Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Thermal applicators
Reexamination Certificate
1999-08-11
2001-07-24
Dvorak, Linda C. M. (Department: 3739)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Thermal applicators
C607S114000, C607S108000
Reexamination Certificate
active
06264681
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a method of manufacturing a foot warming exothermic device and the foot warming exothermic device. More particularly, the invention relates to a method of manufacturing a foot warming exothermic device which can easily produce an ultrathin foot warming exothermic device at low cost by placing a fluid exothermic composition on a wrapper at high speed, can securely fix a portion or the whole of the exothermic composition in the wrapper and prevent movement thereof, and can well conform to the user's foot configuration and efficiently warm a desired site of the foot when it is applied to the site, and to the foot warming exothermic device.
(2) Description of the Related Art
In recent years, exothermic devices of the type known as disposable body warmers have been widely used such that the exothermic device includes an exothermic composition enclosed in a flat pouch comprised of a gas permeable or gas-tight thin sheet base material and a gas permeable thin sheet covering material.
It is also common to use an exothermic device having an adhesive layer attached to one side of a pouch of the above noted type such that the exothermic device can be pasted directly or through underwear to the skin of a living body. Further, it has been proposed to utilize as a hot compress an adhesive layer with a wet pack medication incorporated or carried therein, or as a medication-containing layer with a skin absorbable medication incorporated or carried therein (see Japanese Patent Application published specification No. 2-149272).
As an old saying goes, “cooled head and warmed feet”, it has been believed that warming feet is a key to good health. With widespread use of such exothermic devices, therefore, foot warming exothermic devices for warming the sole of the foot have now become commercially available. Various foot warming exothermic devices of this type have been proposed including, for example, those disclosed in Japanese Patent Application published specifications Nos. 2-154762, 2-172460, 5-115310, Japanese Utility Model Applications published Nos. 6-21616 and 5-84317, and Japanese Patent Application published No. 5-176951.
In manufacturing such a foot warming endothermic device it is general practice to place an exothermic composition of powder form with some water content on a predetermined site in a base material and then cover the same with a gas permeable covering material. Thereafter, the base material and a peripheral edge portion of the covering material are sealingly bonded by heat sealing or with a hot melt adhesive over and along the entire peripheral edge portion.
Such a foot warming exothermic device of the prior art includes an exothermic composition containing, in traditionally appropriate proportions, a metal powder, such as iron powder, and water, and in addition an activated carbon for accelerating heat generation, a metal chloride for fracturing an oxide film on the surface of the metal powder and continuously generating an exothermic reaction,and a water retainer for preventing a sticky effect of the composition. The exothermic composition is in the form of a water-containing powder and is placed on a base material.
In the case where the exothermic composition, with all its ingredients mixed together in an appropriate blend ratio as above noted, is placed on the base material, the trouble is that after the blending of the ingredients into the exothermic composition and before the foot warming exothermic device is enclosed in an outer pouch, an exothermic reaction occurs which results in a loss of exothermic energy and a quality degradation of the exothermic composition. Furthermore, a reaction product resulting from the exothermic reaction involves various harmful effects, such as decreased yield, handling inconvenience, complicated maintenance-related problems, limitations affecting machine operation time as well as operator working hours, and difficulties involved in dealing with coagulated matter.
While the exothermic composition is provided through its water content with a wetting characteristic, the proportion of the water content is so low as to be suitable for an exothermic reaction, so that the exothermic composition assumes a powder form and has only poor fluidity. This poses a problem that it is extremely difficult to allow the composition to be uniformly distributed within a predetermined area on the base material through mere placement of the same in position. In view of this fact, it is common practice to equalize the distribution of the exothermic composition to some extent by means of a roller or the like during the process of covering the composition with a covering material and sealing the same. With such a method, however, the distribution of the exothermic composition tends to become inclined toward the source of pouch material. In order to increase the proportion of the exothermic composition distributed in the direction of pouch material feed, it is necessary to increase the height of a chamber defined within the pouch, thereby making it possible to eliminate any offset in the distribution of the exothermic composition as by manual shaking at the time of use.
Where the foot warming exothermic device becomes thicker in its entirety, the device feels rough and has poor hand. Moreover, the device has inferior flexibility so that it is unable to well conform to any complex surface irregularity at an application site and/or any curved surface of a small curvature. The thickness increase also results in a degradation in the extensibility or stretchability characteristic of the device, which in turn may result in a deformation due to the wearer's movement and a lower capability of conformance to such movement.
Furthermore, as already mentioned, foot warming exothermic devices of the prior art are such that although the exothermic composition is provided through its water content with wetting characteristics, the proportion of the water content is so low as to be suitable for an exothermic reaction, so that the exothermic composition assumes a powder form and has only poor fluidity. Therefore, it is extremely difficult to cause the exothermic composition to be uniformly distributed within a predetermined area on the base material, so that the thickness of the foot warming exothermic device is irregular. As such, when the device is used in such a condition that it is affixed to an application site, continued use of the device as affixed to the same application site may be a cause of a low temperature burn.
With foot warming exothermic devices of the prior art, it is impossible to completely prevent any possible displacement during the process of manufacture or in the course of transportation in the current status of the art.
Such foot warming exothermic device, prior to use, is transported for delivery in a condition such that it is packaged within an outer pouch (preservation pouch). In this stage of transport, the exothermic composition is movable within the exothermic device and, from the standpoint of safety maintenance, it has been taken as an important requirement that the device be kept uniform in thickness so as to enable the device to exhibit a constant temperature profile throughout its entirety. In the current practice, therefore, any such device in which the exothermic composition is non-uniformly distributed is returned as an off-standard product in the stage of distribution, or is replaced upon request from the user. Hence, it is very important to secure thickness uniformity with respect to the exothermic composition in the stage of transportation.
In Japanese Patent Application Laid-Open No. 62-347, a method for adhesively fixing an exothermic composition in position is proposed. In actual manufacturing operation, however, it is almost impossible to adhesively fix an exothermic composition in powder form within a pouch. Even if such adhesion could be done, the adhesion would be too weak to enable the composition to be well fixed in position, and
Dvorak Linda C. M.
Gregg Edwin E.
Greigg Ronald E.
Kabushiki Kaisha Genchi Kenkyusho
Ram Jocelyn
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