JP7835095B2 - Insulated containers and insulation systems - Google Patents

Description

This invention relates to a thermal insulation container and a thermal insulation system.

Conventionally, insulated containers with the function of keeping the contents (e.g., beverages) warm have been proposed. For example, an insulated container has been proposed that uses a heating element at the bottom, and by energizing this heating element, it keeps the beverage warm (see Patent Documents 1 and 2).

Japanese Patent Publication No. 2007-312932 Japanese Patent Publication No. 2019-68919

Conventional insulated containers focus on convenience and long-term heat retention, but do not consider heating contents under specific conditions or maintaining a suitable temperature. Therefore, depending on the heating conditions and desired temperature, these containers may not be suitable. For example, in the case of lotions containing many components such as water-soluble and fat-soluble ingredients, gradual heating is preferable; rapid heating can alter the properties of the components. The same applies to beverages consumed by infants; rapid heating can result in unexpectedly high temperatures, or require a long time to cool to a suitable drinking temperature. Furthermore, when maintaining cosmetics at body temperature (e.g., 30-39°C), some heating elements require adjusting the supplied voltage in 0.1V increments, or conversely, in tens of volts, making temperature control difficult.

The objective of this invention is to provide a heat-insulating container and a heat-insulating system that can heat and maintain the contents under conditions suitable for the contents.

The present invention solves the problem through the following means. For ease of understanding, the embodiments of the present invention are denoted by reference numerals, but are not limited thereto. Furthermore, the configurations described with reference numerals may be modified as appropriate, and at least a part of them may be replaced with other components.

The first invention relates to a heat-retaining container comprising: a container body (11) for holding contents; a transparent conductive part (12) provided on at least the outer peripheral surface of the container body and generating heat upon power supply; and a power receiving part (13) electrically connected to the transparent conductive part.

The second invention relates to the heat-retaining container according to the first invention, wherein the surface resistivity of the transparent conductive part is set such that the temperature measured when 15V and 5V voltages are applied to the transparent conductive part for 15 seconds each satisfies the relationship 10°C < (temperature when 15V is applied - temperature when 5V is applied) < 90°C.

The third invention relates to the heat-retaining container according to the second invention, wherein the surface resistivity of the transparent conductive part is set such that the temperature measured when 15V and 5V voltages are applied to the transparent conductive part for 15 seconds each satisfies the relationship 20°C < (temperature when 15V is applied - temperature when 5V is applied) < 45°C.

The fourth invention relates to the heat-retaining container according to the second invention, wherein the surface resistivity of the transparent conductive part is set such that the temperature measured when 15V and 5V voltages are applied to the transparent conductive part for 15 seconds each satisfies the relationship 45°C < (temperature when 15V is applied - temperature when 5V is applied) < 70°C.

The fifth invention relates to a heat-insulating container according to any of the second to fourth inventions, wherein the surface resistivity of the transparent conductive part is 5 to 75 Ω/□.

The sixth invention relates to a heat-insulating container according to any of the first to fourth inventions, wherein the transparent conductive portion includes a resin portion (36) and a metal nanowire (35) disposed in the resin portion.

The seventh invention is a heat-retaining container according to the sixth invention, wherein the metal nanowire is a silver nanowire.

The eighth invention relates to a thermal insulation container according to any of the first to seventh inventions, wherein the container body is a cylindrical shape with a bottom, and the transparent conductive part comprises a transparent conductive sheet (17), a first electrode (18), and a second electrode (19), wherein the first electrode is provided on one side edge in the width direction of the container body of the transparent conductive sheet, and the second electrode is provided on the other side edge in the width direction of the container body of the transparent conductive sheet.

The ninth invention relates to a thermal insulation container according to any of the first to seventh inventions, wherein the container body is a bottomed cylindrical shape, and the transparent conductive portion comprises a transparent conductive sheet (117), a first electrode (118), and a second electrode (119). The transparent conductive sheet is divided into a first conductive portion (117A) and a second conductive portion (117B) by a dividing portion (113) formed from one side edge in the height direction of the container body toward the other side edge, the first conductive portion and the second conductive portion are electrically connected at the other side edge in the height direction of the container body, the first electrode is provided on one side edge in the height direction of the first conductive portion of the container body, and the second electrode is provided on one side edge in the height direction of the second conductive portion of the container body.

The tenth invention relates to the heat-retaining container according to the ninth invention, wherein the first conductive portion and the second conductive portion of the transparent conductive sheet are electrically connected by a common electrode (114) provided on the other side of the container body in the height direction.

The eleventh invention relates to the heat-insulating container according to the tenth invention, wherein the divided portion is formed in a range of 1 to 99% of the length of the transparent conductive sheet in the height direction, starting from one side edge of the transparent conductive sheet in the height direction.

The twelfth invention relates to a thermal insulation system (1) comprising a thermal insulation container according to any of the first to eleventh inventions, and a power supply device (20) that supplies power to the transparent conductive part of the thermal insulation container by wireless power transfer.

According to the present invention, the insulated container and insulated system allow for heating and maintaining the contents under conditions suitable for the contents.

This is a diagram illustrating the configuration of the heat retention system 1 of the first embodiment. This is a perspective view of the container body 11. This is a plan view of the transparent conductive part 12. This is a cross-sectional view of the transparent conductive part 12. This is a schematic diagram showing the manufacturing process of the transparent conductive sheet 17. This is a schematic diagram showing the manufacturing process of the transparent conductive sheet 17. This is a schematic diagram showing the manufacturing process of the transparent conductive sheet 17. This is a diagram illustrating the configuration of the heat retention system 2 of the second embodiment. This is a plan view showing the first configuration of the transparent conductive part 112. This is a plan view showing the second configuration of the transparent conductive part 112. This figure shows the test results of the example and comparative example in Example/Comparative Example No. 1. This diagram shows the relationship between sheet temperature and water temperature. This figure shows the test results of the example and comparative example in Example/Comparative Example No. 2. This figure shows the test results for Example No. 3. This is a plan view showing the configuration of a transparent conductive part 112 with three divided sections 113.

Hereinafter, embodiments of the heat-insulating container and heat-insulating system according to the present invention will be described with reference to the drawings.
All drawings attached to this specification are schematic diagrams, and for ease of understanding, the shape, scale, and aspect ratio of each part have been modified or exaggerated from the actual object. In addition, hatching indicating the cross-section of members has been omitted in the drawings where appropriate.

In this specification, the insulated container 10 (described later) is assumed to be upright as shown in Figure 1, with the width direction (left-right) of the container body being the X (X1-X2) direction and the height direction (up-down) being the Y (Y1-Y2) direction. In this specification, "direction" is also referred to as "side" as appropriate.
Furthermore, in this specification, the act of heating or keeping the contents held in the container body 11 warm is collectively referred to as "insulation." The insulated container and insulation system according to the present invention can not only heat the contents but also keep them warm, or it can perform only one of heating or insulation.

(First Embodiment)
Figure 1 is a diagram illustrating the configuration of the heat retention system 1 of the first embodiment. Figure 2 is a perspective view of the container body 11. Figure 3 is a plan view of the transparent conductive part 12.
As shown in Figure 1, the first embodiment of the heat retention system 1 comprises a heat retention container 10 and a power supply device 20.

The insulated container 10 comprises a container body 11, a transparent conductive part 12, and a power receiving part 13.
The container body 11 is a container for holding contents such as beverages and lotions. As shown in Figure 2, the container body 11 comprises a cylindrical body portion 14 and a cap 15. The upper side Y1 of the body portion 14 is open and has a screw portion (not shown) for attaching the cap 15 detachably. The lower end Y2 of the body portion 14 is closed by a bottom portion 16. In other words, the container body 11 is a cylindrical shape with a bottom.

The transparent conductive part 12 is a transparent heating element that generates heat when power is supplied. The transparent conductive part 12 is provided on the outer surface of the container body 11. As shown in Figure 3, the transparent conductive part 12 comprises a transparent conductive sheet 17, a first electrode 18, and a second electrode 19. The transparent conductive sheet 17 is a laminate comprising a resin layer, a conductive layer, etc., which will be described later. In this embodiment, the transparent conductive sheet 17 is formed to be a vertically elongated rectangle to match the vertically elongated container body 11. That is, the transparent conductive sheet 17 in this embodiment is configured such that the length L1 in the width direction X is less than the length L2 in the height direction Y. Note that Figure 3 shows an example of the shape of the transparent conductive sheet 17. The shape of the transparent conductive sheet 17 is not limited to the rectangular shape shown in Figure 3. The layer structure of the transparent conductive sheet 17 will be described later.

The first electrode 18 and the second electrode 19 are conductive members that apply voltage to the transparent conductive sheet 17. As shown in Figure 3, the first electrode 18 is provided on the left side edge X1 in the width direction X of the transparent conductive sheet 17. The second electrode 19 is provided on the right side edge X2 in the width direction X of the transparent conductive sheet 17. The length L0 shown in Figure 3 represents the distance between the first electrode 18 and the second electrode 19 (hereinafter also referred to as the "electrode distance"). Note that the positions where the first electrode 18 and the second electrode 19 are formed may be reversed left and right.

As shown in Figure 1, the transparent conductive portion 12 is wrapped around the outer circumferential surface of the container body 11. The transparent conductive portion 12 is attached to the outer circumferential surface of the container body 11 via an adhesive layer (not shown). In this embodiment, the first electrode 18 and the second electrode 19 are arranged to overlap in the circumferential direction of the container body 11. That is, the first electrode 18 and the second electrode 19 are arranged to substantially coincide in the width direction X of the heat-insulating container 10. Furthermore, in the transparent conductive sheet 17 wrapped around the outer circumferential surface of the container body 11, the first electrode 18 and the second electrode 19 are electrically insulated by the transparent conductive sheet 17 located on the inside, so the two electrodes do not conduct electricity.

The power receiving unit 13 is a power receiving coil that receives power via the induced magnetic flux generated between it and the power supply device 20 (described later) in the wireless power transfer described later. The power receiving unit 13 is located on the underside of the bottom surface 16 of the container body 11. The power receiving unit 13 is electrically connected to the first electrode 18 and the second electrode 19 via a power receiving circuit (not shown). For example, the positive (+) wire from the power receiving circuit is connected to the first electrode 18, and the negative (-) wire from the power receiving circuit is connected to the second electrode 19. The power received by the power receiving unit 13 is supplied to the first electrode 18 and the second electrode 19 via the power receiving circuit.

The power supply device 20 is a device that wirelessly supplies power to the insulated container 10. The power supply device 20 comprises a power supply mat 21 and a power supply unit 22. The power supply mat 21 is a roughly disc-shaped member on which the insulated container 10 is placed. A power transmission unit 23 is built into the power supply mat 21. The power transmission unit 23 is a power transmission coil that sends power to the power receiving unit 13 of the container body 11 by electromagnetic induction. Note that the method of supplying power from the power supply device 20 to the insulated container 10 is not limited to electromagnetic induction; for example, methods such as magnetic field resonance or electric field coupling may also be used.

The power supply unit 22 is a power supply device that supplies power to the power supply mat 21. The power supply unit 22 is composed of, for example, an AC adapter connected to a household outlet. A power transmission circuit (not shown) is connected between the power transmission unit 23 and the power supply unit 22. The power supplied from the power supply unit 22 is converted to AC power of a predetermined frequency by the power transmission circuit and then supplied to the power transmission unit 23. When the user places the insulated container 10 on the power supply mat 21, power is sent to the power receiving unit 13 by the induced magnetic flux generated between the power transmission unit 23 and the power receiving unit 13. This power is supplied from the power receiving unit 13 to the first electrode 18 and the second electrode 19 via the power receiving circuit (not shown). As a result, the transparent conductive sheet 17 generates heat, keeping the contents held in the insulated container 10 warm.

Next, the layer structure of the transparent conductive part 12 will be described. Figure 4 is a cross-sectional view of the transparent conductive part 12. In Figure 4, the vertical direction of the figure is described as the thickness direction Z. In the thickness direction Z, the upper side of the figure is the Z1 side (front side), and the lower side is the Z2 side (back side). The Z1 side is the side that is attached to the container body 11.

As shown in Figure 4, the transparent conductive sheet 17 in the transparent conductive portion 12 comprises a light-transmitting substrate 31, a hard coat layer 32, a conductive layer 33, and an overcoat layer 34. Note that Figure 4 shows an example of the layer structure of the transparent conductive sheet 17 and is not limited to the example shown in Figure 4. Also, the thickness of each layer in Figure 4 is schematically shown and may differ from the actual thickness.

The light-transmitting substrate 31 is a film that supports the hard coat layer 32 and the conductive layer 33. Examples of resins that can be used to constitute the light-transmitting substrate 31 include polyethylene terephthalate (PET) and cycloolefin polymer (COP). When using a cycloolefin polymer as the light-transmitting substrate 31, it is preferable to provide a hard coat layer (not shown) between the light-transmitting substrate 31 and the conductive layer 33 to improve durability.

The hard coat layer 32 is a resin layer provided on the back side Z2 of the light-transmitting substrate 31. The hard coat layer 32 is light-transmitting and harder than the light-transmitting substrate 31. The resin constituting the hard coat layer 32 may include polymers (cured products, crosslinked products) of polymerizable compounds. The resin may also include solvent-drying resins in addition to polymers of polymerizable compounds. Examples of polymerizable compounds include ionizing radiation polymerizable compounds and/or thermally polymerizable compounds. Among these, ionizing radiation polymerizable compounds are preferred as the polymerizable compound due to their fast curing speed and ease of design. Alternatively, an anti-glare layer may be formed instead of the hard coat layer 32. Furthermore, depending on the layer configuration of the transparent conductive sheet 17, the hard coat layer 32 may be omitted.

The conductive layer 33 is a conductive layer. The conductive layer 33 contains conductive fibers 35 and a light-transmitting resin (resin portion) 36. Note that the conductive layer 33 does not need to contain the light-transmitting resin 36 as long as it contains the conductive fibers 35. The conductive fibers 35 are arranged within the light-transmitting resin 36. In this specification, "conductive fiber" refers to a fiber that is conductive and has a length that is sufficiently longer than its thickness (e.g., diameter). For example, a fiber is generally considered conductive if its length is approximately five times or more its thickness.

It is preferable that multiple conductive fibers 35 are present within the conductive layer 33. The conductive fibers 35 are in contact with each other in the thickness direction (Z direction) of the conductive layer 33 so that electrical conductivity is possible on the Z1 side surface of the conductive layer 33.
In the conductive layer 33, it is preferable that a network structure (mesh structure) is formed in the planar direction (two-dimensional direction) of the conductive layer 33 by the conductive fibers 35 coming into contact with each other. By forming a network structure with the conductive fibers 35, conductive paths can be formed in the planar direction.

The thickness of the conductive layer 33 is preferably less than 300 nm. By making the thickness of the conductive layer 33 less than 300 nm, some of the conductive fibers 35 are exposed on the front surface Z1 of the overcoat layer 34 (described later), thus enabling electrical conductivity with the first electrode 18 and the second electrode 19. If the thickness of the conductive layer 33 is 300 nm or more, the thickness of the light-transmitting resin 36 becomes too thick, causing most of the conductive fibers 35 to be buried in the light-transmitting resin 36, potentially preventing electrical conductivity from being achieved on the front surface Z1 of the overcoat layer 34. When increasing the thickness of the light-transmitting resin 36, a conductive additive may be added to the light-transmitting resin 36.

The surface resistivity (Ω/□) of the conductive layer 33 is set such that the temperature measured when voltages of 15V and 5V are applied between the first electrode 18 and the second electrode 19 (see Figure 3) for 15 seconds each satisfies the following relationship (1).
10°C < (temperature when 15V is applied - temperature when 5V is applied) < 90°C ... (1)

In equation (1) above, the lower limit of the temperature difference is set to 10°C in order to obtain a temperature rise of at least 1°C when a voltage of 1V is applied. If the surface resistivity of the conductive layer 33 is set so that the temperature difference shown in equation (1) (temperature when 15V is applied - temperature when 5V is applied) is less than 10°C, it becomes difficult to obtain a temperature rise of 1°C when a voltage of 1V is applied. Therefore, considering practicality, it is preferable to set the lower limit of the temperature difference in equation (1) to 10°C. On the other hand, the upper limit of the temperature difference in equation (1) is set to 90°C in order to avoid a temperature rise of 8°C or more when a voltage of 1V is applied. If the surface resistivity of the conductive layer 33 is set in a range where the temperature difference shown in equation (1) exceeds 90°C, the temperature will change too quickly in response to the application of voltage. Therefore, considering safety, it is preferable to set the upper limit of the temperature difference in equation (1) to less than 90°C. Note that the temperature difference shown in formula (1) above (temperature when 15V is applied - temperature when 5V is applied) is assumed to be measured under conditions of 20-30°C and 30-70% humidity.

When heating and maintaining a liquid such as water or lotion at a temperature of approximately 30-45°C, which has minimal impact even when it comes into direct contact with the human body, it is preferable to set the surface resistivity of the conductive layer 33 to satisfy the following relationship (2).
20°C < (temperature when 15V is applied - temperature when 5V is applied) < 45°C ... (2)
As described in the examples below, in cases where a liquid such as water or lotion is heated and kept at approximately 30-39°C, which is about the same as human body temperature, it is preferable to set the surface resistivity of the conductive layer 33 to satisfy the following relationship (2a).
20°C < (temperature when 15V is applied - temperature when 5V is applied) < 39°C ... (2a)
When heating and maintaining the temperature of coffee, tea, etc., at a comfortable drinking temperature of around 55°C, it is preferable to set the surface resistivity of the conductive layer 33 to satisfy the following relationship (3).
45°C < (temperature when 15V is applied - temperature when 5V is applied) < 70°C ... (3)
When stably maintaining the contents at a low temperature of approximately 15 to 25°C, it is preferable to set the surface resistivity of the conductive layer 33 to satisfy the following relationship (4).
10°C < (temperature when 15V is applied - temperature when 5V is applied) < 20°C ... (4)
When you want to boil water in a short amount of time, it is preferable to set the surface resistivity of the conductive layer 33 to satisfy the following relationship (5).
65°C < (temperature when 15V is applied - temperature when 5V is applied) < 90°C ... (5)
Specific examples of cases where the above formulas (1) to (5) are applied to determine the surface resistivity of the conductive layer 33 will be explained in the embodiments described later.

The surface resistivity (Ω/□) of the conductive layer 33 can be adjusted by the amount of conductive fibers 35 arranged in the conductive layer 33. If the fiber diameter, fiber length, and material of the conductive fibers 35 are the same, the surface resistivity can be increased by reducing the amount of conductive fibers 35. Conversely, the surface resistivity can be decreased by increasing the amount of conductive fibers 35.

The fiber diameter of the conductive fiber 35 is preferably 100 nm or less. If the fiber diameter of the conductive fiber 35 is 100 nm or less, the increase in the haze value of the transparent conductive sheet 17 can be suppressed, and there is no risk of a decrease in light transmittance. The lower limit of the fiber diameter of the conductive fiber 35 is preferably 3 nm or more, or 5 nm or more, in order to maintain a stable shape and ensure the conductivity of the conductive layer 33. The upper limit of the fiber diameter of the conductive fiber 35 is more preferably 50 nm or less, or 30 nm or less, from the viewpoint of ensuring transparency. A more preferable range for the fiber diameter of the conductive fiber 35 is 7 nm to 25 nm.

The fiber length of the conductive fiber 35 is preferably 1 μm or more. If the fiber length of the conductive fiber 35 is 1 μm or more, a conductive layer 33 with sufficient conductive performance can be formed, and aggregation can be suppressed, thus preventing an increase in haze value or a decrease in light transmittance. The upper limit of the fiber length of the conductive fiber 35 may be 100 μm or less, 30 μm or less, or 20 μm or less. The lower limit of the fiber length of the conductive fiber 35 may be 3 μm or more, or 10 μm or more.

As the conductive fiber 35, it is preferable to use a metal fiber. As the metal fiber, for example, metal nanowires composed of stainless steel, Ag, Cu, Au, Al, Rh, Ir, Co, Zn, Ni, In, Fe, Pd, Pt, Sn, Ti, or alloys thereof are preferred. Among metal nanowires, silver nanowires are particularly preferred from the viewpoint of high electrical and thermal conductivity. When silver nanowires are used as the conductive fiber 35, if the surface resistivity of the transparent conductive part 12 is 5 Ω/□ or higher, the light transmittance can be 80% or higher. Furthermore, if the surface resistivity of the transparent conductive part 12 is 30 Ω/□, the light transmittance can be approximately 90%. As the metal fiber, for example, fibers produced by drawing or cutting the above metals into thin, long strands can be used. One or more types of such metal fibers can be used.

When using silver nanowires as metallic fibers, they can be synthesized by liquid-phase reduction of a silver salt (e.g., silver nitrate) in the presence of a polyol (e.g., ethylene glycol) and poly(vinylpyrrolidone). Mass production of uniformly sized silver nanowires can be achieved, for example, by the methods described in Xia, Y. et al., Chem. Mater. (2002), 14, 4736-4745 and Xia, Y. et al., Nanoletters (2003) 3(7), 955-960.

There are no particular restrictions on the manufacturing methods for metal nanowires; for example, known methods such as liquid-phase and gas-phase methods can be used. Similarly, there are no particular restrictions on the specific manufacturing method; known manufacturing methods can be used. For example, for manufacturing silver nanowires, reference can be found in Adv, Mater., 2002, 14, 833-837; Chem. Mater., 2002, 14, 4736-4745, etc.

The light-transmitting resin 36 covers the conductive fibers 35 to prevent them from falling off the conductive layer 33 and to improve the durability and abrasion resistance of the conductive layer 33. The light-transmitting resin 36 is not particularly limited as long as it is a resin with light-transmitting properties, but examples of light-transmitting resins include polymers of polymerizable compounds and plastic resins.

The overcoat layer 34 is a resin layer for protecting the conductive layer 33 and is provided on the front side Z1 of the conductive layer 33. The overcoat agent used for the overcoat layer is not particularly limited, and a general-purpose overcoat agent can be used. Furthermore, depending on the layer configuration of the transparent conductive sheet 17, the overcoat layer 34 may be omitted.

A first electrode 18 and a second electrode 19 are formed on the front side Z1 of the conductive layer 33, either the overcoat layer 34 or the conductive layer 33 without the overcoat layer 34. The first electrode 18 and the second electrode 19 can be formed, for example, by a commonly known method such as direct coating using screen printing, inkjet printing, or a dispenser, or by sintering after drying. The length of the first electrode 18 and the second electrode 19 in the width direction X is, for example, about 0.01 mm to 10 mm.

The transparent conductive sheet 17 can be directly attached to the container body 11 via an adhesive layer (OCA), but for example, a protective substrate may be attached to the front side Z1 of the transparent conductive sheet 17 via an adhesive layer (OCA), and then attached to the container body 11 via this substrate. Alternatively, the transparent conductive sheet 17 may be sandwiched between a pair of plastics, glass, etc., to form a sandwich-structured container.

Next, the manufacturing method of the transparent conductive sheet 17 will be described. Figures 5 to 7 are schematic diagrams showing the manufacturing process (A) to (F) of the transparent conductive sheet 17. Note that the manufacturing method of the transparent conductive sheet 17 described below is just one example, and the transparent conductive sheet 17 can also be manufactured by other methods.

First, as shown in Figure 5(A), the resin layer composition is applied to the first surface 31A of the light-transmitting substrate 31 and dried to form a coating film 39 of the resin layer composition. If the light-transmitting substrate 31 has a base layer on one side, the first surface 31A is preferably the surface of the base layer. Known methods for applying the resin composition include spin coating, dip coating, spray coating, slide coating, bar coating, roll coating, gravure coating, and die coating.

Next, as shown in Figure 5(B), the coating film 39 is irradiated (or heated) with ionizing radiation I such as ultraviolet light to polymerize (crosslink) the polymerizable compound, thereby curing the coating film 39 and forming a hard coat layer (resin layer) 32.

When using ultraviolet light as the ionizing radiation to cure the coating film 39, ultraviolet light emitted from ultra-high pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, carbon arcs, xenon arcs, metal halide lamps, etc., can be used. Furthermore, the wavelength range of ultraviolet light can be 190 to 380 nm. Specific examples of electron sources include various electron beam accelerators such as Cockcroftwald type, Van de Graft type, resonant transformer type, insulated core transformer type, linear type, Dynamitron type, and high-frequency type. After forming the hard coat layer 32, the hard coat layer 32 is statically neutralized as needed. For static neutralization, for example, a voltage-applied static neutralizer (product name "SJ-H156A," manufactured by Keyence Corporation) can be used.

After the hard coat layer 32 is statically discharged, a conductive fiber-containing composition containing conductive fibers 35 and a dispersion medium is applied to the second surface 31B of the light-transmitting substrate 31 and dried to arrange multiple conductive fibers 35 on the second surface 31B of the light-transmitting substrate 31, as shown in Figure 6(C). The conductive fiber-containing composition may also contain a resin component consisting of a thermoplastic resin or a polymerizable compound, in addition to the conductive fibers 35 and the dispersion medium.

After arranging multiple conductive fibers 35 on the second surface 31B of the light-transmitting substrate 31, a light-transmitting resin composition containing a polymerizable compound and a solvent is applied and dried to form a coating film 30 of the light-transmitting resin composition, as shown in Figure 6(D). The light-transmitting resin composition contains a polymerizable compound and a solvent, but polymerization initiators and reaction inhibitors may also be added as needed.

Next, as shown in Figure 7(E), the coating film 30 is irradiated with ionizing radiation I, such as ultraviolet light, to polymerize (crosslink) the polymerizable compound, thereby curing the coating film 30 and forming a light-transmitting resin 36. This forms a conductive layer on the second surface 31B of the light-transmitting substrate 31. Next, as shown in Figure 7(F), an overcoat layer 34 is formed on the second surface 33B of the conductive layer 33. This results in a transparent conductive sheet 17 comprising the light-transmitting substrate 31, hard coat layer 32, conductive layer 33, and overcoat layer 34.

According to the first embodiment of the heat-insulating container 10, by setting the surface resistivity of the transparent conductive part 12 (transparent conductive sheet 17) to satisfy the relationships shown in the aforementioned formulas (1) to (5), the contents held in the heat-insulating container 10 can be heated and maintained at a temperature suitable for the contents and the conditions for heating them. The specific effects of setting the surface resistivity of the transparent conductive part 12 to each of the above formulas will be explained in detail in Example/Comparative Example No. 1 and Example/Comparative Example No. 2 below.

In the first embodiment, the insulated container 10 has a transparent conductive part 12 that generates heat when electricity is supplied, which is provided on the outer surface of the container body 11. Therefore, compared to the conventional method of heating the container body from the bottom, the area of the heated region can be increased. This configuration reduces temperature variations in the contents held inside the container, resulting in superior temperature uniformity of the contents. Furthermore, because the transparent conductive part 12 is transparent, the contents can be kept warm without compromising the design of printed characters, patterns, or designs on the outer surface of the container body 11.

In the first embodiment of the heat-retaining container 10, since metal nanowires are used as conductive fibers 35 arranged in the transparent conductive portion 12, the surface resistivity can be adjusted more appropriately. In this embodiment, since silver nanowires are used as metal nanowires, good conductivity and thermal conductivity can be obtained in the transparent conductive portion 12. Furthermore, when silver nanowires are used as conductive fibers 35, if the surface resistivity of the transparent conductive portion 12 is 3Ω/□ or higher, the light transmittance can be set to 80% or higher. As mentioned above, when keeping the contents of the heat-retaining container 10, such as water or cosmetics, at approximately 30-39°C, which is about the same as body temperature, the light transmittance can be set to 90% or higher by setting the surface resistivity of the conductive layer 33 (transparent conductive portion 12) to 20Ω/□ or higher. If the light transmittance of the heat-retaining container 10 is 80%, the state of the contents placed inside the container body 11 can be easily checked.

Furthermore, to warm 30 to 200 cc of water to body temperature, it is preferable to set the surface resistivity of the conductive layer 33 to 5 Ω/□ or more and 75 Ω /□ or less. Also, from the viewpoint of controlling the temperature of the transparent conductive sheet 17 within an appropriate range, it is preferable to set the surface resistivity of the conductive layer 33 to 10 Ω /□ to 70 Ω /□ , and more preferably to 20 Ω /□ to 50 Ω /□ . When it is desirable to warm the water held in the insulated container 10 quickly or when the capacity is large, it is preferable to set the surface resistivity of the conductive layer 33 to 5 Ω/□ to 30 Ω/□. For example, if the surface resistivity of the conductive layer 33 is 100 Ω/□ or more, heating will not progress easily even when a voltage of 15 V is applied between the electrodes.

Considering the case where a metal sheet is provided as a heating element on the outer surface of the container body 11, it is considered difficult to control the temperature to a level of approximately 30-45°C, or in particular, approximately 30-39°C, which is close to human body temperature, because metal has low surface resistivity and its temperature rises rapidly in response to voltage changes. Furthermore, while a certain degree of transparency can be ensured when a mesh-like metal is used as the heating element, it is not possible to prevent the occurrence of moiré patterns. In contrast, in the heat-retaining container 10 of the first embodiment, the surface resistivity of the conductive layer 33 can be appropriately adjusted. For example, by setting the surface resistivity to approximately 30 Ω/□, stable heat retention of approximately 30-39°C, which is close to human body temperature, can be achieved. Furthermore, it is possible to suppress the occurrence of moiré patterns while ensuring sufficient light transmittance.

In the first embodiment of the heat-insulating container 10, a first electrode 18 is provided on one side edge in the width direction X of the transparent conductive sheet 17, and a second electrode 19 is provided on the other side edge, so that almost the entire surface of the transparent conductive sheet 17 can be used as a heating element. In addition, the process of forming each electrode on the transparent conductive sheet 17 can be simplified.
According to the first embodiment of the heat retention system 1, the power supply device 20 can wirelessly supply power to the heat retention container 10. As a result, there is no need to install a battery or other power source in the heat retention container 10, thus simplifying the configuration and reducing the weight.

(Second Embodiment)
Next, the second embodiment of the heat retention system 2 will be described. In the description and drawings of the second embodiment, components equivalent to those in the first embodiment are given the same reference numerals or the same reference numerals at the end (last two digits) as in the first embodiment, and redundant explanations are omitted as appropriate.

The second embodiment differs from the first embodiment in the configuration of the transparent conductive portion 112 that constitutes the heat-retaining container 110. The first and second configurations of the transparent conductive portion 112 will be described below.

(First configuration / transparent conductive part 112)
Figure 8 is a diagram illustrating the configuration of the heat retention system 2 of the second embodiment. Figure 9 is a plan view showing the first configuration of the transparent conductive part 112.
As shown in Figure 8, in the second embodiment of the heat retention system 2, the heat retention container 110 is provided with a first electrode 118 and a second electrode 119 on the lower side Y2 in the height direction Y. In the transparent conductive part 112 of the second embodiment, the arrangement of the first electrode 118 and the second electrode 119 is the same in the first and second configurations. Therefore, in the description of the second configuration described later, the overall illustration and explanation of the heat retention system 2 will be omitted.

As shown in Figure 9, in the transparent conductive portion 112 of the first configuration, the transparent conductive sheet 117 is divided into a first conductive portion 117A and a second conductive portion 117B by a dividing portion 113 formed from the lower side Y2 (one side edge) to the upper side Y1 (the other side edge) in the height direction Y. In the transparent conductive sheet 117 of the first configuration, the first conductive portion 117A and the second conductive portion 117B are electrically insulated at the dividing portion 113. The length L3 in the width direction X of the dividing portion 113 is, for example, 0.03 mm to 1 mm.

The first conductive portion 117A and the second conductive portion 117B are electrically connected at a common electrode 114 provided on the side edge of the upper Y1. That is, the first conductive portion 117A and the second conductive portion 117B are electrically connected at the side edge of the upper Y1. A first electrode 118 is provided on the side edge of the lower Y2 of the first conductive portion 117A. Furthermore, a second electrode 119 is provided on the side edge of the lower Y2 of the second conductive portion 117B.

In the first configuration of the second embodiment, when a voltage is applied between the first electrode 118 and the second electrode 119, and a current is flowed, for example, from the first electrode 118 to the second electrode 119, the current flows upward Y1 from the first electrode 118 through the first conductive part 117A. This current then flows downward Y2 from the second conductive part 117B via the common electrode 114, reaching the second electrode 119. Therefore, in the transparent conductive part 112 of the second embodiment (first configuration), the contents held in the heat-retaining container 110 can be kept warm, similar to the transparent conductive part 12 of the first embodiment described above.

(Second configuration / Transparent conductive part 112)
Next, the transparent conductive portion 112 of the second configuration will be described. Figure 10 is a plan view showing the second configuration of the transparent conductive portion 112. As shown in Figure 10, in the transparent conductive portion 112 of the second configuration, the transparent conductive sheet 117 is divided into a first conductive portion 117A and a second conductive portion 117B by a dividing portion 113 formed from the lower side Y2 to the upper side Y1 in the height direction Y. In the transparent conductive portion 112 of the second configuration, the first conductive portion 117A and the second conductive portion 117B are electrically insulated at the position of the dividing portion 113. A first electrode 118 is provided on the lower side Y2 edge of the first conductive portion 117A. A second electrode 119 is provided on the lower side Y2 edge of the second conductive portion 117B.

In the second configuration of the transparent conductive portion 112, the length L5 in the height direction Y of the divided portion 113 is set to a range of 30 to 100% of the length L4 from the lower side edge Y2 of the transparent conductive sheet 117 to the upper side edge Y1 of the transparent conductive sheet 117. Preferably, the length L5 of the divided portion 113 is set to a range of 60 to 100%, more preferably 80 to 100%, of the length L4 of the transparent conductive sheet 117. In the second configuration of the transparent conductive portion 112, the first conductive portion 117A and the second conductive portion 117B are not divided in the region Y1 above the divided portion 113 (hereinafter also referred to as the "conductive region 117H"), and are electrically conductive. That is, the first conductive portion 117A and the second conductive portion 117B are electrically conductive at the upper side edge Y1.

In the second configuration of the second embodiment, when a voltage is applied between the first electrode 118 and the second electrode 119, and a current is flowed, for example, from the first electrode 118 to the second electrode 119, the current flows upward Y1 from the first electrode 118 through the first conductive portion 117A. This current then flows downward Y2 from the second conductive portion 117B, via the common electrode 114 and the conductive region 117H, and reaches the second electrode 119. Therefore, in the transparent conductive portion 112 (second configuration) of the second embodiment, the contents held in the heat-retaining container 110 can be kept warm, similar to the transparent conductive portion 12 of the first embodiment described above.

The transparent conductive section 112 of the second configuration offers superior temperature uniformity compared to conventional heat-retaining containers that heat from the bottom. While Figure 10 describes an example where a common electrode 114 is provided on the upper Y1 of the transparent conductive sheet 117, the common electrode 114 may be omitted depending on the ratio of L5 to L4.

In the second embodiment of the insulated container 110, the first electrode 118 and the second electrode 119 of the transparent conductive part 112 (first and second configurations) are located on both side edges in the height direction Y of the container body 11. Therefore, each electrode becomes less conspicuous and the design is improved. Furthermore, the insulated container 110 of the second embodiment also achieves the same effects as the first embodiment described above.

Next, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited in any way to the following examples. In the following examples and comparative examples, the components described in the embodiments above will be referred to by the same names (for example, "transparent conductive part"), but the reference numerals will be omitted.

(Example/Comparative Example No. 1)
First, as Example/Comparative Example No. 1, we will explain the evaluation of heating and heat retention using a transparent conductive part.
Eight transparent conductive sheets (150 mm x 150 mm) were prepared as test sample sheets, each having a conductive layer with a surface resistivity of 3 Ω/□ (Comparative Example 1), 5 Ω/□ (Example 1), 10 Ω/□ (Example 2), 20 Ω/□ (Example 3), 30 Ω/□ (Example 4), 50 Ω/□ (Example 5), 75 Ω/□ (Example 6), and 100 Ω/□ (Comparative Example 2). Each sheet was then processed to 100 mm x 100 mm.

The layer structure of each sample sheet, from the front side Z1 to the back side Z2 (see Figure 4), consisted of a conductive layer (film thickness 100 nm), a light-transmitting substrate (film thickness 38 μm), and a hard coat layer (film thickness 1.5 μm). The conductive layer contained silver nanowires (conductive fibers) and a light-transmitting resin. A PET film ("U48," manufactured by Toray Industries, Inc.) was used as the light-transmitting substrate.

Silver paste was applied to both side edges in the width direction (X direction) of each sample sheet by screen printing in an 8 mm width, and then dried at 130°C for 30 minutes to form two electrodes corresponding to the first and second electrodes. One of the two electrodes was designated as the positive electrode, and the other as the negative electrode. In Example/Comparative Example No. 1, the electrode arrangement of each sample sheet is the same as in the first embodiment. That is, the electrodes are provided on one side edge and the other side edge in the width direction of the transparent conductive sheet, respectively.

Examples 1 to 6 are sample sheets in which the temperature measured when 15V and 5V voltages are applied between the two electrodes for 15 seconds each satisfies the relationship shown in equation (1): 10°C < (temperature when 15V is applied - temperature when 5V is applied) < 90°C. On the other hand, Comparative Examples 1 and 2 are sample sheets in which the temperature measured when 15V and 5V voltages are applied between the two electrodes for 15 seconds each does not satisfy the relationship in equation (1). In Figure 11 (described later), "temperature at 15V - 5V" represents the temperature when 15V is applied - the temperature when 5V is applied.

For each sample sheet, alligator clips were attached to each of the two electrodes, and voltages of 5V, 10V, and 15V were applied using a DC regulated power supply ("TEXIO PW36-1.5ADP," manufactured by TEXIO Technology Corporation). The surface temperature of the Z2 region on the back of each sample sheet was then measured using a thermographic camera ("FLIR Ex E4," manufactured by FLIR Systems).

As part of Evaluation 1, voltages of 5V, 10V, and 15V were applied to each sample sheet in an environment with a room temperature of 23°C. The time (s: seconds) required for the surface temperature to reach 39°C after the start of voltage application was measured. Evaluation 1 is a test to determine whether water can be heated and maintained at 39°C by applying a relatively easy-to-handle voltage of around 5-15V for a few seconds to a dozen seconds. Each sample sheet was fixed at its upper end in the height direction Y (see Figure 3), and the voltage was applied with the entire sheet almost suspended in the air. After each temperature measurement at each voltage, each sample sheet was allowed to cool naturally until its surface temperature reached the same room temperature of 23°C.

As part of evaluation 2, the light transmittance of each sample sheet was measured using a visible light transmittance meter. Evaluation 2 was performed without applying any voltage to each sample sheet.
For evaluation 3, the appearance of each sample sheet was observed. Specifically, a white sheet was placed in the background of each sample sheet, and the degree of yellowness was observed visually. A "×" indicated a yellowish appearance, a "△" indicated a slightly yellowish appearance, and a "〇" indicated a neutral appearance with almost no yellowness. Evaluation 3 was observed without applying voltage to each sample sheet.

Figure 11 shows the test results for each of the above evaluation items for each sample sheet of Examples 1-6 and Comparative Examples 1 and 2. Figure 11 shows the test results for Example and Comparative Example No. 1. In Figure 11, the blank items in Evaluation 1 indicate the case where the temperature did not reach 39°C even after 30 seconds from the application of voltage.

As shown in Figure 11, the sample sheets of Examples 1 to 6, whose surface resistivity satisfies the relationship 10°C < (temperature at 15V application - temperature at 5V application) < 90°C shown in equation (1), were found to be able to be heated and maintained at a voltage range of approximately 5 to 15V for a time range of several seconds to over ten seconds, and both light transmittance and appearance were good. On the other hand, while the sample sheets of Comparative Examples 1 and 2 both showed good light transmittance (evaluation 2), it became clear that temperature control was difficult at voltages of approximately 5 to 15V. For example, the sample sheet of Comparative Example 1 showed a steep temperature rise in response to voltage changes, raising concerns that the contents held inside a container would be rapidly heated if attached to it. Furthermore, the sample sheet of Comparative Example 1 also had an undesirable appearance. The sample sheet of Comparative Example 2 was found to be almost impossible to heat or maintain at voltages of approximately 5 to 15V.

In Example/Comparative Example No. 1, an example was described in which the transparent conductive sheet was 100 mm long x 100 mm wide. However, the heating performance of the transparent conductive sheet differs depending on the electrode distance L0 (see Figure 3). When the transparent conductive sheet is 50 mm long x 100 mm wide, the "15V-5V temperature" in Examples 1 to 6 shown in Figure 11 shifts to a higher temperature overall compared to the case where it is 100 mm long x 100 mm wide. Also, when the transparent conductive sheet is 200 mm long x 100 mm wide, the "15V-5V temperature" in Examples 1 to 6 shown in Figure 11 shifts to a lower temperature overall compared to the case where it is 100 mm long x 100 mm wide. Thus, even when the electrode distance changes, by setting the surface resistivity of the transparent conductive sheet to satisfy the relationship of equations (1) to (5) described above, according to the contents held in the heat-insulating container and the heating conditions, the same results as in Examples 1 to 6 can be obtained. The same applies to point 2.

(Example/Comparative Example No. 2)
Next, as Example/Comparative Example No. 2, we will describe the evaluation of a heat-insulating container in which a transparent conductive part is attached to the container body.
For the transparent conductive parts used in the test, the same transparent conductive parts from Examples 1 to 6 and Comparative Examples 1 and 2 as in Example/Comparative Example No. 1 were used. That is, in Example/Comparative Example No. 2, the electrode arrangement of each transparent conductive part is the same as in the first embodiment. In Example/Comparative Example No. 2, eight insulated containers (hereinafter also referred to as "sample containers"), each with a transparent conductive part from Examples 1 to 6 and Comparative Examples 1 and 2 attached to the container body (a transparent glass screw-cap bottle described later), are also referred to as Examples 1 to 6 and Comparative Examples 1 and 2.

Eight transparent glass screw-cap vials ("9-852-09 Labran Screw-Cap Vial 50ml," manufactured by AS ONE Corporation) were prepared as the main containers. The front side (Z1 side) of each transparent conductive part was attached to the outer surface of these containers using a 15 μm thick transparent adhesive ("8146-2," manufactured by 3M Japan Ltd.) to create the sample containers. Specifically, the transparent conductive part was attached to the area from the top Y1 of the container body up to approximately 60 mm, so that more than 80% of the outer surface of the container body was covered by the transparent conductive part. The remaining portion of the transparent conductive part (approximately 40 mm) was extended upwards. The extended portion of the transparent conductive part was not in contact with the container body, and parts of the two electrodes were exposed. Water was poured into the containers to a level equivalent to 90% of their capacity. The water temperature was set to room temperature (23°C).

For each sample container, alligator clips were attached to the two electrodes of the transparent conductive section, and voltages of 5V, 10V, and 15V were applied using a DC stabilized power supply ("TEXIO PW36-1.5ADP," manufactured by TEXIO Technology Corporation). The surface temperature of each sample container was then measured using a thermographic camera ("FLIR Ex E4," manufactured by FLIR Systems). The surface temperature of the sample container can be considered as the temperature of the water contained within the container.

Evaluation 4 involved applying voltages of 5V, 10V, and 15V to the transparent conductive part of each sample container under a room temperature of 23°C. The time (m: minutes, h: hours) required for the water temperature inside the sample container to reach 39°C was measured from the start of voltage application. Each sample container was allowed to cool naturally until its surface temperature returned to room temperature (23°C) after each temperature measurement at each voltage.

Furthermore, there is a correlation between the surface temperature of the transparent conductive part heated by the application of voltage and the temperature of the water in the container. Figure 12 shows the relationship between the sheet temperature and the water temperature. Specifically, Figure 12 shows the relationship between the sheet temperature (temperature of the transparent conductive part) and the temperature of the water in a sample container to which a 15V voltage is applied, with a transparent conductive part with a surface resistivity of 11.5 Ω/□ attached. As shown in Figure 12, the temperature of the water held in the sample container is about 10°C lower than the temperature of the transparent conductive part. This correlation is thought to remain the same even if the surface resistivity of the transparent conductive part changes.

For evaluation level 5, the appearance (visual characteristics) of the water in each sample container was observed. Specifically, each sample container filled with water was visually inspected to observe the degree of yellowness in the water. A "△" indicated that the water inside had a yellowish tint, while a "〇" indicated that the water was neutral and the yellowness was barely noticeable. Evaluation level 5 was observed without applying voltage to the transparent conductive part of each sample container.

As part of evaluation 6, the safety/component stability when water was added to each sample container and heated was observed. A voltage of 15V was applied to each sample container containing water for 24 hours. If the water temperature reached 50°C or higher, it was marked as "△", and if the water temperature was maintained below 50°C, it was marked as "○".
As part of evaluation 7, we observed the efficiency during heating. When a voltage of 15V was applied to each sample container containing water, a "△" was given if it took more than 15 minutes to heat the water to 39°C, and a "○" was given if the water could be heated to 39°C in less than 15 minutes.

The test results for each of the above evaluation items for the sample containers in Examples 1-6 and Comparative Examples 1 and 2 are shown in Figure 13. Figure 13 shows the test results for Example and Comparative Example No. 2. In Figure 13, the blank item for Evaluation 4 indicates that the temperature did not reach 39°C even after 10 hours from the application of voltage.

As shown in Figure 13, the sample containers of Examples 1 to 6, whose surface resistivity of the transparent conductive portion satisfies the relationship 10°C < (temperature at 15V application - temperature at 5V application) < 90°C shown in equation (1), were found to be able to be heated and maintained at a voltage range of approximately 5 to 15V for a time range of several minutes to several hours, and their appearance was also good. By appropriately selecting the sample containers of Examples 1 to 6, it becomes possible to heat and maintain the contents at the optimal temperature when heating the contents under specific conditions or when maintaining the contents at a temperature suitable for the contents, as will be described later.

Furthermore, it was found that the items 5 to 7 in evaluations for the sample containers of Examples 1 to 6 were all within a practical range. Since evaluations 6 and 7 have a trade-off relationship, more favorable results can be obtained by appropriately selecting the surface resistivity of the transparent conductive part depending on the conditions for heating the contents and how to set the appropriate temperature for the contents.

When warming and maintaining lotions and other similar products at approximately 30-39°C, which is close to body temperature, it is preferable to set the surface resistivity of the transparent conductive part to satisfy the relationship shown in formula (2a): 20°C < (temperature when 15V is applied - temperature when 5V is applied) < 39°C, as in Example 4 or 5. By setting the surface resistivity of the transparent conductive part to satisfy the relationship shown in formula (2a), not only can the lotion be maintained at approximately 30-39°C, which is close to body temperature, but the lotion can also be warmed gradually, thereby suppressing changes in the components it contains. In the case of lotions, gradual warming can improve the dispersibility of the components, so improvements in beauty and moisturizing effects can be expected. Furthermore, by maintaining the lotion at approximately body temperature, resistance to the lotion can be reduced for users with sensitive skin. Moreover, even in the case of beverages consumed by infants, rapid heating is avoided, which prevents the beverage from becoming unexpectedly hot without the user noticing, and prevents it from taking a long time to cool down to a drinkable temperature.
Furthermore, when heating and maintaining the temperature of liquids such as water and cosmetics to around 30-45°C, which has minimal impact even when directly touching the human body, the surface resistivity of the conductive layer 33 should be set to satisfy the relationship shown in equation (2): 20°C < (temperature when 15V is applied - temperature when 5V is applied) < 45°C.

When heating and maintaining the temperature of beverages such as coffee or tea at a comfortable 55°C, it is preferable to set the surface resistivity of the transparent conductive part to satisfy the relationship shown in formula (3): 45°C < (temperature when 15V is applied - temperature when 5V is applied) < 70°C, as in Example 2 or 3. By setting the surface resistivity of the transparent conductive part to satisfy the relationship shown in formula (3), beverages such as coffee or tea can be heated more efficiently and in a shorter time. Furthermore, the beverage can be maintained at a temperature of approximately 55°C by applying a relatively easy-to-handle voltage of around 10-15V.

Furthermore, even when the surface resistivity of the transparent conductive part is set to satisfy the relationship shown in equation (3), the temperature can be raised to approximately 30-39°C, which is roughly the same as human body temperature, by shortening the voltage application time. Thus, even when the surface resistivity of the transparent conductive part is set to satisfy the relationship shown in equation (3), it is possible to raise the temperature to a suitable level for the contents by adjusting the voltage application time.

When stably maintaining the temperature of contents (e.g., food) at a low temperature of approximately 15-25°C, it is preferable to set the surface resistivity of the transparent conductive part to satisfy the relationship shown in equation (4): 10°C < (temperature when 15V is applied - temperature when 5V is applied) < 20°C, as in Example 6. Setting the surface resistivity of the transparent conductive part to satisfy the relationship shown in equation (4) allows for a more gradual heating of the contents, thereby more effectively suppressing changes in the contents' components. Furthermore, the contents can be stably maintained at a voltage of approximately 15V.

When you want to boil water in a short time, it is preferable to set the surface resistivity of the transparent conductive part so that it satisfies the relationship shown in equation (5): 65°C < (temperature when 15V is applied - temperature when 5V is applied) < 90°C, as in Example 1. By setting the surface resistivity of the transparent conductive part to satisfy the relationship shown in equation (5), water can be boiled in an even shorter time.

(Example No. 3)
Next, as Example No. 3, we will describe the evaluation of the second configuration of the transparent conductive part 112 (second embodiment).
Six transparent conductive sheets (150 mm x 150 mm) with a conductive layer having a surface resistivity of 10 Ω/□ were prepared as test sample sheets, and each was processed to 100 mm x 100 mm. The layer structure, materials, film thickness, etc. of each sample sheet were the same as those of Example/Comparative Example No. 1 described above.

Silver paste was applied to both side edges in the height direction (Y direction) of each sample sheet in an 8 mm width by screen printing, and then dried at 130°C for 30 minutes to form two electrodes corresponding to the first and second electrodes. One of the two electrodes was designated as the positive electrode, and the other as the negative electrode. In Example/Comparative Example No. 3, the electrode arrangement of each sample sheet is the same as the second configuration of the second embodiment. That is, the electrodes are provided on one side edge and the other side edge in the height direction of the transparent conductive sheet. After preparing the sample sheets, as shown in Figure 10, a cut with a width of 0.5 mm was made in the center of the width direction X of the transparent conductive sheet, from the lower side Y2 to the upper side Y1 in the height direction Y, to form a divided section. The length L5 of the divided section (see Figure 10) was set to 99%, 75%, 65%, 50%, 35%, and 1% of the length L4 of the transparent conductive sheet (hereinafter also referred to as the "divided section length ratio"), and a total of six transparent conductive sections were prepared.

Six transparent glass screw-cap vials ("9-852-09 Labran Screw-Cap Vial 50ml," manufactured by AS ONE Corporation) were prepared as the container bodies. The front side (Z1 side) of each transparent conductive part was attached to the outer surface of these container bodies using a 15 μm thick transparent adhesive ("8146-2," manufactured by 3M Japan Ltd.) to create the sample containers (Examples 7-12). Specifically, the transparent conductive part was attached to the area from the upper Y1 to approximately 60 mm of the container body, so that more than 80% of the outer surface of the container body was covered by the transparent conductive part. The remaining portion of the transparent conductive part (approximately 40 mm) was extended upwards. The extended portion of the transparent conductive part was not in contact with the container body, and the two electrodes were exposed. Water was poured into the container body to a level equivalent to 90% of its capacity. The water temperature was set to room temperature (23°C).

For each sample container, alligator clips were attached to the transparent conductive part, and a voltage of 10V was applied using a DC regulated power supply ("TEXIO PW36-1.5ADP," manufactured by TEXIO Technology Corporation). The temperature distribution on the surface of each sample container was then measured using a thermographic camera ("FLIR Ex E4," manufactured by FLIR Systems).

Evaluation 8 involved observing the surface temperature of the sample container and visually determining the temperature (color) distribution. A "△" rating indicated that less than 50% of the sample container was heated, a "〇" rating indicated that almost the entire sample container was heated, and a "◎" rating indicated that the entire sample container was evenly and uniformly heated.
Figure 14 shows the test results for each sample container in Examples 7 to 12 for the evaluation items described above. Figure 14 shows the test results for Example No. 3.
As shown in Figure 14, it was found that by making the length ratio of the divided portion 50% or more, almost the entire container can be heated. It is also presumed that the test results for Example No. 3 would be similar if the transparent conductive portion were the first configuration (second embodiment) without divided portions.

The embodiments of the present invention have been described above, but the present invention is not limited to the embodiments described above. Various modifications and changes are possible, as shown in the modified forms described later, and these are also included within the technical scope of the present invention. The effects described in the embodiments above are merely a list of the most preferred effects resulting from the present invention and are not limited to those described in the embodiments. The embodiments described above and the modified forms described later can be used in combination as appropriate, but a detailed explanation is omitted. Hereinafter, the first and second embodiments will be collectively referred to as "embodiments."

(Transformed form)
In the heat retention system 1(2) of the embodiment, the power supply device 20 may be provided with a temperature adjustment mechanism, or a timer mechanism for setting the start and stop of heat retention. Alternatively, a switch mechanism for switching the heat retention on and off may be provided on the heat retention container 10.
In the heat-insulating container 10 (110) of the embodiment, a heat insulating material may be provided on the outer circumference of the transparent conductive part 112 (112).

In the warming system 1(2) of the embodiment, after heating or boiling the contents in the warming container 110 to a predetermined temperature, the supply of electrodes from the power supply unit 22 to the power supply mat 21 may be temporarily stopped, and the system may be configured to switch to warming mode when the temperature of the contents drops to a desired level. That is, a mode switching mechanism may be provided to switch from normal heating mode to warming mode, or from boiling mode to warming mode. By providing such a mode switching mechanism, it becomes possible to use the system in a way that, when preparing infant formula, the milk is boiled once, and then switched to warming mode when it has cooled to body temperature.

In the heat-retaining container 10 (110) of the embodiment, the power receiving section 13 may be made of a metal nanowire, for example, a silver nanowire.
In the embodiment, water, beverages, lotions, etc. were given as examples of contents to be held in the insulated container 10 (110), but the contents may be, for example, food, medicine, oils, detergents, paints, fuels, etc. Furthermore, the contents to be held in the insulated container 10 (110) may be liquid or solid.

In the second configuration of the second embodiment (see Figure 10), the number of divided portions 113 formed in the transparent conductive portion 112 is not limited to one, but may be two or more.
Figure 15 is a plan view showing the configuration of a transparent conductive part 112 with three divided parts 113. In the configuration shown in Figure 15, components equivalent to those in the second embodiment are denoted by the same reference numerals, and redundant explanations are omitted as appropriate.

The transparent conductive portion 112 shown in Figure 15 has three divided sections 113a to 113c. Divided sections 113a and 113b are formed on the upper side Y1 of the transparent conductive portion 112, and divided section 113c is formed on the lower side Y2. The divided sections 113a to 113c are formed alternately on the upper side Y1 and the lower side Y2 along the width direction X of the transparent conductive portion 112. The length L5 in the height direction Y of the divided sections 113a to 113b may be within the range described in the second embodiment, and their lengths may be the same or different.

As shown in Figure 15, a first electrode 118 and a second electrode 119 are formed on the upper Y1 of the transparent conductive portion 112, insulated by the divided portions 113a and 113b. A common electrode 120a is formed between the divided portions 113a and 113b. Within the region of the conductive material formed along the upper Y1 of the transparent conductive portion 112, the common electrode 120a is formed in the region between the divided portions 113a and 113b, the first electrode 118 is formed in the region to the left of the divided portion 113a, and the second electrode 119 is formed in the region to the right of the divided portion 113b.

On the other hand, common electrodes 120b and 120c are formed on the lower side Y2 of the transparent conductive portion 112, separated by the dividing portion 113c. Within the region of the conductive material formed along the lower side Y2 of the transparent conductive portion 112, the common electrode 120b is formed in the region to the left of the dividing portion 113c, and the common electrode 120c is formed in the region to the right of the dividing portion 113c.

As shown in Figure 15, the transparent conductive portion 112 is divided into a first conductive portion 117A, a second conductive portion 117B, a third conductive portion 117C, and a fourth conductive portion 117D by the formation of three divided portions 113a to 113c in the transparent conductive portion 112. The first conductive portion 117A and the second conductive portion 117B are not divided below the divided portion 113a Y2 and are electrically connected by a conductive region 117E. The second conductive portion 117B and the third conductive portion 117C are not divided above the divided portion 113c Y1 and are electrically connected by a conductive region 117F. The third conductive portion 117C and the fourth conductive portion 117D are not divided below the divided portion 113b Y2 and are electrically connected by a conductive region 117G.

In the transparent conductive portion 112 shown in Figure 15, when a voltage is applied between the first electrode 118 and the second electrode 119, and a current is flowed, for example, from the first electrode 118 to the second electrode 119, the current flows downward Y2 from the first electrode 118 through the first conductive portion 117A, through the conductive region 117E and the common electrode 120b, and then upward Y1 through the second conductive portion 117B. Subsequently, the current flows downward Y2 through the third conductive portion 117C through the conductive region 117F and the common electrode 120a, through the conductive region 117G and the common electrode 120c, and then upward Y1 through the fourth conductive portion 117D, reaching the second electrode 119. Therefore, even in this embodiment of the transparent conductive portion 112 with divided portions 113a to 113c, the contents held in the heat-retaining container 10 can be kept warm, similar to the second embodiment described above.

1,2 Insulation system 10,110 Insulation container 11 Container body 12,112 Transparent conductive part 17,117 Transparent conductive sheet 18,118 First electrode 19,119 Second electrode 20 Power supply device 33 Conductive layer 35 Conductive fiber 36 Light-transmitting resin 113a-113c Divided parts 114,120a-120c Common electrode 117A First conductive part 117B Second conductive part 117C Third conductive part 117D Fourth conductive part 117E-117H Conductive region

Claims (11)

A container body that holds the contents,
A transparent conductive part is provided on at least the outer peripheral surface of the container body, which generates heat when power is supplied,
The transparent conductive part and the power receiving part are electrically connected,
Equipped with ,
The surface resistivity of the transparent conductive part is,
The temperature measured when voltages of 15V and 5V are applied to the transparent conductive part for 15 seconds each is,
The temperature is set to satisfy the relationship 20°C < (temperature when 15V is applied - temperature when 5V is applied) < 70°C.
Thermal container. In the heat-insulating container according to claim 1 ,
The surface resistivity of the transparent conductive part is,
The temperature measured when voltages of 15V and 5V are applied to the transparent conductive part for 15 seconds each is,
The temperature is set to satisfy the relationship 20°C < (temperature when 15V is applied - temperature when 5V is applied) < 45°C.
Thermal container. In the heat-insulating container according to claim 1 ,
The surface resistivity of the transparent conductive part is,
The temperature measured when voltages of 15V and 5V are applied to the transparent conductive part for 15 seconds each is,
The temperature is set to satisfy the relationship 45°C < (temperature when 15V is applied - temperature when 5V is applied) < 70°C.
Thermal container. In a heat-insulating container according to any one of claims 1 to 3 ,
The surface resistivity of the transparent conductive part is 5 to 75 Ω/□.
Thermal container. In the heat-insulating container according to claim 1,
The transparent conductive part includes a resin part and metal nanowires disposed in the resin part.
Thermal container. In the insulated container according to claim 5 ,
The aforementioned metal nanowire is a silver nanowire.
Thermal container. In the heat-insulating container according to claim 1,
The container body is cylindrical with a bottom,
The transparent conductive part comprises a transparent conductive sheet, a first electrode, and a second electrode.
The first electrode is provided on one side edge in the width direction of the container body of the transparent conductive sheet,
The second electrode is provided on the other side edge in the width direction of the container body of the transparent conductive sheet.
Thermal container. In the heat-insulating container according to claim 1,
The container body is cylindrical with a bottom,
The transparent conductive part comprises a transparent conductive sheet, a first electrode, and a second electrode.
The transparent conductive sheet is divided into a first conductive portion and a second conductive portion by a dividing portion formed from one side edge to the other side edge in the height direction of the container body.
The first conductive part and the second conductive part are electrically connected at the other side edge in the height direction of the container body.
The first electrode is provided on one side edge in the height direction of the container body of the first conductive part.
The second electrode is provided on one side edge in the height direction of the container body of the second conductive part.
Thermal container. In the heat-insulating container according to claim 8 ,
The first conductive portion and the second conductive portion of the transparent conductive sheet are electrically connected by a common electrode provided on the other side in the height direction of the container body.
Thermal container. In the heat-insulating container according to claim 9 ,
The division portion is formed from one side edge in the height direction of the transparent conductive sheet to a range of 30 to 100% of the length of the transparent conductive sheet in the height direction.
Thermal container. The insulated container according to claim 1,
A power supply device that supplies power to the transparent conductive part of the aforementioned heat-insulating container by wireless power transfer,
A heating system equipped with this feature.