

On the other hand, the composite sheet includes a first step of forming core-shell type filler particles including a core including magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound; Mixing the core-shell type filler particles and the organic binder having different average particle sizes of the two or more groups formed in the first step; And molding the mixture into a sheet form.

The forming of the core-shell type filler particles comprises: mixing the thermally conductive ceramic compound and the magnetic particles; And applying a shear stress and an impact force to the mixture. When the shear stress and the impact force are applied to the mixture of the thermally conductive ceramic compound and the magnetic particles as described above, the core-shell type filler particles can be produced in a short time according to the step, Process time can be easily controlled, and an eco-friendly process can be constructed in which an organic solvent is used in the manufacturing process or a harmful substance is not generated.

There is no particular limitation on the method of applying the shear stress and impact force to the mixture of the thermally conductive ceramic compound and the magnetic particles, the time and the magnitude of the applied shear stress and the impact force, but the thermally conductive ceramic compound may be uniformly formed It is preferable to apply shear stress and impact force for 5 minutes to 1 hour at a shear rate of 3,000 rpm to 10,000 rpm. There is no particular limitation on the method and apparatus for applying shear stress and impact force, but it is preferable to use a high-speed mixer, a Henschel mixer, or a super mixer.

The size ratio of the magnetic particles to the thermally conductive ceramic compound in the mixture may be from 5: 1 to 250: 1. When the size ratio of the magnetic particles: thermoconductive ceramic compound is 5: 1 or less, the remaining amount of the particles of the thermally conductive ceramic compound not bonded or coated on the magnetic particles becomes large, and the filling amount of the composite sheet may be lowered . If the size of the magnetic particles is excessively larger than the size of the particles of the thermally conductive ceramic compound, the frequency of the magnetic particles colliding with each other during the formation of the core-shell type filler particles increases, It may be difficult to easily coat the surface of the magnetic particles.

Meanwhile, mixing the core-shell type filler particles and the organic binder may further include adding magnetic particles or thermally conductive ceramic compound particles. As described above, the additionally added magnetic particles or thermally conductive ceramic compound particles are distinguished from the thermally conductive ceramic compound and the magnetic particles contained in the core-shell type filler particles, and the thermal conductivity or the electromagnetic wave absorption performance Can be added as an additional filler to improve the strength of the film.

The step of mixing the core-shell type filler particles and the organic binder may further include adding additives such as a heat stabilizer, a UV stabilizer, a crosslinking agent, or a pigment. The amount of such additives to be used can be appropriately adjusted in consideration of the properties of the final product.

In the step of forming the mixture of the core-shell type filler particles and the organic binder into a sheet form, various molding methods may be used without any particular limitation, but the molding method such as hot pressing, tape casting, vacuum extrusion, It is preferable to use a vacuum casting method or a spray coating method. The step of shaping the mixture into a sheet form may include curing the sheet obtained from the mixture at 50 DEG C to 250 DEG C for 10 to 2 hours.

On the other hand, in the above-described method for producing a composite sheet, a step of post-curing the sheet obtained from the mixture at 100 or more for 3 hours or more to lower the content of the low molecular weight siloxane compound of D3-D10 . When the sheet obtained from the mixture is post-cured in a high-temperature vacuum oven for a long time, the content of the low molecular weight siloxane compound of D3-D10 can be greatly lowered.

The materials used in the method for producing the composite sheet and the like have already been described in connection with the composition for a composite sheet, and the detailed description thereof will be omitted.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a composite sheet composition capable of simultaneously improving both heat conductivity and electromagnetic wave absorption performance without deteriorating withstand voltage strength, while maintaining magnetic properties and thermal conductivity characteristics while simultaneously providing electrical insulation; A method of manufacturing a sheet can be provided.

1 schematically shows a composite sheet of an embodiment of the invention.
Fig. 2 is a SEM photograph of the core-shell type particles obtained in Production Example 1. Fig.
Fig. 3 is a SEM photograph of the core-shell type particles obtained in Production Example 2. Fig.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

< Manufacturing example : Core-shell ( Core - Shell ) Type filler  Preparation of particles &gt;

Production Example 1

The Fe-Cr powder and the alumina powder as the thermally conductive ceramic material were charged into the chamber and subjected to a shear force and an impact force at room temperature for 30 minutes at a rate of 8,000 rpm to prepare an Fe-Cr particle powder About 50 탆] was obtained

Production Example 2

The Fe-Si powder and the alumina powder as the thermally conductive ceramic material were charged into the chamber and subjected to a shear force and an impact force at room temperature for 30 minutes at a speed of 8,000 rpm to obtain an Fe-Si particle powder About 10 [mu] m] was obtained

Production Example 3

The Fe-Cr powder and the alumina powder as the thermally conductive ceramic material were charged into the chamber and subjected to a shear force and an impact force at room temperature for 30 minutes at a rate of 8,000 rpm to prepare an Fe-Cr particle powder About 10 [mu] m] was obtained

< Example  And Comparative Example : Production of composite sheet>

Example 1  To 4 and Comparative Example 1

The core-shell type filler particles, ceramic powder and organic binder obtained in Preparation Examples 1 to 4 were mixed at a composition ratio shown in Table 1 at 10 캜 for 120 minutes by a planetary mixing method. Then, the mixture was made into a sheet having a thickness of 2.0 mm by tape casting, and the prepared sheet was cured at 150 캜 for 30 minutes.

The specific names and contents of the components used in Examples 1 to 4 and Comparative Examples are as shown in Table 1 below.

Composition of composite sheet division Core shell powder Ceramic powder content (wt%) Organic binder
Content (wt%) Mixing weight ratio Content (wt%) Example 1 Fe-Cr (50 占 퐉): Fe-Si (10 占 퐉) = 7: 3
85 Alumina
5 silicon
10 Example 2 Fe-Cr (50 占 퐉): Fe-Si (10 占 퐉) = 6: 4
85 Alumina
5 silicon
10 Example 3 Fe-Cr (50 占 퐉): Fe-Si (10 占 퐉) = 5: 5 85 Alumina
5 silicon
10 Example 4 Fe-Cr (50 占 퐉): Fe-Cr (10 占 퐉) = 6: 4 85 Alumina
5 silicon
10 Comparative Example 1 Fe-Cr (50 탆) 90 0 silicon
10

In Table 1, SL-5100 manufactured by Korea KCC Co., Ltd. was used as the silicon organic binder.

Comparative Example 2

75% by weight of Ni-Zn ferrite, 10% by weight of alumina and 15% by weight of silicon were mixed by a planetary mixing method at 10 캜 for 120 minutes. A 2.0 mm sheet was obtained from this mixture by tape casting.

Comparative Example 3

88% by weight of Fe-Al-Si, 2% by weight of alumina and 10% by weight of silicon, which are soft magnetic metal alloys, were mixed by a planetary mixing method at 10 DEG C for 120 minutes. A 2.0 mm sheet was obtained from this mixture by tape casting.

The specific names and contents of the components used in Comparative Examples 2 and 3 are as shown in Table 2 below.

The composition of the composite sheet of Comparative Examples 2 and 3 Magnetic powder
(wt%) Thermoconductive ceramic powder (wt%) Organic binder
(wt%) Comparative Example 2 Ni-Zn ferrite (75) Alumina (10) Silicon (15) Comparative Example 3 Fe-Al-Si (88) Alumina (2) Silicon (10)

In Table 2, SL-5100 manufactured by Korea KCC Co., Ltd. was used as the silicon organic binder.

< Experimental Example >

The thermal conductivity (W / mK), the power loss (%), the volume resistance (? Cm), the hardness (Asker C) and the withstand voltage strength (kV / mm) of the composite sheet prepared in the above Examples and Comparative Examples were measured .

(1) The thermal conductivity was measured by a modified hot-wire method of ASTM E55 method using a TCi apparatus of C-Therm.

(2) Power loss was measured using Agilent E8357A network analyzer.

(3) Hardness measurement

A load of 1 kg was applied to a 5 cm x 5 cm specimen obtained from the composite sheet of Examples and Comparative Examples, and the hardness was measured using Asker C type hardness meter.

(4) Withstanding voltage strength

The withstand voltage strength of the composite sheet was measured using a Zentech 9027A withstand voltage tester.

The measurement results are shown in Table 3 below.

Measurement results of the experimental example division Thermal conductivity
(W / mK) Power loss
(%) Withstanding voltage strength
(kV / mm) Hardness
(Asker C) Example 1 5.0 39 3.2 23 Example 2 5.0 42 3.5 25 Example 3 4.5 35 3.1 27 Example 4 4.8 38 3.2 25 Comparative Example 1 5.0 30 0.2 30 Comparative Example 2 1.7 23 1.5 30 Comparative Example 3 2.3 30 0.2 35

As shown in Table 3 above, the composite sheet of the examples showed excellent thermal conductivity and electromagnetic wave absorbing ability while having Asker C hardness of less than 30. In addition, it exhibits a withstanding voltage strength of 3.0 kV / mm or more and can realize excellent characteristics as a heat dissipation material, exhibits a high thermal conductivity of 4.5 W / mK or more and a power loss of 35% or more and can simultaneously improve both heat conduction characteristics and electromagnetic wave absorption performance Respectively.

On the other hand, the composite sheet of Comparative Example 1 can have the same level of thermal conductivity, power loss, and hardness as those of the composite sheets of Examples 1 to 4, but the strength of the withstand voltage is low, There is a limitation in application to the field of supplying devices.

On the other hand, the composite sheet obtained in Comparative Examples 2 and 3 had a thermal conductivity of less than 2.5 W / mK, a sufficient withstand voltage strength and electromagnetic wave absorption capability, a Asker C hardness of 30 or more, It was confirmed that it was not possible.

1: Cured organic binder
2: First core-shell type filler particles
3: Second core-shell type filler particles
4: Ceramic powder

Claims (16)

A core-shell type filler particle including a core including magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound; And
And a curable organic binder,
The core-shell type filler particles have an average particle diameter of at least two different groups, and the average particle diameter is a D50 value measured by a laser particle size analyzer. Also, the core-shell type core- Wherein the average particle diameter of the filler particles of the composite sheet exhibits at least two peaks that can be distinguished from the normal distribution curve.
The method according to claim 1,
Wherein at least one of the core-shell type filler particles has an average particle diameter of 40 탆 to 80 탆.
3. The method of claim 2,
Wherein one of the core-shell type filler particles has an average particle diameter of 1 占 퐉 to 20 占 퐉.
The method of claim 3,
A core-shell type filler particle having an average particle diameter of 40 탆 to 80 탆 and a core-shell type filler particle having an average particle diameter of 10 탆 to 20 탆 in a weight ratio of 8: 3 to 5: 5.
The method according to claim 1,
Wherein the magnetic particles comprise soft magnetic metal alloy particles or ferrite magnetic particles.
The method according to claim 1,
Wherein the magnetic particles are selected from the group consisting of an iron-silicon-aluminum alloy, an iron-silicon alloy, an iron-chromium-silicon alloy, an iron-chromium alloy, a nickel-iron alloy, carbonyl iron, a nickel-zinc ferrite and a manganese- Wherein the composition comprises at least one selected from the group consisting of polyvinyl alcohol and polyvinyl alcohol.
The method according to claim 1,
The thermally conductive ceramic compound is alumina (Al ₂ O _3), boron nitride (BN), nitride aluminum (AlN), silicon carbide (SiC), magnesium oxide (MgO), zinc oxide (ZnO), and hydroxide of aluminum (Al (OH ) ₃ ). &Lt; / RTI &gt;
The method according to claim 1,
Wherein the curable organic binder comprises at least one member selected from the group consisting of a thermosetting silicone rubber compound, a one-component thermosetting silicone binder, a two-component thermosetting silicone binder, an acrylic resin, an epoxy resin and a urethane resin.
The method according to claim 1,
Magnetic particles, and thermally conductive ceramic compound particles.
10. The method of claim 9,
Wherein the magnetic particles or the thermally conductive ceramic compound particles have an average particle diameter of 0.1 占 퐉 to 10 占 퐉.
11. The method of claim 10,
1 to 97% by weight of the core-shell type filler particles;
1 to 70% by weight of the organic binder; And
And 1 to 90% by weight of at least one kind of particles selected from the group consisting of the magnetic particles and the thermally conductive ceramic compound particles.
A composite sheet comprising a thermosetting composition of the composition for a composite sheet according to any one of claims 1 to 11.
13. The method of claim 12,
A composite sheet having a thickness of 0.1 to 10.0 mm.
An organic binder cured on a sheet; And
A core-shell type filler particle dispersed in the organic binder sheet and including a core including magnetic particles and a shell layer formed on the core and including a thermally conductive ceramic compound,
The core-shell type filler particles have an average particle diameter of at least two different groups, and the average particle diameter is a D50 value measured by a laser particle size analyzer. Also, the core-shell type core- Characterized in that the average particle diameter of the filler particles of the composite sheet exhibits two or more peaks that can be distinguished from the normal distribution curve.
15. The method of claim 14,
A composite sheet having a thickness of 0.1 to 10.0 mm.
16. The method of claim 15,
The composite sheet further comprising at least one particle selected from the group consisting of magnetic particles and thermally conductive ceramic compound particles dispersed in the organic binder sheet.

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