JP2009193689A - Polymer resistor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer resistor in which variation magnification is improved without changing the filling amount of a carbon system material and also flexibility is added, and its manufacturing method. <P>SOLUTION: The polymer resistor includes a resin composition in which the main component is crosslinked through a reactive resin and a carbon system material, and contains a liquid substance 10 wt% or more at normal temperature. Thereby, variation magnification is improved without changing the filling amount of the carbon system material, and also flexibility is added. As a liquid substance, a phosphate system compound and a silicon system compound are listed up. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer resistor having a positive resistance temperature characteristic, and more particularly to a polymer resistor having both a low resistance value and a high change ratio, and a method for manufacturing the same.

  Conventionally, a PTC resistor having a positive resistance temperature characteristic has been used as a heating element (heater). The positive resistance temperature characteristic means that the resistance value of the resistor increases as the temperature rises, and increases rapidly when reaching a certain temperature.

  Here, a resistance change magnification which is a ratio of a resistance value of 50 ° C. and a resistance value of 20 ° C. is defined as a change magnification.

  As the PTC resistor, one formed by mixing a crystalline resin and a conductive material is widely known.

  The principle is that, as a result of the rapid volume expansion when the crystalline resin is converted from crystalline to amorphous, the average interparticle distance of the conductive material dispersed therein increases, resulting in a resistance value. Are also expected to increase.

  Since the PTC resistor based on such a principle has a self-temperature control function by itself, there is an advantage that the number of components can be reduced without providing a safety device such as a thermostat.

  FIG. 3 shows an example in which the PTC resistor 17 is printed on the electrode 16 disposed on the resin film 15 and dried.

  In addition, there is a configuration in which a protective film is laminated thereon.

However, in any case, the planar heating element is composed of only one type of uniform PTC resistor 17, and the change magnification is as small as less than 2 (see, for example, Patent Document 1).
JP 2001-357966 A

  In the conventional configuration, when the filling amount of the conductive carbon-based material is increased in order to reduce the resistance value, the rate of change is reduced and the flexibility is also lowered.

  On the other hand, if the filling amount of the carbon-based material is reduced to increase the resistance value, the change ratio increases, but the desired resistance value cannot be obtained.

  The present invention solves the above-described conventional problems, and provides a planar heating element and a method for manufacturing the same that improve the change ratio without changing the filling amount of the carbon-based material and also provide flexibility. Objective.

  In order to solve the above-described conventional problems, the main component has a resin composition and a carbon-based material cross-linked through a reactive resin, and contains 10 wt% or more of a liquid substance at room temperature. Is.

  As a result, the change magnification can be increased without changing the resistance value.

  According to the present invention, a polymer resistor having a large resistance change rate can be produced.

  The first invention is characterized in that the main component has a resin composition crosslinked with a reactive resin and a carbon-based material, and contains 10 wt% or more of a liquid substance at room temperature.

  Since the liquid substance has a large volume expansion due to temperature change, if the temperature of the resistor containing the liquid substance rises, the distance between the particles of the carbon-based material increases, and the resistance value increases remarkably.

  Thereby, the change magnification can be improved without changing the addition amount of the carbon-based material.

  In the second invention, in particular, the liquid substance of the first invention is a phosphate ester compound.

  The phosphorus compound functions as a flame retardant because it acts as a dehydrating agent during combustion in the presence of an oxygen-containing compound and promotes the formation of a carbonized film. Among them, phosphate ester is liquid at normal temperature and compatible with resin.

  Therefore, it is possible to improve the change ratio and to impart flame retardancy.

  In the third invention, in particular, the liquid material of the first invention contains a silicon compound.

  In the composition to which these compounds are added, since the surface energy is small, the releasability is improved, for example, when a resistor is formed by calendering.

  Therefore, the change magnification can be improved and the workability can be improved.

  In a fourth invention, these polymer resistors are used in a planar heating element.

  According to a fifth aspect of the present invention, the planar heating element of the fourth aspect of the present invention is attached to at least one of a seat portion and a backrest of an automobile seat and used for heating.

  6th invention has the 1st process for the liquid substance adsorption | suction carbon material manufacture which stirs and mixes a liquid substance and carbonaceous material, and the 2nd process of knead | mixing the said liquid substance adsorption | suction carbon material and resin composition. It is a manufacturing method characterized by this.

  After the carbon material is kneaded with the resin, it is difficult to add 10 wt% or more of the liquid substance because the liquid substance repels. Or it needs to be dripped slowly and requires time.

  On the other hand, the carbon-based material has a large specific surface area and can absorb liquid.

  Therefore, the liquid substance can be easily mixed by dividing into the first process for holding the liquid substance in advance and the second process for kneading with the resin.

In particular, the seventh invention is characterized in that in the production method of the sixth invention, there is a step of reducing the carbon-based material.

  On the surface of the carbon-based material, basic functional groups and the like generated in the manufacturing process of the carbon-based material are attached, and the interfacial resistance between the particles is large. Therefore, the interface resistance can be reduced by removing the deposits by performing a reduction treatment.

  That is, the resistance value can be reduced without reducing the change magnification. In other words, the change magnification can be improved without changing the resistance value.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present embodiment does not limit the present invention.

(Embodiment 1)
FIG. 1 shows an example used for a planar heating element.

  The planar heating element 1 includes an electrically insulating substrate 2, a filament electrode 3 composed of first and second filament electrodes 3 </ b> A and 3 </ b> B, and a polymer resistor 4.

  The linear electrodes 3A and 3B are arranged on the electrically insulating base material 2 so as to be symmetrical with each other, and are partially sewn with a thread 5.

  The polymer resistor 4 is formed on the electrically insulating base material 2 on which the line electrodes 3 are arranged by being processed into a film by a calendering method.

  As a result, the polymer resistor 4 is thermally fused to the filament electrode 3 and the electrically insulating substrate 2.

  The central portion of the sheet heating element 1 is punched after the polymer resistor 4 is thermally fused to the linear electrode 3 and the electrically insulating base material 2.

  Thus, the planar heating element 1 is configured. In addition, the lead wire for supplying the electric power from a power supply to the filament electrodes 3A and 3B is not illustrated. Further, the punching 6 in the central portion is not limited to this place, and may be provided in other places depending on the material and shape of the attachment site. In this case, the wiring pattern of the line electrode 3 is changed.

  FIG. 2 shows an example in which the planar heating element 1 is attached to a seat of an automobile, that is, the planar heating element 1 is a seat 7 as a heater for heating or a backrest provided so as to stand up from the seat 7. 8 is attached so that the electrically insulating base material 2 is arranged on the surface side.

  A seat base 9 and an outer skin 10 are used for the seat 7 and the backrest 8.

  The seat base material 9 such as a urethane pad is deformed when a load is applied by a human body seated on the seat, and the shape is restored when the load is no longer applied.

  In addition, in order to correspond to the hanging part (not shown) of the seat part 7 and the backrest 8, the extension part (not shown) of the electrically insulating base material 2 for hanging in the center part or the peripheral part is provided. There may be.

  Thus, the thin planar heating element 1 is disposed along the seat base 9 and the skin 10 which can be deformed.

  Therefore, the planar heating element 1 must be similarly deformed corresponding to the deformation of the seat 7 and the backrest 8.

  Therefore, it is necessary to design various heat generation patterns and to change the arrangement shape of the line electrodes 3 therefor, but details thereof are omitted here.

  A pair of wide linear electrodes 3 </ b> A and 3 </ b> B arranged so as to face each other are disposed along the outer side in the longitudinal direction of the planar heating element 1.

  The polymer resistor 4 disposed so as to overlap the linear electrodes 3A and 3B generates heat when power is supplied through the linear electrodes 3A and 3B.

  The polymer resistor 4 has PTC characteristics, 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 4 gives the planar heating element 1 a function that is highly safe and does not require temperature control.

  In addition, as a car seat heater incorporated in an automobile seat, the planar heating element 1 can satisfy a seating feeling and flame retardancy.

  The seating sensation is satisfactory because 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 an elongation of 5%.

  In addition, the planar heating element 1 having the PTC characteristic can exhibit quick heat and energy saving as compared with the heating element having no PTC characteristic.

  A heating element having no PTC characteristic requires a temperature controller, and the temperature controller controls the heat generation temperature by controlling energization by ON-OFF control. In particular, in the case of a heating element having a PTC characteristic using a filament heating wire, the heating element temperature at the time of ON is raised to about 80 ° C. in order to avoid a low temperature portion between the filament heating wires. However, in the planar heating element 1 of the present embodiment, the heating element temperature is self-controlled within the range of 40 ° C to 45 ° C. Therefore, it can be arranged close to the vicinity of the skin 10.

  The sheet heating element 1 has a low heating element temperature and is disposed in the vicinity of the skin 10, so that it is possible to reduce the rapid heating property and heat dissipation loss to the outside. Therefore, energy saving can be realized.

  As described above, in the planar heating element 1 of the present embodiment, the conventional planar heating element has a 5-6 layer structure of a base material, an electrode, a polymer resistor, a heat-fusible resin, and a coating material. In contrast to this, it has a three-layer structure of an electrically insulating substrate 2, a pair of filament electrodes 3, and a polymer resistor 4.

  With this simple configuration, even when an external force is applied, the restriction of the external force is reduced, and thus flexibility is easily exhibited.

  Therefore, even when subjected to an external force when used as a car seat heater, it is highly flexible and easily deformed, and cracking and peeling of the polymer resistor caused by creases as in the prior art are prevented.

  Further, the planar heating element 1 can be manufactured with a simple configuration of three layers, so that the productivity is excellent and the material cost for configuring the planar heating element 1 is reduced. As a result, it can be produced at low cost.

  Further, since a resin film such as a non-breathable polyester sheet is not used with the polymer resistor 4 interposed therebetween, moisture is likely to be trapped when used for a car seat heater or a handle heater as in a conventional sheet heating element. This solves the problem, and even when used for a long time, a seating feeling and a touch feeling equivalent to those in the initial stage can be obtained, and a comfortable heating effect can be obtained.

  As the electrically insulating base material 2, for example, a needle punch type nonwoven fabric made of polyester fiber is used. Besides this, a polyester woven fabric may be used.

  These electrically insulating base materials 2 impart flexibility to the planar heating element 1 and easily deform even when an external force is applied to improve the seating feeling when used as a car seat heater.

  In particular, when the filament electrode 3 is attached by sewing, the above nonwoven fabric and woven fabric are optimal in terms of prevention of cracks generated from the needle holes of the electrically insulating base material 2 by sewing and flexibility.

  The filament electrode 3 is attached to the electrically insulating base material 2 by sewing with a sewing machine or the like. According to the structure produced by this method, the linear electrode 3 can be firmly fixed to the electrically insulating substrate 2 and can be deformed following the deformation of the electrically insulating substrate 2, thereby improving the mechanical reliability. .

  Moreover, since the sewing to the electrically insulating base material 2 is performed by the thread 5, the selection range of the electrode material and the shape is expanded.

  Furthermore, unlike the conventional complicated comb-shaped electrode, the line electrode 3 can be a simple configuration having at least a pair of linear shapes, so that the material cost is low and the cost can be reduced.

  Further, even when an external force is applied when used as a car seat heater, the generation of wrinkles on the filament electrode 3 is suppressed, and the electrode is prevented from being damaged.

  The wire electrode 3 is composed of at least one of a metal conductor and a metal braided conductor. These materials are easy to sew to the electric base material insulation 2 and have high productivity.

  Further, the selection range of the material and shape of the metal conductor and the metal braided conductor is widened. Metal conductors and metal braided conductors have excellent flexibility and high mechanical strength, so that they can endure for a long period of time even if the planar heating element is repeatedly elongated, bent, or deformed.

  In addition, since the electrode is composed of a filament, unlike the conventional complicated comb-shaped electrode, it can have a simple structure, and the cost of the electrode material can be reduced.

  It is preferable that the resistance of the line electrode 3 is as low as possible and the voltage drop is small. The linear electrode 3 has a suitable resistance value at which the voltage drop of the voltage applied to the planar heating element 1 is 1 V or less.

  Moreover, since the unevenness | corrugation will be formed in the planar heat generating body 1 and the seating feeling will be impaired when the wire diameter of the filament electrode 3 is large, diameter 1mm or less is preferable, and also diameter in order to implement | achieve a more comfortable seating feeling. 0.5 mm or less is good.

  Examples of the material that realizes the resistance value include copper, tin-plated copper, copper-silver alloy single wire, stranded wire, and braided wire. Particularly, in terms of mechanical strength, it is preferable to use copper-silver having high tensile strength.

In this embodiment, the line electrode 3 is used as an electrode. However, the present invention is not limited to this, and a metal foil electrode, an electrode film by screen printing such as a silver paste, or the like can also be used.

  By the way, in order to reproduce, what mixed the modified polyethylene which has a carboxyl group as a to-be-reacted resin which expresses PTC, and the modified polyethylene which has an epoxy group as a reactive resin to react with a to-be-reacted resin is good.

  This is because the carbonyl group of the reactive resin reacts with the oxygen of the epoxy group of the reactive resin to be chemically bonded and has a crosslinked structure.

  By this crosslinking reaction, as described above, the thermal stability can be improved compared to the case of the resin alone, and as a result, the temperature at which the conductive path of the conductor in the resin composition is formed and cut is reduced. Stabilize.

  This cross-linking reaction can occur even through nitrogen in addition to oxygen. If a combination of a reactive resin having a functional group containing at least one of oxygen and nitrogen and a reactive resin having a functional group capable of reacting with these functional groups, a crosslinking reaction will occur, and the resin composition As a combination of the reactive functional group of the reactive resin and the functional group of the resin to be reacted, there are the following in addition to the above-described epoxy group and carbonyl group.

  The epoxy group undergoes addition polymerization by reacting with a carboxyl group, an ester group, a hydroxyl group, an amino group, a vinyl group, a maleic anhydride group, or an oxazoline group in addition to the above carbonyl group. A reaction resin having these functional groups may be used.

  On the other hand, as a functional group of the reactive resin, a reactive resin having an oxazoline group or a maleic anhydride group in addition to an epoxy group can be used. Thus, the resin composition has a structure crosslinked through at least one of oxygen and nitrogen.

  When the exothermic temperature is relatively low as 40 to 50 ° C. like a car seat heater, a modified olefin resin that is a low melting point resin such as an ethylene vinyl acetate copolymer, It is preferable to use ester ethylene copolymers such as ethylene ethyl acrylate copolymer, ethylene methyl methacrylate copolymer, ethylene methacrylic acid copolymer, and ethylene butyl acrylate.

  The above-mentioned reactive resin and reactive resin can be used either individually or in combination, and are appropriately selected according to the target PTC characteristics.

  In addition, it is also possible to use a reactive resin or a reactive resin alone depending on the allowable range of change with time in PTC characteristics.

  Moreover, although reactive resin was used for the crosslinking reaction, the crosslinking agent different from reactive resin can also be used.

  Furthermore, crosslinking means such as an electron beam can be used. In that case, the above-described reactive resin having no functional group is applicable, and it is not necessary to use a reactive resin.

  As the carbon-based material, carbon black having an average particle diameter of several tens of μm is used. The filling amount is 40 to 50 wt%.

As the liquid substance, the phosphate ester compound is preferably an aromatic compound, and bisdiphenyl phosphate is used. The viscosity is several 500 mm 2 / s (25 ° C.). In the case of calender roll processing, silicone oil is used as the liquid material. Either one of the phosphate ester compound and the silicone oil can be used, or both can be used in combination.

  Next, an example of a method for manufacturing the planar heating element 1 will be described.

  First, an electrically insulating base material 2 made of polyester fiber non-woven fabric is formed by twisting 19 copper-silver alloy wires having a diameter of 0.05 .mu.m into a shape shown in FIG. Then, the line electrode 3 is formed.

  The distance between the electrodes of the pair of filament electrodes 3 at this time is 100 mm.

  Next, it is kneaded and mixed with a resin to be reacted, a reactive resin, and a conductor, which exhibit PTC characteristics, and molded into a film by a calendar device.

  In this way, the polymer resistor 4 is produced. In addition, kneading | mixing mixing is performed with apparatuses, such as a hot roll, a kneader, and a biaxial kneader.

  The thickness of the polymer resistor 4 is not particularly limited, but 20 to 200 μm is appropriate in terms of flexibility, material cost, appropriate resistance value, and strength when a load is applied. 30-100 micrometers is good.

  Next, the polymer resistor 4 molded into a film and taken out from the calender roll is composed of a surface of the electrically insulating base material 2 on which the prefabricated linear electrode 3 is attached and a laminator. Are heat-sealed and bonded together. The planar heating element 1 is completed as described above.

  The linear electrode 3 and the polymer resistor 4, and the electrically insulating substrate 2 and the polymer resistor 4 are joined by thermal fusion, respectively. It arrange | positions in the state electrically connected between the resistors 4.

  The polymer resistor 4 is made of a flexible sheet or film, so that even if an external force is applied to the planar heating element 1, the polymer resistor 4 itself responds to the external force in the same manner as the electrically insulating substrate 2. Since elongation and deformation occur, breakage such as cracks and breaks of the polymer resistor 4 is prevented, and excellent durability is realized.

  Further, by forming the polymer resistor 4 in the form of a sheet or film, the film thickness can be made thicker than the polymer resistor of the printed film, and electrical connection and mechanical joining with the line electrode 3 can be achieved. The reliability will be higher.

  Furthermore, since the polymer resistor 5 continuously extruded can be bonded while being bonded to the electrically insulating substrate 2 to which the filament electrode 3 is attached, the productivity is excellent and low cost can be realized.

  In addition, it is preferable that the polymer resistor 4 has an elongation equal to or greater than that of the electrically insulating substrate 2.

  By making the elongation of the polymer resistor 4 equal to or greater than that of the electrically insulating substrate 2, the electrically insulating substrate 2 having a high mechanical strength can regulate elongation and deformation due to external force, and thus is more excellent. Durability and reliability.

  Moreover, the polymer resistor 4 is affixed to the electrical insulating base material 2 to which the linear electrode 3 is previously attached by disposing the polymeric resistor 4 on the electrical insulating base material 2 and the linear electrode 3. A manufacturing method can be adopted.

  According to this manufacturing method, since the polymer resistor 4 immediately after molding is in a high temperature state, it is easily and firmly bonded to the linear electrode 3 and the electrically insulating substrate 2.

  As a result, electrical connection and mechanical joining can be obtained stably.

  Furthermore, by thermally fusing the polymer resistor 4 to the filament electrode 3, the material of the polymer resistor 4 is transferred around the filament electrode 3, and the filament electrode 3 and the polymer resistor 4 are dotted. Instead of bonding, surface bonding can be used.

  As a result, mechanical joining and electrical connection between the line electrode 3 and the polymer resistor 4 become strong, and an electrically and mechanically stable planar heating element 1 can be obtained.

  The planar heating element 1 configured as described above is preferably arranged and used on the seat portion 7 and the backrest 8 so that the electrically insulating base material 2 is on the surface side.

  That is, with the cushioning property of the electrically insulating base material 2, the unevenness due to the thickness and hardness of the line electrode 3 is not felt on the seating surface, and the seating feeling and the backrest feeling are not impaired.

  In Table 1, when 3 wt% of phosphate ester is added (No. 1), when 10 wt% is added (No. 2), when 15 wt% is added (No. 3), and when 10 wt% of silicone oil is added ( No. 4) shows the resistance value, change magnification, flame retardancy and releasability of the resistor produced.

From this result, the following can be derived.

  That is, by adding 10 wt% and 15 wt% of phosphoric acid ester, the change magnification becomes 2.0 or more.

  Moreover, a flame retardance can be provided by adding 15 wt% of phosphate ester.

  Furthermore, the releasability was improved by adding 10 wt% of silicone oil as a liquid substance.

  Here, the judgment of the flame retardancy was ○ when the flame disappeared naturally when the flame was ignited. Also, the judgment of releasability was evaluated as ◯ when the resin composition was easily peeled off from the calender roll and could be processed to a normal thickness in calender roll processing.

(Embodiment 2)
Only the differences from the first embodiment will be described.

  First, using a vacuum electric furnace, the carbonaceous material is reduced at 900 ° C. for 9 hours in a nitrogen atmosphere. Next, 50 wt% of the carbon-based material and 15 wt% of the phosphate ester compound are stirred and mixed. At this time, it is preferable to use a Henschel mixer.

  Next, a resin to be reacted that exhibits PTC characteristics, a carbon-based material holding a reactive resin, and a phosphate ester compound are kneaded and mixed and formed into a film by a calendar device.

  In this way, the polymer resistor 4 is produced. In addition, kneading | mixing mixing is performed with apparatuses, such as a hot roll, a kneader, and a biaxial kneader.

  The resin film forming method is not limited to the calendar device, and a T-die method and a printing method are also good.

  The thickness of the polymer resistor 4 is not particularly limited, but 20 to 200 μm is appropriate in terms of flexibility, material cost, appropriate resistance value, and strength when a load is applied. 30-100 micrometers is good.

  In the polymer resistor 4 produced as described above, by reducing the carbon-based material, it was possible to reduce the resistance value to ½ to 1/10 compared to those not subjected to the reduction treatment.

  Moreover, the liquid substance could be taken in by easily adsorbing the phosphoric ester compound to the carbon-based material in advance, and it could be easily processed.

  The polymer resistor according to the present invention has a simple structure and is particularly excellent in PTC characteristics. This polymer resistor can be mounted on the surface shape of appliances such as a continuous curved surface or a combination of flat surfaces, for example, as a planar heating element, so it requires heating, such as a car seat, steering wheel, etc. It can be applied to appliances such as electric floor heating.

  In addition, since the productivity is excellent and the cost can be reduced, the application range of applied products is expanded.

(A) is a top view which shows the planar heating element in Embodiment 1 of this invention, (b) is XY sectional drawing of (A). (A) is the see-through | perspective side view which shows the seat of the motor vehicle which attached the planar heating element in Embodiment 1 of this invention, (b) is the same sectional drawing. (A) is a perspective plan view of a conventional planar heating element, (b) is an XY sectional view of (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet-like heating element 2 Electrically insulating base material 4 Polymer resistor 7 Seat part 8 Backrest

Claims (7)

A polymer resistor comprising a resin composition having a main component crosslinked through a reactive resin and a carbon-based material, and containing 10 wt% or more of a liquid substance at room temperature. The polymer resistor according to claim 1, wherein the liquid substance is a phosphate ester compound. The polymer resistor according to claim 1, wherein the liquid substance contains a silicon compound. The planar heating element using the polymer resistor of any one of Claims 1-3. A sheet of an automobile in which the planar heating element according to claim 4 is attached to at least one of a seat part and a backrest. Production of a polymer resistor comprising a first step for producing a liquid substance adsorbing carbon material in which a liquid substance and a carbon-based material are stirred and mixed, and a second step in which the liquid substance adsorbing carbon material and the resin composition are kneaded. Method. The method for producing a polymer resistor according to claim 6, further comprising a step of reducing the carbon-based material.

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