WO2023190281A1

WO2023190281A1 - Planar heating device

Info

Publication number: WO2023190281A1
Application number: PCT/JP2023/012082
Authority: WO
Inventors: 詠未山森
Original assignee: 坂口電熱株式会社
Priority date: 2022-04-01
Filing date: 2023-03-27
Publication date: 2023-10-05

Abstract

The present invention addresses the problem of providing a planar heating device in which the area of contact between a fluid and a heat-generating portion is large. As a solution, a planar heating device is provided which comprises a first thermoplastic resin substrate, a second thermoplastic resin substrate, and a heat-transfer material that is formed between the first and second thermoplastic resin substrates by fusing. A planar heat-generating body having a resistive heat-generating coating layer is embedded in the first thermoplastic resin substrate.

Description

Planar heating device

The present invention relates to a planar heating device.

Tape-shaped heaters are used to heat pipes, etc. Tape-shaped heaters are used by being wrapped around the outer periphery of piping, etc., and if there is a gap between the object to be heated and the heater, the heat conductivity will be reduced. In Patent Document 1, the applicant has proposed a tape-shaped heater having a heating element made of a heat-resistant electrically insulating thread coated with conductive powder. The tape-shaped heater described in Patent Document 1 has a heat-generating element in the form of a thread, so it has excellent flexibility and can be easily wrapped closely around a rigid pipe or the like. However, with tape-shaped heaters, if the object to be heated itself is flexible, it is difficult to install it because wrapping it too tightly will deform the object. It may deform and create gaps.

Cultivation of microorganisms, human-derived cells, etc. needs to be carried out in a specific temperature range (for example, for human-derived cells, it is around 37°C, and if the temperature exceeds 42°C, the cells will be destroyed). Culture requires supply of sugars, amino acids, nutrients, oxygen, etc. for cell survival, and medium exchange is performed to supply new medium and drain old culture solution. At this time, the supplied medium is heated in advance to the same temperature as the culture temperature so that the temperature does not change depending on the supplied medium. Patent Document 2 discloses an invention of a culture medium warming device that has a housing having a heating space and heats the culture medium by arranging a liquid feeding tube inside the housing. The device described in Patent Document 2 has poor thermal efficiency because it heats the culture medium in the liquid feeding tube with warm air, and the housing is large because it is necessary to arrange the liquid feeding tube of sufficient length inside the housing. It turns into In addition, in a culture device, many parts are single-use (used only once) and are disposable in order to prevent contamination (contamination due to contamination and multiplication of bacteria during culture), but as described in Patent Document 2 This device requires a large amount of disposable tubes and is expensive.

Japanese Patent Application Publication No. 2010-003464 Japanese Patent Application Publication No. 2014-113109

An object of the present invention is to provide a planar heating device that has excellent adhesion to an object to be heated.

The present invention is intended to solve the above problems, and specific means are as follows.
1. a first thermoplastic resin base in which a planar heating element is embedded;
a second thermoplastic resin base;
a deformable heat transfer material sealed between the first and second thermoplastic resin bases so as to cover the entire heating area of the planar heating element;
has
The planar heating element includes a base material and a resistance heating coating layer coated on the base material,
The thickness of the second thermoplastic resin base is 50 μm or more and 400 μm or less,
A planar heating device characterized in that the thickness of the base material is twice or more the thickness of the second thermoplastic resin base material.
2. 1. The heat transfer material has a Shore E hardness of 1 or more and 50 or less. The planar heating device described in .
3. 1. The base material is paper. or 2. The planar heating device described in .
4. 1. The heat transfer material is one or more selected from rubber, clay, gel, and solid oil. ~3. The planar heating device according to any one of the above.
5. Two or more of the planar heating elements are embedded in the first thermoplastic resin base,
1. The first thermoplastic resin base is bendable with the first thermoplastic resin base on the outside. ~4. The planar heating device according to any one of the above.

The planar heating device of the present invention has a heat transfer material above the heating region, and this heat transfer material can be deformed to follow the shape of the object to be heated, so that excessive pressure is applied to the object to be heated. You can get close to it without any problems. In the sheet heating device of the present invention, the second thermoplastic resin base located on the side of the object to be heated is more flexible than the first thermoplastic resin base, so that when pressure is applied from the heat transfer material, the second thermoplastic resin base is more flexible than the first thermoplastic resin base. The second thermoplastic resin base can be greatly deformed and come into close contact with the object to be heated. In the planar heating device of the present invention, since the heat transfer material covers the entire surface of the heating region, dry heating can be prevented. Since the planar heating device of the present invention can efficiently heat an object to be heated, for example, when heating a tube for supplying a culture medium, the tube in contact with the planar heating device of the present invention can be shortened. can do.

1 is a schematic diagram of a planar heating device according to a first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of a planar heating device according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a first thermoplastic resin base included in the planar heating device according to the first embodiment of the present invention. FIG. 2 is an exploded view of a first thermoplastic resin base included in the planar heating device according to the first embodiment of the present invention. FIG. 2 is a perspective view from both sides of a sheet heating element included in the sheet heating device according to the first embodiment of the present invention. FIG. 3 is a diagram showing how the sheet heating device of the present invention is used. FIG. 2 is a schematic diagram of a planar heating device according to a second embodiment of the present invention. FIG. 2 is an exploded view of a planar heating device according to a second embodiment of the present invention. FIG. 3 is a schematic diagram of a planar heating device according to a third embodiment of the present invention. FIG. 3 is a schematic diagram of a planar heating device according to a fourth embodiment of the present invention.

"First embodiment"
1 and 2 show a schematic diagram and an exploded view of a planar heating device 100, which is a first embodiment of the present invention.
The planar heating device 100 includes a first thermoplastic resin base 11 in which two planar heating elements 14a and 14b are embedded, a second thermoplastic resin base 12, and a heat transfer material sealed between them. 13a, b. The first thermoplastic resin base 11 and the second thermoplastic resin base 12 are integrated by being fused to form a space between which the heat transfer materials 13a and 13b are sealed. A heating device 100 is formed.

"Thermoplastic resin base"
The second thermoplastic resin base 12 has a thickness of 50 μm or more and 400 μm or less. By having a thickness within this range, the second thermoplastic resin base 12 has an excellent balance between deformability (flexibility) and strength, and is easily deformed following the deformation of the heat transfer materials 13a and 13b. , and can prevent stretching and tearing. The thickness of the second thermoplastic resin base 12 is preferably 80 μm or more, more preferably 100 μm or more, even more preferably 120 μm or more, even more preferably 150 μm or more, and , is preferably 350 μm or less, more preferably 300 μm or less.
In addition, in this specification, the thickness of the second thermoplastic resin base 12 means the thickness of the second thermoplastic resin base 12 in the region where the heat transfer materials 13a and 13b are sealed.

The second thermoplastic resin base 12 has recesses 121a and 121b filled with heat transfer materials 13a and 13b. The depths of the recesses 121a and 121b are not particularly limited and can be adjusted depending on the size, shape, etc. of the object to be heated. The recesses 121a and 121b can be formed by a known method such as vacuum forming, pressure forming, hot stamping, or the like. When forming the recesses 121a and 121b, it is preferable to form fine irregularities on their inner surfaces because the contact area with the heat transfer materials 13a and 13b becomes larger and heat conduction is improved. As for the fine irregularities, the developed area ratio (Sdr) of the interface is preferably 0.05 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. Note that the developed area ratio of the interface can be calculated from a surface profile of 1000 μm×1000 μm or more using a laser microscope or the like.

3 and 4 show a schematic diagram and an exploded view of the first thermoplastic resin base 11 included in the planar heating device 100.
The first thermoplastic resin base 11 includes a first thermoplastic resin sheet 111 and a second thermoplastic resin sheet 112, and from the one farthest from the second thermoplastic resin base 12, the first thermoplastic resin Sheet 111/planar heating elements 14a, b/second thermoplastic resin sheet 112 are laminated in this order. The first and second thermoplastic resin sheets 111 and 112 are integrated by being thermally fused with the planar heating elements 14a and 14b sandwiched therebetween, thereby forming the first thermoplastic resin base 11. are doing.

The first and second thermoplastic resin substrates 11 and 12, as well as the first thermoplastic resin sheet 111 and the second thermoplastic resin sheet 112, are both made of thermoplastic resin. The thermoplastic resin is not particularly limited, and polyethylene, polypropylene, polystyrene, polyester, polycarbonate, polyamide, polyimide, acrylic resin, fluororesin, etc. can be used, and different types of thermoplastic resins that can be heat-sealed to each other can be used. A combination of resins can also be used. Among these, it is preferable to use polyethylene, which is inexpensive and can be sterilized by γ-ray irradiation, or polypropylene or fluororesin, which can be sterilized by autoclaving. As the polyethylene, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc. can be used without particular limitation. As the fluororesin, PTFE, PFA, FEP, etc. can be used without particular limitation.

In the first thermoplastic resin base 11, the first thermoplastic resin sheet 111 and the second thermoplastic resin sheet 112 may have the same thickness or different thicknesses. Moreover, the first thermoplastic resin sheet 111 and the second thermoplastic resin sheet 112 can also have different thicknesses for each part. The first and second thermoplastic resin sheets 111, 112, especially the second thermoplastic resin sheet 112 located on the heat transfer material 13 side, are preferably thinner in terms of heat transfer properties, but if they are too thin, the strength will decrease. It becomes weaker and more likely to break. Therefore, the thickness of the first and second thermoplastic resin sheets 111 and 112 is preferably 100 μm or more and 400 μm or less, more preferably 120 μm or more, even more preferably 150 μm or more, and 350 μm or less. It is more preferable that it is, and it is still more preferable that it is 300 μm or less.
If the thickness of the first and second thermoplastic resin sheets 111 and 112 is too thin compared to the buried planar heating elements 14a and 14b, when the first thermoplastic resin base 11 is deformed, etc. Peeling of the fusion bond or tearing of the sheet may occur at the ends of the planar heating elements 14a and 14b sandwiched therein. Therefore, the thickness of the first and second thermoplastic resin sheets 111, 112 is preferably 10% or more, and 15% or more of the thickness of the base materials 141a, b included in the planar heating elements 14a, b. More preferably, it is 20% or more.
Further, it is preferable that the area of the second thermoplastic resin sheet 112 that contacts the heat transfer material 13 has fine irregularities because the contact area with the heat transfer materials 13a and 13b increases and thermal conductivity improves. . The fine irregularities can be formed by known embossing or the like. As for the fine irregularities, the developed area ratio (Sdr) of the interface is preferably 0.05 or more, more preferably 0.1 or more, and even more preferably 0.2 or more.

"Heat transfer material"
The heat transfer materials 13a, b are housed in the recesses 121a, b of the second thermoplastic resin base 12 between the first thermoplastic resin base 11 and the second thermoplastic resin base 12, It is sealed. In the planar heating elements 14a and 14b, the area sandwiched between the conductive parts 143A and 143B of the resistance heating coating layers 142a and 142b is a heating area that generates heat when energized. The heat transfer materials 13a and 13b are provided so as to cover the entire surface of this heating area. Thereby, since the heat transfer materials 13a and 13b are always present on the heating region, dry heating can be prevented.

The heat transfer materials 13a and 13b are not particularly limited as long as they are deformable materials. Further, the deformation may be either elastic deformation or plastic deformation.
It is preferable that the heat transfer materials 13a and 13b have a Shore E hardness of 1 or more and 50 or less when a 10 mm thick sample is measured at 25° C. in accordance with JIS K6253-3, since these materials have excellent deformability. The Shore E hardness is more preferably 3 or more, further preferably 5 or more, and preferably 40 or less, more preferably 30 or less.

In terms of thermal conductivity, the heat transfer materials 13a and 13b preferably have high thermal conductivity, preferably 1 W/m·K or more, and preferably 1.5 W/m·K or more. is more preferable, and even more preferably 2 W/m·K or more. Here, the thermal conductivity of the thermoplastic resin is about 0.2 to 0.4 W/m·K. The heat transfer materials 13a, b transmit heat to the heated object via the second thermoplastic resin base 12, but the thermal conductivity values of the heat transfer materials 13a, b and the thermoplastic resin base 12 are different. If the difference becomes large, heat will be trapped inside, so the thermal conductivity of the heat transfer materials 13a and 13b is preferably 40 W/m·K or less, more preferably 30 W/m·K or less, More preferably, it is 10 W/m·K or less.
The heat transfer materials 13a and 13b should have low specific heat in order to reduce the energy required to heat the heat transfer materials and to precisely control the temperature by shortening the time required for heat to be transferred to the heated object. The specific heat is preferably 3 J/g·K or less, more preferably 2 J/g·K or less, and even more preferably 1 J/g·K or less.

For example, rubber, clay, gel, solid oil, liquid oil, metal fine particles, etc. can be used for the heat transfer materials 13a, b. Solid oil is an oil that is solid at 25°C, such as hydrogenated castor oil (melting point 80-90°C), carnauba wax (melting point 80-86°C), microcrystalline wax (melting point 80-85°C). , 12-hydroxystearic acid (melting point 76°C), candelilla wax (melting point 68-72°C), beeswax (melting point 63°C), petrolatum (melting point 53°C), white wax (melting point 45-55°C), lanolin (melting point 41°C), palm oil (melting point 37°C), and the like.
If the heat transfer materials 13a and 13b are fluid materials such as liquids or powders, there is a risk that they will flow during use and reduce their adhesion to the heated object, and if the thermoplastic resin base is torn. If this happens, the heat transfer materials 13a and 13b will flow out. Furthermore, when the heat transfer materials 13a and 13b are liquids, there is a risk that air bubbles will be generated inside when heated to a high temperature, and the air bubbles will cause dry heating. Therefore, the heat transfer materials 13a and 13b are preferably solids that do not flow at the operating temperature, and specifically, preferably one or more selected from rubber, clay, gel, and solid oil. Furthermore, the hardness changes little due to temperature changes, the thermal conductivity and specific heat values can be adjusted by incorporating fine metal particles, etc., and bubbles are less likely to occur even when heated, so rubber It is more preferable that the material is one or more selected from , and clay.

"Surface heating element"
A planar heating device 100, which is one embodiment, includes two planar heating elements 14a and 14b. FIG. 5 shows perspective views of the sheet heating elements 14a and 14b as seen from the front and back, respectively.
The planar heating elements 14a, b include base materials 141a, b and resistance heating coating layers 142a, b formed by coating on the base materials 141a, b, and the thickness of the base materials 141a, b is as follows. It is at least twice the thickness of the second thermoplastic resin base 12. The resistance heating coating layers 142a and 142b are provided on the heat transfer material 13 side.
Conductive parts 143A, B are provided on two opposing sides of the resistance heating coating layers 142a, b, and lead wires 144A, B are connected to the conductive parts 143A, B, respectively.

- Base material The base materials 141a, b are not particularly limited as long as the coated surface is insulating and the material is capable of forming a uniform coating layer of the resistance heating coating layers 142a, b on the coated surface. For example, paper, resin films, ceramics, laminates thereof, etc. can be used. Among these, paper is preferable because it is inexpensive and allows the formation of resistance heating coating layers 142a, b that are difficult to peel off from the base materials 141a, b by allowing a portion of the coating liquid to penetrate therein. Furthermore, non-coated paper is more preferable because it has excellent adhesion to the resistance heating coating layers 142a, b and the thermoplastic resin sheets 111, 112.

The thickness of the base materials 141a and 141b is at least twice the thickness of the second thermoplastic resin base 12. The first thermoplastic resin base 11 has base materials 141a and 141b embedded therein that have a thickness twice or more that of the second thermoplastic resin base 12 (100 μm or more and 400 μm or less). It is more rigid than the thermoplastic resin base 12 of . As a result, when the heat transfer materials 13a and 13b are deformed while being pressed against an object to be heated, the more flexible second thermoplastic resin base 12 side deforms more than the more rigid first thermoplastic resin base 11 side. Therefore, the second thermoplastic resin base 12 can be brought into close contact with the object to be heated and heated efficiently. The thickness of the base materials 141a, b is preferably 2.5 times or more, more preferably 3 times or more, and preferably 4 times or more the thickness of the second thermoplastic resin base 12. More preferred. On the other hand, if the base materials 141a, b become too thick, when the first thermoplastic resin base 11 is deformed, the first and second thermoplastic resin sheets 111, 112 will be damaged at the ends of the base materials 141a, b. becomes easy to peel off. Therefore, the thickness of the base material 141 is preferably 2 mm or less, more preferably 1.5 mm or less, and even more preferably 1.2 mm or less. Further, the basis weight of the base material 141 is preferably 400 g/m ² or more and 800 g/m ² or less. When having a plurality of planar heating elements, the material, thickness, basis weight, etc. of each base material of each planar heating element may be the same or different; From this point of view, it is preferable that they be the same.

- Resistance heating coating layer The resistance heating coating layers 142a and 142b are formed by applying a heating paint containing at least a conductive material and a binder resin onto the base materials 141a and 141b and drying it. The heat-generating paint may be either water-based or organic solvent-based, but water-based paints are preferred because they are less of a burden on workers and the environment, and are superior in safety without the risk of fire or explosion.

As the conductive material, those conventionally used in the resistance heating coating layer can be used without particular restriction, such as carbon-based conductive materials such as carbon black, graphite, carbon nanotubes, fullerene, carbon fiber, etc. One or more of metal conductive materials such as gold, silver, copper, and nickel, and ceramic conductive materials such as tungsten carbide, titanium nitride, zirconium nitride, and titanium carbide can be used. Among these, carbon-based conductive materials are preferred because those with small particle sizes can be obtained at low cost.
The conductive material is preferably contained in a proportion of 30 parts by weight or more and 70 parts by weight or less based on 100 parts by weight of the solid content of the resistance heating coating layer.

As the binder resin, any material that can be dissolved or dispersed in the heat-generating paint can be used without any particular restriction.For example, polyimide resin, silicone resin, polyamide resin, polyurethane resin, polyester resin, acrylic resin. , vinyl resin, epoxy resin, etc., or two or more of them can be used. Among these, one or more of polyimide resins, silicone resins, and polyamide resins are preferred because they have excellent heat resistance.
The binder resin is preferably contained in a proportion of 15 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the solid content of the resistance heating coating layer.

When the heat-generating paint is a water-based paint, it preferably contains water-swellable synthetic mica. Water-swellable synthetic mica absorbs water between its layers and swells. Water-based paints containing swollen mica exhibit thixotropy, in which the viscosity decreases when shear stress is applied, and the viscosity increases when no stress is applied. Therefore, a water-based heat-generating paint containing water-swellable synthetic mica is easy to apply and does not drip easily after coating, making it easy to form a uniform resistance heat-generating coating layer.
When water-swellable synthetic mica is contained, the water-swellable synthetic mica is preferably contained in a proportion of 3 parts by weight or more and 40 parts by weight or less based on 100 parts by weight of the solid content of the resistance heating coating layer.

The water-swellable synthetic mica preferably has an average particle diameter (median diameter) of 2 μm or more and 20 μm or less, which is derived from the volume distribution measured by a laser diffraction scattering method. When the average particle diameter is within the above range, dispersibility and coating properties in water-based heat-generating paints are excellent, and a uniform coating film (resistance heat-generating coating layer) is easily formed. This average particle diameter is more preferably 2 μm or more and 10 μm or less.

The heat-generating paint may contain additives such as a dispersant, a leveling agent, an antifoaming agent, and a curing agent within a range that does not impede the effects of the present invention.
The solid concentration of the heat-generating paint is adjusted so that it has a viscosity suitable for the application method. The solid content concentration can be, for example, about 5% by weight or more and 50% by weight or less depending on the viscosity determined by the coating method and the like.

The resistance heating coating layers 142a and 142b are formed by applying a heating paint onto the base materials 141a and 141b and drying it. The resistance heat generating coating layers 142a and 142b may be formed from a single heat generating paint, or may be formed by separately applying a plurality of types of heat generating paints having different compositions. It may also be a single layer or a plurality of at least partially overcoated layers. When having a plurality of sheet heating elements, the composition, coating thickness, etc. of the resistance heating coating layer provided in each sheet heating element may be the same or different; It is preferable that they be the same because the heat generation characteristics of the bodies will be the same and temperature control will be easier.

The resistance heating coating layers 142a, b are connected to conductive parts 143A, B formed of conductive adhesive tape, and lead wires 144A, B connected to the conductive parts 143A, B. Electricity is supplied by connecting the other end of B to an external power source. Although the resistance heating coating layers 142a and 142b are arranged in parallel, they may be arranged in series, or may be connected to separate external power sources. For example, by arranging them in parallel, the resistance value can be lowered, making it possible to use a lower voltage.Also, even if one of the planar heating elements shorts out, electricity will flow through the other planar heating elements, resulting in heating. can be continued. By arranging them in series, the resistance value can be increased, so that they can be heated with a commonly used 100V power supply.
The conductive parts 143A and 143B can also be formed of conductive paste instead of conductive adhesive tape. When using a conductive paste, it is possible to use one that satisfies the desired properties such as coatability, adhesion, and fixation among those containing conductive particles such as copper and silver.
As the lead wires 144A and 144B, known wires can be used, and for example, metal wires such as copper wire, nickel wire, copper-plated nickel stranded wire, copper-plated aramid fiber, etc. can be used without particular limitation. However, it is preferable to use an aggregate of a plurality of fibers because it collapses and becomes flat due to the pressure during heat fusion in the manufacturing process. Note that the method for supplying electricity to the resistive heat generating coating layers 142a and 142b is not limited, and a known method may be used, and electricity may also be supplied wirelessly.

When using the lead wires 144A, B, the lead wires 144A, B may be led to the outside of the first thermoplastic resin base 11 from different locations, or may be led from the same location. Further, when a temperature sensor such as a thermocouple is sealed in the planar heating element 14, the cord of this sensor may be led to the outside from either a different location or the same location. If a temperature sensor is installed, it is preferably installed within at least one heat transfer material 13a, b.

"How to use the sheet heating device"
FIG. 6 shows how the silicone tube T is heated by the planar heating device of the present invention. Note that there are no limitations on what can be heated by the planar heating device of the present invention.
The planar heating device 101 is the same as the planar heating device 100 of the first embodiment, except that it includes the detachable member 15 (FIG. 6a). The planar heating device 101 can be fixed by the detachable member 15 in a state where the two planar heating elements 14a and 14b are bent to face each other. Examples of the detachable member 15 include a hook-and-loop fastener, a snap button, a magnetic sheet, a hook, a carabiner, and the like.
In the planar heating device 101, deformable heat transfer materials 13a and 13b are installed separately, and two planar heating elements are placed under the heat transfer materials 13a and 13b within a first thermoplastic resin base. are buried far apart. By placing the silicone tube T on top of one of the sheet heating elements (FIG. 6b) and bending it with the first thermoplastic resin base on the outside, it is possible to make the two sheet heating elements 14a and 14b face each other. Yes (Figure 6c). In this state, by deforming the heat transfer materials 13a and 13b according to the shape of the silicone tube T, it is possible to reduce the gap between the silicone tube T and the planar heating device 101 and bring them into close contact (Fig. 6d). ). As a result, the planar heating device 101 can efficiently heat even a thin and flexible object to be heated, such as the silicone tube T, by contacting the object over a wide area without deforming the object. can.

Further, in order to reduce heat radiation to the outside, it is preferable that the sheet heating device 101 is provided with a heat insulating material made of knitted fabric, woven fabric, etc. on its outer circumferential surface during use. In addition, during use, it is preferable to use it horizontally or to suspend it on another object so that the object to be heated is not deformed by the load of the planar heating device 101.

"Second embodiment"
7 and 8 show a schematic diagram and an exploded view of a planar heating device 200, which is a second embodiment. In addition, in the planar heating device 200 which is a second embodiment, the same reference numerals are given to the same members as in the planar heating device 100 which is the first embodiment.
In the planar heating device 200, the heat transfer materials 23a and 23b are made of an elastically deformable material (for example, rubber), and the second thermoplastic resin base 22 has depressions 222a and 222b in advance, and the heat transfer materials 23a, This is the same as the planar heating device 100 of the first embodiment, except that depressions 231a and 231b are formed in advance in b.
The second embodiment of the sheet heating device 200 has a recess formed in the surface that contacts the object to be heated, and the object to be heated can be fitted into this recess, so that the object to be heated can be heated by vibration or the like. can be prevented from shifting.

"Third embodiment"
FIG. 9 shows a schematic diagram of a planar heating device 300 that is a third embodiment.
In the third embodiment of the planar heating device 300, depressions 322a and 322b are formed to correspond to the silicone tube T that is the object to be heated. Thereby, a long object to be heated, such as a silicone tube, can be heated for a longer time.

“Fourth embodiment”
FIG. 10 shows a schematic diagram of a planar heating device 400, which is a fourth embodiment.
In the fourth embodiment of the planar heating device 400, substantially circular depressions 422a and 422b are formed. By arranging a long object to be heated, such as a silicone tube T, in the recesses 422a and 422b in a double spiral shape, the object to be heated can be heated for a long time, and the number of windings allows the object to be heated. You can also adjust the time.

"Other embodiments"
The planar heating devices of the first to fourth embodiments are merely examples of embodiments, and the planar heating device of the present invention is not limited thereto.
For example, similar to the planar heating device 200, although the second thermoplastic resin base has a recess, a plastically deformable material (for example, clay) can be used as the heat transfer material. Further, the number of planar heating elements is not limited to two, but may be one, or three or more.

"Example 1"
A water-based heat-generating paint (Carbo e-Therm, PUR70-350B.01) was coated on paper (Nippon Himoki Trading Co., Ltd., CTN4, thickness 1 mm) to a thickness of 20 μm, and air-dried to a thickness of approximately 5 μm. A coating layer was formed. After drying, two pieces were cut out to a size of 60 mm in length x 40 mm in width.
The two cut out samples were placed horizontally at a distance of 3 cm, and copper tape (Teraoka Seisakusho Co., Ltd., No. 8323) was placed on both horizontal sides on the surface coated with the water-based heat-generating paint. The samples were attached in a width of 5 mm so as to connect them, and one of the copper tapes was attached so as to pass through the back side of the paper to form a conductive part. Polyethylene (hereinafter referred to as PE) resin sheets having a thickness of 200 μm were sandwiched from both sides except for the ends of the conductive portion, and heat-pressed at 5 kN or less for 5 minutes at 130° C. to fuse the conductive portion.
A 150 mm flame-retardant PE coated lead wire was connected to the end of the copper tape by soldering. In addition, the thermocouple part of the fluororesin-coated K-type thermocouple wire (product name, etc.) was installed, and the lead wire connection part and the thermocouple cord were sandwiched from both sides between 500 μm thick PE resin sheets and heated to 130°C. Heat pressing was performed for 5 minutes at a pressure of 5 kN or less to fuse and obtain a first thermoplastic resin base in which a planar heating element was embedded.

A PE resin sheet with a thickness of 200 μm was placed on top of silicone rubber in which two recesses measuring 70 mm long x 45 mm wide x 5 mm deep were lined up horizontally at 1.5 cm intervals, and heat pressed at 130°C for 3 minutes at 5 kN or less. , a second thermoplastic resin substrate having a recessed portion was obtained.
This recess is filled with thermally conductive clay (Tran-Q Clay, NOK Corporation) as a heat transfer material, and a thermocouple fused to the first thermoplastic resin base is embedded in one of the recesses. The sheet heating element of the first thermoplastic resin base is placed on top of the first thermoplastic resin substrate, and heat pressing is performed at 130° C. for 3 minutes at 5 kN or less to fuse the thermoplastic resin substrates together to obtain a sheet heating element. Ta.

・Heating test The planar heating element obtained in Example 1 was bent with the second thermoplastic resin base inside, and a silicone tube (outer diameter 3 mm, inner diameter 1 mm) was placed between the opposing heat transfer materials. Then, by applying pressure manually to deform the heat transfer material, the tube was brought into close contact with the heat transfer material.
Tap water at 20° C. was flowed through the tube at a flow rate of 0.45 ml/min while heating the sheet heating element by adjusting the voltage so that the power consumption was 4.4 W. The length of the heated tube was 50 mm, and the water temperature was measured at a point 20 mm downstream of the planar heating element.

“Comparative Example 1”
A cord heater (Sakaguchi Dentsu Co., Ltd., silicone cord heater, length 1000 mm) was used.
This cord heater was wrapped around a 50 mm long portion of a silicone tube (Kokugo Co., Ltd., polyethylene capillary tube No. 9, outer diameter 3 mm, inner diameter 1 mm) so as to provide the same heating area as the planar heating element of Example 1. .
A heating test was conducted in the same manner as in Example 1, and the water temperature was measured.

-Results In the planar heating element of Example 1, the water temperature stabilized in about 25 minutes after starting heating, and the water temperature after 30 minutes was 47.2°C.
In the cord heater of Comparative Example 1, the water temperature 30 minutes after the start of heating was 41.5°C, and although the power consumption was 4.4 W, which was the same as that of Example 1, it was lower than that of Example 1. The water temperature was also low. This is presumed to be because the outside diameter of the tube is as small as 3 mm, making it difficult to wrap the cord heater around it, creating a gap between the tube and the cord heater, which prevents heat from being transferred efficiently.

Planar heating device 100,200,300,400
First thermoplastic resin base 11
First thermoplastic resin sheet 111
Second thermoplastic resin sheet 112

Second thermoplastic resin base 12, 22
Recessed portions 121a, b, 221a, b
Hollows 222a, b, 322a, b, 422a, b
Heat transfer material 13a, b, 23a, b
Hollows 231a, b

Planar heating element 14a, b
Base material 141a, b
Resistance heating coating layer 142a, b
Conductive part 143A, B
Lead wire 144A, B
Detachable member 15

Silicone tube T

Claims

a first thermoplastic resin base in which a planar heating element is embedded;
a second thermoplastic resin base;
a deformable heat transfer material sealed between the first and second thermoplastic resin bases so as to cover the entire heating area of the planar heating element;
has
The planar heating element includes a base material and a resistance heating coating layer coated on the base material,
The thickness of the second thermoplastic resin base is 50 μm or more and 400 μm or less,
A planar heating device characterized in that the thickness of the base material is twice or more the thickness of the second thermoplastic resin base material.
The planar heating device according to claim 1, wherein the heat transfer material has a Shore E hardness of 1 or more and 50 or less.
The planar heating device according to claim 1 or 2, wherein the base material is paper.
The planar heating device according to claim 1 or 2, wherein the heat transfer material is one or more selected from rubber, clay, gel, and solid oil.
Two or more of the planar heating elements are embedded in the first thermoplastic resin base,
The planar heating device according to claim 1 or 2, wherein the sheet heating device is bendable with the first thermoplastic resin base on the outside.