JP2007052944A - Planar exothermic body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar exothermic body in which manufacturing is made easier in which shape is stabilized and in which performance and quality are improved by adding an electric insulating substrate having elasticity, while using the electric insulating substrate having flexibility. <P>SOLUTION: A means of limiting elasticity in the same direction as a screen printing direction of an electrode and a polymer resistor 14 is arranged and installed at the electric insulating substrate 12 having flexibility, and a means of limiting elasticity in the same direction as the roll direction is arranged and installed at the roll shaped electric insulating base material 12. By this, the electric insulating substrate 12 can use a raw material having flexibility, and can improve manufacturing characteristics while retaining flexibility. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heating element that can be used as a heat source for heating, heating, drying, and the like.

  Conventionally, in the heat generating part of this type of planar heating element, a base polymer and a conductive material such as carbon black, metal powder, and graphite are dispersed in a solvent. (For example, see Patent Documents 1, 2, and 3).

  4 is a plan view of a conventional sheet heating element having PTC characteristics, FIG. 5 is a cross-sectional view taken along line xy of FIG. 4, and FIG. 6 is a schematic cross-sectional view at the time of manufacture. As shown in FIGS. 4 and 5, the planar heating element includes a pair of comb-shaped electrodes 51 and 52 obtained by printing and drying a conductive paste on an electrically insulating substrate 50 such as a polyester sheet. The polymer resistor 53 obtained by printing and drying the polymer resistor ink is provided at a position where power is supplied, and the comb-shaped electrodes 51 and 52 and the high The molecular resistor 53 is covered and protected.

  When a polyester film is used as the base material 50 and the covering material 54, for example, a polyethylene-based heat-fusible resin 55 is bonded to the covering material 54 in advance, and pressurizing while applying heat (pressing during heating). The base material 50 and the covering material 54 are joined via the heat-fusible resin 55. Thereby, the comb-shaped electrodes 51 and 52 and the polymer resistor 53 are isolated from the outside world, and long-term reliability is imparted. As a means for pressurization at the time of heating, a schematic configuration sectional view when the covering material 54 is bonded is shown in FIG. 6, but a laminator 58 including two heating rolls 56 and 57 is generally used.

The PTC characteristic is a resistance temperature characteristic in which the resistance value increases as the temperature rises, and when the temperature reaches a certain temperature, the resistance value rapidly increases (takes the initial letter of English Positive Temperature Coefficient) The polymer resistor 53 having PTC characteristics can provide a planar heating element having a self-temperature adjusting function.
Japanese Patent Laid-Open No. 56-13689 JP-A-6-96843 JP-A-8-120182

  However, in the above-described conventional configuration, the comb-shaped electrodes 51 and 52 and the polymer resistor 53 printed on the electrically insulating base material 50 such as a polyester sheet are protected by the same electrically insulating coating material 54, and thus the basic structure is used. Depending on the material 50 and the thickness of the covering material 54 and its thickness, it lacks flexibility, and when this planar heating element is used for a car seat heater (car seat), it was used for a seating feeling or a handle heater. There was a problem that the touch feeling in the case was impaired.

  Therefore, in order to provide flexibility, if the electrically insulating base material 50 such as a polyester sheet or the electrically insulating coating material 54 is made thin or made of a soft material, it becomes difficult to manufacture, and productivity is lacking. There was a drawback that the quality was not stable.

For example, if the electrically insulating base material 50 is made very thin so as to have flexibility or is made of a soft material, the strength of the base material 50 itself is extremely lost. Since the ink and the printing plate cannot be pressed against the electrically insulating base material 50 with a predetermined printing pressure, they are smeared or chipped, and there has been a concern that the performance of the sheet heating element will not be stable. In addition, after printing a conductive paste or polymer resistor ink, it tends to cause wrinkles due to thermal shrinkage when dried, so the shape is not stable and the performance and quality of the planar heating element may be deteriorated. there were. Therefore, in order to mechanically increase the strength of the electrically insulating base material 50, when a tension is applied to the electrically insulating base material 50, the electrical insulating base material 50 is greatly stretched by the tension, and is also stretched when the tension is removed. As a result, the shape was not stable, and the performance and quality of the planar heating element deteriorated.

  In particular, in a planar heating element produced by a continuous screen printing method in which an electrode and a polymer resistor are continuously formed by screen printing while winding a roll-shaped electrically insulating substrate 50 into a roll shape, In order to continuously print and dry the sheet heating element, the tension is applied while the electrically insulating base material 50 is held for a long time, so the tension per unit width must be increased. When the base material 50 has flexibility, there is a problem that the shape is not more stable and the performance and quality of the planar heating element deteriorate.

  In view of the problems of the prior art, the problem to be solved by the present invention is a means for limiting stretchability to an electrically insulating substrate while using a flexible electrically insulating substrate for a planar heating element. It is to make manufacturing easier and to stabilize the shape and improve the performance and quality performance of the planar heating element.

  In order to solve the above-described problems, a planar heating element of the present invention includes a flexible electrically insulating substrate, electrodes formed by screen printing on the electrically insulating substrate, and a high power supplied by the electrodes. In a planar heating element comprising a molecular resistor and a covering material that covers the electrode and the polymer resistor and is disposed in close contact with the electrically insulating substrate, the electrode and the high electrode are disposed on the electrically insulating substrate. A protective layer having means for limiting the stretchability in the same direction as the screen printing direction of the molecular resistor is provided.

  In addition, the electrode and the electrode produced by continuous screen printing method in which the electrode and the polymer resistor are continuously formed by screen printing while winding the roll-like electrically insulating base material in a roll shape. In a planar heating element that covers a polymer resistor and includes a covering material disposed in close contact with the electrically insulating base material, the electrically insulating base material is limited in stretchability in the same direction as the roll direction. A protective layer having means is provided.

  According to the configuration described above, means for limiting the stretchability in the same direction as the screen printing direction of the electrode and polymer resistor to the flexible electrically insulating substrate, or the roll to the roll-like electrically insulating substrate Since a protective layer having means for restricting the stretchability in the same direction as the direction is disposed, the electrically insulating base material can be made of a flexible material, while maintaining the flexibility, It becomes possible to improve manufacturing.

  In other words, the protective layer having a means for limiting the stretchability only needs to have strength in one direction of the screen printing direction or the roll direction, and thus has flexibility such as long fibers arranged in alignment in the limitable stretch direction. Since the strength may be increased in only one direction, the thickness can be extremely reduced, and the electrically insulating substrate including the protective layer can maintain flexibility. And since the protective layer has means for limiting the stretchability, the electrical insulating substrate including the protective layer is mechanically strengthened by applying a tension in the same direction as the screen printing direction or the roll direction during printing and drying. Since it can increase, the shape change at the time of printing and drying can be suppressed, and the performance and quality of a planar heating element can be improved.

  The planar heating element of the present invention can use a material having flexibility as an electrically insulating base material for forming electrodes and polymer resistors by screen printing, making manufacturing easier and improving productivity, It is possible to improve the usability and reliability of a device using a planar heating element.

  According to a first aspect of the present invention, there is provided an electrically insulating substrate having flexibility, an electrode formed by screen printing on the electrically insulating substrate, a polymer resistor fed by the electrode, and the electrode and the polymer resistor. In a sheet heating element comprising a covering material that covers a body and is disposed in close contact with the electrically insulating substrate, the electrode and the polymer resistor have the same direction as the screen printing direction on the electrically insulating substrate. It is a planar heating element provided with a protective layer having means for limiting stretchability.

  The second invention is produced by a continuous screen printing method in which an electrode and a polymer resistor are continuously formed by screen printing while winding an electrically insulating base material having roll-like flexibility into a roll shape. And a sheet heating element covering the electrode and the polymer resistor and provided with a covering material disposed in close contact with the electrically insulating base material, the electrically insulating base material extending and contracting in the same direction as the roll direction. It is a planar heating element provided with a protective layer having means for limiting the properties.

  By adopting the above configuration, a means for limiting the elasticity of the electrode and polymer resistor in the same direction as the screen printing direction to the flexible electrically insulating substrate, or a roll-shaped electrically insulating substrate Since a protective layer having a means for restricting the stretchability in the same direction as the roll direction is disposed on the substrate, it is possible to use a material having flexibility as the electrically insulating base material, thereby maintaining flexibility. However, it will be possible to improve manufacturing.

  In other words, the protective layer having a means for limiting the stretchability only needs to have strength in one direction of the screen printing direction or the roll direction, and thus has flexibility such as long fibers arranged in alignment in the limitable stretch direction. Since the strength may be increased in only one direction, the thickness can be extremely reduced, and the electrically insulating substrate including the protective layer can maintain flexibility. And since the protective layer has means for limiting the stretchability, the electrical insulating substrate including the protective layer is mechanically strengthened by applying a tension in the same direction as the screen printing direction or the roll direction during printing and drying. Since it can increase, the shape change at the time of printing and drying can be suppressed, and the performance and quality of a planar heating element can be improved.

  The sheet heating element according to the third invention is a long fiber in which the protective layer that restricts the stretchability of the electrically insulating base material having flexibility according to the first and second inventions is particularly aligned in the stretch direction to restrict. It is the structure formed by.

  And since the protective layer is formed of long fibers aligned in the restricting expansion and contraction direction, it has sufficient strength in the direction of the long fibers while having flexibility, and its thickness can be made extremely thin. It is possible to limit the stretchability of the electrically insulating substrate by integrating the protective layer with the electrically insulating substrate, and it is necessary for manufacturing without impairing the flexibility of the electrically insulating substrate. Strength can be improved.

  The planar heating element of the fourth invention, in particular, the protective layer for limiting the stretchability of the electrically insulating base material of the third invention is formed by long fibers arranged in alignment in the restricting stretch direction, and The long fibers forming the protective layer are formed so as to be entangled with the fibers forming the electrically insulating base material and integrated with the electrically insulating base material.

And in addition to the effect of 3rd invention, the long fiber which forms a protective layer is formed so that it may entangle with the fiber which forms the electrically insulating base material which has flexibility, and is integrated with the electrically insulating base material Therefore, the adhesive strength between the protective layer and the electrically insulating substrate can be increased, and there is no concern that the protective layer and the electrically insulating substrate are peeled off for some reason, and the protective layer is formed. Since the fibers forming the electrically insulating substrate are entangled with the long fibers and become three-dimensional, the integrated protective layer and the flexibility of the electrically insulating substrate can be further obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 to 3 are schematic configuration diagrams of a sheet heating element according to Embodiment 1 of the present invention. FIG. 1 is a plan view, FIG. 2 is a schematic perspective view, and FIG. FIG.

  1 and 2, the electrically insulating base material 12 having flexibility restricts expansion and contraction of the electrically insulating base material 12 on one surface of the flexible polyester nonwoven fabric 12a, and is aligned in the direction of expansion and contraction. A protective layer 12b formed of the long fibers is disposed, and a thin base film 12C such as a polyester film is laminated on the opposite surface.

  The sheet heating element 11 is printed with a pair of electrodes 13 formed by printing and drying a silver paste on the base film 12C of the electrically insulating base 12, and a polymer resistor ink so as to overlap the electrodes 13. The polymer resistor 14 formed by drying is formed. Then, the electrode 13, the polymer resistor 14, and the electrically insulating base material 12 and an adhesive resin layer 15 such as an acrylic adhesive having adhesiveness are formed on a thin-walled electrically insulating film such as a polyester film previously formed. The covering material 16 laminated with the coating material is bonded together.

  The electrode 13 is provided with wide main electrodes 13a and 13b so as to be opposed to each other, and a plurality of comb-shaped branch electrodes 13c and 13d are alternately provided from the respective main electrodes 13a and 13b, and overlap each other. By supplying power from the branch electrodes 13c and 13d to the polymer resistor 14 arranged as described above, a current flows through the polymer resistor 14 to generate heat. This polymer resistor 14 has PTC characteristics, and when the temperature rises, the resistance value of the polymer resistor 14 rises and has a self-temperature adjusting function so as to reach a predetermined temperature, so that temperature control is unnecessary. Thus, it has a function as a highly safe planar heating element.

  Here, as the order of the processing steps, first, the polyester nonwoven fabric 12a is protected together in the process of manufacturing by the hydroentanglement method (nonwoven fabric production method in which polyester fibers are entangled with water current without being woven: details are omitted). The long fibers which become the layer 12b are entangled, and the polyester nonwoven fabric 12a and the protective layer 12b are integrated into a roll-like one disposed on one surface, and this roll-like one is on the surface opposite to the protective layer 12b. A thin base film 12C such as a polyester film is laminated to prepare an electrically insulating base 12, and the electrically insulating base 12 is formed from long fibers arranged in a stretch restricting direction. Expansion and contraction is restricted in the roll direction by the protective layer 12b.

Next, as shown in FIG. 3, the screen printing direction is the same as the winding direction on the base film 12 </ b> C of the electrically insulating substrate 12 while winding the rolled electrically insulating substrate in a roll shape. In a continuous screen printing method in which electrodes and polymer resistors are continuously formed by screen printing, a pair of electrodes 13 is formed by printing and drying silver paste, and polymer resistor ink is applied so as to overlap the electrodes 13. The polymer resistor 14 is formed by printing and drying. The electrode 13 and the roll-shaped electrical insulating substrate 12 on which the polymer resistor 14 is formed and the adhesive resin layer 15 such as an acrylic adhesive having adhesiveness are formed in advance, such as a polyester film. A plurality of heating element main body parts are completed by continuously laminating a covering material 16 laminated with a thin-walled electrically insulating overcoat material, and this completed product is formed into a sheet-like outer lead wire, etc. Post-processing is done to finish the final product.

  Here, the electrically insulating substrate 12 is restricted in expansion and contraction in the roll direction of the electrically insulating substrate 12 by a protective layer 12b formed from long fibers aligned in the expansion and contraction restricting direction. Since the screen printing direction of the electrode 13 and the polymer resistor 14 is in the same direction as the roll direction of the electrically insulating substrate 12, the electrically insulating substrate 12 can be made of a flexible material. As a result, it is possible to improve manufacturing while maintaining flexibility.

  That is, the protective layer 12b having a means for restricting the stretchability of the electrically insulating substrate 12 only needs to have strength in one direction of the screen printing direction or the roll direction of the electrically insulating substrate 12, and therefore the stretching direction to be restricted. A material having flexibility such as long fibers arranged in a uniform manner may be used, and the strength is increased only in one direction. Therefore, the thickness can be extremely reduced, and the electrically insulating substrate 12 including the protective layer 12b is flexible. Sex can be maintained.

  And since the protective layer 12b has a means for restricting stretchability, when the electrode 13 and the polymer resistor 14 are printed and dried on the electrically insulating substrate 12 including the protective layer 12b, the screen printing direction or the roll direction is set. By applying tension in the same direction, the strength can be increased mechanically, so that shape change during printing and drying can be suppressed, and the performance and quality of the planar heating element 11 can be improved. become.

  In addition, since the protective layer 12b is formed of long fibers arranged in a restricting expansion / contraction direction, the long fiber has sufficient strength in the direction while having flexibility, and its thickness is also extremely thin. By integrating the protective layer 12b with the electrically insulating substrate 12, the stretchability of the electrically insulating substrate 12 can be limited, and the flexibility of the electrically insulating substrate 12 is not impaired. In addition, the strength required for manufacturing can be improved.

  Furthermore, since the long fibers forming the protective layer 12b are formed so as to be entangled with the fibers forming the electrical insulating base material 12 and integrated with the electrical insulating base material 12, the protective layer 12b and the electrical insulating group The adhesive strength of the material 12 can be increased, and there is no concern that the protective layer 12b and the electrically insulating base material 12 will be peeled off for some reason, and the long fibers forming the protective layer 12b are electrically insulated. Since the fibers forming the conductive base material 12 are intertwined and become three-dimensional, the flexibility of the integrated protective layer 12b and the electrically insulating base material 12 can be further obtained.

  In the first embodiment, the example in which the long fibers that become the protective layer 12b are entangled together in the process of manufacturing the electrically insulating substrate 12 by the hydroentanglement manufacturing method has been described. The long fibers to be the protective layer 12b may be bonded to the layer 12 by hot embossing, and the other components may have any configuration as long as the object of the present invention is achieved.

  As described above, the present invention is a sheet-like heating element made of a flexible material and has flexibility, so that it can be applied to an automobile seat, steering wheel, or other appliance that requires heating as a heater for heating. it can.

The top view which shows the structure of the planar heating element in Embodiment 1 of this invention Schematic perspective view of the same heating element Schematic diagram of the process when printing on the same heating element The top view which shows the structure of the conventional planar heating element Cross-sectional view of coplanar heating element Cross-sectional view showing a conventional sheet heating element

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Planar heating element 12 Electrically insulating base material 12a Polyester nonwoven fabric 12b Protective layer 12C Base material film 13 Electrode 14 Polymer resistor 16 Coating material

Claims (4)

An electrically insulating base material having flexibility, an electrode formed by screen printing on the electrically insulating base material, a polymer resistor fed by the electrode, and the electrical insulation covering the electrode and polymer resistor body In the sheet heating element provided with a covering material disposed in close contact with the conductive substrate, means for limiting stretchability in the same direction as the screen printing direction of the electrode and polymer resistor on the electrically insulating substrate A planar heating element provided with a protective layer having The electrode and polymer are produced by a continuous screen printing method in which an electrode and a polymer resistor are continuously formed by screen printing while winding a roll-like electrically insulating base material in a roll shape. A sheet heating element comprising a covering material disposed in close contact with the electrical insulating base material so as to cover a resistor, and means for limiting the stretchability of the electrical insulating base material in the same direction as the roll direction. A planar heating element provided with a protective layer. The planar heating element according to claim 1 or 2, wherein the protective layer that restricts the stretchability of the electrically insulating base material having flexibility is formed of long fibers arranged in a restricted stretch direction. The protective layer for restricting the stretchability of the electrically insulating base material having flexibility is formed by long fibers arranged in alignment in the restricting stretch direction, and the long fiber forming the protective layer is an electrically insulating base material. The planar heating element according to claim 3, wherein the planar heating element is formed so as to be entangled with the fibers forming the substrate and integrated with the electrically insulating base material.