JP2008300050A - Polymer heating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer heating element excellent in long-term reliability and long-term durability. <P>SOLUTION: The heating element is provided with a pair of electrodes 4, 4' pinched with a base-side base material 2 and a cover-side base material 3, a polymer resistive element 5 with PTC characteristics formed between the pair of electrodes 4, 4', and an adhesive layer 6 made of saturated copolymer polyester resin intercalated between the both base materials, the adhesive layer 6 is set at a melting point of 100°C to 150°C. Therefore, since a melting point of the resin used as the adhesive layer 6 lies within a range of 100°C to 150°C, the adhesive layer 6 can be formed in a uniform and stable thin-film shape on the base-side base material 2 or the cover-side base material 3 in a comparatively standard process such as a T-die extrusion method or an inflation method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer heating element using Joule heat of a polymer resistor, and more particularly to a polymer heating element that has long-term reliability and can be produced at low cost.

  2. Description of the Related Art Conventionally, as a heat generating portion of a planar heating element, a material obtained by dispersing a conductive material such as carbon black, metal powder, or graphite in a resin is known. In particular, when a PTC (Positive Temperature Coefficient) heating element that exhibits a self-temperature control function is used by combining a conductive material and a resin, there is an advantage that a temperature control circuit is not required and the number of parts can be reduced. Known as a device.

  Specifically, as shown in FIG. 4, an electrode 22 made of a conductive ink composition is printed on a base material 21 made of a ceramic or an insulating metal plate and having a function as a casing structure. Alternatively, the resistor 23 is formed by printing or coating the resistor ink composition at a position where power is supplied, and the electrode 22 and the resistor 23 are further covered with a cover material 24 to generate a heating element. 25.

  Since the electrode 22 and the resistor 23 are isolated from the outside by the base material 21 and the cover material 24, long-term reliability can be ensured.

  Various cases have been proposed in which an adhesive layer is additionally provided between the base material 21 and the cover material 24.

  Conventionally, examples of forming a polymer resistor by printing and using it as a heating element include automobile door mirrors, washstand mirrors, floor heating appliances and the like for dew / frost removal (for example, , See Patent Document 1).

  As an electrode material, a silver paste or a copper paste is often used as a conductive ink composition, and a thin film electrode is obtained by applying a solution diluted to a certain viscosity or concentration with a solvent and then drying. It is done.

  However, the process of creating the electrode part by coating or printing is a relatively initial stage of the polymer heating element process, although the paste material itself is relatively expensive, so subsequent resistor printing In addition, when a problem occurs in the process until the heating element is completed, all these printed electrodes are discarded.

  Further, the silver paste or copper paste remaining in the printing machine or coating machine cannot be sufficiently collected, and the amount of paste material used is increased as compared with the actually required printing area, resulting in an increase in loss cost.

  Furthermore, when applying to the sheet | seat which consists of a polymer heat generating body, additional measures, such as newly providing the metal terminal etc. which can endure a solder process etc. as an electrical connection part, are essential.

  As a means for solving some of these problems, a method of using a metal foil as an electrode material other than paste is naturally known (see, for example, Patent Documents 2, 3, and 4).

These relate to a planar heating device using an electrolytic copper foil, and are configured to use an electrolytic copper foil etched into a predetermined pattern. Since a copper foil is formed on an insulating base material and then a process such as pattern nigging and electrode creation is required, the electrode creation process becomes expensive.

  In addition to the above, examples using a tape-shaped metal foil are also known (see, for example, Patent Documents 5 and 6).

Further, it is generally known that when copper or a copper compound comes into contact with an olefin resin such as polyethylene or polypropylene in a high temperature atmosphere, they become a catalyst to promote thermal degradation of the resin (for example, non-patent) Reference 1).
JP 2002-371699 A JP-A-8-17557 Japanese Patent No. 3484927 JP 2001-185332 A Japanese Patent Publication No. 7-15830 Japanese Patent No. 3032839 R. Gaechter, H .; mueller: “Plastics Additives”, p104 (1984), Oxford University, New York

  The electrode 22 and the resistor 23 shown in FIG. 4 are isolated from the outside by the base material 21 and the cover material 24, but are not sufficient for the intrusion of oxygen and moisture from the end face only by overlapping, It is difficult to obtain long-term reliability.

  Various proposals have been made in which an adhesive layer is separately provided, but the conditions for the adhesive layer have not been specifically shown in which case a heating element excellent in long-term durability can be obtained.

  Further, the conventional method is characterized in that a conductive tape made of copper foil is used as an electrode, and a flat metal plating powder is used as a coating for a heating resistor. And is expensive.

  Further, generally, when copper or a copper compound comes into contact with an olefin resin such as polyethylene or polypropylene in a high temperature atmosphere, they become a catalyst to cause a thermal deterioration reaction of the resin, so-called “copper damage”.

  The present invention solves the above-mentioned problems of the prior art, and is excellent in productivity, manageability, long-term reliability, less loss in construction, and with the resistor part in contact with the metal electrode part. The purpose is to improve the contact.

  The polymer heating element of the present invention for solving the conventional problems has a pair of electrodes sandwiched between a base-side base material and a cover-side base material, and PTC characteristics formed between the pair of electrodes. A polymer resistor and an adhesive layer made of a saturated copolyester resin interposed between the two substrates are provided, and the adhesive layer has a melting point set to 100 ° C to 150 ° C.

Since the melting point of the resin used as the adhesive layer is in the range of 100 ° C. to 150 ° C., these adhesive layers are applied to the base side base material or the cover side base material by a relatively standard process such as a T-die extrusion method, A uniform and stable thin film can be formed using an inflation method or the like.

  The polymer heating element of the present invention can provide a highly reliable and cost-effective heater by limiting the type and melting point range of the resin serving as the adhesive layer, and can also provide a product with excellent mass productivity. Can be provided.

  In a first aspect of the present invention, a pair of electrodes sandwiched between a base-side base material and a cover-side base material, a polymer resistor having PTC characteristics formed between the pair of electrodes, and the two base materials And an adhesive layer made of a saturated copolyester resin interposed, and the adhesive layer has a melting point set to 100 ° C. to 150 ° C.

  Since the melting point of the resin used as the adhesive layer is in the range of 100 ° C. to 150 ° C., these adhesive layers are applied to the base side base material or the cover side base material by a relatively standard process such as a T-die extrusion method, A uniform and stable thin film can be formed using an inflation method or the like. In the case where the melting point is higher than 150 ° C., heat resistance is required for the base material as a base, which is expensive.

  When the melting point of the adhesive layer is in the range of 100 ° C. to 150 ° C., these adhesive layers are brought into contact with a heating device such as a predetermined roller held at a high temperature for a relatively short time using a normal laminating apparatus. Since it melts to a sufficient extent to develop an adhesive function, a good laminating process can be realized.

  The laminating process here means a step of heat-sealing at least a part of the electrode and the base side base material in which the resistor is prepared in advance by printing or the like and the cover side base material in which the adhesive layer is prepared in advance. Therefore, the electrode and the resistor are covered with the base material and the adhesive layer, and can be isolated from moisture and oxygen, so that long-term stability can be exhibited.

  When the melting point is higher than 150 ° C., it is preferable in terms of exhibiting long-term thermal stability. However, heat treatment at 200 ° C. or higher is required under lamination conditions and the like, and therefore higher temperature heat resistance is required for the base material used as a base. Will be required. When a base material having insufficient heat resistance is used, the base material exhibits shrinkage or expansion, which indirectly has an undesirable effect on the initial resistance value.

  When the melting point is lower than 100 ° C., a thin film layer can be easily obtained. However, when the temperature setting during storage is high, the occurrence of self-adhesion, oxidation degradation, moisture adsorption, and the like also occur.

  In addition, when the normal use of the heating element is assumed, it is often used at a sensory temperature of about 40-50 ° C., but the temperature of the heating element itself depends on its heat retaining state and heat insulation state, but is close to 80 ° C. In view of such points, it is more preferable that the melting point is a high temperature, and when it is lower than 100 ° C., sufficient heat resistance and strength characteristics are shown to ensure long-term reliability. I can't.

  By using a copolyester resin as the kind of the adhesive layer, it is possible to show good adhesiveness with polyethylene terephthalate which is often employed from the viewpoint of durability and insulation as a base material of a heating element.

  Accordingly, the construction method and management are not complicated, and long-term stability can be ensured for the resistor, and a good heating element can be obtained.

  The second invention is the first polymer heating element in which the thickness of the adhesive layer is set to 30 to 100 μm and has a layer having a sufficient thickness with respect to the thickness of the electrode or resistor to be bonded. Accordingly, these surfaces can be covered without the adhesive layer being divided in the middle, so that it is possible to provide a polymer heating element that is free from oxidative deterioration and moisture deterioration.

  The third invention is a saturated copolymer polyester resin in which the adhesive layer contains an antioxidant, particularly in any one of the first and second polymer heating elements, and the resin itself has an antioxidant function. As a result, even if a part of the base material of the heating element is peeled off, the anti-oxidation function of these adhesive layers can delay the progress of oxidative deterioration, and a highly reliable polymer heating element can be obtained. Can do.

  Further, even when the high temperature state continues for a long time and the gas permeability of the base material increases, the oxidation preventing function of the adhesive layer can prevent the oxidative deterioration of the resistor and the electrode.

  According to a fourth invention, in the polymer heating element of the first invention in particular, at least one of the base-side base material and the cover-side base material is polyethylene terephthalate, and a relatively versatile resin film is used as the base material. Therefore, a polymer heating element can be produced with a low cost and easy construction method.

  In a fifth aspect of the present invention, in the polymer heating element of the first aspect of the invention, the pair of electrodes include a main electrode and a plurality of branch electrodes led out from the main electrode toward the opposing main electrode. At least a part of the main electrode is formed of copper foil, and an electrode can be formed by a simple construction method, and a polymer heating element excellent in cost can be provided.

  When the electrode is formed by applying or printing a paste, it is essential to newly provide a metal terminal or the like that can withstand soldering as a process for the electrical connection part. Since it is possible to directly perform a soldering process or the like, it is not necessary to newly provide a metal terminal or the like, and it is possible to reduce the process required for that and the cost of the metal terminal.

  In addition, when covering with the cover side substrate on which the adhesive layer is formed on the surface side on which the branch electrode and the resistor are printed, the main electrode can be bonded at the same time. It is possible to make the electrode preparation process close to the last of all the processes, and it is possible to suppress the use of useless electrodes during mass production.

  The sixth aspect of the invention is a polymer heating element of the fifth aspect of the invention, in particular, the branch electrode is formed by printing using a silver paste, so that the polymer has excellent adhesion to the resistor and has good heat generation characteristics. A heating element can be provided.

  According to a seventh aspect of the invention, in the polymer heating element of the first aspect of the invention, at least one of the base-side base material, the cover-side base material, and the adhesive layer contains a copper damage inhibitor and is used at a high temperature for a long time. However, a highly reliable polymer heating element can be provided.

  In an eighth aspect of the invention, in the polymer heating element of the first aspect of the invention, at least one of the base-side base material and the cover-side base material is formed by laminating a fiber layer and a film layer made of a nonwoven fabric or a woven fabric. Thus, a polymer heating element excellent in flexibility and comfort can be 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)
In FIG. 1, the polymer heating element 1 includes a pair of electrodes 4, 4 ′ sandwiched between an electrically insulating base side substrate 2 and a cover side substrate 3, a polymer resistor 5, and an adhesive layer 6. Become.

  As the base-side substrate 2, a polyethylene terephthalate (PET) film having a thickness of 125 μm was used.

  The pair of electrodes 4 and 4 ′ which are electrically on the positive side and the negative side are formed by printing and drying a conductive paste on one side surface of the base-side substrate 2. As the conductive paste, a material obtained by dispersing silver powder as a conductivity-imparting material in a copolyester resin is used.

  The polymer resistor 5 has a positive resistance temperature characteristic, and a paste of an ethylene vinyl acetate copolymer and carbon black is printed and dried on the surface on which the electrodes 4 and 4 'are formed. Formed.

  The electrodes 4 and 4 'are arranged so as to face each other, and when power is supplied, current flows and heat is generated.

  The adhesive layer 6 is a T-die extrusion method on a cover side substrate 3, for example, a 75 μm thick PET film, so that a saturated copolymer polyester resin (GM-920, manufactured by Toyobo Co., Ltd.) having a melting point of 107 ° C. has a thickness of 30 μm. Heat-sealed and laminated with

  A laminate in which the adhesive layer 6 and the cover-side base material 3 were integrally formed was laminated so as to cover the electrodes 4, 4 ′ and the polymer resistor 5.

  The roll surface temperature of the laminate was set to 150 ° C. so that the thermal deformation of the base substrate 2 and the cover substrate 3 was extremely small so that the adhesive layer 6 was sufficiently melted and functioned as an adhesive layer.

  The polymer heating element 1 produced as described above has a structure sandwiched with PET films. In order to show the flexibility to follow these films, it is incorporated into a floor mat or the like as a heater for heating, and the feet are heated. It is attached to the outer surface or the inner surface of the seat portion such as the backrest portion, etc., and is used to warm the part of the human body that comes into direct contact.

  In order to develop more comfortable flexibility and adhesion, it is desirable that the polymer heating element 1 can change the heat generation area and the heat generation temperature according to the application, and it is necessary to design various heat generation patterns. However, the details are omitted here.

  A pair of electrodes 4, 4 ′ disposed so as to face each other are disposed so as to overlap the outside of the polymer heating element 1. When power is supplied through the electrodes 4 and 4 ′, current flows through the polymer resistor 5 to generate heat.

  The polymer resistor 5 has a PTC characteristic, and has a self-temperature adjusting function so that the resistance value increases as the temperature rises to reach a predetermined temperature.

  That is, the polymer resistor 5 gives the polymer heating element 1 a function that is highly safe and does not require temperature control.

  In addition, the polymer heating element 1 having PTC characteristics can exhibit fast heat performance and energy saving performance as compared with a conventional linear heater.

Wire heaters require a temperature controller. Temperature controller is on-off (ON-OFF)
The heat generation temperature is controlled by controlling energization. Since the heater wire temperature at the time of ON rises to about 80 ° C., it is necessary to arrange the heater wire at a certain distance from the surface of the heating element when coming into contact with a human body or the like.

  On the other hand, in the polymer heating element 1, since the heat generation temperature is self-controlled in the range of 40 ° C to 45 ° C, it can be placed close to the human body and the like. Therefore, energy saving can be realized.

  The length of the polymer resistor 5 between the electrodes 4 and 4 ′ was set to 100 mm. The obtained polymer heating element 1 had a sheet resistance value of 50Ω / □ and a surface temperature of 42 ° C. when DC 15 V was applied (outside temperature 20 ° C.).

  In order to confirm the effectiveness of the adhesive layer 6, the heat resistance at 80 ° C. was evaluated, and it was confirmed that the resistance value did not change up to 20,000 hours at 80 ° C., and that an accelerated test was performed at 80 ° C. or higher. After that, it was confirmed that the resistance value of the resistor gradually changed to the high resistance side, and it was revealed that the resistance value showed extremely long-term durability at the actual use level.

(Embodiment 2)
As the polymer heating element according to the second embodiment of the present invention, a polymer heating element having the same configuration as that of the first embodiment was prepared by the following method.

  As the base-side substrate 2, a 75 μm thick polyethylene terephthalate (PET) film was used.

  The pair of electrodes 4 and 4 ′ which are electrically on the positive side and the negative side are formed by printing and drying a conductive paste on one side surface of the base-side substrate 2. As the conductive paste, a material obtained by dispersing silver powder as a conductivity-imparting material in a copolyester resin is used.

  The polymer resistor 5 has a positive resistance temperature characteristic, and a paste of an ethylene vinyl acetate copolymer and carbon black is printed and dried on the surface on which the electrodes 4 and 4 'are formed. Is formed.

  The electrodes 4 and 4 'are a pair of wide main electrode portions so as to face each other, and a comb shape in which a plurality of branch electrodes are led out alternately from the main electrodes 4a and 4a' toward the other main electrode portion. When the polymer resistor 5 arranged so as to overlap the polymer resistor 5 is fed from a large number of branch electrodes, current flows and heat is generated.

The adhesive layer 6 was prepared by adding 0.1% of a phenolic antioxidant (Irganox 1010, manufactured by Ciba Specialty Chemicals Co., Ltd.) to 1 part by weight of a saturated copolyester resin having a melting point of 107 ° C. (GM-920, manufactured by Toyobo Co., Ltd.). In addition to being 03 parts by weight, the thickness of the kneaded product is 50 μm by heat fusion by a T-die extrusion method on a polybutylene terephthalate (PBT) film having a thickness of 50 μm to be the cover side substrate 3. Laminated.

  A laminate in which the adhesive layer 6 and the cover-side substrate 3 were integrally formed was laminated so that the adhesive layer side covered the electrodes 4, 4 ′ and the polymer resistor 5.

  Note that the roll surface temperature of the laminate was 160 ° C., and the thermal deformation of the base-side base material 2 and the cover-side base material 3 was extremely small, and the adhesive layer 6 was sufficiently melted so that the adhesive function was sufficiently exhibited.

  The polymer heating element 1 prepared as described above has a structure sandwiched with PET films, and is incorporated in a floor mat or the like as a heater for heating in order to show the flexibility to follow these films. It is used to warm the parts of the human body that are attached to the outer surface or the inner surface of the seat portion such as the seat back portion or the backrest portion.

  In order to develop more comfortable flexibility and adhesion, it is desirable that the polymer heating element 1 can change the heat generation area and the heat generation temperature according to the application, and it is necessary to design various heat generation patterns. However, the details are omitted here.

  By supplying power from a pair of electrodes 4 and 4 ′ arranged so as to face each other, current flows through the polymer resistor 5 to generate heat.

  The polymer resistor 5 has a PTC characteristic, and has a self-temperature adjusting function so that the resistance value increases as the temperature rises to reach a predetermined temperature.

  That is, the polymer resistor 5 gives the polymer heating element 1 a function that is highly safe and does not require temperature control.

  In addition, the polymer heating element 1 having PTC characteristics can exhibit fast heat performance and energy saving performance as compared with a conventional linear heater. Wire heaters require a temperature controller. The temperature controller controls the heat generation temperature by controlling energization by on-off control. Since the heater wire temperature at the time of ON rises to about 80 ° C., it is necessary to arrange the heater wire at a certain distance from the surface of the heating element when coming into contact with a human body or the like.

  In contrast, in the polymer heating element 1, the heat generation temperature is self-controlled within the range of 40 ° C to 45 ° C. Therefore, it can arrange | position close to a human body etc. Therefore, the rapid heat property and the heat radiation loss to the outside can be reduced, and thus energy saving can be realized.

  The length of the polymer resistor 5 between the electrodes 4 and 4 ′ was set to 100 mm, and the polymer heating element 1 was obtained. The obtained polymer heating element had a sheet resistance of 55Ω and a surface temperature of 42 ° C. when DC 15V was applied (outside temperature 20 ° C.).

  When the heat resistance at 80 ° C. was evaluated to confirm the effectiveness of the adhesive layer 6, it was confirmed that the resistance value did not change until 18,000 hours at 80 ° C., and that an accelerated test was performed at 80 ° C. or higher. Then, it was confirmed that the resistance value of the polymer resistor 5 gradually changed to the high resistance side, and it was revealed that the resistance value of the polymer resistor 5 showed extremely long-term durability at the actual use level.

(Embodiment 3)
FIG. 2 shows Embodiment 3 of the present invention, in which the polymer heating element 11 includes a pair of electrodes 14 and 14 ′ sandwiched between an electrically insulating base-side base material 12 and a cover-side base material 13, and It consists of a polymer resistor 15 and an adhesive layer 16.

  The electrodes 14 and 14 'are configured by providing branch electrodes 17a and 17a' alternately from the corresponding main electrodes 14a and 14a '.

  As the base-side substrate 12, a polyethylene terephthalate (PET) film having a thickness of 125 μm was used.

First, branch electrodes 17a and 17a ′ were formed on the PET film as described below. Using a conductive paste in which silver powder is dispersed as a conductivity-imparting material in a copolyester resin,
The branch electrodes 17a and 17a ′ are configured at predetermined intervals according to the design by printing and drying.

  The branch electrodes 17a and 17a ′ are arranged so that power can be supplied from every other main electrode 14a and 14a ′, and the state at the stage where only the branch electrodes 17a and 17a ′ are printed is shown in FIG. .

  FIG. 3 shows a state where only the branch electrodes 17a and 17a 'are printed, and the positions of the main electrodes 14a and 14a' arranged later are also shown by broken lines.

  As the structure of these electrodes 14 and 14 ', a pair of wide main electrodes 14a and 14a' so as to face each other, and a plurality of branch electrodes alternately from the main electrode portions 14a and 14a 'toward the other side. 17a and 17a ′ are derived from a comb shape.

  Thereafter, the polymer resistor 15 was formed by printing and drying so as to cover most of the dried branch electrodes 17a and 17a '.

  The polymer resistor 5 has a positive resistance temperature characteristic and is a paste obtained by kneading an ethylene vinyl acetate copolymer and carbon black.

  As the adhesive layer 16, a T-die extrusion method is performed on a PET film having a thickness of 50 μm, which becomes the cover-side base material 13, so that a saturated copolymer polyester resin having a melting point of 145 ° C. (GM-440, manufactured by Toyobo Co., Ltd.) has a thickness of 75 μm. And laminated by heat fusion.

  At this time, as the main electrodes 14a and 14a ′, the adhesive layer 16 and the adhesive layer 16 are bonded to a predetermined position of the base-side substrate 12 with the adhesive side of the conductive tape made of a copper foil whose surface is tin-plated. The cover-side base material 13 was integrally molded and laminated so that the adhesive layer side covered the electrodes 14, 14 ′ and the polymer resistor 15.

  The roll surface temperature of the laminate was 180 ° C., the thermal deformation of the base substrate 12 and the cover substrate 13 was small, and the adhesive layer 16 was sufficiently melted to function as an adhesive layer.

  The polymer heating element 11 was obtained by setting the distance between the main electrodes 14a and 14a 'to 150 mm and the interval between the branch electrodes 17a and 17a' to be 10 mm.

  The resulting polymer heating element 11 had a surface temperature of 42 ° C. when a direct current of 13.5 V was applied (outside air temperature 20 ° C.). The conductive tape made of copper foil used as the electrode showed good adhesion with the silver paste previously printed, and it was confirmed that the heat generation characteristics were not much different from the case of using the silver paste.

  Moreover, in order to confirm the effectiveness of the adhesive layer, when the heat resistance at 80 ° C. was evaluated, the resistance value did not change until 22,000 hours at 80 ° C., and the acceleration test was performed at 80 ° C. or higher. After that, it was confirmed that the resistance value of the resistor gradually changed to the high resistance side, and it was revealed that the resistance value showed extremely long-term durability at the actual use level.

(Embodiment 4)
A polymer heating element according to the fourth embodiment of the present invention having the same configuration as that of the third embodiment was prepared by the following method.

The adhesive layer 16 has a phenolic antioxidant (Irganox 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.) in an amount of 0.1 part by weight with respect to 1 part by weight of a saturated copolyester resin having a melting point of 145 ° C. (GM-440 manufactured by Toyobo Co., Ltd.). In addition to being 03 parts by weight, the kneaded material is laminated by thermal fusion by a T-die extrusion method on a 50 μm thick PET film to be the cover side substrate 13 so that the thickness of the kneaded product becomes 50 μm. . Other materials, configurations, and construction methods were the same as those in the third embodiment.

  The polymer heating element 11 was obtained by setting the distance between the main electrodes 14a and 14a 'to 150 mm and the interval between the branch electrodes 17a and 17a' to be 10 mm. The resulting polymer heating element had a surface temperature of 42 ° C. when a direct current of 13.5 V was applied (outside air temperature 20 ° C.).

  The conductive tape made of copper foil used as the electrode showed good adhesion with the silver paste previously printed, and it was confirmed that the heat generation characteristics were not much different from the case of using the silver paste.

  Moreover, in order to confirm the effectiveness of the adhesive layer, when the heat resistance at 80 ° C. was evaluated, the resistance value did not change until 25,000 hours at 80 ° C., and the acceleration test at 80 ° C. or higher was conducted. After that, it was confirmed that the resistance value of the resistor gradually changed to the high resistance side, and it was revealed that the resistance value showed extremely long-term durability at the actual use level.

(Embodiment 5)
As the polymer heating element in the fifth embodiment of the present invention, a polymer heating element having the same configuration as in the third embodiment was prepared by the method as described below.

  Adhesive layer 16 is a phenolic antioxidant (Irganox 1010, manufactured by Ciba Specialty Chemicals Co., Ltd.) with respect to 1 part by weight of saturated copolyester resin having a melting point of 107 ° C. (GM-920, manufactured by Toyobo Co., Ltd.). 03 parts by weight and copper damage inhibitor (CDA-6) are added so as to be 0.05 parts by weight, and on the PET film having a thickness of 50 μm that becomes the cover-side base material 13 so that the thickness of the kneaded material becomes 50 μm. And laminated by heat fusion by a T-die extrusion method.

  The material, configuration, and construction method were the same as those in Embodiment 3 except that the roll surface temperature of the laminate was 170 ° C.

  The polymer heating element 11 was obtained by setting the distance between the main electrodes 14a and 14a 'to 150 mm and the interval between the branch electrodes 17a and 17a' to be 10 mm. The resulting polymer heating element had a surface temperature of 42 ° C. when a direct current of 13.5 V was applied (outside air temperature 20 ° C.).

  The conductive tape made of copper foil used as the electrode showed good adhesion with the silver paste previously printed, and it was confirmed that the heat generation characteristics were not much different from the case of using the silver paste.

  Moreover, in order to confirm the effectiveness of the adhesive layer, when the heat resistance at 80 ° C. was evaluated, it was confirmed that the resistance value did not change at 80 ° C. until 20,000 hours, and that an accelerated test was performed at 80 ° C. or higher. After that, it was confirmed that the resistance value of the resistor gradually changed to the high resistance side, and it was revealed that the resistance value showed extremely long-term durability at the actual use level.

(Embodiment 6)
As a polymer heating element in Embodiment 6 of the present invention, a polymer heating element having the same configuration as in Embodiment 3 was prepared by the following method.

  As the base-side base material 12, an olefin-based thermoplastic elastomer having a melting point of 180 ° C. formed on a non-woven fabric in which polyethylene terephthalate fibers are entangled on a film having a thickness of 50 μm was used.

  First, the main electrode 14a, 14a ′ and the branch electrodes 17a, 17a ′ are used on the film surface side of the base-side substrate 12, and a conductive paste in which silver powder is dispersed as a conductivity-imparting material in a copolyester resin is used. And obtained by printing and drying.

  The structure of these electrodes 14 and 14 'includes a pair of wide main electrodes 14a and 14a' so as to face each other, and a plurality of branch electrodes 17a alternately from the main electrodes 14a and 14a 'toward the other side. , 17a ′ is derived from a comb-like shape, and the polymer resistor 15 is disposed so as to overlap with the comb shape. When power is supplied from a large number of branch electrodes 17a, 17a ', a current flows through the polymer resistor 15 to generate heat.

  Thereafter, the polymer resistor 15 was obtained by printing and drying so as to cover most of the dried branch electrodes 17a and 17a '.

  The polymer resistor 15 has a positive resistance temperature characteristic and is a paste obtained by kneading an ethylene vinyl acetate copolymer and carbon black.

  The adhesive layer 16 is made of T on a non-woven fabric in which a polyethylene terephthalate fiber serving as the cover-side base material 13 is entangled with a saturated copolymer polyester resin having a melting point of 107 ° C. (GM-920, manufactured by Toyobo Co., Ltd.) to a thickness of 50 μm. The laminate was formed by heat fusion using a die extrusion method.

  A laminate in which the adhesive layer 16 and the cover-side base material 13 were integrally formed was laminated so that the adhesive layer side covered the electrodes 14, 14 ′ and the polymer resistor 15.

  The roll surface temperature of the laminate was 150 ° C., the thermal deformation of the non-woven fabric of the base side substrate 12 and the cover side substrate 13 was small, and the adhesive layer 16 was sufficiently melted so that the bonding function was exhibited.

  The polymer heating element 11 was obtained by setting the distance between the main electrodes 14a and 14a 'to 150 mm and the interval between the branch electrodes 17a and 17a' to be 10 mm.

  The resulting polymer heating element had a surface temperature of 42 ° C. when a direct current of 13.5 V was applied (outside air temperature 20 ° C.).

  Moreover, when the heat resistance at 80 ° C. was evaluated to confirm the effectiveness of the adhesive layer 16, it was confirmed that the resistance value did not change until 15,000 hours at 80 ° C., and an accelerated test was performed at 80 ° C. or higher. As a result, it was confirmed that the resistance value of the resistor gradually changed toward the high resistance side, and it was revealed that the resistance value exhibited extremely long-term durability at the actual use level.

  As described above, the heating element according to the present invention is made of a polyester resin in which a polymer resistor made of a polymer and conductive carbon and an electrode are sandwiched between a base substrate and a cover substrate and the melting point range is limited. By using the adhesive layer, a reliable heating element can be provided at low cost, and a product with excellent mass productivity can be provided.

(A) is a top view which shows the structure of the polymer heating element in this Embodiment 1, (b) is XY sectional drawing of (a). (A) is a notch top view which shows the structure of the heat generating body in this Embodiment 2, (b) is XY sectional drawing of (a). Cutaway plan view showing the configuration of the heating element in the second embodiment (A) is a top view which shows the conventional heat generating body, (b) is XY sectional drawing of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Polymer heating element 2,12 Base side base material 3,13 Cover side base material 4,4 ', 14,14' Electrode 4a, 4a ', 14a, Main electrode 5,15 Polymer resistor 6,16 Adhesive layer 17a, 17a 'Branch electrode

Claims (8)

A pair of electrodes sandwiched between a base-side base material and a cover-side base material, a polymer resistor having PTC characteristics formed between the pair of electrodes, and a saturated copolymer interposed between the two base materials A polymer heating element having a melting point set to 100 ° C. to 150 ° C. The polymer heating element according to claim 1, wherein the thickness of the adhesive layer is set to 30 to 100 μm. The polymer heating element according to claim 1 or 2, wherein the adhesive layer is a saturated copolymerized polyester resin containing an antioxidant. The polymer heating element according to claim 1, wherein at least one of the base-side base material and the cover-side base material is polyethylene terephthalate. The pair of electrodes has a main electrode and a plurality of branch electrodes led out from the main electrode toward the opposing main electrode, and at least a part of the main electrode is formed of copper foil. Polymer heating element. The polymer heating element according to claim 5, wherein the branch electrode is formed by printing using a silver paste. The polymer heating element according to claim 1, wherein at least one of the base-side base material, the cover-side base material, and the adhesive layer contains a copper damage inhibitor. The polymer heating element according to claim 1, wherein at least one of the base-side base material and the cover-side base material is configured by laminating a fiber layer and a film layer made of a nonwoven fabric or a woven fabric.