JP2010129425A - Resistive element composition and heating element using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve improvement in flexibility and reliability of a resistive element composition used for a planar heating element. <P>SOLUTION: With the use of, for instance, mesh-like span-lace nonwoven fabric having a basis weight of 50 g/m<SP>2</SP>and made of flame-resistant polyester fiber as a flexible flame-resistant base material 2, and with an electrode 3 on the flexible flame-resistant base material 2, a pair of tin-plated twisted copper wires with a resistance value of 0.03 Ω/cm or less are partially seamed with threads. On the flexible flame-resistant base material 2 with the pair of electrodes 3 arranged, a film 4 of the resistive element composition 4 is formed by calendering, and the resistive element composition 4 is thermally fused onto the electrodes 3 and the flexible flame-resistant base material 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resistor composition having flexibility that can be attached to a device having an arbitrary surface shape, and having high reliability and PTC characteristics, and a heating element using the resistor composition.

  Conventionally, a heat generating part of this type of sheet heating element has a base polymer and a conductive material such as carbon black, metal powder, and graphite dispersed in a solvent as a resistor ink, which is then printed and dried on a substrate. Thus, a resistor composition that generates heat when energized is used. In particular, many base polymers have a PTC characteristic using a crystalline resin.

  Specifically, as shown in FIGS. 7 and 8, the sheet heating element is a pair obtained by printing and drying a conductive paste such as a silver paste on an electrically insulating base material 50 such as a polyester film. Comb-shaped electrodes 51 and 52, and a polymer resistor 53 which is disposed at a position where power is supplied by the comb-shaped electrodes 51 and 52 which is obtained by printing and drying polymer resistor ink.

  Further, the comb-shaped electrodes 51 and 52 and the polymer resistor 53 are covered and protected with a covering material 54 similar to that of the base material 50.

  As shown in FIG. 9, when a polyester film is used as the base material 50 and the covering material 54, for example, a modified polyethylene-based heat-fusible resin 55 is bonded in advance to the covering material 54, and heat is applied while applying heat. The base material 50 and the covering material 54 are bonded via the heat-fusible resin 55 by pressing (pressing when heated).

  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.

  A laminator 58 composed of two heating rolls 56 and 57 is generally used as the above-described hot pressurization means (see, for example, Patent Documents 1, 2, and 3).

  The PTC characteristic means a resistance temperature characteristic (Positive Temperature Coefficient) in which the resistance value increases as the temperature rises, and when the temperature reaches a certain temperature, the polymer resistor 53 having this PTC characteristic is meant. Can provide a planar heating element having a self-temperature adjusting function.

In addition, the resistor composition was not formed as an ink, but was formed by extruding a kneaded material prepared by kneading a conductive material such as carbon black or graphite with an electrode cable using a crystalline resin as a base polymer. There are also things. These are used as anti-freezing heaters.
Japanese Patent Laid-Open No. 56-13689 JP-A-6-96843 JP-A-8-120182

However, in the conventional configuration, the comb-shaped electrodes 51 and 52 and the polymer resistor 53 printed on the rigid electrically insulating base material 50 such as a polyester film and the like are protected by the same electrically insulating coating material 54. The structure lacks flexibility depending on the material and thickness of the base material 50 and the covering material 54, and when this planar heating element is used, for example, as a heater for a heating device of an automobile seat device, the seating feeling is low. In addition, when used in a handle heater, there is a problem that the feeling of touch is impaired.

  In the case where the resistor composition is prepared as an ink, the heating portion can be formed in a thin film of about several tens of micrometers by adjusting the coating amount, so that it is easy to exhibit the flexibility of the resistor composition itself.

  However, it is necessary to use an electrically insulating base material such as a polyester film having a smooth and non-impregnated surface as a surface on which the ink-like resistor composition is applied, which impairs flexibility. It was a result.

  In addition, it is necessary to use a large amount of expensive conductive paste as a comb-shaped electrode as a heating element, and it has a disadvantage that the cost is high because of a complicated multilayer structure.

  On the other hand, the resistor composition used for extrusion molding is thicker in millimeters than the one used for the ink, lacks flexibility, and has a configuration in which the electrode cables are close to each other, so it could not be said to be a planar heating element. .

  There are thin-wall molding methods such as T-die extrusion and calendaring, but no resistor composition suitable for these processing methods has been proposed.

  In view of the problems of the above-described conventional techniques, the problem to be solved by the present invention is to provide a resistor composition that can be molded thinly without using ink, and to provide flexibility and surface shape when mounted on a device. The purpose is to improve the feeling of use and reliability of the heating element and to reduce the cost.

  In order to solve the above problems, the resistor composition of the present invention comprises at least a crystalline resin composition, two or more different kinds of conductors, a flame retardant, a coupling agent, and an organic peroxide. Is.

  With this configuration, high reliability can be imparted by flame retardancy, strengthening of the bond between the conductor and the crystalline resin composition by the coupling agent, and improving heat resistance by crosslinking of the crystalline resin composition by the organic oxide. .

  According to the resistor composition of the present invention, it is possible to reduce the cost as well as to improve flexibility and usability and reliability when mounted on an instrument, as a thin-wall moldable one.

  The resistor composition of the present invention comprises at least a crystalline resin composition, two or more different kinds of conductors, a flame retardant, a coupling agent, and an organic peroxide.

  Therefore, high reliability can be imparted by flame retardancy, strengthening the bond between the conductor and the crystalline resin composition by the coupling agent, and improving heat resistance by crosslinking the crystalline resin composition by the organic oxide.

  Moreover, the kneaded material which consists of a crystalline resin composition, a conductor, a flame retardant, and a coupling agent is crosslinked with an organic oxide.

  With this configuration, the coupling agent and the organic oxide can be caused to act stepwise, whereby the effective action of the coupling agent and the organic oxide can be derived.

  Further, as the crystalline resin composition, a crystalline resin having different melting points and a low molecular weight crystalline composition are used in combination.

  This structure combines a crystalline resin that meets the design heat generation temperature with a crystalline resin with higher heat resistance (melting point) to improve heat resistance, or by using a low molecular weight crystalline composition, a steep specific volume High PTC characteristics can be realized due to changes in

  As crystalline resins, ethylene / vinyl acetate copolymer, ethylene / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer It is used either or in combination.

  With this configuration, it is possible to provide a resistor composition having PTC characteristics having a saturation heat generation temperature of about 100 ° C. or less.

  Further, as the low molecular weight crystalline composition, either a wax or a surfactant or a combination thereof is used.

  With this configuration, it is possible to provide a resistor composition that has a sharper change in specific volume than the crystalline resin and has high PTC characteristics, and it is possible to stabilize the dispersion of the conductor and improve the affinity with the crystalline resin.

  Further, as a conductor, carbon black having a different primary particle shape and graphite are used in combination.

  With this configuration, it is possible to provide a resistor composition having a low resistance value and a high PTC characteristic.

  Further, as the graphite, spherical graphite having a particle size of at least 5 to 20 microns is used.

  With this configuration, it is possible to provide a resistor composition having high PTC characteristics and high thermal conductivity.

  Further, the flame retardant is liquid at ordinary temperature or melts at a temperature below the kneading temperature to become liquid, and phosphorus, nitrogen, and silicone are used alone or in combination.

  With this configuration, the flame retardancy is exhibited and the PTC characteristics are compensated.

  In addition, the heating element of the present invention includes at least a flexible flame retardant base material, at least a pair of electrodes disposed on the flexible flame retardant base material, and the pair of electrodes electrically connected to generate heat. A film-like resistor composition, a film-like flame-retardant hot melt material, and a protective film.

  With this configuration, a heating element having flexibility, flame retardancy, and high reliability can be provided.

  Moreover, a mesh-shaped nonwoven fabric is used as a flexible flame-retardant base material. With this configuration, it is possible to provide a heating element that is flexible and highly flame-retardant.

  The flame-retardant hot melt material is made of a crystalline polyester resin that is hardly soluble in organic solvents and a nitrogen / phosphorous powder flame retardant.

  With this configuration, it is possible to provide a highly reliable heating element that is flame retardant and has high resistance when dying.

  And this heat generating body is used for the heat source for heating of the seat apparatus for motor vehicles.

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

(Embodiment 1)
1 and 2, the planar heating element 1 is made of a flexible flame retardant base material 2 using, for example, a 50 g / m 2 mesh mesh spunlace nonwoven fabric made of flame retardant polyester fiber. A pair of tin-plated stranded copper wires having a resistance value of 0.03 Ω / cm or less is sewed on the flame-retardant base material 2 as a pair, and is partially sewn with a thread.

  And the film 4 of the resistor composition 4 is created by calendering on the flexible flame-retardant substrate 2 on which the pair of electrodes 3 are arranged, and the resistor composition is applied to the electrode 3 and the flexible flame-retardant substrate 2. Object 4 was heat-sealed.

  Furthermore, as flame retardant hot melt material 5, 75 parts of crystalline polyester resin (trade name “Byron GM920”, manufactured by Toyobo Co., Ltd.) and powder flame retardant (trade name “ADK STAB FP-2100J”, Asahi Denka Kogyo ( (Made by Co., Ltd.) 25 parts, and formed as a protective film 6 with a thickness of 50 μm as a protective film 6 by T-die extrusion, and heat-sealed to the resistor composition 4.

  In the present embodiment, the planar heating element 1 is formed by punching out the central portion.

  Note that lead wires for supplying power to the pair of electrodes 3 are omitted. Further, the punching of the central portion is not limited to this place, and it is necessary to provide it at other places depending on the form of the skin material of the seat.

  In this case, it is necessary to change the wiring pattern of the electrode 3, but it is needless to say that this can be dealt with.

  Resistor composition 4 comprises, as a crystalline resin, 70 parts of ethylene / methyl acrylate copolymer (trade name “CG4002”, melting point 59 ° C., manufactured by Sumitomo Chemical Co., Ltd.), ethylene / methyl methacrylate copolymer It was composed of 30 parts of coalescence (trade name “ACRIFTH WH206”, melting point 86 ° C., manufactured by Sumitomo Chemical Co., Ltd.).

  35% by weight of the crystalline resin, 11% by weight of carbon black (trade name “Printex L”, primary particle diameter 21 nm, manufactured by Gusa) as two or more kinds of conductors, and carbon black (trade name “#” 10B ", primary particle diameter 79 nm, manufactured by Mitsubishi Chemical Corporation 22% by weight, graphite (trade name" CGB-15 ", spherical graphite, manufactured by Nippon Graphite Co., Ltd.) 22% by weight, flame retardant (product) Name: “Reophos RDP”, phosphate ester liquid flame retardant, manufactured by Ajinomoto Co., Inc., 13% by weight, wax, sorbitan stearate, resin modifier (trade name “Metabrene A-3000”, acrylic modified PTFE) Become.

  As shown in FIGS. 3 and 4, the planar heating element 1 is used as a heat source for seat heating by being attached to a seat portion 7 and a backrest portion 8 of an apparatus in an automobile seat.

  In order to correspond to the suspending portion (not shown) of the seat portion 7 and the backrest portion 8, an ear portion (an extension portion of the electrically insulating base material) for suspending in the central portion or the peripheral portion is provided. It is omitted here.

  In addition, the seat 7 and the backrest 8 to which the planar heating element 1 is mounted are generally deformed when a load is applied by a human body seated on the seat, and restored when the load is no longer applied. Therefore, the thin sheet heating element 1 mounted on the seat base 9 of the seat 7 and the backrest 8 is also provided with the seat 7 and the backrest 8 described above. A similar deformation must be made corresponding to the deformation.

  For this purpose, it is needless to say that various heat generation pattern designs and the arrangement shapes of the electrodes 3 therefor need to be changed, but they are omitted here.

  The electrode 3 has a pair of wide (electrically positive side and negative side) main electrodes 3a and 3b arranged so as to face each other along the outer side in the longitudinal direction of the planar heating element 1, and overlaps with this. By supplying power from the main electrodes 3a and 3b to the resistor composition 4 arranged as described above, a current flows through the resistor composition 4 to generate heat.

  In the above embodiment, the resistor composition 4 has PTC characteristics, and when the temperature rises, the resistance value rises, and has a self-temperature adjusting function so as to reach a predetermined temperature, and temperature control is unnecessary. It has a function as the highly safe planar heating element 1.

  Moreover, as what is built in the seat apparatus for motor vehicles, a seating feeling and a flame retardance can be satisfied.

  The seating feeling can be satisfied by the fact that there is no squeaking like paper and an elongation characteristic equivalent to that of the seat skin material, that is, a load of 7 kgf or less for 5% elongation.

  Further, as a planar heating element having PTC characteristics, quick heat and energy saving can be exhibited as compared with a conventional heating element using a tubing heater.

  A tube heater that uses a heating element requires a temperature controller and 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 dispose it at a certain distance from the seat skin material. On the other hand, in the planar heating element of this embodiment, the heating temperature is high. Since it is self-controlled within the range of 40 ° C. to 50 ° C., it can be arranged close to the vicinity of the seat skin material.

  Since the heat generation temperature is low and it is in the vicinity of the seat, it is possible to realize energy saving by being able to reduce heat loss and heat dissipation loss to the outside.

  Moreover, a flame retardance is realizable by mix | blending a flame retardant with the resistor composition 4 using a flame retardant nonwoven fabric for the flexible flame retardant base material 2.

  Flame retardancy is the automotive interior material flame retardant standard FMVSS302 (single fire extinguishing as well as nonflammability due to horizontal ignition, or if the burning rate between marked lines is 80 mm / min or less It was confirmed that it can be met if the amount of the flame retardant is at least 10% by weight.

  The sheet heating element 1 obtained in the present embodiment was subjected to an 80 ° C. oven standing test, a 150 ° C. oven standing test, and a −20 ° C. and 50 ° C. heat cycle test.

  As a result, the resistance value change rate was within 30% of the initial value after 500 hours, 200 hours and 200 times, respectively.

  It is thought that this factor is due to the strengthening of bonding between the conductor, particularly carbon black, and the resin due to the coupling agent, and the improvement in heat resistance due to the construction of a crosslinked structure between the resins due to the organic oxide.

  In order to exhibit excellent PTC characteristics, the present invention applies a combination of a plurality of conductors and a sea-island configuration.

  The details of the mechanism are currently unknown, but are presumed as follows.

  First, in order to obtain a resistor composition having PTC characteristics, it is necessary to select a crystalline resin to be used whose melting point is in the vicinity of the exothermic saturation temperature.

  The conductor is required to achieve a predetermined resistance value with the smallest possible addition amount, but such a conductor is generally called conductive carbon black, and has a primary particle diameter of about 20 nm or less and a structure. (It is an aggregate of primary particles such as a bunch of coral, which is correlated with oil absorption.) On the other hand, such conductive carbon black exhibits PTC characteristics. It had the disadvantage of being difficult to do.

  This is because the structure of conductive carbon black is developed, and the conductive path of the structure is not easily cut even by the change in specific volume due to the temperature of the crystalline resin (which is said to be the main cause of the PTC characteristics). It is said.

  On the other hand, the inventors have obtained as knowledge that carbon black having a large primary particle diameter has excellent PTC characteristics.

  Furthermore, a conductor such as graphite has a larger particle diameter than carbon black, and can be expected to have a contact function. By combining these conductors, the thickness is about 100 microns or less, and the sheet resistance is low. It has a resistance of 400Ω □ or less and a volume resistance of 4Ω · cm or less, and the ratio of the resistance value of 50 ° C. to the resistance value of 20 ° C., which is one index of PTC characteristics, is 1.5 or more and the resistance value of 20 ° C. It was possible to obtain a resistor composition in which the ratio of the resistance value at 80 ° C. to 5 was 5 or more.

  Although the details of the mechanism that was able to demonstrate excellent PTC characteristics while being low resistance are unknown, the formation of a new conductive path by combining a crystalline resin and a plurality of conductors, and the flame retardant made liquid This is considered to be due to the fact that the large thermal expansion coefficient of the liquid could be used.

  In the above embodiment, a crystalline resin is mainly used as the resistor composition. However, in order to further impart flexibility, a thermoplastic elastomer or an alkyl methacrylate / alkyl acrylate copolymer and 4 Needless to say, a processing aid made of a mixture with a fluorinated ethylene copolymer, a wax such as a saponified ester of a montanic acid part, or a plasticizer or dispersant such as another wax may be used as necessary. .

  Moreover, although it did not mention in particular as a shape of a conductor, you may combine with a whisker or a fiber-shaped thing other than spherical shape and an indefinite shape.

  Furthermore, although the tin plating copper wire was used as the electrode 3, it is not limited to this. A copper / silver alloy wire can also be used.

(Embodiment 2)
5 and 6 show a second embodiment of the present invention.

  5 and 6 are different from FIGS. 1 and 2 in that the resistor composition 4 is first heat laminated in a film shape by calendering on the flexible flame retardant substrate 2 and then the electrode 3 is provided by sewing. is there.

  In addition, about the structure which performs the same effect as FIG.1, 2, the same code | symbol is attached | subjected for convenience, and the thing of Embodiment 1 is used for concrete description.

  In order to make the electrical connection between the electrode 3 and the resistor composition 4 more reliable, the electrode 3 is previously coated with another resistor composition (covered resistor composition 11) (by extrusion molding around the electrode 3). The coated electrode 12 produced by manufacturing) is provided on the resistor composition 4 by sewing, and then subjected to pressure treatment during heating to connect the electrode 3 and the resistor composition 4 with the coated resistor composition. 11 to secure.

  Also in this configuration, the planar heating element 1 can be provided as a heating heat source of the automobile seat device, as in the first embodiment.

  In the first embodiment, the position of the electrode 3 is between the electrically insulating substrate 2 and the polymer resistor 4, whereas in the present embodiment, it is on the resistor composition 4. Since it is easy to confirm the positions of the electrode 3 and the covered electrode 12, the step of removing for increasing flexibility or attaching can be reliably performed.

  In addition, since there is a degree of freedom in the arrangement of the electrodes 3 in the subsequent process, the bonding process of bonding the resistor composition 4 to the electrically insulating substrate 2 is made common, and the planar heating element 1 having various heating patterns is designed. Has the advantage that can be done.

  The covering resistor composition 11 does not necessarily have PTC characteristics. Moreover, since the covering resistor composition 11 is formed in a thin film rather than the resistor composition 4 which has a heat generating function, it cannot be overemphasized that the volume resistance may be higher than the resistor composition which has a heat generating function.

  Moreover, in this Embodiment, although the case where the covering electrode 12 was fixed by sewing was performed, it is not limited to this.

  Needless to say, the covering resistor 12 may be fixed on the resistor composition 4 by thermal fusion with the covering resistor composition.

  As described above, the resistor composition according to the present invention is highly flexible and highly reliable, and can be used as a heating element for heating a vehicle seat, steering wheel, and other parts.

The top view which shows the planar heating element using the resistor composition in Embodiment 1 of this invention XY sectional view of FIG. Side view of the automobile seat apparatus to which the planar heating element is attached in the first embodiment Front view of the car seat device The top view which shows the planar heating element using the resistor composition in Embodiment 2 of this invention (A) is XY sectional drawing of FIG. 5, (b) is an expanded sectional view of the principal part of (a). Plan view showing a conventional planar heating element XY sectional view of FIG. Schematic configuration diagram at the time of bonding of the covering material of the heating element

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar heating element 2 Flexible flame-retardant base material 3 Electrode 3 Electrode 4 Resistor composition 5 Flame-retardant hot-melt material 6 Protective film 11 Covering resistor composition 12 Covered electrode

Claims (12)

A resistor composition comprising at least a crystalline resin composition, two or more different conductors, a flame retardant, a coupling agent, and an organic peroxide. The resistor composition according to claim 1, wherein a kneaded material comprising a crystalline resin composition, a conductor, a flame retardant, and a coupling agent is crosslinked with an organic oxide. The resistor composition according to claim 1 or 2, wherein a crystalline resin having different melting points and a low molecular weight crystalline composition are used in combination as the crystalline resin composition. As crystalline resin, any of ethylene / vinyl acetate copolymer, ethylene / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer The resistor composition according to claim 3, wherein the resistor composition is used in combination. The resistor composition according to claim 3, wherein the low molecular weight composition is a wax, a surfactant, or a combination thereof. The resistor composition according to claim 1 or 2, wherein the conductor is a combination of carbon black having different primary particle shapes and graphite. The resistor composition according to claim 6, wherein spherical graphite having a particle diameter of 5 to 20 μm is used as the graphite. 3. The resistor according to claim 1 or 2, wherein the flame retardant is liquid at ordinary temperature or melted at a temperature below the kneading temperature to be liquid, and the phosphor, nitrogen, or silicone is used alone or in combination. Composition. The resistor composition in a film form according to any one of claims 1 to 8, wherein the resistor composition is electrically connected to at least a pair of electrodes disposed on a flexible flame-retardant substrate. A heating element that is covered with a film-like flame-retardant hot melt material and a protective film. The heating element according to claim 9, wherein a mesh-like nonwoven fabric is used as the flexible flame-retardant substrate. The heating element according to claim 9, wherein the flame retardant hot melt material has crystallinity and comprises an organic solvent poorly soluble polyester resin and a nitrogen / phosphorous powder flame retardant. An automobile seat device using the heating element according to any one of claims 9 to 11 as a heat source for heating.