KR20230044832A - Heat dissipation and flame retardant PDMS composite including carbon coated with metal hydroxide and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a heat dissipation and flame retardant PDMS composite including a metal hydroxide-coated carbon body. The heat dissipation and flame retardant PDMS composite is based on polydimethylsiloxane (PDMS) and includes a metal hydroxide-coated carbon body as a filler, thereby significantly improving heat dissipation and flame retardant effect.

Description

Heat dissipation and flame retardant PDMS composite including carbon coated with metal hydroxide and manufacturing method thereof}

The present invention relates to a PDMS composite for heat dissipation/flame retardance including a metal hydroxide-coated carbon body, and includes a polydimethylsiloxane (PDMS) base material as a metal hydroxide-coated carbon body as a filler to improve heat dissipation performance according to thermal conductivity. It relates to a PDMS composite for heat dissipation / flame retardancy including a carbon body coated with a metal hydroxide that improves flame retardancy as well as improved flame retardancy.

Recently, electronic devices used in automobiles, electric/electronic fields, etc. are becoming lighter, thinner, smaller, and more functional. Due to the high integration of electronic devices, the amount of heat generated in electronic component circuits increases, and the internal temperature of electronic devices rises, resulting in malfunction of semiconductor devices. , a change in the characteristics of a resistive component, a decrease in performance due to an increase in operating temperature, and a destruction of a printed circuit board due to repeated thermal expansion, etc.

In order to solve these problems, various technologies are being applied, and in particular, research is being conducted to effectively dissipate heat generated inside electronic products to the outside by increasing the thermal conductivity of polymer composites that make up most of the packages used in electronic products. It is being done.

A heat-dissipating polymer composite is a material that improves the thermal conductivity of the final material through the efficient formation of a heat transfer path by filling a large amount of thermally conductive filler in a resin component (substrate) with low thermal conductivity, thereby increasing the heat dissipation effect. As a heat dissipation polymer composite, a carbon-based filler such as graphite, carbon fiber, carbon nanotube, and graphene having excellent thermal conductivity, a ceramic-based filler such as boron nitride (BN), aluminum nitride (AIN), and alumina may be used alone or It is prepared by mixing, uniformly dispersing and highly filling in a polymer substrate.

The heat-dissipating polymer composite prepared in this way can be used to lower the temperature of electronic devices and electric vehicle batteries in automobiles, electric/electronic fields, and the like. However, in recent years, more various physical properties are required in addition to these heat dissipation properties, and moreover, in the case of automobile batteries, not only heat generation but also flame retardancy are required. represents performance.

For example, Korean Patent Registration No. 10-1218508 (2013.01.03: publication date) relates to a ceramic-carbon composite and a method for manufacturing the same, and manufactures a composite coated with oxide ceramic through a functional group or a coupling agent on a carbon body And, the composite discloses that it has thermal conductivity and electrical insulation, and Korean Patent Registration No. 10-1603582 (2016.03.16: Publication date) relates to a thermal diffusion sheet using a low-stiffness layer containing a ceramic-carbon composite, and graphite It is disclosed that a heat diffusion function and a battery insulation function can be realized by including a low-stiffness composite resin layer including an oxide ceramic-coated composite and a metal heat dissipation layer made of a thermally conductive metal through a functional group or a coupling agent.

However, in all of the prior literature, the material coated on the carbon body is an oxide, and ceramics, which are oxides, exhibit heat dissipation performance but do not have chemical properties that can prevent combustion, so graphite coated with ceramics cannot exhibit flame retardant performance. -Carbon composites cannot be applied to fields requiring flame retardancy.

Therefore, in order to solve this problem, as a material having heat dissipation and flame retardancy, metal hydroxide is being applied.

For example, Japanese Patent Publication No. 2021-014513 (published date: 2021.02.12.) discloses aluminum hydroxide and/or magnesium hydroxide or hollow ceramic beads and/or expanded graphite as components of the flame retardant resin composition, and is registered in Korea. Patent No. 10-2183631 (registration date: 2020.11.20.) discloses a flame retardant graphene-based composite fiber having flame retardancy by combining inorganic metal hydroxide on the surface of graphene oxide or reduced material.

On the other hand, polydimethylsiloxane (PDMS) is a material used in various fields such as a silicone foam stabilizer for manufacturing polyurethane foam for construction, a substrate for a protective film for a display, or a substrate for a thin film constituting an electrode, and has heat dissipation and flame retardancy. When used as a substrate in a required field, a separate heat dissipating agent and flame retardant are included. This is because, in the case of PDMS, it is known to exhibit flame retardancy by forming amorphous silica (SiO ₂ ) on the surface of the polymer that is burned during thermal decomposition because it contains Si-O bonds in the structure, but the flame retardance by the amorphous silica This is because it can be maintained for a very short time and cannot be used only with PDMS itself in practical use fields that must have heat dissipation and flame retardancy.

In order to impart heat dissipation and flame retardancy to the PDMS, it may be considered to fill the PDMS with a metal hydroxide. However, in this case, there is a problem in that thermal stability is not improved because PDMS is decomposed by a hydrolysis reaction during the bonding process of PDMS and metal hydroxide when high temperature heat is applied.

Therefore, the inventors of the present invention have studied repeatedly to impart heat dissipation and flame retardancy to PDMS while improving the problems of the prior art. The present invention was completed by discovering that it is possible to significantly improve heat dissipation and flame retardancy by metal hydroxide as well as preventing.

Korean Patent Registration No. 10-1218508 (2013.01.03: Publication Date) Korean Patent Registration No. 10-1603582 (2016.03.16: Publication Date) Japanese Laid-open Patent No. 2021-014513 (published date: 2021.02.12.) Korean Registered Patent No. 10-2183631 (registration date: 2020.11.20.)

In order to improve the heat dissipation and flame retardancy of polydimethylsiloxane (PDMS), the present invention includes a metal hydroxide and a carbon body having flame retardancy and heat dissipation performance as a heat dissipation and flame retardant, but in order to significantly improve their flame retardancy and heat dissipation performance, An object of the present invention is to provide a PDMS composite for heat dissipation/flame retardancy including a carbon body coated with a metal hydroxide, characterized in that the metal hydroxide is dispersed in polydimethylsiloxane (PDMS) in the form of a coating on the carbon body.

In addition, an object of the present invention is to provide a method for manufacturing a PDMS composite for heat dissipation/flame retardation including a carbon body coated with metal hydroxide.

In order to solve the above problems, the present invention is a PDMS composite for heat dissipation / flame retardancy including a metal hydroxide-coated carbon body, characterized in that it includes a metal hydroxide-coated carbon body as a filler, based on polydimethylsiloxane to provide.

In one embodiment of the present invention, the composite may include 20 to 60 parts by weight of a filler in 100 parts by weight of PDMS, and the carbon body coated with the metal hydroxide contains 15 to 40 parts by weight of the metal hydroxide per 100 parts by weight of the carbon body. It may be coated in parts by weight.

In one embodiment of the present invention, the metal hydroxide is at least one selected from the group consisting of magnesium hydroxide, aluminum hydroxide, and zinc hydroxide, and the carbon body is graphite, expandable graphite, and expandable graphite. It may be at least one selected from the group consisting of graphite, graphene, carbon fiber, carbon nano fiber, and carbon nano tube (CNTs).

In addition, the present invention (a) a hydroxyl group or a carboxyl functional group on the surface of the carbon body; at least one coupling agent selected from a silane coupling agent, a titanate coupling agent, and a zirconia coupling agent; and polymers having N-alkyl or N,N-dialkylamide groups; preparing a surface-modified carbon body by introducing any one or more surface modifiers selected from; (b) preparing a metal hydroxide-coated carbon body by adding a metal hydroxide precursor to the surface-modified carbon body; and (c) adding the metal hydroxide-coated carbon body as a filler to a polydimethylsiloxane (PDMS) substrate. A method for preparing the composite is provided.

In the step (a), a surface modifier may be introduced to the surface of the carbon body in an acidic solution having a pH of 6 or less, and in step (b), the surface-modified carbon body and the metal hydroxide precursor may be introduced into the surface of the carbon body at a pH of 7 or higher including a basic catalyst. By reacting in a solution, a metal hydroxide may be coated on the surface of the carbon body.

The present invention includes, as a filler, a carbon body coated with a metal hydroxide having heat dissipation and flame retardancy on a PDMS substrate, so as to impart heat dissipation performance and flame retardancy to PDMS in a flame or high-temperature environment. Therefore, it can be applied to various fields such as automobiles and electrical/electronic fields that require heat dissipation and flame retardancy.

1 shows a flow chart for producing metal hydroxide-coated graphite according to an embodiment of the present invention.
2 is a SEM image of graphite coated with Mg(OH) ₂ according to an embodiment of the present invention.
3 is a TGA analysis graph of graphite coated with Mg(OH) ₂ prepared according to an embodiment of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is one well known and commonly used in the art.

When it is said that a certain part "includes" a certain component throughout this specification, it means that it may further include other components, not excluding other components unless otherwise stated.

Heat dissipation means dissipation or effective discharge of heat to the outside, flame retardancy means a property that does not burn easily, delays ignition, and prevents the expansion of combustion. The present invention is a metal hydroxide having heat radiation and / or flame retardancy. And a carbon body, wherein the metal hydroxide is filled in a PDMS substrate in the form of a coating on the carbon body, thereby significantly improving the heat dissipation and flame retardant performance of the PDMS, heat dissipation including a carbon filler coated with a metal hydroxide / It is about flame retardant PDMS composite.

Hereinafter, the present invention will be described in detail.

In one aspect, the present invention is based on polydimethylsiloxane (PDMS), and includes a metal hydroxide-coated carbon body as a filler. provides a complex.

In the present invention, the substrate is polydimethylsiloxane (PDMS), which is used in various fields such as a silicone foam stabilizer for manufacturing polyurethane foam for construction, a substrate for a protective film for a display, or a substrate for a thin film constituting an electrode. It is known to exhibit flame retardancy by forming amorphous silica (SiO ₂ ) on the surface of the polymer, which contains a Si-O bond on the surface and burns during thermal decomposition. However, since the flame retardancy of the amorphous silica can be maintained for a very short time, it is necessary to include a filler having such characteristics in order to actually use PDMS as a material having heat dissipation and flame retardancy.

Therefore, the present invention includes a metal hydroxide-coated carbon body as a filler, and the filler is included in 20 to 60 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the PDMS. When in the above range, heat dissipation and flame retardant performance by the flame retardant are sufficiently exhibited.

Specifically, the metal hydroxide-coated carbon body may be coated with 15 to 40 parts by weight of the metal hydroxide per 100 parts by weight of the carbon body. When the content of the carbon body is within the above range, the flame retardant effect is greatest. More specifically, the metal hydroxide is at least one selected from the group consisting of magnesium hydroxide (Mg(OH) ₂ ), aluminum hydroxide (Al ₂ (OH) ₃ ) and zinc hydroxide (Zn(OH) ₂ ), wherein the The carbon body has a size of 10 nm to 1000 μm, and includes graphite, expandable graphite, expanded graphite, graphene, carbon fiber, and carbon nanofiber. Nano Fiber) and at least one selected from the group consisting of carbon nanotubes (CNTs).

The composite according to the present invention includes a metal hydroxide and a carbon body having heat dissipation and flame retardancy, but the metal hydroxide is coated on the carbon body and significantly improves heat dissipation and flame retardancy performance as the PDMS is filled, and the sheet resistance is 10 ⁸ to 10 ¹⁴ Ω/sq, thermal conductivity of 0.6 to 0.78, and ignition time of 51 to 60 seconds in an ignition test conducted with a gas torch.

In another aspect of the present invention, step (a) is a hydroxyl group or carboxyl functional group on the surface of the carbon body; at least one coupling agent selected from a silane coupling agent, a titanate coupling agent, and a zirconia coupling agent; and polymers having N-alkyl or N,N-dialkylamide groups; preparing a surface-modified carbon body by introducing any one or more surface modifiers selected from; (b) preparing a metal hydroxide-coated carbon body by adding a metal hydroxide precursor to the surface-modified carbon body; and (c) adding the metal hydroxide-coated carbon body as a filler to a polydimethylsiloxane (PDMS) substrate. A method for preparing the composite is provided.

In the present invention, steps (a) and (b) are steps for preparing a metal hydroxide-coated carbon body, and correspond to FIG. 1.

Referring to Figure 1, step (a) is a hydroxyl group or carboxyl functional group on the surface of the carbon body; at least one coupling agent selected from a silane coupling agent, a titanate coupling agent, and a zirconia coupling agent; and polymers having N-alkyl or N,N-dialkylamide groups; This is a step of preparing a surface-modified carbon body by introducing one or more surface modifiers selected from among them.

The carbon body includes graphite, expandable graphite, expanded graphite, graphene, carbon fiber, carbon nano fiber, and carbon nanotube ( At least one selected from the group consisting of (CNTs), since the carbon body exhibits hydrophobicity without functional groups on the surface, it is difficult to disperse in an aqueous solution and difficult to coat the metal hydroxide on the surface, and it is difficult to coat the metal hydroxide on the surface of the carbon body. Even if the hydroxide is coated, pores on the surface of the carbon body have a fatal effect on thermal conductivity. Therefore, a surface modification step of introducing a functional group to the surface of the carbon body is required.

Therefore, in the step (a), a hydroxyl group or a carboxyl functional group on the surface of the carbon body; at least one coupling agent selected from a silane coupling agent, a titanate coupling agent, and a zirconia coupling agent; and polymers having N-alkyl or N,N-dialkylamide groups; The surface of the carbon body is modified through chemical bonding or physical bonding by introducing any one or more surface modifiers selected from among.

There are three major methods of chemical modification of the surface of the carbon body. The first is a method of introducing a hydroxyl group into a carbon body in a high-temperature acidic solution. In this method, the structure of the carbon body is destroyed and there is a risk of loss of excellent properties of the carbon body. The second method is to introduce a functional group to the surface of the carbon body using a phase transfer catalyst. A carbon body dispersed in an organic solvent and an oxidizing agent dissolved in water are mixed, and ions are generated at the interface between the two solutions by the phase transfer catalyst. After generating a functional group by a nucleophilic substitution reaction on the surface of the carbon body by allowing transfer to occur, a coupling agent is introduced into the surface-modified carbon body. The third is a method of introducing a coupling agent by introducing a carbonaceous material into an aqueous solution of a weak acid, and one or more of the above coupling agents may be used.

Preferably, the surface of the carbon body is chemically modified by the second or third method, and in one embodiment, the modification of the carbon body through chemical bonding is carried out in an acidic solution of pH 6 or less, a hydroxyl group on the surface of the carbon body, The surface of the carbon body may be modified by introducing a carboxyl group or a coupling agent, or by further introducing a coupling agent after introducing a hydroxyl group or a carboxyl group to the surface of the carbon body.

In this case, the coupling agent is at least one selected from a silane coupling agent, a titanate coupling agent, and a zirconia coupling agent, specifically, the silane coupling agent is aminoethyl aminopropyl triethoxy silane, aminopropyl trimethoxy silane, Aminopropyl triethoxy silane, aminoethyl aminopropyl methyl dimethoxy silane, phenyl triethoxy silane, tetraethyl ortho silicate, diethoxydimethyl silane, phenyl aminopropyl trimethoxy silane and aminoethyl aminopropyl trimethoxy It may be at least one selected from the group consisting of silanes, and the titanate coupling agent is isopropyl tridioctylphosphate titanate, isopropyl trioleyl titanate, isopropyl tristearyl titanate, isoso It may be at least one selected from the group consisting of propyl tri dodecylbenzenesulfonate titanate, isopropyl tridioctylpigophosphate titanate, and tetraisopropyl didioctylphosphate titanate, and the zirconia coupling agent is zirconium. Conium IV, 2,2bis-2-prophenoletomethyl butenoleto trisdioctylpyrophosphate-O, and zirconium 1,1bis-2-prophenoletomethyl butanoleto tris 2-amino It may be any one or more selected from the group consisting of phenyleto.

In addition, the surface of the carbon body may be modified by a physical method.

In one embodiment, the surface of the carbon body may be modified by a polymer having an N-alkyl or N,N-dialkyl amide group. Specifically, when a polymer having an N-alkyl or N,N-dialkyl amide group is dissolved in water or an alcohol solution, and then a carbon body is added and stirred, the polymer chain having the N-alkyl or N,N-dialkyl amide group is dissolved. In this case, the hydrophobic portion covers the surface of the carbon body and the hydrophilic portion faces out of the solution to form a network of polymer chains, so that the polymer coupling agent is strongly physically adsorbed on the surface of the carbon body, and thus the carbon body can form a hydrogen bond. be in a state of being able to

At this time, the polymer having the N-alkyl or N, N-dialkyl amide group is poly (N-acetylethyleneimine), poly (2-methyl-2-oxazoline), poly (N, N-dimethylacrylamide) and poly At least one selected from the group consisting of (N-vinylpyrrolidone), which may be used singly or in a mixed form of two or more, and the polymer has a molecular weight controlled according to the size of the carbon body, so that the carbon body has a large size. The higher the molecular weight, the higher the molecular weight is used, and the alcohol may be any one or more selected from methanol, ethanol, propanol, butanol, acetone, toluene, dimethylformamide and xylene, but is not limited thereto.

Next, step (b) of the present invention is a step of preparing a carbon body coated with a metal hydroxide by a sol-gel method by adding a metal hydroxide precursor to the surface-modified carbon body.

The sol-gel method may be performed using a stover method, which is a common method, or under different conditions, but preferably, a metal hydroxide precursor is added to a solution of pH 7 or higher containing the surface-modified carbon body and a catalyst and mixed After that, a polymerization reaction is performed to synthesize a metal hydroxide on the surface of the carbon body. At this time, the polymerization temperature may be 15 to 80 ° C., and the reaction time may be adjusted according to the content and temperature of the metal hydroxide precursor and the surface-modified carbon body. In one embodiment, in a solution condition of pH 7 or higher at a polymerization temperature of 15 to 80 ° C., for 5 minutes or more, preferably 5 minutes to 3 hours, metal hydroxide is synthesized / coated on the surface of the carbon body, or in another embodiment, micro The metal hydroxide may be synthesized and coated on the surface of the carbon body by reacting at a polymerization temperature of 30 to 80 ° C. for 1 minute or more, preferably 5 to 10 minutes in a wave oven.

At this time, the metal hydroxide precursor is any one or more magnesium precursors selected from the group consisting of magnesium nitrate, magnesium acetate tetrahydrate and magnesium methoxide; Any one or more aluminum precursors selected from the group consisting of aluminum nitrate, aluminum isopropoxide and aluminum sec butoxide; and a zinc oxide precursor which is zinc nitrate, zinc acetate or a mixture thereof; It may be any one or more selected from, and the catalyst is ammonium hydroxide, tetrapropyl ammonium chloride, tetrapropyl ammonium hydroxide, potassium hydroxide, tetrabutylammonium bromide, tetrabutylammonium chloride and tetrabutylammonium hydroxide It may be any one or more basic catalysts selected from the group consisting of sides.

Also at this time, the metal hydroxide precursor is added in an amount of 15 to 40 parts by weight based on 100 parts by weight of the carbon body. This is because when the metal hydroxide is included in less than 15 parts by weight, the heat dissipation and flame retardant performance effect by the metal hydroxide is insignificant, and when it exceeds 40 parts by weight, the degree of effect improvement is not large compared to the added metal hydroxide content, so the economic efficiency is lowered and the carbon body A large amount of uncoated unbonded metal hydroxide may be present, which may rather deteriorate heat dissipation and flame retardancy effects.

In the present invention, step (c) is a step of adding the metal hydroxide-coated carbon body as a filler to a polydimethylsiloxane (PDMS) substrate, based on 100 parts by weight of the PDMS substrate. The sieve is added as a filler in an amount of 20 to 60 parts by weight, preferably 30 to 50 parts by weight. If less than 20 parts by weight of the filler is included, flame retardancy and heat dissipation performance may deteriorate, and if it exceeds 60 parts by weight, the degree of improvement in effect is not large compared to the content of the added filler, reducing economic feasibility and rather unbonding that is not bonded to the substrate. There is a concern that physical properties may be deteriorated due to the presence of an excessive amount of fillers.

Hereinafter, examples will be described for more specific explanation of the present invention. However, the following examples are only preferred examples of the present invention and the present invention is not limited to the following examples.

1. Synthesis of Electrically Insulating and Thermally Conductive Fillers

fillers 1 to 4

After introducing and dissolving 2.5 to 5 g of polyethylene glycol (hereinafter referred to as “PEG”) in 600 g of ethanol at room temperature, 50 g of graphite was added and stirred for 1 hour, and then 20 to 40 g of MgCl ₂ was added at room temperature and nitrogen atmosphere. After stirring for 1 hour, 33 to 67 g of aqueous ammonia solution (25-30%) was added.

Thereafter, after stirring for 3 hours, graphite coated with magnesium hydroxide was prepared through _filtering and drying processes. It was prepared with fillers 1 to 4 as described above.

filler 5

After introducing and dissolving 5 g of Polyethylene Glycol (hereinafter referred to as "PEG") in 600 g of ethanol at room temperature, 50 g of graphite was added and stirred for 1 hour, and then 40 g of AlCl ₃ was added at room temperature and nitrogen atmosphere and stirred for 1 hour. Then 67 g of aqueous ammonia solution (25-30%) was added.

After stirring for 3 hours, graphite coated with aluminum hydroxide was prepared through filtering and drying processes.

filler 6

After introducing and dissolving 5 g of Polyethylene Glycol (hereinafter referred to as “PEG”) in 600 g of ethanol at room temperature, 50 g of graphite was added and stirred for 1 hour, and then 40 g of ZnCl ₂ was added at room temperature and nitrogen atmosphere and stirred for 1 hour. Then 67 g of aqueous ammonia solution (25-30%) were added.

Then, after stirring for 3 hours, graphite coated with zinc hydroxide was prepared through filtering and drying processes.

filler 7

After adding 50 g of graphite to 600 g of ethanol at room temperature and stirring for 1 hour, 40 g of MgCl ₂ was added at room temperature and nitrogen atmosphere, followed by stirring for 1 hour, and then 67 g of aqueous ammonia solution (25-30%) was added. After stirring for 3 hours, magnesium hydroxide-graphite was prepared through filtering and drying processes.

filler 8

After introducing and dissolving 5 g of polyethylene glycol (hereinafter “PEG”) in 600 g of ethanol at room temperature, 50 g of graphite was added and stirred for 1 hour, then 40 g of MgCl ₂ was added at room temperature and nitrogen atmosphere, and stirred for 3 hours. After filtering and drying, Filler 8 was prepared.

Fillers 9 to 11

For comparison, a mixture of 50 g of graphite and 40 g of Mg(OH) ₂ (filler 9), only Mg(OH) ₂ (filler 10), or only graphite (filler 11) was used as a filler.

Manufacturing conditions and the content of each component of the filler are shown in Table 1 below.

In addition, the sheet resistance of the fillers 1 to 11 was measured and shown according to ASTM D 257.

2. Filler analysis

(1) SEM and EDX analysis

In order to analyze the surface shape and constituent elements of the prepared filler 3, SEM (Scanning Electron Microscope) and EDX (Energy Dispersive X-ray Spectroscopy) analyzes were performed, and the results are shown in FIG. 2 and Table 2.

FIG. 2 is a SEM photograph showing filler 3 coated with magnesium hydroxide on graphite magnified 2,000 times and 50,000 times. It can be seen that the original graphite surface has a wide plate shape, but the graphite coated with magnesium hydroxide has several coating layers on the surface. there is.

division wt(%) At (%) C 63.29 79.34 O 29.07 18.46 Mg 3.98 2.13

(2) TGA analysis

In the prepared filler 3, in order to confirm the form of magnesium coated on graphite, TGA analysis was performed and shown in FIG. 3, at which time, commercially available Mg(OH) ₂ was used as a control.

According to FIG. 3, both filler 3 and control Mg(OH) ₂ release H ₂ O by thermal decomposition upon TGA analysis, indicating that the material coated on graphite in filler 3 is magnesium hydroxide Mg(OH) ₂ .

<Experimental Example 1> PDMS composite flame retardancy evaluation according to the type of filler

As shown in Table 3 below, 40 wt% of the filler and 60 wt% of the type 2 liquid PDMS (Dow, Sylgard 184) were kneaded using a mixer for 10 minutes at room temperature and press-molded at 120 ° C. for 10 minutes to prepare an electrically insulating high thermal conductivity resin. Next, sheet resistance and thermal conductivity (horizontal direction) were measured according to ASTM E1461 according to ASTM D257 with respect to the prepared electrical insulating high thermal conductivity resin composition introduced with the filler.

The thermal conductivity and sheet resistance measurement results of the polymer composite into which the prepared filler was introduced are shown in Table 2 below along with the composition. The flame retardancy of the composite was checked by placing a 10 cm x 10 cm x 2 T specimen at a distance of 10 cm from the gas torch and igniting the torch, then igniting the specimen.

Table 3 shows the ignition time and thermal conductivity of PDMS only using PDMS as a polymer resin and not using fillers 1 to 11 and fillers. Examples 1 to 6, in which MgCl ₂ , AlCl ₃ , and ZnCl ₂ were added as precursors of the filler, and ammonia was also added so that the precursors were converted into hydroxides, the ignition time exceeded at least 50 seconds, so that the flame retardance was reduced to any Comparative Example 6, which did not contain a filler, showed a very short ignition time, and the same amount of graphite, MgCl ₂ and PEG as in Example 3 was used, but no ammonia water was added, so it was not converted to Mg (OH) ₂ It can be confirmed that the smoke time is short even in the case of Comparative Example 2 (filler 8) maintaining the form of MgCl ₂ .

<Experimental Example 2> Epoxy composite flame retardancy evaluation according to the type of filler

In order to examine the effect of the filler in the case of using other polymer resins instead of PDMS in Experimental Example 1, 50 wt% of the two-type liquid epoxy (EPONS) and 50 wt% of the filler were kneaded for 10 minutes at room temperature using a mixer and mixed at 60 degrees for 30 minutes. An electrically insulating high thermal conductivity resin was prepared by press molding for a minute. Then, as in Experimental Example 1, thermal conductivity, sheet resistance, and ignition time were measured and listed in Table 4 below.

Table 4 shows the results of constructing and testing composites using epoxy instead of PDMS in order to show the effect of using other polymers instead of PDMS. In the case of epoxy, since the flame retardancy is lower than that of PDMS, a composite was prepared by further increasing the content of the filler to 50 wt%.

When epoxy, not PDMS, is used as the polymer to which the filler is mixed, filler 10 consisting of only Mg(OH) ₂ without graphite is compared to Comparative Example 7 using filler 6 in which graphite is coated with Mg(OH) ₂ . In the case of Comparative Example 9, which was used, the ignition time was found to be slower, which is opposite to the results in Table 3.

From this, it can be confirmed that the filler of the present invention, in which graphite particles are coated with metal hydroxide, exhibits an effect as a flame retardant in the PDMS-based composite.

Having described specific parts of the present invention in detail above, it will be clear to those skilled in the art that these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby. will be. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (7)

A PDMS composite for heat dissipation/flame retardancy including a metal hydroxide-coated carbon body, characterized in that it includes a metal hydroxide-coated carbon body as a filler, based on polydimethylsiloxane (PDMS).
According to claim 1,
The composite is a PDMS composite for heat dissipation / flame retardancy including a metal hydroxide-coated carbon body, characterized in that it comprises 20 to 60 parts by weight of a filler in 100 parts by weight of PDMS.
According to claim 1,
The metal hydroxide-coated carbon body is a PDMS composite for heat dissipation / flame retardancy including a metal hydroxide-coated carbon body, characterized in that the metal hydroxide is coated in 15 to 40 parts by weight with 100 parts by weight of the carbon body.
According to claim 1,
The metal hydroxide is at least one selected from the group consisting of magnesium hydroxide, aluminum hydroxide and zinc hydroxide,
The carbon body includes graphite, expandable graphite, expanded graphite, graphene, carbon fiber, carbon nano fiber, and carbon nanotube ( A PDMS composite for heat dissipation / flame retardancy including a carbon body coated with a metal hydroxide, characterized in that at least one selected from the group consisting of CNTs).
(a) a hydroxyl or carboxyl functional group on the surface of a carbon body; at least one coupling agent selected from a silane coupling agent, a titanate coupling agent, and a zirconia coupling agent; and polymers having N-alkyl or N,N-dialkylamide groups; preparing a surface-modified carbon body by introducing any one or more surface modifiers selected from;
(b) preparing a metal hydroxide-coated carbon body by adding a metal hydroxide precursor to the surface-modified carbon body; and
(c) adding the metal hydroxide-coated carbon body as a filler to a polydimethylsiloxane (PDMS) substrate; heat dissipation/flame retardant PDMS composite including a metal hydroxide-coated carbon body Manufacturing method of.
According to claim 5,
Method for producing a PDMS composite for heat dissipation / flame retardancy including a metal hydroxide-coated carbon body, characterized in that in the step (a), a surface modifier is introduced to the surface of the carbon body in an acidic solution of pH 6 or less.
According to claim 5,
In the step (b), the surface-modified carbon body and the metal hydroxide precursor are reacted in a solution containing a basic catalyst having a pH of 7 or higher to coat the surface of the carbon body with the metal hydroxide. A method for producing a PDMS composite for heat dissipation/flame retardancy including a sieve.

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