JP2005319049A - Heating compact - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating compact showing a sign of a replacement time by quickly lowering a temperature from a heating maximum temperature to the heating end and giving superior actual warm sensation and hyperthermia effect by gradually increasing a heating temperature. <P>SOLUTION: This heating compact is formed by including electrolyte and water in a heating intermediate compact including oxidizable metal, water retaining agent, and fibrous materials. The ratio of the content of the oxidizable metal to that of the water retaining agent in the heating compact is 45:1-0.3:1 (weight ratio), the total content rate of the oxidizable metal to the water retaining agent in the heating compact is 50-98 wt.%, a temperature lowering speed in five minutes from a time of reaching the heating maximum temperature of the heating compact to heating end is 0.7-10 °C/5 min. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat-generating molded body that uses heat generated by an oxidation reaction between oxygen in air and an oxidizable metal.

  The present applicant has previously proposed a thin heat generating sheet described in Patent Document 1 below, which relates to a heat generating sheet using heat generated by an oxidation reaction between oxygen in the air and an oxidizable metal. The heat generating sheet has excellent heat generation characteristics as a heat generating element despite its extremely small thickness, and is excellent in productivity.

  By the way, depending on the use of such a heat generating sheet, the heat generation temperature gradually rises so that the actual temperature feeling and the thermal effect can be clearly understood, and at the end of heat generation, the temperature rapidly decreases, and the sign of replacement timing What would have been desired.

JP 2003-102761 A

  The present invention relates to an exothermic molded article excellent in the sense of actual temperature and the thermal effect when the temperature rapidly decreases from the maximum exothermic temperature to the end of the exotherm and becomes a sign of replacement time or the exothermic temperature gradually increases. .

  The present invention is an exothermic molded body in which an electrolyte and water are included in an exothermic intermediate molded body containing an oxidizable metal, a water retention agent and a fibrous material, and the oxidizable metal in the exothermic intermediate molded body and The ratio of the content of the water retention agent is 45: 1 to 0.3: 1 (weight ratio), and the total content of the oxidizable metal and the water retention agent in the exothermic intermediate molded body is 50 to The exothermic molded body is 98% by weight, and the temperature drop rate for 5 minutes from when the maximum heat generation temperature of the exothermic molded body reaches the end of heat generation is 0.7 to 10 ° C / 5 min.

  According to the present invention, the temperature rapidly decreases from the maximum heat generation temperature to the end of heat generation, and becomes a sign of replacement timing or the heat generation temperature gradually increases, so that the heat generation is excellent in real temperature feeling and the thermal effect. The body is provided.

  The present invention will be described below based on preferred embodiments with reference to the drawings.

  The exothermic molded body of the present embodiment is formed into a sheet shape, and an exothermic intermediate molded body including an oxidizable metal, a water retention agent, and a fibrous material contains an electrolyte component and water. Moreover, the state which does not contain an electrolyte component and water is called exothermic intermediate molded object.

In the exothermic molded body of the present embodiment, the temperature drop rate for 5 minutes from the time when the exothermic molded body reaches the maximum heat generation temperature to the end of heat generation is 0.7 to 10 ° C / 5 min, preferably 1.0 to 7.0. ° C / 5 min. When the temperature drop rate is within such a range, the oxidation efficiency of the oxidizable metal of the exothermic molded body is high and the heat generation performance is improved. At the end of use, the sign of the replacement time is felt due to the rapid decrease in temperature. The resulting exothermic molded body is thin and flexible, has sufficient exothermic characteristics, and has excellent functions such as emitting a sign indicating the end of use. Here, when the maximum heat generation temperature is reached, as shown in FIG. 1, t1 indicates the maximum temperature Tmax that can be taken in improving the heat generation temperature of the heating element, and when the heat generation ends, the heat generation temperature of the heating element. When t2 reaches the maximum value, the temperature decreases, and a sufficient time has elapsed, and at that environmental temperature, no increase or decrease in temperature is shown. Each time point is determined by the thermal evaluation method described below. Further, the temperature drop rate is a temperature that decreases within 5 minutes from the time when the heating element reaches the maximum temperature t1 to the time when the heat generation ends t2 (for example, temperature differences ΔT ₁ ,... ΔT _i. The absolute value of ΔT _n is the maximum value, and the temperature decrease for 5 minutes at each time point from when the heating element reaches the maximum temperature until the end of heat generation is obtained, and the maximum value is obtained.

  The exothermic molded body preferably has a temperature integrated value of 38 ° C. or higher per unit weight of the oxidizable metal (hereinafter also simply referred to as a temperature integrated value) of 500 (° C./min)/g or higher. (° C./min)/g or more is more preferable. When the temperature integrated value is within such a range, the amount of the oxidizable metal can be reduced, so that it is thinner and more flexible, and is excellent in wearability in actual use, and the amount of dust can be reduced. It is also environmentally friendly. The temperature integral value is obtained by the following formula 1 from the area of the 38 ° C. or higher portion of the temperature-elapsed time correlation diagram obtained by heat generation.

In addition, the duration time of 38 ° C. or more per unit weight of the oxidizable metal is the time ts when reaching 38 ° C. after the start of heat generation, and the temperature decreases to 38 ° C. after reaching the maximum heat generation temperature exceeding 38 ° C. The value obtained by dividing the difference from the time te by the weight M of the oxidizable metal contained in the exothermic molded body is obtained (see FIG. 1 and the following formula).
Duration of 38 ° C. or more per oxidizable metal unit weight = (te−ts) / M

  The exothermic molded body preferably has a thickness of 0.1 to 10 mm, and more preferably 0.2 to 5 mm. When the thickness is within such a range, the heat generation performance, mechanical strength, components such as the oxidizable metal and water retention agent are well fixed, and a stable and uniform thickness and composition distribution can be obtained. Further, it becomes difficult for the molded body to be broken due to the occurrence of pinholes, and the productivity and workability are improved. In addition, the bending strength of the molded body can be secured, it is difficult to easily cause brittle fracture, and the flexibility is also good, especially when it is attached to a body part such as the elbow, knee, face, etc. It can be used without feeling uncomfortable. In terms of productivity, the paper layer formation time and the drying time are hardly delayed, and the operability is improved. In addition, it has good heat generation performance and excellent workability such as bending.

The basis weight of the heat-generating molded article is preferably 50~10000g / m ^2, more preferably from 100~6000g / m ^2, further preferably 200~4000g / m ^2. When the basis weight is 50 g / m ² or more, a particularly stable sheet can be formed when an oxidizable metal having a large specific gravity is used. When the basis weight is 10,000 g / m ² or less, it is lightweight and has a good feeling of use, and productivity and operability are also good.

  The exothermic molded body preferably has an exothermic temperature of 30 to 100 ° C, and more preferably 35 to 90 ° C. Here, the heat generation reached temperature is obtained by cutting a test piece of 80 mm × 100 mm from the heat-generating molded body, and then packaging the air-permeable sheet and the non-moisture permeable sheet constituting the heat-generating formed body on both sides in a bag shape. In a 20 ° C., 50% RH environment in accordance with JIS S4100, a 7 mm thick polypropylene plate surface is maintained at 35 ° C., and two type I gauze stipulated by the Japanese Pharmacopoeia are stacked on top of each other. The bottom of the exothermic molded product when left standing on the evaluation table with the air-permeable sheet surface facing down, and heating 8 sheets of 100% cotton and 5.905 twin yarns from above. This is a value obtained by measuring the temperature with a thermocouple. The exothermic temperature of the exothermic molded body is measured according to the above-mentioned blending composition and the moisture permeability of the air-permeable sheet (JIS Z208), such as when a sudden heat generation is required depending on the product application, or a product that needs to be maintained at a relatively low temperature for a long time. The water vapor transmission rate, hereinafter referred to simply as the water vapor transmission rate in this specification, can be arbitrarily designed.

  As the oxidizable metal contained in the exothermic intermediate molded body, an oxidizable metal conventionally used in this type of exothermic molded body can be used without particular limitation. As the form of the oxidizable metal, it is preferable to use a form having a powdery or fibrous form from the viewpoint of handleability and moldability.

  Examples of the oxidizable metal having a powder form include iron powder, aluminum powder, zinc powder, manganese powder, magnesium powder, and calcium powder. Among these, handling property, safety, and manufacturing cost are included. Iron powder is preferably used. The oxidizable metal has a particle size (hereinafter referred to as the particle size, the maximum length in the form of powder, or dynamic light scattering because the fixability to a fibrous material and control of the reaction are good. Means an average particle diameter measured by a laser diffraction method, etc.) is preferably 0.1 to 300 μm, and contains 50% by weight or more of 0.1 to 150 μm in particle diameter. More preferably, it is used.

  Examples of the oxidizable metal having a fibrous form include steel fibers, aluminum fibers, and magnesium fibers. Among these, steel fibers, aluminum fibers, and the like are preferably used from the viewpoints of handleability, safety, and manufacturing cost. The oxidizable metal having a fibrous form should have a fiber length of 0.1 to 50 mm and a thickness of 1 to 1000 μm in terms of moldability, mechanical strength of the obtained molded body, surface smoothness, and heat generation performance. It is preferable to use it.

  The blending amount of the oxidizable metal in the exothermic intermediate molded body is preferably 10 to 95% by weight, and more preferably 30 to 80% by weight. When the blending amount is 10% by weight or more, the exothermic temperature of the exothermic molded body to be obtained can be increased to a level higher than a person feels by touching with a fingertip or the like, and the fibrous form described later constituting the exothermic molded body. Since the amount of the product and the adhesive component (flocculating agent, etc.) can be suppressed, the air permeability of the molded body becomes sufficient, and as a result, the reaction can sufficiently occur inside the molded body and the exothermic temperature can be sufficiently increased. . Further, the heat generation time can be made sufficiently long, the water supply by the water retention agent can be made sufficient, and the oxidizable metal does not easily fall off. In addition, since a fibrous material and an adhesive component, which will be described later, constituting the molded body can be maintained at a certain amount, mechanical strength such as bending strength and tensile strength can be sufficient. Here, the blending amount of the oxidizable metal in the exothermic intermediate molded body can be determined by an ash test according to JIS P8128 or a thermogravimetric instrument. In addition, for example, in the case of iron, it can be quantified by a vibration sample type magnetization measurement test or the like using the property that magnetization occurs when an external magnetic field is applied.

  As the water retention agent, a water retention agent that has been conventionally used for exothermic molded bodies can be used without any particular limitation. In addition to acting as a moisture retention agent, the water retention agent also has a function as an oxygen retention / supply agent for the oxidizable metal. Examples of the water retention agent include activated carbon (coconut husk charcoal, charcoal powder, calendar bituminous coal, peat, lignite), carbon black, acetylene black, graphite, zeolite, perlite, vermiculite, silica, cancrinite, fluorite and the like. Among these, activated carbon is preferably used because it has water retention ability, oxygen supply ability, and catalytic ability. As the water retention agent, it is preferable to use a powdery material having a particle size of 0.1 to 500 μm from the viewpoint that an effective contact state with an oxidizable metal can be formed. It is more preferable to use those containing at least wt%. As the water retention agent, a form other than the powder form as described above can be used. For example, a form of fiber form such as activated carbon fiber can also be used.

  The content of the water retaining agent in the exothermic intermediate molded body is 3 to 60% by weight, preferably 5 to 50% by weight, and more preferably 7 to 40% by weight. When the content is 3% by weight or more, moisture necessary for maintaining the reaction to such an extent that the oxidizable metal can be raised to the human body temperature or higher by the oxidation reaction can be accumulated in the exothermic molded body. In addition, since the air permeability of the exothermic molded body is sufficiently ensured, the oxygen supply is sufficiently obtained and the exothermic molded body has high heat generation efficiency. When the blending amount is 60% by weight or less, the heat capacity of the exothermic molded body with respect to the obtained calorific value can be kept small, so that the exothermic temperature rises greatly and a temperature rise that can be experienced by human beings is obtained. Further, since the occurrence of falling off of the water retention agent and the decrease in the fibrous material and the adhesive component described below constituting the heat-generating molded body can be suppressed, sufficient mechanical strength such as bending strength and tensile strength can be obtained.

  Examples of the fibrous material include, for example, vegetable fibers (cotton, kabok, wood pulp, non-wood pulp, peanut protein fiber, corn protein fiber, soy protein fiber, mannan fiber, rubber fiber, hemp, and Manila hemp. Sisal, New Zealand hemp, Rafu hemp, eggplant, rush, straw, etc.), animal fiber (wool, goat hair, mohair, cashmere, alkapa, Angola, camel, vicuña, silk, feather, down, feather, algin fiber, chitin Fiber, casein fiber, etc.) and mineral fiber (asbestos, etc.). Examples of synthetic fibers include semi-synthetic fibers (acetate, triacetate, oxide acetate, promix, chlorinated rubber, hydrochloric acid rubber, etc.), metal fibers , Carbon fiber, glass fiber and the like. Also, polyolefins such as high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, polyester, polyvinylidene chloride, starch, polyvinyl alcohol or polyvinyl acetate, or a single fiber such as a copolymer or modified product thereof, or these A core-sheath composite fiber having a resin component in the sheath can be used. Among these, polyolefins and modified polyesters are preferably used because they have high adhesive strength between fibers, are easy to form a three-dimensional network structure by fusion of fibers, and have a melting point lower than the ignition point of pulp fibers. Synthetic fibers such as polyolefin having branches are also preferably used because of their good fixability with oxidizable metals and water retention agents. These fibers can be used alone or in combination of two or more. In addition, these fibers can be used in the form of collected and reused. Of these, wood pulp and cotton are preferable from the viewpoints of the oxidizable metal, the fixability of the water retention agent, the flexibility of the resulting exothermic molded article, the oxygen permeability resulting from the presence of voids, the production cost, and the like. Used.

  The fibrous material preferably has a CSF (Canadian Standard Freeness) of 600 ml or less, and more preferably 450 ml or less. When the amount is 600 ml or less, the fixing property between the fibrous material and the components such as the oxidizable metal and the water retaining agent is sufficiently good, the predetermined blending amount can be maintained, and the heat generation performance can be sufficiently exhibited. In addition, a molded body having a uniform thickness is obtained, the fixing between the fibrous material and the component is good, the component is difficult to fall off, and the bond originates from the entanglement or hydrogen bonding between the component and the fibrous material. Strength can be given. Further, the mechanical strength such as bending strength and tensile strength can be sufficient, and the workability is also good.

The lower the CSF of the fibrous material, the better. However, in the case of normal pulp fiber-only papermaking, when the component ratio other than the fibrous material is low, the drainage is sufficiently good when the CSF is 100 ml or more, and dehydration. Can be sufficiently performed, and a heat-generating molded product having a uniform thickness can be obtained, and blister breakage does not occur during drying, and the moldability is improved. In the present invention, since the component ratio other than the fibrous material is high, it is possible to obtain an exothermic molded article having good drainage and uniform thickness. Further, since the CSF is lower as the CSF is lower, the fixability between the fibrous material and components other than the fibrous material is improved, and a high strength of the molded product can be obtained.
Adjustment of the CSF of the fibrous material can be performed by a beating process or the like. CSF may be adjusted by mixing low and high CSF fibers.

The fibrous material preferably has a negative (negative) surface charge. As the surface charge is strongly negatively charged, the fixability of powder components such as oxidizable metals and water retention agents to the fibrous material is good, and the powder holding property is improved. The heat generation characteristics are further improved. Further, it is possible to prevent a large amount of powder components such as an oxidizable metal and a water retaining agent from being mixed in the waste water in the wet papermaking process, and this does not adversely affect productivity and environmental conservation. In particular, from the viewpoint of further increasing the yield of the obtained paper-molded article, the fibrous material preferably has a charge amount of −2.5 × 10 ⁻⁶ eq / g or less, and the charge amount is −4. 0 × 10 ⁻⁶ eq / g or less is more preferable. Here, the charge amount of the fibrous material is measured by colloid titration. The same applies to the zeta potential, which is the apparent potential at the shear plane between the charged particle interface and the solution. The zeta potential is measured by streaming potential method, electrophoresis method or the like.

  The fibrous material preferably has an average fiber length of 0.1 to 50 mm, and more preferably 0.2 to 20 mm. By making the average fiber length within such a range, the mechanical strength such as bending strength and tensile strength of the exothermic molded body to be obtained can be sufficiently ensured, and the breathability of the exothermic molded body without excessively dense fiber layers. The oxygen supply is good, the oxygen supply is good, and the heat generation is excellent. Further, since the fibrous material can be uniformly dispersed in the exothermic molded body, uniform mechanical strength can be obtained, and a uniform thick exothermic molded body can be obtained. In addition, the fiber spacing does not become too wide, and the ability of the fiber to retain components such as the oxidizable metal and water retention agent is maintained, making it difficult for the component to fall off.

  The amount of the fibrous material in the exothermic intermediate molded body is preferably 2 to 50% by weight, and more preferably 5 to 40% by weight. When the blending amount is 2% by weight or more, it is possible to sufficiently prevent the components such as the oxidizable metal and the water retention agent from falling off and to make the exothermic molded body sufficient. When the blending amount is 50% by weight or less, the heat capacity with respect to the heat generation amount of the exothermic molded body can be suppressed, the temperature rise can be made sufficient, and the ratio of the components in the obtained exothermic molded body Can be ensured to a certain extent or more, so that the desired heat generation performance can be sufficiently obtained.

  The ratio of the content of the oxidizable metal and the water retention agent in the exothermic intermediate molded body is oxidizable metal: water retention agent = 45: 1 to 0.3-1 (weight ratio), preferably Oxidizable metal: water retention agent = 20: 1 to 1: 1, and the total content of the oxidizable metal and the water retention agent in the exothermic intermediate molded body is 50 to 98% by weight, preferably 60 to 95% by weight. %. When the content ratio of these components is in the above range, the oxidation efficiency of the oxidizable metal is high, and the heat generation performance of the heat generating molded body can be effectively improved.

It is preferable that a flocculant is added to the exothermic intermediate molded body as described later.
In addition, the exothermic intermediate molded body is usually used for paper making of a sizing agent, a coloring agent, a paper strength enhancer, a yield improver, a filler, a thickener, a pH control agent, a bulking agent, and the like as necessary. Additives can be added without particular limitation. The addition amount of the additive can be appropriately set according to the additive to be added.

The basis weight per sheet of the exothermic intermediate molded body is 10 to 1000 g / m ² , and more preferably 50 to 600 g / m ² . When the basis weight is 10 g / m ² or more, a particularly stable molded article can be formed when using a metal having a large specific gravity among oxidizable metals and the like. When the basis weight is 1000 g / m ² or less, it is lightweight and has a good feeling of use, and productivity and operability are also good.

The breaking length of the exothermic intermediate molded body is preferably 100 to 4000 m, and more preferably 200 to 3000 m. When the breaking length is within such a range, handling during use and production / operation can be facilitated. Here, the tearing length is determined by cutting a test piece of length 150 mm × width 15 mm from the heat-generating molded body, and then mounting the test piece on a tensile tester with a chuck interval of 100 mm according to JIS P8113. It is a value calculated by the following calculation formula after performing a tensile test at min.
Breaking length [m] = (1 / 9.8) × (Tensile strength [N / m]) × 10 ⁶ / (Test piece basis weight [g / m ² ])

  The thickness of the exothermic intermediate molded body is preferably 0.08 to 1.2 mm, and more preferably 0.1 to 0.6 mm. When the thickness is 0.08 mm or more, heat generation performance, mechanical strength, oxidizable metal, water retention agent, and other components are well fixed, and a stable and uniform thickness and composition distribution can be obtained. As a result, it becomes difficult for the molded body to be broken due to the occurrence of defects, and the productivity and workability are improved. When the thickness is 1.2 mm or less, the bending strength of the molded body can be secured, brittle fracture is not easily caused, and flexibility is also good, especially bending and stretching of body parts such as elbows, knees, and faces. When worn on the part to be worn, the wearability is poor and it can be used without feeling uncomfortable. In terms of productivity, paper layer formation time and drying time are hardly delayed, operability is good, heat generation performance is good, and workability such as bending is also excellent.

  As the electrolyte contained in the exothermic molded body, an electrolyte conventionally used in this type of exothermic molded body can be used without any particular limitation. Examples of the electrolyte include alkali metal, alkaline earth metal or heavy metal sulfates, carbonates, chlorides or hydroxides. Among these, various chlorides such as sodium chloride, potassium chloride, calcium chloride, magnesium chloride, and iron chloride (first and second) are preferably used from the viewpoint of excellent conductivity, chemical stability, and production cost. These electrolytes can be used alone or in combination of two or more.

  The amount of the electrolyte in the exothermic molded body is preferably 0.5 to 30% by weight, more preferably 1 to 25% by weight in terms of the weight ratio of water in the exothermic molded body. The blending amount of 0.5% by weight or more is preferable because the oxidation reaction of the exothermic molded body to be obtained can sufficiently proceed. When the blending amount is 30% by weight or less, precipitation of the electrolyte hardly occurs, the air permeability of the exothermic molded article is good, the electrolyte necessary for the exothermic function can be secured, and sufficient water is oxidizable. It is preferable because it is supplied to a metal or the like, has excellent heat generation performance, and can uniformly mix an electrolyte with a heat generation molded body.

  The exothermic molded body preferably has a moisture content (weight moisture content, hereinafter the same) of 5 to 80%, more preferably 10 to 60%. If the moisture content is 5% or more, sufficient water can be secured to maintain the oxidation reaction, and the oxidation reaction can be prevented from being terminated halfway. Therefore, uniform heat generation performance can be obtained. When the moisture content is 80% or less, the heat capacity of the obtained exothermic molded body can be kept low, the exothermic temperature can be sufficiently increased, and the breathability of the exothermic molded body can be sufficiently obtained. Therefore, the heat generation performance is excellent, and shape retention and mechanical strength are sufficiently obtained.

Next, a method for manufacturing the exothermic molded body will be described.
In producing the exothermic molded body, first, a raw material composition (slurry) containing the oxidizable metal, the water retention agent, the fibrous material, and water is prepared, and the exothermic intermediate molded body is formed from the raw material composition. It is preferable to form by papermaking.

The flocculant is preferably added to the raw material composition.
Examples of the flocculant include inorganic flocculants composed of metal salts such as sulfate band, polyaluminum chloride, ferric chloride, polyferric sulfate, and ferrous sulfate; polyacrylamide, sodium polyacrylate, polyacrylamide Mannich modified products, poly (meth) acrylic acid aminoalkyl ester-based, carboxymethylcellulose sodium-based, chitosan-based, starch-based, polyamide epichlorohydrin-based polymer flocculants; dimethyldiallylammonium chloride-based or ethyleneimine-based Organic coagulants such as condensates of alkylene dichloride and polyalkylene polyamines, dicyandiamide / formalin condensates; clay minerals such as montmorillonite and bentonite; silicon dioxide such as colloidal silica or hydrates thereof; hydrous magnesium silicate such as talc And the like. And among these flocculants, anionic colloidal silica, bentonite, etc. from the viewpoints of surface properties of the molded body, formation of texture, improvement of moldability, fixing rate of materials such as oxidizable metals and water retention agents, and improvement of paper strength The combined use of cationic starch, polyacrylamide and the like, and the combined use of anionic carboxymethyl cellulose sodium salt, polyacrylamide and cationic polyamide epichlorohydrin, and cationic and anionic agents such as polyacrylamide are particularly preferred. Besides these combinations, these flocculants may be used alone or in combination of two or more.

  The amount of the flocculant added is preferably 0.01 to 5% by weight, more preferably 0.05 to 1% by weight, based on the solid content of the raw material composition. When the content is 0.01% by weight or more, the coagulation effect is excellent, the falling off of components such as oxidizable metals and water retention agents during papermaking can be suppressed, the raw material composition becomes uniform, and the heat generation is uniform in thickness and composition. It is excellent in that a molded body can be obtained. When the added amount is 5% by weight or less, it is possible to suppress the occurrence of tearing, burning, scorching, etc., sticking to a drying roll during drying, excellent productivity, and maintaining a good potential balance of the raw material composition. This is excellent in that the amount of the component dropped into the white water during papermaking can be suppressed. Moreover, the oxidation reaction of the exothermic molded body proceeds, and the storage stability such as exothermic characteristics and strength is excellent.

  The concentration of the raw material composition is preferably 0.05 to 10% by weight, and more preferably 0.1 to 2% by weight. A concentration of 0.05% by weight or more is preferable in that a large amount of water is not required and a long time is not required for forming the exothermic molded body, and an exothermic molded body having a uniform thickness can be formed. When the concentration is 10% by weight or less, the dispersion state of the raw material composition is good, the surface properties of the resulting molded article are excellent, and the molded article having a uniform thickness is excellent.

Next, the raw material composition is paper-made to form the exothermic intermediate molded body.
Examples of the paper making method of the exothermic intermediate formed body include a paper making method using a circular paper machine, a continuous paper machine, a Yankee paper machine, a twin wire paper machine, etc., which are continuous paper machines, and a batch type paper making method. The manual method etc. are mentioned. Furthermore, an exothermic intermediate molded body can be formed by multi-layer sheeting using the raw material composition and a composition having a composition different from the raw material composition. Further, the exothermic intermediate molded body obtained by papermaking the raw material composition is bonded to a plurality of layers, or a molded body obtained from a composition having a composition different from that of the raw material composition is formed on the exothermic intermediate molded body. The exothermic intermediate molded body can be molded by bonding.

  The exothermic intermediate molded body is dehydrated until the moisture content (weight moisture content, the same shall apply hereinafter) is 70% or less from the viewpoint of maintaining the form after paper making (shape retention) and maintaining the mechanical strength. It is preferable to dehydrate until it becomes 60% or less. Examples of the dehydration method of the exothermic intermediate molded body after papermaking include dehydration by suction, a method of dehydrating by blowing pressurized air, a method of dehydrating by pressing with a pressure roll or a pressure plate, and the like.

  An exothermic intermediate molded body containing the oxidizable metal (having heat reactivity in a normal atmosphere) is actively dried to separate moisture, thereby suppressing oxidation of the oxidizable metal during the manufacturing process. An exothermic intermediate molded body excellent in long-term storage stability can be obtained. Furthermore, in addition to the point of increasing the supporting force of the oxidizable metal to the fibrous material after drying and suppressing its falling off, from the point of expectation of improvement in mechanical strength due to the addition of a hot melt component and a thermal crosslinking component, It is preferable to dry the exothermic intermediate molded body after papermaking of the exothermic intermediate molded body and before containing the electrolytic solution of the electrolyte.

  The exothermic intermediate molded body is preferably dried by heat drying. In this case, the heat drying temperature is preferably 60 to 300 ° C, more preferably 80 to 250 ° C. By setting the heating and drying temperature of the exothermic intermediate compact to such a temperature range, the drying time can be shortened, so that the oxidation reaction of the oxidizable metal accompanying moisture drying can be suppressed, and the heat generation of the resulting exothermic compact is obtained. It can prevent a decline in sex. Moreover, since only the front and back layers of the exothermic molded body can suppress the oxidation reaction of the oxidizable metal, discoloration to light brown can be prevented. In addition, since the performance deterioration of the water retaining agent can be suppressed, the heat generation effect of the exothermic molded body can be maintained, and the structure of the exothermic molded body can be destroyed due to the rapid evaporation of moisture inside the exothermic intermediate molded body. Can be prevented.

  The moisture content of the exothermic intermediate molded body after drying is preferably 20% or less, and more preferably 10% or less. When the moisture content is 20% or less, excellent long-term storage stability is obtained. For example, even when temporarily stored in a wound roll state, moisture does not easily move in the thickness direction of the roll, and heat generation performance and mechanical strength are improved. No change and excellent.

  The drying method of the exothermic intermediate molded body may be appropriately selected according to the thickness of the exothermic intermediate molded body, the processing method of the exothermic intermediate molded body before drying, the moisture content before drying, the moisture content after drying, and the like. it can. Examples of the drying method include drying methods such as contact with a heating structure (heating element), spraying of heated air or steam (superheated steam), vacuum drying, electromagnetic wave heating, and electric heating. Moreover, it can also implement simultaneously with the above-mentioned dehydration method.

  The exothermic intermediate molded body is preferably molded (dehydrated and dried) in an inert gas atmosphere. However, as described above, the exothermic intermediate molded body does not contain an electrolyte that serves as an oxidizing aid. Accordingly, molding can be performed in a normal air atmosphere. For this reason, manufacturing equipment can be simplified. Since the obtained exothermic intermediate molded body is thin and difficult to break, it can be wound up in a roll shape as necessary.

  The dried exothermic intermediate molded body can be pierced by performing creping, slitting, trimming, or needle punching as necessary. Moreover, by making the raw material composition contain a thermoplastic resin component or a hot water decomposing component, it is possible to perform heat sealing and facilitate bonding.

  Next, the electrolyte is contained in the exothermic intermediate molded body. The step of containing the electrolyte is preferably performed in an inert gas atmosphere such as nitrogen or argon. However, when the electrolyte is added by impregnation with the electrolytic solution, the oxidation reaction immediately after the addition is gentle, The electrolyte may be contained in an air atmosphere.

  The method of incorporating the electrolyte into the exothermic intermediate molded body can be appropriately set according to the processing method of the exothermic intermediate molded body after papermaking, the water content, the form, the layer configuration when it is made into multiple layers, and the like. Examples of the method of containing the electrolyte include a method of impregnating the exothermic intermediate molded body with an electrolyte solution having a predetermined concentration of the electrolyte, and adding the electrolyte having a predetermined particle size in a solid state to generate an exothermic intermediate molded body. And the like. From the viewpoint that the electrolyte can be uniformly contained in the exothermic intermediate molded body and that the water content can be adjusted at the same time, a method of impregnating an electrolytic solution of a predetermined concentration is preferable.

  As described above, when the exothermic intermediate molded body is impregnated with the electrolyte, the impregnation method can be appropriately selected according to the form such as the thickness of the exothermic intermediate molded body and the water content. The impregnation method includes a method of spray-coating the electrolytic solution having a predetermined concentration onto the exothermic intermediate molded body, and injecting the electrolytic solution into a part of the exothermic intermediate molded body with a syringe or the like, thereby causing capillary action of the fibrous material. A method of infiltrating the whole exothermic intermediate molded body using a method, a method of coating with a brush, a method of immersing in the electrolytic solution, a gravure coating method, a reverse coating method, a doctor blade method, etc., among these The spray coating method is preferred because it can distribute the electrolyte uniformly, is simple, and requires relatively little equipment cost. In addition, in the case of products with complicated shapes and layer configurations, the concentration of the specified concentration is improved from the viewpoint that productivity is improved, the final finishing can be performed as a separate process, the production flexibility is improved, and the equipment is simplified. A method of injecting the electrolytic solution with a syringe or the like is preferable. This method of injecting the electrolytic solution can also be performed after the multilayered sheet is accommodated in a predetermined container.

  After the electrolyte is contained in the exothermic intermediate molded body as described above, the moisture content is adjusted as necessary to stabilize the exothermic molded body. Then, if necessary, it can be trimmed and processed into a predetermined size. The obtained exothermic molded body is provided by being wrapped with an oxygen-impermeable packaging material when not in use.

  As described above, the exothermic molded body of the present embodiment functions as a sign of replacement time because the temperature rapidly decreases from the time when the maximum heat generation temperature is reached until the end of heat generation, and the heat generation temperature gradually increases. By this, it is excellent in a real temperature feeling and a thermal effect.

  Further, since it is formed into a sheet shape, it can be applied to various uses, and is particularly excellent in wearability when worn on the body or the like. Further, since the heat generation efficiency is high, the amount of oxidizable metal used can be reduced, and a heat generation molded body that is thinner and rich in flexibility can be obtained. Furthermore, it leads to the reduction of dust and becomes an environmentally friendly exothermic molded body.

  The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention.

  The exothermic molded body of the present invention is preferably formed into a sheet shape as in the above embodiment, but it is formed into a three-dimensional shape by providing a three-dimensional surface of a papermaking mold used for papermaking. You can also.

Hereinafter, the exothermic molded body of the present invention will be described more specifically with reference to examples.
An exothermic intermediate molded body having a solid content-containing composition shown in Table 1 was produced. Furthermore, the exothermic molded object shown in Table 2 was produced from the obtained exothermic intermediate molded object as follows. And the content ratio of iron and activated carbon of the obtained exothermic intermediate molded body, the content ratio of iron and activated carbon, and the weight and exothermic characteristics of the exothermic molded body (maximum exothermic temperature, duration of 38 ° C or more, exothermic descending rate and temperature integration) Value) was examined as follows. The results are shown in Tables 1 and 2 and FIG.

[Example 1]
<Combination of raw material composition>
Fibrous material: Pulp fiber (NBKP, manufacturer: Fletcher Challenge Canada, trade name “Mackenzie”, CSF 200 ml) 15% by weight
Oxidizable metal: Iron powder (trade name “RKH”, manufactured by Dowa Iron Mining Co., Ltd.) 75% by weight
Water retention agent: Activated charcoal (Nippon Enviro Chemical Co., Ltd., trade name “Carborafine”) 10% by weight
Cationic flocculant: polyamide epichlorohydrin resin (manufactured by Seiko PMC Co., Ltd., trade name “WS4020” with respect to 100 parts by weight of the solid content of the above raw material composition (total of fibrous material, oxidizable metal and water retention agent) ] 0.35 parts by weight and anionic flocculant: sodium carboxymethylcellulose (Daiichi Kogyo Seiyaku Co., Ltd., trade name “WS-C” 0.18 parts by weight Water: industrial water, solid content concentration 3% by weight Add until

<Making conditions>
Using the above raw material composition, it was diluted with water to 0.3% by weight immediately before the paper making head, and paper was made with a slanted short net paper machine to produce a wet shaped sheet.

<Drying conditions>
It was sandwiched with felt and dehydrated under pressure, passed through a heating roll at 120 ° C. as it was, and dried until the water content became 5% by weight or less. And the papermaking sheet | seat (heat_generation | fever intermediate molded object) of basic weight 180g / m < ² > and thickness 0.25mm was obtained. As a result of measuring the composition of the obtained exothermic intermediate molded body using a thermogravimetric measuring device (TG / DTA6200, manufactured by Seiko Instruments Inc.), it was 70% by weight of iron, 12% by weight of activated carbon, and 18% by weight of pulp (iron) : Activated carbon (weight ratio) = 70: 12, iron and activated carbon total content 82%).

<Preparation of exothermic molded body>
The obtained exothermic intermediate molded body was cut into 80 mm × 100 mm, six sheets were stacked, and the following electrolytic solution was injected so that the amount of the electrolytic solution was 60 parts by weight with respect to 100 parts by weight of the exothermic intermediate molded body. Using the phenomenon, the entire molded body was infiltrated to obtain a sheet-like exothermic molded body. Then, the exothermic molded body was inserted into a bag-like shape having a non-breathable sheet made of polyethylene on one side and a breathable sheet (polyethylene, microporous sheet, moisture permeability of 1000 g / m ² ) on the other side, Was heat-sealed to produce a heating element.
<Electrolyte>
Electrolyte: Purified salt (NaCl)
Water: Industrial water Electrolyte concentration: 5% by weight

[Comparative Example 1]
As Comparative Example 1, a commercial product (manufactured by Hisamitsu Pharmaceutical Co., Ltd., trade name “Salonship Direct Paste”) was used.

[Composition of exothermic molded body]
The composition of the exothermic molded body obtained was calculated from the composition of the exothermic intermediate obtained in Example 1 and the concentration and addition amount of the added electrolyte. The composition of Comparative Example 1 was calculated from ICP emission spectroscopic analysis and thermogravimetry.

[Evaluation of heat generation characteristics]
The heating temperature of the heating element was measured by the above-described temperature measuring method. And from the time-dependent change of the obtained exothermic temperature, the exothermic maximum temperature, the temperature drop rate, and the temperature integrated value were obtained by the above-described method.

  As shown in Tables 1 and 2 and FIG. 2, the exothermic molded body (heating element) of the example took a temperature curve in which the exothermic temperature gradually increased and the temperature rapidly decreased at the end of the exotherm. Further, the temperature integration value was 500 ° C. · h / g or more and the consumption rate of iron was very high, the duration was extremely long as 1.7 h / g, and the heat generation efficiency was very high. On the other hand, the exothermic molded body (heating element) of the comparative example drawn a curve of a gradual temperature decrease, and the temperature integrated value and the duration were lower than those of the examples. Moreover, although the heat generating body of the Example was lightweight and thin, it had almost the same thermal performance as the comparative example.

  Although there is no particular limitation on the use of the heat-generating molded body of the present invention, the sign of the replacement time when used for the human body, etc., utilizing the characteristics that the temperature rapidly decreases from the maximum heat generation temperature and the characteristics that the temperature gradually increases In industrial applications, it is suitable for applications such as those that promote thermosetting such as adhesives, and improvements in the sustained release function of agents from heat-shrinkable gels.

It is a figure which shows typically the time-dependent change of the exothermic temperature of the exothermic molded object of this invention. It is a figure which shows the time-dependent change of the exothermic temperature of the exothermic molded object by the Example and comparative example of this invention.

Claims (4)

An exothermic molded body containing an electrolyte and water in an exothermic intermediate molded body containing an oxidizable metal, a water retention agent and a fibrous material,
The ratio of the oxidizable metal and the content of the water retention agent in the exothermic intermediate molded body is 45: 1 to 0.3: 1 (weight ratio), and the coated object in the exothermic intermediate molded body is The total content of the oxidizing metal and the water retention agent is 50 to 98% by weight,
The exothermic molded body having a temperature drop rate of 0.7 to 10 ° C / 5 min from the time when the exothermic molded body reaches the maximum heat generation temperature to the end of heat generation.   2. The exothermic molded body according to claim 1, wherein a temperature integrated value of 38 ° C. or more per unit weight of the oxidizable metal is 500 (° C. · min) / g or more.   The exothermic molded body according to claim 1 or 2, wherein the exothermic intermediate molded body is produced by a wet papermaking method. The exothermic molded body according to any one of claims 1 to 3, wherein the exothermic molded body is formed into a sheet shape and has a thickness of 0.1 to 10 mm.

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