WO2021241167A1

WO2021241167A1 - Heat storage body and method for manufacturing heat storage body

Info

Publication number: WO2021241167A1
Application number: PCT/JP2021/017520
Authority: WO
Inventors: 哲朗三ツ井; 優樹中川
Original assignee: 富士フイルム株式会社
Priority date: 2020-05-25
Filing date: 2021-05-07
Publication date: 2021-12-02
Also published as: TW202202597A

Abstract

The present invention provides a heat storage body in which the occurrence of defects during handling is suppressed, and a method for manufacturing the heat storage body. The heat storage body of the present invention includes a microcapsule in which a heat storage material is enclosed and a resin, wherein the content of the heat storage material with respect to the total mass of the heat storage body is 65% by mass or more, and the void ratio is less than 10% by volume.

Description

Heat storage body, manufacturing method of heat storage body

The present invention relates to a heat storage body and a method for manufacturing the heat storage body.

In recent years, microcapsules containing functional materials such as heat storage materials, fragrances, dyes, and pharmaceutical ingredients have attracted attention.
For example, Patent Document 1 discloses a heat storage sheet-shaped molded body obtained by molding and curing a heat storage acrylic resin composition containing a predetermined amount of microcapsules containing a heat storage material into a sheet shape.

Japanese Unexamined Patent Publication No. 2007-031610

On the other hand, in recent years, it has been desired to increase the amount of microcapsules containing a heat storage material in order to improve the heat storage property. That is, it is desired to increase the content of the microcapsules (particularly, the heat storage material) in the heat storage body.

The present inventors increased the amount of microcapsules containing a heat storage material as described in Patent Document 1, and when handling the obtained heat storage material (particularly when the heat storage material was pulled). , It was found that defects (for example, cracks and cracks) are likely to occur in the heat storage body. In particular, when the heat storage body is thick, defects are likely to occur in the heat storage body.

In view of the above circumstances, it is an object of the present invention to provide a heat storage body in which the occurrence of defects during handling is suppressed.
Another object of the present invention is to provide a method for producing a heat storage body.

As a result of diligent studies on the above problems, the present inventors have found that the above problems can be solved by the following configuration.

(1) A heat storage body containing a microcapsule containing a heat storage material and a resin.
The content of the heat storage material with respect to the total mass of the heat storage body is 65% by mass or more.
A heat storage body having a porosity of less than 10% by volume.
(2) The heat storage body according to (1), wherein the content of the resin is 20% by mass or less with respect to the total mass of the heat storage body.
(3) The heat storage body according to (1) or (2), wherein the elastic modulus of the resin is 15 MPa or less.
(4) The heat storage body according to any one of (1) to (3), wherein the glass transition temperature of the resin is 50 ° C. or lower.
(5) The heat storage body according to any one of (1) to (4), wherein the elongation at break of the resin is 300% or more.
(6) The heat storage body according to any one of (1) to (5), wherein the ratio of the thickness of the capsule wall of the microcapsule to the volume-based median diameter of the microcapsule is 0.0075 or less.
(7) The heat storage body according to any one of (1) to (6), wherein the thickness of the capsule wall of the microcapsule is 0.20 μm or less.
(8) The heat storage body according to any one of (1) to (7), wherein the deformation rate of the microcapsules is 35% or more.
(9) The heat storage body according to any one of (1) to (8), wherein the capsule wall of the microcapsule and the resin have the same functional group.
(10) The heat storage material according to any one of (1) to (9), wherein the resin contains at least one selected from the group consisting of polyurethane, polyurea, and polyurethane urea.
(11) The method according to any one of (1) to (10), wherein both the resin and the capsule wall of the microcapsules contain at least one selected from the group consisting of polyurethane, polyurea, and polyurethane urea. Heat storage body.
(12) The heat storage body according to any one of (1) to (11), wherein the porosity is 5% by volume or less.
(13) The heat storage body according to any one of (1) to (12), which has a thickness of 0.5 mm or more.
(14) The method for producing a heat storage body according to any one of (1) to (13).
A method for producing a heat storage body, which comprises producing a heat storage body using a composition for forming a heat storage body containing microcapsules, a resin, and water.
(15) The method for producing a heat storage body according to (14), wherein the resin in the composition for forming a heat storage body is in the form of particles.

According to the present invention, it is possible to provide a heat storage body in which the occurrence of defects during handling is suppressed.
Further, according to the present invention, it is also possible to provide a method for producing a heat storage body.

Hereinafter, the present invention will be described in detail.
In the present specification, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stepwise description. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.

The various components described later may be used alone or in combination of two or more. For example, the polyisocyanate described later may be used alone or in combination of two or more.

The heat storage body of the present invention contains a predetermined amount of heat storage material and has a porosity of less than 10% by volume.
According to the heat storage body of the present invention, the occurrence of defects during handling can be suppressed. This is presumed to be due to the following reasons.
As the amount of microcapsules containing the heat storage material increases, defects are likely to occur in the heat storage material. It is considered that by lowering the porosity of such a heat storage material, the contact area between the microcapsules in the heat storage body is widened, and the strength of the heat storage body is improved. As a result, it is presumed that the brittleness of the heat storage body is increased and the occurrence of defects (for example, cracks and cracks) during handling of the heat storage body can be suppressed.

The heat storage material of the present invention contains microcapsules containing the heat storage material and a resin, and the content ratio of the heat storage material to the total mass of the heat storage material is 65% by mass or more, and the void ratio is less than 10% by volume.
Hereinafter, the materials contained in the heat storage body will be described in detail first, and then the characteristics of the heat storage body will be described in detail.

<Microcapsules>
The microcapsule has a core portion and a capsule wall for encapsulating a core material (encapsulated material (also referred to as an encapsulating component)) forming the core portion.

The microcapsule contains a heat storage material as a core material (inclusion component). Since the heat storage material is encapsulated in microcapsules, the heat storage material can stably exist in a phase state depending on the temperature.

(Heat storage material)
The type of heat storage material is not particularly limited, and a material that changes phase in response to a temperature change can be used, and the phase change between the solid phase and the liquid phase that accompanies the state change of melting and solidification in response to the temperature change is repeated. Materials that can be used are preferred.
The phase change of the heat storage material is preferably based on the phase change temperature of the heat storage material itself, and in the case of the phase change between the solid phase and the liquid phase, it is preferably based on the melting point.

As the heat storage material, for example, a material that can store heat generated outside the heat storage body as sensible heat and a material that can store heat generated outside the heat storage body as latent heat (hereinafter, also referred to as "latent heat storage material". ), A material that causes a phase change due to a reversible chemical change, or the like. The heat storage material is preferably one that can release the stored heat.
Among them, the latent heat storage material is preferable as the heat storage material in terms of ease of control of the amount of heat that can be transferred and received and the size of the amount of heat.

The latent heat storage material is a material that stores heat generated outside the heat storage body as latent heat. For example, in the case of a phase change between a solid phase and a liquid phase, it refers to a material capable of transferring heat by latent heat by repeating a change between melting and solidification with the melting point determined by the material as the phase change temperature.
In the case of a phase change between a solid phase and a liquid phase, the latent heat storage material utilizes the heat of fusion at the melting point and the heat of solidification at the freezing point, and can store heat and dissipate heat with the phase change between the solid and the liquid.

The type of the latent heat storage material is not particularly limited, and can be selected from compounds having a melting point and capable of a phase change.
Examples of the latent heat storage material include ice (water); inorganic salts; aliphatic hydrocarbons such as paraffin (for example, isoparaffin and normal paraffin); tri (capryl capric acid) glyceryl, methyl myristate (melting point 16-19 ° C.). ), Fatty acid ester compounds such as isopropyl myristate (melting point 167 ° C.) and dibutyl phthalate (melting point −35 ° C.); alkylnaphthalene compounds such as diisopropylnaphthalene (melting point 67-70 ° C.), 1-phenyl-1. -Diarylalkane compounds such as xylylethane (melting point less than -50 ° C), alkylbiphenyl compounds such as 4-isopropylbiphenyl (melting point 11 ° C), triarylmethane compounds, alkylbenzene compounds, benzylnaphthalene compounds, diarylalkylene compounds. Aromatic hydrocarbons such as compounds and arylindan compounds; natural animal and vegetable oils such as camellia oil, soybean oil, corn oil, cottonseed oil, rapeseed oil, olive oil, palm oil, castor oil, and fish oil; mineral oil; diethyl ethers. ; Fat group diols; sugars; sugar alcohols and the like.

The phase change temperature of the heat storage material is not particularly limited, and may be appropriately selected depending on the type of the heating element that generates heat, the heating element temperature of the heating element, the temperature or holding temperature after cooling, the cooling method, and the like.
As the heat storage material, it is preferable to select a material having a phase change temperature (preferably melting point) in a target temperature range (for example, the operating temperature of the heating element; hereinafter also referred to as “heat control region”).
The phase change temperature of the heat storage material varies depending on the heat control region, but is preferably 0 to 80 ° C, more preferably 10 to 70 ° C.

When applied to an electronic device (particularly, a small-sized or portable electronic device), the heat storage material having the following melting points is preferable.
(1) As the heat storage material (preferably a latent heat storage material), a heat storage material having a melting point of 0 to 80 ° C. is preferable.
When a heat storage material having a melting point of 0 to 80 ° C. is used, the material having a melting point of less than 0 ° C. or more than 80 ° C. is not included in the heat storage material. Among the materials having a melting point of less than 0 ° C. or more than 80 ° C., the material in a liquid state may be used in combination with the heat storage material as a solvent.
(2) Among the above (1), a heat storage material having a melting point of 10 to 70 ° C. is preferable.
When a heat storage material having a melting point of 10 to 70 ° C. is used, the material having a melting point of less than 10 ° C. or more than 70 ° C. is not included in the heat storage material. Among the materials having a melting point of less than 10 ° C. or more than 70 ° C., the material in a liquid state may be used in combination with the heat storage material as a solvent.
(3) Further, in the above (2), a heat storage material having a melting point of 15 to 50 ° C. is preferable.
When a heat storage material having a melting point of 15 to 50 ° C. is used, the material having a melting point of less than 15 ° C. or more than 50 ° C. is not included in the heat storage material. Among the materials having a melting point of less than 15 ° C. or more than 50 ° C., the material in a liquid state may be used in combination with the heat storage material as a solvent.
(4) Further, in the above (2), a heat storage material having a melting point of 20 to 62 ° C. is also preferable.
In particular, heating elements of thin or portable electronic devices such as notebook computers, tablets, and smartphones often have an operating temperature of 20 to 65 ° C, and it is suitable to use a heat storage material having a melting point of 20 to 62 ° C. ing. When a heat storage material having a melting point of 20 to 62 ° C. is used, the material having a melting point of less than 20 ° C. or more than 62 ° C. is not included in the heat storage material. Of the materials having a melting point of less than 20 ° C or higher than 62 ° C, the material in a liquid state may be used in combination with a heat storage material as a solvent, but the fact that the material does not contain a solvent produces a large amount of heat generated by the heating element. It is preferable in that it absorbs heat.

Among them, an aliphatic hydrocarbon is preferable as the latent heat storage material, and paraffin is more preferable, in that the heat storage property of the heat storage body is more excellent and the void ratio of the microcapsules can be reduced.
The melting point of the aliphatic hydrocarbon (preferably paraffin) is not particularly limited, but is preferably 0 ° C. or higher, more preferably 15 ° C. or higher, still more preferably 20 ° C. or higher in terms of application of the heat storage member to various uses. The upper limit is not particularly limited, but is preferably 80 ° C. or lower, more preferably 70 ° C. or lower, further preferably 60 ° C. or lower, and particularly preferably 50 ° C. or lower.
As the aliphatic hydrocarbon, a linear aliphatic hydrocarbon is preferable in that the heat storage property of the heat storage member is more excellent. The number of carbon atoms of the linear aliphatic hydrocarbon is not particularly limited, but 14 or more is preferable, 16 or more is more preferable, and 17 or more is further preferable. The upper limit is not particularly limited, but is preferably 26 or less.
As the aliphatic hydrocarbon, a linear aliphatic hydrocarbon having a melting point of 0 ° C. or higher is preferable, and a linear aliphatic hydrocarbon having a melting point of 0 ° C. or higher and having 14 or more carbon atoms is more preferable. preferable.

Examples of the linear aliphatic hydrocarbon (melting point paraffin) having a melting point of 0 ° C. or higher include n-tetradecane (melting point 6 ° C.), n-pentadecane (melting point 10 ° C.), and n-hexadecane (melting point 18 ° C.). ℃), n-heptadecan (melting point 22 ℃), n-octadecane (melting point 28 ℃), n-nonadecan (melting point 32 ℃), n-eicosan (melting point 37 ℃), n-henikosan (melting point 40 ℃), n- Docosan (melting point 44 ° C), n-tricosan (melting point 48-50 ° C), n-tetracosan (melting point 52 ° C), n-pentacosan (melting point 53-56 ° C), n-hexakosan (melting point 57 ° C), n-heptacosan (Melting point 60 ° C.), n-octacosane (melting point 62 ° C.), n-nonakosan (melting point 63-66 ° C.), and n-triacontane (melting point 66 ° C.).
Among them, n-heptadecan (melting point 22 ° C.), n-octadecane (melting point 28 ° C.), n-nonadecan (melting point 32 ° C.), n-eicosan (melting point 37 ° C.), n-henikosan (melting point 40 ° C.), n- Docosan (melting point 44 ° C), n-tricosan (melting point 48-50 ° C), n-tetracosan (melting point 52 ° C), n-pentacosan (melting point 53-56 ° C), n-hexakosan (melting point 60 ° C), n-heptacosan (Melting point 60 ° C.) or n-octacosane (melting point 62 ° C.) is preferable.

When a linear aliphatic hydrocarbon is used as the heat storage material, the content of the linear aliphatic hydrocarbon is preferably 80% by mass or more, preferably 90% by mass or more, based on the content of the heat storage material. Is more preferable, 95% by mass or more is further preferable, and 98% by mass or more is particularly preferable. The upper limit is 100% by mass.

As the inorganic salt, an inorganic hydrate is preferable, and for example, an alkali metal chloride hydrate (eg, sodium chloride dihydrate, etc.) and an alkali metal acetate hydrate (eg, sodium acetate water) are preferable. Japanese products, etc.), alkali metal sulfate hydrate (eg, sodium sulfate hydrate, etc.), alkali metal thiosulfate hydrate (eg, thiosulfate sodium hydrate, etc.), alkaline earth metal Examples thereof include sulfate hydrate (eg, calcium sulfate hydrate, etc.) and alkaline earth metal chloride hydrate (eg, calcium chloride hydrate, etc.).
Examples of the aliphatic diol include 1,6-hexanediol and 1,8-octanediol.
Examples of sugars and sugar alcohols include xylitol, erythritol, galactitol, and dihydroxyacetone.

As the heat storage material, one type may be used alone, or two or more types may be mixed and used. By using one type of heat storage material alone or by using a plurality of types having different melting points, the temperature range in which heat storage property is exhibited and the amount of heat storage can be adjusted according to the application.
The temperature range in which heat can be stored can be expanded by mixing the heat storage material having a melting point before and after the heat storage material having a melting point at the center temperature at which the heat storage effect of the heat storage material is desired to be obtained. To specifically explain the case of using paraffin as the heat storage material as an example, paraffin a having a melting point at the center temperature at which the heat storage effect of the heat storage material is desired is used as the core material, and the number of carbon atoms before and after the paraffin a and the paraffin a is set. By mixing with other paraffins that have, the heat storage body can be designed to have a wide temperature region (heat control region).
The content of paraffin having a melting point at the center temperature at which the heat storage action is desired is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, and 95% by mass or more with respect to the total mass of the heat storage material. Is more preferable, and 98% by mass or more is particularly preferable. The upper limit is 100% by mass.

When paraffin is used as the heat storage material, one type of paraffin may be used alone, or two or more types may be mixed and used. When a plurality of types of paraffin having different melting points are used, the temperature range in which heat storage property is exhibited can be widened. When a plurality of paraffins having different melting points are used, a mixture containing only linear paraffins without substantially containing branched chain paraffins is desirable in order not to reduce the endothermic property. Here, substantially free of branched-chain paraffin means that the content of branched-chain paraffin is 5% by mass or less with respect to the total mass of paraffin, and 2% by mass or less. Is preferable, and 1% by mass or less is more preferable.
On the other hand, as the heat storage material for application to electronic devices, it is also preferable that there is substantially one type of paraffin. When there is substantially one type, paraffin is filled in the heat storage body with high purity, so that the heat absorption property of the electronic device with respect to the heating element is good. Here, substantially one type of paraffin means that the content of the main paraffin is 95 to 100% by mass with respect to the total mass of paraffin, and is preferably 98 to 100% by mass.

When a plurality of paraffins are used, the content of the main paraffin is not particularly limited in terms of the temperature range in which heat storage is exhibited and the amount of heat storage, but 80 to 100% by mass is preferable with respect to the total mass of paraffin. 90 to 100% by mass is more preferable, and 95 to 100% by mass is further preferable.
The "main paraffin" refers to the paraffin having the highest content among the plurality of paraffins contained. The content of the main paraffin is preferably 50% by mass or more with respect to the total mass of paraffin.
The content of paraffin is not particularly limited, but is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and 95 to 100% by mass with respect to the total mass of the heat storage material (preferably latent heat storage material). More preferably, 98 to 100% by mass is particularly preferable.
Further, the paraffin is preferably linear paraffin, and preferably does not substantially contain branched chain paraffin. This is because the heat storage property is further improved by containing the linear paraffin and substantially not containing the branched paraffin. It is presumed that the reason for this is that the association between the molecules of linear paraffin can be suppressed from being inhibited by the branched-chain paraffin.

The content of the heat storage material in the heat storage body is 65% by mass or more with respect to the total mass of the heat storage body.
Among them, 70% by mass or more is preferable, and 75% by mass or more is more preferable, because the effect of the present invention is more excellent. The upper limit of the content of the heat storage material is not particularly limited, but in terms of the strength of the heat storage body, it is preferably 99.9% by mass or less, more preferably 99% by mass or less, and 98% by mass or less with respect to the total mass of the heat storage body. Is more preferable.

(Other ingredients)
The core material of the microcapsules may contain components other than the above-mentioned heat storage material. Other components that can be encapsulated in the microcapsules as the core material include, for example, a solvent and an additive such as a flame retardant.
The content of the heat storage material in the core material is not particularly limited, but 80 to 100% by mass is preferable, and 90 to 100% by mass is more preferable with respect to the total mass of the core material in that the heat storage property of the heat storage body is more excellent. ..

The microcapsules may contain a solvent as a core material.
Examples of the solvent in this case include the above-mentioned heat storage material whose melting point is outside the temperature range in which the heat storage body is used (heat control range; for example, the operating temperature of the heat storage body). That is, the solvent refers to a solvent that does not undergo a phase change in the liquid state in the heat control region, and is distinguished from a heat storage material that causes a phase transition in the heat control region and causes an endothermic reaction.

The content of the solvent in the core material is not particularly limited, but is preferably less than 30% by mass, more preferably less than 10% by mass, still more preferably 1% by mass or less, based on the total mass of the core material. The lower limit is not particularly limited, but may be 0% by mass.

Examples of other components that can be included in the microcapsules as the core material include additives such as ultraviolet absorbers, light stabilizers, antioxidants, waxes, and odor suppressants.

(Capsule wall (wall))
The microcapsules have a capsule wall that encloses the core material.
The material for forming the capsule wall in the microcapsules is not particularly limited, and examples thereof include polymers, and specific examples thereof include polyurethane urea, polyurethane, polyurea, melamine resin, and acrylic resin.
The capsule wall preferably contains polyurethane, polyurea, polyurethane urea, or melamine resin, and more preferably contains polyurethane, polyurea, or polyurethane urea, in that the capsule wall can be made thinner and the heat storage property of the heat storage body is more excellent. preferable.
The polyurethane is a polymer having a plurality of urethane bonds, and a reaction product of a polyol and a polyisocyanate is preferable.
Further, the polyurea is a polymer having a plurality of urea bonds, and a reaction product of a polyamine and a polyisocyanate is preferable.
Further, the polyurethane urea is a polymer having a urethane bond and a urea bond, and a reaction product of a polyol, a polyamine, and a polyisocyanate is preferable. When the polyol and the polyisocyanate are reacted, a part of the polyisocyanate reacts with water to form a polyamine, and as a result, polyurethane urea may be obtained.

The capsule wall of the microcapsules preferably has a urethane bond. Capsule walls with urethane bonds are obtained, for example, using the polyurethane ureas or polyurethanes described above.
Since the urethane bond is a highly motile bond, it can provide thermoplasticity to the capsule wall. In addition, it is easy to adjust the flexibility of the capsule wall. Therefore, for example, if the drying time during the production of the heat storage body is lengthened, the microcapsules are easily deformed and bonded to each other. As a result, the microcapsules can easily form a close-packed structure, so that the porosity of the heat storage body can be further reduced.

Further, it is preferable that the microcapsules exist as deformable particles.
When the microcapsules are deformable particles, the microcapsules can be deformed without breaking, and the filling rate of the microcapsules in the heat storage body can be improved. As a result, it becomes possible to increase the amount of the heat storage material in the heat storage body, and it is possible to realize more excellent heat storage property.
The fact that the microcapsules are deformed without breaking means that the microcapsules are deformed from the shape in a state where no external pressure is applied to each microcapsule, regardless of the degree of deformation. Deformations that occur in microcapsules include deformations in which when microcapsules are pressed against each other in a heat storage body, spherical surfaces come into contact with each other to form a planar surface, or a contact surface in which one is convex and the other is concave. Is done.
Polyurethane urea, polyurethane, or polyurea is preferable, polyurethane urea or polyurethane is more preferable, and polyurethane urea is further preferable as the material for forming the capsule wall in that the microcapsules can be deformable particles.

As described above, polyurethane, polyurea, and polyurethane urea are preferably formed using polyisocyanate.

The polyisocyanate is a compound having two or more isocyanate groups, and examples thereof include aromatic polyisocyanates and aliphatic polyisocyanates.
Examples of the aromatic polyisocyanate include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, naphthalene-1,4-diisocyanate, and diphenylmethane-4,4'-. Diisocyanate, 3,3'-dimethoxy-biphenyldiisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, 4-chloroxylylene-1 , 3-Diisocyanate, 2-methylxylylene-1,3-diisocyanate, 4,4'-diphenylpropanediisocyanate, and 4,4'-diphenylhexafluoropropanediisocyanate.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, and cyclohexylene-1,3-diisocyanate. , Cyclohexylene-1,4-diisocyanate, dicyclohexammethane-4,4'-diisocyanate, 1,4-bis (isocyanatemethyl) cyclohexane, 1,3-bis (isocyanatemethyl) cyclohexane, isophorone diisocyanate, lysine diisocyanate, and Hexamethylene diisocyanate can be mentioned.

Although bifunctional aromatic polyisocyanates and aliphatic polyisocyanates have been exemplified above, trifunctional or higher functional polyisocyanates (for example, trifunctional triisocyanates and tetrafunctional tetraisocyanates) may also be used as polyisocyanates. Can be mentioned.
More specifically, the polyisocyanate includes a burette or isocyanurate which is a trimer of the above-mentioned bifunctional polyisocyanate, an adduct of a polyol such as trimethylolpropane and a bifunctional polyisocyanate, and benzene. Examples thereof include formarin condensates of isocyanates, polyisocyanates having a polymerizable group such as methacryloyloxyethyl isocyanate, and lysine triisocyanates.
Polyisocyanates are described in the "Polyurethane Resin Handbook" (edited by Keiji Iwata, published by Nikkan Kogyo Shimbun (1987)).

Among them, as the polyisocyanate, a trifunctional or higher functional polyisocyanate is preferable.
Examples of the trifunctional or higher functional polyisocyanate include a trifunctional or higher functional aromatic polyisocyanate and a trifunctional or higher functional aliphatic polyisocyanate.
As the trifunctional or higher functional polyisocyanate, an adduct form (addition) of a bifunctional polyisocyanate and a compound having three or more active hydrogen groups in the molecule (for example, a trifunctional or higher functional polyol, polyamine, polythiol, etc.) A trifunctional or higher polyisocyanate (adduct type trifunctional or higher polyisocyanate) and a trimer of bifunctional polyisocyanate (biuret type or isocyanurate type) are also preferable.

Examples of the adduct-type trifunctional or higher-functional polyisocyanate include Takenate® D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, and D-. 140N, D-160N (all manufactured by Mitsui Chemicals, Inc.), Death Module (registered trademark) L75, UL57SP (manufactured by Sumika Bayer Urethane Co., Ltd.), Coronate (registered trademark) HL, HX, L (manufactured by Nippon Polyurethane Co., Ltd.) ), P301-75E (manufactured by Asahi Kasei Corporation), and Barnock (registered trademark) D-750 (manufactured by DIC Co., Ltd.).
Among them, as the adduct-type trifunctional or higher polyisocyanate, Takenate (registered trademark) D-110N, D-120N, D-140N, D-160N manufactured by Mitsui Chemicals, Inc., or Barnock manufactured by DIC Corporation. (Registered trademark) D-750 is preferable.
Examples of the isocyanurate-type trifunctional or higher functional isocyanate include Takenate (registered trademark) D-127N, D-170N, D-170HN, D-172N, D-177N, and D-204 (manufactured by Mitsui Chemicals, Inc.). , Sumijour N3300, Death Module (registered trademark) N3600, N3900, Z4470BA (Sumika Bayer Urethane), Coronate (registered trademark) HX, HK (manufactured by Nippon Polyurethane Industry Co., Ltd.), Duranate (registered trademark) TPA-100, TKA- 100, TSA-100, TSS-100, TLA-100, TSE-100 (manufactured by Asahi Kasei Corporation) can be mentioned.
Biuret-type trifunctional or higher functional isocyanates include, for example, Takenate (registered trademark) D-165N, NP1100 (manufactured by Mitsui Chemicals, Inc.), Death Module (registered trademark) N3200 (Sumitomo Bayer Urethane), and Duranate (registered trademark). ) 24A-100 (manufactured by Asahi Kasei Corporation).

The polyol is a compound having two or more hydroxyl groups, and is, for example, a low molecular weight polyol (eg, aliphatic polyol, aromatic polyol), a polyether polyol, a polyester-based polyol, a polylactone-based polyol, a castor oil-based polyol. , Polyol-based polyols, and hydroxyl group-containing amine-based compounds.
The low molecular weight polyol means a polyol having a molecular weight of 300 or less, for example, bifunctional low molecular weight polyols such as ethylene glycol, diethylene glycol, and propylene glycol, as well as glycerin, trimethylolpropane, hexanetriol, and penta. Examples thereof include trifunctional or higher low molecular weight polyols such as erythritol and sorbitol.
As the above-mentioned polyol, a small molecule polyol is preferable because the microcapsules are easily deformed.

Examples of the hydroxyl group-containing amine compound include amino alcohols as oxyalkylated derivatives of amino compounds. Examples of the amino alcohol include N, N, N', N'-tetrakis [2-hydroxypropyl] ethylenediamine, which are propylene oxides or adducts of ethylene oxide of amino compounds such as ethylenediamine, and N, N, N'. , N'-Tetrakis [2-hydroxyethyl] ethylenediamine and the like.

A polyamine is a compound having two or more amino groups (primary amino group or secondary amino group), and is a fat such as diethylenetriamine, triethylenetetramine, 1,3-propylenediamine, and hexamethylenediamine. Group polyvalent amines; Epoxy compound adducts of aliphatic polyvalent amines; Alicyclic polyvalent amines such as piperazine; and 3,9-bis-aminopropyl-2,4,8,10-tetraoxaspiro- ( 5,5) Examples thereof include heterocyclic diamines such as undecane.

The mass of the capsule wall in the microcapsule is not particularly limited, but is preferably 12% by mass or less, more preferably 10% by mass or less, based on the total mass of the heat storage material contained in the core portion. The fact that the mass of the capsule wall is 12% by mass or less with respect to the heat storage material which is the inclusion component indicates that the capsule wall is a thin wall. By making the capsule wall a thin wall, the content of the microcapsules containing the heat storage material in the heat storage body is increased, and as a result, the heat storage property of the heat storage member becomes more excellent.
The lower limit of the mass of the capsule wall is not particularly limited, but 1% by mass or more is preferable, 2% by mass or more is more preferable, and 3% by mass is more preferable with respect to the total mass of the heat storage material in terms of maintaining the pressure resistance of the microcapsules. The above is more preferable.

(Physical characteristics of microcapsules)
-Particle size-
The particle size of the microcapsules is not particularly limited, but the volume-based median diameter (Dm) is preferably 1 to 80 μm, more preferably 10 to 70 μm, and even more preferably 15 to 50 μm. The smaller the particle size of the microcapsules, the smaller the voids between the microcapsules and the wider the contact area between the microcapsules, so that the occurrence of defects during handling can be further suppressed. In that respect, the particle size of the microcapsules is preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less in terms of volume-based median diameter (Dm).
The volume-based median diameter of the microcapsules can be controlled by changing the dispersion conditions in the emulsification step of the method described below for the method of producing microcapsules.
Here, the volume-based median diameter of microcapsules is a grain in which the total volume of particles on the large diameter side and the small diameter side is equal when the entire microcapsule is divided into two with the particle size as a threshold. Refers to the diameter. The volume-based median diameter of the microcapsules is measured by a laser diffraction / scattering method using a Microtrack MT3300EXII (manufactured by Nikkiso Co., Ltd.).
As a method for separating the microcapsules, the isolated microcapsules can be obtained by immersing the heat storage body in water for 24 hours or more and centrifuging the obtained aqueous dispersion.

-Particle size distribution-
The particle size distribution of the microcapsules is not particularly limited, but the CV (Coefficient of Variation) value (correlation coefficient) of the median diameter based on the volume of the microcapsules calculated by the following formula may be 10 to 100%. preferable.
CV value = standard deviation σ / median diameter x 100
The standard deviation σ is calculated based on the volume-based particle size of the microcapsules measured according to the above-mentioned method for measuring the median diameter.

-Wall thickness-
The thickness (wall thickness) of the capsule wall of the microcapsules is not particularly limited, but the thinner the capsule wall, the easier it is to deform, reduce the number of voids, and / or increase the contact area between the microcapsules. Therefore, it is possible to further suppress the occurrence of defects during handling. Specifically, 10 μm or less is preferable, 0.20 μm or less is more preferable, 0.15 μm or less is further preferable, and 0.11 μm or less is particularly preferable, in that the effect of the present invention is more excellent. On the other hand, since the strength of the capsule wall can be maintained by having a certain thickness, the wall thickness is preferably 0.01 μm or more, more preferably 0.05 μm or more.
The wall thickness is an average value obtained by determining the individual wall thickness (μm) of any 20 microcapsules with a scanning electron microscope (SEM) and averaging them.
Specifically, a cross-sectional section of the heat storage body is prepared, the cross section is observed using SEM, and 20 microcapsules are formed for the microcapsules having a size of ± 10% of the median diameter calculated by the above-mentioned measurement method. select. The wall thickness of the microcapsules is determined by observing the cross section of each of the selected microcapsules, measuring the wall thickness, and calculating the average value of the wall thicknesses of the 20 microcapsules.

When the volume-based median diameter of the above-mentioned microcapsules is Dm [unit: μm] and the thickness of the capsule wall of the above-mentioned microcapsules is δ [unit: μm], the microcapsules with respect to the volume-based median diameter of the microcapsules. The ratio of the thickness of the capsule wall (δ / Dm) is preferably 0.02 or less, more preferably 0.0075 or less, further preferably 0.006 or less, and particularly preferably 0.005 or less. When δ / Dm is 0.0075 or less, the microcapsules are easily deformed during the production of the heat storage body, so that the porosity of the heat storage body can be particularly low and / or the adjacency ratio of the microcapsules described later is particularly high. can.
The lower limit of δ / Dm is preferably 0.001 or more, more preferably 0.0015 or more, still more preferably 0.0025 or more, from the viewpoint of maintaining the strength of the microcapsules.

-Deformation rate-
The deformation rate of the microcapsules is not particularly limited, but a larger deformation rate is preferable in that the porosity of the capsule can be reduced and the capsule adjacency ratio can be increased. Here, the deformation rate of the microcapsules means a value measured by the following method.
By directly removing the microcapsules from the heat storage body forming composition or eluting the microcapsules from the heat storage body with a solvent, 15 microcapsules having a particle size within ± 10% of the average value are taken out. The microcapsules are heated on a hot plate set to a temperature of + 5 ° C. at which the inclusion component melts to melt the inclusion component. The maximum distance that the flat indenter sinks by contacting the microcapsules with the contained components in a molten state with a 0.1 mm square flat indenter using an indentation hardness tester and then pressing with a maximum indentation load of 1 mN. Measure the value (maximum indentation depth).
From the above measurement results, the value of (maximum indentation depth (unit: μm)) / (microcapsule median diameter Dm (unit: μm)) × 100 was calculated, and the average value of the measured 15 pieces was calculated. , The deformation rate of the microcapsules. The larger the deformation rate, the larger the deformation of the microcapsules. As the indentation hardness tester, an HM2000 type micro hardness tester manufactured by Fisher Instruments Co., Ltd. can be used.
As the deformation rate of the microcapsules, 30% or more is preferable, 35% or more is more preferable, 40% or more is further preferable, and 50% or more is particularly preferable, because the effect of the present invention is more excellent. In particular, when the deformation rate is 35% or more, the effect is more excellent. The upper limit is not particularly limited, but is, for example, 100% or less, preferably 60% or less from the viewpoint of ease of handling during manufacturing and the like.

The deformation rate of the microcapsules depends on, for example, the thickness of the capsule wall of the microcapsules, the ratio of the thickness of the capsule wall of the microcapsules to the median diameter based on the volume of the microcapsules (δ / Dm), and the material forming the capsule wall. , Can be adjusted.

The content of the microcapsules in the heat storage body is not particularly limited, but 80% by mass or more is preferable, and 85 to 99% by mass is more preferable with respect to the total mass of the heat storage body, in that the heat storage property of the heat storage body is more excellent. 90 to 99% by mass is more preferable.

(Manufacturing method of microcapsules)
The method for producing microcapsules is not particularly limited, and known methods can be adopted.
For example, when the capsule wall contains polyurethane urea, polyurethane, or polyurea, a step of dispersing an oil phase containing a heat storage material and a capsule wall material in an aqueous phase containing an emulsifier to prepare an emulsion (emulsification step). An interface polymerization method including a step of forming a capsule wall by polymerizing a capsule wall material at an interface between an oil phase and an aqueous phase to form a microcapsule containing a heat storage material (encapsulation step) can be mentioned.
When the capsule wall contains melamine resin, the oil phase containing the heat storage material is dispersed in the aqueous phase containing the emulsifier to prepare an emulsified solution (emulsification step), and the capsule wall material is added to the aqueous phase to emulsify. A core selvation method including a step of forming a polymer layer of a capsule wall material on the surface of a droplet to form a microcapsule containing a heat storage material (encapsulation step) can be mentioned.
The capsule wall material means a material that can form a capsule wall.
In the following, each step of the interfacial polymerization method will be described in detail.

In the emulsification step of the interfacial polymerization method, an oil phase containing a heat storage material and a capsule wall material is dispersed in an aqueous phase containing an emulsifier to prepare an emulsion. The capsule wall material contains at least a polyisocyanate and at least one selected compound consisting of a polyol and a polyamine.
The emulsion is formed by dispersing an oil phase containing a heat storage material and a capsule wall material in an aqueous phase containing an emulsifier.
The oil phase contains at least a heat storage material and a capsule wall material, and may further contain other components such as a solvent and / or an additive, if necessary. As the solvent that may be contained in the oil phase, a water-insoluble organic solvent is preferable, and ethyl acetate, methyl ethyl ketone, or toluene is more preferable, because the dispersion stability is excellent.
The aqueous phase can include at least an aqueous medium and an emulsifier.
Examples of the aqueous medium include water and a mixed solvent of water and a water-soluble organic solvent, and water is preferable. "Water-soluble" means that the amount of the target substance dissolved in 100% by mass of water at 25 ° C. is 5% by mass or more.
The content of the aqueous medium is not particularly limited, but is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and 40 to 60% by mass with respect to the total mass of the emulsion which is a mixture of the oil phase and the aqueous phase. % Is more preferable.

Examples of the emulsifier include a dispersant, a surfactant and a combination thereof.
As the dispersant, a known dispersant can be used, and polyvinyl alcohol is preferable.
Examples of the surfactant include a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. The surfactant may be used alone or in combination of two or more.
The content of the emulsifier is preferably more than 0% by mass and 20% by mass or less, more preferably 0.005 to 10% by mass, and 0.01 to 10 with respect to the total mass of the emulsion which is a mixture of the oil phase and the aqueous phase. The mass% is more preferable, and 1 to 5% by mass is particularly preferable.
The aqueous phase may contain other components such as UV absorbers, antioxidants, and preservatives, if desired.

Dispersion refers to dispersing the oil phase as oil droplets in the aqueous phase (emulsification). Dispersion can be carried out using means commonly used for dispersion between the oil phase and the aqueous phase (eg, homogenizers, manton gorries, ultrasonic dispersers, dissolvers, keddy mills, and other known dispersers).

The mixing ratio of the oil phase to the aqueous phase (oil phase mass / aqueous phase mass) is preferably 0.1 to 1.5, more preferably 0.2 to 1.2, and even more preferably 0.4 to 1.0. ..

-Encapsulation process-
In the encapsulation step, the capsule wall material is polymerized at the interface between the oil phase and the aqueous phase to form a capsule wall, and microcapsules containing a heat storage material are formed.

Polymerization is preferably carried out under heating. The reaction temperature in the polymerization is preferably 40 to 100 ° C, more preferably 50 to 80 ° C. The reaction time of the polymerization is preferably about 0.5 to 10 hours, more preferably about 1 to 5 hours.

In order to prevent the agglutination of the microcapsules during the polymerization, it is preferable to further add an aqueous solution (for example, water, an acetic acid aqueous solution, etc.) to reduce the collision probability between the microcapsules.
It is also preferable to perform sufficient stirring.
Further, a dispersant for preventing aggregation may be added to the reaction system during the polymerization.
Further, if necessary, a charge regulator such as niglocin or any other auxiliary agent may be added to the reaction system during the polymerization.

<Resin>
The heat storage body contains a resin. The resin is located between the above-mentioned microcapsules and functions as a binder for ensuring the adhesion between the microcapsules.
The type of resin is not particularly limited, and examples thereof include known resins.
Examples of the resin include polyurethane, polyurea, polyurethane urea, and poly (meth) acrylate.
Among them, the resin preferably contains at least one resin selected from the group consisting of polyurethane, polyurea, and polyurethane urea, because the effect of the present invention is more excellent.

It is preferable that the capsule wall and the resin of the microcapsules have the same functional group in that the effect of the present invention is more excellent. Among them, it is preferable that the capsule wall and the resin of the microcapsules have the same polar functional group. Examples of the polar functional group include a hydroxyl group, a carboxyl group, an amide group, a urethane group, and a urea group.
Further, in that the effect of the present invention is more excellent, it is preferable that both the capsule wall and the resin of the microcapsules contain at least one selected from the group consisting of polyurethane, polyurea, and polyurethane urea, and the polyurethane urea is used. It is more preferable to include it.

The glass transition temperature of the resin is not particularly limited, but is preferably 50 ° C. or lower, more preferably 40 ° C. or lower, still more preferably 20 ° C. or lower, in that the effect of the present invention is more excellent. The lower limit is not particularly limited, but from the viewpoint of handleability, −100 ° C. or higher is preferable, −60 ° C. or higher is more preferable, and −40 ° C. or higher is further preferable.
The method for measuring the glass transition temperature of the resin is as follows.
The glass transition temperature of the resin is measured from 25 ° C to (heat) at a temperature rise rate of 5 ° C / min using a differential scanning calorimeter DSC (device name: DSC-60A Plus, Shimadzu Corporation) and a closed pan. Measure in the range of decomposition temperature (° C) -5 ° C). As the glass transition temperature of the resin, the value at the time of raising the temperature in the second cycle is used.
When a commercially available product is used as the resin, if the glass transition temperature is described as the catalog value of the commercially available product, that value may be used as the glass transition temperature of the resin.

The elastic modulus (tensile elastic modulus) of the resin is not particularly limited, but is preferably 100 MPa or less, more preferably 15 MPa or less, in that the effect of the present invention is more excellent. The lower limit is not particularly limited, but from the viewpoint of handleability, 0.1 MPa or more is preferable, 1 MPa or more is more preferable, and 6 MPa or more is further preferable.
The method for measuring the elastic modulus (tensile elastic modulus) of the resin is to measure the tensile elastic modulus (Young's modulus) at a temperature of 25 ° C. and a humidity of 40% using a static extensometer according to JIS7161.
When a commercially available product is used as the resin, if the elastic modulus is described as the catalog value of the commercially available product, that value may be used as the elastic modulus of the resin.

The elongation at break of the resin is not particularly limited, but 300% or more is preferable, and 500% or more is more preferable, because the effect of the present invention is more excellent. The upper limit is not particularly limited, but from the viewpoint of handleability, 5000% or less is preferable, and 2000% or less is more preferable.
The method for measuring the breaking elongation of the resin is measured according to JIS-C-2151. Specifically, it is calculated from the elongation when the sample is cut (broken) by tensioning at a speed of 200 mm / min using a tensile tester.
Fracture elongation (%) = 100 × (L-Lo) / Lo
Lo: Sample length before test, L: Sample length at break When using a commercially available resin, if the catalog value of the commercially available product describes the elongation at break, that value. May be used as the breaking elongation of the resin.

At the time of handling, the resin may be used as a dispersion liquid in which the resin is dispersed in a solvent. Examples of the solvent include water and a mixed solution of water and an organic solvent.
When the resin is dispersed in the dispersion liquid, the resin may be in the form of particles. That is, the resin may be used as a latex in which particulate resin is dispersed in water.
The diameter of the particulate resin (resin particles) in the dispersion is not particularly limited, but 0.001 to 10 μm is preferable, and 0.01 to 1 μm is more preferable, because the effect of the present invention is more excellent.

The content of the resin in the heat storage body is not particularly limited, but 20% by mass or less is preferable and 1 to 15% by mass is more preferable with respect to the total mass of the heat storage body in that the heat storage property of the heat storage body is more excellent. Up to 15% by mass is more preferable.

<Water>
The heat storage body may contain water, but when the water contained in the heat storage body evaporates, the portion where the water has evaporated may become a void in the heat storage body. Therefore, the water content in the heat storage body is preferably small from the viewpoint of suppressing the generation of voids. Specifically, the water content in the heat storage body is preferably 5% by mass or less, more preferably 2% by mass or less, based on the total mass of the heat storage body, from the viewpoint of further suppressing the generation of voids in the heat storage body. 1% by mass or less is more preferable.
The lower limit of the water content in the heat storage body is not particularly limited, but may be 0% by mass.
The method for measuring the water content in the heat storage body is as follows. First, the heat storage body is stored in a constant temperature and humidity chamber at 25% RH and 40 ° C. for 24 hours to obtain the heat storage body A. The heat storage body A taken out from the constant temperature and humidity chamber is dried at 100 ° C. for 3 hours to obtain a heat storage body B. The masses of the heat storage body A and the heat storage body B thus obtained are measured, and the value obtained according to the following formula is used as the water content in the heat storage body.
Water content in the heat storage body (mass%) = 100 × {(mass of heat storage body A)-(mass of heat storage body B)} / (mass of heat storage body A)

<Other ingredients>
The heat storage body may contain other components other than the microcapsules and the resin. Other components include thermally conductive materials, flame retardants, UV absorbers, antioxidants, and preservatives.
The content of the other components is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total mass of the heat storage body. The lower limit is not particularly limited, but may be 0% by mass.
Regarding the "thermal conductivity" of the thermally conductive ^{material, a material having a thermal conductivity of 10 Wm -1} K ^-1 or more is preferable. Among them, as the thermal conductivity of the heat conductive material, 50 Wm ^-1 K ^-1 or more is more preferable in terms of improving the heat dissipation of the heat storage body.
The thermal conductivity (unit: Wm ^-1 K ^-1 ) is a value measured by a flash method at a temperature of 25 ° C. by a method compliant with Japanese Industrial Standards (JIS) R1611.

<Physical characteristics of heat storage body>
The shape of the heat storage body is not particularly limited, and it can take any form (three-dimensional shape) such as a cylindrical shape, a spherical shape, and a lump shape as well as a sheet shape, a film shape, and a plate shape.
The effect of the present invention becomes remarkable when the heat storage body is thick, and the thickness of the heat storage body is preferably 0.5 mm or more, more preferably 1 mm or more, and further preferably 2 mm or more. It is preferably 3 mm or more, and particularly preferably 3 mm or more. The upper limit is not particularly limited, but is preferably 1000 mm or less, and more preferably 100 mm or less. The thickness means the shortest distance when the heat storage body is sandwiched between two parallel planes.
However, when the heat storage body is plate-shaped, sheet-shaped, or film-shaped, the thickness of the heat storage body is determined by observing the cut surface of the heat storage body cut in parallel with the thickness direction with SEM and observing 5 arbitrary points. Measure and use the average value of the thicknesses of the five points.

(Latent heat capacity (heat absorption))
The latent heat capacity of the heat storage body is not particularly limited, but 115J / cc or more is preferable, 120J / cc or more is more preferable, and 130J or more is preferable in that the heat storage property of the heat storage body is high and it is suitable for temperature control of the heat generating body that generates heat. / Cc or more is more preferable. The upper limit is not particularly limited, but is preferably 300 J / cc or less.
The latent heat capacity is a value calculated from the result of differential scanning calorimetry (DSC) and the density of the heat storage body (g / cm ^3).
The density is measured from the mass and volume of the sample. The mass of the sample is measured with an electronic balance. The volume of the sample is calculated by measuring the area and thickness with a caliper, a contact type thickness measuring machine, etc. when the sample is in the form of a sheet, and when the sample is in the form of a lump, a solvent that does not dissolve or swell. Obtained from the increased volume by immersing in (water, alcohol, etc.).
Considering that a high amount of heat storage is exhibited in a limited space, it is considered appropriate to grasp the amount of heat storage as "J / cc", but when considering the use of electronic devices, etc., The weight of the electronic device is also important. Therefore, if we consider that high heat storage is exhibited within a limited mass, it may be appropriate to consider it as "J / g (heat storage amount per unit mass)". In this case, the latent heat capacity is preferably 150 J / g or more, more preferably 160 J / g or more. The upper limit is not particularly limited, but is preferably 300 J / g or less.

(Volume fraction of microcapsules)
The volume ratio of the microcapsules in the heat storage body is not particularly limited, but is preferably 60% by volume or more, more preferably 80% by volume or more, still more preferably 90% by volume or more, based on the total volume of the heat storage body. The upper limit is not particularly limited, but 100% by volume or less can be mentioned.

(Porosity)
The porosity of the heat storage body means the volume fraction of the voids in the heat storage body. Here, the void means a region inside the heat storage body in which the material (solid and liquid) constituting the heat storage body does not exist and is surrounded by the material constituting the heat storage body, and is usually a gas (mainly). Is filled with air).
The void ratio of the heat storage body is less than 10% by volume with respect to the total volume of the heat storage body, and is preferably 6% by volume or less, preferably 5% by volume or less, from the viewpoint of further suppressing the occurrence of defects in the heat storage body during handling. Is more preferable. The lower limit of the porosity of the heat storage body is not particularly limited, but may be 0% by volume.
Further, when the porosity of the heat storage body is less than 10% by volume, the amount of heat storage per unit volume can be further improved.
The method of reducing the porosity of the heat storage body to less than 10% by volume is not particularly limited, but the material and resin of the capsule wall of the microcapsules are the same while using the microcapsules having a thin wall thickness and a high deformation rate. Examples thereof include a method of adjusting to have a functional group.

The void ratio of the heat storage body is calculated based on image data obtained by a known X-ray CT apparatus using an X-ray CT (X-ray Computed Tomography) method as a measurement principle.
Specifically, an arbitrary region of 1 mm × 1 mm in the in-plane direction of the heat storage body is scanned along the film thickness direction of the heat storage body by the X-ray CT method, and the gas (air) and the others (solid and solid) are scanned. Distinguish from liquid). Then, from the three-dimensional image data obtained by image processing a plurality of scanning layers obtained by scanning along the film thickness direction, the volume of the gas (void portion) existing in the scanned region and the scanned region are obtained. (Total volume of gas, solid and liquid) and the total volume of. Then, the ratio of the volume of the gas to the total volume of the scanned regions is defined as the porosity (volume%) of the heat storage body.

(Aspect ratio of microcapsules)
As described above, the microcapsules contained in the heat storage body are preferably deformed. Among them, the aspect ratio of the microcapsules is preferably 1.2 or more, more preferably 1.5 or more, and even more preferably 2.0 or more.
When the aspect ratio of the microcapsules is within the above range, the filling rate of the microcapsules is improved, the contact area between the microcapsules is widened, the strength of the heat storage body is improved, and defects of the heat storage body are generated during handling. Can be further suppressed. Further, by improving the filling rate of the microcapsules, the amount of the heat storage material can be increased, and more excellent heat storage can be realized.
The upper limit of the aspect ratio of the microcapsules is not particularly limited, but may be, for example, 10 or less.

The aspect ratio of the microcapsules can be obtained by the following method from the SEM cross-sectional image of the heat storage body. After observing the cross section of the heat storage body using SEM and obtaining an SEM cross section image, 20 microcapsules are selected from the obtained images. Of the two parallel tangents circumscribing the outer circumference of each selected microcapsule, the distance between the two parallel tangents selected so as to maximize the distance between the tangents is defined as the length L of the long side. Further, of the two parallel tangents orthogonal to the two parallel tangents giving the length L and circumscribing the outer circumference of the microcapsule, the distance between the tangents selected so as to maximize the distance between the tangents is selected. Let the length of the short side be S. From the obtained long side length L (μm) and short side length S (μm), the aspect ratio was calculated using the following formula, and the average value of the aspect ratios of 20 microcapsules was obtained. The obtained average value is used as the aspect ratio of the microcapsules.
Aspect ratio = L (μm) / S (μm)
As an example of the method of keeping the aspect ratio of the microcapsules within the above range, the method described as a method of reducing the porosity of the heat storage body can be mentioned.

(Shape of microcapsules)
Further, the microcapsules contained in the heat storage body preferably have flat portions or recesses formed by contact with other microcapsules or the like.
Specifically, it is preferable that the microcapsules in the heat storage body observed by the following method have two or more flat portions and recesses. After obtaining an SEM cross-sectional image by the same method as the aspect ratio calculation method described above, 20 microcapsules are selected. Then, from the SEM cross-sectional image, the selected microcapsules form a portion in which at least two or more microcapsules are adjacent to each other, and in the outer shape of the selected microcapsules, the outer shape of the adjacent microcapsules. It is confirmed whether or not the condition of having two or more linear or concave portions formed along the above condition is satisfied. Of the 20 selected microcapsules, the number of microcapsules satisfying the above conditions is preferably 5 or more, more preferably 10 or more, and even more preferably 20.

(Elastic modulus)
The elastic modulus (tensile elastic modulus) of the heat storage body is not particularly limited, but is preferably 50 MPa or more, more preferably 100 MPa or more, further preferably 500 MPa or more, and particularly preferably 1000 MPa or more.
The upper limit of the elastic modulus of the heat storage body is not particularly limited, but is preferably 10,000 MPa or less.
The elastic modulus (tensile elastic modulus) of the heat storage body is measured according to JIS K 7161-1: 2014.

<Manufacturing method of heat storage body>
The method for producing the heat storage body is not particularly limited, and a known method can be mentioned. For example, a method of producing a heat storage body by using the above-mentioned microcapsule, a resin, and a composition for forming a heat storage body containing water can be mentioned. More specifically, for example, a method for producing a heat storage body by applying the heat storage body forming composition on a predetermined substrate and drying it, forming the heat storage body in a gap between members. A method of filling a heat storage composition and drying it to produce a heat storage body, a method of dropping a heat storage body forming composition onto a substrate to form a lump, and a mold for the heat storage body forming composition. There is a method of molding by putting it in a heat storage.
If necessary, the base material can be peeled off from the laminate of the obtained base material and the heat storage body to obtain a simple substance of the heat storage body.

The microcapsules and the resin contained in the composition for forming a heat storage body are as described above.
The method for preparing the composition for forming a heat storage body is not particularly limited, and for example, a dispersion liquid in which microcapsules are dispersed (for example, an aqueous dispersion liquid) and a dispersion liquid in which particulate resin is dispersed (for example, an aqueous dispersion liquid, so-called). , Latex.), And a method of mixing powdery microcapsules and a dispersion liquid in which particulate resin is dispersed.
Examples of the method for obtaining powdered microcapsules include a method for recovering microcapsules by removing a solvent from the above-mentioned dispersion liquid in which microcapsules are dispersed. The method for recovering the microcapsules is not particularly limited, and examples thereof include a method for recovering the microcapsules in the dispersion liquid in which the microcapsules are dispersed by decantation.

Examples of the base material include a resin base material, a glass base material, and a metal base material. Examples of the resin contained in the resin base material include polyester (eg, polyethylene terephthalate, polyethylene naphthalate), polyolefin (eg, polyethylene, polypropylene), and polyurethane. Further, it is preferable to add a function to improve the thermal conductivity in the in-plane direction or the film thickness direction and to quickly dissipate heat from the heat generating portion to the heat storage portion to the base material. As the base material, a base material made by combining a metal base material and a heat conductive material such as a graphite sheet or a graphene sheet is more preferable.
The thickness of the base material is not particularly limited, but is preferably 1 to 100 μm, more preferably 1 to 25 μm, still more preferably 3 to 15 μm.
The base material is preferably treated on the surface of the base material for the purpose of improving the adhesion to the heat storage body. Examples of the surface treatment method include corona treatment, plasma treatment, and application of a thin layer which is an easy-adhesion layer.

The material constituting the easy-adhesion layer is not particularly limited, and examples thereof include resin, and more specific examples thereof include styrene-butadiene rubber, urethane resin, acrylic resin, silicone resin, and polyvinyl resin.
The thickness of the easy-adhesion layer is not particularly limited, but is preferably 0.01 to 5 μm, more preferably 0.5 to 2 μm.

As the base material, a peelable temporary base material may be used.

Examples of the coating method include a die coating method, an air knife coating method, a roll coating method, a blade coating method, a gravure coating method, and a curtain coating method.

The preferable range of the drying temperature depends on the amount of water at the time of drying, but when water is contained in the composition for forming the heat storage body, 20 to 130 ° C. is preferable because the porosity of the heat storage body can be further lowered. , 30 to 120 ° C. is more preferable, and 33 to 100 ° C. is even more preferable.
The drying time is preferably completed immediately before the moisture in the membrane is completely dried, but in that range, 30 seconds or more is preferable and 1 minute or more is more preferable from the viewpoint that the porosity of the heat storage body can be further lowered. The shorter the upper limit of the drying time, the better from the viewpoint of the production efficiency of the heat storage body.
In the step of drying, the coating film may be subjected to a flattening treatment. Examples of the flattening treatment method include a method of applying pressure to the coating film with a roller, a nip roller, a calendar, or the like to increase the filling rate of microcapsules in the film.

Further, in order to reduce the porosity in the heat storage body, use microcapsules that are easily deformed (large deformation rate), slowly dry the coating film, or thicken the film at one time. It is preferable to apply the coating film in a plurality of times without forming a suitable coating film.

[Use of heat storage body]
The heat storage body of the present invention can be applied to various uses, for example, electronic devices (for example, mobile phones (particularly smartphones), mobile information terminals, personal computers (particularly portable personal computers), game machines, and (Remote control, etc.); Automobiles (for example, batteries (particularly lithium ion batteries), control devices such as power ICs (Integrated Circuits), car navigation systems, liquid crystal monitors, LED (Light Emitting Diode) lamps, heat insulation of canisters, etc.); Building materials suitable for temperature control during rapid temperature rise in the room or indoor heating and cooling (for example, floor materials, roofing materials, wall materials, etc.); Changes in environmental temperature or changes in body temperature during exercise or rest, etc. Clothes suitable for temperature control according to the temperature (for example, underwear, jacket, cold protection clothes, gloves, etc.); Air conditioner; Bedding; Exhaust heat utilization system that stores unnecessary exhaust heat and uses it as heat energy, etc. Can be used for.

Above all, it is preferable to use it for an electronic device (particularly, a portable electronic device). The reason for this is as follows.
As a method of suppressing the temperature rise due to heat generation of the electronic device, a method of discharging heat to the outside of the electronic device by the flow of air and a method of diffusing the heat to the entire housing of the electronic device by a heat pipe or a heat spreader are used. Has been done. However, from the viewpoint of thinning and waterproofing of electronic devices in recent years, the airtightness of electronic devices has improved, and it is difficult to adopt a method of discharging heat by the flow of air. Then, a method of diffusing heat to the entire housing of the electronic device is used. Therefore, there is a limit to suppressing the temperature rise of the electronic device.
To solve this problem, by introducing the above-mentioned heat storage body into the electronic device, it is possible to suppress the temperature rise of the electronic device while maintaining the airtightness and waterproofness of the electronic device. That is, since the heat storage body creates a portion in the electronic device where heat can be stored for a certain period of time, the surface temperature of the heating element in the electronic device can be maintained in an arbitrary temperature range.

[Heat storage member]
The heat storage member of the present invention has the above-mentioned heat storage body.
When the heat storage body is in the form of a sheet, a plate, or a film, the heat storage member preferably has another layer (for example, a protective layer) as described later. Further, when the heat storage body is in the form of a sheet, a plate, or a film, the heat storage member may have a base material on the heat storage body in terms of handling.

<Protective layer>
When the heat storage body is in the form of a sheet, a plate, or a film, the heat storage member may have a protective layer. The protective layer is a layer arranged on the heat storage body, and when the heat storage member has a base material, the protective layer is arranged on the surface side of the heat storage body opposite to the base material. The protective layer has a function of protecting the heat storage body.
The protective layer may be arranged so as to be in contact with the heat storage body, or may be arranged on the heat storage body via another layer.
The material constituting the protective layer is not particularly limited, and a resin is preferable, and a resin selected from the group consisting of a fluororesin and a siloxane resin is preferable in that water resistance and flame retardancy are better.

Examples of the fluororesin include known fluororesins. Examples of the fluororesin include polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene trifluorochloride, and polytetrafluoropropylene.
The fluororesin may be a homopolymer obtained by polymerizing a single monomer, or may be a copolymer of two or more types. Further, a copolymer of these monomers and other monomers may be used.
Examples of the copolymer include a copolymer of tetrafluoroethylene and tetrafluoropropylene, a copolymer of tetrafluoroethylene and vinylidene fluoride, a copolymer of tetrafluoroethylene and ethylene, and tetrafluoroethylene and propylene. Polymers with, tetrafluoroethylene and vinyl ether copolymers, tetrafluoroethylene and perfluorovinyl ether copolymers, chlorotrifluoroethylene and vinyl ether copolymers, and chlorotrifluoroethylene and per. Examples thereof include a polymer with fluorovinyl ether.
Examples of the fluororesin include Obligato (registered trademark) SW0011F, SIFCLEAR-F101, F102 (manufactured by JSR), KYNAR AQUATEC (registered trademark) ARC, and FMA-12 (both manufactured by Arkema) manufactured by AGC Cortec. ..

The siloxane resin is a polymer having a repeating unit having a siloxane skeleton, and a hydrolyzed condensate of a compound represented by the following formula (1) is preferable.
Equation (1) Si (X) _n (R) _4-n
X represents a hydrolyzable group. Examples of the hydrolyzable group include an alkoxy group, a halogen group, an acetoxy group, and an isocyanate group.
R represents a non-hydrolyzable group. Examples of the non-hydrolytable group include an alkyl group (for example, a methyl group, an ethyl group, and a propyl group), an aryl group (for example, a phenyl group, a trill group, and a mesityl group), and an alkenyl group (for example, vinyl). Group and allyl group), haloalkyl group (eg γ-chloropropyl group), aminoalkyl group (eg γ-aminopropyl group and γ- (2-aminoethyl) aminopropyl group), epoxyalkyl group (For example, γ-glycidoxypropyl group and β- (3,4-epoxycyclohexyl) ethyl group), γ-mercaptoalkyl group, (meth) acryloyloxyalkyl group (γ-methacryloyloxypropyl group), and , A hydroxyalkyl group (eg, γ-hydroxypropyl group).
n represents an integer of 1 to 4, preferably 3 or 4.
The hydrolyzed condensate is intended to be a compound obtained by hydrolyzing a hydrolyzable group in the compound represented by the formula (1) and condensing the obtained hydrolyzate. The hydrolyzed condensate may be partially hydrolyzed even if all hydrolyzable groups are hydrolyzed and all the hydrolyzated products are condensed (completely hydrolyzed condensate). The sex group may be hydrolyzed and a part of the hydrolyzate may be condensed (partially hydrolyzed condensate). That is, the hydrolyzed condensate may be a completely hydrolyzed condensate, a partially hydrolyzed condensate, or a mixture thereof.

As the protective layer, for example, a layer containing a known hard coat agent or a hard coat film described in JP-A-2018-202696, JP-A-2018-18387, and JP-A-2018-111793 may be used. good. Further, from the viewpoint of heat storage property, a protective layer having a polymer having heat storage property described in International Publication No. 2018/207387 and JP-A-2007-031610 may be used.

The protective layer may contain components other than the resin. Other components include thermally conductive materials, flame retardants, UV absorbers, antioxidants, and preservatives.

The flame retardant is not particularly limited, and a known material can be used. For example, a flame retardant or the like described in "Techniques for Utilizing Flame Retardants / Flame Retardants" (CMC Publishing) can be used, and halogen-based flame retardants, phosphorus-based flame retardants, or inorganic flame retardants are preferable. When it is desirable to suppress the mixing of halogens in electronic applications, phosphorus-based flame retardants or inorganic flame retardants are preferable.
Phosphorus-based flame retardants include phosphate-based materials such as triphenyl phosphate, tricresyl phosphate, trixilenyl phosphate, cresylphenyl phosphate, and 2-ethylhexyldiphenyl phosphate, other aromatic phosphate esters, and aromatic condensed phosphorus. Examples thereof include acid esters, polyphosphates, phosphinic acid metal salts, and red phosphorus.
It is also preferable to include a flame retardant aid in combination with the flame retardant. Examples of the flame retardant aid include pentaerythritol, phosphorous acid, and 22-oxidized tetrasalt 12boron heptahydrate.

The thickness of the protective layer is not particularly limited, but is preferably 50 μm or less, more preferably 0.01 to 25 μm, still more preferably 0.5 to 15 μm.
For the thickness, the cut surface obtained by cutting the protective layer in parallel with the thickness direction is observed by SEM, 5 arbitrary points are measured, and the thickness of the 5 points is averaged.

The method for forming the protective layer is not particularly limited, and known methods can be mentioned. For example, a method in which a protective layer forming composition containing a resin or a precursor thereof is brought into contact with a heat storage body, and a coating film formed on the heat storage body is subjected to a curing treatment as necessary, and protection. A method of bonding the layers on the heat storage body can be mentioned.
Hereinafter, the method of using the composition for forming a protective layer will be described in detail.

The resin contained in the protective layer forming composition is as described above.
The resin precursor means a component that becomes a resin by curing treatment, and examples thereof include a compound represented by the above-mentioned formula (1).
The composition for forming a protective layer may contain a solvent (for example, water and an organic solvent), if necessary.

The method of contacting the protective layer forming composition with the heat storage body is not particularly limited, and the method of applying the protective layer forming composition onto the heat storage body and the method of immersing the heat storage body in the protective layer forming composition are immersed. The method can be mentioned.
As a method for applying the protective layer forming composition, a dip coater, a die coater, a slit coater, a bar coater, an extrusion coater, a curtain flow coater, a known coating device such as spray coating, and gravure printing are used. , Screen printing, offset printing, and a method using a printing device such as inkjet printing.

<Adhesion layer>
When the heat storage body is in the form of a sheet, a plate, or a film, an adhesion layer is arranged on the side opposite to the heat storage body of the base material for the purpose of improving the adhesion between the heating element and the heat storage element, which will be described later. You may. Examples of the adhesive layer include an adhesive layer and an adhesive layer.
The material of the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include known pressure-sensitive adhesives.
Examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive. Further, as an example of the adhesive, "Characteristic evaluation of release paper / release film and adhesive tape and its control technology", Information Mechanism, 2004, acrylic adhesive described in Chapter 2, ultraviolet curable adhesive, and , Silicone adhesive and the like.
The acrylic pressure-sensitive adhesive refers to a pressure-sensitive adhesive containing a polymer of (meth) acrylic monomer ((meth) acrylic polymer).
The adhesive layer may further contain a tackifier.

The material of the adhesive layer is not particularly limited, and examples thereof include known adhesives.
Examples of the adhesive include urethane resin adhesives, polyester adhesives, acrylic resin adhesives, ethylene vinyl acetate resin adhesives, polyvinyl alcohol adhesives, polyamide adhesives, and silicone adhesives.

The method for forming the adhesion layer is not particularly limited, and for example, a method of transferring the adhesion layer onto the heat storage body and a method of applying a composition containing an adhesive or an adhesive onto the heat storage body to form the adhesion layer. Can be mentioned.
The thickness of the adhesion layer is not particularly limited, but is preferably 0.5 to 100 μm, more preferably 1 to 25 μm, still more preferably 1 to 15 μm.

<Flame-retardant layer>
When the heat storage body is in the form of a sheet, a plate, or a film, the heat storage member may have a flame-retardant layer. Further, the heat storage body may have a flame-retardant component. The position of the flame-retardant layer is not particularly limited, and may be integrated with the protective layer or may be provided as a separate layer. When it is provided as a separate layer, it is preferably laminated between the protective layer and the heat storage body. When it is integrated with the protective layer, it means that the protective layer has a flame-retardant function. In particular, when the latent heat storage material is a flammable material such as paraffin, the entire heat storage member can be made flame-retardant by having a flame-retardant protective layer or a flame-retardant layer.
The flame-retardant protective layer and the flame-retardant layer are not particularly limited as long as they are flame-retardant, but are flame-retardant organic resins such as polyetheretherketone resin, polycarbonate resin, silicone resin, and fluorine-containing resin, as well. , It is preferably formed from an inorganic material such as a glass film. Here, the glass film can be formed by, for example, applying a silane coupling agent or a siloxane oligomer on a heat storage body and heating or drying the glass film.
As a method for forming the flame retardant protective layer, a flame retardant may be mixed and formed in the protective layer. As the flame retardant, the above-mentioned flame retardant and inorganic particles such as silica are preferable. The amount and type of the inorganic particles can be adjusted including the type of the resin depending on the surface shape and / or the film quality. The size of the inorganic particles is preferably 0.01 to 1 μm, more preferably 0.05 to 0.3 μm, still more preferably 0.1 to 0.2 μm.
The content of the inorganic particles is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, based on the total mass of the protective layer.
The content of the flame retardant is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, and 1 to 5% by mass with respect to the total mass of the protective layer from the viewpoint of heat storage amount and flame retardancy. Is more preferable. The thickness of the flame-retardant protective layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and even more preferably 0.5 to 10 μm from the viewpoint of heat storage amount and flame retardancy.

<Colored layer>
When the heat storage body is in the form of a sheet, a plate, or a film, the heat storage member may have a colored layer. Further, the heat storage body may have a coloring component. By providing the colored layer, it is possible to suppress the change in the appearance of the heat storage member even when the color of the heat storage body changes. In addition, rubbing during handling or invasion of water or the like into the heat storage body can be suppressed, physical or chemical changes in the microcapsules can be suppressed, and as a result, color change of the heat storage body itself can be suppressed.
The colored layer may be integrated with the protective layer, or may be arranged as a separate layer so as to be in contact with the heat storage body.

The colored layer preferably contains a colorant in order to obtain the desired hue.
Examples of the colorant include pigments and dyes, and pigments are preferable, black pigments are more preferable, and carbon black is further preferable, because they have excellent weather resistance and can further suppress the change in the appearance of the heat storage member. preferable. When carbon black is used, the thermal conductivity of the colored layer is further improved.
Examples of the pigment include various conventionally known inorganic pigments and organic pigments.
Specific examples of the inorganic pigment include white pigments such as titanium dioxide, zinc oxide, lithopone, light calcium carbonate, white carbon, aluminum oxide, aluminum hydroxide, and barium sulfate, and carbon black, titanium black, and titanium. Examples thereof include black pigments such as carbon, iron oxide, and graphite.

Examples of the organic pigment include the organic pigment described in paragraph 0093 of JP-A-2009-256572.
Examples of the organic pigment include C.I. I. Pigment Red 177, 179, 224, 242, 254, 255, 264 and other red pigments, C.I. I. Pigment Yellow 138, 139, 150, 180, 185 and other yellow pigments, C.I. I. Pigment Orange 36, 38, 71 and other orange pigments, C.I. I. Pigment Green 7, 36, 58 and other green pigments, C.I. I. Blue pigments such as Pigment Blue 15: 6 and C.I. I. Examples include purple pigments such as Pigment Violet 23.
The colorant may be used alone or in combination of two or more.

The content of the colorant (for example, black pigment) in the colored layer is not particularly limited, but is 2 to 30% by volume with respect to the total volume of the colored layer in that the change in the appearance of the heat storage member can be further suppressed. It is preferable, 5 to 25% by volume is more preferable.

The colored layer may contain a binder.
The type of the binder is not particularly limited, and known materials can be mentioned, and a resin is preferable.
As the resin, a resin selected from the group consisting of fluororesins and siloxane resins is preferable because it has better water resistance and flame retardancy. By including the resin selected from the group consisting of fluororesin and siloxane resin having good water resistance in the colored layer, the chemical change of the microcapsules can be suppressed and the color change of the heat storage body can be suppressed.
Specific examples of the fluororesin and the siloxane resin are as described above.

The content of the binder in the colored layer is not particularly limited, but is preferably 50 to 98% by volume, preferably 75 to 95% by volume, based on the total volume of the colored layer, in that the change in the appearance of the heat storage member can be further suppressed. Is more preferable.
The binder in the colored layer may be used alone or in combination of two or more.

The colored layer may contain other components other than the colorant and the binder. Other components include thermally conductive materials, flame retardants, UV absorbers, antioxidants, and preservatives.

The thickness of the colored layer is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 0.5 to 10 μm.
For the thickness, the cut surface obtained by cutting the colored layer in parallel with the thickness direction is observed by SEM, 5 arbitrary points are measured, and the thickness of the 5 points is averaged.

One of the preferred forms of the colored layer is a form in which the film thickness of the colored layer is 15 μm or less and the optical density of the colored layer is 1.0 or more. When the optical density is in the above range, even when the colored layer is thin, the change in the appearance of the heat storage member can be further suppressed.
The optical density is preferably 1.2 or more. The upper limit is not particularly limited, but 6.0 or less is preferable.
As the method for measuring the optical density, X-rite eXact (manufactured by X-Rite) is used, and the density status is measured at ISO status T and D50 / 2 ° without a filter. As the optical density, the K value is adopted as the OD value of Xrite.

The method for forming the colored layer is not particularly limited, and known methods can be mentioned. For example, there is a method in which a composition for forming a colored layer containing a colorant and a binder or a precursor thereof is brought into contact with a heat storage body, and a coating film formed on the heat storage body is subjected to a curing treatment as necessary. Can be mentioned.
Hereinafter, the above method will be described in detail.

The colorants and binders contained in the composition for forming a colored layer are as described above.
The precursor of the binder contained in the composition for forming a colored layer means a component that becomes a binder by a curing treatment, and examples thereof include a compound represented by the above-mentioned formula (1).
The colored layer forming composition may contain a solvent (for example, water and an organic solvent), if necessary.

The method of contacting the colored layer forming composition with the heat storage body is not particularly limited, and the method of applying the colored layer forming composition onto the heat storage body and the method of immersing the heat storage body in the colored layer forming composition are immersed. The method can be mentioned.
The method of applying the composition for forming a colored layer is the same as the method described in the method of applying the composition for forming a protective layer.
The colored layer may be provided on the entire surface of the heat storage body, or may be provided in a pattern on a part thereof.

<Other members>
When the heat storage member is in the form of a sheet, a plate, or a film, the heat storage member has a base material arranged on the surface side opposite to the protective layer in the heat storage body and a surface opposite to the heat storage body in the above base material. It may have an adhesion layer arranged on the side and a temporary substrate arranged on the surface side of the adhesion layer opposite to the substrate. As a result, it is possible to suppress damage to the heat storage body during storage and transportation of the heat storage member.
The base material and the adhesive layer are as described above. Moreover, the specific example of the temporary base material is the same as the specific example of the base material. It is preferably a base material having a peeled surface.
When using the heat storage member, the temporary base material is peeled off from the heat storage member.

[Electronic device]
The electronic device of the present invention has the above-mentioned heat storage member or heat storage body and a heating element.
The heat storage member is as described above.

<Heating element>
The heating element is a member that may generate heat in an electronic device, and is, for example, a SoC such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a SRAM (Static Random Access Memory), and an RF (Radio Frequency) device. (Systems on a Chip), cameras, LED packages, power electronics, and batteries (especially lithium ion secondary batteries).
The heating element may be arranged so as to be in contact with the heat storage member, or may be arranged on the heat storage member via another layer (for example, a heat conductive material described later).

<Thermal conductive material>
The electronic device further preferably has a thermally conductive material.
The heat conductive material means a material having a function of conducting heat generated from a heating element to another medium.
As the "thermal conductivity" of the thermally conductive material, it is preferable that ^{the thermal conductivity is 10 Wm -1} K ^{-1 or more.} That is, the heat conductive material is preferably a material having a thermal conductivity of 10 Wm ^-1 K ^-1 or more. The thermal conductivity (unit: Wm ^-1 K ^-1 ) is a value measured by a flash method at a temperature of 25 ° C. by a method compliant with Japanese Industrial Standards (JIS) R1611.
Examples of the heat conductive material that the electronic device may have include a metal plate, a heat radiating sheet, and silicon grease, and a metal plate or a heat radiating sheet is preferably used.
The electronic device preferably has the above-mentioned heat storage member, a heat conductive material arranged on the heat storage member, and a heating element arranged on the surface side of the heat conductive material opposite to the heat storage member. Further, it is more preferable that the electronic device has the above-mentioned heat storage member, a metal plate arranged on the heat storage member, and a heating element arranged on the surface side of the metal plate opposite to the heat storage member.
When the above-mentioned heat storage member has a protective layer, one of the preferred embodiments of the electronic device is a above-mentioned heat storage member, a metal plate arranged on the surface side of the above-mentioned heat storage member opposite to the above-mentioned protective layer, and the above-mentioned heat storage member. An embodiment having a heating element arranged on the surface side of the metal plate opposite to the heat storage member can be mentioned. In other words, it is preferable that the protective layer, the heat storage body, the metal plate, and the heat generating body are laminated in this order.

(Metal plate)
The metal plate has a function of protecting the heating element and conducting heat generated from the heating element to the heat storage element.
The surface of the metal plate opposite to the surface on which the heating element is provided may be in contact with the heat storage element, or heat may be stored via another layer (for example, a heat dissipation sheet, an adhesion layer, or a base material). The body may be arranged.
Examples of the material constituting the metal plate include aluminum, copper, and stainless steel.

(Heat dissipation sheet)
The heat radiating sheet is a sheet having a function of conducting heat generated from a heating element to another medium, and preferably has a heat radiating material. Examples of the heat radiating material include carbon, metal (for example, silver, copper, aluminum, iron, platinum, stainless steel, and nickel), and silicon.
Specific examples of the heat radiating sheet include a copper foil sheet, a metal film resin sheet, a metal-containing resin sheet, and a graphene sheet, and a graphene sheet is preferably used. The thickness of the heat radiating sheet is not particularly limited, but is preferably 10 to 500 μm, more preferably 20 to 300 μm.

<Heat pipe, vapor chamber>
The electronic device preferably further comprises a heat transport member selected from the group consisting of heat pipes and vapor chambers.
Both the heat pipe and the vapor chamber are made of metal or the like and include at least a member having a hollow structure and a working fluid which is a heat transfer medium enclosed in the internal space thereof, and the working fluid in a high temperature part (evaporation part). Evaporates (vaporizes) and absorbs heat, and the vaporized working fluid condenses in the low temperature part (condensed part) and releases heat. The heat pipe and the vapor chamber have a function of transporting heat from a member in contact with a high temperature portion to a member in contact with a low temperature portion due to a phase change of the working fluid inside the heat pipe and the vapor chamber.

When the electronic device has a heat storage member and a heat transport member selected from the group consisting of a heat pipe and a vapor chamber, it is preferable that the heat storage member and the heat pipe or the vapor chamber are in contact with each other, and the heat storage member is a heat pipe. Alternatively, it is more preferable that the vapor chamber is in contact with the low temperature portion.
Further, when the electronic device has a heat storage member and a heat transport member selected from the group consisting of a heat pipe and a vapor chamber, the phase change temperature of the heat storage material contained in the heat storage body of the present invention possessed by the heat storage member and heat. It is preferable that the temperature range in which the pipe or vapor chamber operates overlaps. The temperature range in which the heat pipe or the vapor chamber operates includes, for example, a range of temperatures in which the working fluid can undergo a phase change.

The heat pipe has at least a tubular member and a working fluid enclosed in its internal space. The heat pipe preferably has a wick structure on the inner wall of the tubular member as a flow path for the working fluid based on the capillary phenomenon, and has a cross-sectional structure in which an internal space for the passage of the vaporized working fluid is provided inside the wick structure. .. Examples of the shape of the tubular member include a circular tube, a square tube, and a flat elliptical tube. The tubular member may have a bent portion. Further, the heat pipe may be a loop heat pipe having a structure in which tubular members are connected in a loop shape.

The vapor chamber has at least a flat plate-shaped member having a hollow structure and a working fluid enclosed in the internal space thereof. The vapor chamber preferably has a wick structure similar to that of a heat pipe on the inner surface of a flat plate-shaped member. In the vapor chamber, heat is generally absorbed from a member in contact with one main surface of the flat plate-shaped member, and heat is released to the member in contact with the other main surface to transport heat.

The material constituting the heat pipe and the vapor chamber is not particularly limited as long as it is a material having high thermal conductivity, and examples thereof include metals such as copper and aluminum.
Examples of the working fluid enclosed in the internal space of the heat pipe and the vapor chamber include water, methanol, ethanol and CFC substitutes, which are appropriately selected and used according to the temperature range of the electronic device to be applied.

<Other members>
The electronic device may include a protective layer, a heat storage body, a heat conductive material, a heating element, and other members other than the heat transport member described above. Examples of other members include a base material and an adhesion layer. The base material and the adhesive layer are as described above.

The electronic device may have at least one member selected from the group consisting of a heat radiating sheet, a base material, and an adhesion layer between the heat storage body and the metal plate. When two or more members of the heat dissipation sheet, the base material, and the close contact layer are arranged between the heat storage body and the metal plate, the base material and the close contact are made from the heat storage body side toward the metal plate side. It is preferable that the layers and the heat dissipation sheets are arranged in this order.
Further, the electronic device may have a heat radiating sheet between the metal plate and the heating element.

The specific examples of the electronic device are as described above, so the description thereof will be omitted.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist is not exceeded.

<Example 1>
(Preparation of microcapsule dispersion)
100 parts by mass of icosane (latent heat storage material; an aliphatic hydrocarbon having a melting point of 37 ° C. and 20 carbon atoms) was heated and dissolved at 60 ° C. to obtain a solution A to which 120 parts by mass of ethyl acetate was added.
Next, 0.1 part by mass of N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine (ADEKApolyether EDP-300, ADEKA CORPORATION) is added to the stirring solution A to make a solution. B was obtained.
Further, 10 parts by mass of an adduct of trimethylolpropane and trimethylolpropane dissolved in 1 part by mass of methyl ethyl ketone (Bernock D-750, DIC Corporation) was added to the stirring solution B to obtain a solution C.
Then, the above solution C is added to a solution prepared by dissolving 10 parts by mass of polyvinyl alcohol (Kuraray (registered trademark) KL-318 (manufactured by Kuraray Co., Ltd .; PVA (Polyvinyl alcohol))) as an emulsifier in 140 parts by mass of water. And emulsified and dispersed. 250 parts by mass of water was added to the emulsified liquid after emulsification and dispersion, and the obtained solution was heated to 70 ° C. while stirring, and after continuing stirring for 1 hour, it was cooled to 30 ° C. Water was further added to the cooled solution to adjust the concentration to obtain an icosane-encapsulating microcapsule dispersion having a polyurethane urea capsule wall.
The solid content concentration of the microcapsule dispersion containing Eikosan was 19% by mass. The mass of the capsule wall of the icosane-encapsulated microcapsules was 10% by mass with respect to the mass of the encapsulated icosane. The median diameter of the microcapsules on a volume basis was 20 μm. The thickness of the capsule wall of the microcapsules was 0.1 μm.
Further, the deformation rate of the microcapsules taken out from the obtained dispersion was measured by the above method using an HM2000 type microhardness meter manufactured by Fisher Instruments Co., Ltd. as an indentation hardness tester. As a result, the deformation rate of the microcapsules was obtained. Was 41%.

(Preparation of microcapsule powder)
Water (800 parts by mass) was added to the Eikosan-encapsulating microcapsule dispersion (100 parts by mass), and after stirring for 30 minutes, the mixture was allowed to stand at 80 ° C. for 4 hours to form an upper layer in which the microcapsules aggregated and a lower layer which is an aqueous phase. Separated into. Polyvinyl alcohol, which is an emulsifier not adsorbed on the microcapsules, was dissolved in the lower layer, which is the aqueous phase.
Then, after removing the lower layer which is the aqueous phase, water (800 parts by mass) is added to the remaining solid content (microcapsule aggregates), the mixture is stirred for 30 minutes, and allowed to stand at 80 ° C. for 4 hours to aggregate the microcapsules. After separating the upper layer and the lower layer which is the aqueous phase, the operation of removing the lower layer which is the aqueous phase was repeated four times. The obtained microcapsule agglomerates were wrapped in a non-woven fabric and dried by applying cold air while rubbing to obtain microcapsule powder.

(Preparation of composition for forming heat storage body)
Superflex E2000 (3.9 parts by mass) and water (1.3 parts by mass) were added to the microcapsule powder (13.3 parts by mass), and the mixture was stirred with a mix rotor for 4 hours. Then, in the obtained solution, an aqueous solution of carbonyl EP (concentration of carbonyl EP with respect to the total mass of the aqueous solution: 1% by mass) (1.2 parts by mass) and sodium-1,2- (bis (3,3,4,4) , 5, 5, 6, 6, 6-Nanofluorohexylcarbonyl)) Ethanesulfonate (hereinafter, also referred to as "Compound A") Aqueous solution (Concentration of Compound A with respect to the total mass of the aqueous solution: 2% by mass) (0.23) By mass) was added, and the mixture was stirred with a mix rotor for 4 hours to obtain a heat storage body forming composition 1.
Then, the obtained heat storage body forming composition 1 (5 cc) was dropped onto a release film, dried at 85 ° C. for 2 hours to a size of 30 mm in diameter, and the heat storage body without cracks (thickness: 5400 μm). ) Was manufactured.
The porosity of the obtained heat storage body was 5% by volume. The heat absorption amount of the heat storage body was 160 J / cc.

<Examples 2 to 3, Comparative Example 1>
A heat storage body was produced according to the same procedure as in Example 1 except that the type of material used was changed as shown in Table 1.

<Evaluation>
The following evaluations were carried out on the heat storage bodies obtained in Examples and Comparative Examples.

(Measurement of porosity)
Using an X-ray CT device, the porosity of the heat storage body was calculated according to the method described above.
The porosity was analyzed by peeling off the release film and analyzing only the heat storage body portion with an X-ray CT apparatus.

(Measurement of heat absorption)
The heat absorption amount of the obtained heat storage body was calculated from the differential scanning calorimetry.
For the latent heat capacity of the heat storage body, the heat absorption amount of the heat storage body itself from which the release film was peeled off was measured.

(Evaluation of handleability)
The heat storage body was cut into 15 mm × 25 mm to prepare a measurement sample. When 1 cm on both sides of the long side of the measurement sample was grasped and stretched 0.5 cm along the long side of the measurement sample, the appearance of defects (cracks and chips) in the heat storage body was visually observed. .. Evaluation was made according to the following criteria. Practically, "0" or "1" is preferable.
The case where no defect occurred was set as "0", the case where cracks occurred very slightly was set as "1", and the case where cracks and chips occurred was set as "2".

In Table 1, the "solid content (%)" column in the "resin" column represents the solid content concentration (mass%) in each commercially available product described in the "type" column in the "resin" column.
The "Tg (° C.)" column in the "resin" column in Table 1 represents the glass transition temperature (° C.) of the resin in the commercially available product used.
The "breaking elongation" column in the "resin" column in Table 1 represents the breaking elongation (%) of the resin in the commercially available product used.
The "resin content (mass%)" column in Table 1 represents the resin content (mass%) with respect to the total mass of the heat storage body.
The "heat storage material content (mass%)" column in Table 1 represents the content (mass%) of the heat storage material with respect to the total mass of the heat storage body.

The Superflex E2000 shown in Table 1 is a commercially available product sold by Dai-ichi Kogyo Seiyaku Co., Ltd., and the resin contained in the Superflex E2000 is polyurethane.
The Superflex 300 shown in Table 1 is a commercially available product sold by Dai-ichi Kogyo Seiyaku Co., Ltd., and the resin contained in the Superflex 300 is polyurethane.
The Superflex E4800 shown in Table 1 is a commercially available product sold by Dai-ichi Kogyo Seiyaku Co., Ltd., and the resin contained in the Superflex E4800 is polyurethane.
The Kuraray Poval KL-318 shown in Table 1 is a commercially available product sold by Dai-ichi Kogyo Seiyaku Co., Ltd., and the resin contained in Kuraray Poval KL-318 is polyvinyl alcohol.

As shown in Table 1, it was confirmed that the heat storage material of the present invention exhibited a desired effect.
Above all, when the porosity was 5% by volume or less, it was confirmed that the handleability was more excellent.

Claims

A heat storage body containing a microcapsule containing a heat storage material and a resin.
The content of the heat storage material with respect to the total mass of the heat storage body is 65% by mass or more.
A heat storage body having a porosity of less than 10% by volume.
The heat storage body according to claim 1, wherein the content of the resin is 20% by mass or less with respect to the total mass of the heat storage body.
The heat storage body according to claim 1 or 2, wherein the elastic modulus of the resin is 15 MPa or less.
The heat storage body according to any one of claims 1 to 3, wherein the glass transition temperature of the resin is 50 ° C. or lower.
The heat storage body according to any one of claims 1 to 4, wherein the resin has a breaking elongation of 300% or more.
The heat storage body according to any one of claims 1 to 5, wherein the ratio of the thickness of the capsule wall of the microcapsules to the volume-based median diameter of the microcapsules is 0.0075 or less.
The heat storage body according to any one of claims 1 to 6, wherein the thickness of the capsule wall of the microcapsule is 0.20 μm or less.
The heat storage body according to any one of claims 1 to 7, wherein the deformation rate of the microcapsules is 35% or more.
The heat storage body according to any one of claims 1 to 8, wherein the capsule wall of the microcapsule and the resin have the same functional group.
The heat storage body according to any one of claims 1 to 9, wherein the resin contains at least one selected from the group consisting of polyurethane, polyurea, and polyurethane urea.
The heat storage according to any one of claims 1 to 10, wherein both the resin and the capsule wall of the microcapsules contain at least one selected from the group consisting of polyurethane, polyurea, and polyurethane urea. body.
The heat storage body according to any one of claims 1 to 11, wherein the porosity is 5% by volume or less.
The heat storage body according to any one of claims 1 to 12, which has a thickness of 0.5 mm or more.
The method for manufacturing a heat storage body according to any one of claims 1 to 13.
A method for producing a heat storage body, wherein the heat storage body is manufactured by using the composition for forming a heat storage body containing the microcapsules, the resin, and water.
The method for producing a heat storage body according to claim 14, wherein the resin in the heat storage body forming composition is in the form of particles.