JP2007238912A - Heat storage microcapsule and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat storage microcapsule having a higher heat storage capacity per a unit weight than those of conventional ones, being physically and chemically stable and excellent in heat resistance, and a method of manufacturing the same. <P>SOLUTION: The heat storage microcapsule having a high heat storage capacity per a unit weight, physically and chemically stable and excellent in heat resistance can be obtained by using a water soluble latent heat storage material which stores or releases heat by phase change as a core substance and covering the core substance with a composite capsule wall formed by a composite of an inorganic compound and an organic polymeric compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat storage microcapsule having a higher heat storage amount per unit weight than that of the prior art, physically and chemically stable and excellent in heat resistance, and a method for producing the same.

  As a heat exchange means between the heat storage material and the heat medium, direct contact is the most efficient method. However, since the heat storage material and the heat medium often interact physically and chemically, indirect contact is unavoidable.

  As a heat exchange means by this indirect contact, a method of encapsulating a heat storage material and exchanging heat with a heat medium via a capsule membrane can be mentioned. This method is very effective because the surface area per unit volume of the heat storage material is increased, and various attempts have been made to reduce the size of capsules in order to make heat transfer more effective.

  For example, an encapsulation method using a composite emulsion method (see Patent Document 1), a method of spraying a thermoplastic resin on the surface of the heat storage material particles (see Patent Document 2), and forming a thermoplastic resin in a liquid on the surface of the heat storage material particles Heat storage micro, such as a method (see Patent Document 3), a method of polymerizing and coating a monomer on the surface of heat storage material particles (see Patent Document 4), a method of producing a polyamide-coated microcapsule by an interfacial polycondensation reaction (see Patent Document 5), etc. A method for manufacturing a capsule is disclosed.

  In the microcapsules encapsulating the heat storage material disclosed in these patent documents (hereinafter referred to as heat storage microcapsules), polystyrene or polyacrylonitrile obtained by a method such as an interfacial polymerization method or an in-situ method is used as the capsule wall material. In addition to polyamide, polyacrylamide, ethyl cellulose, polyurethane, organic polymers such as aminoplast resins such as urea formalin resin and melamine formalin resin are used. Further, as the heat storage material, a latent heat storage material that stores or dissipates heat by phase change is used, and specifically, n-paraffin, iso-paraffin, fatty acid, higher alcohol, and the like are often used. The amount of heat (heat storage amount) that these substances can store heat is almost determined by the amount of latent heat of fusion (ΔH) of each substance, and is in the range of ΔH = 120 to 240 kJ / kg (see FIG. 16). Further, the point at which heat is absorbed and released by the phase change of these substances, that is, the melting point of the substances is in the region of approximately 100 ° C. or less (see FIG. 16).

  By the way, in the heat storage microcapsule, the capsule wall is required to be physically and chemically stable and to have robustness. In addition, even when the heat storage microcapsule is exposed to a phase change temperature of the heat storage material to be included or a high temperature environment higher than that, high heat resistance is required so that the capsule does not break.

In this regard, a urea formalin resin synthesized by an in-situ method capable of synthesizing a physically and chemically stable wall material as an encapsulated wall material using an aliphatic hydrocarbon compound as a heat storage material. And heat storage microcapsules using a melamine formalin resin film are disclosed (see Patent Document 6).
Japanese Patent Laid-Open No. 62-1452 JP-A 62-45680 Japanese Patent Laid-Open No. 62-149334 JP-A-62-2225241 Japanese Patent Laid-Open No. 2-258052 JP 2003-306672 A

  However, in each of the heat storage microcapsules disclosed in Patent Documents 1 to 6, the capsule wall material is composed only of an organic polymer such as polystyrene, polyethylene, polyamide, and melamine formalin resin. For this reason, even if it is the melamine formalin resin with the highest heat resistance, when the use environment temperature is higher than 150 ° C., the encapsulated heat storage material leaks and the heat storage performance deteriorates.

  For this reason, the conventional heat storage microcapsule has a restriction that it can be used only at an atmospheric temperature of 150 ° C. or lower. Such a heat resistance limit is determined by the heat resistance of an organic polymer such as melamine formalin resin (ISO75: deflection temperature under load, also known as heat distortion temperature).

  On the other hand, in heat storage utilization using an internal combustion engine or the like as a heat source, the atmospheric temperature is assumed to be 200 ° C. or higher. For this reason, conventional heat storage microcapsules cannot be used for heat storage using an internal combustion engine or the like as a heat source, and further improvement in heat resistance of the microcapsules is desired.

  Further, the basic performance required for the heat storage microcapsule is the heat storage performance as the name suggests. The heat storage performance is evaluated for superiority or inferiority using the amount of latent heat of fusion when the inclusion contained in the microcapsule undergoes a phase change as an index. Examples of means for improving the heat storage performance of the heat storage microcapsule include the following two means. The first means is a means for reducing the thickness of the capsule wall material that does not contribute to the phase change and increasing the ratio of the inclusions in the heat storage microcapsules per unit weight. The second means is a means for microencapsulating a substance having a large amount of latent heat of fusion.

  The first means is to reduce the amount of raw material constituting the capsule wall in the capsule wall synthesis process. Thereby, the capsule wall can be thinned, and the heat storage amount per unit weight of the heat storage microcapsule can be increased. However, with the thinning of the capsule wall, new problems such as leakage of inclusions, a decrease in fastness, and a decrease in heat resistance arise. In order to improve the fastness and heat resistance of the capsule wall material, strength enhancement and heat resistance are imparted to the capsule wall composed only of organic polymer with an inorganic substance, etc. It is necessary.

  As a second means, there may be mentioned microencapsulation of sugars, sugar alcohols, inorganic salts, inorganic salt hydrates and the like having a large latent heat of fusion. If this is possible, the heat storage amount per unit weight of the heat storage microcapsules can be increased. However, in the conventional heat storage microcapsule, water is used in the production process, and the microcapsule is synthesized at the interface between the aqueous phase and the oil phase. Therefore, it is indispensable that the capsule inclusion is insoluble in water. . For this reason, the conventional technique has a problem that it is difficult to microencapsulate a water-soluble heat storage material having a large amount of latent heat of fusion.

  Accordingly, the object of the present invention is to solve the problems in the first means and the second means, thereby greatly increasing the amount of heat stored per unit weight and the phase change temperature of the contained heat storage material or Even when the microcapsules are exposed to the above high temperature environment (specifically, the atmospheric temperature is 200 ° C. or higher), the heat resistance is high so that the capsule wall is physically and chemically stable and does not break. An object of the present invention is to provide a heat storage microcapsule having a property and a method for producing the same.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, a water-soluble latent heat storage material that stores or dissipates heat by phase change is used as a core substance, and this core substance is covered with a composite capsule wall formed by combining an inorganic compound and an organic polymer compound, It has been found that a heat storage microcapsule having a higher heat storage amount per unit weight than that of the prior art, physically and chemically stable and excellent in heat resistance can be obtained, and the present invention has been completed. More specifically, the present invention provides the following.

  (1) A heat storage microcapsule having a core material having heat storage properties and a capsule wall covering the core material, wherein the core material is a water-soluble latent heat storage material that stores or dissipates heat by phase change. The capsule wall is a heat storage microcapsule that is a composite capsule wall formed by combining an inorganic compound and an organic polymer compound.

  (2) The heat storage microcapsule according to (1), wherein the inorganic compound is one or a mixture of two or more selected from the group consisting of calcium silicate, magnesium silicate, zinc silicate, tin silicate, and iron silicate.

  (3) The heat storage microcapsule according to (1) or (2), wherein the organic polymer compound is an aramid resin.

  (4) The heat storage microcapsule according to any one of (1) to (3), wherein the latent heat storage material is at least one selected from the group consisting of sugar, sugar alcohol, inorganic salt, and inorganic salt hydrate.

  In the heat storage microcapsule according to the present invention, a capsule wall covering a core material composed of a water-soluble latent heat storage material that stores or dissipates heat by phase change is formed by combining an inorganic compound and an organic polymer compound. It is a thing. That is, since a water-soluble heat storage material having a large amount of latent heat of fusion is microencapsulated, it has a higher heat storage amount per unit weight than in the past. In addition, the capsule wall is not only an organic polymer compound but also a composite material of an inorganic compound and an organic polymer compound, so that it is physically and chemically stable and robust, and has excellent heat resistance. Also has sex. Specifically, the heat storage microcapsule according to the present invention has heat resistance up to a use environment temperature of 250 ° C., and thus is effective for use of heat storage using an internal combustion engine or the like as a heat source.

  (5) A method for producing a heat storage microcapsule having a core material having heat storage properties and a capsule wall covering the core material, wherein the core material stores water-soluble latent heat for heat storage or heat dissipation by phase change. The latent heat storage material is added to an aqueous solution containing sodium silicate and aromatic diamine and mixed to form an aqueous phase, and an aromatic dicarboxylic acid chloride is added to the hydrocarbon solvent. Adding and mixing to form an oil phase, mixing the aqueous phase and the oil phase and stirring with heating to prepare a W / O dispersion, and the W / O dispersion By adding and mixing the system into an aqueous solution containing one or a mixture of two or more selected from the group consisting of calcium chloride, magnesium chloride, zinc chloride, tin chloride, and iron chloride, W / / W ′ dispersion and a capsule formed by combining the aramid resin and silicate, containing the latent heat storage material by heating and stirring the W / O / W ′ dispersion And a step of obtaining a wall.

  (6) A method for producing a heat storage microcapsule having a core material having a heat storage property and a capsule wall covering the core material, wherein the core material stores or heat-dissipates or dissipates heat by phase change. The latent heat storage material is added to an aqueous solution containing sodium silicate and aromatic diamine and mixed to form an aqueous phase, and an aromatic dicarboxylic acid chloride is added to the hydrocarbon solvent. Adding and mixing to form an oil phase; mixing the water phase and the oil phase and stirring with heating to prepare a W / O dispersion; and in a hydrocarbon solvent. By adding and mixing one or a mixture of two or more selected from the group consisting of calcium chloride, magnesium chloride, zinc chloride, tin chloride, and iron chloride, and C, A step of preparing an inorganic ion addition solution containing ions of Mg, Zn, Sn, and the like, and the W / O dispersion is added to the inorganic ion addition solution while stirring, and then heated and stirred. A process for producing a heat storage microcapsule comprising: encapsulating the latent heat storage material and obtaining a capsule wall formed by combining an aramid resin and a silicate.

  According to the method for producing a heat storage microcapsule according to the present invention, the capsule wall covering the core material composed of the water-soluble latent heat storage material is formed by combining an inorganic compound and an organic polymer compound. Microcapsules can be manufactured. Therefore, according to the production method of the present invention, it is possible to provide a heat storage microcapsule that has a higher heat storage amount per unit weight than the conventional one, is physically and chemically stable, and has excellent heat resistance.

  According to the heat storage microcapsule according to the present invention, it is possible to provide a heat storage microcapsule that has a higher heat storage amount per unit weight than conventional ones, is physically and chemically stable, and has excellent heat resistance.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

<Latent heat storage material>
The latent heat storage material constituting the core material of the heat storage microcapsule according to the present embodiment performs heat storage or heat dissipation using the latent heat accompanying the phase change. Specifically, a water-soluble latent heat storage material is used. For example, at least one selected from the group consisting of sugar, sugar alcohol, inorganic salt, and inorganic salt hydrate is preferably used.

  In particular, when the internal combustion engine or the like is used for heat storage using a heat source, the latent heat storage material preferably has a higher melting point, and specifically, a material having a melting point of 30 ° C. to 200 ° C. is preferable.

  Moreover, carbon, metal powder, alcohol, etc. may be added for the purpose of adjusting the thermal conductivity and specific gravity of the heat storage microcapsules and for the purpose of preventing overcooling.

<Capsule wall>
The capsule wall of the heat storage microcapsule according to this embodiment is formed by combining an inorganic compound and an organic polymer compound. As a preferable inorganic compound, silicates such as calcium silicate, magnesium silicate, zinc silicate, tin silicate, and iron silicate are used alone or in combination. For example, calcium silicate is synthesized by reacting sodium silicate (Na ₂ SiO ₃ ) with calcium chloride (CaCl ₂ ).

  As the organic polymer compound, an aramid resin is preferably used. The aramid resin is synthesized by reacting an aromatic diamine and an aromatic dicarboxylic acid chloride. For example, an aramid resin is obtained by reacting p-phenylenediamine (PPDA), which is an aromatic diamine, and isophthaloyl dichloride (IPDC), which is an aromatic dicarboxylic acid chloride.

<Method for producing thermal storage microcapsules>
[Production Example 1]
An example of the manufacturing method of the thermal storage microcapsule which concerns on this embodiment is demonstrated along the flow shown in FIG. In this manufacturing method, calcium silicate is used as the inorganic compound, an aramid resin is used as the organic polymer compound, and xylitol is used as the latent heat storage material constituting the core material. Moreover, sodium silicate and calcium chloride are used as the raw material for calcium silicate, and p-phenylenediamine (PPDA) and isophthaloyl dichloride (IPDC) are used as the raw material for the aramid resin.

[Step (1)]
First, an aqueous solution containing xylitol and p-phenylenediamine is added and mixed in an aqueous sodium silicate solution to prepare an aqueous phase. In parallel with this, isophthaloyl dichloride is added and mixed in a hydrocarbon solvent such as kerosene to produce an oil phase. Subsequently, after mixing these water phase and oil phase, it heat-stirs with stirring machines, such as a homogenizer, produces | generates microparticles | fine-particles, and the W / O dispersion system 10 is prepared. A schematic diagram of the W / O dispersion 10 prepared by this step (1) is shown in FIG.

  In addition, when producing an oil phase in the step (1), a dispersant such as sorbitan monooleate such as “Span 80” manufactured by Wako Pure Chemical Industries, Ltd. may be added and dispersed stably. preferable. The particle size is not particularly limited, but is preferably 10 μm to 20 μm, and the particle size can be controlled by changing the stirring conditions such as a homogenizer. Moreover, the heating temperature at the time of preparing the W / O dispersion system 10 is appropriately set according to the type of the latent heat storage material used as the core material.

[Step (2)]
The W / O dispersion 10 obtained in step (1) is added to and mixed with an aqueous calcium chloride solution, and then stirred at room temperature with an impeller to adjust the W / O / W ′ dispersion 20. When adjusting the W / O / W ′ dispersion, it is preferable to add a dispersion stabilizer such as sodium dodecylbenzenesulfonate (DBS) or polyvinyl alcohol (PVA) together and disperse stably. . A schematic diagram of the W / O / W ′ dispersion 20 prepared by this step (2) is shown in FIG.

[Step (3)]
While the W / O / W ′ dispersion system 20 obtained in the step (2) is heated and stirred, the calcium silicate synthesis reaction and the aramid resin synthesis reaction at the interface are started and advanced. The state of the reaction at the interface at this time is schematically shown in FIGS. As shown in FIG. 4, calcium ions 11 contained in the aqueous phase react with sodium silicate 12 contained in the inner aqueous phase to synthesize calcium silicate 15 (see FIG. 5). Further, isophthaloyl dichloride 13 contained in the oil phase reacts with p-phenylenediamine 14 contained in the inner aqueous phase to form an aramid resin 16, and the calcium silicate 15 and the aramid resin 16 are combined. (See FIG. 6).

  In the step (2), the capsule wall composition, that is, the composite state of calcium silicate and aramid resin is adjusted by appropriately changing the timing at which the W / O dispersion 10 is added to the calcium chloride aqueous solution. Is also possible.

  Finally, by demulsifying and washing, a heat storage microcapsule having a capsule wall formed by coating xylitol fine particles and forming a composite of an aramid resin and calcium silicate is obtained.

[Production Example 2]
Another example of the method for manufacturing the heat storage microcapsule according to the present embodiment will be described along the flow shown in FIG. In this production method, as in Production Example 1, calcium silicate is used as the inorganic compound, an aramid resin is used as the organic polymer compound, and xylitol is used as the latent heat storage material constituting the core material. Moreover, sodium silicate and calcium chloride are used as the raw material for calcium silicate, and p-phenylenediamine (PPDA) and isophthaloyl dichloride (IPDC) are used as the raw material for the aramid resin.

[Step (1)]
The step (1) in this production example is the same as the step (1) in the above production example 1. First, an aqueous solution containing xylitol and p-phenylenediamine is added and mixed in the sodium silicate aqueous solution, Make an aqueous phase. In parallel with this, isophthaloyl dichloride is added and mixed in a hydrocarbon solvent such as kerosene to produce an oil phase. Subsequently, after mixing these water phase and oil phase, it heat-stirs with stirring machines, such as a homogenizer, produces | generates microparticles | fine-particles, and prepares a W / O dispersion system.

  In addition, when producing an oil phase in the step (1), as in the step (1) in the above Production Example 1, dispersion of sorbitan monooleate or the like represented by “Span 80” manufactured by Wako Pure Chemical Industries, Ltd. It is preferable to add an agent and disperse stably. The particle size is not particularly limited, but is preferably 10 μm to 20 μm, and the particle size can be controlled by changing the stirring conditions such as a homogenizer. Moreover, the heating temperature at the time of preparing the W / O dispersion is appropriately set depending on the type of the latent heat storage material used as the core material.

[Step (2)]
Separately from the step (1), a phosphate ester surfactant represented by di (2ethylhexyl) phosphate (D2EHPA) or an acidic monophosphonate monoester interface in a hydrocarbon solvent such as kerosene An activator and calcium chloride are added and mixed, and stirred at room temperature with an impeller to prepare a calcium ion added solution.

[Step (3)]
While stirring the calcium ion added solution obtained in the step (2) at room temperature with an impeller, the W / O dispersion obtained in the step (1) is added and mixed. The mixed solution is heated and stirred to start and advance the calcium silicate synthesis reaction and the aramid resin synthesis reaction at the interface. The state of the reaction at the interface at this time is schematically shown in FIGS. As shown in FIG. 8, calcium ions 11 contained in the oil phase react with sodium silicate 12 contained in the inner aqueous phase, and calcium silicate 15 is synthesized (see FIG. 9). Further, isophthaloyl dichloride 13 contained in the oil phase reacts with p-phenylenediamine 14 contained in the inner aqueous phase to form an aramid resin 16, and the calcium silicate 15 and the aramid resin 16 are combined. (See FIG. 10).

  In the step (3), the capsule wall composition, that is, the composite state of calcium silicate and aramid resin is adjusted by appropriately changing the timing at which the W / O dispersion is added to the calcium ion added solution. Is also possible.

  Finally, by demulsifying and washing, a heat storage microcapsule having a capsule wall formed by coating xylitol fine particles and forming a composite of an aramid resin and calcium silicate is obtained.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

<Example 1>
Thermal storage microcapsules were manufactured according to the flow shown in FIG. First, 30 g of xylitol (manufactured by Tokyo Kasei Co., Ltd.) and 10 g of PPDA (manufactured by Kanto Chemical Co., Ltd.) in 10 ml of 6 kmol / m ³ aqueous solution of Na ₂ SiO ₃ (sodium silicate: manufactured by Kanto Chemical Co., Ltd.) An aqueous phase was prepared by mixing all of the PPDA solution obtained by dissolving.

  To 80 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.), 2.0 g of IPDC (manufactured by Kanto Chemical Co., Ltd.) and 1.6 g of sorbitan monooleate (“Span 80” manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersant were added and mixed. And an oil phase was prepared.

  The prepared water phase and oil phase were mixed, and then stirred for 10 minutes at 5000 rpm at a liquid temperature of 70 ° C. with a homogenizer to prepare a W / O dispersion.

The prepared W / O dispersion system was PVA (manufactured by Kanto Chemical Co., Inc.) with respect to 2.03 g of CaCl ₂ (manufactured by Kanto Chemical Co., Ltd.), 0.5 g of DBS (manufactured by Kanto Chemical Co., Ltd.) as a dispersion stabilizer, and 250 ml of pure water. ) The PVA aqueous solution obtained by dissolving 1.25 g was poured into 250 ml of distilled water in which 1.25 g was dissolved. Next, stirring was performed at 500 rpm at room temperature for 2 hours with an impeller to prepare a W / O / W ′ dispersion.

  The prepared W / O / W ′ dispersion was agitated at 400 rpm at 60 ° C. for 24 hours while starting an interfacial reaction to synthesize a calcium silicate wall and a polyaramid wall.

  Finally, demulsification and washing were performed to obtain heat storage microcapsules.

<Example 2>
Thermal storage microcapsules were manufactured according to the flow shown in FIG. First, 30 g of xylitol (manufactured by Tokyo Kasei Co., Ltd.) and 10 g of PPDA (manufactured by Kanto Chemical Co., Ltd.) in 30 ml of xylitol (manufactured by Tokyo Chemical Industry Co., Ltd.) in 10 ml of 6 kmol / m ³ aqueous solution of Na ₂ SiO ₃ (sodium silicate: manufactured by Kanto Chemical Co., Ltd.) An aqueous phase was prepared by mixing all of the PPDA solution obtained by dissolving the.

  Mix 80 kg of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.) with 2.0 g of IPDC (manufactured by Kanto Chemical Co., Ltd.) and 1.6 g of sorbitan monooleate (“Span 80” manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersant. Was made.

  The prepared water phase and oil phase were mixed, and then stirred for 10 minutes at 5000 rpm at a liquid temperature of 70 ° C. with a homogenizer to prepare a W / O dispersion.

Separately, 16.2 g of D2EHPA (manufactured by Kanto Chemical Co., Inc.) and 200 ml of ₂ kmol / m ³ aqueous solution of CaCl ₂ (manufactured by Kanto Chemical Co., Ltd.) were added and mixed in 200 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.). Next, the mixture was stirred with an impeller at room temperature at 400 rpm for 24 hours to prepare a calcium ion added solution.

  While stirring the prepared calcium ion-added solution at 400 rpm at room temperature with an impeller, the W / O dispersion prepared above was added and mixed. This mixed solution was stirred at 400 rpm at 60 ° C. for 24 hours to initiate and advance the interfacial reaction, thereby synthesizing a calcium silicate wall and a polyaramid wall.

  Finally, demulsification and washing were performed to obtain heat storage microcapsules.

<Comparative example>
As a comparative example, a heat storage microcapsule was manufactured according to the manufacturing method described in JP-A-2003-306672. First, 12 parts by mass of melamine powder (melamine “25093-02” (2,4,6-triamino-1,3,5-triazine) manufactured by Kanto Chemical Co., Inc.), 15.4 parts by mass of 37% formaldehyde aqueous solution and 40 of water. After adding a mass part and adjusting pH to 8, it heated to about 70 degreeC and obtained the melamine-formaldehyde initial condensate aqueous solution.

  Subsequently, n-octadecane (melting heat ΔH = 240 kJ / kg, melting point 30 to 32 ° C.) as a heat storage material in 100 parts by mass of a sodium salt aqueous solution of 10% styrene-maleic anhydride copolymer adjusted to pH 4.5. ) 80 parts by mass were added with vigorous stirring and emulsification was carried out until the particle size became 3.0 μm.

  The total amount of the above melamine-formaldehyde initial condensate aqueous solution is added to the obtained emulsion and stirred for 2 hours at 70 ° C., then the pH is raised to 9 and water is added, and the heat storage microcapsule dispersion with a dry solid content concentration of 40% is added. A liquid was obtained.

  Finally, it was demulsified and washed to obtain heat storage microcapsules.

<Enlarged observation>
About the thermal storage microcapsule obtained by Example 1, the enlarged photograph obtained as a result of carrying out the expansion observation by the scanning transmission electron microscope (acceleration voltage 200kV, 10kV) made from Hitachi is shown in FIG.11 and FIG.12. FIG. 11 is obtained by magnifying and observing the heat storage microcapsule from the surface. From FIG. 11, the heat storage microcapsule obtained in Example 1 has a shape close to a true sphere. confirmed. Moreover, FIG. 12 is obtained by magnifying and observing the cross section of the heat storage microcapsule. From FIG. 12, the heat storage microcapsule obtained in Example 1 is encapsulated with the inclusions included. It was confirmed that

<Cross-sectional composition analysis>
The thermal storage microcapsule obtained in Example 1 was cut using a Leica microtome equipped with a DiATOME knife to expose the cross section. Next, the cross section was observed using the electron microscope, and elemental analysis of the cross section was performed using an energy dispersive X-ray fluorescence analyzer (UTL EDS manufactured by Nolan, beam diameter: 1 nmφ). . Specifically, three element distribution analyzes of silicon, oxygen, and carbon were performed. The result is shown in FIG. As shown in FIG. 13, it was confirmed that the inclusion was mainly composed of carbon element, so that it was considered that xylitol was included. On the other hand, the capsule wall was mainly composed of silicon and oxygen, and a part of carbon was confirmed. Thus, it was considered that a capsule wall in which calcium silicate and aramid resin were combined was formed.

<Evaluation of heat resistance, melting point, heat of fusion>
The heat storage microcapsules obtained by Examples and Comparative Examples were evaluated for heat resistance, melting point, and heat of fusion.

<Heat resistance>
About each thermal storage microcapsule obtained by the Example and the comparative example, TG measurement of the thermal storage microcapsule was performed using a differential thermal thermogravimetric simultaneous measurement device (TG / DTA: EXSTAR6000-TG / DTA6200 manufactured by Seiko Instruments). . The TG curve obtained as a result is as shown in FIG. 14, and the onset temperature of weight reduction in this TG curve was used as an index for evaluating heat resistance.

  As shown in the TG curve of FIG. 14, in the comparative example, a weight reduction was observed at 150 to 200 ° C. On the other hand, in both Examples 1 and 2, it was found that weight reduction was observed at 250 to 300 ° C., and the starting temperature of weight reduction was shifted to the high temperature side by about 100 ° C. Thereby, it was confirmed that the heat storage microcapsule of a present Example has the heat resistance outstanding compared with the heat storage microcapsule of the comparative example.

<Melting point, heat of fusion>
About the thermal storage microcapsule obtained by the Example and the comparative example, the temperature of the endothermic peak and the exothermic peak was measured using the differential scanning calorimeter (DSC: Seiko Instruments Co., Ltd. SSC / 5520). The resulting DSC chart is shown in FIG.

  As shown in FIG. 15, in each of the heat storage microcapsules obtained in Examples 1 and 2, an endothermic peak due to the phase change of xylitol from solid to liquid was observed. That is, in the heat storage microcapsules of Examples 1 and 2, it was confirmed that the heat storage microcapsule has a function as a heat storage microcapsule by the peak due to the phase change of xylitol which is an included heat storage material. It was.

  Further, from the peak area values of the endothermic peaks in each of the examples and comparative examples, the heat storage amount of Example 1 is 169 kJ / kg, and the heat storage amount of Example 2 is 182 kJ / kg, whereas the heat storage amount of the comparative example is It was 145 kJ / kg. This difference in the amount of stored heat is mainly due to the difference in the latent heat of fusion of the core material contained therein. From these results, it was confirmed that any of the heat storage microcapsules produced by this example had a larger amount of heat storage per unit weight than the heat storage microcapsules produced by the comparative example.

It is a flowchart of the manufacture example 1 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 1 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 1 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 1 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 1 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 1 of the thermal storage microcapsule of embodiment. It is a flowchart of the manufacture example 2 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 2 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 2 of the thermal storage microcapsule of embodiment. It is drawing for demonstrating the manufacture example 2 of the thermal storage microcapsule of embodiment. 2 is an enlarged photograph of the surface of the heat storage microcapsule of Example 1. FIG. 2 is a cross-sectional enlarged photograph of a heat storage microcapsule of Example 1. FIG. It is drawing which shows the cross-sectional composition analysis result of the thermal storage microcapsule of Example 1. FIG. It is a figure which shows the TG curve of an Example and a comparative example. It is a figure which shows the DSC curve of an Example and a comparative example. It is a figure which shows the relationship between the kind of latent-heat storage material, and melting | fusing point-heat of fusion.

Explanation of symbols

1 W / O dispersion 2 W / O / W ′ dispersion 11 Calcium ions 12 Sodium silicate 13 Isophthaloyl dichloride 14 p-phenylenediamine 15 Calcium silicate 16 Aramid resin

Claims (6)

A heat storage microcapsule having a core material having a heat storage property and a capsule wall covering the core material,
The core material is a water-soluble latent heat storage material that stores or dissipates heat by phase change,
The capsule wall is a heat storage microcapsule that is a composite capsule wall formed by combining an inorganic compound and an organic polymer compound.   The heat storage microcapsule according to claim 1, wherein the inorganic compound is one or a mixture of two or more selected from the group consisting of calcium silicate, magnesium silicate, zinc silicate, tin silicate, and iron silicate.   The heat storage microcapsule according to claim 1 or 2, wherein the organic polymer compound is an aramid resin.   The heat storage microcapsule according to any one of claims 1 to 3, wherein the latent heat storage material is at least one selected from the group consisting of sugar, sugar alcohol, inorganic salt, and inorganic salt hydrate. A heat storage microcapsule manufacturing method comprising a core material having heat storage properties and a capsule wall covering the core material,
The core material is a water-soluble latent heat storage material that stores or dissipates heat by phase change, and this latent heat storage material is added to an aqueous solution containing sodium silicate and aromatic diamine to form an aqueous phase. And a process of
Forming an oil phase by adding and mixing an aromatic dicarboxylic acid chloride in a hydrocarbon solvent; and
A step of preparing a W / O dispersion by mixing the water phase and the oil phase and stirring with heating;
By adding and mixing the W / O dispersion in an aqueous solution containing one or a mixture of two or more selected from the group consisting of calcium chloride, magnesium chloride, zinc chloride, tin chloride, and iron chloride. Adjusting the W / O / W ′ dispersion;
Heat-stirring the W / O / W ′ dispersion to obtain a capsule wall containing the latent heat storage material and forming a capsule wall formed by combining an aramid resin and a silicate. Manufacturing method. A heat storage microcapsule manufacturing method comprising a core material having heat storage properties and a capsule wall covering the core material,
The core material is a water-soluble latent heat storage material that stores or dissipates heat by phase change, and this latent heat storage material is added to an aqueous solution containing sodium silicate and aromatic diamine to form an aqueous phase. And a process of
Forming an oil phase by adding and mixing an aromatic dicarboxylic acid chloride in a hydrocarbon solvent; and
A step of preparing a W / O dispersion by mixing the water phase and the oil phase and stirring with heating;
In a hydrocarbon solvent, by adding one or a mixture of two or more selected from the group consisting of calcium chloride, magnesium chloride, zinc chloride, tin chloride, and iron chloride, and a phosphate ester, and mixing them, Adjusting the inorganic ion added solution;
The W / O dispersion is added to the inorganic ion addition solution while stirring and mixed, and then heated and stirred to encapsulate the latent heat storage material and form a composite of aramid resin and silicate. A method for producing a heat storage microcapsule, comprising: obtaining a capsule wall.