JP2002114973A - Thermal storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal storage medium which maintains the shape of a product even when heated at a high temperature and is hard to cause thermal deformation. SOLUTION: The thermal storage medium is coated with a reversibly crosslinkable polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage material, and more particularly, to a heat storage material that maintains a product shape even when heated to a high temperature and hardly undergoes thermal deformation.

[0002]

2. Description of the Related Art Conventionally, various organic heat storage materials have been used as heat storage materials. However, these organic heat storage materials usually have a high temperature (for example, 80 ° C. or more, particularly 100 ° C.).
(1) mixing a resin (for example, a polyolefin resin such as polyethylene) or the like so as not to be fluidized at a high temperature; (2) a resin container Or put on film,
(3) It is necessary to improve the handleability at high temperatures by a method such as combining (1) and (2).

[0003]

However, in the above methods (1) to (3), there are cases where the handling at high temperatures cannot be sufficiently improved.

Specifically, for example, the heat storage temperature is increased (for example, from 80 ° C. to 150 ° C.) in order to shorten the heat storage time.
F), and even when the method (1) is employed, thermal deformation (further fluidization) of the heat storage material is likely to occur. If the control of the heat storage temperature is not sufficient, the resin container or film of the above (2) may be thermally deformed or damaged by heating.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat storage material which maintains a product shape even when heated to a high temperature and is less likely to be thermally deformed.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies on the above problems, and as a result, by using a material that can be crosslinked by heat treatment at a relatively low temperature, that is, by using a reversible crosslinkable polymer, Specifically, it has been found that by coating the surface of the heat storage material with the reversible crosslinkable polymer, the heat storage material can be provided with high temperature resistance (100 ° C. to 200 ° C. level), and the present invention has been completed. . That is, the present invention is as follows.

The heat storage material of the present invention is coated with a reversible crosslinkable polymer. Thereby, the above object is achieved.

In a preferred embodiment, the heat storage material is paraffin wax, polyethylene wax, higher alcohol and its derivatives, linear fatty acid and its derivatives, polyethylene glycols, polyhydric alcohols, sugars, sodium sulfate hydrate, chloride It is at least one selected from the group consisting of calcium hydrate and sodium acetate hydrate.

[0009] In a preferred embodiment, the heat storage material contains at least one selected from the group consisting of an olefin polymer, a thermoplastic elastomer, rubbers and a high melting point wax.

In a preferred embodiment, the reversible crosslinkable polymer comprises a backbone polymer having carboxylic anhydride groups,
And a crosslinked product having a hydroxyl group.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the present specification, the term “reversible crosslinkability” means that a crosslink dissociation reaction at a high temperature (for example, 200 ° C. to 260 ° C.) and a crosslink bond reaction at a temperature lower than the crosslink dissociation temperature can be performed reversibly. Means nature.

The heat storage material of the present invention is coated with a reversible crosslinkable polymer.

The heat storage material of the present invention is not particularly limited. Examples of the organic heat storage material include paraffin wax, polyethylene wax, higher alcohols and derivatives thereof, straight-chain fatty acids and derivatives thereof, polyethylene glycols, and the like. Polyhydric alcohols, saccharides and the like can be mentioned, and examples of the inorganic heat storage material include sodium sulfate hydrate, calcium chloride hydrate, and sodium acetate hydrate. Examples of higher alcohol derivatives include methyl stearate, sodium lauryl sulfonate, oleic amide, and octylamine. Examples of the linear fatty acid derivative include methyl stearate, sodium lauryl sulfonate, oleic amide, and octylamine.

The reversible crosslinkable polymer for coating the heat storage material of the present invention reversibly undergoes a crosslink dissociation reaction at a high temperature (eg, 200 ° C. to 260 ° C.) and a crosslink bond reaction at a temperature lower than the crosslink dissociation temperature. Has properties that can be performed. This reversible crosslinkable polymer contains a main chain polymer having a reactive group X and a crosslinked body having a reactive group Y which causes a crosslinking reaction with the reactive group X. That is, the reversible crosslinkable polymer utilizes a reversible reaction between the reactive group X and the reactive group Y as a basic reaction.
Examples of the combination (X, Y) of the reactive group X and the reactive group Y include (carboxylic anhydride group, hydroxyl group) and the like. Examples of the main chain polymer include a copolymer of an α-olefin and an ethylenically unsaturated carboxylic anhydride, and a graft polymer of an α-olefin resin with an ethylenically unsaturated carboxylic anhydride. Examples of the crosslinked body include a hydroxyl-containing compound having no hydroxyl group bonded to a primary carbon atom and having two or more hydroxyl groups bonded to a secondary carbon atom. Specific examples of the reversible crosslinkable polymer include, for example, those described in JP-A-11-106578.

The reversible crosslinkable polymer may be a composition in which a main chain polymer having a reactive group X and a crosslinked product having a reactive group Y which causes a crosslinking reaction with the reactive group X are separately compounded. .

By coating the heat storage material with such a reversible crosslinkable polymer, the molded shape can be maintained without thermal deformation even when heated to a high temperature.

The heat storage material of the present invention may further contain at least one selected from the group consisting of olefin polymers, thermoplastic elastomers, rubbers and high melting point waxes.

The olefin polymer is not particularly restricted but includes, for example, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, low density / medium density
Examples include a high-density linear ethylene polymer and a special catalyst ethylene polymer. These olefin polymers may be used alone or in combination.

The thermoplastic elastomer is not particularly restricted but includes, for example, styrene elastomers and olefin elastomers. Examples of the styrene-based elastomer include an ABA type block copolymer (A is polystyrene, B is polybutadiene, polyisoprene or ethylene / hydrogen added thereto.
And the like. Examples of the olefin-based elastomer include a mixture of an ethylene-propylene copolymer or an ethylene-propylene-diene terpolymer and polyethylene or polypropylene, and an ethylene-propylene copolymer. Examples thereof include those obtained by graft polymerization of ethylene or propylene onto a coalesced or ethylene-propylene-diene terpolymer. In particular,
Septon (trade name:
Kuraray Co., Ltd.), TUFTEC (trade name: Asahi Kasei), Clayton (trade name: Shell Japan), and the like. : Japan Polyolefin), Sumitomo TPE (trade name: Sumitomo Chemical) and the like. These thermoplastic elastomers may be used alone or in combination.

The content of the thermoplastic elastomer in the heat storage material is preferably from 0.1 to 100 parts by weight of the heat storage material.
It is 50 parts by weight, more preferably 0.1 to 30 parts by weight, most preferably 0.5 to 10 parts by weight.

Bleed can be suppressed by including such a thermoplastic elastomer in the heat storage material.

The rubbers are not particularly limited.
For example, ethylene propylene rubber, isoprene rubber (for example, DYNARON (trade name: JSR) and the like) and the like can be mentioned. These rubbers may be used alone or in combination.

The high melting point wax acts as a drop point improver, and preferably has a melting point 20 ° C. or more higher than the melting point of the heat storage material. Examples of the high melting point wax include fatty acids such as polyethylene wax, magnesium stearate, aluminum stearate, and calcium stearate and metals (eg, Li, Mg, Al, Ca, Ba, Zn, C
d, Pb, etc.), fatty acid amides (amide waxes) such as methylenebis-stearamide, ethylenebis-oleylamide, ethylenebis-stearamide, etc., and reactive drop point improvers such as polyurea.

The heat storage material of the present invention may further contain, if necessary, various additives such as an antioxidant, an antioxidant, a coloring agent, a pigment, an antistatic agent, an antifungal agent, a flame retardant, and an anti-rat agent. , Metal powder, metal fiber, metal oxide, carbon, carbon fiber and the like.

The heat storage material of the present invention may be mixed, if necessary, with an olefin polymer, a thermoplastic elastomer, rubbers and a high melting point wax, for example, using a conventional mixer / stirrer (for example, 2
The heat storage material which has been mixed and stirred using a roll, an extruder, a twin-screw kneading extruder, a stirring mixer, and the like, and then turned into a solution, as it is, or after being slightly cooled, has a desired shape. It is molded into a molded body. This shape is not particularly limited, and examples thereof include a sheet shape, a plate shape, a granular shape, and a pellet shape. The molding may be performed by pouring a heat storage material into a mold and forming a desired sheet shape or plate shape, or may be formed into a block shape and then cut into a sheet shape or a plate shape. Also, adhere or apply on films, fabrics, fibers, etc.
Alternatively, it may be impregnated into a sheet shape or a plate shape. Furthermore, it can be packed in a bag of polyethylene or the like and formed into a sheet or a plate during the cooling process.On the other hand, if an extruder is used, it can be extruded into a sheet or a plate and further extruded. It can be molded into a rod or pipe. rod,
If the pipe is chopped, it becomes granular or pellet-shaped.

Next, the molding obtained above is coated with a reversible crosslinkable polymer. A known method can be used for the coating method, and is not particularly limited.

Next, the reversible crosslinkable polymer is crosslinked at room temperature over time.
The cross-linking reaction can be promoted by performing the heat treatment.

When the obtained heat storage material is used, in principle, all of the conventional use forms of this type of heat storage material can be adopted. In particular, the heat storage material in the form of a sheet is protected by a protective film (for example, polyethylene, polypropylene, (A film of polyester or the like), and a soaking layer is further provided thereon using a metal foil such as aluminum. Further, the protective film and the metal foil may be covered with a laminate film in which the protective film and the metal foil are bonded.

The heat storage material of the present invention maintains the product shape even when heated to a high temperature, and is less likely to be thermally deformed. In particular, the heat storage water heater, the use of exhaust heat from a fuel cell, the use of exhaust heat around a car engine, It can be suitably used for garbage disposal heat utilization, car seats, and the like.

[0031]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

Example 1 100 parts by weight of paraffin wax (melting point: 80 ° C.) as a heat storage material, 7 parts by weight of a styrene-ethylene-propylene-styrene block copolymer as a thermoplastic elastomer, and 7 parts by weight of a polyethylene wax as a high melting point wax (Melting point: 120 ° C.) was mixed and stirred at 140 ° C. for 1 hour with a heater stirrer. The obtained uniform liquid was filled into a mold and molded into a plate shape.

Next, a reversible crosslinkable polymer (trade name: TRCP-01,
(Mitsubishi Chemical Co., Ltd., melting point 94 ° C.), a lid made of a reversible crosslinkable polymer was placed, and the mold was pressed at 75 ° C.
For 48 hours to crosslink the reversible crosslinkable polymer to obtain a reversible crosslinkable polymer-coated heat storage material.

The heat storage material obtained in Example 1 was left in a thermostat at 120 ° C. for 24 hours, but maintained its initial shape without deformation.

[0035]

According to the present invention, by coating with a reversible crosslinkable polymer, it is possible to obtain a heat storage material which maintains its product shape even when heated to a high temperature and hardly undergoes thermal deformation. The heat storage material of the present invention maintains the product shape over a long period of time even in a high temperature range (100 ° C. or higher, particularly 120 ° C. or higher) under the condition of using the heat storage temperature, thereby preventing deformation and breakage of the container itself at high temperature, If the bag or container breaks, it will not leak,
Since it does not have fluidity, the strength load applied to the container can be reduced, and even when a thin heat storage material is used, heat can be uniformly radiated from the surface. Further, the coating layer made of the reversible crosslinkable polymer can be recycled.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 7/04 CEZ C08J 7/04 CEZZ // C08L 101: 00 C08L 101: 00 F term (reference) 4F006 AA04 AA12 AA13 AA31 AA58 AB01 AB13 AB24 AB52 BA04 CA00 DA04 4F100 AA06B AA07B AH02B AH08B AJ03B AJ11B AK01A AK01C AK04B AR00A AR00C BA03 BA06 BA10A BA10C DD32 EJ05A EJ05C GB71 JB12A

Claims (4)

[Claims] 1. A heat storage material coated with a reversible crosslinkable polymer. 2. The heat storage material is paraffin wax, polyethylene wax, higher alcohol and its derivative, linear fatty acid and its derivative, polyethylene glycol, polyhydric alcohol, saccharide, sodium sulfate hydrate,
The heat storage material according to claim 1, which is selected from the group consisting of calcium chloride hydrate and sodium acetate hydrate. 3. The heat storage material according to claim 1, wherein the heat storage material contains at least one selected from the group consisting of an olefin polymer, a thermoplastic elastomer, rubbers and a high melting point wax. 4. The heat storage material according to claim 1, wherein the reversible crosslinkable polymer contains a main chain polymer having a carboxylic acid anhydride group and a crosslinked product having a hydroxyl group.