TW202137811A - Heat-generating film and method for manufacturing heat-generating film - Google Patents

Abstract

Provided is a heat-generating film that has less visible electrically conductive portions, has high transparency (transmittance), and is capable of generating a sufficient amount of heat when energized. The heat-generating film is provided in a surface thereof with a plurality of first grooves extending in a first direction, a transparent film having a plurality of second grooves extending in a second direction across the first direction, and electrically conductive portions present in the first and second grooves. The electrically conductive portions have a line width of 0.2 to 10 [mu]m and a height of 0.5 to 10 [mu]m. The interval between the electrically conductive portions present in two of the first grooves adjacent to each other is 20 to 1000 [mu]m. The number of intersecting points of the electrically conductive portions present in the first grooves and the electrically conductive portions present in the second grooves is 20 to 2500 per cm2. The area ratio of the electrically conductive portions is 0.1 to 10%.

Description

Heating film and manufacturing method of heating film

The present invention relates to a heating film and a manufacturing method of the heating film.

In vehicles such as automobiles, in order to maintain a good view of the driver while driving, a mechanism is sometimes installed on the windows or mirrors to prevent the adhesion of fog, frost, water droplets, etc. For example, the rear window of a car is provided with a demister composed of a heating wire printed on the glass of the rear window. The mist and frost on the rear window can be removed by heating the glass with the heating wire of the demister (for example, Patent Document 1). In addition, for example, a heater for heating the side mirrors to prevent the adhesion of water droplets is provided on the back (rear side) of the side mirrors of automobiles (for example, Patent Document 2). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2006-117026 [Patent Document 2] Japanese Patent Laid-Open No. 2005-138672

[The problem to be solved by the invention]

However, the electric heating wire of the defogger can be visually recognized, resulting in the so-called "internal visibility and phenomenon". Therefore, the vision of the vehicle driver is hindered, and the design of the vehicle is also reduced. Since the heater installed in the side mirror is installed on the back of the mirror, it will not affect the vision of the vehicle driver or the design of the vehicle, but the heating efficiency of the mirror becomes low. In order to improve the heating efficiency, installing the heater on the front surface of the side mirror will damage the vision of the vehicle driver and reduce the design of the vehicle, which is not ideal.

The present invention solves the above-mentioned problems and provides a heat-generating film that not only maintains the vision of the vehicle driver and the design of the vehicle, but also efficiently heats the windows, mirrors, etc. of the vehicle. [Technical means to solve the problem]

According to a first aspect, there is provided a heat generating film comprising: a transparent film having a plurality of first grooves extending in a first direction and a plurality of second grooves extending in a second direction intersecting the first direction on the surface Grooves; and conductive parts, which are present in the first and second grooves; and the line width of the conductive part is 0.2-10 μm, the height of the conductive part is 0.5-10 μm, and it exists in two adjacent first The interval between the conductive parts in the groove is 20-1000 μm, and the number of intersections between the conductive parts in the first groove and the conductive parts in the second groove is 20-2500/cm ² , The area ratio of the conductive portion is 0.1 to 10%.

The light transmittance of the heating film at a wavelength of 550 nm can be 60-98%. The sheet resistance value of the heating film can be 0.003～70 Ω/sq. The interval between the above-mentioned conductive parts existing in two adjacent second grooves in the first direction may be 1000-15000 μm. The second direction may be orthogonal to the first direction.

It can be equipped with a plurality of first multi-line parts composed of conductive parts existing in a plurality of first grooves, and two adjacent first multi-line parts are arranged at a first interval of 20-1000 μm to form the above-mentioned first multi-line part The plurality of conductive parts are arranged at a fourth interval smaller than the first interval. The fourth interval can be 0.2-20 μm.

It can be provided with a plurality of second multi-line parts composed of conductive parts existing in a plurality of second grooves, and two adjacent second multi-line parts are arranged at a second interval in the first direction to form the above-mentioned second multi-line part The plurality of conductive parts are arranged at a fifth interval smaller than the second interval in the first direction. The fifth interval may be 0.5-20 μm.

According to a second aspect, there is provided a method of manufacturing a heat-generating film, which is a method of manufacturing the heat-generating film of the first aspect, which includes the steps of: preparing the above-mentioned transparent film having a first groove and a second groove on the surface; And the second groove is filled with a conductive material to form the above-mentioned conductive portion.

The step of preparing the transparent film may include the step of forming a first groove and a second groove on the transparent film by imprinting using a mold having a concave-convex pattern corresponding to the conductive portion. The transparent film has a transparent supporting substrate and a transparent resin layer formed on the transparent supporting substrate. The step of preparing the transparent film may include the following steps: preparing the mold having a concave-convex pattern corresponding to the conductive portion; A photocurable resin is applied to the surface on which the uneven pattern is formed to form a coating layer; the transparent supporting substrate is arranged on the coating layer; ultraviolet light is irradiated from the transparent supporting substrate side to harden the coating layer, And forming the above-mentioned transparent resin layer; and peeling the above-mentioned mold from the above-mentioned transparent resin layer. The above-mentioned conductive part can be formed by electroless plating. [Effects of Invention]

The heating film of the present invention can suppress the internal visibility and phenomenon of the conductive part, has high transparency (transmittance), and can obtain sufficient heat generation when energized. Therefore, it can be used as a heat generating film that not only maintains the vision of the vehicle driver and the design of the vehicle, but also efficiently heats the windows and mirrors of the vehicle. In addition, the heating film of the present invention is not easily affected by the disconnection of the conductive part, and has high durability and reliability.

Hereinafter, embodiments of the heat generating film and the manufacturing method thereof of the present invention will be described with reference to the drawings.

[Heating film] As shown in FIG. 1(a), the heating film 10 of this embodiment includes: a transparent film 11 including a transparent support base 33 and a transparent resin layer 12 formed thereon; and a conductive portion 13 formed on the transparent film 11 on. The transparent resin layer 12 has a recessed portion (groove) 11c having a rectangular cross-section. As shown in FIG. 2, the concave portion 11c includes a first groove 11A extending in a first direction on the surface 11s of the transparent film 11 and a second groove 11B extending in a second direction intersecting the first direction. The recesses (grooves) 11c including the first groove 11A and the second groove 11B are lattice grooves that form a lattice pattern (pattern A) when the heating film 10 is viewed in plan. In the pattern A, the first direction and the second direction are orthogonal. The conductive portion 13 is formed by filling the recess 11c of the transparent film 11 with a conductive material. That is, the conductive part 13 exists in the recessed part 11c. The conductive portion 13 includes a first conductive portion 13A filled in the first groove 11A, and a second conductive portion 13B filled in the second groove 11B. As shown in FIG. 2, the first conductive portion 13A and the second conductive portion 13B have a grid shape, and a grid pattern (pattern A) is formed on the surface 11 a of the transparent film 11. In addition, when there is no need to distinguish between the first groove 11A and the second groove 11B, they are collectively described as the concave portion (groove, lattice groove) 11c. Similarly, when there is no need to distinguish between the first conductive portion 13A and the second conductive portion 13B, they are collectively described as the conductive portion 13.

＜Transparent film＞ As described above, the transparent film 11 has a transparent supporting base 33 and a transparent resin layer 12 laminated thereon.

As the transparent resin layer 12, resins such as light curing, thermal curing, moisture curing, and chemical curing (two-component mixing) can be used. Specifically, for example, epoxy, acrylic, methacrylic, vinyl ether, oxetane, urethane, melamine, urea, polyester, polyolefin Various resins such as monomers, oligomers, and polymers such as phenolic, phenolic, cross-linked liquid crystal, fluorine, silicone, and polyamide resins. The thickness of the transparent resin layer 12 may be in the range of 0.5 to 500 μm, 1 to 400 μm, 5 to 200 μm, or 2 to 20 μm. If the thickness is less than the above lower limit, the depth of the recess 11c formed in the transparent resin layer 12 is likely to become insufficient. If the thickness exceeds the above upper limit, there is a concern that the influence of the volume change of the resin generated during curing will increase.

As the transparent support substrate 33, a known film substrate that transmits visible light can be used. For example, a substrate containing transparent inorganic materials such as glass can be used; including polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyarylate, etc.), ( Meth) acrylic resin (polymethyl methacrylate, etc.), polycarbonate, polyvinyl chloride, styrene resin (ABS resin, etc.), cellulose resin (triacetyl cellulose, etc.), polyamide Amine resin (polyimide resin, polyimide amide resin, etc.), cyclic olefin polymer and other resin base materials. From the viewpoint of flexibility, the transparent support base 33 may be a resin film. From the viewpoint of optical characteristics, the thickness of the transparent support substrate 33 is preferably 1 to 500 μm, 10 to 300 μm, or 20 to 150 μm. When it is thinner than 1 μm, the function as a supporting substrate may be impaired, and when it is thicker than 500 μm, the light transmittance may be insufficient.

＜Conductive part＞ The conductive portion 13 generates heat by energization. Therefore, the conductive portion 13 is the heat generating portion of the heat generating film 10. As shown in FIG. 1(b), the conductive part 13 is formed by filling the recessed part (groove) 11c of the transparent film 11, and does not overflow to the outside of the in-plane direction of the film of the recessed part 11c. In this embodiment, there is no step difference between the upper surface 13s (the portion exposed from the groove) of the conductive portion 13 and the surface 11s of the transparent film 11, and the two are located in the same plane. That is, the depth D of the recessed portion 11c is substantially the same as the height H of the conductive portion 13. In addition, the surface 11s of the transparent film 11 means the surface part excluding the concave portion 11c of the transparent film 11.

The line width W of the conductive portion 13 is 0.2 to 10 μm, preferably 0.5 to 10 μm, 0.7 to 8 μm, 0.9 to 6 μm, or 1 to 5 μm. If the line width W of the conductive portion 13 exceeds the upper limit of the above-mentioned range, the conductive portion 13 can be visualized, and internal visibility and phenomenon may occur, and the transparency (transmittance) of the heating film 10 may decrease. In addition, if the line width W of the conductive portion 13 does not reach the lower limit of the aforementioned range, the conductivity may become insufficient and the amount of heat generation may be insufficient. In addition, the risk of disconnection of the conductive portion 13 increases, and the durability and reliability of the heating film 10 decrease. In addition, the line width W of the conductive portion 13 is the maximum value of the width of the conductive portion 13 in the cross section perpendicular to the direction in which the conductive portion 13 extends. In this embodiment, the first conductive portion 13A and the second conductive portion 13B have the same line width W. However, this embodiment is not limited to this, and the first conductive portion 13A and the second conductive portion 13B may have different line widths W, respectively.

The height H of the conductive portion 13 is 0.5 to 10 μm, preferably 0.7 to 7 μm, 1 to 5 μm, or 2 to 4 μm. If the height H of the conductive portion 13 exceeds the upper limit of the above range, it is difficult to form a grid pattern. In addition, if the height H of the conductive portion 13 does not reach the lower limit of the above-mentioned range, the conductivity may become insufficient and the amount of heat generation may be insufficient. The durability and reliability of the heating film 10 are reduced. Furthermore, the height H of the conductive portion 13 refers to the maximum value of the distance from the bottom of the recess 11c to the surface 13s of the conductive portion 13 (the thickness of the conductive portion 13). In this embodiment, the first conductive portion 13A and the second conductive portion 13B have the same height H. However, this embodiment is not limited to this, and the first conductive portion 13A and the second conductive portion 13B may have different heights H, respectively.

As shown in FIG. 1(b), the height H of the conductive portion 13 may preferably be more than 0.1 times, 0.1 to 5 times, or 0.5 to 2 times the line width W of the conductive portion 13. That is, the aspect ratio of the cross-sectional shape in the plane perpendicular to the extending direction of the conductive portion 13 may preferably be in the range of 1:10 to 5:1 or 1:2 to 2:1. Since the height H of the conductive portion 13 of this embodiment is more than one time of the line width W, the conductive portion 13 can have sufficient conductivity and heat generation. Thereby, the heating film 10 can have both good appearance and high conductivity without internal visibility and phenomenon. In addition, when the height H of the conductive portion 13 is greater than 5 times the line width W, the visibility of the heating film 10 may decrease when the heating film 10 is viewed obliquely.

The depth D of the concave portion 11c and the height H of the conductive portion 13 may not be equal. For example, as shown in FIG. 3(a), the height H of the conductive portion 13 may be higher than the depth D of the concave portion 11c. That is, the conductive portion 13 may have a raised portion 13x (a portion higher than the surface 11s of the transparent film 11). Even so, the raised portion 13x is not exposed to the outer side of the recessed portion 11c in the in-plane direction of the substrate. Thereby, the cross-sectional area of the conductive portion 13 can be increased, and as a result, the resistance value of the conductive portion 13 can be reduced without increasing the area ratio (coverage rate) of the conductive portion 13 in the grid pattern. The height of the raised portion 13x (the height from the surface 11s) is preferably set to 0.5 μm or less. If it exceeds 0.5 μm, the wear resistance of the conductive part decreases. From the viewpoint of wear resistance, the ratio (H/D) of the height H of the conductive portion 13 to the depth D of the recess 11c is preferably 1.0<H/D≦1.2, 1.0<H/D≦1.15 or 1.0 <H/D≦1.10 (where the height of the protruding portion 13x is 0.5 μm or less).

Alternatively, as shown in FIG. 3(b), the conductive portion 13 may have a lower depth than the concave portion 11c, and the conductive portion 13 may be partially filled in the concave portion 11c. As a result, the conductive portion 13 is completely contained in the recess, so the surface of the transparent film 11 has excellent abrasion resistance, and the conductive portion 13 is not easily deteriorated. From the viewpoint of ensuring conductivity, the ratio (H/D) of the height H of the conductive portion 13 to the depth D of the recess 11c is preferably 0.1<H/D, 0.3≦H/D, or 0.5≦H/D.

In this embodiment, as shown in FIG. 2, a plurality of conductive portions 13 (the first conductive portion 13A and the second conductive portion 13B) having the same line width W and the same height H regularly intersect in a grid pattern, and are transparent A lattice pattern (lattice pattern A) is formed on the surface 11s of the film 11. Since the first conductive portion 13A and the second conductive portion 13B are orthogonal to each other, the conductive portions 13 are evenly dispersed in a plan view, thereby suppressing internal visibility and phenomena, and improving transparency. In addition, the pattern A has a plurality of intersections R at which the first conductive portion 13A and the second conductive portion 13B cross (orthogonal). The details will be described below. However, since the pattern A has an intersection point R, the heating film 10 of this embodiment is not easily affected by the disconnection of the conductive portion 13, and has high durability and reliability.

The interval between the conductive parts filled in the two adjacent first grooves 11A, that is, the first interval P1 between the two adjacent first conductive parts 13A is 20-1000 μm, preferably 50-800 μm, 80～600 μm or 90～500 μm. If the first interval P1 does not reach the lower limit of the above range, the transparency (transmittance) of the heat generating film 10 may decrease. In addition, if the first interval P1 exceeds the upper limit of the above-mentioned range, the heat generation amount of the heat generating film 10 may be insufficient. In addition, since the number of intersections R is reduced, the heat generating film 10 is easily affected by the disconnection of the conductive portion 13, and there is a risk that durability and reliability may be reduced. Furthermore, the first interval P1 is the distance (interval) between two adjacent first conductive portions 13A in a direction perpendicular to the first direction. In the pattern A in which the first direction and the second direction are orthogonal, the first interval P1 is the distance (interval) in the second direction. In addition, the first interval P1 is the distance between the opposing edges (ends) of two adjacent first conductive portions 13A in a direction perpendicular to the first direction.

The gap between the conductive portions filled in the first direction to the two adjacent second grooves 11B, that is, the second gap P2 between the two adjacent second conductive portions 13B in the first direction is not particularly limited . From the viewpoint of allowing the heat generating film 10 to have both transparency and heat generation, for example, it may be 20 to 20000 μm, 50 to 15000 μm, 80 to 6000 μm, or 90 to 3000 μm. If the second interval P2 is in the above range, high transparency (transmittance) can be achieved. Moreover, in the pattern A shown in FIG. 2, the second interval P2 is larger (wider) than the first interval P1, but the present embodiment is not limited to this. The first interval P1 and the second interval P2 may be the same or different. However, from the viewpoint of suppressing visibility and phenomena inside the conductive portion 13 and improving transparency (transmittance), the second interval P2 is preferably larger (wider) than the first interval P1. Furthermore, the second interval P2 is the distance between the opposing edges (ends) of two adjacent second conductive portions 13B in the first direction.

The first interval P1 and the second interval P2 together with the line width W of the conductive portion 13 may affect the internal visibility and phenomenon of the conductive portion 13. Although it depends on the size of the line width W of the conductive portion 13, if the first interval P1 and the second interval P2 become smaller (narrow), the internal visibility and phenomenon of the conductive portion 13 may be further suppressed. It is presumed that the reason is that the human eyes cannot recognize the size of the first interval P1 and the second interval P2, and the grid pattern of the conductive portion 13 becomes less conspicuous. For example, when the line width W of the conductive portion 13 is 2 μm or less, the first interval P1 is less than 300 μm and the second interval P2 is less than 5000 μm, the internal visibility and phenomenon are further suppressed, which is preferable. Furthermore, as described above, if the second interval P2 is too narrow, the transparency may decrease. Therefore, the second interval P2 is preferably 1000 or more, for example. Therefore, in order to suppress internal visibility and phenomena and obtain high transparency, for example, when the line width W of the conductive portion 13 is 2 μm or less, it is preferable that the first interval P1 is less than 300 μm and the second interval P2 is 1000～ Below 5000 μm.

The number of intersections R in the grid-shaped conductive portion 13, that is, the number of intersections R between the first conductive portion 13A existing in the first groove 11A and the second conductive portion 13B existing in the second groove 11B is 20 ~2500 pcs/cm ² , preferably 30-2000 pcs/cm ² or 50-1500 pcs/cm ² . In the present embodiment, when the conductive portion 13 as the heating portion is disconnected, the periphery of the disconnected portion cannot be energized and cannot generate heat, and a part of the surface 11s of the heating film 10 cannot function as a heating film. In the surface 11s of the heating film 10, the area that cannot contribute to heat generation due to the disconnection of the conductive portion 13 at one site is defined as the "disconnection affected area". In the grid pattern, the greater the number of intersections R, the smaller the area affected by the disconnection. That is, the greater the number of intersections R, the less susceptible the heating film 10 is to the disconnection of the conductive portion 13, and the higher the durability and reliability of the heating film 10 is. If the number of intersections R in the lattice pattern does not reach the lower limit of the above range, the heating film 10 cannot obtain sufficient durability and reliability. Conversely, if the number of intersections R in the grid pattern exceeds the upper limit of the above-mentioned range, the transparency (transmittance) of the heating film 10 may decrease.

In addition, the area ratio of the conductive portion 13 is 0.1 to 10%, preferably 0.2 to 3% or 0.3 to 1%. If the area ratio of the conductive portion 13 does not reach the lower limit of the above range, there is a risk of insufficient heat generation. If the area ratio of the conductive portion 13 exceeds the upper limit of the above-mentioned range, the transparency (transmittance) of the heating film 10 may decrease. Furthermore, the area ratio of the conductive portion 13 refers to the coverage of the conductive portion 13 in the area where the grid-shaped conductive portion 13 is formed on the surface of the heating film 10 (the area where the grid pattern A is formed) when the heating film 10 is viewed from above.

Examples of the material of the conductive portion 13 include metals such as nickel, copper, zinc, chromium, palladium, silver, tin, lead, gold, aluminum, and alloys or compounds of these metals. From the viewpoint of conductivity, metals such as nickel, copper, silver, gold, and alloys or compounds of these metals are preferred, and from the viewpoint of flexibility, metals such as silver, copper, nickel, or the like are preferred. alloy.

The light transmittance of the heating film 10 of this embodiment at a wavelength of 550 nm may preferably be 60-98%, 80-95%, or 85-92%. If the transmittance is within the above range, the heat generating film 10 has sufficient transparency.

The sheet resistance value of the heating film 10 of this embodiment may preferably be 0.003 to 70 Ω/sq., 0.05 to 30 Ω/sq., or 0.1 to 20 Ω/sq. If the sheet resistance value is in this range, the heat generating film 10 can obtain sufficient heat generation when it is energized.

The heating rate of the heat generating film 10 of the present embodiment may preferably be 0.02 to 0.5° C./sec., 0.03 to 0.4° C./sec., or 0.04 to 0.3° C./sec. If the temperature increase rate is within this range, the heat generating film can exhibit sufficient heat generation characteristics when energized. In addition, the rate of temperature increase can be measured using, for example, the measurement method and measurement conditions described in the following examples.

The heating film 10 may be provided with a lead wire connected to the end of the conductive portion 13 in order to generate heat by energizing the conductive portion 13. The lead wires can be set to the same height as the upper surface 13s of the conductive portion 13. In particular, there is no step difference between the upper surface 13s of the conductive portion 13 and the surface 11s of the transparent film 11a, and both can be located in the same plane. As the material for the lead-out wiring, the same materials as those exemplified as the material of the conductive portion 13 can be used.

As described above, the line width W and height H of the first conductive portion 13A and the second conductive portion 13B of the heating film 10 of the present embodiment, the first interval P1 in the grid pattern, the number of intersections, and the area of the conductive portion The ratio is within a specific range. Thereby, the heat generating film 10 of the present embodiment can suppress the internal visibility and phenomenon of the conductive part, has high transparency (transmittance), and can obtain sufficient heat generation when energized. Furthermore, the heating film of this embodiment is not easily affected by the disconnection of the conductive part, and has high durability and reliability. Therefore, the heat-generating film 10 of this embodiment can be used as a heat-generating film capable of efficiently heating windows, mirrors, etc. of a vehicle without degrading the visual field of the vehicle driver and the design of the vehicle.

[Manufacturing method of heating film] As shown in the flowchart of FIG. 4, the manufacturing method of the heating film 10 includes the following steps: preparing a transparent film 11 with lattice grooves 11c (first groove 11A and second groove 11B) formed on the surface 11s (Step S1 in FIG. 4) And the grid groove 11c is filled with a conductive material to form the conductive portion 13 (the first conductive portion 13A and the second conductive portion 13B) (Step S2 in FIG. 4). The heating film 10 can be manufactured, for example, by using a mold having a concave-convex pattern corresponding to the conductive portion 13 to form the concave-convex transparent film 11 by imprinting, and then filling the concave portion with the conductive member by electroless plating . Hereinafter, a specific example of the manufacturing method of the heating film 10 will be described with reference to FIGS. 5 and 6.

＜Preparation steps of the mould＞ As shown in FIG. 5(a), a mold 20 with a concave-convex pattern having a rectangular cross-sectional shape formed with convex portions 20a formed at predetermined intervals on the surface is prepared. The concave-convex pattern of the mold is a grid pattern in which a plurality of straight portions intersect at a specific interval when viewed from above (refer to pattern A in FIG. 2). The height and width of the convex portion 20a and the interval between the convex portions 20a are set to be the same as the design dimensions of the conductive portion 13 described above. The mold 20 can be produced by, for example, a photolithography method in which a photoresist coated on a silicon substrate is sensitized and etched using a photomask with a specific pattern. It is preferable to coat the surface of the mold 20 with a release agent used in the following steps.

＜Preparation steps of transparent film by imprinting＞ Next, a photocurable resin such as an ultraviolet curable resin is coated on the surface of the mold 20 where the protrusions 20a are formed to form the coating layer 22. Next, a transparent support substrate 33 containing synthetic resin, such as a PET (Polyethylene) film, is arranged on the coating layer 22 to form a laminate as shown in FIG. 5(b). Next, the layered body is irradiated with ultraviolet light from the transparent support base 33 side. Thereby, the photocurable resin constituting the coating layer 22 is cured, and the transparent resin layer 12 is formed. Next, as shown in FIG. 5(c), the mold 20 is peeled from the transparent resin layer 12 of the laminate to obtain a grid-like depression (lattice groove) 11c formed on the surface corresponding to the pattern of the mold's convex portion 20a The transparent film 11 of the transparent resin layer 12.

＜Formation of conductive part by electroless plating＞ The conductive portion 13 is formed in the concave portion 11c of the transparent resin layer 12 of the transparent film 11 obtained in the above manner by electroless plating in the following manner.

(A) Formation of plating catalyst base layer (silane coupling treatment) When performing electroless plating, in order to ensure the firm adhesion of the plating film, it is preferable to perform a silane coupling treatment on the part where the plating film is applied. As the silane coupling agent used in this treatment, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, or N-2 (aminoethyl) 3-amino group can be used. Aminosilane compounds such as propylmethyldimethoxysilane and 3-(N-phenyl)aminopropyltrimethoxysilane or silane compounds with other reactive functional groups. By coating the silane coupling agent solution on the surface 11s of the transparent film 11, as shown in FIG. 6(a), a base layer 28 is formed on the surface of the transparent resin layer 12 including the concave portion 11c. In order to improve the adhesion of the base layer 28 to the surface of the transparent resin layer 12, the transparent film 11 may be heated after the solution of the base layer forming material is applied. Furthermore, before applying the solution of the base layer forming material, UV (Ultraviolet) light may be irradiated to the surface of the transparent resin layer 12 to modify the surface of the transparent resin layer 12.

Next, a treatment is performed such that the base layer 28 exists only on the inner surface of the recess 11c. This treatment includes, for example, a step of irradiating UV light only to the base layer 28 on the surface of the transparent resin layer 12 except for the opening of the recess 11c. If necessary, a light-shielding mask can also be used. As a result, as shown in FIG. 6(b), a transparent film 11 in which the base layer 28 exists only on the inner surface of the recess 11c can be obtained.

(B) Loading of plating catalyst Next, the transparent film 11 in which the base layer 28 exists only on the inner surface of the recess 11c obtained in the above-mentioned manner is immersed in a known plating catalyst solution. Thereby, a transparent film (precursor of the transparent film for plating) in which metal ions (for example, palladium ions) as a plating catalyst are carried only inside the recess 11c is obtained. As the plating catalyst solution, a palladium (II) chloride solution or a tetrachlorogold (III) acid solution can be used. Furthermore, by performing a reduction treatment on the transparent film, a transparent film (transparent film for plating) in which a plating catalyst such as palladium is adhered to only the inner surface of the recess 11c can be obtained.

(C) Electroless plating Finally, the transparent film 11 (transparent film for plating) is immersed in an electroless plating solution to perform electroless plating. By electroless plating, a conductive material is formed only inside the recess 11c. In this way, the heat generating film 10 in which the conductive portion 13 is formed inside the recess 11c as shown in FIG. 6(c) can be obtained.

＜Examples of changes＞ In the above-mentioned embodiment, the pattern A shown in FIG. 2 is used as the grid pattern (lattice pattern) formed by the conductive portion 13, but this embodiment is not limited to this. If it is a pattern in which a plurality of straight portions (conductive portions 13) intersect at specific intervals in a plan view, it can be used as a lattice pattern. For example, in the pattern A, the second interval P2 is longer than the first interval P1, so the planar shape of each grid is rectangular (rectangular), but the first interval P1 and the second interval P2 may be equal. In this case, the planar shape of each grid becomes a square.

In the pattern A shown in FIG. 2, the first conductive portions 13A are arranged at the first intervals P1 at equal intervals, but the grid pattern of the present embodiment is not limited to this. The grid pattern of this embodiment may also be a pattern D1 as shown in FIG. 7(a), and a plurality of first conductive portions 13A may constitute the first polyline portion 13AW. The two adjacent first polyline portions 13AW are arranged at a first interval P1. In the first multiple wire portion 13AW, a plurality of first conductive portions 13A are arranged at a fourth interval P4 narrower than the first interval P1. By forming the first polyline portion 13AW of the first conductive portion 13A, the number of intersections R increases, and the area affected by the disconnection becomes smaller. As a result, the heating film 10 using the pattern D1 is less susceptible to the disconnection of the conductive portion 13, and the durability and reliability become higher. The fourth interval P4 may be 0.2 to 20 μm, 0.3 to 15 μm, or 0.5 to 10 μm, for example. In the pattern D1, the first polyline portion 13AW is composed of three (three) first conductive portions 13A, but this modification is not limited to this. The number of the first conductive portions 13A constituting the first multi-wire portion 13AW can be set to, for example, 2 to 10, 2 to 5, or 2 to 3. Furthermore, the fourth interval P4 is the distance in the direction perpendicular to the first direction, and is the distance between the opposing edges (ends) of the two adjacent first conductive portions 13A in the first polyline portion 13AW .

The grid pattern of this embodiment may also be the same as the pattern D2 shown in FIG. 7(b), and the 2nd polyline part 13BW may be comprised by a plurality of second conductive parts 13B. Two adjacent second multi-line portions 13BW are arranged at a second interval P2 in the first direction. In the second multi-wire portion 13BW, a plurality of second conductive portions 13B are arranged at a fifth interval P5 narrower than the second interval P2 in the first direction. Since the second conductive portion 13B constitutes the second multiple-line portion 13BW, the number of intersections R increases, and the area affected by the disconnection becomes smaller. As a result, the heating film 10 using the pattern D2 is less susceptible to the disconnection of the conductive portion 13, and the durability and reliability become higher. The fifth interval P5 may be 0.5 to 20 μm, 0.7 to 15 μm, or 1.0 to 10 μm, for example. In the pattern D2, the second multi-line portion 13BW is composed of three (three) second conductive portions 13B, but this modification is not limited to this. The number of the second conductive portions 13B constituting the second multi-wire portion 13BW can be set to, for example, 2 to 10, 2 to 5, or 2 to 3. Furthermore, the fifth interval P5 is the distance in the first direction, and is the distance between the opposing edges (ends) of the two adjacent second conductive portions 13B in the second multi-wire portion 13BW.

In the heating film 10 using the pattern D1 (Figure 7(a)) or the pattern D2 (Figure 7(b)), as described above, it is not easily affected by the disconnection of the conductive portion 13, so the line width of the conductive portion 13 can also be increased W shrinks (narrows). By reducing the line width W of the conductive portion 13, the transparency (transmittance) of the heating film 10 is further improved, and the internal visibility and phenomenon of the conductive portion 13 can be further suppressed. In addition, even when the line width W of the conductive portion 13 is small, the first multiple-line portion 13AW and the second multiple-line portion 13BW are composed of a plurality of conductive portions 13 (first conductive portion 13A, second conductive portion 13B), so The heat generating film 10 can obtain sufficient heat generation. In the pattern D1 and the pattern D2, the line width W of the conductive portion 13 can be set to, for example, 0.2-10 μm, preferably 0.3-5 μm or 0.5-3 μm.

The grid pattern of this embodiment may be like the pattern E shown in FIG. 8, and the 1st direction and the 2nd direction may not be orthogonal. In this case, the lattice shape in the pattern E becomes a parallelogram. In the pattern E, by making the second direction which is the extension direction of the second conductive portion 13B approach (incline) to the first direction, it is possible to relax the application of stretching, etc. The local stress applied to the intersection of the conductive wiring during the stress.

As mentioned above, the present invention has been described through the embodiments, but the heat-generating film and the manufacturing method thereof of the present invention are not limited to the above-mentioned embodiments, and can be appropriately changed within the scope of the technical idea described in the scope of the patent application. [Example]

Hereinafter, examples of the heat generating film and its manufacturing method will be described, but the present invention is not limited to them.

[Example 1] ＜Preparation steps of transparent film＞ As the mold 20, a Si wafer (300 mm ×300 mm) (refer to Figure 5(a)). On the surface of the Si wafer, the interval between adjacent protrusions in the second direction (corresponding to the first interval P1) is set to 100 μm, and the interval between adjacent protrusions in the first direction (corresponding to the second The interval P2) is set to 5000 μm. Furthermore, the interval between the convex parts refers to the distance between the opposing edges (ends) of two adjacent convex parts in the first direction or the second direction. The mold release treatment is performed by forming a film of a fluorine-based precision mold release agent (ultra-thin film with a thickness of about 30 nm) on the surface with the convex portion.

An acrylic UV curable resin (hereinafter referred to as “UV curable resin” as appropriate) is dripped onto the surface of the mold 20 that has been subjected to the mold release treatment, and the coating layer 22 containing the UV curable resin is formed with a thickness of 13 μm. Next, a PET film (transparent support substrate 33) with a thickness of 100 μm is placed on the coating layer 22 to form a coating layer 22 (uncured transparent resin Layer 12) a laminate (see Fig. 5(b)). Next, a high-pressure mercury lamp was used to irradiate the laminate with UV light with a center wavelength of 365 nm from the PET film 33 side at 2000 mJ/cm ² to harden the UV curable resin forming the coating layer 22 to form a transparent resin layer 12 (thickness 10 μm). Next, the mold 20 is peeled from the transparent resin layer 22 of the laminate to obtain a transparent film 11 provided with a transparent resin layer 22. The transparent resin layer 22 is formed with lattice-shaped recesses ( Refer to Figure 5(c)). On the surface of the transparent film 11, the interval between adjacent recesses in the second direction (corresponding to the first interval P1) is 100 μm, and the interval between adjacent recesses in the first direction (corresponding to the second interval P2) It is 5000 μm.

＜Steps to form a plating catalyst base layer＞ The base layer raw material solution used in the silane coupling treatment was prepared in the following manner. Add 1 mL of 3-aminopropyltriethoxysilane to 200 mL of ethanol and stir for 30 minutes to prepare a 3-aminopropyltriethoxysilane solution (base layer raw material solution) (solvent: ethanol , Concentration of 3-aminopropyl triethoxysilane: 0.5% by volume).

The entire surface of the transparent resin layer 12 side surface of the transparent film 11 obtained in the above manner was irradiated with UV light at 3000 mJ/cm ^{2 to modify the surface of the transparent resin layer 12 in advance.} Next, using a bar coater, the base layer raw material solution is applied to the surface of the transparent resin layer 12 side of the transparent film 11 after surface modification so that the film thickness (wet film thickness) becomes 10 μm. On the entire surface of the transparent resin layer 12 side (the entire surface including the inner surface of the recess 11c) is formed a base layer containing 3-aminopropyltriethoxysilane (including 3 of the material as the base layer). -A layer of the reactant of aminopropyltriethoxysilane and the hydroxyl group on the transparent film) 28. Thereafter, the transparent film 11 was heated for 3 minutes in an oven heated to 70° C., so that the layer (base layer 28) containing 3-aminopropyltriethoxysilane was more fully adhered to the transparent film 11 The surface on the side of the transparent resin layer 12 and the inner surface of the recess 11c. In this way, a transparent film 11 in which a base layer 28 containing 3-aminopropyltriethoxysilane is formed on the entire surface of the transparent resin layer 12 side of the transparent film 11 and the inner surface of the concave portion 11c is obtained (refer to FIG. 6(a)).

Next, UV light is irradiated to the entire surface of the base layer 28 side surface of the transparent film 11 on which the base layer 28 is formed. Thereby, the base layer 28 existing near the surface of the transparent film 11 in the surface of the transparent film 11 and the inner surface of the recess 11c is removed. At this time, a base layer exists on the inner surface of the recess 11c except for the vicinity of the surface of the transparent film 11. That is, the transparent film 11 with the base layer 28 selectively formed only on the inner surface of the recess 11c of the transparent film 11 is obtained (refer to FIG. 6(b)).

<Steps for selecting and supporting the catalyst in the interior of the recess> As a plating catalyst solution, 1.0 mL of hydrochloric acid was added to 0.2 g of palladium (II) chloride, heated and dissolved, and then 1 L of ion exchange water was added to obtain a palladium (II) chloride solution. Secondly, by immersing the transparent film 11 with the base layer 28 formed only on the inner surface of the recess 11c in the obtained plating catalyst solution for 10 minutes at room temperature, the result is only after the formation The base layer 28 on the inner surface of the recess 11c carries a precursor of a transparent film for plating of palladium ions.

After washing the precursor of the transparent film for plating with ion-exchanged water, at room temperature, 3.2 g of dimethylamine borane was dissolved in 1 L of ion-exchanged water to obtain a reduction solution (containing a reducing agent) Soak in the treatment solution for 10 minutes. In this way, the palladium ions selectively carried in the recesses in the transparent film precursor for plating are reduced to metallic palladium, thereby obtaining a catalyst layer containing metal palladium that is selectively supported in the recesses. Transparent film for plating.

<Electroless Plating Step> An electroless plating solution (electroless copper plating solution) of the following composition is prepared. Copper sulfate pentahydrate (in ^{the form of Cu 2 +} ): 0.03 mol/L formaldehyde: 0.2 mol/L EDTA: 0.24 mol/L polyethylene glycol: 100 ppm 2,2'-bipyridine: 10 ppm sodium hydroxide ：The pH value is 12.5～13.2. The remaining amount: ion exchange water

The transparent film 11 for plating is immersed in an electroless plating solution in a plating bath, and electroless plating is performed under the conditions of temperature: 60° C. and time: 10 minutes. After that, it was washed with deionized water and dried. The copper plating film is formed only inside the recess 11c of the transparent film 11 for plating. In this way, a heat generating film 10 in which a metal conductive layer (conductive portion 13) containing copper is formed inside the concave portion 11c is obtained (see FIG. 6(c)). Furthermore, the height H of the conductive portion is set to be approximately the same as the depth D of the recessed portion of the transparent film.

[Examples 2-10] Except for changing the size of the pattern A on the Si wafer used as the mold, the heat generating film was manufactured by the same method as in Example 1. The spacing between the protrusions in the first direction and/or the second direction of the Si wafer and the cross-sectional shape (height and/or width) of the protrusions were changed to form patterns with the dimensions shown in Table 1 on the transparent film.

[Example 11] The size of the pattern A on the Si wafer used as the mold was changed, and the electroless plating solution was changed to form the conductive part by electroless nickel plating. Method of manufacturing heating film. The spacing between the protrusions in the first direction and the second direction of the Si wafer and the cross-sectional shape (height and width) of the protrusions were changed to form a pattern with the dimensions shown in Table 1 on the transparent film. In electroless plating, an electroless plating solution with the following composition (electroless nickel plating solution, pH range: 5.0-5.5) is used for electroless plating (temperature: 50°C, time: 5 minutes). Nickel sulfate hexahydrate (in ^{the form of Ni 2 +} ): 0.10 mol/L Ammonium acetate: 0.40 mol/L Sodium dihydrogen phosphate dihydrate: 0.20 mol/L The rest: ion exchange water

[Example 12] A Si wafer (300 mm×300 mm) with the pattern D1 shown in Fig. 7(a) formed on one surface by linear convex portions with a rectangular cross-sectional shape was used as a mold. In addition, by and The heating film was produced in the same way as in Example 1. Adjust the spacing between the protrusions in the first direction and/or the second direction of the Si wafer, and the cross-sectional shape (height and/or width) of the protrusions to form a pattern of the size shown in Table 2 on the transparent film. In the pattern D1, the number of the first conductive portions 13A constituting the first polyline portion 13AW is set to three (three), and the fourth interval P4 is set to 10 μm.

[Example 13] A Si wafer (300 mm×300 mm) with the pattern D2 shown in Fig. 7(b) formed on one surface by linear convex portions with a rectangular cross-sectional shape was used as a mold. In addition, by and The heating film was produced in the same way as in Example 1. Adjust the spacing between the protrusions in the first direction and/or the second direction of the Si wafer, and the cross-sectional shape (height and/or width) of the protrusions to form a pattern of the size shown in Table 2 on the transparent film. Furthermore, in the pattern D2, the number of the second conductive portions 13B constituting the second polyline portion 13BW is set to three (roots), and the fifth interval P5 is set to 10 μm.

[Examples 14 and 15] Except for changing the size of the pattern A on the Si wafer used as the mold, the heat generating film was manufactured by the same method as in Example 1. The spacing between the protrusions in the first direction and/or the second direction of the Si wafer, and the cross-sectional shape (height and/or width) of the protrusions were changed to form patterns with the dimensions shown in Table 2 on the transparent film.

[Example 16] A Si wafer (300 mm×300 mm) with the pattern D1 shown in Fig. 7(a) formed on one surface by linear convex portions with a rectangular cross-sectional shape was used as a mold. In addition, by and The heating film was produced in the same way as in Example 1. Adjust the spacing between the protrusions in the first direction and/or the second direction of the Si wafer, and the cross-sectional shape (height and/or width) of the protrusions to form a pattern of the size shown in Table 2 on the transparent film. In addition, in the pattern D1, the number of the first conductive portions 13A constituting the first polyline portion 13AW is set to 10 (10), and the fourth interval P4 is set to 2 μm.

[Comparative Examples 1 and 2] Except for changing the size of the pattern A on the Si wafer used as the mold, the heat generating film was manufactured by the same method as in Example 1. The spacing between the protrusions in the first direction and/or the second direction of the Si wafer, and the cross-sectional shape (height and/or width) of the protrusions were changed to form patterns with the dimensions shown in Table 3 on the transparent film.

[Comparative Examples 3 and 4] A Si wafer (300 mm×300 mm) with the pattern F shown in FIG. 9 formed on one surface by linear convex portions with a rectangular cross-sectional shape was used as a mold. The same method is used to manufacture the heating film. The pattern F is a so-called line/space (L/S) pattern. Lines (conductive Department).

For the heating films obtained in Examples 1 to 16 and Comparative Examples 1 to 4, the line width W and height H of the conductive parts, the first interval P1 between the first conductive parts, and the second interval P2 between the second conductive parts were measured. . Also, calculate the area ratio of the conductive parts in each pattern formed by the conductive parts, the number of intersections, and the area affected by the disconnection. The results are shown in Tables 1 to 3.

[Characteristic evaluation of heating film] ＜Electrical characteristic evaluation test＞ Using the heating films obtained in Examples 1 to 16 and Comparative Examples 1 to 4, a resistance evaluation device (trade name "Loresta-GX" manufactured by Mitsubishi Chemical Analytech) was used and the surface on which the conductive part was formed was measured by the four-point probe method. The electrical characteristics of the side are measured, and the surface resistance value is obtained. The surface resistance values obtained in this way are shown in Tables 1 to 3.

＜Transparency evaluation test＞ Regarding the heat generating films obtained in Examples 1 to 16 and Comparative Examples 1 to 4, transparency was evaluated in the following manner. A spectrophotometer (trade name "Hitachi Spectrophotometer U-4100" manufactured by Hitachi High-Technologies Corporation) was used to irradiate each heating film with light with a wavelength of 550 nm and the transmittance was measured. The measurement results are shown in Tables 1 and 2.

＜Internal visibility and phenomenon evaluation test＞ Regarding the heating film obtained in Examples 1-16 and Comparative Examples 1 to 4, the appearance of the heating film was visually inspected under a 400 lux fluorescent lamp environment, and the internal visibility and phenomenon of the wiring were evaluated according to the following criteria. The measurement results are shown in Tables 1 to 3.

＜Assessment criteria for internal visibility and phenomena＞ ◎: The wiring cannot be seen from the front and oblique observation at a distance of 30 cm ○: The wiring cannot be seen when viewed from the front at a distance of 30 cm, but the wiring can be seen when viewed obliquely △: The wiring can be clearly seen when viewed from the front at a distance of 30 cm ×: The wiring can be clearly seen when viewed from the front at a distance of 50 cm

[Table 1] Example 1 2 3 4 5 6 7 8 9 10 11 Transparent film Pattern type A A A A A A A A A A A The distance between the recesses in the second direction (equivalent to P1) (μm) 100 300 100 900 300 100 250 100 900 100 300 The first direction interval between recesses (equivalent to P2) (μm) 5000 5000 2000 2000 15000 3000 2000 8000 5000 5000 5000 Conductive part Material Cu Cu Cu Cu Cu Cu Cu Cu Cu Cu Ni The first interval P1 (μm) 99 297 98 898 298 98 249 98 899 93 297 The second interval P2 (μm) 4999 4997 1998 1998 14998 2998 1999 7998 4999 4993 4997 Line width W(μm) 1 3 2 2 2 2 1 2 1 7 3 Height H(μm) 2 3 2 2 2 2 2 2 1 2 3 Area ratio (%) 1.02 1.06 2.10 0.32 0.68 2.07 0.45 2.02 0.13 7.13 1.06 Number of intersections (pieces/cm ² ) 200 67 500 56 twenty two 333 200 125 twenty two 200 67 Affected area of disconnection (mm ² ) 0.5 1.5 0.2 1.8 4.5 0.3 0.5 0.8 4.5 0.5 1.5 evaluation result Surface resistance value (Ω/sq.) 3.1 2.0 1.5 13.9 4.6 1.5 7.7 1.5 55.7 0.4 9.2 Transmittance (550 nm) (%) 86.98 86.94 85.90 87.68 87.32 85.93 87.55 85.98 87.87 80.87 86.94 Internal Visibility and Phenomenon ◎ 〇 ◎ 〇 〇 ◎ ◎ 〇 〇 △ 〇

[Table 2] Example 12 13 14 15 16 Transparent film Pattern type D1 D2 A A D1 The distance between the recesses in the second direction (equivalent to P1) (μm) 300 300 100 100 200 The first direction interval between recesses (equivalent to P2) (μm) 5000 5000 600 1000 5000 Conductive part Material Cu Cu Cu Cu Cu The first interval P1 (μm) 277 299 98 98 180 The second interval P2 (μm) 4999 4977 598 998 4,999.8 Line width W(μm) 1 1 2 2 0.2 Height H(μm) 2 2 2 2 0.5 Area ratio (%) 1.02 0.39 2.33 2.20 1.00 Number of intersections (pieces/cm ² ) 200 200 1667 1000 1000 Affected area of disconnection (mm ² ) 0.50 0.50 0.06 0.1 0.1 evaluation result Surface resistance value (Ω/sq.) 3.1 9.3 1.5 1.5 12.3 Transmittance (550 nm) (%) 86.98 87.61 85.67 85.80 87.00 Internal Visibility and Phenomenon ◎ ◎ 〇 〇 ◎

[table 3] Comparative example 1 2 3 4 Transparent film Pattern type A A F F The distance between the recesses in the second direction (equivalent to P1) (μm) 1500 100 4855 100 The distance between the recesses in the first direction (equivalent to P2) (μm) 5000 5000 - - Conductive part Material Cu Cu Cu Cu The first interval P1 (μm) 1498 85 4800 98 The second interval P2 (μm) 4998 4985 - - Line width W(μm) 2 15 55 2 Height H(μm) 2 2 2 2 Area ratio (%) 0.17 15.26 1.13 2.0 Number of intersections (pieces/cm ² ) 13 200 0 0 Affected area of disconnection (mm ² ) 7.5 0.5 728 15 evaluation result Surface resistance value (Ω/sq.) 23.2 0.2 2.7 1.5 Transmittance (550 nm) (%) 87.83 72.75 86.87 86.0 Internal Visibility and Phenomenon 〇 X X ◎

The internal visibility and phenomenon of the conductive part of the heating film of Examples 1 to 16 were suppressed, and the transmittance (transparency) was high. In addition, it can be seen that the surface resistance value is within a specific range (0.003 to 70 Ω/sq.), so sufficient heat generation can be obtained when energized. In addition, it can be seen that the number of intersections is within a specific range (20 to 2500/cm ² ), so it is not easily affected by the disconnection of the conductive part, and the durability and reliability are high.

In addition, in the heating film of Example 10 with a line width slightly larger than 7 μm, compared with other examples with a line width of 1 to 3 μm, the internal visibility and phenomenon of the conductive part are slightly conspicuous (internal visibility and phenomenon evaluation result: △) . In addition, Examples 1 to 11, 14 and 15 using the same pattern A as the grid pattern are compared. The line width W of the conductive part is less than 2 μm, the first interval P1 is less than 300 μm, and the second interval P2 is less than 1000-5000 μm. The internal visibility and phenomenon of the conductive parts of Examples 1, 3, 6, and 7 are further It is suppressed (internal visibility and phenomenon evaluation result: ◎), and the transmittance is also high.

On the other hand, the first interval P1 of Comparative Example 1 is 1498 μm, which is relatively large, and the number of intersections is 13 points/cm ² , which is relatively small. Therefore, the area affected by the disconnection is large, which is 7.5 mm ² . From this result, it can be seen that the heating film of Comparative Example 1 is easily affected by the disconnection of the conductive portion, and has low durability and reliability. The line width of the conductive part of Comparative Example 2 is 15 μm, which is relatively large, so the internal visibility and phenomenon are significant (internal visibility and phenomenon evaluation result: ×). The line width of Comparative Example 3 is 55 μm, which is relatively large and has an L/S pattern (pattern F), so there is no intersection, and the area affected by the disconnection is large, 728 mm ² . Therefore, it can be seen that the internal visibility and phenomenon of the heating film of Comparative Example 3 are significant (internal visibility and phenomenon evaluation result: ×), and it is easily affected by the disconnection of the conductive part, and has low durability and reliability. In addition, it can be seen that although Comparative Example 4 has an L/S pattern, the line width is thin, so internal visibility and phenomenon can be suppressed (internal visibility and phenomenon evaluation: ◎), there is no intersection, and the area affected by the disconnection is large, 15 mm ^2. Therefore, it is easily affected by the disconnection of the conductive part, and the durability and reliability are low.

＜heating characteristic test＞ Regarding the heat generating films obtained in Examples 6, 7 and Comparative Example 4, the heating rate was measured by the following method. A 10 cm long linear electrode was formed on the end surface of the heating film (sample) cut into 10 cm square by silver paste as a connecting electrode for current flow in the first direction. In this way, the connecting electrodes are arranged at intervals of about 10 cm. Put the heating film (sample) into a constant temperature bath at -10°C, and apply a voltage of 5 V between the connecting electrodes for 40 seconds. The temperature of the sample before and after the voltage is applied is measured by the thermocouple installed in the sample. The temperature difference (rising temperature) before and after the voltage application of the heating film is divided by the application time of 40 seconds, and the value obtained is the heating rate of the heating film.

The heating rate of the heating film of Example 6 was 0.07°C/sec., and the heating rate of the heating film of Example 7 was 0.04°C/sec. These values are the sufficient heating rate of the heating film, and it can be confirmed that the heating films of Examples 5 and 7 have sufficient heating characteristics.

On the other hand, in the heating film obtained in Comparative Example 4, the conductive part was disconnected in the middle of the test, and the temperature increase rate could not be measured. [Industrial availability]

The heating film of the present invention can suppress the internal visibility and phenomenon of the conductive part, has high transparency (transmittance), and can obtain sufficient heat generation when energized. Therefore, it can be used as a heat-generating film that can efficiently heat the windows, mirrors, etc. of the vehicle without reducing the visual field of the vehicle driver and the design of the vehicle.

10: Heating film 11: Transparent film 11A: Slot 1 11B: Slot 2 11c: recess (groove) 11s: transparent film surface 12: Transparent resin layer 13: Conductive part 13A: The first conductive part 13AW: The first double line section 13B: The second conductive part 13BW: The second double line section 13s: The upper surface of the conductive part 13x: bulge 20: mold 20a: Convex part of mold 22: Coating layer 28: basal layer 33: Transparent supporting substrate D: Depth of recess H: Height of conductive part P1: first interval P2: second interval P4: 4th interval P5: 5th interval R: intersection W: Line width of conductive part

Fig. 1(a) is a view conceptually showing the cross-sectional structure of the heating film of the embodiment, and Fig. 1(b) is an enlarged view showing the cross-sectional structure near the conductive portion shown in Fig. 1(a). Fig. 2 is a diagram conceptually showing a plane of the heat generating film of the embodiment on which a grid pattern (pattern A) is formed. Fig. 3(a) is a diagram showing another embodiment in which the conductive portion protrudes from the surface of the heating film, and Fig. 3(b) is a diagram showing another embodiment in which the conductive portion is partially filled in the recess. Fig. 4 is a flow chart explaining the method of manufacturing the heating film of the embodiment. 5(a) to (c) are diagrams conceptually showing the steps of manufacturing a transparent film in a method of manufacturing a heat generating film. The transparent film is provided with a transparent resin layer with lattice-shaped recesses formed on the surface. Figures 6(a) to (c) are diagrams conceptually showing the steps required for electroless plating in the manufacturing method of the heating film. Fig. 7(a) is a diagram conceptually showing the plane of the heating film of another embodiment formed with a grid pattern (pattern D1), and Fig. 7(b) is a conceptual diagram showing a plane with a grid pattern (pattern D2) formed A plan view of the heating film of another embodiment. Fig. 8 is a view conceptually showing a plane of a heat generating film of another embodiment in which a grid pattern (pattern E) is formed. FIG. 9 is a diagram conceptually showing the plane of the previous heating film in which the line/space (L/S) pattern F is formed.

Claims (13)

A heating film, comprising: a transparent film having a plurality of first grooves extending in a first direction and a plurality of second grooves extending in a second direction crossing the first direction on the surface; and a conductive part, It exists in the first and second grooves; the line width of the conductive part is 0.2-10 μm, the height of the conductive part is 0.5-10 μm, and it exists between the two adjacent first grooves. The interval is 20-1000 μm, the number of intersections between the above-mentioned conductive part in the first groove and the above-mentioned conductive part in the second groove is 20-2500/cm ² , and the area ratio of the above-mentioned conductive part It is 0.1 to 10%. The heat generating film of claim 1, wherein the light transmittance of the heat generating film at a wavelength of 550 nm is 60-98%. Such as the heating film of claim 1, wherein the surface resistance of the heating film is 0.003～70 Ω/sq. The heating film of claim 1, wherein the interval between the above-mentioned conductive parts existing in two adjacent second grooves in the first direction is 1000-15000 μm. Such as the heating film of claim 1, wherein the second direction is orthogonal to the first direction. For example, the heating film of claim 1, which has a plurality of first multi-line parts composed of conductive parts existing in a plurality of first grooves, The two adjacent first multi-line parts are arranged at a first interval of 20～1000 μm, The plurality of conductive parts constituting the first multi-line part are arranged at a fourth interval smaller than the first interval. Such as the heating film of claim 6, wherein the fourth interval is 0.2-20 μm. For example, the heating film of claim 1, which is provided with a plurality of second multi-line portions composed of conductive portions existing in a plurality of second grooves, The two adjacent second multi-line parts are arranged at a second interval in the first direction, The plurality of conductive parts constituting the second multi-line part are arranged at a fifth interval smaller than the second interval in the first direction. Such as the heating film of claim 8, wherein the fifth interval is 0.5-20 μm. A method for manufacturing a heating film, which is a method for manufacturing the heating film according to any one of claims 1 to 9, and includes the following steps: Prepare the above-mentioned transparent film with a first groove and a second groove on the surface; and The first groove and the second groove are filled with a conductive material to form the above-mentioned conductive portion. The method of manufacturing a heat generating film according to claim 10, wherein the step of preparing the transparent film includes the steps of: forming a first groove on the transparent film by imprinting using a mold having a concave-convex pattern corresponding to the conductive portion; Slot 2. The method for manufacturing a heating film of claim 11, wherein the transparent film has a transparent supporting substrate and a transparent resin layer formed on the transparent supporting substrate, The steps of preparing the above transparent film include the following steps: Prepare the above-mentioned mold having a concave-convex pattern corresponding to the above-mentioned conductive part; Coating a photocurable resin on the surface of the mold with the concave-convex pattern to form a coating layer; Disposing the above-mentioned transparent supporting substrate on the above-mentioned coating layer; Irradiating ultraviolet light from the side of the transparent support substrate to harden the coating layer to form the transparent resin layer; and The mold is peeled off from the transparent resin layer. The method of manufacturing a heating film of claim 10, wherein the conductive portion is formed by electroless plating.

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