JPH09234216A - Sheet to coolant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for coolant easy to handle and capable of keeping an excellent cooling effect. SOLUTION: This sheet for coolant comprises a water absorptive sheet wherein a water absorptive resin is carried on a sheet-like base material and a cooling substance endothermic by contact with the water. The water absorptive resin is formed by polymerization of ethylenic unsaturated monomer contained in the base material. The water absorptive sheet 1 is carried, for example, with the water absorptive resin 2 attached along the surface layer of fiber constituting the base material 3. The cooling substance is preferably at least one selected from the group consisting of urea, ammonium chloride, ammonium nitrate, sodium nitrate, potassium nitrate and anhydrous sodium sulfate. Thereby the surface area of the water absorptive resin is enlarged, the water-holding capacity of the absorptive sheet is increased and the water taken in the gaps of the water absorptive sheet is prevented from flowing out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling sheet suitable for use as a cooling compress material for alleviating inflammation caused by injury or heat generated during exercise, and as a simple cooling material for cooling drinking water, fruits and the like. It is about.

[0002]

2. Description of the Related Art Coolants are used for leisure, sports, first aid, etc. As the cooling material, for example, a cooling compress material that alleviates inflammation due to injury or heat generation during exercise, a simple cooling material that cools drinking water, fruits, and the like are known.

As a cooling material having excellent durability of cooling effect, various gel-like cooling materials made of water-containing gel made by absorbing water in a water-absorbent resin and urea or ammonium nitrate have been proposed (JP-A-56). -147883, JP 59-49476
(Japanese Patent Laid-Open No. 60-4581).

Further, as a sheet for a coolant exhibiting cooling performance by adding water, JP-A-63-284124 discloses a water-swellable cloth-like body (water-absorbent sheet) made of water-swellable fibers. A poultice which has been made to coexist with a water cooling substance (cooling substance) has been proposed.

[0005]

However, since the water-absorbent resin is in the gel state, it is difficult to handle the gel-like coolant as it is. Therefore, it is necessary to use the gel-like cooling material by putting it in a bag or sandwiching it with a non-woven fabric or a film. Therefore, there was a problem in handleability.

On the other hand, although the above poultice is improved in handleability, since it uses a water-swellable cloth made of water-swellable fibers as a water-absorbent sheet, it can be used with water. There was a problem that water taken into the spaces between the fibers was easily spilled and polluted the surroundings.

Further, the poultice has a problem that it has a poor cooling action because the cooling substance is not fixed to the water-swellable fibers. That is, when the cooling substance is kneaded with the pressure-sensitive adhesive layer provided on one side of the water-swellable cloth, the poultice is difficult to contact with the cooling substance and is inferior in cooling action. Further, in the above poultice, when the cooling substance is not kneaded into the pressure-sensitive adhesive layer and is present between the pressure-sensitive adhesive layer and the water-swellable cloth, or on the non-sticky surface of the water-swellable cloth. The cooling substance is not fixed. For this reason, the cooling substance may spill out before use, or may flow out together with water during use, so that sufficient cooling performance may not be exhibited.

The present invention has been made to solve the above problems, and an object thereof is to provide a sheet for a coolant, which has good handleability and can maintain an excellent cooling action.

[0009]

Means for Solving the Problems The inventors of the present application have made earnest studies on a sheet for a cooling material in order to achieve the above object, and as a result, for a cooling material containing a water absorbing sheet having a specific structure and a cooling substance. It was found that the sheet has good handleability and can maintain an excellent cooling action, and completed the present invention.

That is, in order to solve the above-mentioned problems, the cooling sheet according to the first aspect of the present invention is in contact with water and a water-absorbent sheet in which a water-absorbent resin is carried on a sheet-shaped substrate. A sheet for a coolant containing a cooling substance that absorbs heat by the above, wherein the water-absorbent resin is formed by polymerizing the ethylenically unsaturated monomer contained in the base material.

According to the above construction, the water absorbent sheet is formed by polymerizing the ethylenically unsaturated monomer contained in the base material. As a result, the water absorbent resin is integrated with the base material, so that the water absorbent resin can be prevented from falling off.

Further, in the above water absorbent sheet, the surface area of the water absorbent resin is large and the water absorbent function is excellent. Thereby, the water absorbent sheet can continue the endothermic reaction between water and the cooling substance for a longer time. Therefore, the above-mentioned sheet for a coolant can maintain an excellent cooling action for a long time and is excellent in cooling performance.

Further, according to the above construction, since the water absorbent sheet is made by polymerizing the ethylenically unsaturated monomer contained in the substrate, the surface area of the water absorbent resin is large. This makes it possible to reliably prevent the water taken into the base material from flowing out.

Further, in order to solve the above-mentioned problems, the cooling material sheet according to the second aspect of the present invention is the cooling material sheet according to the first aspect, wherein the cooling substance is the surface and / or the base of the water-absorbent resin. It is characterized in that it is attached to the surface of the material.

According to the above construction, since the cooling substance is adhered to the surface of the water absorbent resin and / or the surface of the base material, the cooling substance and water can be efficiently brought into contact with each other. Further, it is possible to prevent the cooling substance from flowing out when water is added and used. With these, the cooling performance can be further improved.

According to a third aspect of the present invention, there is provided a cooling sheet,
In order to solve the above-mentioned problems, the cooling material sheet according to claim 1 is characterized in that the cooling substance is included in the water absorbent resin.

According to the above construction, since the cooling substance is contained in the water absorbent resin, it is possible to reliably prevent the cooling substance from flowing out when water is added and used. Moreover, the cooling performance can be further improved.

According to a fourth aspect of the present invention, there is provided a cooling sheet,
In order to solve the above problems, in the coolant sheet according to any one of claims 1 to 3, the cooling substance is urea, ammonium chloride, ammonium nitrate, sodium nitrate, potassium nitrate, and anhydrous sodium sulfate. It is characterized in that it is at least one compound selected from the group.

According to the above structure, the cooling performance of the coolant sheet can be further improved.

The present invention will be described in detail below. The sheet for a coolant according to the present invention comprises a water-absorbent sheet in which a water-absorbent resin is supported on a sheet-shaped base material, and a cooling substance which absorbs heat when brought into contact with water. The water absorbent resin is obtained by polymerizing the ethylenically unsaturated monomer contained in the base material.

If the above-mentioned base material is in the form of a sheet and can contain an ethylenically unsaturated monomer,
There is no particular limitation. Examples of the base material include fibrous base materials such as woven cloth, non-woven cloth, paper, and knitted fabric, sponge-like base material made of porous organic material, and lightweight aggregate made of porous inorganic material. When using a fibrous substrate as the substrate,
The materials include wood pulp, cotton, wool, rayon,
Hydrophilic fibers such as acetate fibers, vinylon and water absorbing fibers; hydrophobic fibers such as polyester, acrylic fibers, polyamide, polypropylene, polyethylene, polyurethane, glass wool and rock wool. When a sponge-like base material is used as the base material,
Examples thereof include polyacetal, polyurethane and phenol resin. Of these base materials, it is more preferable to use a fibrous base material or a sponge-like base material from the viewpoint of water absorption of the resulting water absorbent sheet. Further, among the fibrous base material or the sponge-like base material, the non-woven fabric is particularly preferable because it can be made thin, is excellent in handleability, and is excellent in economic efficiency. A composite material obtained by combining two or more of these materials can also be used as the base material.

The ethylenically unsaturated monomer is not particularly limited as long as it is a hydrophilic monomer capable of forming a water absorbent resin by polymerization. Examples of the ethylenically unsaturated monomer include (meth) acrylic acid and (meth) acrylic acid-based monomers such as alkali metal salts and ammonium salts thereof; 2- (meth) acryloylethanesulfonic acid, 2 -(Meth) acryloylpropanesulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, (meth) allylethanesulfonic acid, and unsaturated sulfonic acids such as alkali metal salts and ammonium salts thereof System monomer; (meth)
Acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and a quaternary ammonium compound obtained by quaternizing them; hydroxyalkyl (meth) acrylate, polyalkylene glycol (meth) acrylate, N-vinylacetamide, N-vinyl -2-Pyrrolidone etc. are mentioned. These ethylenically unsaturated monomers may be used alone, or two or more kinds may be appropriately mixed and used.

Of the above-exemplified monomers, it is preferable to use (meth) acrylic acid and their alkali metal salts or ammonium salts in order to further improve the water retention capacity of the water absorbent sheet. The alkali metal salt or ammonium salt of (meth) acrylic acid includes a partially neutralized product obtained by partially neutralizing (meth) acrylic acid with an alkali metal ion or an ammonium ion. Further, in the case of manufacturing a sheet for a cooling material by absorbing an aqueous solution of a cooling substance into a water-absorbent sheet, N, N-dimethylaminoethyl (meth) acrylate excellent in liquid absorbing performance for the aqueous solution of the cooling substance, and It is preferable to use a quaternary ammonium compound obtained by quaternizing them.

The weight ratio of the substrate to the water absorbent resin in the water absorbent sheet is not particularly limited, but the amount of the water absorbent resin to 100 parts by weight of the substrate is preferably in the range of 10 to 1000 parts by weight. . When the amount of the water absorbent resin is less than 10 parts by weight, the water retention property of the water absorbent resin may be reduced.
On the other hand, if it is more than 1000 parts by weight, the flexibility of the resulting water-absorbent sheet may be deteriorated and the workability may be deteriorated.

The water-absorbent sheet can be obtained by incorporating an ethylenically unsaturated monomer into a sheet-like base material and polymerizing it.

As a method of incorporating the ethylenically unsaturated monomer into the base material, a known method can be used and is not particularly limited. For example, a method of impregnating a substrate with an ethylenically unsaturated monomer and then squeezing off the excess ethylenically unsaturated monomer; a solution obtained by dissolving the ethylenically unsaturated monomer in a solvent (hereinafter, simply A method of applying a monomer solution) to a substrate; a method of spraying an ethylenically unsaturated monomer on a substrate; a method of impregnating a substrate with an ethylenically unsaturated monomer, and the like can be used. .

The solvent is not particularly limited as long as it is a liquid in which the ethylenically unsaturated monomer is dissolved. For example, hydrophilic organic solvents such as water and alcohol, and mixed solvents thereof can be used, but water is particularly preferable.

As the method for polymerizing the ethylenically unsaturated monomer contained in the base material, known methods such as thermal polymerization, photopolymerization, electron beam polymerization and ultraviolet polymerization can be used. The reaction conditions such as the temperature and pressure of the polymerization reaction may be appropriately selected according to the type of ethylenically unsaturated monomer and are not particularly limited.

When carrying out the polymerization of the ethylenically unsaturated monomer, a crosslinking agent can be added if necessary. That is, for example, the crosslinking agent may be added to the ethylenically unsaturated monomer and then added to the base material. By adding a cross-linking agent, the durability and shape stability of the resulting water absorbent sheet can be improved. Examples of the cross-linking agent include N,
A polyfunctional ethylenically unsaturated monomer such as N′-methylenebisacrylamide, polyethylene glycol diacrylate, trimethylolpropane triacrylate, etc. can be used. These cross-linking agents may be used alone or as a mixture of two or more kinds.

The amount of the cross-linking agent used is not particularly limited and may be appropriately selected depending on the type of cross-linking agent, the type of ethylenically unsaturated monomer, the conditions of the polymerization reaction and the like. Generally, the amount of the cross-linking agent used is preferably in the range of 0.001 to 10 mol% based on the ethylenically unsaturated monomer, and in the range of 0.01 to 5 mol% based on the ethylenically unsaturated monomer. Is more preferable. If the amount of the cross-linking agent used is less than 0.001 mol%, it becomes difficult to obtain the effect of the cross-linking agent.
If the amount of the cross-linking agent used is more than 10 mol%, the water absorbing performance of the resulting water absorbent sheet may deteriorate.

When carrying out the polymerization reaction of the ethylenically unsaturated monomer, additives such as a radical polymerization initiator and a thickener may be added, if necessary. As the radical polymerization initiator, persulfates such as sodium persulfate; organic peroxides; azo compounds and the like can be used. Further, as the thickener, hydroxyethyl cellulose or the like can be used. The amount of the above additive used may be adjusted according to the type of ethylenically unsaturated monomer, the conditions of the polymerization reaction, and the like.

The sheet obtained by incorporating an ethylenically unsaturated monomer into a base material and polymerizing it can be used as it is as a water absorbent sheet, but can be dried when it contains water. . The drying temperature may be appropriately selected within a range that does not cause deterioration or decomposition of the water absorbent resin.

In this way, a water-absorbent sheet in which the water-absorbent resin is carried on the base material is obtained. And, for example,
When the base material is a fibrous base material, as shown in FIG.
The water-absorbent sheet 1 is configured by carrying the water-absorbent resin 2 in a state of adhering along the surface layer of the fibers forming the base material 3.

The water-absorbent sheet in which the water-absorbent resin is carried on the base material has a greater degree of drop-off of the water-absorbent resin than the water-absorbent sheet in which the particulate water-absorbent resin is fixed on the surface of the base material via a binder or the like. It is definitely prevented. Further, since the water absorbent sheet is carried in the water absorbent sheet in a state where the water absorbent resin is adhered to the voids of the substrate, the surface area of the water absorbent resin is larger than that of the water absorbent sheet made of water absorbent fibers or the like.

The cooling substance used in the present invention is not particularly limited as long as it absorbs heat when brought into contact with water and causes a cooling action. Examples thereof include ammonium chloride, ammonium nitrate, sodium nitrate, potassium nitrate, anhydrous sodium sulfate, urea and the like. From the viewpoint of the safety of the obtained coolant sheet, urea is more preferable. The amount of the cooling substance used varies depending on the desired degree of cooling, the type of the water-absorbent resin or the base material, and is not particularly limited, but is 10 to 100 parts by weight of the water-absorbent sheet.
The range of 5000 parts by weight is more preferable, and the range of 100 to 2000 parts by weight is further preferable. When the amount of the cooling substance used is less than 10 parts by weight, the cooling effect of the coolant sheet becomes poor. If the amount of the cooling substance used is more than 5000 parts by weight, it becomes difficult to retain the cooling substance in the water absorbent sheet.

The cooling substance is preferably retained in the voids inside the water absorbent sheet or adhered to the surface of the water absorbent sheet. Above all, it is particularly preferable that the cooling substance is held in a state of being adhered to the surface of the water-absorbent resin and / or the surface of the base material or in a state of being enclosed in the water-absorbent resin. That is, for example, when the water absorbent sheet 1 is used, the cooling substance 4 is adhered to the surface of the water absorbent resin 2 as shown in FIG.
It is particularly preferable that the cooling substance 4 is included in the water absorbent resin 2 as shown in FIG. This makes it easier for the cooling substance to come into contact with water, so that it is possible to obtain a sheet for a coolant having excellent cooling performance. In addition, the cooling substance can be prevented from spilling or leaking, and the sheet for a coolant has excellent handleability.

As a method of obtaining a sheet for a cooling material, first, a method of spraying or applying an aqueous solution of a cooling substance on the surface of the water absorbent sheet; a method of spraying a liquid cooling substance on the surface of the water absorbent sheet; Examples include a method of spreading a powdery cooling substance on the surface of the water absorbent sheet. By these methods, a cooling agent sheet having a cooling substance adhered to the surface of the water absorbent resin can be obtained.

Further, as a method for obtaining a sheet for a cooling material, for example, a method in which an aqueous solution of a cooling substance is absorbed in a water-absorbing sheet; the cooling substance is added in advance before the ethylenically unsaturated monomer is contained in the substrate. It is possible to use a method of storing the information. By these methods, a cooling material sheet in which the cooling substance is incorporated into the water absorbent resin can be obtained.

As a method of obtaining a sheet for a cooling material, in addition to the above method, for example, a method of encapsulating a water-absorbent sheet in a bag together with a cooling substance; a cooling substance on the surface of the water-absorbent sheet using an adhesive or the like. It is possible to use a method of fixing the.

When the sheet for a coolant obtained by the above method contains water, it exerts a cooling action immediately after the production, so that it can be used as a coolant as it is. Further, when the cooling sheet containing water is dried to remove the water, a dried cooling sheet can be obtained. The temperature for drying the water-containing coolant sheet may be appropriately selected within a range in which water can be sufficiently removed and deterioration or decomposition of the water absorbent resin does not occur.

The dry coolant sheet exerts a cooling action by adding water. Therefore, the dried coolant sheet can be stored for a long period of time after being manufactured. When used as a coolant, water may be added just before use. The amount of water added when using the dried coolant sheet is preferably within the range of 50 to 100% by weight of the saturated water absorption of the water absorbent sheet. The amount of water added
If it is less than 50% by weight, the cooling effect may be poor or the cooling effect may not be maintained. If the amount of water added is more than 100% by weight, the water remaining unabsorbed may flow out and pollute the surroundings.

When the coolant sheet obtained by the above-mentioned method does not contain water, it is used as a coolant by adding water in the same manner as the dry coolant sheet. be able to.

When a coolant sheet containing water is used as a coolant, the cooling effect gradually decreases with the lapse of time. However, the used cooling material once again exhibits a cooling function by adding water after being dried.
Therefore, the coolant can be regenerated repeatedly. The temperature at which the coolant is dried after use may be appropriately selected within a range in which water can be sufficiently removed and deterioration or decomposition of the water absorbent resin does not occur. Moreover, you may dry under reduced pressure as needed.

If necessary, a chemical agent such as glycol salicylate, an antifreeze solution such as propylene glycol, and additives such as glycerin and ethyl alcohol may be added to the coolant sheet. These additives may be retained on the surface or inside of the water absorbent sheet by using the same method as the above cooling substance. As a result, the cooling effect, texture, and flexibility of the coolant sheet can be further improved, and the commercial value can be increased.

The cooling sheet may be used in a laminated form. Further, an adhesive layer may be provided on one side or both sides of the coolant sheet. When the water-absorbent resin is carried on one surface of the substrate, the adhesive layer is preferably provided on the side carrying the water-absorbent resin. The pressure-sensitive adhesive layer may be made of only a pressure-sensitive adhesive, but may further contain a water-absorbent resin or a crosslinking agent capable of reacting with the pressure-sensitive adhesive, a drug, or the like.

Further, the cooling sheet may be used by enclosing it in a bag made of a material such as a polymer film or a non-woven fabric. Further, the cooling sheet may be put in a box for use, or may be wrapped with a sheet material for use.

As described above, the sheet for a cooling material according to the present invention includes the water-absorbent sheet in which the water-absorbent resin is carried on the sheet-shaped base material, and the cooling substance which absorbs heat when contacted with water. It consists of The water absorbent resin is obtained by polymerizing the ethylenically unsaturated monomer contained in the base material.

According to the above constitution, since the water-absorbent resin is carried on the substrate by polymerizing the ethylenically unsaturated monomer, the surface area of the water-absorbent resin is large. Therefore, since the water absorbent sheet of the cooling sheet has excellent water absorbency, it is possible to prevent water taken into the voids of the base material from spilling from the water absorbent sheet. As a result, the handleability is good.

Further, since the surface area of the water absorbent resin is large, the water absorbent sheet has a large amount of water retention. Thereby, the endothermic reaction between water and the cooling substance can be continued for a longer time.
As a result, the cooling sheet has excellent durability of the cooling effect.

Further, in the cooling agent sheet, since the surface area of the water absorbent resin is large and the water absorbing property is excellent, it is possible to prevent the water taken in the voids of the base material from flowing out. As a result, it is possible to prevent the surrounding from being contaminated due to the outflow of water, and the handleability is good. Also,
Since the outflow of water can be prevented, the cooling effect lasts for a long time.

Moreover, since the water-absorbent sheet is obtained by polymerizing the ethylenically unsaturated monomer in the base material,
The water-absorbent resin is firmly supported on the base material. As a result, the coolant sheet can prevent the water absorbent resin from spilling from the base material and has good handleability.
In addition, it is possible to prevent the water-absorbent resin that has absorbed water and gelated during use from falling off the base material, and the cooling effect can be maintained for a long time.

Further, in the water absorbent sheet, since the water absorbent resin carried on the water absorbent sheet has a large surface area, when water is added to absorb the water, the absorbed water is easily evaporated. Therefore, a relatively large heat of vaporization can be obtained by evaporating the water. As a result, the above-mentioned coolant sheet is also excellent in the cooling effect by the heat of vaporization of water. Also,
As described above, the water-absorbent sheet has good water absorbability and a large water-retaining capacity, so that the cooling effect of the heat of vaporization of water can be maintained for a long time.

Furthermore, the coolant sheet can be easily cut into various shapes according to the purpose of use. Moreover, since the water absorbent resin is firmly adhered to the base material in the sheet for a coolant, it is possible to prevent the water absorbent resin and the cooling substance from spilling when cut.

Further, in the sheet for a cooling material, the cooling substance is adhered to the surface of the water-absorbent resin and / or the surface of the base material, or is included in the water-absorbent resin, so that the cooling substance is efficiently brought into contact with water. be able to. Therefore, the cooling effect can be improved. Further, it is possible to prevent the cooling substance from spilling or flowing out during use. As a result, not only can the surroundings be prevented from being contaminated, but the cooling effect can be maintained for a long time. Further, it is not necessary to put it in a bag or the like at the time of use, and the handleability becomes good.

[0055]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. The saturated water absorption of the water absorbent sheet was measured by the following method.

[Measurement Method of Saturated Water Absorption] First, 5 cm × 5
The water absorbent sheet having a size of cm was dried at 120 ° C. for 30 minutes, and the weight W ₀ (g) of the water absorbent sheet was measured. Next, the dried water-absorbent sheet was immersed in 100 ml of pure water for 1 hour and then suction-filtered. As a result, excess water oozing out from the water absorbent sheet and water taken between the fibers of the water absorbent sheet were almost completely removed. Then, the weight W ₁ (g) of the water absorbent sheet after filtration was measured, and from W ₀ , W ₁ and the area S (m ² ) of the water absorbent sheet (= 0.0025), the saturated water absorption amount (g / The saturated water absorption was calculated according to m ² ) = (W ₁ −W ₀ ) / S.

Example 1 In this example, partially neutralized sodium acrylate obtained by neutralizing 99 mol% of acrylic acid with sodium hydroxide was used as the ethylenically unsaturated monomer. First, 40 of partially neutralized sodium acrylate
A reaction solution was prepared by adding N, N′-methylenebisacrylamide as a crosslinking agent, sodium persulfate as a radical initiator, and hydroxyethyl cellulose as a thickener to a wt% aqueous solution. N, N'-methylenebisacrylamide was added in an amount of 0.08 mol and sodium persulfate was added in an amount of 1.0 g based on 1 mol of partially neutralized sodium acrylate. Further, hydroxyethyl cellulose was added so as to be 1.5% by weight with respect to partially neutralized sodium acrylate.

Then, dissolved oxygen in the reaction solution was removed with nitrogen gas. After impregnating the reaction liquid into a polypropylene / polyethylene non-woven fabric (base material) having a basis weight of 24 g / m ² ,
Excess reaction liquid was squeezed out with a roller. Next, this impregnated product was heated under a nitrogen atmosphere to polymerize the reaction liquid. As a result, a water absorbent sheet having a thickness of 0.5 mm was obtained. The water absorbent sheet thus obtained carried 50 g of water absorbent resin per 1 m ² . The saturated water absorption of the water absorbent sheet is 7500 g /
It was m ^2.

50% of urea (cooling substance) is added to the water absorbent sheet.
% Aqueous solution and then dried. This allows
1800 g of urea per m ² was attached to the water-absorbent sheet, and the sheet for cooling material according to the present invention was obtained.

After adding pure water having a water temperature of 23 ° C. to the obtained sheet for a coolant, the surface temperature was measured. The surface temperature after 3 minutes was 4.5 ° C. and the surface temperature after 4 hours was 17.5 ° C. It was

Further, one surface of the above-mentioned sheet for cooling material was made to be perpendicular to the ground and applied to the affected area which is the surface to be cooled. As a result, the affected area could be cooled sufficiently without the water flowing down or the swelling and gelling water-absorbent resin falling off.

Further, after the used water-containing gel-like sheet for cooling material was dried, pure water having a water temperature of 23 ° C. was added again and reused. When the surface temperature of the coolant sheet was measured,
The surface temperature after 3 minutes from the addition of pure water was 9 ° C, and after 4 hours was 19 ° C. The sheet for a cooling material of this example did not drop out or leak out of the water absorbent resin or the cooling substance, was excellent in durability, and could be repeatedly used.

Example 2 The water absorbent sheet obtained in Example 1 was saturated with pure water having a water temperature of 23 ° C. Immediately thereafter, 1 m ^{2 of} ammonium chloride was applied to the surface of the water absorbent sheet.
It was evenly applied so that the amount was 1000 g, to obtain a sheet for a coolant according to the present invention.

The surface temperature of the obtained cooling sheet was measured. As a result, the surface temperature 3 minutes after applying ammonium chloride was 9 ° C., and the surface temperature 4 hours later was 19 ° C.
Further, the cooling sheet of this example had a thin thickness of 1.5 mm and was easy to handle.

[Comparative Example 1] As a water absorbent sheet for comparison, a water absorbent fiber sheet having a saturated water absorption of 1100 g / m ² , a thickness of 0.7 mm and a basis weight of 80 g (trade name "Lanseal", manufactured by Toyobo Co., Ltd.) Was used. A water temperature of 23
Saturated water was absorbed by pure water at ℃. Immediately thereafter, urea, which is a cooling substance, was applied to the surface of the water-absorbent fiber sheet per 1 m ²
It was evenly applied to 1000 g to prepare a comparative coolant sheet.

The surface temperature of the obtained comparative cooling agent sheet was measured. As a result, the surface temperature 3 minutes after applying urea was 19 ° C. and the surface temperature after 4 hours was 23 ° C. Further, one surface of the comparative sheet for cooling material was made perpendicular to the ground, and the sheet was applied to the affected area which is the surface to be cooled. As a result, the water taken in the spaces between the fibers leaked out and contaminated the surrounding area.

After drying the comparative coolant sheet, water having a water temperature of 23 ° C. was added again and reused. When the surface temperature was measured, the surface temperature after 3 minutes was 21 ° C,
The surface temperature after 3 hours was 23 ° C.

When the cooling sheet for comparison was reused, the cooling performance was deteriorated. It is considered that this is because the cooling substance flowed out together with the water in the interstices between the fibers of the water absorbent fiber sheet during use.

Comparative Example 2 ^On a paper having a basis weight of 20 g / m ² , a powdery water-absorbent resin (trade name “IM-1000”, manufactured by Sanyo Kasei Co., Ltd.) was added at a rate of 50 g per 1 m ^2. Then, urea was further spread at a rate of 50 g per 1 m ² . Then, a paper having a basis weight of 20 g / m ² was overlaid thereon and embossed. Further, this was sandwiched between two perforated polyethylene films, and the edges of both films were heat-sealed to produce a comparative coolant sheet.

The obtained coolant sheet for comparison was placed on the water temperature.
When the surface temperature of the sample was measured after adding 3000 g of pure water at 23 ° C per 1 m ² , the surface temperature after 3 minutes was 11
° C.

Further, one side of the comparative cooling agent sheet was made perpendicular to the ground and applied to the affected area which is the surface to be cooled. As a result, the swollen and gelled water-absorbent resin moved downward, and the affected area could not be cooled sufficiently.

As is clear from the results of Examples 1 and 2 and Comparative Examples 1 and 2, the cooling agent sheet according to this example has better handleability as compared with the cooling agent sheet of Comparative Example. It was found that the excellent cooling action can be maintained without polluting the surroundings during use.

[0073]

EFFECTS OF THE INVENTION The sheet for a cooling material of the present invention includes a water-absorbent sheet having excellent water absorption and has excellent water retention, so that it has an effect that it can be cooled for a longer period of time than before. Further, since the water and the cooling substance can be efficiently brought into contact with each other, an extremely high cooling effect is exhibited. Furthermore, the sheet for a coolant contains a water-absorbent sheet having excellent water-absorbency, so that it is possible to prevent water taken into the gaps inside the water-absorbent sheet from leaking out. As a result, it is possible to prevent the surroundings from being contaminated.

Further, since the water absorbent resin is prevented from falling off, the cooling sheet can be made thin.
It is possible to provide a coolant excellent in handleability, workability, processability, storability, and aesthetics. Further, in the sheet for a cooling material, the cooling substance is adhered to the surface of the water-absorbent resin and / or the surface of the base material, or is included in the water-absorbent resin, whereby the falling of the cooling substance can be more reliably prevented. it can. Thereby, the cooling effect can be further improved.

Therefore, the sheet for a cooling material of the present invention can be used for medical / emergency, leisure, portable, transportation and the like. Specifically, it can be used as a cooling agent or cooling agent for cooling drinking water (glass, cup) such as liquor and beer, food, seafood, fruits, fresh flowers, plants, bottling, canned food, ice packs, etc. Can be used. In addition, the coolant sheet of the present invention can also be used as a cooling agent that constitutes a cooler or an ice box. Further, it is also suitably used as a coolant for tanks such as reagents that dislike high temperatures and as a coolant for suppressing heat generation of lighting equipment.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a water absorbent sheet that constitutes a coolant sheet according to the present invention.

FIG. 2 is a plan view of a main part showing a configuration of the cooling agent sheet.

FIG. 3 is a plan view of a main part showing another configuration of the cooling sheet.

[Explanation of symbols]

 1 Water absorbent sheet 2 Water absorbent resin 3 Base material 4 Cooling substance

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuyuki Harada Inventor Nobuyuki Harada 1 992, Nishioki, Okihama, Aboshi-ku, Himeji-shi, Hyogo Nihon Shokubai Co., Ltd.

Claims (4)

[Claims] 1. A coolant sheet comprising a water-absorbent sheet in which a water-absorbent resin is supported on a sheet-shaped base material, and a cooling substance which absorbs heat when contacted with water. The resin is a sheet for a cooling material, which is obtained by polymerizing an ethylenically unsaturated monomer contained in a base material. 2. The cooling sheet according to claim 1, wherein the cooling substance is adhered to the surface of the water absorbent resin and / or the surface of the base material. 3. The sheet for a cooling material according to claim 1, wherein the cooling substance is included in the water absorbent resin. 4. The cooling substance is at least one kind of compound selected from the group consisting of urea, ammonium chloride, ammonium nitrate, sodium nitrate, potassium nitrate, and anhydrous sodium sulfate. A sheet for a coolant according to item 1.