JP2010131970A - Cloth material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cloth material which serves as an electrode of electrostatic capacity type sensor and can easily be connected with a cable for voltage application or the like. <P>SOLUTION: In the cloth material 10 prepared by laminating a surface material 30, a pad material 40 and a back base cloth 50 in this order, the back base cloth 50 is made conductible by a conductivity-imparting means such that the back base cloth can be used as the electrode of electrostatic capacity type sensor or a heater. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cloth material that can be used as an electrode or a heater of a capacitive sensor.

Conventionally, a configuration in which this type of capacitive sensor is disposed on a vehicle seat is known (see Patent Document 1).
The vehicle seat of Patent Document 1 includes an electrode unit embedded in a seat cushion seat portion, voltage applying means for applying a voltage to the electrode unit, and a seat frame for electrically connecting the electrode unit and the vehicle. When the passenger sits on the seat cushion, the electrode unit is electrically connected to the vehicle via the passenger (condenser), and an electric circuit is formed between the electrode unit, the passenger, and the seat frame. By detecting the current flowing in the electric circuit, the occupant on the seat cushion is discriminated (detected), and an operation such as deploying the airbag is performed as necessary.

And in the said structure, the electrode unit separate from a seat cushion is embed | buried under a seating part. However, when the seating feeling of the seat is taken into consideration, it is difficult to adopt a configuration in which the electrode unit that causes a foreign body feeling is arranged in the seating portion.
Therefore, Patent Documents 2 to 4 propose a technique in which the cloth material itself is made conductive to form an electrode. For example, Patent Document 2 discloses a technique for forming a woven fabric (cloth material) with warps and wefts in which metal fibers are exclusively covered with non-conductive fibers. Patent Document 3 discloses a fabric (cloth material) in which conductive yarns formed by metal plating are woven. Patent Document 4 discloses a cloth material in which a metal film and a resin layer containing a conductive filler are overlaid.
These known conductive cloth materials (skin materials) can be used as electrodes of a capacitive sensor without causing a passenger to feel as much foreign matter as possible.

Japanese Patent Laid-Open No. 2006-292631 JP 2006-234716 A Japanese Patent Laid-Open No. 2000-219076 JP 2003-266599 A

By the way, when a cloth material is used for the skin material of the vehicle seat, a pad material and a back base cloth may be disposed on the back surface of the cloth material in consideration of the seating property of the occupant. These members are typically integrated by a joining method such as laminating (the cloth material has a three-layer structure).
Then, while covering the seat cushion or the like with the cloth material, the cable extending from the voltage applying means built in the seat is connected to the back surface of the cloth material. At this time, the pad material and the back base cloth become an obstacle. For this reason, in the known technique, it is necessary to remove the pad material and the back base fabric that are integrated with the cloth material, and the connection work of the cable to the cloth material is unexpectedly troublesome.
The present invention has been devised in view of the above points, and the problem to be solved by the present invention is to connect a cable for applying a voltage to a cloth material that is an electrode or a heater of a capacitive sensor. It is to make it easy.

As a means for solving the above-mentioned problems, the cloth material of the first invention is formed by laminating a front material, a pad material and a back base fabric in this order, and is made conductive by a conductive means, and is a capacitance type. It is the structure which can be used as an electrode or a heater of a sensor.
In this type of cloth material, for example, when used as a skin material for a vehicle seat, it is desirable that a cable for applying voltage or the like be easily connected.
Therefore, in the present invention, the back base cloth of the cloth material is made conductive by the conductive means so that it can be used as an electrode or a heater of the capacitive sensor. With this configuration, when connecting a cable for voltage application from the back side of the cloth material, connect directly to the cloth material (back base cloth) without removing the surface material or pad material. Can do.

  According to the first aspect of the present invention, a cable for applying voltage or the like can be more easily connected to a cloth material that is an electrode or a heater of a capacitance type sensor.

It is a partial see-through side view of a vehicle seat. It is a longitudinal section showing an exploded seat cushion. (A) And (b) is a front view of a cloth material. It is a circuit diagram of an object detection system. It is a graph for measuring an electrostatic capacitance. It is the schematic of the system which operates an object detection system and an airbag. It is a front view of the cloth material of another example. It is a longitudinal cross-sectional view of the cloth material of Embodiment 2.

Hereinafter, embodiments for carrying out the present invention will be described with reference to FIGS. In FIG. 3, for convenience, only some of the conductive yarns are denoted by reference numerals. In FIG. 7, conductive carbon is indicated by dots.
The cloth material 10 of each embodiment is a skin material 4S (one example) of the vehicle seat 2 and constitutes a part of the object detection device as will be described later with reference to FIG. That is, the cloth material 10 itself as the skin material 4S is used as an electrode (an example of an application) of a capacitive sensor that determines the occupant H (object) on the seat.
And in this kind of skin material 4S, it is desirable that the cable for voltage provision etc. is easy to connect. Therefore, in each embodiment, the cloth material 10 can be used as an electrode of a capacitive sensor by making a back base cloth 50 described later conductive.

[Embodiment 1]
In the present embodiment, a conductive means (an example) having conductive yarns 12 will be described with reference to FIGS. And, as will be described later, the back base fabric 50 is configured with the conductive yarns 12 to ensure cable connectivity. Hereinafter, each configuration will be described in detail.

(Basic composition of cloth material)
Referring to FIG. 2, the fabric material 10 includes a front material 30, a pad material 40, and a back base fabric 50.
The surface material 30 is a member constituting the seating side of the surface material 4S (cloth material 10). For example, a cloth (woven fabric, knitted fabric, non-woven fabric or composite thereof) made of insulating fibers described later, natural leather or artificial leather. Consists of.
The pad material 40 is a cushion member that ensures the seating ability of the occupant H, and is composed of, for example, a slab urethane foam made of a soft urethane foam.

(Back fabric)
And the back base fabric 50 is a member which comprises the back side (side different from the seating side) of the skin material 4S (cloth material 10). The back base fabric 50 is also a member that covers the pad material 40 to ensure the smoothness (slidability) of the skin material 4S at the time of sewing and covering the sheet.
In the present embodiment, a part or all of the back base fabric 50 is constituted by the conductive yarn 12 described later.

(Conductive yarn)
The type of the conductive yarn 12 is not particularly limited, but copper sulfide-bonded conductive yarn, carbon-based conductive yarn, carbonaceous fiber, graphite fiber, metal or alloy plating yarn (insulating fiber having a plating layer), metal Examples thereof include fibers, carbon nanotubes, and carbon nanotube coating yarns.
Among these, copper sulfide-bonded conductive yarns, carbon nanotube coating yarns and plated yarns have excellent sliding properties, so they function as backing fabrics (component yarns) and are less conductive over time due to chemical changes. Are better.
Furthermore, since the copper sulfide-bonded conductive yarn, the carbon nanotube coating yarn and the plating yarn have better stretchability than the stainless fiber, they do not hinder the stretchability of the skin material 4S.

  JP-A-2-145864 discloses a resin layer containing activated carbon. However, the conductive means having a large electric resistance (specific resistance, resistance value, or resistivity) is exclusively for preventing charging, and the conductive material 10 (back base) that can be used as an electrode of the capacitance type sensor is used. It cannot be applied to the cloth 50).

Here, the conductive yarn 12 preferably has a specific resistance (also referred to as volume resistivity) of 10 ⁰ to 10 ⁻¹² Ω · cm. By attaching the conductive yarn 12 to the back base fabric 50, the skin material 4S can be used as an electrode of a capacitance sensor. Moreover, when using the back base fabric 50 as a heater (other uses) mentioned later, it is desirable that the specific resistance of the conductive yarn 12 is 10 ⁻¹ to 10 ⁻⁵ Ω · cm.
Here, the “specific resistance (volume resistivity)” is a physical property value used for comparing what kind of material is difficult to conduct electricity, and is measured in accordance with, for example, “JIS K-7194”. Can do.

Furthermore, it is desirable to use the conductive yarn 12 having a resistance value of 0.1 to 5 × 10 ⁶ Ω per 10 cm as the conductive yarn 12.
Here, the “resistance value per 10 cm” is a resistance value between the conductive yarns 10 cm when a low voltage of about 5 V is applied, and is measured using a general-purpose tester (maximum resistance measurement value is about 60 MΩ). can do. In addition, since a capacitance type sensor is typically used with weak electricity, evaluation at a high voltage for the purpose of preventing charging is not appropriate.

Thus, by setting the resistance value of the conductive yarn 12 to 0.1 to 5 × 10 ⁶ Ω, the conductive cloth material 10 (back base cloth 50) can be used as an electrode of the capacitance sensor. It becomes. Here, if the resistance value per 10 cm of the conductive yarn 12 is larger than 5 × 10 ⁶ Ω, the cloth material 10 (back base cloth 50) is not sufficiently conductive, and used as an electrode of a capacitive sensor. I can't.
A preferable conductive yarn 12 is a conductive yarn having a resistance value of 0.1 to 4.0 × 10 ⁶ Ω per 10 cm. The cloth material 10 (back base cloth 50) made conductive by the conductive yarn 12 can be suitably used as an electrode of a capacitance sensor. A more preferable conductive yarn 12 is a conductive yarn having a resistance value of 0.1 to 3.0 × 10 ⁶ Ω per 10 cm. The cloth material 10 (back base cloth 50) made conductive by the conductive yarn 12 exhibits a sensor function (having a capacitance) comparable to the cloth material 10 made conductive by stainless steel fibers.

The carbon-based conductive yarn is a conductive yarn in which carbon black is contained in a fiber (typically an insulating fiber) such as nylon fiber or polyester fiber.
In this carbon-based conductive yarn, a desired resistance value is imparted by appropriately adjusting the carbon black content of the fiber. At this time, a configuration in which part of the fiber cross section is cut out and kneaded with carbon black may be used, or a structure in which the outer periphery of the fiber cross section is coated with a polymer in which carbon black is kneaded may be used.
For example, “Megana RN (registered trademark)” manufactured by Unitika Fiber Co., Ltd. is a conductive yarn (33 dtex, 4 filaments) coated with carbon black on the outer periphery of the fiber cross section, and the resistance value per 10 cm is 3 × 10 ⁶ Ω. It is.

The copper sulfide-bonded conductive yarn is a conductive yarn in which copper sulfide is bonded to a fiber such as nylon fiber or acrylic fiber. In this copper sulfide-bonded conductive yarn, a desired resistance value is imparted by appropriately adjusting the amount of copper sulfide bonded to the fiber (see Japanese Patent Application Laid-Open No. 56-169808).
For example, “Sunderron (registered trademark)” manufactured by Nippon Kashiwa Co., Ltd. is a conductive yarn (110 dtex, 24 filaments) in which copper sulfide is bonded to a polymer, and the resistance value per 10 cm is 1.5 × 10 ⁴ Ω. is there.

The carbon nanotube coating yarn is a conductive yarn in which carbon nanotubes are coated on the surface of a constituent filament (for example, a filament of an insulating fiber).
The resistance value per 10 cm of the carbon nanotube coating yarn can be controlled by appropriately adjusting the type of carbon nanotube and the coating amount thereof. For example, “CNTEC” manufactured by Kuraray Living Co., Ltd. can control the resistance value per 10 cm to 10 ³ to 10 ⁶ .

(Conducting the back base fabric)
The following method can be illustrated as a method for making the back base fabric 50 conductive.
(A) After all or most of the back base fabric 50 is made of insulating fibers, the back base fabric 50 is made conductive.
(B) The back base fabric 50 is produced using the conductive yarn 12 or insulating fibers that have been made conductive in advance.
(C) A part of the back base fabric 50 made of insulating fibers is constituted by the conductive yarns 12 or insulating fibers that have been made conductive in advance.

As the method (a), for example, a method of making insulating fibers conductive by attaching and bonding copper sulfide to the backing base fabric 50 can be exemplified (see Japanese Patent Laid-Open No. 56-169808). Further, by making the insulating fiber conductive using supercriticality, it is possible to conduct the conductive material while minimizing the change in the texture of the back base fabric 50 (see JP 2005-264395 A).
According to the above-mentioned method, since the existing equipment for producing the back base fabric 50 can be used, it is preferable in terms of the production cost of the back base fabric 50.

Moreover, as a method of (a), it can be made conductive by forming a plating layer of metal or alloy on the back base fabric 50.
The method for forming the plating layer is not particularly limited. For example, after the back base fabric 50 is made of insulating fibers, a plating layer can be formed on the back base fabric 50 by electroless plating. Moreover, after producing the back base fabric 50 which has a metal in part, a plating layer can be formed in the back base fabric 50 by an electroless plating process or an electroplating process.
The metal or alloy used for the plating process is not particularly limited, but nickel (Ni), cobalt (Co), copper (Cu), silver (Ag), tin (Sn), gold (Au), iron (Fe), lead (Pb), platinum (Pt), zinc (Zn), chromium (Cr) and palladium (Pd) can be exemplified. Examples of the alloy used for the plating process include Ni—Sn, Cu—Ni, Cu—Sn, Cu—Sn, Cu—Zn, and Fe—Ni.
The above-described plated yarn (an example of a conductive yarn) can also be manufactured by a similar method.

In the above-described method, various coatings (such as an abrasion-resistant coating, a lubricous coating, and a corrosion-resistant coating) can be formed on the back base fabric 50 simultaneously with the plating process.
For example, during the plating process, silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), boron carbide (B ₄ C), diamond, and the like are co-deposited (composite plating is performed) so that the wear-resistant coating can be backed. It can be formed on the base fabric 50.
In addition, a lubricating coating can be formed on the back base fabric 50 by co-depositing Teflon (registered trademark) (PTFE) or graphite fluoride.
In addition, by co-depositing silicon carbide + boron nitride (BN), silicon nitride (Si ₃ N ₄ ) + boron nitride, silicon nitride + calcium fluoride (CaF ₂ ), etc. It can be formed on the base fabric 50.
And a corrosion-resistant film can be formed in the back base fabric 50 by co-depositing metal fine powders, such as cobalt (Co), molybdenum (Mo), tungsten (W), and titanium (Ti).

Furthermore, as a technique of the above (a), the insulating fiber can be made conductive by carbon nanotube coating. For example, according to Japanese Patent Application Laid-Open No. 2008-201635, the insulating fiber and the backing base fabric 50 can be coated with carbon nanotubes.
Incidentally, the carbon nanotube coating has a drawback that it is relatively easy to fall off. Therefore, in this embodiment, the coating can be stably held on the back base fabric 50 by applying the same coating to the back base fabric 50 to avoid friction with the occupant (the conductivity of the back base fabric 50 is improved). Can be maintained stably). Further, since the back base fabric 50 is integrated with the pad material 40 (urethane foam), the coating hardly falls off due to the friction between the back base fabric 50 and the pad material 40.
In addition, by forming a resin layer (resin layer as a protective layer) separately on the back base fabric 50, the coating can be more stably held on the back base fabric 50.

  In addition, the back base fabric 50 applicable to said (a) etc. is the cloth (woven fabric, a nonwoven fabric, or these composites) comprised only with the insulating fiber. Here, the back base fabric 50 may be a woven fabric having any structure such as a plain woven fabric, an oblique woven fabric, or a satin woven fabric, and may be a knitted fabric having any structure such as warp knitting, circular knitting, or flat knitting. The structure of the knitted fabric may be either horizontal knitting or vertical knitting. The backing fabric 50 may be a nonwoven fabric produced by any fiber (raw material), any web forming technique, or any web bonding technique.

The insulating fiber is, for example, a material having a specific resistance exceeding 10 ⁸ Ω · cm, and examples include plant-based and animal-based natural fibers, chemical fibers made of thermoplastic resin or thermosetting resin, and blended fibers thereof. can do.
And in natural fiber, since cotton, hemp, or wool is excellent in a texture, it is preferable to use as a structure of the back base fabric 50. FIG. Moreover, in the chemical fiber, since the polyester fiber and the nylon fiber are excellent in handleability, it is preferable to use as a structure of the back base fabric 50. In particular, a filament made of polyethylene terephthalate, polycaproamide, and polyhexamethylene didipamide is excellent in durability, light resistance, and strength.

Further, as the method (b), for example, the back base fabric 50 as a woven fabric or a knitted fabric can be produced by knitting or weaving the conductive yarn 12 (including plated yarn) or conductive insulating fibers. Examples of the conductive insulating fibers include insulating fibers to which copper sulfide is adhered and bonded, insulating fibers that are supercritically conductive, and insulating fibers that are coated with carbon nanotubes. At this time, by using a copper sulfide-bonded conductive yarn or a carbon-based conductive yarn, it is possible to fabricate the backing fabric 50 having various structures.
Moreover, the back base fabric 50 as a nonwoven fabric can also be produced using the conductive yarn 12 (long fiber or short fiber). The method for producing the nonwoven fabric may be either dry or wet.
A preferable back base fabric 50 is a fabric having moderate thinness and stretchability. The back base fabric 50 of woven fabric or knitted fabric is excellent in slipperiness with the pad material 40 and has a sitting comfort suitable as the skin material 4S of the vehicle seat 2. At this time, it is desirable that the back base fabric 50 has the same thinness and stretchability as the back base fabric 50 formed by knitting a nylon filament (18 tex) into a half tricot.

And as the method of (c), while producing the back base fabric 50 with an insulating fiber, the several conductive yarn 12 or the insulating fiber electrically conductive previously is arrange | positioned in parallel within the range of space | interval dimension (W1) 60mm. A technique can be exemplified. Then, the back base fabric 50 is made electrically conductive by electrically connecting a plurality of conductive yarns 12 and the like by energizing means 14 described later (see FIG. 3).
Specifically, when producing the woven fabric backing 50, a plurality of conductive yarns 12 and the like are introduced as wefts (warps). Further, when the back base fabric 50 of the knitted fabric is produced, the conductive yarn 12 or the like is introduced into a part of the course direction or the wale direction.
According to the above-described method, it can be used as an electrode of a capacitive sensor without impairing the original characteristics (smoothness, texture, feel, sitting comfort, breathability, durability) of the back base fabric 50 as much as possible. .

Here, if the spacing dimension (W1) of the conductive yarns 12 and the like exceeds 60 mm, the sensor function of the cloth material 10 (back base cloth 50) deteriorates (capacitance decreases), and the electrode of the capacitive sensor is used. May not function.
Preferably, the conductive fabric material 10 has a more suitable sensor function (capacitance) by setting the upper limit value of the distance dimension (W1) of the conductive yarns 12 and the like to 30 mm.
Further, the upper limit value of the preferable distance dimension (W1) is 25 mm, and the most preferable upper limit value is 20 mm. Thus, by setting the upper limit of the distance dimension (W1) to less than 30 mm, even if some of the conductive yarns 12 and the like are disconnected, the gap size between the conductive yarns located on both sides of the disconnected conductive yarns 12 and the like ( W2) is preferably maintained.
And even if the space | interval dimension (W1) of each electrically conductive thread | yarn 12 grade | etc., Is made smaller than 25 mm (narrow), the extreme improvement of the electrostatic capacitance of the back base fabric 50 is not seen. For this reason, in consideration of the cost of the cloth material 10, it is desirable that the lower limit of the interval dimension (W1) is 1 mm.
In addition, when giving the heater function to the cloth material 10 (back base cloth 50), the space | interval dimension (W1) of the conductive yarn 12 grade | etc., Can be set to 0 mm-60 mm. Here, when the entire surface of the back base fabric 50 is composed of the conductive yarn 12 or the like, the distance dimension (W1) becomes 0 mm.

The energizing means 14 is a conductive member that electrically connects the plurality of conductive yarns 12 and the like, and examples thereof include conductive yarns, metal wires, conductive tapes, conductive resin layers, conductive fabrics and films. it can. Further, examples of a method for electrically connecting the plurality of conductive yarns 12 and the energizing means 14 (excluding the conductive resin layer) include pressure bonding by sewing and sewing by conductive yarn or metal wire. The energizing means 14 may be formed on a part of the back surface of the back base fabric 50, or may be formed on the entire back surface of the back base fabric 50.
For example, referring to FIG. 3A, the conductive tape 14a is stuck in the warp direction so as to connect a plurality of conductive threads 12 and the like (wefts). In addition, it is desirable that the width dimension of the conductive tape is 1 mm or more from the viewpoint of securing the connection stability of the conductive yarn 12 and the like.

Here, when the back base fabric 50 is used as a heater (details will be described later), the specific resistance of the energizing means 14 is based on the specific resistance of various conductive means (conductive yarn 12, conductive insulating fiber, back base cloth 50, etc.). Is preferably low. By making the specific resistance of the energizing means 14 lower than that of the conducting means, heat generation of the energizing means 14 during energization can be prevented or reduced.
The specific resistance of the energizing means 14 can be appropriately set according to the specific resistance of the conducting means. Typically, by setting the range of the specific resistance of the energization means 14 to 1.4 to 15 × 10 ⁻⁸ Ω · m, heat generation of the energization means 14 during energization can be suitably prevented or reduced. .

Moreover, the electrically conductive resin layer can also be used as the electricity supply means 14 (the detailed structure of the resin layer will be described in Embodiment 2).
For example, referring to FIG. 3B, a conductive resin layer 14b is formed in the warp direction so that a plurality of conductive yarns 12 and the like (wefts) are electrically connected. The conductive resin layer 14b is relatively strongly integrated with the back base fabric 50, and has a configuration with good connection stability (hard to break).
The conductive resin layer 14b preferably contains an inorganic conductive agent so that the resistivity of the coating surface is 1 to 5 × 10 ³ Ω · cm. By doing so, the plurality of conductive yarns 12 can be electrically connected. Here, the inorganic conductive agent is, for example, fine particles of carbon black, fine particles of metal oxide such as conductive tin oxide (ATO) or indium tin oxide (ITO).

And after laminating | stacking the surface material 30, the pad material 40, and the back base fabric 50 in this order, it integrates with a joining means and the fabric material 10 is produced. Examples of the joining means include methods such as laminating (welding), sewing, and adhesion. Of these, laminating is preferable because the constituent elements of the fabric material 10 can be more reliably integrated.
When the conductive back base fabric 50 is used as an electrode of the capacitance sensor, the back base fabric 50 made conductive by the above-described method (a) or (b) has a part of the back base fabric 50 and the voltage applying means 15. By connecting, the entire back base fabric 50 can be energized. Therefore, by connecting the cable 16 (terminal 16a) to the back base cloth 50 by caulking or the like (with a relatively simple connection method), the back base cloth 50 can function as an electrode of the capacitance type sensor.
In addition, when using the electrically conductive back base fabric 50 as a heater, it is preferable to connect the electricity supply means 14 to the both ends of the fiber arrangement direction, respectively, regardless of the methods (a) to (c) (described later).

[Object detection system]
With reference to FIG.1 and FIG.6, the structure of the object detection system using the above-mentioned cloth material 10 is explained in full detail. The object detection system is applied to a vehicle seat 2 including a seat cushion 4, a seat back 6, and an airbag 8.
The object detection system includes a skin material 4S (cloth material 10) of the seat cushion 4, a voltage application unit 15, a seat frame F (electrode member), and a measurement circuit 18 (detection unit).
Seat frame F is grounded to the vehicle compartment floor, a member constituting the first capacitor C ₁ with the skin material 4S. The voltage applying means 15 is a member that applies a voltage to the skin material 4 </ b> S, and is built in the seat cushion 4.

With reference to FIG. 2, the skin material 4 </ b> S of the present embodiment is configured by sewing a plurality of cloth materials 10 into a bag shape. After covering the pad member 4P of the seat cushion 4 with the skin material 4S, the sewn portion between the cloth materials 10 is attached to the groove portion 4C of the pad member 4P in a retracted manner.
And the cable 16 (terminal 16a) extended from the voltage provision means 15 is connected to the skin material 4S back surface side through the pad member 4P through hole (not shown). At this time, in the present embodiment, the back base fabric 50 on the back surface of the cloth material 10 is made conductive. For this reason, when connecting the cable 16 for voltage application from the back side of the cloth material, it can be directly connected to the cloth material 10 (back base cloth 50) without removing the pad material 40 and the like. By thus connecting the cable 16 to the skin material 4S (caulked), (first through the capacitor C ₁₎ an electrical circuit is formed between the seat frame F skin material 4S (fabric material 10) .
Furthermore, in this system, the occupant H, which is a kind of conductor, is arranged on the skin material 4S so that another electric circuit is formed through the second capacitor (occupant H) (see FIG. 1). ). Thus, in the present embodiment, the skin material 4S (cloth material 10) itself functions as an electrode of the capacitive sensor.

Here, with reference to FIG.4 and FIG.5, the measuring method (an example) of the electrostatic capacitance using the said system is demonstrated.
A DC voltage is applied to the end V ₁ of the cable 16 by the voltage applying means 15. Then, a time T required to reach the specified voltage V ₀ at an arbitrary position V ₂ in the middle of the cable 16 is measured.
And when the vehicle seat 2 is vacant time T of the (first when only the capacitor C ₁ is formed) and t _1. Also when the occupant H is seated on the vehicle seat 2 time T (when the first capacitor C ₁ and the second capacitor C ₂ is formed) and t _2. This sitting time T (t ₂ ) is longer than the vacant time T (t ₁ ).
By measuring the time difference (capacitance difference) between t ₂ and t ₁ with the measurement circuit 18, the occupant H on the skin material 4S can be determined.
In the above description, the configuration of the capacitive sensor using a DC circuit has been exemplified. However, the back base fabric 50 of the present embodiment is also preferably used as an electrode of a capacitive sensor using an AC circuit. Yes (see JP 2007-240515).

Referring to FIG. 6, after determining the occupant H by the vehicle seat 2 (object detection system), the ECU (19) of the vehicle seat deploys the airbag 8 as necessary. By setting it as such a structure, the airbag 8 can be expand | deployed only to the vehicle seat 2 on which the passenger | crew H sits (refer FIG. 1). Further, the ECU (19) of the vehicle seat turns on the display lamp 9 to urge the passenger to wear the seat belt (warning).
By the way, in the case of a child with a small passenger H (for example, an infant under 1 year old), it may be better not to deploy the airbag 8 for safety (see US automobile safety standard FMVSS208). In this exemplary embodiment, if the infant (small infant physique than adults) is seated, a configuration in which the capacitance of the second capacitor C ₂ is reduced. For this reason, in the vehicle seat 2 (object detection system), when the baby is seated (when the capacitance is relatively low), the airbag 8 can be set not to deploy.

[Another example]
The skin material 4S (cloth material 10) can be used as a heater.
For example, referring to FIG. 7, energizing means 14 (band-like) is arranged at both ends of cloth material 10. Then, the terminals of the power cable 9 a are connected to the energizing means 14, and the power supply member 29 (for example, in-vehicle power supply) and the conductive yarn 12 are electrically connected to form an electric circuit of the plurality of conductive yarns 12 on the cloth material 10. At this time, the energizing means 14 is sewn to the cloth material 10 so that the relative positional relationship between the two is suitably maintained (the electrical connection stability of the energizing means 14 and the conductive yarn 12 and the like is improved).
And the skin material 4S can be used as a heater by applying electric power to the conductive yarn 12 arranged between the pair of energizing means 14 (heating area) to generate heat. At this time, in this embodiment, the plurality of conductive yarns 12 can be heated at a relatively low voltage by forming a parallel circuit of the plurality of conductive yarns 12 by the pair of energizing means 14.
In the present embodiment, the thinner the pad material 40 is, the faster the heat is transmitted. Therefore, the thickness of the pad material 40 is preferably set to about 1 to 5 mm.

Thus, in this embodiment, when connecting the cable 16 for voltage application from the back side of the skin material 4S (cloth material 10), it connects directly to the back base fabric 50 without removing the pad material 40 and the like. can do.
For this reason, according to this embodiment, the cable 16 for voltage provision etc. can be more easily connected to the skin material 4S (cloth material 10) which is an electrode of an electrostatic capacitance type sensor.
Moreover, in this embodiment, it is the structure which makes the back base fabric 50 electrically conductive, and the surface material 30 which comprises a seating side is a structure which is not electrically conductive. For this reason, the original characteristics (designability, texture, touch, sitting comfort, breathability, durability) of the surface material 30 are not lost as much as possible.
Furthermore, the back base fabric 50 is disposed at a position close to the occupant and can take a relatively large electrode area (detection area). For this reason, according to the present Example, a capacitive sensor with high sensor sensitivity can be constructed in a vehicle seat (a sensor particularly suitable for a vehicle seat can be constructed).

[Embodiment 2]
Since the basic structure of the second embodiment is substantially the same as the basic structure of the first embodiment, the same reference numerals are assigned to the common structures and the detailed description is omitted.
In this embodiment, referring to FIG. 8, a conductive means (another example) configured with a conductive resin layer 20 will be described. The resin layer 20 is typically formed after the cloth material 10 is laminated.

(Resin layer)
The resin layer 20 of the present embodiment is a resin layer that is made conductive by containing the above-described inorganic conductive agent. The resin layer 20 may be energized, but it contains conductive carbon so that the coating surface has a resistivity of 1 to 5 × 10 ³ Ω · cm. It is desirable to be formed.
Here, the “resistivity” is an electrical resistivity measured according to “JIS K 7194 (1994)”.
Examples of the conductive carbon include carbon black fine particles (amorphous carbon) such as ketjen black, channel black, acetylene black, thermal black, furnace black, and lamp black, and carbon nanotubes. Among them, ketjen black fine particles and carbon nanotubes are excellent in conductivity, and can be suitably used as the structure of the resin layer 20.

The resin constituting the resin layer 20 is a thermosetting resin or a thermoplastic resin that is cured by heat or drying and can be bonded to the cloth material 10.
Examples of the thermoplastic resin include acrylic resin, polyethylene resin, polypropylene resin, fluororesin, vinyl chloride resin, vinyl acetate resin, polyvinylidene chloride resin, and polyimide resin. Examples of the thermosetting resin include urethane resin, silicon resin, epoxy resin, phenol resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, and thermosetting polyimide resin.
Among these, acrylic resin is excellent in durability and light resistance, and therefore it is desirable to use it as a configuration of the resin layer 20.

Then, by setting the resistivity of the coating surface of the resin layer 20 to 1 to 5 × 10 ³ Ω · cm, the cloth material 10 (the back base fabric 50) made conductive by the resin layer 20 is used for the capacitance type sensor. It can be used as an electrode.
Here, if the resistivity of the resin layer 20 is greater than 5 × 10 ³ Ω · cm, the cloth material 10 is not sufficiently conductive and cannot be used as an electrode of a capacitive sensor.
A preferred resin layer 20 is a resin layer having a coating surface resistivity of 1 to 1 × 10 ³ Ω · cm. The cloth material 10 made conductive by the resin layer 20 can be suitably used as an electrode of a capacitive sensor. A more preferable resin layer 20 is a resin layer having a coating surface resistivity of 10 to 40 Ω · cm. The cloth material 10 made conductive by the resin layer 20 exhibits a sensor function comparable to the cloth material 10 made conductive by stainless steel fibers (has a capacitance).

(Formation of resin layer)
Conductive carbon and resin are dispersed in a predetermined solvent to prepare a resin composition (backing agent). The content of the conductive carbon is desirably 3% by weight to 30% by weight with respect to the total solid content of the backing agent. The solvent in the solvent is a solvent capable of dispersing the conductive carbon and the resin, and typically an aqueous solvent or an organic solvent is used.

And after giving a backing agent to all or a part of cloth material 10 back side, resin layer 20 is formed by heating or drying. The amount of backing agent applied to the cloth material 10 is set to, for example, 30 to 200 g / cm ² depending on the content of conductive carbon.

  The coating method is not limited, and in addition to coating with a coating machine, coating by printing such as letterpress printing, intaglio printing, stencil printing with plate printing, and ink jet printing without plate printing is exemplified. . Among the prints, gravure rolls and rotary screen printing are preferably used.

  And the resin layer 20 of this embodiment may be formed in the whole surface of the fabric material 10 back, and may be formed in a part of cloth material 10 back surface. For example, the plurality of resin layers 20 may be formed in parallel within a range of a spacing dimension of 60 mm like a conductive yarn, may be formed in a mesh shape (cross shape, lattice shape), or may be formed concentrically. May be. At this time, the stretchability, softness, and smoothness of the back base fabric 50 can be maintained by making the resin layer 20 mesh.

And the fabric material 10 of this embodiment can be used as the skin material 4S of the seat cushion 4 similarly to Embodiment 1 (refer FIG. 1). The resin layer 20 is formed on the back base fabric 50. For this reason, when connecting the cable 16 for voltage application from the back surface side of the skin material 4S (cloth material 10), it can be directly connected to the back base fabric 50 without removing the pad material 40 and the like.
For this reason, according to the present embodiment, the cable 16 for applying voltage can be more easily connected to the skin material 4S (cloth material 10) which is an electrode of the capacitive sensor.
Also in this embodiment, the back base fabric 50 is configured to be conductive, and the surface material 30 constituting the seating side is not configured to be conductive. For this reason, the original characteristic of the surface material 30 is not lost as much as possible.

Hereinafter, although this embodiment is described based on an example, the present invention is not limited to an example.
[Example 1]
In Example 1, a double jersey front material, a pad material of a frame urethane sheet (EL67F, manufactured by INOAC), and a half tricot back base fabric made of copper sulfide-bonded conductive yarns were used.
The surface material was produced using a weaving machine (gauge 30G, 48 yarn feeds, 1862 needles, 30 inch hook diameter) from Fukuhara Seiki Co., Ltd. At this time, a front yarn of polyester-based false twisted yarn dyed yarn (167 dtex / 2-48 filament) and a back yarn of polyester-based false twisted yarn dyed yarn (334 dtex-72 filament) were used. And the surface material was produced by performing finishing processing (scouring 98 degreeC * 30min, finishing set 180 degreeC). The finishing density of the surface material was a course density of 25 / 2.54 cm and a wale density of 29 / 2.54 cm.

The back base fabric used was a half tricot made of copper sulfide dispersed and adsorbed to make it conductive (the method for making the conductivity will be described later). The half tricot was knitted with a multifilament of polycaproamide (18 dtex-3 filament) (weighing 53 g / m ² ). Then, when the knitted fabric of the back base fabric was disassembled and the resistance value of the yarn was measured, the resistance value per 10 cm was 1.2 × 10 ⁴ Ω.
And after laminating the front material, the frame urethane sheet and the back base fabric in this order, they were integrated by laminating. As a result, the thickness of the frame urethane sheet portion was 5 mm.

Here, the conductive method of the first embodiment will be described.
After washing the above-mentioned half tricot with hot water at 50 ° C. to remove the oil agent, 50% by weight of acrylonitrile, 1.2% by weight of ammonium persulfate and 3% by weight of sodium hydrogen sulfite with respect to the weight of the half tricot In an aqueous solution with a bath ratio of 1:20 and treated at 70 ° C. for 60 minutes while gradually warming from room temperature. Thereafter, it was washed thoroughly with hot water and water to sufficiently remove unreacted substances, side reaction products and catalyst.
Next, the washed half tricot is placed in an aqueous solution having a bath ratio of 1:20 containing 10% by weight cupric sulfate, 10% by weight sodium thiosulfate and 5% by weight sodium bisulfite based on the fiber weight. The mixture was treated at 100 ° C. for 60 minutes while gradually raising the temperature from room temperature. Thereafter, it was washed with water and dried. In this way, copper sulfide was dispersed and adsorbed on the half tricot to make it conductive.

[Example 2]
In Example 2, a cloth material in which the surface material and the pad material of Example 1 and the half tricot of Example 1 were laminated in this order was used. The cloth material previously laminated was made conductive with a resin layer described later.

Here, a method for forming the resin layer of Example 2 will be described.
As a backing agent, 27% acrylic polymer synthesized from butyl acrylate and acrylonitrile as a solid content, 67% flame retardant, other backing agent containing foaming agent and foam stabilizer, Lion paste W-310A (inner carbon black 13.7) %) Was prepared by dispersing the carbon black concentration in the solid content to be 10% by weight.
The backing agent was printed on the back of the back base fabric using a flat screen and then dried at 150 ° C. The coating amount of the backing agent was 60 g / m ² . A resin layer having a lattice pattern (2 mm width × 5.5 mm interval) and inclined by 45 ° with respect to the course direction was formed on the back base fabric. The resistivity of the coating surface of the resin layer was 26 Ω · cm.

[Example 3]
In the fabric material of Example 3, the front material and the pad material (frame urethane sheet) of Example 1 and the back base fabric (described later) on which a plating layer was formed were used. And after laminating | stacking a surface material, a pad material, and a back base fabric (after-mentioned) in this order, it integrated by the lamination process. The thickness of the frame urethane sheet portion was 5 mm.
A circular knitting (16 gauge, density W / C = 27/31 pieces / 2.54 cm, basis weight 53 g / m ² ) composed of polyester filaments (84 dtex-36 filaments) was used as the back base fabric of this example. . Next, a metal film (plating layer) by the following plating treatment and a resin layer by a cationic electrodeposition coating method were formed on the back base fabric (see Example 1 of JP-A-11-346089).

(Plating treatment)
After performing scouring presetting on the above-mentioned backing base fabric, a weight reduction treatment of 20% was performed by alkaline hydrolysis, and a copper and nickel metal coating was formed by an electroless plating method. After the formation of the metal film, about 40 g / m ² by a cationic electrodeposition coating method (electrodeposition condition bath temperature 20 ° C., voltage 50 V, energization time 30 seconds) using a thermosetting amino group-containing acrylic cationic electrodeposition resin. A transparent resin layer having a thickness of about 5 μm was formed. Next, preliminary drying (100 ° C., 10 minutes) and baking (145 ° C., 30 minutes) were performed to obtain the desired back base fabric of Example 3.
When the knitted fabric of the back base fabric of this example was disassembled and the resistance value of the yarn was measured, the resistance value per 10 cm was 81Ω.

[Example 4]
In the fabric material of Example 4, the front material and the pad material (frame urethane sheet) of Example 1 and the back base fabric (described later) coated with carbon nanotubes were used. And after laminating | stacking a surface material, a pad material, and a back base fabric (after-mentioned) in this order, it integrated by the lamination process. The thickness of the frame urethane sheet portion was 5 mm.
In this example, the carbon nanotube coating was applied to the back base fabric of Example 1 by the following method (see claim 24 of JP 2008-201635 A). Furthermore, in this example, according to a conventional method, the acrylic resin was thinly coated on the coating to prevent the carbon nanotubes from falling off the back base fabric.

(Carbon nanotube coating)
In this example, a minute carbon (nano to micro-sized fine carbon) and a dispersant (an amphoteric molecule having both electron ion pairs) are dispersed in a liquid solvent (aqueous solvent or non-aqueous solvent) in a monomolecular state. A carbon dispersion was used. This fine carbon dispersion was spread on the water surface, and the fine carbon monomolecular film spread on the water surface was transferred to the back base fabric. Then, the back base fabric was dried to form a fine carbon monomolecular film on the back base fabric.
When the knitted fabric of the back base fabric of this example was disassembled and the resistance value of the yarn was measured, the resistance value per 10 cm was 1.3 × 10 ³ Ω.

[Test method]
(Resistance value of conductive yarn)
The resistance value (Ω) of the conductive yarn according to Examples 1, 3, and 4 was measured using a tester (Digital Tester CDM-6000, manufactured by Custom Inc.).
After measuring the resistance value between 10 cm of the conductive yarns at five random points, the average value of the resistance values at the five points was taken as the resistance value per 10 cm of the conductive yarn.

(Resistivity of resin layer)
The resistivity (Ω · cm) of the resin layer according to Example 2 was measured according to “JIS K 7194 (1994)”. ASP (5 mm between pins) was used as a pickup with a low resistivity meter (LORESTA-GP MCP-T600, manufactured by Mitsubishi Chemical Corporation).
More specifically, a sample piece (length 80 mm × width 50 mm) was cut out from the cloth material of Example 2. And the limiter voltage was set to 10V and the sample piece was measured at one point.

(Capacitance)
Using the vehicle seat of FIG. 1 and the circuit of FIG. 4, “capacitance when empty” and “capacitance when sitting” of the cloth materials according to Examples 1 and 2 were measured.
After cutting a sample piece (40 cm square) from the cloth material of each example, the sample piece was placed on the seat cushion. The upper end of the sample piece was placed at the boundary between the seat cushion and the seat back. And the sample piece was always installed in the same position of the sheet by arranging the center line of the sheet and the center line of the sample piece. The seat frame or the occupant was grounded by an iron plate placed on the floor of the passenger compartment.
Then, when the seat is empty, a DC voltage of 5 V is applied from the end V ₁ of the cable, and the time T until the position V _{2 in the} middle of the cable reaches the specified voltage (3.3 V) is measured (R ₁ is 470 kΩ) did). And after the V ₂ reaches a predetermined voltage, and once discharge the respective capacitors, and repeats the same measurement. An average of the obtained values was taken as the “capacitance when empty” of the sample piece. Similarly, at the time of sitting, the time T until V ₂ reaches the specified voltage (3.3 V) was measured to obtain the “capacitance at the time of sitting” of the sample piece.
The “capacitance at the time of vacant seat” and “capacitance at the time of seating” of the sample piece were calculated from the time difference of time T (t ₁ , t ₂ ) at which V ₂ becomes the specified voltage.

(Amount of backing agent applied)
(A) In order to measure the fabric weight (g / m ² ) of the cloth material to be used, a 1 m square was cut out and measured in advance.
(B) After coating and drying, it was confirmed that the density before coating was unchanged. In the applied part, 5 points and 20 cm squares were cut out at random and the basis weight was measured.
(C) The coating amount was obtained from the difference between the basis weight before coating and after coating.
[Amount of application (g / m ² )] = [Amount of basis weight after application (g / m ² )] − [Amount of basis weight before application (g / m ² )]

[Test results and discussion]
The results of each test are shown in [Table 1] below.

  The cloth material of Example 1 had a large difference between the absolute values of “capacitance when empty” and “capacitance when sitting” and the difference between them. From this, it was found that the fabric material (woven fabric or knitted fabric) of Example 1 can discriminate the occupant by the difference in capacitance.

  Also, the cloth material of Example 2 had a large difference between the absolute values of “capacitance when empty” and “capacitance when sitting” and the difference between them. From this, it was found that the occupant can be distinguished from the cloth material of Example 2 by the difference in capacitance.

  The cloth materials of Examples 3 and 4 also had a large difference between the absolute values of “capacitance when empty” and “capacitance when sitting” and the difference between them. From this, it was found that the cloth materials of Examples 3 and 4 can also determine the occupant by the difference in capacitance.

The cloth material of the present embodiment is not limited to the above-described embodiment, and can take other various embodiments.
(1) In the present embodiment, the configuration in which the cloth material 10 is exclusively used as the skin material 4S of the vehicle seat 2 has been described.
The cloth material of this embodiment can be used also as an electrode for measuring an electrocardiogram, for example (refer to biotechnology 44 (1): 177-183 (2006)).
Moreover, the cloth material of this embodiment can also be used as a touch sensor by a capacitive coupling method, and is used, for example, as a control for adjusting the sheet position.

(2) Moreover, in this embodiment, the example which uses the cloth material 10 as the skin material 4S of the seat cushion 4 was demonstrated. The cloth material of this embodiment can be used as a skin material of various configurations of a vehicle seat such as a top plate main portion, a top plate side portion, a stile portion, a back portion, and a headrest portion. In addition to vehicle seats, it can be used as a skin material (sensor electrode, heater) for vehicle interior parts such as a ceiling part, a door part, and a console box.

(3) In the present embodiment, the example in which the plurality of conductive yarns 12 are arranged in parallel with respect to the cloth material 10 has been described. The arrangement relationship of the plurality of conductive yarns is not particularly limited, and may be arranged, for example, in a mesh shape (cross shape, lattice shape) or in a concentric shape.
In this embodiment, an example in which a plurality of conductive yarns are independent from each other has been described. In contrast to this, one conductive thread may be arranged in a zigzag shape on the cloth material.
The conductive yarn 12 may be used as it is, and the conductive yarn having a relatively small fineness may be used by being covered with another insulating fiber (may be used as a covering yarn).

2 Vehicle Seat 4 Seat Cushion 4P Pad Member 4C Groove 4S Skin Material 6 Seat Back 8 Airbag 9 Display Lamp 10 Fabric Material 12 Conductive Yarn 14 Conducting Means 14a Conductive Tape 14b Resin Layer 15 Voltage Applying Means 16 Cable 16a Terminal 18 Measurement Circuit 20 Resin layer 30 Surface material 40 Pad material 50 Back base fabric C ₁ First capacitor C ₂ Second capacitor F Seat frame H Crew

Claims (1)

In the cloth material in which the surface material, the pad material and the back base fabric are laminated in this order,
A cloth material in which the back base cloth is made conductive by a conductive means so that it can be used as an electrode or a heater of a capacitive sensor.

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