Seat pads and sheet heaters

Abstract

To improve the ability of a sheet-shaped heater to conform to the surface shape of a cushion body and to prevent the sheet-shaped heater from shifting during use. [Solution] The seat pad (10) of the present disclosure has a sheet-type heater (30) fixed to a pad main body (11) made of polyurethane foam. The sheet-type heater (30) is formed by laminating an electrode layer (33) made of a wiring pattern with a self-temperature regulating function and a heat-generating layer (34) on an air-impermeable base sheet (31), the base sheet (31), the electrode layer (33), and the heat-generating layer (34) being made of an elastic material. The sheet-type heater (30) is integrally fixed to the surface of the pad main body (11).

Description

[Technical field]

[0001] The present disclosure relates to a seat pad equipped with a seat-like heater. Do Regarding. [Background technology]

[0002] Patent Document 1 discloses a sheet pad in which a sheet-shaped heater made of nonwoven fabric with an electric heating wire sewn onto it is fixed to the surface of the pad body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-347016 A (

[0033] to

[0034] , Figs. 1 and 2) Summary of the Invention [Problem to be solved by the invention]

[0004] The sheet pad of Patent Document 1 has a problem that it is difficult to make the sheet heater conform to the unevenness of the surface of the pad body when the surface is uneven. Also, if the sheet heater is fixed to a part of the pad body with double-sided tape or tack pins, the sheet heater is likely to shift during use. For this reason, there is a demand for improving the ability of the sheet heater to conform to the surface shape of the pad body and suppressing the shifting of the sheet heater during use. [Means for solving the problem]

[0005] A first aspect of the invention made to solve the above problems is a sheet pad having a sheet-type heater fixed to a pad body made of polyurethane foam, the sheet-type heater being formed by laminating an electrode layer made of a wiring pattern having a self-temperature regulating function and a heat generating layer on a non-breathable base sheet, the base sheet, the electrode layer and the heat generating layer being made of an elastic material, and the sheet-type heater being integrally fixed to the surface of the pad body.

[0006] A second aspect of the invention is the seat pad according to the first aspect, wherein a groove is formed on the surface of the pad body, the sheet-shaped heater has an inner groove entry portion fixed to the inner surface of the groove, and the wiring pattern is provided with a groove crossing portion arranged to cross the groove at the inner groove entry portion.

[0007] A third aspect of the invention is the sheet pad described in the second aspect, in which the cross-sectional area when the groove crossing portion is cut in a direction perpendicular to the extension direction of the wiring pattern is 0.8 to 1.2 times the cross-sectional area when the portion of the wiring pattern excluding the groove crossing portion is cut in a direction perpendicular to the extension direction of the wiring pattern.

[0008] A fourth aspect of the invention is a method for manufacturing a seat pad having a sheet-type heater fixed to a pad main body made of polyurethane foam, the sheet-type heater being formed by laminating an electrode layer made of a wiring pattern having a temperature self-regulating function and a heat generating layer on a non-breathable base sheet, the base sheet, the electrode layer and the heat generating layer being made of an elastic material, the sheet-type heater being shaped to the inner surface shape of a foam molding die by vacuum molding or pressure molding, and then a polyurethane raw material is injected into the foam molding die and foamed and cured, thereby integrally molding the pad main body and the sheet-like sheet.

[0009] A fifth aspect of the invention is a method for producing a seat pad according to the fourth aspect, wherein a concave-convex shape is provided on a portion of the inner surface of the foam molding die where the sheet-shaped heater is to be formed, and when forming the sheet-shaped heater, the wiring pattern is stretched to conform to the concave-convex shape.

[0010] A sixth aspect of the invention is a method for manufacturing a seat pad according to the fifth aspect, wherein, before forming the sheet-type heater, a cross-sectional area of ​​a portion of the wiring pattern that will stretch as the sheet-type heater is formed, when cut in a direction perpendicular to the extension direction of the wiring pattern, is made larger than a cross-sectional area of ​​a portion that will stretch less than the portion cut in a direction perpendicular to the extension direction of the wiring pattern.

[0011] In the first and fourth aspects of the invention, the term "non-breathable" refers to any amount of air permeable material that can be vacuum molded, and is, for example, the amount of air passing through a test piece (cm ) based on JIS L1096 A method (Fragile method): 2010. 3 / cm 2 ·s) is preferably equal to or less than the measurement limit value. The "elastic material" may be any material that has elasticity that can follow the surface shape of the pad body. For example, in the case of the base sheet, a thermoplastic resin sheet such as a polyethylene resin or a polypropylene resin, or a thermoplastic elastomer sheet such as a thermoplastic polyester elastomer (TPC) or a thermoplastic polyurethane elastomer (TPU) may be used. In the case of the electrode layer and the heat generating layer, it may be made of a thermoplastic elastomer such as a thermoplastic polyurethane elastomer (TPU), or a resin composition containing a binder having elasticity such as a rubber resin. Effect of the Invention

[0012] [First aspect of the invention] In the first aspect of the invention, the electrode layer and the heat generating layer are laminated, which stabilizes the current flowing through the electrode layer to heat the heat generating layer uniformly, and the amount of heat generated by the heat generating layer is uniform. In addition, the base sheet, electrode layer, and heat generating layer that make up the sheet heater are all made of elastic materials, which makes it easier for the sheet heater to conform to the surface shape of the pad body. Furthermore, the sheet heater is fixed integrally to the surface of the pad body, which reduces the displacement of the sheet heater during use.

[0013] [Second aspect of the invention] In the second aspect of the invention, the groove-crossing portion of the electrode layer crosses the groove formed on the surface of the pad body, so that the wiring pattern can be routed across two areas on either side of the groove on the surface of the pad body, thereby expanding the area that can be heated by one sheet heater.

[0014] [Third aspect of the invention] In the third aspect of the invention, the cross-sectional area of ​​the wiring pattern when the groove crossing portion is cut in a direction perpendicular to the extension direction of the wiring pattern is 0.8 to 1.2 times the cross-sectional area of ​​the portion excluding the groove crossing portion when cut in a direction perpendicular to the extension direction of the wiring pattern, so that even if the wiring pattern is arranged to cross a groove, the variation in the resistance of the wiring pattern is suppressed, and thus the variation in the heating temperature of the sheet-type heater is suppressed.

[0015] [Fourth aspect of the invention] In the fourth aspect of the invention, the base sheet, electrode layer, and heat generating layer constituting the sheet-like heater are all made of elastic materials, so that the sheet-like heater can be easily made to conform to the inner shape of the foam molding die. As a result, a sheet pad can be obtained in which the sheet-like heater conforms to the surface shape of the pad body. In addition, the sheet-like heater is shaped to the inner shape of the foam molding die by vacuum molding or pressure molding, and then polyurethane raw material is injected into the foam molding die to foam and harden, so that a sheet pad can be obtained in which the sheet-like heater is integrally fixed to the surface of the pad body, and displacement of the sheet-like heater during use is suppressed.

[0016] [Fifth aspect of the invention] According to the fifth aspect of the invention, the wiring pattern of the electrode layer is stretched when the sheet heater is shaped, so that the wiring pattern follows the uneven shape of the inner surface of the foam molding die, and therefore the wiring pattern can be routed regardless of the unevenness of the surface of the pad body, thereby expanding the area that can be heated by one sheet heater.

[0017] [Sixth aspect of the invention] According to the sixth aspect of the invention, even if the wiring pattern stretches as the sheet-type heater is shaped, the variation in cross-sectional area of ​​the stretched wiring pattern when cut in a direction perpendicular to its extension direction is suppressed, thereby suppressing the variation in the resistance of the wiring pattern and the variation in the heating temperature of the sheet-type heater. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1A is a perspective view of a vehicle seat in which a seat pad according to an embodiment of the present disclosure is used; FIG. 1B is a perspective view of the seat pad; [Diagram 2] Cross-sectional view of the seat pad cut in the front-to-rear direction [Diagram 3] Cross-sectional view of the seat pad cut in the left-right direction [Figure 4] Top view of the pad body [Diagram 5] (A) Cross-sectional view and (B) plan view of sheet heater [Figure 6] Cross-sectional view of the seat pad cut in the front-rear direction around the lateral groove [Figure 7] Cross-sectional view of the seat pad cut in the left-right direction around the vertical groove [Figure 8] Cross-sectional view showing the manufacturing process of the seat pad [Figure 9] Cross-sectional view showing the manufacturing process of the seat pad [Figure 10] Cross-sectional view showing the manufacturing process of the seat pad [Figure 11] (A) Cross-sectional view and (B) plan view of the sheet heater before shaping [Figure 12] (A) Cross-sectional view and (B) plan view of the sheet heater after shaping [Figure 13] (A) is a cross-sectional view of a seat pad according to another embodiment; (B) is a cross-sectional view showing a manufacturing process of the seat pad; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] 1(A) shows a vehicle seat 90 in which the seat pad 10 of the present embodiment is used. The vehicle seat 90 includes a seat cushion 91 serving as a seating portion, and a seat back 92 serving as a backrest portion. In the present embodiment, an example in which the seat pad 10 is used in the seat cushion 91 is shown, but the seat pad 10 may also be used in the seat back 92.

[0020] The seat cushion 91 is formed by covering the seat pad 10 shown in Fig. 1(B) with a cushion cover 20 (see Fig. 1(A)). The cushion cover 20 is formed by sewing together a plurality of cover pieces 21 (see Figs. 2 and 3).

[0021] 2 and 3, in the seat pad 10, a sheet-shaped heater 30 is fixed to the front side 11M of a pad main body 11 made of polyurethane foam. Note that an in-pad wire 12 for fixing a cushion cover 20 is embedded in the pad main body 11.

[0022] 4, the pad body 11 has a main portion 11A that receives the buttocks and thighs of a seated person, and side portions 11B, 11B that are raised from both sides of the main portion 11A relative to the main portion 11A. Also, a hanging groove 14 is formed on the front side surface 11M of the pad body 11.

[0023] The in-pad wires 12 in the pad body 11 are arranged along the hanging groove 14 (see Figs. 2 and 3), and a plurality of wire exposure holes 15 for exposing the in-pad wires 12 are formed in the bottom surface 14M of the hanging groove 14. In detail, the hanging groove 14 is provided with a pair (two lines) of vertical grooves 14A, 14A extending in the front-rear direction at the boundary between the main part 11A and the side parts 11B, 11B of the pad 11 body, and a plurality of horizontal grooves 14B connecting the pair (two lines) of vertical grooves 14A, 14A.

[0024] The cushion cover 20 is fixed to the seat pad 10, for example, in the following manner. That is, as shown in Fig. 2 and Fig. 3, one end of a connecting member 23 (e.g., a hanging cotton cloth) is joined to a sewn portion 22 between the skin pieces 21 of the cushion cover 20. Then, with the sewn portion 22 pulled into the hanging groove 14, the other end of the connecting member 23 and the in-pad wire 12 embedded in the seat pad 11 are connected by a hog ring (not shown), thereby fixing the cushion cover 20 to the pad main body 11.

[0025] 5(A) and 5(B) show the details of the sheet heater 30. As shown in FIG. 5(A), the sheet heater 30 includes a base sheet 31 and a planar heating element 32 stacked together, and the planar heating element 32 is disposed so as to face the pad body 11 (see FIGS. 6 and 7). The planar heating element 32 is formed by stacking an electrode layer 33 and a heating layer 34 that are formed separately. The electrode layer 33 is made of a wiring pattern having a self-temperature regulating function. As shown in FIG. 5(B), the size of the base sheet 31 is larger than that of the planar heating element 32, and the edge portion of the base sheet 31 is configured to protrude outside the planar heating element 32. In addition, the planar shape of the heating layer 34 is not particularly limited as long as it has a portion that overlaps with the electric heating layer 33.

[0026] The base sheet 31 is a resin sheet that is non-breathable and has elasticity, and is made of, for example, thermoplastic polyurethane elastomer (TPU), polyethylene (PE)-based resin, etc. In the present embodiment, the base sheet 31 is preferably a resin sheet made of TPU in view of elasticity, flexibility, adhesion to the polyurethane raw material that constitutes the pad body 11, etc. When the base sheet 31 is made of a PE-based resin, it is possible to improve adhesion to the polyurethane raw material by performing a surface treatment such as a corona treatment as necessary.

[0027] The electrode layer 33 is formed of a resin composition containing conductive particles and a binder made of a thermoplastic resin. The conductive particles preferably contain at least one metal filler such as silver, gold, copper, nickel, etc., and the inclusion of such a metal filler allows the formation of wiring with low electrical resistance. In particular, the conductive particles preferably contain silver, which has high electrical conductivity. The binder preferably contains, for example, a thermoplastic resin elastomer such as a thermoplastic polyester elastomer (TPC) or a thermoplastic polyurethane elastomer (TPU), or a rubber-based resin, and more preferably contains TPU, which has excellent elasticity and flexibility.

[0028] The resin composition forming the electrode layer 33 has elasticity and a resistance temperature characteristic (PTC characteristic) in which the resistance value increases with an increase in temperature and increases when a certain temperature is reached. This allows the electrode layer 33 to form wiring that has elasticity, conductivity, and PTC characteristics. In the example shown in Fig. 5(B), the wiring pattern of the electrode layer 33 is formed in a comb shape. In the figure, the electrode layer 33 is shown in gray to make it easier to recognize the wiring pattern.

[0029] The heat generating layer 34 is formed of a resin composition containing a heat generating element and a binder made of a thermoplastic resin. Examples of the heat generating element include carbon-based fillers such as carbon black, graphite, and graphene, and the inclusion of these carbon-based fillers can enhance heat generation. The binder preferably contains, for example, a thermoplastic resin elastomer or a rubber-based resin such as a thermoplastic polyester elastomer (TPC) or a thermoplastic polyurethane elastomer (TPU), and more preferably TPU, which has excellent elasticity and flexibility.

[0030] The resin composition forming the heat generating layer 34 has elasticity and a resistance temperature characteristic (PTC characteristic) in which the resistance value increases with an increase in temperature and increases when a certain temperature is reached. Therefore, the heat generating layer 34 of this embodiment can form a heat generating layer having elasticity, heat generation, and PTC characteristics. The resin composition forming the heat generating layer 34 may be a material that does not have a resistance temperature characteristic.

[0031] In this embodiment, by using the same material for the binders constituting the electrode layer 33 and the heat generating layer 34, it is possible to improve the adhesion between the electrode layer 33 and the heat generating layer 34 and to make their elasticity the same. As a result, it is possible to prevent the electrode layer 33 and the heat generating layer 34 from peeling off due to the difference in elasticity between them. Furthermore, if the binder constituting the electrode layer 33 and the heat generating layer 34 is configured to contain a thermoplastic polyurethane elastomer (TPU), it is possible to improve the adhesion between the base sheet 31, which is a resin sheet made of thermoplastic polyurethane elastomer (TPU), and the polyurethane raw material constituting the pad body 11.

[0032] In addition, in this embodiment, since the electrode layer 33 and the heat generating layer 34 formed separately are laminated, the amount of heat generated by the planar heating element 32 (sheet-like heater 30) is made uniform compared to the case where the electrode layer and the heat generating layer are integrally formed. The reason is as follows. That is, when the electrode layer and the heat generating layer are integrally formed, it becomes difficult to uniformly disperse the conductive particles contained in the electrode layer and the heat generating element contained in the heat generating layer, and the amount of heat generated by the planar heating element 32 becomes non-uniform. On the other hand, when the electrode layer 33 and the heat generating layer 34 formed separately are laminated, the conductive particles are uniformly dispersed in the electrode layer 33, so that the current flowing through the electrode layer 33 is stabilized, and the heat generating layer 34 can be heated uniformly. Furthermore, the heat generating element is uniformly dispersed in the heat generating layer 34, so that the amount of heat generated by the heat generating layer 34 is made uniform.

[0033] 5(B), the electrode layer 33 protrudes outward from the heat generating layer 34. A connection part 35 with the conductor 36 is formed in the protruding part of the electrode layer 33. The conductor 36 is fixed to the connection part 35 by a fixing tape (e.g., a nonwoven tape) (not shown).

[0034] 2 and 3, the sheet-shaped heater 30 follows the unevenness of the front surface 11M of the pad body 11, and the entire sheet-shaped heater 30 is fixed integrally to the front surface 11M of the pad body 11. Specifically, as shown in Fig. 3, the sheet-shaped heater 30 is disposed across the main part 11A and the side part 11B that rises from the main part 11A, and also follows the raised part of the front surface 11M formed by the side part 11B.

[0035] 6 and 7, the sheet-like heater 30 also fits the inner surface of the hanging groove 14 and has an in-groove entry part 40 that enters into the hanging groove 14. In detail, the in-groove entry part 40 is made up of a pair of side parts 40A, 40A fixed to the inner surface of the hanging groove 14, and a bottom part 40B fixed to the bottom surface 14M of the hanging groove 14.

[0036] The wiring pattern of the electrode layer 33 is provided with a groove crossing portion 43 arranged to cross the hanging groove 14 at the groove entry portion 40. In detail, the groove crossing portion 43 is composed of a side extension portion 43A extending along the side portion 40A of the groove entry portion 40, and a bottom extension portion 43B extending along the bottom portion 40B.

[0037] A cross-sectional area S1 when the groove crossing portion 43 is cut in a direction perpendicular to the extension direction of the wiring pattern is approximately the same as a cross-sectional area S2 when the other portion (hereinafter referred to as the "non-penetration portion") is cut in a direction perpendicular to the extension direction of the wiring pattern, and the resistance in the groove crossing portion 43 is approximately the same as the resistance in the portion of the wiring pattern of the electrode layer 33 excluding the groove crossing portion 43. Specifically, the cross-sectional area S1 of the groove crossing portion 43 is 0.8 to 1.2 times the cross-sectional area S2 of the non-penetration portion, and preferably 0.9 to 1.1 times.

[0038] In the sheet pad 10 of this embodiment, the base sheet 31, electrode layer 33, and heat generating layer 34 constituting the sheet-type heater 30 are all made of elastic materials, which makes it easier to make the sheet-type heater 30 conform to the shape of the front side surface 11M of the pad body 11. In addition, the sheet-type heater 30 is integrally fixed to the front side surface 11M of the pad body 11, which prevents the sheet-type heater 30 from shifting during use.

[0039] In addition, in the seat pad 10, the groove crossing portion 43 of the electrode layer 33 crosses the hanging groove 14 formed in the front side surface 11M of the pad body 11, so that the wiring pattern of the electrode layer 33 can be routed across two regions (for example, the main part 11A and the side part 11B that sandwich the vertical groove 14A) on the front side surface 11M of the pad body 11. As a result, the area that can be heated by one sheet-shaped heater 30 can be expanded.

[0040] Moreover, in the wiring pattern of the electrode layer 33, the cross-sectional area S1 of the groove crossing portion 43 is 0.8 to 1.2 times the cross-sectional area S2 of the non-penetration portion, so that the variation in resistance of the wiring pattern is suppressed even if the wiring pattern of the electrode layer 33 is disposed so as to cross the hanging groove 14. This suppresses the variation in the heat generation temperature of the sheet-type heater 30.

[0041] The seat pad 10 of this embodiment is manufactured as follows. First, a sheet-like heater 30 is prepared (see FIG. 8). Specifically, an electrode layer 33 and a heat generating layer 34 are formed in this order on a base sheet 31 by screen printing. The electrode layer 33 and the heat generating layer 34 are formed by dissolving a resin composition forming the electrode layer 33 and the heat generating layer 34 in a solvent to make it liquid, and then volatilizing the solvent after screen printing to harden the resin composition.

[0042] Here, a flat base sheet 31 is prepared, and the sheet-like heater 30 is formed to be approximately flat. In addition, the portion of the wiring pattern of the electrode layer 33 that overlaps with the side portion 11B of the pad body 11 is formed to have a larger cross-sectional area than the portion that overlaps with the main portion 11A by making the width of the wiring wider and / or the thickness (layer thickness) of the wiring thicker. In addition, in the wiring pattern of the electrode layer 33, the portion that becomes the groove entry portion 40 of the sheet pad 30, i.e., the portion that becomes the groove crossing portion 43, is formed to have a larger cross-sectional area than the portion that becomes the portion other than the groove crossing portion 43 by making the width of the wiring wider and / or the thickness (layer thickness) of the wiring thicker (see FIG. 11(A) and FIG. 11(B)).

[0043] Once the sheet-like heater 30 is prepared, the sheet-like heater 30 is then shaped into the shape of the inner surface of a foam molding die 50 by vacuum molding (see FIG. 9). Specifically, the foam molding die 50 is equipped with a first die 51 for molding the front side of the pad body 11 and a second die 52 for molding the back side of the pad body 11, and the sheet-like heater 30 is shaped into the shape of the molding surface of the first die 51. At this time, the sheet-like heater 30 is preferably disposed so that the base sheet 31 faces the first die 51. Note that since the base sheet 31 of the sheet-like heater 30 is non-breathable, vacuum molding can be suitably performed.

[0044] Next, polyurethane raw material 53 (see FIG. 9) is injected into the foam molding die 50 and foamed and cured. This forms the pad body 11, and a molded product is obtained in which the sheet-shaped heater 30 is fixed to the front side surface 11M of the pad body 11 (see FIG. 10). When this molded product is removed from the foam molding die 50, the seat pad 10 in which the pad body 11 and the sheet-shaped heater 30 are integrated is completed.

[0045] Meanwhile, the molding surface of the first die 51 is provided with side molding recesses 51A for molding the side portions 11B of the pad body 11, and groove forming protrusions 51T for molding the hanging grooves 14. Therefore, when the sheet-type heater 30 formed substantially flat is shaped to the shape of the molding surface of the first die 51, the sheet-type heater 30 is stretched so as to follow the shapes of the side molding recesses 51A and the groove forming protrusions 51T. As a result, the wiring pattern of the electrode layer 33 is also stretched so as to follow the shapes of the side molding recesses 51A and the groove forming protrusions 51T.

[0046] As described above, in the wiring pattern of the electrode layer 33 before the sheet-type heater 30 is shaped, the portion overlapping the side portion 11B is formed to have a larger cross-sectional area than the portion overlapping the main portion 11A, and the portion that will become the groove crossing portion 43 is formed to have a larger cross-sectional area than the portion that will become the portion other than the groove crossing portion 43. From another perspective, in the wiring pattern of the electrode layer 33, the cross-sectional area of ​​the portion that will stretch as the sheet-type heater 30 is shaped is larger than the cross-sectional area of ​​the portion that stretches less as the sheet-type heater 30 is shaped. Then, when the wiring pattern of the electrode layer 33 is stretched as the sheet-type heater 30 is shaped, the cross-sectional area of ​​the portion of the stretched wiring pattern overlapping the side portion 11B becomes approximately the same as the portion overlapping the main portion 11A, and the cross-sectional area of ​​the portion that becomes the groove crossing portion 43 becomes approximately the same as the portion that becomes the portion other than the groove crossing portion 43 (see Figures 12(A) and 12(B). These figures show a wiring pattern with uniform width and thickness.).

[0047] In the manufacturing method of the sheet pad 10 of this embodiment, the base sheet 31, the electrode layer 33, and the heat generating layer 34 constituting the sheet-like heater 30 are all made of elastic materials, so that the sheet-like heater 30 can be easily made to conform to the inner shape of the foam molding die 50 (specifically, the shape of the molding surface of the first die 51). As a result, a sheet pad 10 can be obtained in which the sheet-like heater 30 conforms to the shape of the front side surface 11M of the pad main body 11. In addition, the sheet-like heater 30 is shaped to the inner shape of the foam molding die 50 by vacuum molding, and then polyurethane raw material is injected into the foam molding die 50 and foamed and cured, so that a sheet pad 10 in which the sheet-like heater 30 is integrally fixed to the front side surface 11M of the pad main body 11 can be obtained, and displacement of the sheet-like heater 30 during use can be suppressed.

[0048] Furthermore, according to this embodiment, by extending the wiring pattern of the electrode layer 33 when forming the sheet-type heater 30, the wiring pattern is made to follow the uneven shape of the inner surface of the foam molding die 50 (more specifically, the shape of the side molding recess 51A and the groove forming protrusion 51T of the first die 51), so that it is possible to arrange the wiring pattern of the electrode layer 33 regardless of the unevenness of the front surface 11M of the pad body 11. As a result, the area that can be heated by one sheet-type heater 30 can be expanded.

[0049] Moreover, in the wiring pattern of the electrode layer 33 before the sheet-type heater 30 is shaped, the cross-sectional area of ​​the portion that will be stretched as the sheet-type heater 30 is shaped is made larger than the cross-sectional area of ​​the portion that will be stretched less as the sheet-type heater 30 is shaped, so that even if the wiring pattern of the electrode layer 33 stretches as the sheet-type heater 30 is shaped, variation in the cross-sectional area of ​​the stretched wiring pattern is suppressed. This suppresses variation in the resistance of the wiring pattern, and thus suppresses variation in the heat generation temperature of the sheet-type heater 30.

[0050] In this embodiment, the hanging groove 14 (more specifically, the vertical groove 14A and the horizontal groove 14B) corresponds to the "groove" described in the claims, and the non-penetration portion, which is the portion of the electrode layer 33 other than the groove crossing portion 43, corresponds to the "portion of the electrode layer excluding the groove crossing portion" described in the claims.

[0051] [Other embodiments] (1) As shown in Fig. 13(A), the sheet-type heater 30 may include a protective sheet 37 that sandwiches the planar heating element 32 between the base sheet 31 and the sheet-type heater 30. In this configuration, even if the sheet-type heater 30 is arranged so that the base sheet 31 faces the pad body 11, the planar heating element 32 is prevented from contacting the first die 51 of the foam molding die 50 (see Fig. 13(B)), thereby preventing the wiring pattern of the electrode layer 33 from being broken and the heating layer 34 from being peeled off.

[0052] (2) In the case where the vehicle seat 90 includes an ottoman in front of the seat cushion 91, the seat pad 10 may be applied to the ottoman.

[0053] (3) In the above embodiment, the sheet-shaped heater 30 is shaped by vacuum forming. However, it may be shaped by pressure forming, or may be shaped by a combination of vacuum forming and pressure forming.

[0054] (4) In the above embodiment, the electric heating layer 33 was laminated on the base sheet 31, and the heat generating layer 34 was laminated on the electric heating layer 33. However, the heat generating layer 34 may be laminated on the base sheet 31, and the electric heating layer 33 may be laminated on the heat generating layer 34. [Explanation of symbols]

[0055] 10 Seat pad 11 Pad body 14 Hanging groove 30 Sheet heater 31 Base sheet 32 Planar heating element 33 Electrode layer 34 Heating layer 40 Groove entry section 43 Ditch Crossing 50 Foam molding mold

Claims

1. In a seat pad having a sheet-shaped heater fixed to the pad body, The sheet heater is a sheet pad formed by laminating an electrode layer having a wiring pattern with a self-temperature regulating function and a heat generating layer on a stretchable base sheet.

2. In a seat pad having a sheet-shaped heater fixed to the pad body, The sheet heater is a sheet pad formed by laminating an electrode layer made of a wiring pattern having a self-temperature regulating function and a heat generating layer having a self-temperature regulating function on a stretchable base sheet.

3. The sheet heater is formed by laminating an electrode layer having a wiring pattern with a self-temperature regulating function and a stretchable heat generating layer on a stretchable base sheet.

4. A sheet heater comprising an elastic base sheet, an electrode layer consisting of a wiring pattern with a self-temperature regulating function, and a heat generating layer with a self-temperature regulating function laminated thereon.

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