Foot warming device and method of using the foot warming device

Abstract

To provide a foot warmer and a method for using the foot warmer that exhibits excellent adhesion to the surface and can maintain good contact with the surface of the foot. [Solution] The foot warmer 1 of the present invention comprises a first sheet, a second sheet 13, and a heat storage section 14 positioned between the two sheets and absorbing energy supplied from the outside to store heat. Before use, the foot warmer 1 is not bag-shaped, has deformability that can conform to the shape of the foot, and is equipped with a holding means 2 that can maintain the state in which the foot warmer 1 is attached to the foot. In plan view, the foot warmer 1 preferably has a shape that is elongated in one direction, having a longitudinal direction X and a width direction Y perpendicular to the longitudinal direction X. The holding means 2 preferably holds the foot warmer 1 in a folded state along the width direction Y.

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] Articles are known that are applied to the surface of the body to provide warming or cleaning effects to the target area. For example, Patent Document 1 discloses footwear comprising a sole body provided with a housing section, and a heating element housed in the housing section and formed to a size that substantially corresponds to a part of the sole of the foot. The applicant previously proposed a foot bath steam heating device comprising a bag-shaped foot compartment having a space for accommodating feet, a steam generating unit containing an oxidizable metal, water, an electrolyte, and a reaction accelerator provided in the foot compartment, and a narrow, strip-shaped fixing device attached near the opening of the foot compartment (Patent Document 2).

[0003] Patent Document 3 discloses a water-repellent foot bath bag in which a nonwoven or woven fabric is set, and a predetermined amount of mixed liquid and feet are contained. Patent Document 4 discloses a steam cloth comprising a first towel containing steam at a predetermined temperature and a second towel wrapped in the first towel. Patent Document 5 discloses a body cleansing sheet comprising two surface layers made of nonwoven fabric and a water-absorbent polymer layer disposed between these surface layers, wherein the water-absorbent polymer layer contains a water-absorbent polymer in a fibrous material or is formed by dispersing and solidifying a water-absorbent polymer on a fibrous material. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2001-275707 [Patent Document 2] Japanese Patent Publication No. 2008-86688 [Patent Document 3] Japanese Patent Publication No. 2015-196031 [Patent Document 4] Japanese Patent Publication No. 2016-39848 [Patent Document 5] International Publication No. 2018 / 003885 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, the feet, being a peripheral area, are prone to reduced blood flow and are easily affected by cold. Warming the feet to improve blood flow is effective in lowering the body's core temperature and promoting sleep. However, the articles disclosed in Patent Documents 1, 3, 4, and 5 are difficult to maintain stably when applied to the surface of the feet, making it difficult to obtain a sufficient warming effect. Furthermore, the steam heating device for foot baths disclosed in Patent Document 2 had room for improvement in terms of adhesion to the surface of the feet.

[0006] The present invention relates to a foot warmer that has excellent adhesion to the surface of the foot and can maintain a good state of adhesion to the surface of the foot, and to a method of using the foot warmer. [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 foot warmer is not bag-shaped before use, has deformability that can conform to the outer shape of the foot, and is equipped with a retaining means that can maintain the state in which the foot warmer is attached 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. As one embodiment, it is preferable that the foot warmer is non-bag-shaped before use and has deformability capable of following the outer shape of the foot. As one embodiment, it is preferable that the usage method is to use the foot warmer while holding it in a mounted state where the foot warmer is mounted on the foot by holding means provided in the foot warmer.

Advantages of the Invention

[0009] According to the foot warmer of the present invention and the usage method of the foot warmer, the adhesion to the foot surface is excellent, and the state of being adhered to the foot surface can be maintained well.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1 is a view showing one embodiment of the foot warmer of the present invention, and is a plan view schematically showing the side facing the foot in the maximum extended state of the foot warmer. [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 a method of mounting the foot warmer of FIG. 1. [Figure 4] FIG. 4 is a view showing one embodiment of the holding means according to the present invention, and is a perspective view showing the mounted state of the foot warmer held by 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 embodiment of the holding means according to the present invention, and are perspective views showing a method of mounting the foot warmer provided with the holding means.

Embodiments for Carrying Out the Invention

[0011] The present invention is a foot warmer having a first sheet, a second sheet, and a heat storage portion disposed between both sheets and absorbing externally supplied energy to store heat. The foot warmer is non-bag-shaped before use, has deformability that can follow the outer shape of the foot, and includes holding means capable of holding the state in which the foot warmer is worn on the foot. It relates to a foot warmer. 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 each dimension 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 the present embodiment is a wearing tool 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 the present 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 the present embodiment has a shape that is long in one direction in a plan view in the unfolded state, and has an outer shape that is line-symmetric with respect to a virtual straight line CL that bisects the entire length in the width direction Y and extends in the longitudinal direction X (see FIG. 1). More specifically, the foot warmer 1 of the present 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 design dimensions, that is, the dimensions when the influence of the elastic member is completely excluded, is also referred to as the "unfolded extended state". FIG. 1 shows the foot warmer 1 in the unfolded extended state.

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

[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] 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 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.

[0017] 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.

[0018] 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.

[0019] 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 has a side cuff elastic member 15a that extends in the longitudinal direction X between the first sheet 12 and the second sheet 13. The side cuff elastic member 15a is fixed between the first sheet 12 and the second sheet 13 with an adhesive or the like. In such a side flap portion SF, gathers extending in the longitudinal direction X are formed when the side cuff elastic member 15a contracts in the longitudinal direction X. 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.

[0020] 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 of this embodiment 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.

[0021] The heat storage section 14 of this embodiment includes a heat storage core 40 containing a heat storage material and a core wrap sheet 43 covering the heat storage core 40. Furthermore, the heat storage core 40 can appropriately use polymer materials and inorganic materials such as diatomaceous earth and ceramics as heat storage materials. In this example, the heat storage core 40 contains a polymer material 42 and a fiber material 41, which are heat storage materials. The polymer material 42 is capable of generating a hydrogel by absorbing water. With this polymer material 42, the heat storage core 40 can store heat by absorbing hot water supplied from the outside, or the water absorbed by the core 40 can generate heat by absorbing electromagnetic waves supplied from the outside, thereby storing 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 exhibiting an excellent heating effect. Examples of water-absorbing polymers that can be used include crosslinked polymers or copolymers of acrylic acid or alkali metal acrylates, crosslinked polyacrylic acid and its salts and polyacrylate graft polymers, crosslinked starch or carboxymethylated cellulose, crosslinked hydrolysis products of starch-acrylate graft copolymers, crosslinked vinyl alcohol-acrylate copolymers, crosslinked maleic anhydride-grafted polyvinyl alcohol, crosslinked isobutylene-maleic anhydride copolymers, saponified vinyl acetate-acrylic acid ester copolymers, 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.

[0022] In the heat storage core 40, 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 restricted, and a good wearing comfort can be maintained. The term "held" above means a configuration in which multiple 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.

[0023] 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.

[0024] 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 later.

[0025] From the viewpoint of exhibiting an excellent heating effect, the heat storage body 10 preferably has a first sheet 12 that is permeable to liquid and a second sheet 13 that is poorly permeable to liquid. With this configuration, water supplied from the first sheet 12 side to the heat storage body 10 can permeate the first sheet 12 and reach the heat storage section 14. In addition, the poorly permeable second sheet 13 can prevent the water supplied to the heat storage body 10 from leaking to the outside. As liquid-permeable sheets, single-layer or multi-layer nonwoven fabrics, perforated films, and the like can be used. Liquid permeability is a concept that includes liquid impermeability, encompassing properties such as complete density to liquids and water repellency. Examples of liquid-permeable sheets include moisture-permeable resin films, laminates of the resin film and nonwoven fabric, and water-repellent treated nonwoven fabrics.

[0026] 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.

[0027] The foot warmer 1 of this embodiment is non-bag-shaped before use, regardless of whether the heat storage section 14 is in a heat-storing state or not. "Non-bag-shaped" means that it does not have an opening and a storage space (internal space) communicating with the opening. Because the foot warmer 1 of this embodiment is non-bag-shaped, it does not have a storage space (internal space) and can be laid flat (unfolded).

[0028] The foot warmer 1 of this embodiment has deformability that can follow the shape of the foot. In other words, the foot warmer 1 is configured to be bend to conform to 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 storage 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 0.01 N / width 6 cm or more and 10 N / width 6 cm or less, more preferably 0.01 N / width 6 cm or more and 3 N / width 6 cm 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.

[0029] From the viewpoint of further improving conformability to the feet, the maximum thickness t of the heat storage body 10 (see Figure 2) is preferably 1 mm or more and 30 mm or less, more preferably 3 mm or more and 20 mm or less, and even more preferably 5 mm or more and 10 mm or less.

[0030] Figure 3 shows 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.

[0031] 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.

[0032] The foot warmer 1 of this embodiment is equipped with a holding means 2 capable of maintaining the foot warmer 1 in an attached state. The holding means 2 of this embodiment is a fastening tape 21 provided on the non-foot-facing surface of the foot warmer 1 (the second sheet 13 in this embodiment) (see Figure 4). This fastening tape 21 is arranged around the foot warmer 1 in a folded state along the width direction Y. In this embodiment, the fastening tape 21 is wrapped around the ankle of the attached foot warmer 1 to prevent the foot warmer 1 from unfolding. That is, the foot warmer 1 is maintained in a folded state along the longitudinal direction X, and the state of covering the surface of the foot is maintained (see Figures 3(b) and 5). In this way, the foot warmer 1 of this embodiment is used while being held in an attached state by the holding means 2.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The foot warmer 1 of this embodiment is deformable to conform to the shape of the foot, and its attachment to the foot is maintained by the holding means 2. For example, as shown in Figure 5, by making the entire heat-storing body 10 conform to the shape of the foot, the heat-storing body 10 can be made to adhere well to the surface of the foot, such as the sole or top of the foot. In addition, the holding means 2 can maintain the state in which the heat-storing body 10 adheres to the foot. With such a foot warmer 1, the surface of the foot can be continuously and effectively warmed by the heat of the heat-storing body 10 that adheres to the surface of the foot.

[0037] In this embodiment, the foot warmer 1 can be made to adhere well to the top of the foot and toes by the weight of the water absorbed by the polymer material 42 of the heat storage section 14. From the viewpoint of further improving this effect, the foot warmer 1 preferably has the following configuration. The heat storage part 14 preferably has an absorption amount per unit area of 0.05 mL / cm 2 or more and 6 mL / cm 2 or less, more preferably 0.5 mL / cm 2 or more and 3 mL / cm 2 or less, still more preferably 1 mL / cm 2 or more and 1.5 mL / cm 2 or less. The absorption amount per unit area is obtained by dividing the saturated water absorption amount of the heat storage part 14 by the area of the heat storage part 14 in plan view (saturated water absorption amount of heat storage part 14 / area of 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, and drained for 30 minutes, 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) In the heat storage part 14 containing the fiber material 41 and the polymer material 42, the basis weight of 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, from the viewpoint of exerting an excellent heating effect.

[0038] In the foot warmer 1 of the present embodiment, the heat storage part 14 includes the fiber material 41 and the polymer material 42. Instead of this, the heat storage part 14 may be composed only of a hydrogel in a state of absorbing water (hereinafter, also simply referred to as "hydrogel"). In such a form, since it contains water for heat storage, an operation of supplying water when using the foot warmer 1 is unnecessary, and heat storage of the heat storage part 14 is possible by exposing it to electromagnetic waves. The aforementioned hydrogel is obtained by allowing the polymer material 42 described above to absorb water. In the foot warmer 1, it is preferable that the heat storage section 14, which is composed solely of hydrogel, is placed between the liquid-impermeable first and second sheets 12 and 13. This configuration further suppresses leakage and evaporation of water from the hydrogel to the outside. From the viewpoint of further improving the adhesion of the heat storage body 10, even when the heat storage section 14 is composed solely of hydrogel, it is preferable that the amount of absorption per unit area of ​​the heat storage section 14 is within the range described above.

[0039] After heat storage, the heat storage section 14 gradually decreases in temperature over time. The foot warmer 1 of this embodiment can be unfolded by releasing the fastening tape 21 around the ankle. This allows the foot to be freed from the foot warmer 1. If the heat storage section 14 of the foot warmer 1 is composed solely of hydrogel, the heat storage section 14 can be restored to a heat-storing state by applying electromagnetic waves to it again. In other words, the foot warmer 1 can be used repeatedly.

[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. Furthermore, the embodiments described above may be combined. For example, the foot warmer 1 may be equipped with a combination of a fastening tape 21 and an engaging portion 23 and a engaged portion 24 as a holding means 2.

[0044] The foot warmer may also include an adhesive portion as a holding means 2, provided on the side facing the foot. In this case, when the foot warmer is folded in half along its longitudinal direction X, the adhesive portion is positioned on either the sole portion 1b or the dorsum portion 1t. The adhesive portion can be formed by applying a gel-like substance thickened with an adhesive or thickener to the side facing the foot of the foot warmer. It is also preferable that the adhesive portion is covered with a release sheet (not shown) made of film, nonwoven fabric, paper, etc., before use.

[0045] The foot warmer may also be provided with the aforementioned engaging portion 23 and engaged portion 24 at each end in the longitudinal direction X, or with the aforementioned adhesive portion at one end in the longitudinal direction X. In this case, the foot warmer is wrapped around the foot so that the longitudinal direction X follows the width of the foot, and the worn state is maintained by fixing the engaging portion 23 and engaged portion 24 at both ends in the longitudinal direction X, or by fixing the adhesive portion to any part of the foot warmer. Furthermore, the foot warmer does not have to include the three-dimensional cuffs 16, 16 and / or the side cuff elastic member 15a. If the three-dimensional cuffs are not included, the foot warmer may, for example, include engaging portion 23 and engaged portion 24 provided on the side of the first sheet that forms the foot-facing surface. [Explanation of symbols]

[0046] 1,1A 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 part 15a Side cuff elastic member 16. Three-dimensional cuff 16a Cuff elastic member 16b Cuff forming sheet 16d Non-erecting joint 16s standing section 21. Fastening tape 23 Engaging part 24 Engaged part 40 Heat Storage Cores 41 Textile materials 42 Polymer materials 43 Core Wrap Sheet X Longitudinal direction Y width direction

Claims

1. A foot warmer comprising 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 foot warmer is non-bag-shaped before use, has deformability that conforms to the shape of the foot, and is equipped with a retaining means that can maintain the state in which the foot warmer is attached to the foot.

2. In a plan view, it has a shape that is elongated in one direction, with a longitudinal direction and a width direction perpendicular to the longitudinal direction. The foot warmer according to claim 1, wherein the holding means holds the foot warmer in a folded state along the width direction.

3. In the aforementioned mounting state, the first sheet forms a foot-facing surface that faces the surface of the foot, and the second sheet forms a non-foot-facing surface that is opposite to the foot-facing surface. The foot warmer according to claim 2, wherein the retaining means is a fastening tape provided on the non-facing surface of the foot and is arranged around the bent foot warmer.

4. In the aforementioned mounting state, the first sheet forms a foot-facing surface that faces the surface of the foot, and the second sheet forms a non-foot-facing surface that is opposite to the foot-facing surface. The foot warmer according to claim 2, wherein the holding means is an engaging portion and an engaged portion provided on the side of the foot-facing surface, and the engaging portion and the engaged portion engage with each other in the bent state.

5. The heat storage section contains a polymer material capable of generating a hydrogel by absorbing water. The foot warmer according to claim 1 or 2, wherein the polymer material absorbs hot water supplied from the outside and stores heat.

6. The foot warmer according to claim 5, wherein the polymer material is held in place by the fiber material.

7. The foot warmer according to claim 6, wherein the first sheet is permeable to liquid and the second sheet is poorly permeable to liquid.

8. The heat storage section contains a hydrogel that has absorbed water. The foot warmer according to claim 1 or 2, wherein the water absorbed by the hydrogel absorbs electromagnetic waves applied from the outside, generates heat, and stores heat.

9. 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. Before use, it is not bag-shaped and has the deformability to conform to the outer shape of the foot. A method for using a foot warmer, comprising using the foot warmer to hold the foot warmer in an attached state by the holding means provided for the foot warmer.

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