JP2007145915A - Thermal storage gel, method for producing the same and thermal storage material using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide thermal storage gel having excellent moldability, weather resistance and moisture resistance and widely regulating hardness without especially causing bleed of an oil, etc., to provide a method for producing the same and to provide a thermal storage material using the same. <P>SOLUTION: The thermal storage gel is characterized as comprising 90-10 vol.% of silicone gel and 10-90 vol.% of a microcapsule containing a latent heat thermal storage agent having preferably 0-80°C melting point in a shell. The penetration specified by JIS K2207-1980 (50 g load) is preferably 30-250. The method for producing the same is provided and the thermal storage material comprises the gel sealed in an encapsulating material, etc. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat storage gel, a method for producing the same, and a heat storage material using the same, and more specifically, a heat storage gel comprising a silicone gel and a microcapsule containing a latent heat storage agent, a method for producing the same, and a heat storage using the same. Regarding materials.

Conventionally, as a heat storage material that keeps an object in a cooled or warmed state, particularly a familiar heat storage material, it is possible to store and release a large amount of heat in a narrow temperature range by using latent heat accompanying phase transition. A heat storage material in which water, an aliphatic hydrocarbon compound, or the like, which is a compound, is contained in a microcapsule is known. Use of these heat storage materials for building materials, clothing, etc. is being studied.
For example, a heat storage material obtained by solidifying a microcapsule enclosing a compound having a phase change with a binder resin such as a styrene-butadiene copolymer (see, for example, Patent Document 1), a latent heat storage agent microencapsulated with water as a solvent A heat insulating material and a heat insulating material (see, for example, Patent Document 2) dispersed in a lipogel using hydrogel or oil as a solvent are disclosed. However, from these binder resins and gels, there was a risk that moisture and oil would ooze out, and there was a big problem in moldability due to large restrictions such as encapsulation during use to prevent oozing out of the heat storage material. .
JP-A-7-133479 JP 2005-255726 A

  In view of the above problems, an object of the present invention is a heat storage gel that is excellent in moldability, weather resistance, and moisture resistance, and that can be adjusted in a wide range of hardness without causing bleeding such as oil, and a method for producing the same. It is to provide the heat storage material.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have excellent moldability, weather resistance, and moisture resistance by including a microcapsule containing a latent heat storage agent in a specific amount of shell in a silicone gel. In particular, the present inventors have found that a heat-storing gel capable of adjusting the hardness in a wide range can be obtained without causing bleeding such as oil.

  That is, according to the first invention of the present invention, the heat storage gel characterized by containing 90 to 10% by volume of silicone gel and 10 to 90% by volume of microcapsules containing a latent heat storage agent in the shell. Is provided.

  Moreover, according to 2nd invention of this invention, melting | fusing point of a latent heat storage agent is 0-80 degreeC in 1st invention, The heat storage gel characterized by the above-mentioned is provided.

  Further, according to the third invention of the present invention, in the first or second invention, the 1/4 cone consistency defined by JIS K2220 (50 g load) of the silicone gel is 20 to 150, or JIS K2207. A heat storage gel characterized by having a penetration of 30 to 250 defined by -1980 (50 g load) is provided.

  According to the fourth invention of the present invention, in any one of the first to third inventions, the penetration of the heat storage gel defined by JIS K2207-1980 (50 g load) is 30 to 250. A heat storage gel is provided.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the silicone gel is produced by a curing reaction of a silicone compound in the presence of a microcapsule containing a latent heat storage agent in the shell. A method for producing a heat storage gel is provided.

  Moreover, according to the 6th invention of this invention, the heat storage material characterized by having enclosed the heat storage gel of any one of the 1st-4th invention in the packaging material is provided.

  Moreover, according to 7th invention of this invention, the pillow characterized by using the thermal storage material of 6th invention is provided.

  Moreover, according to the 8th invention of this invention, the mattress characterized by using the heat storage material of the 6th invention is provided.

  According to the ninth aspect of the present invention, there is provided a pet cold insulation sheet characterized by using the heat storage material of the sixth aspect.

  According to a tenth aspect of the present invention, there is provided a rear cervical cold sheet characterized by using the heat storage material of the sixth aspect.

  According to the eleventh aspect of the present invention, there is provided a sole cold sheet that uses the heat storage material of the sixth aspect.

  According to the twelfth aspect of the present invention, there is provided a warming sheet for portable warmers characterized by using the heat storage material of the sixth aspect of the present invention.

  The heat storage gel of the present invention is a heat storage gel that is excellent in moldability, weather resistance, and moisture resistance, and that can be adjusted in a wide range of hardness without causing bleeding such as oil.

  The present invention is a heat storage gel containing a silicone gel and microcapsules containing a latent heat storage agent in the shell. Below, the component of a heat storage gel, a manufacturing method, and an application are demonstrated in detail.

1. Constituent component of heat storage gel (i) Silicone gel As the silicone gel used in the present invention, a silicon compound that has been conventionally used and generally used as various commercially available silicone materials is appropriately selected and used. Can do. Accordingly, any of a heat curable type or a room temperature curable type, a condensed type or an addition type of curing mechanism can be used, and a silicone gel obtained from a two-part curable silicone composition is particularly preferable. In addition, the group bonded to the silicon atom is not particularly limited, and examples thereof include alkyl groups such as methyl group, ethyl group, and propyl group, cycloalkyl groups such as cyclopentyl group and cyclohexyl group, vinyl groups, and allyl groups. In addition to aryl groups such as alkenyl groups, phenyl groups, and tolyl groups, those in which the hydrogen atoms of these groups are partially substituted with other atoms or linking groups can be mentioned.

The silicone gel used in the present invention has a corn cone consistency of 20 to 150 defined by JIS K2220 (50 g load) after curing, or a penetration of 30 defined by JIS K2207-1980 (50 g load). It is preferable that it is -250, More preferably, the 1/4 cone consistency is 60-150, and the penetration is 50-200. When the penetration is less than 30, it is too hard and has a strong repulsive force, and when used for a pillow or mattress, a comfortable sleep cannot be obtained. On the other hand, if the 1/4 cone consistency exceeds 150, the gel is too soft and the gel may break, and the original performance may not be obtained.
Any silicone gel can be used as long as it has the above-mentioned hardness, excellent temperature characteristics, no worries about elution, does not change quality, and satisfies basic physical properties such as durability. It can be done.
Here, the 1/4 cone consistency is a value determined in accordance with JIS K2220 (50 g load), and the penetration is a value determined in accordance with JIS K2207-1980 (50 g load).

(Ii) Microcapsules in which latent heat storage agent is encapsulated in the shell The microcapsules in which latent heat storage agent is encapsulated in the shell used in the present invention is a heat storage agent that can store heat using latent heat associated with phase transition. It is encapsulated in a microcapsule. A latent heat storage agent is a substance designed to take advantage of the absorption of latent heat associated with a reversible phase transition such as a solid-liquid transition, and uses the release of latent heat during the liquid-solid phase transition. . Therefore, when this substance is used as a heat absorbing material, the temperature rises after a certain amount of heat energy is absorbed by the phase change substance, so that the object can be protected from additional heat. The phase change material can also be preheated and used as a barrier to cold, since in this case the temperature begins to drop after more heat is removed from the phase change material. The preferred latent heat storage agent for the present invention mainly utilizes a reversible solid-liquid transition.

  As the latent heat storage agent, any compound having a melting point of 0 to 80 ° C. and having a melting point or a freezing point can be used. For example, preferable compounds include n-decane, tetradecane, pentadecane, eicosane, and docosane. Examples of such a preferable compound include aliphatic hydrocarbons having 10 or more carbon atoms. Since these aliphatic hydrocarbon compounds have melting points that increase with an increase in the number of carbon atoms, it is possible to select an aliphatic hydrocarbon compound having a melting point according to the purpose, or to mix two or more kinds. In order for the heat retention function to work when the melting point of the latent heat storage agent is less than 0 ° C., the temperature of the contact object with the gel needs to be less than 0 ° C. after holding the heat storage gel at 0 ° C. or more. is there. In addition, when the melting point of the latent heat storage agent exceeds 80 ° C., the temperature of the contact object with the gel needs to exceed 80 ° C. after the heat storage gel is held at 80 ° C. or less in order to act the cold insulation function. . Considering that the use of the heat-storing gel of the present invention is mainly a heat retaining agent for humans or pets, all are in an impractical temperature range.

  The microcapsules used in the present invention are fine particles in which a latent heat storage agent is encapsulated inside the film. In general, as a method of microencapsulating a heat storage agent, an encapsulation method by a composite emulsion method (Japanese Patent Laid-Open No. 62-1452), a method of spraying a thermoplastic resin on the surface of the heat storage agent particles (JP 62-45680). ), A method of forming a thermoplastic resin in the liquid surface on the surface of the heat storage agent particles (JP-A 62-149334), a method of polymerizing and coating the monomer on the surface of the heat storage agent particles (JP-A 62-225241), an interface The method described in the manufacturing method of the polyamide membrane | film | coat microcapsule by a polycondensation reaction (Unexamined-Japanese-Patent No. 2-258052) etc. can be used.

  Microcapsule membrane materials include polystyrene, polyacrylonitrile, polyamide, polyacrylamide, ethylcellulose, polyurethane, aminoplast resin, and a core of gelatin and carboxymethylcellulose or gum arabic obtained by techniques such as interfacial polymerization and in situ. Synthetic or natural resins using the celvation method are used, but microcapsules with a thermally stable thermosetting resin film are preferred because they are mixed with the resin at high temperatures, especially aliphatic hydrocarbon compounds. A microcapsule using a urea formalin resin or melamine formalin resin film by an in-situ method capable of obtaining a microcapsule of high quality is preferable.

When the addition type silicone compound is used, if the microcapsule film material contains a compound such as phosphorus, sulfur, or amine, the curing reaction of the addition type silicone compound is inhibited. Therefore, it is preferable to use a film material that does not contain these curing inhibitors. When the use of a film material containing a curing inhibitor is unavoidable, it is preferable to perform a re-coating treatment that covers the microcapsule surface with another film material that does not contain a curing inhibitor.
If a hard resin material having a high softening point is used for the microcapsule film material, the hardness of the heat storage gel does not change even if the latent heat storage material undergoes a phase change due to a temperature change, which is preferable for use in heat storage materials such as pillows and mattresses.

  The particle size of the microcapsules used in the present invention is preferably 10 μm or less, particularly preferably 5 μm or less in order to prevent breakage due to physical pressure during the processing. The particle size of the microcapsule is the type and concentration of the emulsifier used at the time of capsule preparation, the temperature of the emulsion during emulsification, the emulsification ratio (volume ratio of water phase to oil phase), atomization called emulsifier, disperser, etc. The operation conditions (stirring speed, time, etc.) of the apparatus are adjusted as appropriate to set the desired particle size. If the particle diameter is larger than this, it is not preferable because the microcapsules are easily broken by an external pressure, or when the specific gravity of the heat storage agent is significantly different from that of the dispersion medium.

(Iii) Quantity ratio of silicone gel and microcapsule In the heat storage gel of the present invention, the quantity ratio of silicone gel and microcapsule is 90 to 10% by volume of silicone gel, preferably 60 to 30% by volume. The capsule is 10 to 90% by volume, preferably 40 to 70% by volume. When the amount of the silicone gel exceeds 90% by volume and the amount of the microcapsule is less than 10% by volume, the hardness of the heat storage gel is extremely low, and the amount of the heat storage microcapsules is low, so that the heat storage effect cannot be exhibited. When the amount of the silicone gel is less than 10% by volume and the amount of the microcapsule exceeds 90% by volume, the heat storage gel has high hardness and is difficult to process.

(Iv) Other components The heat storage gel of the present invention comprises a microcapsule containing a silicone gel and a latent heat storage agent. In addition to these components, if necessary, a heat conductive filler, an antiaging agent. , Antioxidants, plasticizers, lubricants, colorants, organic pigments, inorganic pigments, UV absorbers, heat stabilizers, light stabilizers, dispersants, fungicides, antistatic agents, flame retardants, tackifiers It is possible to add a curing agent, a foaming agent, a synthetic fiber, a synthetic resin, glass fiber, a metal fiber, a heat insulating material, a VOC removing material, activated carbon, a moisture absorbing / releasing agent, and the like.

2. Production of heat storage gel The heat storage gel of the present invention is obtained by dispersing microcapsules containing a latent heat storage agent in the shell in the silicone gel, and the production method is not particularly limited. And a method of melt-kneading a microcapsule and other additives in a melt-kneader such as a single-screw or twin-screw extruder, and a method of gelling in the presence of a microcapsule during gelation of a silicon compound Etc. Among these methods, a method in which a silicone gel is formed by a curing reaction of two types of silicon compounds in the presence of microcapsules is preferable because the microcapsules can be efficiently dispersed in the silicone gel.

3. Thermal Storage Gel The thermal storage gel of the present invention preferably has a penetration of JIS K2207-1980 (50 g load) of 30 to 250, more preferably 60 to 200. When the penetration is less than 30, it is too hard to obtain a comfortable fit when the body comes in contact, and when it exceeds 250, it is too soft to obtain an appropriate holdability when the body comes into contact. is there.
Since the heat storage gel of the present invention has the hardness as described above, it is excellent in moldability, and since it is based on a silicone resin, it is excellent in weather resistance and moisture resistance. Furthermore, since it is not necessary to adjust the hardness with oil or the like, there is a feature that bleed such as oil from the gel does not occur. Further, since the latent heat storage agent does not ooze out even after repeated use and the amount of stored heat does not decrease, it has a feature that high heat storage performance is maintained even after repeated use.

4). Use of heat storage gel The heat storage gel of the present invention is a silicone gel composition containing microcapsules containing a latent heat storage agent having a phase change. Therefore, it can be used as a cold insulating material or a heat insulating material. As a heat storage material that holds an object in a cooled or warmed state, it can be used in applications such as pillows, mattresses, pet cold sheets, rear neck cold sheets, sole cold sheets, and portable warmers.
In particular, when a heat storage gel is formed into a sheet or the like and then encapsulated and sealed in a packaging material, the strength is improved, and the gel can be used without unnecessarily adhering to an object or attaching dirt. For example, when used for a pillow or the like, the heat storage gel of the present invention is formed into a sheet, covered with a film of polyurethane or the like and heat-sealed to form a heat storage material, and the heat storage material is used between the pillow and the pillow cover, or a mattress Can be used by inserting between covers. In addition, the heat storage material covered with a film is put into a non-woven fabric or polyester bag and wound around the neck as a rear neck cold sheet, and further, the heat storage material is affixed to the sole with a medical adhesive tape or the like. It can be used as a cold insulation sheet.
Moreover, if heat storage gel is used in a lamination | stacking state with heat conductive gel, thermal conductivity will improve and a heat absorption and a thermal radiation effect will improve.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited by these examples without departing from the gist thereof.

Example 1
The viscosity at 25 ° C. is 300 mPa.s. s (A liquid) and 290 mPa.s s (Liquid B) two-part curable silicone composition (SIG-1000-A / B manufactured by Shin-Etsu Chemical Co., Ltd.) 300 g each, and heat storage microcapsule filler (Mitsubishi Paper ( FP-31M) 400 g was mixed for 15 minutes and then vacuum degassed at room temperature for 10 minutes. Heating was performed at 70 ° C. for 1 hour and further at 100 ° C. for 3 hours to obtain 1000 g of a cured product (heat storage gel). The penetration of the obtained cured product at 25 ° C. was 216, and the content of the heat storage microcapsule filler calculated from the specific gravity was 43% by volume.
On the other hand, the mixture after vacuum degassing was poured into three molds of length × width × thickness = 130 mm × 175 mm × 2.5 mm before heating and curing, and then heated at 70 ° C. for 1 hour and further at 100 ° C. for 3 hours. As a result, three gel sheets were obtained. These three sheets were arranged in close contact, covered with a polyurethane film having a thickness of 100 μm, and heat-sealed to obtain a heat storage material. The obtained heat storage material was placed between a pillow substrate made of low-resilience urethane foam and a pillow cover so that the person hit the back neck when sleeping and placing his head on the pillow. In a room set at a room temperature of 27 to 28 ° C. and a humidity of 55 to 65%, the temperature change of the pillow hit by the back neck when sleeping for 20 minutes was measured with a wave thermo (manufactured by Keyence Corporation) at n = 3. The elevated temperature is shown in Table 1.

(Example 2)
The viscosity at 25 ° C. is 300 mPa.s. s (A liquid) and 290 mPa.s s (Liquid B) two-component curable silicone composition (SIG-1000-A / B manufactured by Shin-Etsu Chemical Co., Ltd.) 250 g each, and heat storage microcapsule filler (Mitsubishi Paper ( FP-31M) (500 g) was mixed for 15 minutes and then vacuum degassed for 10 minutes at room temperature. Heating was performed at 70 ° C. for 1 hour and further at 100 ° C. for 3 hours to obtain 1000 g of a cured product (heat storage gel). The penetration of the obtained cured product at 25 ° C. was 180, and the content of the heat storage microcapsule filler calculated from the specific gravity was 53% by volume.
Moreover, the heat storage material was obtained like Example 1, and the temperature change of the pillow using the obtained heat storage material was measured. The results are shown in Table 1.

(Example 3)
The viscosity at 25 ° C. is 300 mPa.s. s (A liquid) and 290 mPa.s s (Liquid B) two-pack curable silicone composition (SIG-1000-A / B manufactured by Shin-Etsu Chemical Co., Ltd.) 225 g each, and heat storage microcapsule filler (Mitsubishi Paper ( FP-31M) (550 g) was mixed for 15 minutes and then vacuum degassed at room temperature for 10 minutes. Heating was performed at 70 ° C. for 1 hour and further at 100 ° C. for 3 hours to obtain 1000 g of a cured product (heat storage gel). The penetration of the obtained cured product at 25 ° C. was 157, and the content of the heat storage microcapsule filler calculated from the specific gravity was 58% by volume.
Moreover, the heat storage material was obtained like Example 1, and the temperature change of the pillow using the obtained heat storage material was measured. The results are shown in Table 1.

Example 4
The viscosity at 25 ° C. is 3500 mPa.s. s (Liquid A) and 2900 mPa.s s (liquid B), a two-part curable silicone composition (CF5057-A / B manufactured by Toray Dow Corning Co., Ltd.), liquid A, 393 g, liquid B, 321 g, and heat storage microcapsule filler having a melting point of 25 ° C. 286 g (Mitsubishi Paper Co., Ltd.) was mixed for 15 minutes and then vacuum degassed for 10 minutes at room temperature. Heating was performed at 70 ° C. for 1 hour and further at 100 ° C. for 3 hours to obtain 1000 g of a cured product (heat storage gel). The penetration of the obtained cured product at 25 ° C. was 83, and the content of the heat storage microcapsule filler calculated from the specific gravity was 30% by volume.
Moreover, the heat storage material was obtained like Example 1, and the temperature change of the pillow using the obtained heat storage material was measured. The results are shown in Table 1.

(Comparative Example 1)
The viscosity at 25 ° C. is 300 mPa.s. s (A liquid) and 290 mPa.s s (liquid B), a two-part curable silicone composition (SIG-1000-A / B manufactured by Shin-Etsu Chemical Co., Ltd.), liquid A 270 g, liquid B 202 g, and aluminum hydroxide (Showa Denko Co., Ltd.) HS-341) 1580 g was mixed for 15 minutes and then vacuum degassed for 10 minutes at room temperature. Heating was performed at 70 ° C. for 1 hour and further at 100 ° C. for 3 hours to obtain 2000 g of a cured product (heat storage gel). The penetration of the obtained cured product at 25 ° C. was 100, and the content of aluminum hydroxide calculated from the specific gravity was 60% by volume.
Moreover, the heat storage material was obtained like Example 1, and the temperature change of the pillow using the obtained heat storage material was measured. The results are shown in Table 1.

(Comparative Example 2)
The viscosity at 25 ° C. is 3500 mPa.s. s (Liquid A) and 2900 mPa.s 520 g of liquid A and 480 g of liquid B of the two-part curable silicone composition (CF5057-A / B manufactured by Toray Dow Corning Co., Ltd.), which is s (liquid B), were mixed for 15 minutes and then vacuum degassed for 10 minutes at room temperature. did. Heating was carried out at 70 ° C. for 1 hour and further at 100 ° C. for 3 hours to obtain 1000 g of a cured product. The penetration of the obtained cured product at 25 ° C. was 134. The temperature change of the pillow using the obtained silicone gel was measured. The results are shown in Table 1.

  As is apparent from Table 1, the temperature change of the rear neck when sleeping on a pillow containing a heat storage material for 20 minutes was as small as 0.5 to 0.6 ° C. (Examples 1 to 4). In pillows that do not contain, the temperature change was 2.0 to 2.5 ° C., which was 5 to 5 times larger (Comparative Examples 1 and 2). That is, it can be seen that the heat storage material is effective in maintaining the cooling feeling.

  The heat storage gel of the present invention is a heat storage gel that is excellent in moldability, weather resistance, and moisture resistance, and does not cause bleeding such as oil, and can be adjusted in a wide range of hardness, and can be used as a cold or heat insulating material. . As a heat storage material for holding an object in a cooled or warmed state, it can be used in applications such as pillows, mattresses, pet cold sheets, rear neck cold sheets, sole cold sheets, and portable warmers.

Claims (12)

  A heat storage gel comprising 90 to 10% by volume of silicone gel and 10 to 90% by volume of microcapsules containing a latent heat storage agent in the shell.   The heat storage gel according to claim 1, wherein the latent heat storage agent has a melting point of 0 to 80 ° C.   That the hardness of the silicone gel is corn cone consistency specified by JIS K2220 (50 g load) is 20 to 150, or the penetration specified by JIS K2207-1980 (50 g load) is 30 to 250. The heat storage gel according to claim 1 or 2, characterized in that   The heat storage gel according to any one of claims 1 to 3, wherein a penetration of the heat storage gel defined by JIS K2207-1980 (50 g load) is 30 to 250.   The heat storage property according to any one of claims 1 to 4, wherein a silicone gel is produced by performing a curing reaction of the silicone compound in the presence of a microcapsule containing a latent heat storage agent in the shell. A method for producing a gel.   A heat storage material, wherein the heat storage gel according to any one of claims 1 to 4 is enclosed in a packaging material.   A pillow comprising the heat storage material according to claim 6.   A mattress using the heat storage material according to claim 6.   A pet cold insulation sheet using the heat storage material according to claim 6.   A rear neck cold sheet using the heat storage material according to claim 6.   A sole cold sheet using the heat storage material according to claim 6.   A heat insulating sheet for portable warmers, wherein the heat storage material according to claim 6 is used.