JP2006257415A - Heat storage capsule and utilization thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat storage capsule which is tough in an extent not broken or difficultly broken, even when used as a heat transport medium, to provide a method for producing the same, to provide a heat transport medium using the same, and to provide a heat transport system. <P>SOLUTION: The heat storage capsule encapsulating a heat storage material in the hollow portion of a hollow capsule comprising a shell and the hollow portion is characterized in that the shell comprises a layer comprising a polymer or copolymer of at least one cross-linking monomer or a copolymer of at least one cross-linking monomer with at least one monofunctional monomer, and the polymer or copolymer contains the cross-linking monomer in an amount of 5 to 100 wt%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat storage medium used as a heat transport medium, a heat exchange medium for cooling and heating, a heat storage material for houses, a heat storage medium for preventing road freezing, a manufacturing method thereof, a heat transport medium, and a heat transport system.

  Water or the like is used as a heat transport medium for recovering waste heat from a factory zone or a garbage incineration plant and transporting it to a distant urban area where there is a great demand for heat. It has also been proposed to use a hydrogen storage alloy, methane or the like as a heat transport medium.

  It has also been proposed to use a material that stores and dissipates latent heat as a heat exchange medium with phase transition. Although this phase change material is a medium having high heat exchange performance, it cannot be used as a heat transport medium as it is because it is difficult to move when it becomes solid. For this reason, a heat storage material in which a phase change material is encapsulated has been proposed.

  For example, Patent Document 1 describes a heat storage microcapsule in which a heat storage material made of an aliphatic hydrocarbon compound such as hexadecane is housed in a capsule wall mainly composed of a thermoplastic resin. Since this microcapsule is a single-hole microcapsule, the heat storage material does not leak and the heat storage performance is maintained. According to this document, a non-crosslinkable resin or a resin having a crosslinkable resin component of 0.5% by weight or less is preferable as the thermoplastic resin constituting the capsule wall.

    Patent Document 2 discloses a heat storage microcapsule in which a heat storage material made of an aliphatic hydrocarbon compound is housed in a capsule wall mainly composed of a thermoplastic resin and has an average particle size of 10 to 3000 μm. Are listed. Although the literature does not define a preferred range of the ratio of the crosslinkable component to the non-crosslinkable component, in the examples, microcapsules in which the amount of the crosslinkable component used is 2% by weight are produced.

However, when the capsule wall is composed of a thermoplastic resin having a small amount of crosslinkable component, the strength of the obtained heat storage capsule is low. For this reason, when transporting or flowing in a metal pipe, such as a heat transport medium or a heat exchange medium for heating and cooling, the capsule wall is destroyed during use and the capsule wall is destroyed due to the collision between the capsule and the pipe wall. Performance is easily impaired and cannot be used for a long time. Therefore, it is limited to applications where there is no movement of the capsule, for example, a heat storage material used by being mixed with the road surface material to prevent road surface freezing.
JP 2004-203978 (Claim 1, paragraph 0028, etc.) JP 2001-247855 (Claim 1, paragraph 0029, etc.)

  It is an object of the present invention to provide a heat storage capsule that is tough to the extent that it is not broken or hardly broken even when used as a heat transport medium, a method for producing the capsule, a heat transport medium using the capsule, and a heat transport system. To do.

    In addition, the present invention provides a heat storage capsule in which a decrease in latent heat amount and supercooling, which are supposed to be generated by encapsulating a heat storage material, a manufacturing method thereof, a heat transport medium using the same, and a heat transport system are provided. Providing is also an issue.

The inventors of the present invention have made researches to solve the above problems, and have obtained the following knowledge.
(i) In a heat storage capsule in which a heat storage material is encapsulated in a hollow part of a hollow capsule composed of a shell and a hollow part, the shell is made of a polymer or copolymer of a crosslinkable monomer, or a crosslinkable monomer and a monofunctional monomer. Toughness sufficient to withstand transportation or flow by including a layer composed of a copolymer of 5 to 100% by weight of the crosslinkable monomer component in the polymer or copolymer. And a heat storage capsule that can be suitably used as a heat transport medium.
(ii) When the shell is composed of a copolymer of a crosslinkable monomer and a monofunctional monomer, and an ester of (meth) acrylic acid and an alcohol having 1 to 4 carbon atoms is used as the monofunctional monomer, The amount of latent heat per weight of the heat storage material is high, and the capsule has high heat storage efficiency. That is, the phenomenon of lowering the amount of latent heat caused by encapsulating the heat storage material is avoided.
(iii) Further, when the average particle size of the fine particles is set to 0.5 to 30 μm, an efficient capsule in which the supercooling phenomenon that supercooling is required when phase transition of the heat storage material from liquid to solid is suppressed is obtained.

  The present invention has been completed based on the above findings, and provides the following heat storage capsule, a manufacturing method thereof, a heat transport medium using the same, and a heat transport system.

    Item 1. A heat storage capsule in which a heat storage material is encapsulated in a hollow portion of a hollow capsule comprising a shell and a hollow portion, wherein the shell is a polymer of a crosslinkable monomer, a copolymer of two or more crosslinkable monomers, or at least one type A heat storage capsule comprising a layer composed of a copolymer of a crosslinkable monomer and at least one monofunctional monomer, wherein the polymer or copolymer contains 5 to 100% by weight of a crosslinkable monomer component.

    Item 2. Item 2. The heat storage capsule particle according to Item 1, wherein the average particle size is 0.05 to 50 µm.

    Item 3. Item 3. The heat storage capsule according to Item 1 or 2, wherein the shell includes a layer composed of a copolymer of at least one crosslinkable monomer and at least one monofunctional monomer.

    Item 4. Item 4. The heat storage capsule according to Item 3, wherein the ratio of the crosslinkable monomer in the polymer is 5 to 95% by weight.

    Item 5. Item 5. The heat storage capsule according to Item 3 or 4, wherein the monofunctional monomer is an ester of acrylic acid or methacrylic acid and an alcohol having 1 to 4 carbon atoms.

    Item 6. Item 6. The heat storage capsule according to any one of Items 1 to 5, wherein the heat storage material is a chain saturated hydrocarbon compound having 14 to 20 carbon atoms.

    Item 7. Item 7. The heat storage capsule according to any one of Items 1 to 6, comprising 10 to 80% by weight of the heat storage material with respect to the total amount of the heat storage capsule.

Item 8. In an aqueous dispersion stabilizer solution,
(I) heat storage material,
(Ii) a monomer component containing 5 to 100% by weight of at least one crosslinkable monomer and 0 to 95% by weight of at least one monofunctional monomer;
(Iii) Low compatibility with the polymer (PA) obtained by polymerizing or copolymerizing the monomer component, and the interfacial tension (γ ^x ) (mN / m) between the auxiliary polymer and water and the polymer In the relationship with the interfacial tension (γ ^y ) (mN / m) between (PA) and water, a mixture of auxiliary polymer (iv) initiator satisfying the condition of γ ^x ≧ γ ^y is dispersed, and suspension polymerization is performed. The manufacturing method of the thermal storage capsule including the process of reacting.

    Item 9. Item 9. The production method according to Item 8, wherein the heat storage material is a chain saturated hydrocarbon compound having 14 to 20 carbon atoms.

    Item 10. Item 10. The method according to Item 8 or 9, wherein the heat storage material is used in an amount of 10 to 80% by weight based on the total amount of the heat storage capsule.

    Item 11. Item 8. A heat transport medium comprising the heat storage capsule according to any one of Items 1 to 7.

    Item 12. A heat transport system that uses the heat storage capsule according to any one of Items 1 to 7 as a heat transport medium to absorb heat and dissipate heat at points distant from each other.

  The heat storage capsule of the present invention is excellent in strength and toughness because the ratio of the crosslinkable monomer component in the polymer or copolymer layer constituting the shell is as large as 5 to 100% by weight, and also when used as a heat transport medium. It has sufficient durability for practical use.

Hereinafter, the present invention will be described in detail.
(I) Thermal storage capsule In the thermal storage capsule of the present invention, a thermal storage material is encapsulated in a hollow portion of a hollow capsule composed of a shell and a hollow portion, and the shell is a polymer or copolymer of at least one crosslinkable monomer, or at least 1 The heat storage capsule includes a layer composed of a copolymer of a kind of crosslinkable monomer and at least one kind of monofunctional monomer, and the copolymer contains about 5 to 100% by weight of the crosslinkable monomer component.

    That is, the shell of the heat storage capsule of the present invention includes a layer obtained by polymerizing or copolymerizing a crosslinkable monomer or copolymerizing a polyfunctional monomer and a monofunctional monomer. Is used in an amount of about 5 to 100% by weight based on the total monomers. The layer of the polymer or copolymer of the shell has a substantially single layer structure. The shell may consist of only this layer or may have other layers.

    The ratio of the crosslinkable monomer component in the polymer or copolymer constituting the shell of the capsule of the present invention is preferably about 10 to 100% by weight, and more preferably 20 to 100% by weight. If the ratio of the crosslinkable monomer component is in the above range, it has sufficient strength and toughness, for example, when transporting or flowing inside the metal tube, it is difficult to be destroyed even by collision with each other or metal tube wall, It is not broken again. As a result, the heat storage performance is maintained for a long time.

    Further, when the shell is composed of a copolymer of a crosslinkable monomer and a monofunctional monomer, and an ester of acrylic acid or methacrylic acid and a lower alcohol having 1 to 4 carbon atoms is used as the monofunctional monomer, a heat storage material The amount of latent heat per weight increases and the capsule has good heat storage efficiency. Therefore, in the heat storage capsule of the present invention, when the above monofunctional monomer is used as the monomer constituting the shell, it is also preferable that the ratio of the crosslinkable monomer in the polymer is about 5 to 95% by weight. What is about 80 weight% is also more preferable.

    In general, when a heat storage material is encapsulated, a supercooling phenomenon that supercooling is required for phase transition to a solid tends to appear. This is described in, for example, Japanese Patent Application Laid-Open No. 05-237368.

  The average particle size of the heat storage capsule of the present invention is preferably about 0.05 to 50 μm, more preferably about 0.5 to 30 μm. Within this range, increasing the particle size did not significantly affect the amount of latent heat, but the degree of supercooling (the value obtained by subtracting the solidification temperature of the heat storage material in the capsule particles from the solidification temperature of the pure heat storage material) A tendency to become smaller was observed. Thereby, it comes to solidify at a higher temperature, and the energy at the time of solidifying the heat storage material can be reduced (see Table 4 below). It has been confirmed that capsules exceeding 50 μm are easily broken during the heat transport process. Thus, the thing in the range of said particle diameter is much more effective as a heat transport capsule.

    This particle diameter is an average value of particle diameters when 100 capsules are measured with an electron microscope or an optical microscope. When the average particle size is within the above range, the shell has an appropriate specific interfacial area and is easy to handle, and the shell wall has a sufficiently large relative thickness and is not easily destroyed. The average particle size can be adjusted by the method described later.

    Moreover, the volume ratio of the hollow part in the heat storage capsule of the present invention is preferably about 10 to 80%, particularly preferably about 10 to 60%. If it is the range of the volume ratio of the said hollow part, while the relative inclusion amount of a heat storage material and by extension, heat storage performance will become sufficient, a shell wall will become relatively thick and it will become difficult to destroy.

  Here, in the present specification, the “volume ratio of the hollow portion” R is calculated according to the following formula.

R (%) = (rh / rp) ³ × 100
(In the formula, rh is the radius of the hollow portion of the aromatic fine particles (1/2 of the inner diameter of the shell), and rp is the radius of the aromatic fine particles (1/2 of the outer diameter of the shell).)
The radius for calculating the volume ratio of the hollow portion is a value measured by an electron microscope or an optical microscope.
Thermal Storage Material In the present invention, the “thermal storage material” refers to a material that can store or dissipate latent heat with a phase change. Examples of such a heat storage material include, but are not limited to, a chain saturated hydrocarbon compound that is solid at room temperature, that is, a chain saturated hydrocarbon compound having 14 to 20 carbon atoms. Specifically, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, icosane, docosan and the like are preferable. Among these, hexadecane is more preferable because it has a melting point of 18 ° C. and can undergo phase transition near normal temperature.

About 10 to 80 weight% is preferable with respect to the whole quantity of a thermal storage capsule, and the amount of inclusion of the thermal storage material in the thermal storage capsule of this invention has more preferable about 10 to 60 weight%. If it is the range of said inclusion amount, while sufficient heat storage performance will be obtained, the relative thickness of a shell wall will become enough and it will become a thing which is hard to be destroyed. In the present specification, the ratio of the amount of the heat storage material encapsulated is easily obtained by calculation based on the charged weight ratio, but is a value obtained by thermogravimetric analysis.
The crosslinkable monomer The crosslinkable monomer is preferably hydrophobic, but this requirement is usually met.

As the crosslinkable monomer of the copolymer layer constituting the shell of the aromatic fine particles of the present invention, a polyfunctional monomer having two or more polymerizable reactive groups, particularly two or more polymerizable double bonds (particularly 2 to 4). Can be illustrated. In particular, a polyfunctional monomer having two or more polymerizable C═C double bonds (particularly 2 to 4) is preferable. For example, divinylbenzene, divinylbiphenyl, divinylnaphthalene, diallyl phthalate, triallyl cyanurate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate and the like can be mentioned. Particularly preferred are divinylbenzene and ethylene glycol dimethacrylate, and most preferred is ethylene glycol dimethacrylate. A polyfunctional monomer can be used individually or in mixture of 2 or more types.
Monofunctional monomer It is preferred that the monofunctional monomer is also hydrophobic, but this condition is usually met.

  Examples of monofunctional monomers include monovinyl aromatic monomers, (meth) acrylic monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, and halogenated olefin monomers. Examples thereof include dimers and diolefins.

  Examples of the monovinyl aromatic monomer include a monovinyl aromatic hydrocarbon represented by the following general formula (1), a vinylbiphenyl optionally substituted with a lower (1 to 4 carbon) alkyl group, and a lower (carbon number). 1-4) Vinyl naphthalene which may be substituted with an alkyl group.

［式中、Ｒ^１は、水素原子、低級（炭素数１〜４）アルキル基又はハロゲン原子であり、Ｒ^２は、水素原子、低級（炭素数１〜４）アルキル基、ハロゲン原子、−ＳＯ_３Ｎａ基、低級（炭素数１〜４）アルコキシ基、アミノ基又はカルボキシル基を示す。］
上記一般式（１）において、Ｒ^１は、水素原子、メチル基又は塩素原子が好ましく、Ｒ^２は、水素原子、塩素原子、メチル基又は−ＳＯ_３Ｎａ基であるのが好ましい。

[Wherein, R ¹ is a hydrogen atom, a lower (1 to 4 carbon atoms) alkyl group or a halogen atom, and R ² is a hydrogen atom, a lower (1 to 4 carbon atoms) alkyl group, a halogen atom, —SO 2 _{3 represents a} Na group, a lower (C1-4) alkoxy group, an amino group or a carboxyl group. ]
In the general formula (1), R ¹ is preferably a hydrogen atom, a methyl group or a chlorine atom, and R ² is preferably a hydrogen atom, a chlorine atom, a methyl group or a —SO ₃ Na group.

  Specific examples of the monovinyl aromatic hydrocarbon represented by the general formula (1) include styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, Examples include sodium styrene sulfonate.

  Furthermore, vinyl biphenyl which may be substituted with a lower alkyl group, and vinyl naphthalene which may be substituted with a lower alkyl group include lower (C1-4) alkyl groups such as vinyl biphenyl, methyl group and ethyl group. And vinyl naphthalene substituted with lower (1 to 4 carbon atoms) alkyl group such as vinyl biphenyl, vinyl naphthalene, methyl group, and ethyl group. These monovinyl aromatic monomers can be used alone or in combination of two or more.

  Moreover, as said (meth) acrylic-type monomer, the (meth) acrylic-type monomer represented by following General formula (2) is mentioned.

［式中、Ｒ^３は、水素原子又は低級（炭素数１〜４）アルキル基を示し、Ｒ^４は、水素原子、炭素数１〜１２のアルキル基、フェニル基、炭素数１〜６のヒドロキシアルキル基、低級（炭素数１〜４）アミノアルキル基又はジ（Ｃ_１-Ｃ_４アルキル）アミノ−（Ｃ_１-Ｃ_４）アルキル基を示す。］
一般式（２）において、Ｒ^３は、水素原子又はメチル基であるのが好ましく、Ｒ^４は、水素原子、炭素数１〜８のアルキル基、フェニル基、低級（炭素数１〜４）ヒドロキシアルキル基、低級（炭素数１〜４）ミノアルキル基が好ましい。

Wherein, ^{R 3} represents a hydrogen atom or a lower (1-4 carbon atoms) alkyl group, ^{R 4} is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a phenyl group, a hydroxy 1 to 6 carbon atoms An alkyl group, a lower (C 1-4) aminoalkyl group or a di (C ₁ -C ₄ alkyl) amino- (C ₁ -C ₄ ) alkyl group is shown. ]
In the general formula (2), R ³ is preferably a hydrogen atom or a methyl group, and R ⁴ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a phenyl group, or lower (1 to 4 carbon atoms) hydroxy. Alkyl groups and lower (C1-4) minoalkyl groups are preferred.

  Specific examples of the (meth) acrylic monomer include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, and methyl methacrylate. , Hexyl methacrylate, 2-ethylhexyl methacrylate, β-hydroxyethyl acrylate, γ-hydroxybutyl acrylate, δ-hydroxybutyl acrylate, β-hydroxyethyl methacrylate, γ-aminopropyl acrylate, γ-acrylate N, N-diethylaminopropyl and the like can be mentioned.

  Examples of the vinyl ester monomer include those represented by the following general formula (3).

［式中、Ｒ^５は水素原子又は低級（炭素数１〜４）アルキル基を示す。］
上記ビニルエステル系単量体の具体例としては、ギ酸ビニル、酢酸ビニル、プロピオン酸ビニル等が挙げられる。

[Wherein, R ⁵ represents a hydrogen atom or a lower (1 to 4 carbon atoms) alkyl group. ]
Specific examples of the vinyl ester monomer include vinyl formate, vinyl acetate, vinyl propionate and the like.

  Examples of the vinyl ether monomer include vinyl ether monomers represented by the following general formula (4).

［Ｒ^６は、炭素数１〜１２のアルキル基、フェニル基又はシクロヘキシル基を示す。］
上記ビニルエーテル系単量体の具体例としては、ビニルメチルエーテル、ビニルエチルエーテル、ビニルｎ−ブチルエーテル、ビニルフェニルエーテル、ビニルシクロヘキシルエーテル等が挙げられる。

[R ⁶ represents an alkyl group having 1 to 12 carbon atoms, a phenyl group, or a cyclohexyl group. ]
Specific examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl phenyl ether, vinyl cyclohexyl ether and the like.

  Examples of the monoolefin monomer include those represented by the following general formula (5).

［式中、Ｒ^７及びＲ^８は、水素原子又は低級（炭素数１〜４）アルキル基であり、それぞれ異なっていても同一でもよい。］
上記モノオレフィン系単量体の具体例としては、エチレン、プロピレン、ブテン−１、ペンテン−１、４−メチルペンテン−１等が挙げられる。

[In formula, R < ⁷ > and R < ⁸ > is a hydrogen atom or a lower (C1-C4) alkyl group, and may differ or may be the same respectively. ]
Specific examples of the monoolefin monomer include ethylene, propylene, butene-1, pentene-1, 4-methylpentene-1.

  Examples of the halogenated olefin monomer include vinyl chloride and vinylidene chloride.

  Furthermore, diolefins such as butadiene, isoprene and chloroprene can also be included in the monofunctional monomer. Monofunctional monomers can be used alone or in admixture of two or more.

The monofunctional monomer to be copolymerized with the crosslinkable monomer is preferably a monovinyl aromatic monomer, a (meth) acrylic monomer, a vinyl ester monomer, a vinyl ether monomer, or the like. Monomers and (meth) acrylic monomers are more preferred. Of the monovinyl aromatic monomers, styrene is preferred. Of the (meth) acrylic monomers, (meth) acrylic esters such as butyl acrylate, ethyl acrylate, and butyl methacrylate are preferred.
Combination of a crosslinkable monomer and a monofunctional monomer Even with a crosslinkable monomer alone, sufficient heat storage material inclusion particles can be obtained. As a suitable combination of a crosslinkable monomer and a monofunctional monomer, for example, the following Table 1 Combinations are listed.

（ＩＩ）蓄熱カプセルの製造方法
本発明の蓄熱カプセルは、種々の方法により製造することができるが、例えば以下の方法により製造することができる。

(II) Manufacturing method of heat storage capsule Although the heat storage capsule of this invention can be manufactured by various methods, it can be manufactured, for example with the following method.

That is, in an aqueous dispersion stabilizer solution,
(I) heat storage material,
(Ii) a monomer component containing 5 to 100% by weight of at least one crosslinkable monomer and 0 to 95% by weight of at least one monofunctional monomer;
(Iii) Low compatibility with the polymer (PA) obtained by polymerizing or copolymerizing the monomer component, and the interfacial tension (γ ^x ) (mN / m) between the auxiliary polymer and water and the polymer In the relationship with the interfacial tension (γ ^y ) (mN / m) between (PA) and water, the auxiliary polymer (iv) satisfying the condition of γ ^x ≧ γ ^y is dispersed and suspended. This is a method for conducting a polymerization reaction.
Dispersion stabilizers Dispersion stabilizers are used from a wide range that have the effect of preventing droplets formed by dispersing a mixture of heat storage materials, monomer components, auxiliary polymers and initiators in water. it can.

    For example, polymer dispersion stabilizers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, polyacrylic acid, polyacrylimide, polyethylene oxide, poly (hydroxystearic acid-g-methyl methacrylate-co-methacrylic acid) copolymer, nonion -Based surfactants, anionic surfactants, amphoteric surfactants and the like. Among these, polymer dispersion stabilizers such as polyvinyl alcohol are preferable.

  The amount of these dispersion stabilizers to be used can be selected from a wide range, but is generally about 0.005 to 1 part by weight, particularly about 1 part by weight of the mixture of the heat storage material, monomer component, auxiliary polymer and initiator. The amount is preferably about 0.01 to 0.1 parts by weight.

In addition, in the dispersion stabilizer aqueous solution, the concentration of the dispersion stabilizer may be appropriately selected so that the droplets do not coalesce. In general, the concentration of the aqueous dispersion stabilizer solution is preferably adjusted to about 0.05 to 5% by weight, particularly about 0.1 to 1% by weight.
The kind of heat storage material and the amount of heat storage material are as described above.

In addition, it is preferable to use a component that satisfies the following requirements 1) to 3) as the heat storage material. That is,
1) High compatibility with monomer components.
2) Low compatibility with a polymer (PA) obtained by polymerizing or copolymerizing monomer components.
3) and the surface tension between the heat storage material and water ^{(γ z) (mN / m} ), in relation to the interfacial tension ^{(γ y) (mN / m} ) between the polymer (PA) and water, gamma Satisfy the condition of ^z ≧ γ ^y .

  When using a heat storage material that satisfies the requirements of 1) to 3), an auxiliary polymer may be used, but it may not be used.

  The combination of the polymer (PA) satisfying the requirements of 1) to 3) and the heat storage material can be easily selected by the method described later. For example, it is a polyfunctional monomer such as divinylbenzene and a monofunctional monomer. Examples include a combination of a polymer obtained from styrene and hexadecane as a heat storage material.

  In the present specification, the compatibility between the heat storage material and the polymer (PA) is measured by the following method. That is, an initiator (2% by weight with respect to the monomer component) is added to a monomer component solution containing a monomer component that is a raw material of the polymer (PA), a heat storage material, and, if necessary, toluene in an appropriate weight ratio, The polymerization reaction of the monomer component is caused in a nitrogen gas atmosphere at 30 ° C. This reaction is carried out in a quartz glass cell having an optical path length of 1 cm, and the light transmittance is measured over time when irradiated with light having a wavelength of 550 nm. When the concentration of the heat storage material is increased, the transmittance, which was about 100% at the beginning, rapidly decreases to near 0% as the polymerization time elapses due to phase separation of the polymer (PA). In this case, if the compatibility between the heat storage material and the polymer (PA) is low, it decreases to nearly 0%, but if the compatibility between the heat storage material and the polymer (PA) is high, the transmittance hardly decreases. Further, the lower the compatibility between the heat storage material and the polymer (PA), the shorter the time from the start of polymerization until the decrease in transmittance occurs.

  As a heat storage material having low compatibility with the polymer (PA), when the transmittance is measured by the above method, the polymerization rate of the monomer component is about 1 to 10%, preferably about 1 to 5%. A heat storage material in which a decrease in the temperature occurs.

  In the present specification, the interfacial tension is a value measured by Dunui's platinum ring method as defined in ASTM-971-50.

  When using a heat storage material that satisfies the requirements of 1) to 3), the heat storage material is a phase of a monomer component and a polymer (PA) obtained by polymerizing or copolymerizing the monomer component without using an auxiliary polymer. Promote separation.

Even without using an auxiliary polymer, the monomer component is polymerized or copolymerized into a polymer (PA) in a uniform solution of the heat storage material, monomer component and initiator, and the polymer is adsorbed at the interface with water. In this case, the polymer (PA) is more easily adsorbed at the interface with water than the heat storage material, and as a result, fine particles in which the heat storage material is encapsulated inside the shell made of the polymer (PA) are obtained.
As the auxiliary polymer, polymers satisfying the following requirements 4) and 5) can be widely used. That is,
4) Low compatibility with a polymer (PA) obtained by polymerizing or copolymerizing monomer components.
5) in relation to the interfacial tension ^{(γ y) (mN / m} ) between the interfacial tension (gamma ^x) and (mN / m) and the polymer (PA) and water between the auxiliary polymer and water, gamma ^x The condition of ≧ γ ^y is satisfied.

  Specifically, as the auxiliary polymer, a polymer having a lower polarity than a polymer (PA) obtained by copolymerizing a crosslinkable monomer component and a monofunctional monomer can be used.

  In this specification, the compatibility between the auxiliary polymer and the polymer (PA) is measured using the auxiliary polymer in addition to the heat storage material in the method described for the compatibility between the heat storage material and the polymer (PA). .

    Examples of the auxiliary polymer having low compatibility with the polymer (PA) include auxiliary polymers in which the transmittance decreases when the polymerization rate of the monomer component is about 0.01 to 4%.

The interfacial tension is a value measured by Dunui's platinum ring method as defined in ASTM-971-50 as described above.
The auxiliary polymer is desirably dissolved in the monomer component, but this condition is usually satisfied.

The auxiliary polymer satisfying the requirements of 4) and 5) promotes phase separation between the monomer component and the polymer (PA) obtained by polymerization or copolymerization thereof.
Furthermore, in the mixture of the heat storage material, the monomer component, the auxiliary polymer and the initiator, the monomer component is copolymerized to become a polymer (PA), and the polymer (PA) is adsorbed at the interface with water. ) Is more easily adsorbed at the interface with water than the auxiliary polymer, and as a result, fine particles in which a heat storage material is encapsulated inside a shell made of polymer (PA) are obtained.

    As such an auxiliary polymer, for example, polystyrene, polymethyl methacrylate, polybutyl methacrylate and the like can be used.

  The combination of the monomer component and the auxiliary polymer that satisfies the requirements of 4) and 5) can be easily selected by the above-described method. For example, the combinations in Table 2 below can be exemplified.

補助ポリマーの使用量は、広い範囲から適宜選択できるが、一般には、モノマー成分１重量部に対して、０．０５〜０．４重量部程度、特に０．１〜０．２重量部程度とするのが好ましい。

The amount of the auxiliary polymer used can be appropriately selected from a wide range, but is generally about 0.05 to 0.4 parts by weight, particularly about 0.1 to 0.2 parts by weight with respect to 1 part by weight of the monomer component. It is preferable to do this.

The molecular weight of the auxiliary polymer can usually be about several hundred thousand.
Initiator The initiator used in the method of the present invention starts polymerization of the monomer component in the droplet, and oil-soluble polymerization initiators can be widely used. For example, azo compounds such as azobisisobutyronitrile which is a radical polymerization initiator, cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide, lauroyl peroxide, etc. Those soluble in monomers such as peroxides. Moreover, you may use the photoinitiator which starts superposition | polymerization by light, such as an ultraviolet-ray. Such a photopolymerization initiator is not particularly limited as long as it is oil-soluble, and includes those conventionally used.

The amount of the initiator used is preferably about 0.005 to 0.1 part by weight, particularly about 0.01 to 0.06 part by weight, based on 1 part by weight of the monomer component.
Dispersing Step In this method, a mixture containing the heat storage material, the monomer component, the initiator, and, if necessary, the auxiliary polymer in the above-mentioned use ratio is dispersed in an aqueous solution of the dispersion stabilizer, and suspension polymerization is performed.

    The heat storage material, the auxiliary polymer added as necessary, and the initiator are preferably dissolved in the monomer component to form a uniform solution. There is no limitation in particular as temperature at the time of mixing, For example, what is necessary is just to mix at about 0-30 degreeC.

  The mixture of the heat storage material, monomer component, initiator and auxiliary polymer added as necessary is then dispersed in an aqueous solution of the dispersion stabilizer.

  The mixture is preferably used in an amount of about 1 to 200 parts by weight, particularly about 10 to 100 parts by weight per 100 parts by weight of the aqueous dispersion stabilizer solution, but is not limited to this range. Absent.

  As the dispersion method, various known methods such as a dispersion method using mechanical shearing force such as a homogenizer or a membrane emulsification method can be employed. Although the temperature condition in the case of dispersion | distribution will not be limited if it is below the temperature which affects decomposition | disassembly of the heat storage material to be used and an initiator, It is preferable that it is about 0-30 degreeC.

  In the above dispersion method, the size of droplets formed by dispersing a uniform mixture of heat storage material, monomer component, initiator and possibly auxiliary polymer is not monodispersed, but generally droplets of various different particle sizes are mixed. Will be. Therefore, the finally obtained heat storage capsule also has a different particle size.

  On the other hand, by selecting a dispersion method, it is possible to make the size of the droplets uniform and obtain monodispersed droplets. As a method for obtaining such monodispersed droplets, for example, a method of producing monodispersed droplets by a membrane emulsification method using porous glass (SPG) or a seed swelling method (described in JP-A-8-20604). Method).

  When such monodispersed droplets having a uniform particle size are prepared, the finally obtained heat storage capsule is also monodispersed with a uniform particle size.

In any case, the average particle size of the droplets may be appropriately determined according to the desired average particle size of the heat storage capsule, but is generally about 0.05 to 50 μm, particularly about 0.1 to 20 μm. Is preferred. The viscosity of the mixture of the heat storage material, monomer component, initiator and auxiliary polymer added as necessary, the amount of dispersion stabilizer used, the viscosity of the dispersion stabilizer aqueous solution, the dispersion method / dispersion conditions should be appropriately set within the above ranges. As a result, a droplet average particle size in the above range is obtained.
Suspension polymerization In order to use in suspension polymerization an aqueous solution of a dispersion stabilizer in which a homogeneous mixture of the heat storage material, monomer component, initiator and auxiliary polymer added as necessary is dispersed, this aqueous solution is used. What is necessary is just to heat, stirring.

  The heating temperature is particularly limited as long as the monomer component is sufficiently polymerized by the initiator in the droplets of the homogeneous mixture of the heat storage material, monomer component, initiator and auxiliary polymer added as necessary. In general, however, the temperature is preferably about 30 to 90 ° C, particularly about 40 to 70 ° C.

  Suspension polymerization is performed until a desired heat storage capsule is obtained. The time required for suspension polymerization varies depending on the type of heat storage material, monomer component, and initiator used, but is generally about 3 to 48 hours.

  The suspension polymerization is preferably performed in an inert gas atmosphere such as nitrogen gas or argon gas.

  By performing suspension polymerization in this way, the monomer component is polymerized in droplets of a mixture of the heat storage material, monomer component, initiator and auxiliary polymer added as necessary.

  In the obtained monomer component copolymer (PA), phase separation is promoted by the presence of a heat storage material or further an auxiliary polymer, and as a result, a shell having a single layer structure, that is, a polymer (PA) is formed. Is done. On the other hand, the heat storage material and possibly an auxiliary polymer are included in the hollow portion.

  The heat storage material that is solid at room temperature is dissolved in the monomer component in the initial droplets of the reaction, but tends to precipitate as the copolymerization of the monomer component proceeds.

The heat storage capsule thus obtained may be used as it is in a dispersion, or after filtration and washing with water as necessary, it can be used in various forms in the form of powder. In the case of obtaining a heat storage capsule in the form of powder by drying the dispersion liquid, for example, at a temperature of about 0 to 50 ° C. and a pressure of about 10 ³ to 10 ⁵ Pa under temperature and pressure conditions where the heat storage material does not sublime or evaporate. Can be dried under conditions. The fine particles can also be dried by natural evaporation, reduced pressure treatment, or the use of a desiccant such as silica gel.

Thereby, the thermal storage capsule of this invention is obtained.
(III) Application Since the heat storage capsule of the present invention is excellent in toughness, it can be suitably used as a heat transport medium in a heat transport system. That is, the heat transport medium of the present invention includes the heat storage capsule described above. In addition to the heat storage capsule of the present invention, the heat transport medium may contain conventional materials such as water, an emulsifier, an aqueous salt solution, a solvent, and an antifreeze solution.

The heat transport system of the present invention uses a heat transport medium including the heat storage capsule of the present invention.
EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
<Method for measuring the amount of heat storage material included>
The obtained heat storage material capsules in an emulsion or slurry state are temperature range 50-300 ° C., temperature rising rate 5 ° C./min using differential thermothermal weight simultaneous measurement device (model EXSTAR6000 TG / DTA manufactured by Seiko Instruments Inc.). The weight loss with increasing temperature was measured. Since the encapsulated hexadecane evaporated in the range of 170 to 260 ° C., it was calculated from the weight loss in that range. The encapsulated amount of the heat storage material can be calculated and confirmed from the residual polymer weight and the polymerization rate after the measurement is completed.
<Evaluation of latent heat>
Using a differential scanning calorimeter (Model EXSTAR6000DSC, manufactured by Seiko Instruments Inc.), the heat-storing material-containing capsule particles in the emulsion state are reciprocated three times from minus 20 ° C. to 40 ° C. at a rate of 5 ° C./min. The melting point of the heat storage material was determined from the results of the temperature rise process, the freezing point of the heat storage material was determined from the second temperature drop process, and from the peak area value and the amount of heat storage material obtained from the above method used for measurement, hexadecane The amount of latent heat per unit weight and the amount of latent heat per capsule particle unit weight were determined.
<Toughness evaluation method>
The dried heat storage material capsule (including all or part of hexadecane) was measured with a micro indentation meter (manufactured by Shimadzu Corporation, dynamic ultra indentation hardness meter) using a flat indenter (diameter of 50 μm). Specifically, the dried capsule was set on the sample stage, and it was confirmed that there was only one capsule in the indenter range. A compression test was performed, and the load when it was broken was determined as the crush limit load. More than 30 measurements were made for each sample, and the average value was taken as toughness.
Example 1 (100% polyfunctional monomer, using styrene)
(A) An aqueous solution obtained by dissolving 500 mg of polyvinyl alcohol as a dispersion stabilizer (A) in 50 g of water, 4 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as a polyfunctional monomer (B), a heat storage material (C ) 4 g of hexadecane (manufactured by Nacalai Tesque) and 160 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as the polymerization initiator (D) were suspended. The ratio of polyfunctional monomer in the monomer is 100%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high speed mini kit) having a pore size of 1.1 μm as an apparatus under room temperature conditions.

  (B) The suspension was then heated at 70 ° C. and polymerized for 8 hours.

    When the obtained dispersion was observed with an optical microscope, a hollow structure was observed. The obtained fine particles had an average particle size of 9 μm and an average particle size variation coefficient of 14%.

    When the amount of hexadecane encapsulated in the obtained hexadecane capsule particles was subjected to a differential thermothermal gravimetric simultaneous measurement apparatus according to the above method, the weight ratio was hexadecane: polydivinylbenzene = 1: 1. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was 76 joules per gram of capsule particles. When converted per hexadecane, it is approximately 150 joules / g.

Among the obtained fine particles, the crushing limit load of 8 to 10 μm particles was 5 to 15 mN.
Example 2 (polyfunctional monomer 80% by weight, using styrene)
(A) In an aqueous solution obtained by dissolving 500 mg of polyvinyl alcohol as a dispersion stabilizer (A) in 50 g of water, 3.2 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as a polyfunctional monomer (B), monofunctional Uniform mixing of 0.8 g of styrene (manufactured by Mitsubishi Chemical) as the reactive monomer (E), 4 g of hexadecane (manufactured by Nacalai Tesque) as the heat storage material (C), and 160 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as the polymerization initiator (D) The resulting solution was suspended. The proportion of multifunctional monomer in the monomer is 80%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high speed mini kit) having a pore size of 1.1 μm as an apparatus under room temperature conditions.

  (B) The suspension was then heated at 70 ° C. and polymerized for 8 hours.

    When the obtained dispersion was observed with an optical microscope, a hollow structure was observed. The obtained fine particles had an average particle size of 10 μm.

    When the amount of hexadecane encapsulated in the obtained hexadecane capsule particles was subjected to a differential thermothermal gravimetric simultaneous measurement apparatus according to the above method, the weight ratio was hexadecane: divinylbenzene-styrene copolymer = 1: 1. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was 70 joules per gram of capsule particles.

Among the obtained fine particles, 9 to 11 μm particles had a crushing limit load of 3 to 10 mN.
Example 3 (12.5% by weight of polyfunctional monomer, using styrene)
(A) In an aqueous solution obtained by dissolving 500 mg of polyvinyl alcohol as a dispersion stabilizer (A) in 50 g of water, 0.5 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as a polyfunctional monomer (B), monofunctional Uniform mixing of 3.5 g of styrene (manufactured by Mitsubishi Chemical) as the reactive monomer (E), 4 g of hexadecane (manufactured by Nacalai Tesque) as the heat storage material (C), and 160 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as the polymerization initiator (D) The resulting solution was suspended. The proportion of multifunctional monomer in the monomer is 12.5%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high speed mini kit) having a pore size of 1.1 μm as an apparatus under room temperature conditions.

(B) The suspension was then heated at 70 ° C. and polymerized for 8 hours.
When the obtained dispersion was observed with an optical microscope, a hollow structure was observed. The obtained fine particles had an average particle size of 10 μm.

    When the amount of hexadecane encapsulated in the obtained hexadecane capsule particles was subjected to a differential thermothermal gravimetric simultaneous measurement apparatus according to the above method, the weight ratio was hexadecane: divinylbenzene-styrene copolymer = 1: 1. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was about 70 joules per gram of capsule particles.

Among the obtained fine particles, 9-11 μm particles had a crushing limit load of 2 to 7 mN.
Comparative Example 1 (3.7% by weight of polyfunctional monomer, using styrene)
(A) 0.15 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as monofunctional monomer (B) in an aqueous solution obtained by dissolving 500 mg of polyvinyl alcohol in 50 g of water as a dispersion stabilizer (A), monofunctional 3.85 g of styrene (manufactured by Mitsubishi Chemical) as the reactive monomer (E), 4 g of hexadecane (manufactured by Nacalai Tesque) as the heat storage material (C), and 160 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as the polymerization initiator (D) The resulting solution was suspended. The proportion of multifunctional monomer in the monomer is about 3.8%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high speed mini kit) having a pore size of 1.1 μm as an apparatus under room temperature conditions.

  (B) The suspension was then heated at 70 ° C. and polymerized for 8 hours.

    When the obtained dispersion was observed with an optical microscope, a hollow structure was observed. The obtained fine particles had an average particle diameter of 11 μm.

    When the amount of hexadecane encapsulated in the obtained hexadecane capsule particles was subjected to a differential thermothermal gravimetric simultaneous measurement apparatus according to the above method, the weight ratio was hexadecane: divinylbenzene-styrene copolymer = 1: 1. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was about 65 Joules per gram of capsule particles.

Among the obtained fine particles, the crushing limit load of 10 to 12 μm particles was 1 mN or less. Such fine particles with low toughness are easily broken and difficult to put into practical use when used as a heat transport medium.

The following shear strength tests 1 and 2 were conducted in order to confirm that the heat storage capsules obtained in each of the following examples were suitable as a heat transport medium.
<Shear strength test 1 of heat storage material>
The obtained heat storage material capsules were subjected to a shearing force for 8 minutes at room temperature at a speed of 2500 rpm with a biomixer (Model ABM-2 manufactured by Nippon Seiki Seisakusho) in an emulsion state of 10% solid content (including paraffin). After stirring with a biomixer, the morphology of the particles was confirmed by observation with an optical microscope. Furthermore, if the emulsion is broken, the encapsulated hexadecane elutes to the outside, and in order to observe it, the emulsion after stirring was treated with a centrifuge at 15000 rpm for 10 minutes, It was judged with the naked eye whether it appeared in the upper layer.

<Shear strength test 2 of heat storage material>
The obtained heat storage material capsule was circulated in an emulsion state of 200% solid content (including paraffin) at a rate of 10 liters / minute at room temperature with a magnet pump (model MD-15FY, manufactured by Iwaki Co., Ltd.) for 24 hours. . After circulation, the morphology of the particles was confirmed by observation with an optical microscope. Furthermore, since the encapsulated hexadecane elutes to the outside if the emulsion is broken, the emulsion after stirring is treated at 15000 rpm for 10 minutes in a centrifuge to observe it, The weight of the amount of paraffin that appeared was measured.

Example 6 (use of 100% polyfunctional monomer)
(A) In an aqueous solution obtained by dissolving 1 g of polyvinyl alcohol in 100 g of water as a dispersion stabilizer (A), 5 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as a polyfunctional monomer (B), a heat storage material (C ) 5 g of hexadecane (manufactured by Nacalai Tesque) and 120 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as the polymerization initiator (D) were suspended. The ratio of polyfunctional monomer in the monomer is 100%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high-speed mini kit) having a pore size of 1.3 μm as an apparatus at room temperature.

  (B) The suspension was then heated at 70 ° C. and polymerized for 24 hours.

    When the obtained dispersion was observed with an optical microscope, a hollow structure was observed. The obtained fine particles had an average particle size of 10 μm and an average particle size variation coefficient of 14%.

    It was confirmed with an optical microscope that all the obtained particles encapsulated hexadecane.

The above test 1 and test 2 were performed on the capsules thus obtained.
(Test 1) After the homogenizer treatment, when observed with an optical microscope, all the particles were not different from the pretreatment. When the emulsion was further centrifuged, the specific gravity decreased because the capsule particles contained hexadecane, and the particles separated into the upper layer, but the entire system separated into two layers, the medium and the particle layer, and the hexadecane was eluted. Not observed.
(Test 2) When observed with an optical microscope after the magnet pump treatment, capsule destruction with a particle size of 20 μm or more contained in part was observed, but no breakage was observed for other particles of about 10 μm. After centrifugation, a slight hexadecane layer was observed, but the ratio was 10% or less of the total.

Comparative Example 2 (use of 4% polyfunctional monomer)
(A) 0.2 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as a polyfunctional monomer (B) in an aqueous solution obtained by dissolving 1 g of polyvinyl alcohol in 100 g of water as a dispersion stabilizer (A), monofunctional 4.8 g of styrene (manufactured by Mitsubishi Chemical) as the reactive monomer (E), 5 g of hexadecane (manufactured by Nacalai Tesque) as the heat storage material (C), and 120 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as the polymerization initiator (D) The resulting solution was suspended. The proportion of multifunctional monomer in the monomer is 4%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high-speed mini kit) having a pore size of 1.3 μm as an apparatus at room temperature.

  (B) The suspension was then heated at 70 ° C. and polymerized for 24 hours.

    When the obtained dispersion was observed with an optical microscope, a hollow structure was observed. The obtained fine particles had an average particle size of 10 μm.

    As for the obtained particles, particles encapsulating hexadecane were also observed, but about 50% of the particles already having dents due to the weak shell strength.

The above test 1 and test 2 were performed on the capsules thus obtained.
(Test 1) After the homogenizer treatment, when observed with an optical microscope, the shell layer was broken for all particles, and the capsule was observed to be broken. When the emulsion was centrifuged, the uppermost layer was a transparent hexadecane layer, the second layer was a particle-separated layer, the lowermost layer was separated into a medium and three layers, and hexadecane elution was observed.
(Test 2) After the magnet pump treatment, most of the main capsules having a particle size of about 10 μm were broken when observed with an optical microscope. In addition, the hexadecane layer was clearly observed after centrifugation, and the ratio was more than 50% of the total, but it was confirmed that paraffin remained in the broken capsule. It is presumed that the capsule was destroyed.
Example 7 (polyfunctional monomer 20% by weight, using butyl acrylate)
(A) 0.52 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as a polyfunctional monomer (B) in an aqueous solution obtained by dissolving 500 mg of polyvinyl alcohol in 50 g of water as a dispersion stabilizer (A), monofunctional Uniform mixing of 2.1 g of butyl acrylate (manufactured by Nacalai Tesque) as a reactive monomer, 4 g of hexadecane (manufactured by Nacalai Tesque) as a heat storage material (C), and 100 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as a polymerization initiator (D) The resulting solution was suspended. The proportion of multifunctional monomer in the monomer is 20%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high speed mini kit) having a pore size of 1.1 μm as an apparatus under room temperature conditions.

(B) The suspension was then heated at 70 ° C. and polymerized for 8 hours.
When the obtained dispersion was observed with an optical microscope, particles that were dented due to the hollow structure were observed. The obtained fine particles had an average particle diameter of 11 μm and a coefficient of variation of the average particle diameter of 14%.

    When the apparatus for simultaneous differential thermothermal gravimetric measurement of the amount of hexadecane encapsulated in the obtained hexadecane capsule particles was performed according to the above method, the weight ratio was hexadecane: polymer = 6: 4. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was 136 joules per gram of capsule particles. When converted per hexadecane, it is approximately 227 joules / g.

Table 3 shows the results of capsule particles prepared under the same conditions as above except that the copolymer composition ratio of divinylbenzene and butyl acrylate was changed.

Comparative Example 3
Divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) 0.8 g as the polyfunctional monomer (B), 3.2 g of butyl acrylate (manufactured by Nacalai Tesque) as the monofunctional monomer, and hexadecane (Nacalai Tesque) as the heat storage material (C) (Product made) 4g and others produced capsule particles under the same conditions as in Example 7. As a result, porous particles were produced instead of capsule particles. The amount of latent heat measured with a differential scanning calorimeter in a water-dispersed state was 35 joules per gram of capsule particles. When converted per hexadecane, it is approximately 70 joules / g.

Comparative Example 4
Divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) 0.52 g is used as the polyfunctional monomer (B), and 2.1 g of methyl acrylate (manufactured by Nacalai Tesque) is used as the monofunctional monomer. When capsule particles were prepared, countless by-product fine particles were produced in addition to the capsule particles, and capsule particles having a composition ratio could not be produced.

Example 8 (use of polyfunctional monomer (35) wt%, (ethyl acrylate))
As polyfunctional monomer (B), divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) 0.9 g, and monofunctional monomer ethyl acrylate (manufactured by Nacalai Tesque) 1.7 g were used. When capsule particles were made with, similar dented particles were observed. The obtained fine particles had an average particle size of 8 μm and an average particle size variation coefficient of 13%. The amount of latent heat measured with a differential scanning calorimeter in a water-dispersed state was 138 joules per gram of capsule particles. When converted per hexadecane, it is 230 joules / g.

Table 4 shows the results of capsule particles prepared under the same conditions as above except that the copolymer composition ratio of divinylbenzene and butyl acrylate was changed.

Example 9 (Use of polyfunctional monomer 35% by weight, normal butyl methacrylate)
As the polyfunctional monomer (B), 0.9 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) and 1.7 g of normal butyl methacrylate (manufactured by Nacalai Tesque) as the monofunctional monomer were used. When capsule particles were prepared under the same conditions, similar indented particles were observed. The obtained fine particles had an average particle size of 9 μm and a coefficient of variation of the average particle size of 16%. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was about 133 joules per gram of capsule particles. When converted per hexadecane, it is approximately 222 joules / g.

Table 5 shows the results of capsule particles prepared under the same conditions as above except that the copolymer composition ratio of divinylbenzene and butyl acrylate was changed.

Example 10 (use of polyfunctional monomer 50% by weight, isobutyl methacrylate)
As polyfunctional monomer (B), 1.3 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) and 1.3 g of isobutyl methacrylate (manufactured by Nacalai Tesque) were used as the monofunctional monomer. When capsule particles were made with, similar dented particles were observed. The obtained fine particles had an average particle size of 8 μm and an average particle size variation coefficient of 16%. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was about 113 joules per gram of capsule particles. When converted per hexadecane, it is about 188 joules / g.

Example 11 (100% by weight of multifunctional monomer; average particle size 25 μm)
(A) An aqueous solution obtained by dissolving 500 mg of polyvinyl alcohol as a dispersion stabilizer (A) in 50 g of water, 4 g of divinylbenzene (manufactured by Nippon Steel Chemical Co., Ltd., DVB96) as a polyfunctional monomer (B), a heat storage material (C ) 4 g of hexadecane (manufactured by Nacalai Tesque) and 160 mg of benzoyl peroxide (manufactured by Nacalai Tesque) as the polymerization initiator (D) were suspended. The proportion of multifunctional monomer in the monomer is 20%.

  The suspension was carried out using a membrane emulsification apparatus (SPG Techno high-speed mini kit) having a pore size of 4.9 μm as an apparatus at room temperature.

(B) The suspension was then heated at 70 ° C. and polymerized for 8 hours.
When the obtained dispersion was observed with an optical microscope, particles having a hollow structure were observed. The obtained fine particles had an average particle diameter of 25 μm and an average particle diameter variation coefficient of 8%.

    When the differential thermal thermogravimetric simultaneous measurement apparatus of the hexadecane inclusion amount of the obtained hexadecane capsule particle | grains was carried out according to the said method, it was hexadecane: polymer = 1: 1 by weight ratio. When the amount of latent heat was measured in a water-dispersed state with a differential scanning calorimeter, it was 72 joules per gram of capsule particles. When converted per hexadecane, it is 143 joules / g. When the SPG membrane pore diameter used was changed during suspension, the results shown in Table 6 were obtained. Although the amount of latent heat remained almost unchanged, the degree of supercooling (freezing point of pure hexadecane minus the freezing point of hexadecane in capsule particles) improved as the particle size increased.

Claims (12)

A heat storage capsule in which a heat storage material is encapsulated in a hollow portion of a hollow capsule comprising a shell and a hollow portion, wherein the shell is a polymer of a crosslinkable monomer, a copolymer of two or more crosslinkable monomers, or at least one type A heat storage capsule comprising a layer composed of a copolymer of a crosslinkable monomer and at least one monofunctional monomer, wherein the polymer or copolymer contains 5 to 100% by weight of a crosslinkable monomer component. The heat storage capsule particle according to claim 1, wherein the average particle diameter is 0.05 to 50 µm. The heat storage capsule according to claim 1 or 2, wherein the shell includes a layer composed of a copolymer of at least one crosslinkable monomer and at least one monofunctional monomer. The heat storage capsule according to claim 3, wherein the proportion of the crosslinkable monomer in the polymer is 5 to 95% by weight. The heat storage capsule according to claim 3 or 4, wherein the monofunctional monomer is an ester of acrylic acid or methacrylic acid and an alcohol having 1 to 4 carbon atoms. The heat storage capsule according to any one of claims 1 to 5, wherein the heat storage material is a chain saturated hydrocarbon compound having 14 to 20 carbon atoms. The heat storage capsule according to any one of claims 1 to 6, comprising 10 to 80% by weight of the heat storage material with respect to the total amount of the heat storage capsule. In an aqueous dispersion stabilizer solution,
(I) heat storage material,
(Ii) a monomer component containing 5 to 100% by weight of at least one crosslinkable monomer and 0 to 95% by weight of at least one monofunctional monomer;
(Iii) Low compatibility with the polymer (PA) obtained by polymerizing or copolymerizing the monomer component, and the interfacial tension (γ ^x ) (mN / m) between the auxiliary polymer and water and the polymer In the relationship with the interfacial tension (γ ^y ) (mN / m) between (PA) and water, a mixture of auxiliary polymer (iv) initiator satisfying the condition of γ ^x ≧ γ ^y is dispersed, and suspension polymerization is performed. The manufacturing method of the thermal storage capsule including the process of reacting. The manufacturing method according to claim 8, wherein the heat storage material is a chain saturated hydrocarbon compound having 14 to 20 carbon atoms. The method according to claim 8 or 9, wherein the heat storage material is used in an amount of 10 to 80% by weight based on the total amount of the heat storage capsule. The heat transport medium containing the heat storage capsule in any one of Claims 1-7. A heat transport system that uses the heat storage capsule according to any one of claims 1 to 7 as a heat transport medium to absorb heat and dissipate heat at points distant from each other.