JP2006324181A - Planar heating element - Google Patents

Abstract

The present invention provides a sheet heating element that can be used as a heat source for heating, heating, drying, etc., and realizes a highly reliable terminal connection and solves the problems at the time of processing the terminal member, thereby improving productivity. The purpose is to improve the above.
A terminal member 7 configured to connect a lead wire 8 for feeding power to a power feeding portion of an electrode 3 on one side, to form a conductive resin material on the other side, and to be surface-bonded to the electrode 3 has a corner portion. Since the curved chamfering is provided, curling from the corner portion can be reduced, and until the covering material 6 is disposed after surface bonding to the main electrodes 3a and 3b formed on the electrically insulating substrate 2 And the problem at the time of processing can be prevented, and the breakage of the terminal member 7 after turning the corner of the terminal member 7 can be prevented.
[Selection] Figure 2

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, this type of heating element is formed by previously forming solder on the lead connecting portion of the copper foil electrode where solder can be formed, covering the electrical insulating film thereon, forming a through hole in the electrical insulating film, and soldering. (See, for example, Patent Document 1).

  5 to 6 show conventional heating elements, in which a copper foil electrode 52 is bonded to an electrically insulating substrate 51 with a hot melt adhesive 53, and a heating element material is provided between the pair of copper foil electrodes 52. 54 is formed.

  The surfaces of the electrical insulating substrate 51, the copper foil electrode 52, and the heating element material 54 are covered with an electrical insulating film 55 with a hot melt adhesive. Solder 57 is formed in advance on the connection portion of the lead wire 56 to the copper foil electrode 52, and thereafter, the electrical insulating film 55 is covered.

The lead wire 56 is connected by heating the lead wire 56 on which the solder 57 is welded with a soldering iron to form a through hole in the electrically insulating film 55 with a hot melt adhesive, and joining with the solder 57 and the solder 57. The configuration is made possible.
Japanese Patent Laid-Open No. 57-202079

  However, in the conventional configuration, for example, even when trying to form a complicated electrode pattern with fine branches or curves, it is difficult to process with a method in which a metal foil material is attached to the substrate 51 with the hot melt adhesive 53. In practice, it has remained a simple parallel electrode pattern.

  Of course, it is possible to draw a complicated pattern by using an advanced process such as etching, but usually the area where the electrode is formed is extremely small, and most of the electrode material will be removed. In the case of a heating element with a large area, the situation was extremely poor in terms of resource saving and material cost.

  In addition, in an electrode made of a metal foil material, even if it is intended to form a heat generating body having elasticity and flexibility, there is a limit due to its strength being too strong, and durability when it is repeatedly expanded and bent is repeated. It was a big issue.

  On the other hand, when an electrode is formed by printing using a conductive paste in which silver powder is dispersed in an epoxy resin, it is easy to form a complicated electrode pattern with a curve, Although it can cope with flexibility, even if an attempt is made to solder the terminal portion before coating as in the case of a conventional heating element, the solder 6 cannot be formed because it is repelled by the resin component. Therefore, the configuration in which the lead wire 56 is soldered through the coating cannot be realized.

  Thus, when a material that cannot be soldered is used for the electrode, there are various methods for making a part of the electrode exposed after coating, and connecting the lead wire 7 to the part with a crimp terminal. It was general.

  In order to expose a part of the electrode after coating, an extra pattern such as extending or meandering so that a part of the electrode comes out of the coating is necessary. In addition, a release paper is provided on a part of the electrode, and a hole is made in that part after coating, or a hole is made in the coating, and processing is performed by a method such that the hole comes to a predetermined position of the electrode. It was necessary to complete the process.

  Note that the terminal connection by crimping involves a decrease in the crimping force due to resin shrinkage, and therefore, a special measure that does not increase the contact resistance is required. As a special case, it is not necessary to expose a part of the electrode, and a terminal of a type in which the terminal is bitten from the outside of the coating has been devised, but there is a limitation on the current, and it could not be used for applications with a large current .

  As described above, the conventional heating element cannot be branched finely or form a complicated electrode pattern with a curve, and has poor flexibility and stretchability. It was possible to connect. On the other hand, in the case of an electrode made of a conductive paste that can be printed, it is easy to form a complicated electrode pattern that is finely branched or curved, and can handle flexibility and stretchability. The lead wire could not be connected with solder from outside.

  In addition, the alternative lead wire connection method has various problems such as a complicated configuration and process, a need for measures against contact resistance due to resin shrinkage, and inability to use with a large current.

  The present invention enables lead connection by solder even for an electrode using a material that cannot be soldered, and not only is excellent in terminal formation productivity, but also has a large allowable current and reliability. An object of the present invention is to provide a planar heating element having excellent terminal connection.

  In particular, the surface of the heating element is coated even on materials that are not capable of soldering, such as printed electrodes that use conductive paste, which are excellent in pattern formability, flexibility, stretchability, etc. In this state, lead wires can be connected by solder.

  In addition, it significantly improves the allowable current and reliability when using such an electrode, such as a low-voltage heating element that requires a large amount of current, and a positive resistance temperature that causes a large current during inrush. This is extremely useful when forming a heating element having characteristics.

  In order to solve the above problems, a planar heating element of the present invention comprises a polymer resistor that is fed by an electrode formed on an electrically insulating substrate, and a lead wire that feeds a feeding part of the electrode on one side. A terminal member configured to be connected and formed with a conductive resin material on the other surface and surface-bonded to the electrode; and the electrode, the terminal member, and the polymer resistor are covered and placed in close contact with the electrically insulating substrate. And the terminal member has a curved chamfer at the corner.

  With the above-described configuration, the terminal member formed in the electrode power feeding portion is joined to the electrode via a conductive resin material, so that electrical and physical joining is possible regardless of the material of the electrode. The printable electrode material can hardly be connected by soldering. However, the terminal member can be surface-bonded through the conductive resin material, and the terminal member can be soldered.

  According to the above connection method, since the conductive resin material can be formed into a thin planar shape, the junction resistance value can be made extremely low, so that a large current can flow and the planar shape is joined. By doing so, sufficient strength can be secured.

  In addition, since the terminal member has a curved chamfer at the corner portion, curling from the corner portion can be reduced, and the covering material is disposed after surface bonding to the electrode formed on the electrically insulating substrate. In addition to preventing the positional deviation until the end of the process, the problems during processing can be eliminated, and the covering material after the covering material is disposed can be prevented from being broken by turning the corner portion of the terminal member.

  The planar heating element of the present invention can draw a complicated electrode pattern and is excellent in flexibility. On the other hand, even in the case of an electrode formed by printing in which solder connection is often impossible, a lead wire is formed by solder. In addition to being extremely excellent in productivity, it is an extremely strong joint both electrically and physically, withstands high currents, and is highly reliable.

  Furthermore, it is extremely useful when a large amount of current is required because the power supply voltage is low, or when a heating element having a positive resistance temperature characteristic that requires a large inrush current to obtain rapid thermal performance is used. is there.

  Further, since the terminal member is provided with a curved chamfer at the corner portion, curling from the corner portion can be reduced, and the covering material is disposed after surface bonding to the electrode formed on the electrically insulating substrate. In addition to preventing the positional deviation until the end of the process, the problems during processing can be eliminated, and the covering material after the covering material is disposed can be prevented from being broken by turning the corner portion of the terminal member.

  In other words, since there is no edge of the corner portion of the terminal member, it is possible to prevent the terminal material from being exposed from the coating material by breaking through the coating material at the corner portion of the terminal member, and to ensure safety against leakage etc. Even if the lead wire connected to the terminal member is pulled, the covering material does not break through and peel off from the edge of the corner portion of the terminal member, and the adhesive strength of the terminal member is reinforced by the covering material. Become.

  In the first invention, an electrically insulating substrate, an electrode formed on the electrically insulating substrate, a polymer resistor that is fed by the electrode, and a lead wire that feeds the feeding portion of the electrode are connected to one side. A terminal member configured to form a conductive resin material on the other surface and surface-bonded to the electrode, and a covering material disposed in close contact with the electrically insulating base material covering the electrode, the terminal member, and the polymer resistor The terminal member has a corner portion with a curved chamfer.

  And since the terminal member formed in the power feeding part of the electrode is joined to the electrode through a conductive resin material, it can be electrically and physically joined regardless of the material of the electrode, and in particular, printing is possible. However, the electrode member can hardly be connected to the solder, but the terminal member can be surface-bonded through the conductive resin material, and the terminal member can be connected to the solder. According to the above connection method, since the conductive resin material can be formed into a thin planar shape, the junction resistance value can be made extremely low, so that a large current can flow and the planar shape is joined. By doing so, sufficient strength can be secured.

  In addition, since the terminal member has a curved chamfer at the corner, curling from the corner can be reduced, and the covering material is disposed after surface bonding to the electrode formed on the electrically insulating substrate. It is possible to prevent misalignment until it is done, and to solve the problems at the time of processing, and to prevent the coating material after the coating material is disposed from being pierced by turning the corner portion of the terminal member.

  In other words, since there is no edge of the corner portion of the terminal member, it is possible to prevent the terminal material from being exposed from the coating material by breaking through the coating material at the corner portion of the terminal member, and to ensure safety against leakage etc. Even if the lead wire connected to the terminal member is pulled, the covering material does not break through and peel off from the edge of the corner portion of the terminal member, and the adhesive strength of the terminal member is reinforced by the covering material. Become.

  Moreover, since the breakage by the terminal member can be prevented, the terminal member is protected by the electrically insulating base material and the covering material disposed in close contact therewith, and is configured to be shielded from the outside air, and is contaminated by moisture and foreign matter. Defects such as deterioration and short-circuiting due to electrode migration can be prevented, and performance stability and durability can be further improved.

  In the second aspect of the invention, the terminal member of the first aspect of the invention is particularly configured to have a circular corner having no corners.

  And since the terminal member has a shape that does not have a corner at the corner portion like a circle, the turning from the corner portion can be further reduced, and the directionality is less with respect to the arrangement of the terminal member. Further, the disposition of the terminal member during processing is improved, and problems during processing such as the inclination of the disposition of the terminal member are also solved.

  In the third invention, the terminal member of the first invention is formed in such a way that the die removal direction is the burr direction on the electrode side.

  And since the die removal direction of the terminal member is formed in such a direction as to be a burr direction on the electrode side, there is no fear that the coating material will be pierced by the burr of the terminal member die removal, and the terminal member Since the burrs without the mold are difficult to be formed on the electrode formed on the electrically insulating substrate, the bondability between the terminal member and the electrode is improved.

  The fourth invention is particularly configured such that the conductive resin material of the terminal member of the first invention exhibits thermal adhesiveness to the electrode and is thermosetting.

  And since the conductive resin material of the terminal member shows a thermoadhesiveness with respect to the electrode and has a thermosetting structure, it is in an uncured state before the conductive resin material of the terminal member is joined to the electrode. Adhesion is possible by applying heat at the time of surface bonding, and volatile components are removed in the process of thermosetting by heat-adhering and curing when applying heat to the electrode, such as when attaching lead wires. Therefore, it does not foam and becomes a dense structure, and sufficient strength can be obtained. The original adhesive strength of the conductive resin material can be exhibited, and the terminal member can be reliably bonded to the electrode with a simple configuration.

  The fifth aspect of the invention is particularly configured such that a part of the terminal member of the first aspect on the coated surface side of the conductive resin material is subjected to adhesive treatment.

  In addition, since a part of the terminal member on the conductive resin material coated surface side is subjected to adhesive treatment, the covering material is disposed after surface bonding to the electrode formed on the electrically insulating substrate. Positional displacement until installation is prevented and workability is improved.

  In a sixth aspect of the present invention, an insulating protection process is applied to the die-cut part and the lead wire attachment part.

  And since it has a configuration in which an insulating protective material is applied, the electrode and the polymer resistor fed by the electrode from the die-cut portion and the lead wire mounting portion are protected by the insulating protective material and blocked from the outside air As a result, it is possible to prevent problems such as contamination deterioration due to moisture and foreign matter, and short-circuiting due to electrode migration, and the stability and durability of performance can be further improved.

  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 FIG. 1, a planar heating element 1 includes a pair of electrodes 3 formed by printing and drying a silver paste on a thin-walled electrically insulating substrate 2 such as a polyester film laminated on a polyester nonwoven fabric 2 a. The polymer resistor 4 is formed by printing and drying the polymer resistor ink so as to overlap the electrode 3.

  Then, a thin-walled electrically insulating overcoat such as a polyester film in which an adhesive resin layer 5 such as an acrylic adhesive having adhesiveness with the electrode 3, the polymer resistor 4, and the electrically insulating substrate 2 is formed in advance. The covering material 6 laminated with the coating material is bonded together.

  The electrode 3 is provided with wide main electrodes 3a and 3b so as to face each other, and a plurality of comb-shaped branch electrodes 3c and 3d are provided alternately from the main electrodes 3a and 3b, and overlap each other. When the polymer resistor 4 arranged as described above is fed from the branch electrodes 3c and 3d, a current flows and heat is generated.

  This polymer resistor 4 has PTC characteristics, and when the temperature rises, the resistance value of the polymer resistor 4 rises and has a self-temperature adjusting function so as to reach a predetermined temperature, so temperature control is unnecessary. Thus, it has a function as a highly safe planar heating element.

  In addition, a substantially circular terminal member 7 provided with a curved chamfer at the corner portion at a predetermined position of the electrode 3 is surface-bonded so that the die removal direction is a burr direction on the electrode side, and the covering material 6 The lead wire 8 is connected to the terminal member 7 from above.

  Further, an insulating protective material 9 such as a silicon adhesive is applied to the attachment portion of the lead wire 8 from above the covering material 6.

  A conductive resin material 7a is formed on the surface of the terminal member 7 in contact with the power feeding portion of the electrode 3, and the electrode 3 and the terminal member 7 are electrically and physically joined by the conductive resin material 7a. In addition, the conductive resin material 7a exhibits thermoadhesiveness with respect to the electrode 3 and is thermosetting, and silver powder is dispersed as a conductivity-imparting material in the copolymer polyester, and an appropriate amount of isocyanate is added as a curing agent. The conductive paste produced in this way is used.

  Since the conductive resin material 7a at this stage is dried at a low temperature so as not to cause a curing reaction due to isocyanate, it retains thermoplasticity, and heat is applied to the electrode 3 when pressed at a temperature equal to or higher than the melting point. It is in a state where it can be fused.

  In this case, in particular, when the same kind of resin is used as the conductive resin material 7 a for the electrode 3, the heat fusion property is extremely good and sufficient heat fusion strength can be obtained. In addition, adhesive processing, for example, small dot-shaped adhesive material 7b is dotted and printed on a part of the application surface side of the conductive resin material 7a of the terminal member 7, and the terminal member 7 is provided on the power feeding portion of the electrode 3. It is designed to be temporarily fixed when joining.

  Here, as an order of processing steps, first, a pair of electrodes is formed by printing and drying a silver paste on a roll-shaped thin insulating substrate 2 such as a polyester film laminated on a polyester nonwoven fabric 2a. 13 is formed.

  Next, the polymer resistor 4 is formed by printing and drying the polymer resistor ink so as to overlap the electrode 3. Then, after temporarily fixing the terminal member 7 with the adhesive material 7b so that the surface on which the conductive resin material 7a is formed contacts the power feeding portion of the electrode 3, the portion of the terminal member 7 is pressurized at a predetermined temperature for a predetermined time, After the electrode 3 and the terminal member 7 are surface-bonded, an adhesive resin layer 5 such as an acrylic adhesive having adhesiveness with the electrode 3, the polymer resistor 4, and the electrically insulating substrate 2 is formed in advance. A covering material 6 laminated with a thin electrical insulating overcoat material such as a polyester film is laminated to form a heating element body portion.

  Next, after the outer shape of the heating element main body is removed, the lead wire 8 is connected to the terminal member 7 with the solder 10 from above the covering material 6, and finally, a silicon adhesive or the like is attached to the attachment portion of the lead wire 8. The insulative protective material 9 is applied to complete the assembly.

  Here, since the terminal member 7 has a substantially circular shape with a curved chamfered corner portion, curling from the corner portion can be reduced, and the main electrodes 3a and 3b formed on the electrically insulating substrate 2 are in contact with each other. It is possible to prevent misalignment from when the covering material is disposed to when the covering material is disposed, so that problems during processing are eliminated, and the covering material 6 after the covering material 6 is disposed is turned over at the corner portion of the terminal member 7. It will be possible to prevent the breakthrough.

  That is, since there is no edge of the corner portion of the terminal member 7, the covering material 6 can be prevented from breaking through the corner portion of the terminal member 7, and the terminal member 7 can be prevented from being exposed from the covering material 6, thereby ensuring safety against electric leakage and the like. In addition, even when the lead wire 8 connected to the terminal member 7 is pulled, the covering material 6 is not pierced and peeled off from the edge of the corner portion of the terminal member 7, and the covering member 6 prevents the terminal member from peeling off. The adhesive strength of 7 is reinforced.

  Moreover, since the breakage by the terminal member 7 can be prevented, the terminal member 7 is protected by the electrically insulating base material 2 and the covering material 6 disposed in close contact therewith, and is configured to be shielded from the outside air. In addition, it is possible to prevent problems such as contamination deterioration due to contamination and foreign matter, and short-circuiting due to migration of the electrode 3, and the stability and durability of performance can be further improved.

  Further, since the terminal member 7 has a substantially circular shape in which the corner portion has a curved chamfer without a corner portion, curling from the corner portion can be further reduced and the direction with respect to the arrangement of the terminal member 7 can be reduced. Therefore, the disposition of the terminal member 7 during processing is further improved, and problems during processing such as the inclination of the disposition of the terminal member 7 are also solved.

  In addition, since the die removal direction of the terminal member 7 is formed to be a burr direction on the electrode 3 side, there is no fear that the covering material 6 is broken through by the burr of the terminal member 7 die removal, The burrs of the terminal member 7 without the die are inserted into the main electrodes 3a and 3b formed on the electrically insulating substrate 2, so that the bonding property between the terminal member 7 and the main electrodes 3a and 3b is improved.

  And since it is set as the structure which performed the adhesive process to a part by the side of the application surface of the conductive resin material 7a of the terminal member 7, surface bonding is carried out to the main electrodes 3a and 3b formed on the electrically insulating base material 2 Then, it is possible to prevent positional deviation between the time when the covering material 6 is disposed and the workability is improved, the productivity can be improved, and the structure can be reduced.

  Further, since the terminal member 7 formed at the power feeding portion of the main electrodes 3a and 3b is joined to the main electrodes 3a and 3b through the conductive resin material 7a, the electric and electrical Physical bonding is possible, and in particular, the printable electrode 3 material can hardly be connected to the solder 10, but the terminal member 7 can be surface-bonded through the conductive resin material 7a. 7 can be connected to the solder 10.

  And according to the above-mentioned connection method, since the conductive resin material 7a can be made extremely thin by forming it into a thin surface, a large current can be passed, and the surface By joining, sufficient strength can be secured.

  Therefore, it is possible to draw a complicated electrode 3 pattern and excellent flexibility. On the other hand, even if the electrode 3 is formed by printing, which is often impossible to connect the solder 10, the lead wire 8 is formed by the solder 10. It is possible, and it is extremely excellent in productivity, and at the same time it is an extremely strong electrical and physical bond, withstands high currents, and is highly reliable.

  Furthermore, it is extremely useful when a large amount of current is required because the power supply voltage is low, or when a heating element having a positive resistance temperature characteristic that requires a large inrush current to obtain rapid thermal performance is used. is there.

  Since the conductive resin material 7a of the terminal member 7 has a thermo-adhesive property to the electrode 3 and is thermosetting, the conductive resin material 7a of the terminal member 7 is joined to the main electrodes 3a and 3b. Before being done, it is in an uncured state and can be bonded by applying heat at the time of surface bonding. By applying heat to the main electrodes 3a and 3b at the time of attaching the lead wire 8 or the like, it is bonded and cured. In the process of thermosetting, since the volatile matter is removed, it does not foam, it becomes a dense structure, sufficient strength is obtained, the original adhesive strength of the conductive resin material 17a can be exhibited, and with a simple configuration The terminal member 7 can be surely surface-bonded to the main electrodes 3a and 3b.

  That is, since the terminal member 7 formed in the power feeding portion of the main electrodes 3a and 3b is joined to the main electrodes 3a and 3b via the conductive resin material 7a, the material of the main electrodes 3a and 3b is a copolymer polyester. Even a so-called resin-based conductive paste in which silver powder is dispersed as a conductivity-imparting material in a resin enables electrical and physical bonding. Naturally, even the main electrodes 3a and 3b such as thin metal plates can be electrically and physically joined, and the terminal member 7 can be joined without being restricted by the material of the main electrodes 3a and 3b.

  In addition, since the conductive resin material 7a is interposed in the form of a thin wall, it is possible to set the resistance value of the joint portion to be extremely low, and it is possible to hardly generate heat even if a large current is continuously applied. By securing the bonding area, sufficient strength can be ensured.

  Furthermore, since the covering material 6 formed on the outside of the terminal member 7 supports the terminal member 7, this bonding strength can be further strengthened. As a result, it is possible to form a highly reliable and highly productive power supply section with a large allowable current, and this configuration can provide a high heat resistance when a large amount of current is required because the power supply voltage is low. Therefore, it is extremely effective when forming a heating element having a positive resistance temperature characteristic that requires a large inrush current.

  In addition, since an insulating protective material 9 such as silicon adhesive is applied to the attachment portion of the lead wire 8, power is supplied from the attachment portion of the lead wire 8 by the main electrodes 3a and 3b and the main electrodes 3a and 3b. The polymer resistor 4 is protected by the insulating protective material 9 and is cut off from the outside air to prevent contamination deterioration due to moisture and foreign matter and short circuit due to migration of the main electrodes 3a and 3b. It is possible to improve the stability and durability of the performance.

  Further, since the terminal member 7 is also held by the insulating protective material 9, not only can the main electrodes 3a and 3b and the lead wires 8 be electrically connected stably but also physically and firmly. become able to.

  In the first embodiment, the adhesive treatment applied to a part of the application surface side of the conductive resin material 7a of the terminal member 7 is formed by printing with dot-shaped adhesive material 7b. However, this may be printed or applied to the end band on the application surface side of the conductive resin material 7a of the terminal member 7, or an adhesive member such as a double-sided tape may be used instead of printing the adhesive material 7b. Well, the terminal member has a substantially circular shape, but this may be a rectangular shape with a rounded corner, and the configuration of each of the other components is within the scope of achieving the object of the present invention. It may be something like this.

  As described above, the present invention enables lead wire connection by solder even for an electrode using a material that cannot be soldered with flexibility, and not only is excellent in productivity of terminal formation, Since the allowable current is large and it is possible to connect the terminal with excellent reliability, it can be applied to applications such as car seat heaters and handle heaters used mainly in vehicles, heating equipment and heating equipment. .

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 Enlarged view of the main part of the coplanar heating element Schematic perspective view of terminal portion of same-surface heating element The top view which shows the structure of the conventional planar heating element Cross-sectional view of coplanar heating element

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar heating element 2 Electrically insulating base material 3 Electrode 4 Polymer resistor 5 Adhesive resin layer 6 Coating material 7 Terminal member 7a Conductive resin material 8 Lead wire 9 Insulating protective material

Claims (6)

An electrically insulating substrate, a polymer resistor that is fed by an electrode formed on the electrically insulating substrate, a lead wire that feeds power to the feeding portion of the electrode is connected to one surface, and the other surface is connected A terminal member formed so as to be surface-bonded to an electrode by forming a conductive resin material, and a covering material that covers the electrode, the terminal member, and the polymer resistor and is disposed in close contact with the electrically insulating substrate The terminal member is a planar heating element in which a corner portion is provided with a curved chamfer. The planar heating element according to claim 1, wherein the chamfering is circular. The planar heating element according to claim 1, wherein the die removal direction of the terminal member is set to be a burr direction on the electrode side. The planar heating element according to claim 1, wherein the conductive resin material of the terminal member exhibits thermal adhesiveness to the electrode and is thermosetting. The planar heating element according to claim 1, wherein a part of the terminal member on the side of the conductive resin material coated surface is subjected to adhesive treatment. The planar heating element according to claim 1, wherein an insulating protection treatment is applied to a lead wire attachment portion.