Foot warming device and method of using the foot warming device

Abstract

According to the foot warmer and method of use of the present invention, it is possible to obtain a warming effect and sensation similar to a foot bath by soaking the feet in warm water, while being easy to use. [Solution] The foot warmer 1 of the present invention comprises a first sheet 12, a second sheet 13, and a heat storage unit 14 positioned between the two sheets 12 and 13, which absorbs energy supplied from the outside and stores heat. The first sheet 12 is permeable to liquid, and the second sheet 13 is poorly permeable to liquid. The foot warmer 1 is used by supplying hot water to the heat storage unit 14, or by supplying water to the heat storage unit 14 and heating the water with electromagnetic waves, and then wearing it on the foot.

Description

[Technical Field]

[0001] The present invention relates to a foot warming device and a method for using the foot warming device. [Background technology]

[0002] A foot bath is a type of bathing where only the feet are immersed in warm water. The feet are prone to poor blood circulation and are easily affected by cold, so a foot bath is an excellent way to warm the feet and improve blood flow while remaining clothed. Another benefit of foot baths is that they can lower the body's core temperature, promoting sleep.

[0003] However, conventional foot baths require a large amount of hot water to be prepared, as they involve immersing the feet in hot water, which makes preparation and cleanup time-consuming. Therefore, as a foot warming device that does not require a large amount of hot water, the applicant previously proposed a foot bath steam heater (Patent Document 1) that has a bag-shaped foot housing with a space for accommodating the feet, a steam generating unit containing an oxidizable metal, water, an electrolyte, and a reaction accelerator provided in the foot housing, and a narrow strip-shaped fixing device attached near the opening of the foot housing. As another foot warming device that does not require a large amount of hot water, Patent Document 2 describes a water-repellent foot bath bag in which a nonwoven or woven fabric is set and a predetermined amount of mixed liquid and the feet are contained. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2008-86688 [Patent Document 2] Japanese Patent Publication No. 2015-196031 [Overview of the project] [Problems that the invention aims to solve]

[0005] Foot warmers should be easy to use while providing a warming effect and sensation similar to a foot bath. However, while conventional foot warmers are easy to use, they sometimes fail to provide the same warming effect and sensation as a foot bath with warm water. Even with the foot warming devices disclosed in Patent Documents 1 and 2, it was sometimes difficult to obtain a warming effect and sensation similar to a foot bath by immersing the feet in warm water.

[0006] The present invention relates to a foot warmer and a method for using the foot warmer, which can be used easily while providing a warming effect and sensation similar to a foot bath by immersing the feet in warm water. [Means for solving the problem]

[0007] The present invention relates to a foot warmer comprising a first sheet, a second sheet, and a heat storage unit disposed between the two sheets that absorbs energy supplied from the outside and stores heat. In one embodiment, it is preferable that the first sheet is permeable to liquid and the second sheet is poorly permeable to liquid. In one embodiment, it is preferable to use the foot warmer by supplying hot water to the heat storage unit, or by supplying water to the heat storage unit and heating the water with electromagnetic waves, before attaching it to the foot.

[0008] The present invention also relates to a method for using a foot warming device. In one embodiment, it is preferable that the foot warmer comprises a first sheet, a second sheet, and a heat storage unit disposed between the two sheets that absorbs energy supplied from the outside and stores heat. In one embodiment, it is preferable that the first sheet of the foot warmer is permeable to liquid and the second sheet is poorly permeable to liquid. In one embodiment, it is preferable to use the foot warmer by supplying hot water to the heat storage unit, or by supplying water to the heat storage unit and heating the water with electromagnetic waves, before attaching it to the foot. [Effects of the Invention]

[0009] According to the foot warmer of the present invention and the method of using the same, a warming effect and feeling similar to foot bath in which feet are immersed in warm water can be obtained while being easily used.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1 is a view showing an embodiment of the foot warmer of the present invention, and is a schematic plan view of the foot warmer in a deployed and extended state as viewed from the foot-facing surface side. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. [Figure 3] FIGS. 3(a) and (b) are perspective views showing an example of a method of attaching the foot warmer of FIG. 1 to the foot. [Figure 4] FIG. 4 is a perspective view showing a wearing state of the foot warmer held by an example of the holding means. [Figure 5] FIG. 5 is a cross-sectional view taken along line III-III of FIG. 4. [Figure 6] FIGS. 6(a) and (b) are views showing another example of the holding means, and are perspective views showing a method of attaching the foot warmer provided with the holding means. [Figure 7] FIG. 7(a) is a graph showing changes in skin temperature, and FIG. 7(b) is a graph showing changes in blood flow rate.

Embodiments for Carrying Out the Invention

[0011] The present invention relates to a foot warmer having a first sheet, a second sheet, and a heat storage part disposed between both sheets and absorbing externally supplied energy to accumulate heat, The first sheet is liquid-permeable, and the second sheet is liquid-impermeable, The present invention relates to a foot warmer that is worn and used after supplying warm water to the heat storage part or after supplying water to the heat storage part and heating the water by electromagnetic waves. Hereinafter, the present invention will be described based on its preferred embodiments with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are basically schematic, and the ratios of the dimensions etc. may be different from the actual ones.

[0012] In FIGS. 1 to 5, an embodiment of the foot warmer 1 of the present invention is shown. The foot warmer 1 of this embodiment is a wearable that is worn on the foot and warms the foot. In this specification, "foot" means the part from the ankle to the tip, and anatomically includes the heel, midfoot, and toes. The foot warmer 1 of this embodiment has a longitudinal direction X corresponding to the longitudinal direction of the sole (the back of the foot) and a width direction Y orthogonal to the longitudinal direction X. The foot warmer 1 of this embodiment has an outer shape that is line-symmetric with respect to a virtual straight line CL that extends in the longitudinal direction X by bisecting the entire length in the width direction Y and has a shape that is long in one direction in a plan view in the unfolded state (see FIG. 1). More specifically, the foot warmer 1 of this embodiment has a rectangular shape that is long in the longitudinal direction X.

[0013] In this specification, the "unfolded state" means a state in which the foot warmer 1 is spread out flat. When the foot warmer 1 includes an elastic member described later, the state in which the elastic member is stretched to the maximum and spread out flat until it becomes the same as the dimensions in the unfolded state, that is, the state in which the influence of the elastic member is completely eliminated, is also referred to as the "unfolded and stretched state". FIG. 1 shows the foot warmer 1 in the unfolded and stretched state.

[0014] The foot warmer 1 of this embodiment has a heat storage main body 10 and a pair of three-dimensional cuffs 16, 16 arranged on both sides of the heat storage main body 10. The heat storage main body 10 has a first sheet 12, a second sheet 13, and a heat storage part 14 arranged between both sheets 12, 13 (see FIG. 1). This heat storage main body 10 forms the main body of the foot warmer 1. In the heat storage main body 10 of this embodiment, the first sheet 12 forms the foot-facing surface of the heat storage main body 10, and the second sheet 13 forms the non-foot-facing surface of the heat storage main body 10. The foot warmer 1 of this embodiment comprises a first sheet 12, a second sheet 13, a heat storage section 14, and three-dimensional cuffs 16, 16 arranged on the foot-facing side of the first sheet 12, which are integrated together by known joining means such as adhesives and heat fusion.

[0015] In this specification, "foot-facing surface" refers to the surface of the foot warmer 1 or its components (e.g., heat storage section 14) that faces the surface of the wearer's foot when the foot warmer 1 is worn, i.e., the side that is relatively closer to the surface of the wearer's foot, and "non-foot-facing surface" refers to the surface of the foot warmer 1 or its components that faces away from the surface of the foot when the foot warmer 1 is worn, i.e., the side that is relatively farther from the surface of the wearer's foot. Here, "wearing state" means the normal and proper wearing position, i.e., the state in which the correct wearing position of the foot warmer 1 is maintained.

[0016] In this embodiment, the heat storage body 10 has a first sheet 12 that is permeable to liquid and a second sheet 13 that is poorly permeable to liquid. Because the first sheet 12 is permeable to liquid, hot water or water supplied from the side of the first sheet 12 can pass through the first sheet 12 and reach the heat storage section 14. Furthermore, because the second sheet 13 is impermeable to liquid, leakage of hot water or water supplied to the heat storage body 10 to the outside can be suppressed. As liquid-permeable sheets, single-layer or multi-layer nonwoven fabrics, woven fabrics, knitted fabrics, perforated films, etc., can be used.

[0017] The first sheet 12 preferably has a water permeability time of 1 minute or less, as measured by the following measurement method. <Method for measuring water permeability> Two cylinders with an inner diameter of 35 mm are positioned with their axes aligned in a straight line, and the sheet to be measured is sandwiched and fixed between the two cylinders. Then, 50 mL of water (25°C) is supplied into the upper cylinder in less than 1 second, and the time until 45 mL of water is discharged from the lower cylinder is measured.

[0018] Liquid impermeability is a concept that includes liquid opacity, encompassing properties such as complete density to liquids and water repellency. Examples of liquid impermeable sheets include liquid impermeable resin films and laminates of liquid impermeable resin films and nonwoven fabrics. The resin film is preferably made of synthetic resin and may be single-layer or multi-layer (two or more layers). The liquid-impermeable sheet preferably has a water pressure resistance of 100 mm or more, more preferably 200 mm or more, and even more preferably 500 mm or more, as measured in accordance with the JIS L1092B method. Furthermore, from the viewpoint of suppressing the rigidity of the heat storage body 10 and improving the ability of the foot warmer 1 to conform to the shape of the foot, the water pressure resistance is preferably 50,000 mm or less, more preferably 30,000 mm or less, and even more preferably 10,000 mm or less.

[0019] The foot warmer 1 of this embodiment has a pair of three-dimensional cuffs 16, 16 on both sides of the heat storage body 10 along the longitudinal direction X, which stand upright on the skin side of the wearer when the foot warmer 1 is worn (see Figure 2). Each three-dimensional cuff 16 includes a cuff-forming sheet 16b that is folded back so as to have a folded portion at the inner end in the width direction Y, and an elastic member 16a (hereinafter also referred to as "cuff elastic member 16a") fixed between the folded cuff-forming sheets 16b, 16b in an extended state in the longitudinal direction X. The outer portion of the three-dimensional cuffs 16, 16 in the width direction Y is joined to other components adjacent to the three-dimensional cuff 16 (such as the first sheet 12) by known joining means such as adhesive, while the inner portion of the cuff in the width direction Y is not joined to other components. As a result, the outer end in the width direction Y of the three-dimensional cuff 16 stands upright as the base end, and the inner end in the width direction Y is the free end. The three-dimensional cuff 16 may have a folded portion in the upright portion that stands on the side facing the foot. In this case, the portion between the folded portion and the free end may extend outward in the width direction Y, or inward in the width direction Y. In the former case, the three-dimensional cuff 16 is folded outward at the folded portion in a cross-sectional view along the width direction Y of the foot warming device 1, while in the latter case, the three-dimensional cuff 16 is folded inward at the folded portion in the same cross-sectional view.

[0020] In this embodiment, the three-dimensional cuff 16, when unfolded, has a plurality of cuff elastic members 16a extending in the longitudinal direction X, arranged at intervals in the width direction Y. The plurality of cuff elastic members 16a are arranged parallel to each other. The pair of three-dimensional cuffs 16, 16 extend along the longitudinal direction X and have non-erect joints 16d, 16d located at both ends of the foot warmer 1 in the longitudinal direction X, and erected parts 16s located between the non-erect joints in the longitudinal direction X. The erected parts 16s are the parts in which the three-dimensional cuff 16 stands up due to the elastic stretchability of the cuff elastic member 16a, and by standing up on the skin side, the erected parts 16s prevent the outflow of water supplied to the foot warmer 1 in the width direction Y. The non-erect joints 16d do not have the ability to stand up because the cuff forming sheet 16b is joined to the first sheet 12 by known joining means such as an adhesive.

[0021] The foot warmer 1 of this embodiment has side flap sections SF, SF, which are made of sheets extending outward in the width direction Y from the heat storage section 14. That is, the side flap section SF is a sheet portion of the foot warmer 1 that extends outward in the width direction Y from the heat storage section 14. The side flap section SF of this embodiment is made up of a cuff-forming sheet 16b, a first sheet 12, and a second sheet 13, located outward in the width direction Y from the heat storage section 14. The side flap section SF has a foot-facing surface formed by the cuff-forming sheet 16b, and a non-foot-facing surface formed by the second sheet.

[0022] The foot warmer 1 of this embodiment includes a side cuff elastic member 15a fixed in an extended state in the longitudinal direction X at the side flap portion SF. That is, the side cuff elastic member 15a is arranged on both side edges of the foot warmer 1 along the longitudinal direction X. In this embodiment, the side flap portion SF is provided with a side cuff elastic member 15a extending in the longitudinal direction X between the first sheet 12 and the second sheet 13. The side cuff elastic member 15a is fixed at both ends in the longitudinal direction X between the first sheet 12 and the second sheet 13 with an adhesive or the like. As the side cuff elastic member 15a contracts in the longitudinal direction X, gathers extending in the longitudinal direction X are formed in the side flap portion SF. The foot warmer 1 is equipped with elastic members that expand and contract in the longitudinal direction X, such as the side cuff elastic member 15a and the cuff elastic member 16a, which allows it to maintain the folded state described later and improves its close fit to the foot.

[0023] The heat storage unit 14 has the function of absorbing energy supplied from the outside and storing heat. The heat storage unit 14 can store heat by absorbing a heat transfer medium supplied from the outside, or by absorbing electromagnetic waves supplied from the outside, such as microwaves. The heat storage unit 14 of this embodiment has absorption capabilities for heat transfer media such as water, and by absorbing the heat transfer media, it is possible to store (store heat) the thermal energy contained in the heat transfer media. The heat storage unit 14 can store heat by supplying hot water, or by heating the water absorbed by the heat storage unit 14 with electromagnetic waves after water has been supplied. The amount of hot water or water supplied to the heat storage unit 14 is preferably 50 mL to 800 mL, more preferably 100 mL to 600 mL, and even more preferably 150 mL to 400 mL, from the viewpoint of providing the user with an excellent heating effect and a sensation similar to a foot bath. The amount of hot water or water supplied to the heat storage unit 14 is preferably 1 to 80 times the total mass of the foot warmer 1, more preferably 2 to 50 times, and even more preferably 3 to 50 times, from the viewpoint of providing the user with an excellent heating effect and a sensation similar to a foot bath.

[0024] The heat storage section 14 of this embodiment includes a heat storage core 40 containing a heat storage material. The heat storage section 14 of this embodiment also includes a core wrap sheet 43 that covers the heat storage core 40, and the heat storage core 40 can be appropriately made from a polymer material and an inorganic material with heat storage properties such as diatomaceous earth or ceramic as the heat storage material. As a typical example, the heat storage core 40 of this embodiment contains a polymer material 42 and a fiber material 41, which are heat storage materials.

[0025] In this embodiment, the foot warmer 1 is heated in the heat storage section 14 before being attached to the feet. In the heat storage state, the water held by the heat storage section 14 is at least higher than room temperature (25°C). The heat storage section 14 in this embodiment absorbs hot water supplied from the first sheet 12 of the foot warmer 1 and enters the heat storage state. Alternatively, after water is supplied from the first sheet 12 of the foot warmer 1, the heat storage section 14 enters the heat storage state by exposing the foot warmer 1 to electromagnetic waves to heat the water absorbed by the heat storage section 14. In this case, electromagnetic waves can be applied to the foot warmer 1 (heat storage section 14) using a microwave oven or the like. Before attaching the foot warmer 1 to the feet, it is preferable that the temperature of the heat storage section 14 be between 35°C and 80°C, from the viewpoint of providing the user with an excellent warming effect and a sensation similar to a foot bath. Furthermore, from the viewpoint of achieving a comfortable user experience without overheating, it is even more preferable that the temperature of the heat storage section 14 be between 40°C and 60°C.

[0026] Figure 3 shows an example of how to attach the foot warmer 1 of this embodiment to the foot. For ease of explanation, the holding means 2, which will be described later, is not shown in Figure 3. When attaching the foot warmer 1 of this embodiment to the foot, first, the foot warmer 1 is unfolded with the first sheet 12 facing upwards, and the foot F is placed on the first sheet 12 [see Figure 3(a)]. The foot F is positioned with the longitudinal direction of the sole aligned with the longitudinal direction X of the foot warmer 1, with the heel positioned at one end of the longitudinal direction X of the foot warmer 1 (heat storage body 10) and the toes positioned towards the center of the longitudinal direction X of the foot warmer 1. Next, the other end of the foot warmer 1 in the longitudinal direction X, that is, the part 1t in the longitudinal direction X where the foot is not placed, is folded back and placed over the dorsum of the foot (top of the foot) [see Figure 3(b)]. In this way, by folding the foot warmer 1 in half along its longitudinal direction X, the first sheet 12 faces the sole and dorsum of the foot, and the surface of the foot is covered by the foot warmer 1 (see Figure 5). As shown in Figure 3(b), a folded portion b1 is formed in the folded foot warmer 1 along the width direction Y.

[0027] As shown in Figure 5, the foot warmer 1 is deformed to conform to the shape of the foot and attached to the foot. In this embodiment, the foot warmer 1 is folded in half along the longitudinal direction X, so that it covers the surface of the dorsum and the sole of the foot. In this attached state, the foot warmer 1 has a sole portion 1b that is positioned on the sole of the foot and a dorsum portion 1t that is positioned on the dorsum of the foot.

[0028] In this embodiment, the foot warmer 1, with its heat storage unit 14 in a heat-storage state, is worn as shown in Figure 4, for example, and the heat storage unit 10 is brought into contact with the wearer's feet to warm them. This provides a warming effect similar to a foot bath, where the feet are soaked in warm water. Moreover, unlike a foot bath, the foot warmer 1 does not require a large amount of warm water, so it can be used easily without the hassle of preparation or cleanup. Furthermore, in the foot warmer 1 of this embodiment, the first sheet 12 is a liquid-permeable sheet, and the second sheet 13 is a liquid-impermeable sheet. With this configuration, when worn, water vapor generated from the heat storage body 10 moistens the feet through the first sheet 12. This provides a sensation similar to a foot bath. Thus, according to the foot warmer 1 of this embodiment, it is possible to obtain a warming effect and sensation similar to a foot bath by soaking the feet in warm water, while being easy to use. There are no particular restrictions on the application time of the foot warmer 1 of this embodiment, and it can be used for any time desired by the user. However, from the viewpoint of using it as an alternative to a foot bath in warm water, the application time is preferably 5 minutes or more and 30 minutes or less, and more preferably 10 minutes or more and 20 minutes or less.

[0029] The heat storage material preferably contains a polymer material 42 capable of forming a hydrogel by absorbing water, and it is preferable that the polymer material 42 absorbs hot water supplied from the outside and stores heat. This polymer material 42 makes it possible to absorb hot water supplied from the outside and store heat. As the polymer material 42, it is preferable to use a water-absorbing polymer that swells upon contact with water and can absorb and retain water, from the viewpoint of providing the user with an excellent warming effect and a sensation similar to a foot bath. As the water-absorbing polymer, for example, a crosslinked polymer or copolymer of acrylic acid or alkali metal acrylate, a crosslinked polymer of polyacrylic acid and its salts and polyacrylate graft polymer, a crosslinked polymer of starch or carboxymethylated cellulose, a crosslinked polymer of hydrolysis products of starch-acrylate graft copolymer, a crosslinked polymer of vinyl alcohol-acrylate copolymer, a crosslinked polymer of maleic anhydride-grafted polyvinyl alcohol, a crosslinked isobutylene-maleic anhydride copolymer, a saponified vinyl acetate-acrylic acid ester copolymer, etc. The water-absorbing polymer may also be a pulverized water-absorbing polymer that has undergone surface crosslinking treatment. The shape of the superabsorbent polymer is not particularly limited and may be spherical, lumpy, cylindrical, or amorphous, or it may be fibrous.

[0030] As the fiber material 41, either hydrophilic fibers or hydrophobic fibers, or both, can be used. Examples of hydrophilic fibers include natural fibers such as wood pulp (coniferous pulp, hardwood pulp, etc.) and non-wood pulp (cotton pulp, hemp pulp, etc.); modified pulp (cationic pulp, mercerized pulp, etc.) (all cellulose-based fibers); and hydrophilic synthetic fibers. These can be used individually or in combination of two or more. As hydrophobic fibers, fibers made of synthetic resins such as thermoplastic resins can be used. Examples of constituent resins for hydrophobic fibers include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic acid, polyalkyl methacrylate, polyvinyl chloride, polyvinylidene chloride, etc., and one of these can be used alone or in combination of two or more.

[0031] In the heat storage core 40, it is preferable that the polymer material 42 is held by the fiber material 41. With this configuration, even if a load from the foot is applied to the heat storage section 14 when worn, the movement of the polymer material 42 within the heat storage core 40 can be suppressed, and a good wearing comfort can be further maintained. The term "held" above means a configuration in which a plurality of polymer materials 42 are embedded in a mass of fiber material 41, as shown in Figure 2. In this configuration, some of the polymer material 42 may be exposed on the surface of the heat storage core 40. The mass ratio of the fiber material 41 to the polymer material 42 is preferably 0.1 to 10, and more preferably 0.5 to 6, from the viewpoint of providing the user with a superior warming effect and a sensation closer to a foot bath.

[0032] The core wrap sheet 43 maintains the shape of the heat storage core 40 by covering it. In this embodiment, since the core wrap sheet 43 is a liquid-permeable sheet, water supplied from the outside can reach the heat storage core 40 through the core wrap sheet 43. The liquid-permeable sheet used for the core wrap sheet 43 can be the same as the first sheet 12 described above.

[0033] In this embodiment, the foot warmer 1 warms the wearer's feet by directly contacting the heat-storing body 10, which is in a heat-storing state. Therefore, it is preferable that the foot warmer 1 and the feet are in close contact. From this viewpoint, it is preferable that the foot warmer 1 has deformability that can follow the shape of the foot. In other words, it is preferable that the foot warmer 1 is configured to be bendable along the shape of the foot. The deformability of the foot warmer 1 can be adjusted by the material of the forming material of each part of the foot warmer 1 (for example, the heat-storing part 14) and the basis weight of the forming material of each part. As an example, from the viewpoint of more reliably providing the above-mentioned deformability, the bending rigidity of the foot warmer 1 can be designed to be preferably 0.01N / width 6cm or more and 10N / width 6cm or less, more preferably 0.01N / width 6cm or more and 3N / width 6cm or less. The bending stiffness can be measured using the bending strength testing machine "RTA-500" (manufactured by Orientec Co., Ltd.) as follows. First, a rectangular test specimen with a length of 10 cm in the longitudinal direction X and a width of 6 cm in the width direction Y is cut from the part of the foot warmer 1 where the heat storage section 14 is located. Next, the test specimen is supported at both ends in the longitudinal direction X with a span distance of 50 mm. Under these conditions, a load is applied to the center of the longitudinal direction X of the test specimen using a pressing member with a width of 50 mm and a tip radius of 5 mm, and the load value is measured. At this time, the crosshead speed of the pressing member is set to 20 mm / min. The maximum value of the measured load value is taken as the bending stiffness value.

[0034] The foot warmer 1 of this embodiment can more effectively warm the surface of the foot by using the weight of the water absorbed by the polymer material 42 of the heat storage section 14 to bring the heat storage body 10 into suitable contact with the top of the foot and toes. From the viewpoint of further improving this effect, the foot warmer 1 preferably has the following configuration. From the viewpoint of providing the user with a superior warming effect and a sensation similar to a foot bath, the heat storage section 14 preferably has an absorption rate of 0.05 mL / cm³ per unit area. 2 More than 6mL / cm 2 More preferably, 0.5 mL / cm³ 2 More than 3mL / cm 2 The following is more preferably 1 mL / cm³ 21.5 mL / cm or more 2 It is as follows. The absorption amount per unit area is obtained by dividing the saturated water absorption amount of the water in the heat storage part 14 by the area of the heat storage part 14 in plan view (saturated water absorption amount of the water in the heat storage part 14 / area of the heat storage part 14). The saturated water absorption amount of the water in the heat storage part 14 is measured by the following method. The entire heat storage part 14 is immersed in a water bath of 5 L or more and left standing for 30 minutes. Then, the heat storage part 14 is taken out, hung in a folded state for 30 minutes to drain the water, and then the weight (weight a described later) is measured. The saturated water absorption amount is calculated from the following formula. Saturated water absorption amount (g / g) = (a - b) / b a: Weight of the heat storage part after water absorption (g) b: Weight of the heat storage part before water absorption (when dry) (g)

[0035] The basis weight of the polymer material 42 in the heat storage part 14 containing the fiber material 41 and the polymer material 42 is preferably 0.001 g / cm 2 or more and 0.1 g / cm 2 or less, more preferably 0.005 g / cm 2 or more and 0.05 g / cm 2 or less.

[0036] The foot warmer 1 of the present embodiment preferably includes holding means 2 capable of holding the state in which the foot warmer 1 is worn on the foot. The holding means 2 of the present embodiment is an adhesive tape 21 provided on the non-foot-facing surface (the second sheet 13 in the present embodiment) of the foot warmer 1 (see FIG. 4). This adhesive tape 21 is arranged around the foot warmer 1 in a state of being folded along the width direction Y. In the present embodiment, the adhesive tape 21 is wound around the ankle of the foot warmer 1 in the worn state to restrict the foot warmer 1 from unfolding. That is, the foot warmer 1 is held in a state of being folded in two in the longitudinal direction X and maintained in a state of covering the surface of the foot [see FIGS. 3(b) and 5].

[0037] The material used to form the fastening tape 21 is not particularly limited and may be a cloth tape made of woven or non-woven fabric, or a film tape made of synthetic resin, etc. From the viewpoint of improving ease of handling when wrapping it around the foot warmer 1, it is preferable that the fastening tape 21 is stretchable. In this case, the fastening tape 21 is stretched by pulling the tape 21 and then wrapped around the foot warmer 1 in its worn state. Rubber tape can be used as such a fastening tape 21.

[0038] The foot warmer 1 may also be equipped with a string that can be wrapped around the foot warmer 1 instead of the fastening tape 21. If the foot warmer 1 is equipped with the fastening tape 21 or the string, the fastening tape or string may maintain its wrapped state by tying itself, or it may be equipped with a restraining member to maintain the wrapped state. As the restraining member, adhesive tape, mechanical hook and loop fasteners, cord stoppers, buckles, suction cups, reels with built-in winding springs, etc., can be used. The cord stoppers, buckles, and suction cups fasten the ends of the fastening tape together or the ends of the string together, and the foot warmer 1 can be made to fit more snugly against the foot by adjusting the length when fastening.

[0039] The fastening tape 21 of this embodiment has a fixing portion that is fixed to the non-foot-facing surface of the foot warmer 1 and a free portion that is not fixed to the foot warmer 1, and the tip of the free portion has a free portion side fixing portion (not shown) for fixing to any part of the fastening tape 21. The free portion side fixing portion may be formed of adhesive tape. Alternatively, the free portion side fixing portion may be a male member of a mechanical hook-and-loop fastener that engages with a female member provided on a part of the fastening tape 21 other than the free portion side fixing portion. The male member is a surface member on which hook members consisting of hook-shaped protrusions are arranged on one surface. The female member is a surface member on which loop material consisting of pile-shaped protrusions is arranged on one surface. The male member of a mechanical hook-and-loop fastener has a configuration in which a large number of hook material is arranged on the surface of a base material made of resin film, woven fabric, nonwoven fabric, etc. For the female member of a mechanical hook-and-loop fastener, a sheet member on which loop portions or mesh portions are fixed to a base material, or a nonwoven fabric with good engagement can be used. A concrete example of such a mechanical hook-and-loop fastener is Velcro®. If the fixing portion on the free portion side is a male member, a female member is provided in addition to the tip of the free portion of the fastening tape 21. Conversely, the fixing portion on the free portion side may be a female member. In this case, a male member is provided in addition to the tip of the free portion of the fastening tape 21.

[0040] The foot warmer 1 and its components of the present invention are not limited to the embodiments shown in Figures 1 to 5. Another embodiment of the foot warmer 1 and its components according to the present invention will be described below. In the following, the components of the other embodiment will be described primarily in terms of their differences from those of the embodiments shown in Figures 1 to 5, while similar components will be denoted by the same reference numerals and their descriptions will be omitted. For components not specifically described, the descriptions of the embodiments shown in Figures 1 to 5 will be applied as appropriate.

[0041] The retaining means 2 provided by the foot warmer is not limited to the fastening tape described above. The foot warmer 1A shown in Figure 6(a) includes an engaging portion 23 and an engaged portion 24 provided on the side facing the foot as the retaining means 2. More specifically, the engaging portion 23 and the engaged portion 24 are provided on the foot-facing side of the side flap portion SF. The engaging portion 23 and the engaged portion 24 in this embodiment are the male and female members of the mechanical hook-and-loop fastener described above, and are able to engage with each other. In this embodiment, when the foot warmer 1A is folded along the width direction Y, that is, folded in half along the longitudinal direction X, the engaging portion 23 and the engaged portion 24 overlap and engage with each other, maintaining the folded state (see Figure 6(b)). From the viewpoint of making it easier to put on, it is preferable that the foot warmer 1A has the engaging portion 23 positioned on the dorsal portion 1t and the engaged portion 24 positioned on the sole portion 1b. The foot warmer 1A of this embodiment can be unfolded by releasing the engagement between the engaging portion 23 and the engaged portion 24.

[0042] The engaging portion 23 and the engaged portion 24 are a combination of members that can be integrated physically or magnetically. As such engaging portion 23 and engaged portion 24, snap buttons composed of a female hook and a male hook, fasteners composed of a hook or toggle and a ring, zippers, magnets, etc., can be used.

[0043] The present invention is not limited to the embodiments described above and can be modified as appropriate. For example, the foot warmer 1 may have a bag-shaped foot compartment for inserting and accommodating the foot before use. For example, the foot warmer 1 may be in the shape of a slipper. Furthermore, the foot warmer 1 may not be bag-shaped before use. "Non-bag-shaped" means that it does not have an opening and a storage space (internal space) that is in communication with the opening. Furthermore, the foot warmer does not have to include the three-dimensional cuffs 16, 16 and / or the side cuffs 15a. If the three-dimensional cuffs are not included, the foot warmer may, for example, include engaging portions 23 and engaged portions 24 provided on the sides of the first sheet that forms the foot-facing surface. [Examples]

[0044] [Examples] A foot warmer having substantially the same configuration as the foot warmers shown in Figures 1 and 2 was created and designated as the foot warmer of the embodiment. A liquid-permeable nonwoven fabric sheet was used as the first sheet, and a liquid-impermeable synthetic resin film sheet was used as the second sheet. The heat storage section consisted of a heat storage core composed of a fibrous material and a polymer material, covered with a core wrap sheet made of a liquid-permeable sheet material. The mass ratio of the fibrous material to the polymer material was 2. After supplying 300g of 50°C warm water to the foot warmer of the obtained embodiment from the first sheet side, the foot warmer was attached and secured to one foot of the subject so that the entire foot was covered, and warming was performed for 10 minutes. [Reference example] As an example of a conventional foot bath, approximately 6 liters of 40°C warm water were placed in a container measuring 40 cm long and 30 cm wide. One foot was then immersed up to the ankle and heated for 10 minutes.

[0045] 〔evaluation〕 In the example, a temperature logger (LT-8A, manufactured by Gram Co., Ltd.) was placed at the tip of the second toe to record changes in skin temperature during heating. In addition, a laser blood flow meter (FLO-C1, manufactured by Omega Wave Co., Ltd.) was placed at the tip of the second toe to record changes in skin blood flow to the toes during heating. In the reference example, the feet were withdrawn from the warm water every minute, and skin temperature and blood flow were measured in the same manner. 〔result〕 Figure 7(a) shows a graph illustrating the change in skin temperature, and Figure 7(b) shows a graph illustrating the change in blood flow. As shown in Figure 7, the foot warmer of the example provides a warming effect similar to a foot bath by immersing the feet in warm water. Furthermore, when multiple subjects were given the same foot warmer to warm their feet, the results showed that the foot warmer according to the present invention provided a sensation similar to a foot bath. [Explanation of Symbols]

[0046] 1 Foot warming device 1b Sole placement part 1t Dorsal foot placement part 2 Holding means 10 Heat storage unit 12 First sheet 13. Second seat 14 Heat storage section 16. Three-dimensional cuff 40 Heat Storage Cores 41 Textile materials 42 Polymer materials 43 Core Wrap Sheet

Claims

1. A foot warmer comprising a first sheet, a second sheet, and a heat storage unit disposed between the two sheets that absorbs energy supplied from the outside and stores heat, The first sheet is permeable to liquid, and the second sheet is poorly permeable to liquid. A foot warmer that is used by being worn on the feet after supplying hot water to the heat storage unit, or after supplying water to the heat storage unit and heating the water with electromagnetic waves.

2. The foot warmer according to claim 1, wherein the heat storage section contains a polymer material capable of generating a hydrogel by absorbing water, or an inorganic material having heat storage properties.

3. The heat storage section contains a polymer material capable of generating a hydrogel by absorbing water. The foot warmer according to claim 2, wherein the polymer material absorbs hot water supplied from the outside and stores heat.

4. The foot warmer according to claim 3, wherein the polymer material is held in place by the fiber material.

5. The foot warmer according to claim 4, which is used by supplying 50 mL to 800 mL of hot water to the heat storage unit.

6. The foot warmer according to any one of claims 1 to 5, wherein the foot warmer is equipped with a holding means capable of maintaining the foot warmer in a state of being attached to the foot.

7. Instructions for using a foot warmer, The aforementioned foot warming device is It comprises a first sheet, a second sheet, and a heat storage unit positioned between the two sheets that absorbs energy supplied from the outside and stores heat. The first sheet is permeable to liquid, and the second sheet is poorly permeable to liquid. A method for using a foot warmer, comprising supplying hot water to the heat storage unit, or supplying water to the heat storage unit and heating the water with electromagnetic waves, and then attaching the foot warmer to the foot.

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