JPH01201253A - Sheet-shaped heating element - Google Patents

Abstract

PURPOSE:To improve the contact efficiency of a composition and an air and to prevent the calorific value from reducing by molding in a sheet shape the composition composed by mixing a fiber-shaped substance to at least an iron powder, an activated carbon, an electrolyte and water by paper-making. CONSTITUTION:A fiber-shaped substance is suspended in water, beated lightly with a refiner, etc., the iron powder, activated carbon, electrolyte, water-holding agent, additives, etc., are added to this, stirred, suspended, filtered through a paper making machine with a wire, and after dewatering by suction, they are sandwiched with a canvas, etc., further, the dewatering is executed with the press, molded to thickness of about 0.2-10mm and thus, the sheet-shaped heating element of the moisture content 5-65wt.% is obtained. Both surfaces of the sheet-shaped heating element 1 are covered with a permeability film 2, and a peripheral part 3 is bonded by adhesive or sealed by the thermal fusion. Since the heating element does not generate the bias due to the movement of a heating composition like the conventional one, a stable heating performance is obtained and at the time of installation in human body, the sense of incompatibility does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sheet-like heating element, and more particularly to Il!
The present invention relates to a sheet-like heating element formed from a composition containing powdered fibrous proboscis, activated carbon, an electrolyte, and water.

[Conventional technology]

Exothermic compositions have been known that generate chemical reactions by bringing them into contact with oxygen in the air and utilize the heat of the reaction. These include those mixed with electrolytes and water, and those mixed with metal sulfides or polysulfides and carbon materials.

These heat-generating compositions are made of a bag made of a breathable film that can supply the air necessary to obtain effective heat-generating performance as a heat generating element, or a film that is made breathable by providing holes in a non-breathable film. It is used as a heating element by being stored in a container such as a refrigerator, and is used as a heating device.

These heating elements are stored sealed in an oxygen-impermeable outer bag or the like and cut off from contact with the outside air until they are used.

[Problem to be solved by the invention]

However, while conventional heating elements have the advantage of being easy to use, they also have drawbacks.

In other words, when these heating elements are used to heat or keep warm the human body, mechanical equipment, parts, etc., the heat-generating composition flows downwards of the bag due to gravity not only when subjected to movement or vibration, but also when stationary. In addition to causing a sense of discomfort due to the change in shape, the heating characteristics themselves also change, resulting in a reduction in the amount of heat generated.

Furthermore, since the shape, size, etc. of these heating elements are determined at the time of manufacture, there is also the disadvantage that they cannot be changed depending on the intended use during use.

[Means and actions for solving problems]

As a result of intensive research to improve these shortcomings, the inventors of the present invention focused on the sheet-like binding method used in paper making.
Complete this invention.

That is, the present invention is a sheet-like heating element characterized in that it is formed by forming a composition in which a fibrous material is mixed into at least iron powder, activated carbon, electrolyte, and water into a sheet shape by papermaking.

The fibrous materials used in the present invention include iron powder, activated carbon,
Gaps are provided to retain electrolyte, water, etc., and to improve the efficiency of contact between the composition and air.

As the fibrous material, natural fibers and synthetic fibers can be used, and there are no particular restrictions on their dimensions, but usually 0.3
A length of 0.2 to 25 m+m is used.

Natural fiber materials include, for example, pulp, viscose rayon, cotton, linen, wool and asbestos; synthetic fiber materials include, for example, polyacrylic, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl acetate. Fibers such as copolymers, polyesters, polyamides and polyvinyl alcohols and mixtures thereof are used. Among these, fibers such as pulp, cotton, polyethylene, polypropylene, and polyacrylic are generally preferred.

There are no particular restrictions on the type of iron powder used in the present invention, but
Examples include reduced iron, atomized iron, and electrolytic iron.

The particle size is usually 60 mesh or less, and preferably contains 50% or more of particles of 200 mesh or less. - Activated carbons are used as reaction aids and water retention agents, such as charcoal, wood powder charcoal, charcoal, peat and lignite. The particle size of activated carbon is usually 60 mesh or less,
Preferably, it contains 50% or more of 14Q+++esh or less.

As the electrolyte, inorganic salts are usually used, such as sulfates, carbonates, chlorides, and hydroxides of alkali metals, alkaline earth metals, and heavy metals. Among these, chlorides are preferred, such as NaCl, KCI, C
aCl2. MgCl2. Examples include FeCl2 and FeCl3.

In the present invention, zeolite, diatomaceous earth, perlite, vermiculite, water-absorbing resin, etc. may be further mixed with the fibrous material, iron powder, activated carbon, electrolyte, and water as a water-retaining agent. Additives such as sizing agents, fillers, retention aids, coloring agents, and paper strength enhancers may be used in combination.

The sheet-shaped heating element of the present invention is made into a sheet by papermaking, but usually, fibrous substances, activated carbon, electrolytes, and other additives are mixed and suspended in water, and the suspension is made into a sheet. It is filtered and further dehydrated until the moisture content becomes 65 wt% or less, preferably 50 wt% or less, and then formed into a sheet.

The proportion of solids that are not soluble in water in a suspension is usually between 0.2 and 2, based on the total weight of the suspension based on the sum of fibrous material, iron powder, activated carbon, electrolyte and water. The content is 20 wt%, preferably 1 to 15 wt%.

In addition, the ratio of each component is 0.02 to 4 wt% for the fibrous material, preferably 0.2 to 4 wt%, and usually 0.02 to 4 wt% for the iron powder, based on the total weight of the suspension. .1 to 20 wt%, preferably 0.5 to 10 wt%,
Activated carbon is about 0.01 to 12 wt%, preferably about 0.1 to 5 wt%, and electrolyte is usually used by dissolving it in water, but it is about 0.2 to 25 w in terms of solid matter.
t%, preferably about 1 to 15 wt%.

Next, an example of a method for manufacturing a sheet-like heating element will be specifically described.

Fibrous substances are suspended in water, beaten slightly with a refiner, etc., iron powder, activated carbon, electrolytes, water retention agents, additives, etc. are added to this, stirred and suspended, and passed through a paper machine. , filtered with a wire, dehydrated by suction, and further dehydrated by sandwiching it between canvases, etc., to a thickness of 0.2 to 101111.
By molding preferably to a thickness of about 2 to 8 mm, a sheet-like heating element having a moisture content of 5 to 65 wt%, preferably 20 to 50 wt% can be obtained.

During this manufacturing process, it is preferable to carry out the process in an inert gas atmosphere such as nitrogen or argon in order to prevent the iron powder from coming into contact with oxygen in the air and being oxidized.

The sheet-like heating element thus obtained can be used as it is.
Alternatively, it can be cut into desired sizes and used for heating and keeping warm the human body, machinery, equipment, parts, food, etc.

In addition, in order to prevent contamination of objects to be kept warm due to migration of components of this sheet-shaped heating element, this sheet-shaped heating element may be covered with a breathable film or covered with synthetic resin, if necessary. It is also possible to form an air-permeable film with paint or the like, or to add a fibrous material to the surface of the heating element.

FIGS. 1 and 2 are cross-sectional views illustrating the state of these coatings.

In FIG. 1, both sides of a sheet-like heating element 1 are covered with an air-permeable film 2, and the peripheral part 3 is sealed by adhesive bonding or thermal fusion. Note that the breathable film may be provided on only one side, and in this case, a non-breathable film or the like is used on the other side.

Examples of breathable films include paper, non-woven fabric, microporous membranes, these films laminated with perforated plastic films, or laminated paper or non-woven fabrics with non-porous plastic films, which can be used with needles, lasers, etc. A type with fine holes is used.

In FIG. 2, an adhesive layer 4 is partially provided on the surface of a sheet-like heating element 1, and a breathable film 2 is bonded to this.

The material for these coverings may be any material as long as it has the air permeability necessary for heat generation and can prevent the object to be kept warm from being contaminated by migration of the components of the sheet-like heating element.

〔Example〕

Example 1 Under nitrogen gas atmosphere, 3 g of pulp, particle size of 200 m
20g of reduced iron powder containing 80% of less than esh, 7.5g of activated carbon, and 50g of water in which 116g of NaC was dissolved.
0- and stirred to suspend. This suspension has a diameter of 1
The mixture was poured into a Buchner funnel lined with 10 mm filter paper and filtered by suction to obtain a sheet with a water content of 45 wt%. This material was centrifugally dehydrated to form a sheet-like heating element with a moisture content of 40 wt%.

The thickness of the obtained sheet-like heating element was 5IIIllI,
This product was sealed in an oxygen-impermeable outer bag.

Example 2 The sheet-like heating element obtained in Example 1 was taken out of the outer bag, cut into 5 x 5 cm pieces, and heated on Styrofoam in air at a room temperature of 20°C and a relative humidity of 65%.
As shown in the figure, the temperature of the heating element reached 80° C. or higher after 5 minutes, indicating that the heating element had sufficient heat generation performance for practical use.

Examples 3 to 5 As shown in Table 1, three types of sheet-like heating elements were manufactured in the same manner as in Example 1 except that the proportion of activated carbon was changed.

Cut each of these heating elements into 5x5c++ pieces, and
When heat was generated on the foamed polystyrene in air at a temperature of 65% relative humidity, the heat generation performance as shown in FIG. 4 was obtained.

Table 1 Examples 6 to 8 Three types of sheet-like heating elements obtained in the same manner as in Example 3 were each cut to 7.5 x 7.5 cm, and 330 ventilation holes with a diameter of 0.3 mm were formed on one side. A sheet-like heating element having a shape similar to that shown in Fig. 1 is obtained by overlapping and covering the plastic film with a non-porous non-porous plastic film on the other side, and sealing the periphery by heat fusion. I got it.

When this heating element was sandwiched between cushions in air at a room temperature of 20°C and a relative humidity of 65% to generate heat, a practically sufficient heat generation performance was obtained as shown in FIG. Furthermore, no contamination of the cushion due to transfer of components from the heating element was observed.

Example 9 A sheet-like heating element obtained in the same manner as in Example 1 was heated to 7.5
After cutting it into 7.5cm x 7.5cm pieces, apply vinyl acetate adhesive to both sides with a diameter of 4mm and dots at 10mm intervals.
On top of that, Gurley type air permeability (Gurley type air permeability test, J
(according to IS-P8117) is 1400 sec / 10
A sheet-like heating element similar to that shown in FIG. 2 was obtained by laminating porous membrane sheets of 0 mQ.

When this heating element was heated on a polystyrene foam in air at a room temperature of 20° C. and a relative humidity of 65%, it had a practically sufficient heating performance as shown in FIG.

〔Effect of the invention〕

The sheet-like heating element of the present invention has the following characteristics: (1) Unlike conventional heating elements, the heating composition does not shift due to movement, so stable heating performance is obtained;
It does not cause any discomfort when worn on the human body.

■Since it is sheet-like and flexible, it can be fitted tightly when heating equipment.

■Since it is shaped into a sheet, the powder will not scatter, and it can be cut to suit the shape and size of the object to be kept warm.

It has many excellent features such as:

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are respectively sectional views of the sheet-like heating element of the present invention, and FIGS. 3 to 6 are diagrams showing the heat generation performance, respectively. The drawing numbers are as follows. 1. Sheet heating element 2. Film 3, peripheral area
4. Adhesive layer patent applicant Nippon Bionics Co., Ltd. Division 1 “”
r+Tl(h7')

Claims (1)

[Claims] 1. A sheet-like heating element, characterized in that it is formed into a sheet by papermaking from a composition comprising a fibrous substance mixed with at least iron powder, activated carbon, an electrolyte, and water.