TECHNICAL FIELD

The present invention relates to a heat-generating device. More specifically, the present invention relates to a heat-generating device with which a warm sensation is persistently perceived, and which can effectively exert a heating effect.

BACKGROUND ART

Conventionally, heat-generating devices that use an exothermic composition that generates heat upon contact with air have been extensively used not only as warming devices for protection from the cold and the like, but also as therapeutic devices and the like for promoting blood circulation, relieving pain, and the like. Disposable body warmers, for example, which have excellent portability, and are inexpensive, are suitably used as warming devices, therapeutic devices, and the like. Moreover, conventionally, heat-generating devices each having an adhesive layer, which are designed to be readily fixable to skin, have also been extensively used.

Furthermore, heat-generating devices having adhesive layers containing active ingredients for imparting various functionalities to the heat-generating devices have been conventionally proposed. Patent Literature 1, for example, discloses a heat-generating device having an adhesive layer containing an active ingredient. Patent Literature 1 also discloses that a warming component can be used as an active ingredient contained in the adhesive layer. Such a heat-generating device including an adhesive layer containing a warming agent is expected to have an improved heating effect.

In recent years, there has been an increasing consumer demand for improved functionalities of heat-generating devices, and there is an urgent need for the development of a heat-generating device that has improved persistence of a perceived warm sensation, and can exert a heating effect more effectively.

CITATION LIST

Patent Literature 1: JP 2014-8288 A

SUMMARY OF INVENTION

Technical Problem

An object of the present invention is to provide a heat-generating device with which a warm sensation is persistently perceived, and which can effectively exert a heating effect.

Solution to Problem

The inventor of the present invention conducted extensive research to solve the aforementioned problem, and found that a heat-generating device that is used by being attached to skin, which comprises the following features (1) to (3), has improved persistence of a perceived warm sensation, and can exert a markedly high heating effect:

(1) A packaging material constituting a skin attachment surface of a housing is formed of a laminated sheet in which at least a moisture absorption layer that absorbs moisture and a moisture barrier layer that blocks penetration of moisture are laminated in this order from the adhesive layer;

(2) An adhesive layer is partially provided on a surface of the moisture absorption layer; and

(3) A warming agent that allows an enhanced warm sensation to be perceived in the presence of moisture is contained in at least one of the adhesive layer and the moisture absorption layer.

The present invention has been completed by conducting further research based on the findings. In summary, the present invention provides aspects of invention as itemized below.

Item 1. A heat-generating device that is used by being attached to skin, comprising:

a heat-generating portion that generates heat to be delivered to skin;

a housing that contains the heat-generating portion, and has a skin attachment surface that is to be attached to the skin; and

an adhesive layer provided on the skin attachment surface of the housing,

wherein a packaging material constituting the skin attachment surface of the housing is formed of a laminated sheet in which at least a moisture absorption layer that absorbs moisture and a moisture barrier layer that blocks penetration of moisture are laminated in this order from the adhesive layer,

the adhesive layer is partially provided on a surface of the moisture absorption layer, and

a warming agent that allows an enhanced warm sensation to be perceived in the presence of moisture is contained in at least one of the adhesive layer and the moisture absorption layer.

Item 2. The heat-generating device according to item 1, wherein, on the surface of the moisture absorption layer, an area ratio of an adhesive layer formation region where the adhesive layer is formed relative to a moisture absorption layer exposure region where the moisture absorption layer is exposed is 100:5-2000.

Item 3. The heat-generating device according to item 1 or 2, wherein, on the surface of the moisture absorption layer, the moisture absorption layer exposure region where the moisture absorption layer is exposed communicates with an edge of the moisture absorption layer.

Item 4. The heat-generating device according to any one of items 1 to 3, wherein the packaging material constituting the skin attachment surface of the housing has a barrier function to block penetration of the warming agent.

Item 5. The heat-generating device according to item 4, wherein the moisture barrier layer contains a resin layer formed of polyethylene terephthalate, polyacrylonitrile, or an ethylene-vinyl alcohol copolymer; a vapor-deposited film; and/or a metal foil film.

Item 6. The heat-generating device according to any one of items 1 to 5, wherein the moisture absorption layer is a fibrous sheet.

Item 7. The heat-generating device according to any one of items 1 to 6, wherein the warming agent is contained in the adhesive layer.

Item 8. The heat-generating device according to any one of items 1 to 7, wherein the warming agent is at least one selected from the group consisting of capsaicin, nonanoic acid vanillylamide, sage, caffeine, tocopherol nicotinate, nicotinic acid benzyl ester, vanillyl ethyl ether, vanillyl propyl ether, vanillyl butyl ether, vanillyl pentyl ether, vanillyl hexyl ether, vanillyl butyl ether acetate, gingerol,Capsicum annuumextract, and ginger extract.

Item 9. The heat-generating device according to any one of items 1 to 8, wherein the heat-generating portion is an exothermic composition that generates heat upon contact with oxygen, and the housing is at least partially air-permeable.

Advantageous Effects of Invention

The heat-generating device of the present invention allows a user to persistently perceive a warm sensation imparted by the heat-generating portion and a warm sensation imparted by the warming agent. This persistence of the warm sensation depends on the unique structure of the heat-generating device of the present invention, and is believed to be achieved by repetition of (1) to (4): (1) sweat is produced from the skin due to the warm sensation imparted by the heat-generating portion; (2) the sweat is absorbed by the moisture absorption layer; (3) the warm sensation imparted by the warming agent is enhanced via the absorbed sweat; and (4) when the user becomes perceptually used to the warm sensation, the user predominantly perceives the warm sensation imparted by the heat-generating portion.

The heat-generating device of the present invention allows a user to persistently perceive a warm sensation imparted by the heat-generating portion and a warm sensation imparted by the warming agent, and thus, can be suitably used as therapeutic devices for promoting blood circulation, reducing stiff shoulders, relieving pain, and the like. Furthermore, the heat-generating device of the present invention can suppress stickiness due to sweat during use, and can prevent removal from the skin, and thus, can provide an excellent feel in use.

