JP7121513B2 - film heater - Google Patents

Description

The present invention relates to a film heater, and more particularly to a film heater in which a conductive pattern electrically connectable to an external power source is provided on a film.

Conventionally, a film-like planar heating element with a conductive pattern for heating, which is used by attaching it to an object to be heated, for the purpose of preventing ice and snow adhesion, melting snow, preventing fogging, heat retention, etc. It has been known.

For example, Patent Document 1 discloses a planar heating element in which a bare nichrome wire processed into an arbitrary shape is disposed inside two multilayer composite films via an adhesive layer made of an insulating material. , the planar heating element is attached to an object to be heated using a double-sided adhesive tape, a double-sided adhesive film, or the like.
Patent Document 2 discloses a semi-cured sheet for manufacturing a rigid sheet-shaped heating element, which has a planar heat-generating portion having flexibility and a semi-cured semi-cured resin coating layer formed to enclose the heat-generating portion. is disclosed. The semi-cured resin coating layer containing the heat-generating part is in a semi-cured state (B stage), has flexibility and plasticity, and has adhesiveness on the surface, so it can be applied to any shape of the adherend. It is described that it can be followed and pasted.

In Patent Document 3, a metal wire resistor formed in a predetermined pattern is provided on or inside a circular sheet-like flexible transparent substrate having a fan-shaped notch with a central angle of 90 degrees or less. A planar heater for a signal lamp is disclosed, wherein the linear portions of the fan-shaped cutouts are brought into contact or close to each other to deform the flexible transparent substrate from a circular sheet to a conical sheet shape. , it is described that even if the display window of the signal lamp is dome-shaped, it is easy to adhere to it.

JP-A-2003-257597 JP 2006-278138 A JP 2017-004918 A

In the invention disclosed in Patent Document 1, a bare nichrome wire is disposed inside between two multilayer composite films using a wiring fixing adhesive layer, and the peripheral portion of the multilayer composite film is heat-sealed. , the configuration is complex.
The invention disclosed in Patent Document 2 requires the use of a special resin coating, requires special equipment such as complete curing of the semi-cured resin coating layer by a photo-curing method, and tends to complicate the construction method.
The invention disclosed in Patent Document 3 is effective when the display window of the signal lamp has a dome shape, but it is difficult to use otherwise.

SUMMARY OF THE INVENTION An object of the present invention is to provide a film heater which is easy to manufacture and can be easily adhered to an adherend having an uneven shape without impairing the design of the adherend. and

In the present invention, a conductive pattern made of conductive wires is provided on one surface of a support sheet made of a transparent thermoplastic resin sheet, and the conductive pattern includes connection terminal portions and lead wires extending from the connection terminal portions. and a heater portion continuing from the lead wire are provided as a continuous linear pattern made of a single conductive wire.
In the present invention, it is preferable that the connection terminal portion has a pattern in which the conductive wire is bent at a plurality of locations, for example, a meander shape in which the conductive wire is bent at a plurality of locations and meanders.

In the present invention, an exterior sheet made of a transparent thermoplastic resin sheet different from the support sheet is provided on the surface of the support sheet provided with the conductive pattern so as to cover the conductive pattern, The exterior sheet may be a film heater provided with a through hole for exposing at least a part of the connection terminal portion to the outside.
In the present invention, a metal plate can be further provided on the connection terminal portion.
In the present invention, the conductive wires forming the conductive pattern may be coated with a self-bonding insulating coating except for the connection terminal portion. An adhesive layer may be provided on the surface opposite to the surface where the adhesive layer is applied.

The film heater according to the present invention is a transparent film heater as a whole, and can be attached to various adherends without impairing the design of the adherend to be heated. In addition, by using a thermoplastic resin sheet for the support sheet and, if present, the exterior sheet, it is possible to easily adhere to an adherend having an uneven shape. When the body is a resin molded body, in-mold transfer is possible, in which a film heater can be formed on the surface of the resin molded body at the same time as the resin molding. In addition, since the conductive pattern is composed of a single conductive wire, the conductive pattern can be continuously formed with a single conductive wire, which facilitates production, and the entire surface of the support sheet on which the conductive pattern is formed can be covered with the exterior sheet. , it becomes possible to protect the conductive pattern.

INDUSTRIAL APPLICABILITY The present invention is a film heater having good moldability, high mechanical strength, and excellent adhesiveness to adherends, and can be applied to various purposes such as preventing ice and snow from sticking, melting snow, preventing fogging, and retaining heat. For example, it can be applied to automobile headlights, motorcycle grips and seats, outdoor lights and traffic signals.

(a) is a plan view schematically showing an example of the film heater of the present invention, and (b) is a sectional view thereof. (a) is a plan view schematically showing an example of an exterior sheet that can be used in the present invention, and (b) is a cross-sectional view thereof. (a) is a plan view schematically showing an example of the film heater of the present invention using an exterior sheet, and (b) is a sectional view thereof.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1(a) is a plan view schematically showing an example of the film heater of the present invention. FIG. 1(b) is a sectional view schematically showing an example of the film heater of the present invention.
According to FIG. 1, a support sheet 1 made of a transparent thermoplastic resin sheet is provided with a conductive pattern 2 made of conductive lines on one side. The conductive pattern 2 includes a pair of left and right connection terminal portions 21a and 21b, lead wires 22a and 22b extending from the connection terminal portions 21a and 21b, respectively, and a heater portion 23 continuing from the lead wires 22a and 22b. is provided as a continuous linear pattern of conductive lines. As in this embodiment, the heater section as a whole may be non-linear.

The support sheet used in the film heater of the present invention is made of a transparent thermoplastic resin sheet. Thereby, a transparent film heater as a whole can be preferably produced. A film heater that is transparent as a whole can be attached to various adherends without impairing the design of the adherend to be heated.
In addition, by using a thermoplastic resin sheet, it can be easily attached to an adherend having an uneven shape. A film heater can be formed on the surface of the resin molding by molding methods such as molding, laminate molding, in-mold molding, and insert molding.

As the thermoplastic resin sheet, ethylene-based resin, propylene-based resin, polyolefin-based resin, thermoplastic polyester-based resin, polyamide-based resin, polyvinyl chloride, polycarbonate, ABS resin, etc. can be used, and two or more of these can be used. It may be something to do. In particular, it is preferable to use a polypropylene-based resin which is excellent in moldability, mechanical strength, flexibility and weather resistance.
Inorganic fine powders or organic fillers, dispersants, antioxidants, compatibilizers, UV stabilizers, antiblocking agents, antistatic agents and the like can be added to the thermoplastic resin sheet as appropriate.
The thickness of the thermoplastic resin sheet is preferably 0.030 mm to 1.000 mm, more preferably 0.100 mm to 0.700 mm.

The conductive pattern can also be formed by printing using conductive ink such as silver paste or by etching metal foil such as copper foil. When forming a conductive pattern, forming a circular conductive wire having a constant diameter in a cross section in a predetermined pattern facilitates formation of the heater portion, the lead portion, and the connection terminal portion as one continuous line. It is preferable in that it can be done.
When the conductive pattern is composed of a conductive wire, the conductive wire preferably includes at least a metal wire, and more preferably, the metal wire is covered with a self-bonding insulating film. can do. As the metal wire, for example, metal wires of copper, iron, gold, copper-nickel, nickel-chromium, iron-nickel-chromium, etc. can be used, but other materials can also be used as long as they have conductivity. From the viewpoint of electric resistance, durability and cost, it is preferable to use copper or a copper alloy in which copper is combined with zinc, lead, tin, silver, aluminum, nickel, beryllium, zirconium or the like singly or in combination.

The insulating coating covering the metal wire is an insulating resin coating, and the conductive wire covered with the insulating coating can be a commercially available enamel wire. Specific examples of the insulating resin film include polyester, polyethylene, polyurethane, polyvinyl chloride, polyamide, polyimide, polyesterimide, polyamideimide, fluororesin, and the like. The insulating coating is typically black, but may be colored in any color to match the color of the adherend to be heated.
The diameter of the conductive wire forming the conductive pattern is, for example, 0.03 mm to 0.20 mm. Although it may not be easy to form a thin conductive wire, the conductive wire should be as thin as possible in order not to impair the design of the object to be heated. 05 mm to 0.15 mm. The length of the conductive line can be determined according to the pattern form of the conductive pattern and the like.

The conductive pattern can typically be formed by drawing a predetermined pattern form by drawing a conductive line on the support sheet, and fixing the conductive line by embedding it in at least the surface of the support sheet.
As a method for embedding the conductive wires in the surface of the support sheet, it is desirable to embed the conductive wires in the surface of the support sheet by utilizing the principle of ultrasonic fusion. When performing ultrasonic fusion, a wiring drawing apparatus capable of embedding the conductive wires in the surface of the supporting sheet by melting the surface of the support sheet made of thermoplastic resin while drawing out the conductive wires can be used. With the ultrasonic head provided in such a wiring drawing apparatus, the conductive wires can be embedded in the surface of the support sheet by vibrating and applying pressure while drawing out the conductive wires onto the surface of the support sheet.
By embedding the conductive wires in the surface of the support sheet, the conductive pattern can be positioned on the support sheet, and displacement of the conductive wires due to external impact or the like can be suppressed. Further, by embedding the conductive wires in the surface of the support sheet, it is possible to reduce the degree of unevenness of the surface of the support sheet caused by arranging the conductive wires on the surface of the support sheet.

Next, an embodiment of the conductive pattern of the film heater of the present invention will be described.
Referring to FIG. 1, the conductive pattern 2 includes a pair of left and right connection terminal portions 21a and 21b, lead wires 22a and 22b extending from the connection terminal portions 21a and 21b, respectively, and the lead wires 22a and 22b as a whole. A non-linear heater portion 23 is provided as a continuous linear pattern composed of a single conductive wire.
By forming the connection terminal portion, the lead wire, and the heater portion with a single continuous conductive wire, the manufacturing process can be facilitated, and a low-cost film heater can be manufactured.
In FIG. 1, the connection terminal portions 21a and 21b are formed in a meandering shape in which the conductive wire is bent at a plurality of points and meanders. In this case, it is preferable that the connecting terminal portions 21a and 21b are bent at a plurality of points and meandering, and the number of folds of the folded portion is increased within a predetermined plane area so that the folded lines are densely packed. In the case of the embodiment shown in FIG. 1, the meander shape repeats a relatively short bent portion and a relatively long straight portion, and the number of the straight portions is 2/mm or more. It is preferable that

In addition, if necessary, a conductive piece made of a metal plate can be further provided on the connection terminal portion in order to increase the connection efficiency with the external electrode. As the metal plate, for example, copper, a copper alloy, iron, an iron-nickel alloy, or the like can be used.
When the conductive wire is covered with an insulating film, the insulating film covering the conductive wire of the connection terminal portion is removed to expose the metal wire inside. As a method of exposing, cutting with a milling machine or the like is possible, but the insulating coating can also be melted and removed by heat when soldering to the metal plate or the external electrode.

The heater portion 23 is formed by being routed from lead wires 22a and 22b extending from a pair of left and right connection terminal portions 21a and 21b, respectively. , and a relatively long linear portion are repeated, and the pattern is bent at a plurality of points to meander, forming a non-linear linear pattern as a whole. The pattern of the heater portion can be an arbitrary pattern in consideration of the shape of the adherend, the heating area, and the heating efficiency, and may be a repeating curved shape or a spiral shape that does not include linear portions.
In FIG. 1, the conductive pattern consists of a pair of left and right connection terminal portions 21a and 21b and a pair of left and right lead portions 22a and 22b centered on the heater portion 23. A lead wire 22a is extended from the other end of the connection terminal portion 21a, and a heater portion 23 is formed by a conductive wire drawn around from the lead wire 22a. The other lead wire 22b is extended from the portion 23, and a single conductive wire continuing to the other connection terminal portion 21b forms one continuous linear heater portion 23, lead portion 22, and connection terminal portion 21. It is

In another embodiment of the present invention, the surface of the support sheet provided with the conductive pattern is provided with an exterior sheet made of another transparent thermoplastic resin sheet covering the conductive pattern, and the exterior sheet includes the connection terminal portion can be a film heater provided with a through hole for exposing at least part of the outside.

FIG. 2(a) is a plan view schematically showing an example of an exterior sheet that can be used in the present invention. FIG.2(b) is sectional drawing which shows typically an example of the exterior|packing sheet which can be used for this invention.
In FIG. 2, the exterior sheet 3 having substantially the same shape as the supporting sheet of the film heater is provided with a through hole 31 for exposing at least a part of the connection terminal portion of the film heater to the outside.

A thermoplastic resin sheet similar to the support sheet can be used for the exterior sheet, and the exterior sheet can be laminated by subjecting the surface of the support sheet on which the conductive pattern is formed to heat treatment and/or press treatment. . For bonding, if necessary, an adhesive layer, an adhesive layer, a heat-seal layer, or the like may be interposed between the support sheet and the exterior sheet. On the exterior sheet, at least a portion of the connection terminal portion is exposed to the outside. A through hole is provided. For the formation of through-holes in the exterior sheet for exposing the connection terminal portions, punching with a mold or cutting means such as a laser device can be used. A milling device or the like can be used.

FIG. 3(a) is a plan view schematically showing an example of the film heater of the present invention using an exterior sheet. FIG. 3(b) is a cross-sectional view schematically showing an example of the film heater of the present invention using an exterior sheet.
As can be seen from the embodiment shown in FIG. 3, the entire surface of the support sheet 1 on which the conductive pattern is formed is covered with the exterior sheet 3 except for the through holes 31, so that the thermoplastic resin sheet as a whole is transparent. Even with a configuration in which a conductive pattern made of a conductive wire is sandwiched between the support sheet 1 and the exterior sheet 3, the connection terminal portion 21 can be electrically connected to the external power source reliably. Also, the heater section and the lead section on the surface of the support sheet can be covered and protected by the exterior sheet.
An antifouling layer, an antifogging layer, an antistatic layer, a hard coat layer, and the like may be formed on the surface of the exterior sheet, if necessary.

In the present invention, if necessary, a configuration in which an adhesive layer is provided on the surface of the support sheet opposite to the surface on which the conductive pattern is provided can be employed. By using the adhesive layer, it can be easily attached to an adherend having an uneven shape. As the adhesive layer, for example, adhesives such as acrylic, urethane, epoxy, rubber, polyester, cellulose, and emulsion can be used. In addition, if necessary, fillers, tackifiers, curing agents, and the like can be appropriately used as additives for improving the properties of the pressure-sensitive adhesive.
The thickness of the adhesive layer is not particularly limited as long as it has a thickness that provides adhesive strength, and is usually 20 μm to 200 μm, preferably about 25 μm to 75 μm. When forming the adhesive layer, the adhesive can be formed using a coating method such as gravure coating, gravure reverse coating, comma coating, knife coating, and die coating.

(Example 1)
A thermoplastic resin sheet (Mitsubishi Plastics Co., Ltd. polycarbonate sheet DPI-AO thickness 0.075 mm) is prepared as a support sheet, and a conductive wire (ELEKTRISOLA self-bonding coated conductive wire AB15φ0.10 mm) is placed on the surface of the support sheet. A wiring drawing apparatus (WCE150 manufactured by Ruhlamat, setting conditions: USP1200, speed 40%) equipped with an ultrasonic head was used for embedding to form a conductive pattern as shown in FIG.
In the conductive pattern, the length of the lead portion (the length of the linear portion from the terminal portion to the first folded position) is 130 mm. The number of lines was 8 times, and the connecting terminal portion was made to have a straight portion of 17 mm, a folded portion (pitch) of 0.3 mm, and the number of folded times (the number of lines of the straight portion) of 12 times. Finally, it was cut into a size of 170 mm long×120 mm wide to produce a film heater.

(Example 2)
A thermoplastic resin sheet (Mitsubishi Plastics, Inc., polycarbonate sheet DPI-AO, thickness 0.075 mm) was prepared as an exterior sheet, and through holes of 10 mm×10 mm were formed at positions corresponding to the connection terminal portions. An exterior sheet is attached to the surface of the support sheet on which the conductive pattern of Example 1 is wired, and a vacuum laminator (MVLP-500 manufactured by Meiki Seisakusho, temperature 180 ° C., pressure 0.5 MPa) is used to heat press the support sheet. sufficiently adhered to the top. Finally, it was cut into a size of 170 mm long×120 mm wide to produce a film heater.

Reference Signs List 1 Support sheet 2 Conductive patterns 21a, 21b Connection terminal portions 22a, 22b Lead portion 23 Heater portion 3 Exterior sheet 31 Through hole

Claims (5)

A conductive pattern made of conductive wires is provided on one surface of a support sheet made of a transparent thermoplastic resin sheet, and the conductive pattern includes connection terminal portions, lead wires extending from the connection terminal portions, and The heater part continuing from the lead wire is provided as a continuous linear pattern consisting of a single conductive wire , and the connection terminal part is formed of a pattern in which the conductive wire is bent at a plurality of points. film heater. An exterior sheet made of a transparent thermoplastic resin sheet different from the support sheet is provided on the surface of the support sheet on which the conductive pattern is provided so as to cover the conductive pattern, and the exterior sheet is provided with a transparent thermoplastic resin sheet. 2. The film heater according to claim 1, further comprising a through hole for exposing at least part of said connection terminal portion to the outside. 3. The film heater according to claim 1, wherein a metal plate is further provided on said connection terminal portion. 4. The film heater according to any one of claims 1 to 3 , wherein the conductive wires forming the conductive pattern are coated with a self-bonding insulating coating except for the connection terminal portions. 5. The film heater according to any one of claims 1 to 4 , wherein an adhesive layer is provided on the side of the support sheet opposite to the side on which the conductive pattern is provided.

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