JP7298615B2 - Composition, sheet and heat storage material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composition, a sheet and a heat storage material.

2. Description of the Related Art Conventionally, automobiles, buildings, air conditioners in underground malls, automobile engines, electronic parts, and the like are provided with heat storage materials for temporarily storing thermal energy and extracting the thermal energy at any time.

Examples of the heat storage material include materials that store heat or release heat using phase transition of substances. As such heat storage materials, for example, those using heat storage components such as saturated hydrocarbons, organic acids, and organic acid esters are known. These have excellent heat storage properties due to reversible phase transition. However, since these heat storage materials are in a liquid state on the high temperature side of the phase transition, there is a possibility that the heat storage component may ooze out, so some measure must be taken to prevent oozing out. Therefore, a composition using a polymer as a binder or a composition using a gelling agent has been proposed.

On the other hand, heat storage materials containing these heat storage components are effective in applications such as floor cooling and heating that require sustained heat dissipation, but due to low thermal conductivity, heat exchange with the heat storage material is difficult. In applications such as heat pipes, which require rapid processing, sufficient effects have not been exhibited. Therefore, until now, studies have been made on increasing the thermal conductivity of the heat storage material.

Patent Document 1 discloses the use of a composition containing high thermal conductivity fibers with an aspect ratio of 10 to 1500 as a heat storage material, and typical examples of high thermal conductivity fibers include metal fibers and carbon fibers. It is In Patent Document 1, among these, metal fibers are particularly preferred, and copper fibers and aluminum fibers are also used in the examples.

JP-A-5-163485

However, the density of the metal fiber used in Patent Document 1 is high, and if a large amount is added to the heat storage material, the heat storage capacity per mass is significantly reduced, so only a small amount can be added. That is, since the thermal conductivity and the heat storage capacity of the heat storage material are in a trade-off relationship, it is difficult to improve the heat conductivity while suppressing the decrease in the heat storage capacity.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a composition with improved thermal conductivity and suppressed reduction in heat storage capacity. Another object of the present invention is to provide a sheet and a heat storage material in which bleeding is suppressed.

The inventors of the present invention focused on carbon materials that have a lower density than metal fibers, and found that graphite contributes to the improvement of thermal conductivity. The present inventors have completed the present invention based on the finding that, compared to graphite, the thermal conductivity can be greatly improved and the decrease in heat storage capacity can be suppressed.

The present invention, in one aspect, is a composition containing a heat storage component and expanded graphite.

In this composition, the heat-storage component may be a saturated hydrocarbon. The heat storage component may be an organic acid ester. The heat storage component may be an acrylic resin.

The composition may further contain a copolymer of ethylene and an olefin having 3 or more carbon atoms. The olefin may have 3 to 8 carbon atoms. In this case, the composition may further contain at least one polyolefin selected from the group consisting of polyethylene and polypropylene.

The content of expanded graphite may be 15% by mass or more based on the total amount of the composition.

Another aspect of the present invention is a sheet comprising a heat storage layer containing the above composition. In this sheet, the thermal conductivity of the heat storage layer may be 0.5 W/mK or more.

Another aspect of the present invention is a heat storage material containing the above composition.

The present invention, in another aspect, is an article comprising a heat source and the above composition provided so as to be in thermal contact with the heat source.

ADVANTAGE OF THE INVENTION According to one aspect of the present invention, it is possible to provide a composition with improved thermal conductivity and suppressed decrease in heat storage capacity. Further, according to one aspect of the present invention, it is possible to provide a sheet and a heat storage material in which bleeding is suppressed.

1 is a schematic cross-sectional view showing an embodiment of a sheet; FIG. 1 is a schematic cross-sectional view showing an embodiment of an article provided with a heat storage material; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with appropriate reference to the drawings. In addition, this invention is not limited to the following embodiment.

As used herein, "(meth)acrylate" means "acrylate" and corresponding "methacrylate", and "(meth)acryloyl" means "acryloyl" and corresponding "methacryloyl".

A composition according to one embodiment contains a heat storage component (hereinafter also referred to as "(A) component") and expanded graphite (hereinafter also referred to as "(B) component").

The component (A) is a component having a heat storage property, for example, a component having a property of absorbing surrounding heat and storing it during phase transition from a solid state to a liquid state. Component (A) may be, for example, a compound having a melting point of 0 to 100°C. Such a compound undergoes a phase transition when changing from a temperature lower than the melting point to a temperature higher than the melting point in an environment of 0 to 100° C., which is a practical temperature range for a heat storage material. Therefore, the component (A) has heat storage properties in the temperature range, which is the practical range for the heat storage material. The component (A) can also be said to be a compound having a high heat storage capacity.

Component (A), in one embodiment, may be a saturated hydrocarbon. The saturated hydrocarbon is preferably a chain saturated hydrocarbon. As used herein, "chain" means linear or branched. The saturated hydrocarbons are preferably linear. The saturated hydrocarbon may have, for example, 10 or more, 12 or more, or 14 or more carbon atoms, and may be 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, or 16 or less.

Specific examples of saturated hydrocarbons include n-tetradecane (C14 (carbon number, hereinafter the same), 6° C. (melting point, hereinafter the same)), n-pentadecane (C15, 9° C.), n-hexadecane (C16, 18 ℃), n-heptadecane (C17, 21 ℃), n-octadecane (C18, 28 ℃), n-nanodecane (C19, 32 ℃), n-eicosane (C20, 37 ℃), n-henicosane (C21, 41 ° C), n-docosane (C22, 46 ° C), n-tricosane (C23, 47 ° C), n-tetracosane (C24, 50 ° C), n-pentacosane (C25, 54 ° C), n-hexacosane (C26, 56 ℃), n-heptacosane (C27, 60 ℃), n-octacosane (C28, 65 ℃), n-nonacosane (C29, 66 ℃), n-triacontane (C30, 67 ℃), n-tetracontane (C40 , 81° C.), n-pentacontane (C50, 91° C.), n-hexacontane (C60, 98° C.), and the like. The melting point of a saturated hydrocarbon is the melting (endothermic) of a thermogram obtained when heated at a temperature elevation rate of 10° C./min using a differential scanning calorimeter (for example, “8500” manufactured by PerkinElmer Co., Ltd.). It is the temperature at which the tangent to the maximum slope of the peak intersects the baseline.

The saturated hydrocarbon may be a petroleum wax whose main component is linear saturated hydrocarbon. Petroleum wax is a product separated and refined from vacuum distillation components of raw material petroleum or natural gas. Specific examples of petroleum wax include Paraffin Wax manufactured by Nippon Seiro Co., Ltd. (48 to 69° C. (melting point, hereinafter the same)), HNP (64 to 77° C.), SP (60 to 74° C.), EMW (49°C) and the like. These saturated hydrocarbons may be used alone or in combination of two or more.

The (A) component may be an organic acid ester in one embodiment. The organic acid ester may be linear or branched. Organic acid esters are preferably fatty acid esters. Fatty acid esters may be esters of fatty acids and fatty alcohols. The fatty alcohol may be, for example, a mono- to tri-hydric alcohol, preferably a mono-hydric alcohol. When the fatty alcohol is a polyhydric alcohol having a valence of 2 or more, the fatty acid ester may be a partial ester obtained by esterifying a part of the hydroxyl groups of the polyhydric alcohol, and all the hydroxyl groups of the polyhydric alcohol are esterified. It may also be a complete ester.

When the organic acid ester is an ester of a fatty acid and a fatty alcohol, the fatty acid may have 12 or more, 14 or more, or 16 or more carbon atoms, and may be 22 or less, 20 or less, or 18 or less. The number of carbon atoms in the aliphatic alcohol may be 1 or more, 22 or less, 15 or less, 10 or less, 5 or less, or 2 or less. Organic acid esters include methyl laurate (C12/C1 (carbon number of fatty acid/carbon number of aliphatic alcohol, hereinafter the same), 5°C (melting point, the same hereinafter)), ethyl myristate (C14/C2, 10°C). , ethyl palmitate (C16/C2, 20°C), butyl palmitate (C16/C4, 33°C), methyl stearate (C18/C1, 40°C), ethyl stearate (C18/C2, 34°C), stearin Butyl acid (C18/C4, 22°C), methyl arachidate (C20/C1, 48°C), methyl behenate (C22/C1, 52°C), glycerol monomyristate (C14/C3, 44-48°C), etc. can be These organic acid esters may be used singly or in combination of two or more.

(A) In one embodiment, the component may be an acrylic resin. The acrylic resin is preferably a polymer obtained by polymerizing a monomer component containing a first monomer and a second monomer.

式中、Ｒ^１は水素原子又はメチル基を表し、Ｒ^２は炭素数１２～３０のアルキル基を表す。The first monomer is preferably represented by the following formula (1).

In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 12-30 carbon atoms.

The alkyl group represented by ^R2 may be linear or branched. The number of carbon atoms in the alkyl group represented by R ² is preferably 12-28, more preferably 12-26, even more preferably 12-24, and particularly preferably 12-22.

The first monomer is, in other words, an alkyl (meth)acrylate having a linear or branched alkyl group having 12 to 30 carbon atoms at the end of the ester group. Examples of the first monomer include dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate), heptadecyl (meth) ) acrylate, octadecyl (meth) acrylate (stearyl (meth) acrylate), nonadecyl (meth) acrylate, eicosyl (meth) acrylate, henicosyl (meth) acrylate, docosyl (meth) acrylate (behenyl (meth) acrylate), tetracosyl (meth) acrylate ) acrylate, hexacosyl (meth)acrylate, octacosyl (meth)acrylate and the like. These 1st monomers are used individually by 1 type or in combination of 2 or more types.

The content of the first monomer is preferably 60 parts by mass or more, more preferably 70 parts by mass with respect to 100 parts by mass of the monomer component, from the viewpoint of obtaining a sufficient heat storage amount when forming the heat storage material. or more, more preferably 80 parts by mass or more, and may be, for example, 98 parts by mass or less.

The second monomer is a monomer copolymerizable with the first monomer and having a reactive group (reactive monomer). The second monomer contains a group having an ethylenically unsaturated bond (ethylenically unsaturated group) so as to be copolymerizable with the first monomer. Examples of ethylenically unsaturated groups include (meth)acryloyl groups, vinyl groups, and allyl groups. The second monomer is preferably a monomer having a reactive group and a (meth)acryloyl group (a (meth)acrylic monomer having a reactive group).

The reactive group in the second monomer is a group capable of reacting with a curing agent described later, for example, at least one group selected from the group consisting of a carboxyl group, a hydroxyl group, an isocyanate group, an amino group and an epoxy group. be. That is, the second monomer is, for example, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an isocyanate group-containing monomer, an amino group-containing monomer or an epoxy group-containing monomer. The epoxy group-containing monomer may be, for example, glycidyl (meth)acrylate.

The content of the second monomer may be 25 parts by mass or less, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 13 parts by mass or less, relative to 100 parts by mass of the monomer component. Particularly preferably, it is 10 parts by mass or less. The content of the second monomer may be 2 parts by mass or more with respect to 100 parts by mass of the monomer component.

The monomer component can further contain other monomers as necessary in addition to the first monomer and the second monomer. Other monomers, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate alkyl group having less than 12 carbon atoms (1 to 11 carbon atoms) of the ester group Alkyl (meth)acrylates having a terminal; cycloalkyl (meth)acrylates having a cyclic hydrocarbon group such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate at the terminal of an ester group; and the like. Other monomers are used singly or in combination of two or more.

Acrylic resins can be obtained by known polymerization methods such as various radical polymerizations using the monomer components described above. The polymerization method may be, for example, a suspension polymerization method, a solution polymerization method, a bulk polymerization method, or the like.

The content of component (A) is preferably 40% by mass or more, more preferably 45% by mass or more, and still more preferably 50% by mass or more, based on the total amount of the composition, from the viewpoint of further improving the heat storage effect. be. The content of component (A) may be 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less.

Expanded graphite (component (B)) is graphite expanded by inserting an intercalating substance between graphite layers. Since the bonds between graphite layers are weak bonds due to van der Waals forces, various compounds can be intercalated. When the intercalated material is removed by heating, the graphite expands, producing expanded graphite. Although the density of expanded graphite decreases due to expansion, it retains the high thermal conductivity that is the original feature of graphite, so it can be expected to have an excellent effect as an additive for increasing thermal conductivity in expanded graphite.

Since expanded graphite has a low density, a relatively large amount of expanded graphite can be added to the composition, which is effective in increasing the thermal conductivity of the composition. Moreover, since the bulk density of expanded graphite is low, the volume ratio per mass of the composition can be increased. In this case, the larger the particle size of the expanded graphite, the higher the probability of contact between the expanded graphite, and a small amount of addition can achieve high thermal conductivity of the composition.

Expanded graphite also includes so-called "expanded graphite pulverized powder" obtained by pulverizing graphite after expanding it. The pulverized expanded graphite powder is a powder obtained by rolling the expanded graphite obtained by the above-described method into a sheet, producing an expanded graphite sheet, and then pulverizing the sheet.

The expanded graphite may be in the form of particles such as flat particles. The particulate expanded graphite may be expanded graphite having an aspect ratio of less than 20. The aspect ratio is the ratio of the maximum length of the expanded graphite calculated from a scanning electron micrograph of the expanded graphite to the minimum length of the expanded graphite in the direction perpendicular to the direction of the maximum length (maximum length length/minimum length).

The average particle size of the expanded graphite is preferably 100 μm or more, more preferably 120 μm or more, and still more preferably 150 μm or more, from the viewpoint of increasing the contact probability between the expanded graphite and further increasing the thermal conductivity. . The average particle size of the expanded graphite is preferably 2000 µm or less, more preferably 1000 µm or less, and still more preferably 500 µm or less from the viewpoint of improving dispersibility and stabilizing properties. The average particle size of expanded graphite can be measured with a scanning electron microscope (SEM).

From the viewpoint of further improving the thermal conductivity of the composition, the content of component (B) is preferably 5% by mass or more, 10% by mass or more, 15% by mass or more, 17% by mass or more, based on the total amount of the composition. , or 20% by mass or more. The content of component (B) is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass, based on the total amount of the composition, from the viewpoint of further suppressing a decrease in heat storage capacity. % or less.

The composition may further contain a copolymer of ethylene and an olefin having 3 or more carbon atoms (hereinafter also referred to as "component (C)"). When the (A) component is a saturated hydrocarbon or an organic acid ester, the (C) component has a role as a binder. By using the component (C), it is possible to suppress the bleeding of the liquid from the composition even in the region above the melting point of the component (A), and the sheet produced using the composition (details will be described later) It is possible to improve the handling performance of.

When the component (A) is an acrylic resin, by imparting a cross-linking functional group to the component (C), it is possible to provide a composition that can retain its shape even at the melting point of the acrylic resin or higher. A cross-linking functional group can react with a reactive group possessed by an acrylic resin. The crosslinkable functional group is not particularly limited as long as it is a crosslinkable functional group, and may be at least one selected from a vinyl group, a (meth)acryloyl group, a glycidyl group, and an allyl group.

The olefin constituting component (C) has 3 or more carbon atoms. It is more preferably 3 to 10, still more preferably 3 to 8, from the viewpoint of easy availability and excellent affinity with the component (A). When the olefin has 4 or more carbon atoms, the olefin may be linear or branched. Component (C) may be composed of olefins having more than 8 carbon atoms as long as there is no problem with compatibility with component (A). Component (C) includes copolymers of ethylene and propylene (C3 (carbon number, hereinafter the same)), copolymers of ethylene and butene (C4), copolymers of ethylene and pentene (C5), Copolymer of ethylene and hexene (C6), copolymer of ethylene and heptene (C7), copolymer of ethylene and octene (C8), copolymer of ethylene and nonene (C9), ethylene and Copolymers with decene (C10) and the like are included. (C) A component is used individually by 1 type or in combination of 2 or more types.

The content of component (C), based on the total amount of the composition, may be 3% by mass or more, 5% by mass or more, or 7% by mass or more, and 35% by mass or less, 30% by mass or less, or 25% by mass or less. can be

When the composition contains component (C), the composition contains at least one polyolefin selected from the group consisting of polyethylene (ethylene homopolymer) and polypropylene (propylene homopolymer) (hereinafter referred to as "component (D) ”) may further be contained. Since component (D) can form a physical mutual network structure with component (A) and/or component (C), it suppresses the fluidity of the composition at high temperatures and forms the composition into a sheet. It is possible to make it easier to maintain the shape of the case. The melting point of component (D) may be, for example, 100° C. or higher. Component (D) may be a linear polymer, a branched polymer, or a polymer modified by various methods.

The content of component (D) may be 5% by mass or more, 7% by mass or more, or 10% by mass or more, and may be 20% by mass or less, 18% by mass or less, or 15% by mass or less, based on the total amount of the composition. can be

The composition may contain a gelling agent (hereinafter, also referred to as "(E) component") to further suppress liquid exudation. Component (E) includes at least one selected from carboxylic acid metal salts and carboxylic acids, and the addition of component (E) can further enhance the effect of suppressing fluidity.

A carboxylic acid metal salt is a salt of a carboxylic acid with a metal capable of forming a salt with the carboxylic acid. The carboxylic acid is not particularly limited, but from the viewpoint of compatibility with the component (A), it preferably has 5 or more carbon atoms, more preferably 7 or more carbon atoms, and still more preferably 10 or more carbon atoms. . Such carboxylic acids are, for example, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, docosahexaenoic acid, behenic acid, undecylenic acid, oleic acid, erucic acid, linoleic acid, arachidonic acid, linolenic acid, sabienoic acid. etc. Carboxylic acid is used individually or in combination of 2 or more types.

The metal may be aluminum, for example. Carboxylic acid metal salts may specifically be aluminum stearate, aluminum laurate, aluminum oleate, aluminum behenate, aluminum palmitate, aluminum 2-ethylhexanoate and the like. Carboxylic acid metal salts are used alone or in combination of two or more.

The content of component (E) may be 3% by mass or more, and may be 10% by mass or less, 8% by mass or less, or 6% by mass or less based on the total amount of the composition.

The composition may further contain other ingredients than those mentioned above. Other components include graphite other than expanded graphite, carbon materials such as carbon fiber, metal fibers, glass, inorganic components such as talc, light absorbers that suppress photodegradation, and antioxidants that prevent oxidation. be done. From the viewpoint of further suppressing a decrease in heat storage capacity, the content of other components is preferably 10% by mass or less based on the total amount of the composition.

When an acrylic resin is used as the component (A), the composition may further contain a curing agent from the viewpoint of suppressing liquid leakage and volatilization of the heat storage material and improving heat resistance. The curing agent is a curing agent that can react with the reactive groups contained in the second monomer (acrylic resin). Examples of curing agents include isocyanate curing agents, phenol curing agents, amine curing agents, imidazole curing agents, acid anhydride curing agents, and carboxylic acid curing agents. These curing agents are used singly or in combination of two or more. The content of the curing agent may be 0.01% by mass or more, and may be 10% by mass or less, 5% by mass or less, or 1% by mass or less based on the total amount of the composition.

A sheet-shaped member can be produced using the composition described above. That is, another embodiment of the present invention is a sheet provided with a heat storage layer containing the composition described above.

FIG. 1 is a schematic cross-sectional view showing a sheet according to one embodiment. Sheet 1 comprises, in one embodiment, a heat storage layer containing a heat storage component and expanded graphite. The sheet 1 may be a sheet consisting only of a heat storage layer, and may be, for example, a sheet in which a heat storage layer and a metal layer made of a metal such as aluminum or copper are laminated.

The thickness of the heat storage layer may be, for example, 1 mm or more, 2 mm or more, or 5 mm or more, and may be 30 mm or less, 20 mm or less, or 10 mm or less. When the sheet 1 comprises a metal layer, the thickness of the metal layer may be, for example, 10 μm or more and 100 μm or less.

Sheet 1 is obtained, for example, by the following method. That is, a heat storage component (component (A)), expanded graphite (component (B)), and optionally other components are mixed to obtain a mixture. After that, the sheet 1 can be obtained by pressing the mixture while heating and pressurizing it with a pressure heating press or the like.

Since the heat storage layer is formed from the composition described above, it has high thermal conductivity. The thermal conductivity of the heat storage layer may preferably be 0.5 W/mK or higher, 0.6 W/mK or higher, 0.65 W/mK or higher, 0.8 W/mK or higher, or 0.9 W/mK or higher. . The thermal conductivity of the heat storage layer is measured by measuring the sheet 1 using a thermal conductivity meter (for example, "QTM-500" manufactured by Kyoto Electronics Industry Co., Ltd.).

The heat storage layer has a high heat storage capacity (heat of fusion). The heat of fusion of the heat storage layer may preferably be 90 J/g or more, 95 J/g or more, or 100 J/g or more. The heat of fusion of the heat storage layer is the melting (endothermic) of a thermogram obtained by heating at a temperature elevation rate of 10° C./min using a differential scanning calorimeter (for example, “8500” manufactured by PerkinElmer Co., Ltd.). Calculated from peak areas.

Since the composition and the sheet 1 using the same can store heat or release heat using phase transition, they are suitably used as a heat storage material. That is, another embodiment of the present invention is a heat storage material comprising the composition described above.

The heat storage material (composition, sheet) of this embodiment can be utilized in various fields. Heat storage materials are used, for example, in automobiles, buildings, public facilities, air conditioning equipment in underground malls (improving the efficiency of air conditioning equipment), piping in factories (heat storage in piping), automobile engines (heat insulation around the engine), electronic parts (Prevention of temperature rise of electronic parts), fibers of underwear (maintaining appropriate temperature), etc. This heat storage material does not bleed out due to an increase in the fluidity of the heat storage component even if it exceeds the melting point of the heat storage component, and can suppress the flow of the heat storage material itself. or can be attached in various ways.

In each of these applications, the heat storage material can store the heat of the heat source by being placed in thermal contact with the heat source that generates heat in each application. That is, one embodiment of the present invention is an article comprising a heat source and a heat storage material (the composition described above) provided in thermal contact with the heat source.

FIG. 2 is a schematic cross-sectional view showing one embodiment of an article provided with a heat storage material. As shown in FIG. 2 , the article 2 includes a heat source 3 and a heat storage material 4 provided in thermal contact with the heat source 3 . The heat storage material 4 may be arranged so as to be in thermal contact with at least a portion of the heat source 3. As shown in FIG. You may arrange|position so that the whole may be covered. As long as the heat storage material 4 is in thermal contact with the heat source 3, the heat source 3 and the heat storage material 4 may be in direct contact. member) may be arranged.

For example, when the heat storage material 4 is used with an air conditioner (or parts thereof), piping, or an automobile engine as the heat source 3, the heat source 3 is The heat generated from 3 is stored in the heat storage material 4, and the temperature of the heat source 3 can be easily kept above a certain level (warmed). When the heat storage material 4 is used as the fiber of underwear, the heat storage material 4 stores the heat generated from the human body as the heat source 3, so that the warmth can be felt for a long time.

For example, when the heat storage material 4 is used together with an electronic component as the heat source 3, heat generated by the electronic component can be stored by being placed in thermal contact with the electronic component. In this case, for example, if the heat storage material is placed in further thermal contact with the heat radiating member, the heat stored in the heat storage material can be gradually released, and the heat generated in the electronic component can be rapidly released to the outside. It is possible to suppress the release (the vicinity of the electronic component becomes locally hot). Article 2 may be formed by placing a sheet as described above on heat source 3 .

In another embodiment, the composition described above can be used for applications other than heat storage materials. The composition is suitably used for forming, for example, a water repellent material, an anti-frost material, a refractive index adjusting material, a lubricant, an adsorbent, a thermosetting stress relieving material, or a low dielectric material. The water repellent material, anti-frost material, refractive index modifier, lubricant, adsorbent, thermosetting stress relieving material and low dielectric material may each comprise, for example, the compositions described above.

EXAMPLES The present invention will be specifically described based on Examples, but the present invention is not limited to these Examples.

In Examples and Comparative Examples, compositions having the compositions shown in Tables 1 to 4 were prepared using the components shown below.

In an example using a saturated hydrocarbon or an organic acid ester as a heat storage component, a copolymer of ethylene and an olefin having 3 or more carbon atoms is added and mixed as necessary while the heat storage component is heated to the melting point or higher. bottom. Predetermined amounts of expanded graphite and other components were added thereto and kneaded with a twin-screw kneader (the kneading temperature was adjusted to the melting point or higher of the materials used) to obtain a composition. The obtained composition was pressed by a pressure heating press (pressing temperature: adjusted to the melting point of each material or higher, pressurizing pressure: 1 MPa) to prepare a sheet of 170 mm x 60 mm x 1 mm.

In the example using an acrylic resin as a heat storage component, an acrylic resin was synthesized by a known suspension polymerization method using predetermined amounts of the monomers shown below. The acrylic resin, expanded graphite and other components are mixed and kneaded by a pressure heating press (upper plate 80 ° C./lower plate 40 ° C., pressure 140 kPa), and further pressure heating press (upper and lower hot plates 80 ° C., heating A sheet of 170 mm x 60 mm x 1 mm was produced by pressing with a pressure of 1 MPa).

(Heat storage component)
A-1: Paraffin wax (manufactured by Nippon Seiro Co., Ltd., product name “HNP-9”, melting point 76 ° C.)
A-2: n-hexadecane (manufactured by Tokyo Chemical Industry Co., Ltd., melting point 18 ° C.)
A-3: Methyl stearate (manufactured by Tokyo Chemical Industry Co., Ltd., melting point 40 ° C.)
A-4: Copolymer of stearyl acrylate/butyl acrylate/glycidyl methacrylate = 80/15/5 (mass ratio) (weight average molecular weight: 600,000)
(expanded graphite)
B-1: Expanded graphite pulverized powder (manufactured by Dainen Sangyo Co., Ltd., average particle size 175 to 250 μm)
B-2: Expanded graphite (manufactured by Ito Graphite Industry Co., Ltd., "EC100", average particle size 170 to 230 μm)
B-3: Expanded graphite (Ito Graphite Industry Co., Ltd., product name “EC10”, average particle size 150 to 250 μm)
(Copolymer of ethylene and olefin having 3 or more carbon atoms)
C-1: Copolymer of ethylene and propylene (manufactured by Sumitomo Chemical Co., Ltd., product name “Esprene SPO V0141”)
C-2: Copolymer of ethylene and octene (manufactured by Dow Chemical Japan Co., Ltd., product name “ENGAGE8150”)
C-3: Copolymer of ethylene and octene (manufactured by Dow Chemical Japan Co., Ltd., product name “ENGAGE8003”)
(polypropylene)
D-1: Polypropylene (manufactured by Sumitomo Chemical Co., Ltd., product name “Noblen AU891E2”)
D-2: Polypropylene (manufactured by Sumitomo Chemical Co., Ltd., product name “Noblen W101”)
(Graphite for comparison)
b-1: flaky graphite (manufactured by Ito Graphite Industry Co., Ltd., product name “W-32”, particle size +32 mesh 75% or more)
b-2: Artificial graphite (manufactured by Ito Graphite Industry Co., Ltd., product name “AGB-Special 20”, particle size 60 to 20 mesh, 70% or more)
b-3: Artificial graphite (manufactured by Ito Graphite Industry Co., Ltd., product name “AGB-055, particle size 0.5 to 5 mm, 85% or more)
b-4: Fine graphite powder (manufactured by Showa Denko Co., Ltd., fine powder diameter 7 μm or less (passed through a filter))

(Measurement of thermal conductivity)
Using QTM-500 (manufactured by Kyoto Electronics Industry Co., Ltd.) and PD-11N as a probe, the in-plane thermal conductivity of the sheet was measured.

(Measurement of melting point and heat of fusion)
Using DSC-8500 (manufactured by PerkinElmer Co., Ltd.), the melting point was obtained from the melting peak temperature in the heating process of 10° C./min, and the heat storage capacity (heat of fusion) was calculated from the area. Using a sheet containing neither expanded graphite nor comparative graphite as a control, the ratio of the heat storage capacity of each example and comparative example was determined when the heat storage capacity of the control sheet was taken as 100%, and the decrease in heat storage capacity. rate.

(Evaluation of bleeding)
In the vicinity of the melting point of each resin member, the presence or absence of liquid exudation was determined visually and by touch.

DESCRIPTION OF SYMBOLS 1... Sheet, 2... Article, 3... Heat source, 4... Heat storage material.

Claims (11)

A composition containing a heat storage component and expanded graphite,
The content of the expanded graphite is 20% by mass or more based on the total amount of the composition,
A composition in which the heat storage component is a saturated hydrocarbon, an organic acid ester, or an acrylic resin (however, a composition containing a hydrogenated conjugated diene copolymer, and a conjugated diene-based (co)polymer and a fatty acid (excluding compositions containing at least one selected from metal salts). 2. The composition of claim 1, wherein said heat storage component is said saturated hydrocarbon. 2. The composition according to claim 1, wherein said heat storage component is said organic acid ester. 2. The composition according to claim 1, wherein said heat storage component is said acrylic resin. The composition according to any one of claims 1 to 4, further comprising a copolymer of ethylene and an olefin having 3 or more carbon atoms. The composition according to claim 5, wherein said olefin has 3 to 8 carbon atoms. The composition according to claim 5 or 6, further comprising at least one polyolefin selected from the group consisting of polyethylene and polypropylene. A sheet comprising a heat storage layer containing the composition according to any one of claims 1 to 7. 9. The sheet according to claim 8, wherein the heat storage layer has a thermal conductivity of 0.5 W/mK or higher. A heat storage material comprising the composition according to any one of claims 1 to 7. a heat source;
and a composition according to any one of claims 1 to 7, provided in thermal contact with said heat source.

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