JP7319032B2 - Conductive synthetic leather for vehicle seats - Google Patents

Description

TECHNICAL FIELD The present invention relates to synthetic leather having conductivity.

Synthetic leather, which is generally used for chairs and vehicle seats, is an insulator, so static electricity generated when a person stands or sits accumulates in the human body, and in a dry environment such as in winter, the human body becomes a doorknob. If you try to touch a metal such as a battery, an electric discharge will occur, and there is a risk that you will get an electric shock and feel uncomfortable.

In order to solve such problems, Patent Document 1 below proposes an antistatic synthetic leather. The above-mentioned antistatic synthetic leather is a single layer composed of a vinyl chloride resin, an ester having an aliphatic ether structure in the molecule, an ammonium salt represented by a predetermined formula, and a flame retardant in a predetermined range. is a sheet. Patent Document 1 discloses that antistatic synthetic leather exhibits good antistatic properties by adjusting the blending amount of vinyl chloride resin, the blending amount of ester, the number of carbon atoms in the alkyl group contained in the ammonium salt, and the like. It is stated that

Japanese Patent Application Laid-Open No. 09-302183

However, although conventional antistatic synthetic leathers have antistatic properties, they cannot control generated static electricity. That is, if the surface resistance value of the antistatic synthetic leather is too low, static electricity generated when a person stands or sits accumulates in the human body, and the human body becomes a chair or a vehicle seat made of the synthetic leather. If you try to touch it, discharge is likely to occur, and there is a risk of electric shock to the human body. On the other hand, if the surface resistance value is too high, similarly generated static electricity tends to accumulate in the human body (that is, it tends to be electrified), increasing the risk of electric shock to the human body.

The present invention has been made in view of the problems described above. That is, the present invention provides a synthetic leather that is substantially less likely to be charged with static electricity as compared with conventional antistatic synthetic leathers and that can prevent electric shock to the human body.

The conductive synthetic leather for a vehicle seat of the present invention has a conductive skin layer and a conductive fiber base material, and the surface resistance value of the skin layer is 1.0×10 ⁶ Ω or more and 1.0×10 ¹² Ω or less, the surface resistance value of the fiber base material is lower than the surface resistance value of the skin layer, and the ground resistance value is 10×10 ⁶ Ω or more and 1.0×10 ¹¹ Ω or less. and

The conductive synthetic leather of the present invention having the above structure can conduct static electricity in the direction from the skin layer toward the fiber base material. Therefore, the generated static electricity is suppressed from accumulating in the human body, and electric shock to the human body can be prevented. That is, the conductive synthetic leather of the present invention can conduct static electricity in the above direction, so that at least electrification in the skin layer is suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram of the electroconductive synthetic leather concerning 1st embodiment of this invention. FIG. 4 is an explanatory diagram for explaining a method of measuring a ground-to-ground resistance value; It is a cross-sectional schematic diagram of the conductive synthetic leather concerning 2nd embodiment of this invention. It is a cross-sectional schematic diagram of the conductive synthetic leather concerning 3rd embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same constituent elements are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate.
In the present invention or in this specification, conductivity means a phenomenon in which charges such as static electricity flow. In the present invention, the skin layer and the fiber base material are conductive, which means that the skin layer and the fiber base material each contain a conductive agent, so that these layers are endowed with the ability to flow charges such as static electricity. means. In addition, the fact that the skin layer and the fiber base each contain a conductive agent means that when the conductive agent is mixed with the material that constitutes these layers, the material itself that constitutes these layers is imparted with conductivity. provided, conductive agents are provided on the outer surfaces of these layers, and any embodiment of this combination.
The conductive agent referred to in the present invention broadly encompasses materials that impart electrical conductivity to skin materials and fiber substrates, and includes, for example, antistatic agents.
In the following description, the surface of the skin layer opposite to the fiber substrate may be referred to as the front surface, and the surface of the fiber substrate opposite to the skin layer may be referred to as the back surface.

<First Embodiment>
A conductive synthetic leather 100 according to a first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. FIG. 1 is a cross-sectional schematic diagram of a conductive synthetic leather 100 according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating a method of measuring the ground-to-ground resistance value of the conductive synthetic leather 100. As shown in FIG.
The conductive synthetic leather 100 has the skin layer 10 and the fiber base material 20 as shown in FIG. The skin layer 10 is laminated directly or indirectly on one side of the fiber base material 20 . In this embodiment, an adhesive layer 30 is provided between the skin layer 10 and the fiber base material 20 .
Both the skin layer 10 and the fiber base material 20 exhibit conductivity, and the surface resistance value is adjusted. Specifically, the surface resistance value of the skin layer 10 is 1.0×10 ⁶ Ω or more and 1.0×10 ¹² Ω or less, indicating a moderate electric resistance. On the other hand, the surface resistance value of the fiber base material 20 is adjusted to be lower than the surface resistance value of the skin layer 10 . Therefore, in the conductive synthetic leather 100 , the direction of conduction is controlled so that charges such as static electricity are conducted from the skin layer 10 toward the fiber base material 20 . As a result, even if the skin layer 10 comes into contact with the human body and static electricity is generated due to friction or the like, the static electricity is less likely to be charged to the skin layer 10 and is conducted to the fiber base material 20, thereby preventing electric shock to the human body. be.

Although the difference between the surface resistance value of the fiber base material 20 and the surface resistance value of the skin layer 10 described above is not particularly limited, from the viewpoint that the direction of conductivity in the conductive synthetic leather 100 can be well controlled, 1. It is preferably 0×10 ² Ω or more, more preferably 1.0×10 ³ Ω or more. On the other hand, although the upper limit of the difference between the surface resistance value of the fiber base material 20 and the surface resistance value of the skin layer 10 is not particularly limited, it is preferable to substantially adjust the difference to about 1.0×10 ⁹ Ω or less.

Also, the conductive synthetic leather 100 is adjusted so that the ground resistance value is 1.0×10 ⁶ Ω or more and 1.0×10 ¹¹ Ω or less. According to the study of the present inventors, even when the surface resistance value of the fiber base material 20 is adjusted to be lower than the surface resistance value of the skin layer 10 and the conductive direction is controlled, the skin layer 10 temporarily If the time for statically charged charges to decay (charge decay time) is too short, the human body may be electrocuted. have understood. If the amount of charge in the skin layer 10 increases, static electricity tends to accumulate in the human body, and there is a risk that the human body may be electrocuted by some trigger. On the other hand, by adjusting the ground resistance value of the conductive synthetic leather 100 to a range of 1.0×10 ⁶ Ω or more and 1.0×10 ¹¹ Ω or less, the charge decay time can be adjusted, and the skin layer 10 It is possible to satisfactorily avoid electrification in the body, and as a result, electric shock to the human body is prevented.

According to the conductive synthetic leather 100, the skin layer 10 having the texture of the synthetic leather and static electricity in the skin layer 10 generated by friction due to contact with the human body are conducted from the skin layer 10 to the fiber base material 20. That is, electric shock to the human body can be effectively prevented. Therefore, when the conductive synthetic leather 100 is used in applications such as chairs and vehicle seats that often come into contact with the human body, discomfort due to static electricity to the human body is reduced.
Also, the electric charges conducted in the direction from the skin layer 10 toward the fiber base material 20 can be appropriately conducted to the metal member directly or indirectly in contact with the back surface of the fiber base material 20 . Here, the fiber base material 20 indirectly contacts the metal member means that an arbitrary member or space exists between the fiber base material 20 and the metal member, and the fiber base material 20 can conduct electricity to the metal member. It means that both are close to each other.
For example, when the conductive synthetic leather 100 is used as a vehicle seat, if any vehicle metal member is in direct or indirect contact with the fiber base material 20, the static electricity generated on the front surface of the skin layer 10 is Conduction is conducted to the vehicle metal member through the base material 20 . As a result, charging of the conductive synthetic leather 100 itself is well avoided.

The surface resistance values of the skin layer 10 and the fiber base material 20 described above are both based on the method described in IEC Standard 61340-2-3 (2000), and the measurement environment is 23 ± 2 ° C. and 60 ± 5% RH. measured in conditions. The surface resistance value of the skin layer 10 can be appropriately adjusted depending on the amount and type of the conductive agent contained in the skin layer 10 . Moreover, the surface resistance value of the fiber base material 20 can be appropriately adjusted by adjusting the amount and type of the conductive agent contained in the fiber base material 20 .

In addition, the ground-to-ground resistance value of the conductive synthetic leather 100 conforms to the method described in IEC Standard 61340-2-3 (2000), and is measured under the conditions of a measurement environment of 23 ± 2 ° C. and 60 ± 5% RH. .
More specifically, the ground resistance value of the conductive synthetic leather 100 is, as shown in FIG. placed on the substrate. Then, a cylindrical electrode 210 (φ 63 mm, weight 2.3 kg) is arranged near an arbitrary corner of the arranged conductive synthetic leather 100, and is grounded on the fiber base layer 20 side on the diagonal side of the corner. Place metal 220 (50 mm x 50 mm aluminum tape). The distance d between the cylindrical electrode 210 and the grounding metal 220 is set to 60 mm. A 1-kg weight (not shown) is placed above the conductive synthetic leather 100 and above the grounding metal 220 so that the fiber base material 20 and the grounding metal 220 are securely in contact with each other. Then, the cylindrical electrode 210 and the measuring device 230, and the grounding metal 220 and the measuring device 230 are electrically connected with the conductive wire 240, respectively, and the electrical resistance is measured.
The ground-to-ground resistance value of the conductive synthetic leather 100 is a combination of the surface resistance values of the skin layer 10 and the fiber base material 20, the layer thicknesses of these layers, and the materials and thicknesses of other layers optionally provided in the conductive synthetic leather 100. can be adjusted as appropriate.

By the way, in general, if synthetic leather (skin layer 10) contains a large amount of a conductive agent, the texture may deteriorate compared to synthetic leather that does not contain a conductive agent. In view of such circumstances, in the present embodiment, setting the surface resistance value of the skin layer 10 to 1.0×10 ⁹ Ω or more and 1.0×10 ¹² Ω or less can be said to be one of the more preferable aspects. This is because within such a range, it is possible to reduce the amount of conductive agent contained in the skin layer 10 and suppress electrification in the skin layer 10 while maintaining the texture of the synthetic leather at a high level.
In particular, the surface resistance value of the skin material is set to 1.0×10 ⁹ Ω or more and 1.0×10 ¹² Ω or less, and the difference between the surface resistance value of the fiber base material 20 and the surface resistance value of the skin layer 10 is 1. By adjusting the resistance to 0×10 ² Ω or more, the direction of conductivity in the conductive synthetic leather 100 can be reliably controlled in a desired direction while maintaining the texture of the synthetic leather at a high level.

Further, according to the studies of the present inventors, when the surface resistance value of the skin layer 10 is set low within the range shown above, the static electricity generated by friction between the human body and the skin layer 10 is reliably transferred to the skin layer 10 side. It was found that electric shock to the human body can be avoided by temporarily electrifying. In addition, when the skin layer 10 with a relatively low surface resistance value is provided, sufficient conductivity can be obtained even if the difference between the surface resistance value of the fiber base material 20 and the surface resistance value of the skin layer 10 is not so large. It was found that the electrical conductivity of the synthetic leather 100 can be controlled from the skin layer 10 toward the fiber base material 20.
Specifically, from the viewpoint of stably providing higher electrical performance without an economic disadvantage, the surface resistance value of the skin layer 10 is 1.0×10 ⁶ Ω or more and 1.0×10 ⁹ A preferable example is an embodiment in which the surface resistance value is less than Ω and the difference between the surface resistance value of the fiber base material 20 and the surface resistance value of the skin layer 10 is 1.0×10 ⁵ Ω or less.

Each configuration of the conductive synthetic leather 100 will be described in further detail below.
(skin layer)
The skin layer 10 is a resin layer that exhibits conductivity and has the texture of synthetic leather. The skin layer 10 may have a single-layer structure as shown in FIG. 1, or may be composed of a plurality of layers (not shown). Although the thickness of the skin layer 10 is not particularly limited, it is preferably formed to a thickness of 10 μm or more and 60 μm or less, and more preferably formed to a thickness of 20 μm or more and 50 μm or less. The surface of the skin layer 10 may be appropriately provided with a tie pattern or the like.
As the resin constituting the skin layer 10, any resin that can be used for the skin layer of synthetic leather can be used. Examples of the resin include polyurethane-based resins and vinyl chloride-based resins.

As the polyurethane-based resin, any can be used as long as it can be used for the skin layer of synthetic leather. Specifically, polyester-based polyurethane resin, polyether-based polyurethane resin, polycaprolactone-based polyurethane resin, polyester/ Polyether copolymer polyurethane resins, polyamino acid/polyurethane copolymer resins, non-yellowing polycarbonate polyurethane resins obtained by reacting a polycarbonate diol component, a non-yellowing diisocyanate component, a low-molecular chain extender, and the like. Polyvinyl chloride resin, synthetic rubber, or the like may be mixed with the polyurethane resin as long as it does not impair the physical properties of the synthetic leather.

The method of manufacturing the skin layer 10 made of polyurethane resin is not particularly limited. In general, polyols, polyisocyanates, and cross-linking agents are dissolved in organic solvents such as methyl ethyl ketone, toluene, and dimethylformamide, and solvents such as water. , UV absorbers, antioxidants, flame retardants, cross-linking agents and other various additives are added to prepare a polyurethane resin solution. Then, the skin layer 10 can be manufactured by coating the polyurethane-based resin solution on release paper or the like, drying it, and cross-linking it. The polyurethane resin solution may be of either one-liquid type or two-liquid type.

Any vinyl chloride-based resin that can be used in the skin layer of synthetic leather can be used as the vinyl chloride-based resin. Polymers or blends of these resins can be used.
Other monomers copolymerizable with the vinyl chloride monomer include, for example, ethylene, propylene, vinyl acetate, vinylidene chloride, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, maleic acid, acrylonitrile fumarate, and the like. be done.

When the skin layer 10 is made of a vinyl chloride resin, a plasticizer is blended together with the vinyl chloride resin in order to more effectively exhibit flexibility similar to that of natural leather. As the plasticizer, a polymer plasticizer which is an organic compound having a number average molecular weight of 800 or more and 4000 or less is preferably selected. More specifically, polymer plasticizers are exemplified by polymer polyester plasticizers. Adipic acid-based polyester plasticizers are exemplified as polymer polyester-based plasticizers. For the technology of synthetic leather containing vinyl chloride resin and plasticizer, see Chinese patent application 201810173137.5, for example.
In addition to the polymeric plasticizers described above, plasticizers other than polymeric plasticizers may also be included as plasticizers. Plasticizers other than polymeric plasticizers that can be blended with polymeric plasticizers include trimellitic acid plasticizers, phthalic acid plasticizers, linear dibasic acid plasticizers, and phosphoric acid plasticizers. be able to. From the viewpoint of versatility, phthalic acid-based plasticizers are preferred.

The method of manufacturing the skin layer 10 made of vinyl chloride resin is not particularly limited. In general, the selected vinyl chloride resin and plasticizer are dissolved in a solvent such as an organic solvent or water, and if necessary, a conductive agent, a coloring agent, a filler, a light stabilizer, an ultraviolet absorber, A vinyl chloride resin solution is prepared by adding various additives such as an antioxidant, a flame retardant, and a cross-linking agent. Then, the skin layer 10 can be manufactured by coating the vinyl chloride resin solution on release paper or the like, drying it, and cross-linking it.

The skin layer 10 exhibits electrical conductivity. The means for imparting conductivity to the skin layer 10 is not particularly limited as long as the surface resistance value of the skin layer 10 can be adjusted to 1.0×10 ⁶ Ω or more and 1.0×10 ¹² Ω or less.
Specifically, for example, the skin layer 10 may be formed by adding a conductive agent to the polyurethane-based resin solution or vinyl chloride-based resin solution described above and using the manufacturing method described above.
As another means, conductivity can be imparted to the skin layer 10 by applying a conductive paint to the surface of the skin layer 10 to form a conductive layer on the surface of the skin layer 10.
Of course, the above-described two means for imparting conductivity may be combined, or different means may be employed as appropriate.

The conductive agent may be any material that can impart conductivity to the resin layer. For example, carbon-based conductive materials such as carbon black, zinc oxide, indium tin oxide (ITO), or antimony tin oxide (ATO ), surfactants, or combinations thereof.
Examples of the surfactant include anionic antistatic agents (phosphate ester derivatives, etc.), cationic antistatic agents (amine-based quaternary ammonium salt derivatives, etc.), nonionic antistatic agents (polyhydric alcohol esters, ethylene adducts of fatty acid oxide, etc.), amphoteric antistatic agents (bentine type, imidazoline type, etc.), and the like.
When the resin constituting the skin layer 10 is a vinyl chloride resin, a conductive plasticizer such as a phthalate ester such as dioctyl phthalate (DOP) or an adipate ester such as dioctyl adipate (DOA) is used. may be added as a conductive agent.

Examples of conductive paints include paints containing one or more of the conductive agents described above.

(fiber base material)
The fiber base material 20 is a base material that exhibits conductivity and supports the skin layer 10 . Although the thickness of the fiber base material 20 is not particularly limited, the thickness is preferably 100 μm or more and 2000 μm or less, considering that the synthetic leather has the same flexibility as that of the natural leather. It is preferably 300 μm or more and 1000 μm or less, more preferably. Although the basis weight of the fiber base material 20 is not particularly limited, it is 10 g/m ² considering that the synthetic leather should have flexibility similar to that of the natural leather, as described in relation to the thickness. It is preferably 500 g/m ² or more, and more preferably 20 g/m ² or more and 300 g/m ² or less.

The fiber base material 20 is not particularly limited, and may be any cloth material using fibers, such as knitted fabric, woven fabric, and non-woven fabric. The fibers forming the fiber base material 20 are not particularly limited, and synthetic fibers, natural fibers, and the like can be mentioned. Examples of synthetic fiber materials include, but are not limited to, polyester, polyamide, acrylic, and nylon. Examples of natural fiber materials include cotton, linen, and rayon.

The means for imparting conductivity to the fiber base material 20 is not particularly limited, and known conductive fibers can be appropriately selected, or can be appropriately manufactured by a known conductive fiber manufacturing method. For example, a cloth material manufactured using conductive yarn containing a conductive material can be used as the fiber base material 20 . In this case, all fibers constituting the cloth material may be conductive yarns, or conductive yarns may be partially used. For example, in the case of a cloth material such as a knitted fabric or a woven fabric, if at least one of the warp and the weft is a conductive thread, the conductive fiber base material 20 can be used. The conductive fiber base material 20 can also be manufactured by coating a cloth material with a conductive paint, or by immersing a cloth material in a liquid conductive material and drying it.

For example, the conductive fiber base material 20 is preferably conductive using a polymer-based conductive material such as a π-electron conjugated conductive polymer or a carbon-based conductive material such as carbon graphite.
Specifically, a fiber base material 20 manufactured by directly depositing a polymer-based conductive material on the surface of a cloth material by a chemical oxidation polymerization method, or a conductive paint containing a polymer-based conductive material or a carbon-based conductive material. A conductive fiber base material 20 manufactured by immersing a cloth material in and coating and drying it can be mentioned.
Alternatively, a conductive yarn may be obtained by a chemical oxidation polymerization method using a polymer-based conductive material, and a cloth material manufactured by weaving the conductive yarn into a fiber base material may be used as the conductive fiber base material 20 .

The conductive agent contained in the fiber base material 20 may be the same member as the conductive agent contained in the skin layer 10, or may be a different member.

(adhesive layer)
Next, the adhesive layer 30 will be explained. In the conductive synthetic leather 100, the skin layer 10 may be directly laminated on the fiber base material 20, but as shown in FIG. to fix the fiber base material 20 and the skin layer 10 to each other.
In this embodiment, the adhesive layer 30 is a layer that bonds the skin layer 10 and the fiber base material 20 together. The adhesive layer 30 may or may not be conductive. The adhesive layer 30 may be any material that can bond the skin layer 10 and the fiber base material 20 within the scope of the present invention.

For example, the adhesive layer 30 can be configured using an adhesive. Examples of adhesives include polyurethane-based resins, polyvinyl chloride-based resins, vinyl acetate-based resins, rubber-based resins, and the like.
Examples of the polyurethane-based resin that is an adhesive include known two-component urethane resin-based adhesives such as polycarbonate-based polyurethane, polyether-based polyurethane, polyester-based polyurethane, polyester/polyether-based polyurethane, and lactone-based polyurethane. .

The adhesive is applied to the surface of the skin layer 10 facing the fiber base material 20 . The amount of the adhesive applied to the skin layer 10 is not particularly limited, but for example, the thickness after drying may be about 40 μm or more and 120 μm or less.

A foaming adhesive can be used as the adhesive layer 30 composed of a material other than the adhesive described above. A technique for bonding the first layer (skin layer 10) and the opposing second layer (fiber base material 20) with a foam adhesive is disclosed in WO2014/192283, for example.
Specifically, the adhesive layer 30 made of a foam adhesive comprises a urethane prepolymer whose terminal isocyanate groups are blocked with a blocking agent, and a urethane adhesive containing an amine cross-linking agent and thermally expandable fine particles. It can be formed of a polyurethane resin containing foamed thermally expandable fine particles, which is obtained by heating to foam the thermally expandable fine particles and causing a cross-linking reaction between a urethane prepolymer and an amine-based cross-linking agent.
As the urethane prepolymer whose terminal isocyanate group is blocked with a blocking agent, for example, a reaction product of an aliphatic diol and phosgene, diallyl carbonate or cyclic carbonate as described in JP-A-2006-70059. and a urethane prepolymer obtained from a polycarbonate diol that is liquid at 25° C. and an organic diisocyanate, and the terminal isocyanate groups of the urethane prepolymer are blocked with a blocking agent.
Aliphatic polyamines such as ethylenediamine, 1,2-propanediamine, and 1,3-propylenediamine are used as the amine-based cross-linking agent.
Examples of the thermally expandable fine particles include microcapsules in which a liquid low-boiling-point hydrocarbon that is vaporized by heating is wrapped in a thermoplastic resin film such as an acrylonitrile-based resin.

The adhesive layer 30 made of a foaming adhesive is formed by coating the surface of the skin layer 10 facing the fiber base material 20 with a polyurethane resin containing foamed thermally expandable fine particles. By laminating the fiber base material 20 on the adhesive layer 30 before the polyurethane resin is completely cured, the fiber base material 20 and the skin layer 10 are fixed to each other.
The thickness of the adhesive layer 30 formed from the foam adhesive is not particularly limited, but the thickness after curing may be, for example, about 50 μm to 1000 μm.

(Production method)
The method for producing the conductive synthetic leather 100 is not particularly limited, but in general, a resin solution for forming the skin layer 10 is applied on a release carrier such as release paper, and the solvent in the applied resin solution is removed. The surface layer 10 is formed by evaporating and drying and causing a cross-linking reaction of the resin. A knife coater, a comma doctor, a roll coater, a reverse roll coater, a rotary screen coater, a gravure coater, and other suitable means are employed for applying the resin solution. The release carrier such as release paper may have a smooth surface on the side to which the resin solution is applied, or may have a tie pattern or the like.
Next, the adhesive layer 30 is applied to the surface of the skin layer 10 as described above, and then the fiber base material 20 is laminated on the adhesive layer 30, and then the release carrier is peeled off, whereby the conductive synthetic leather 100 is produced. be done. When the adhesive is a foaming adhesive, after laminating the fiber base material 20 with the adhesive layer 30, it is heated to foam the thermally expandable fine particles contained in the adhesive layer 30, and the isocyanate group is blocked with urethane. The prepolymer may be deblocked to crosslink the urethane prepolymer and the amine-based crosslinker to complete the adhesive layer 30 .

Any layer such as a surface treatment layer (not shown) may be formed on the surface of the skin layer 10 as necessary. The surface treatment layer is provided on the surface of the skin layer 10 as necessary for the purpose of polishing the surface of the skin layer 10 or the like. The surface treatment layer can be provided by coating the surface of the skin layer 10 with a coating liquid in which, for example, polyurethane resin, silicone, organic filler, etc. are dispersed in an organic solvent or water. When an arbitrary layer such as a surface treatment layer is provided on the surface of the skin layer 10, the surface resistance value of the skin layer 10 is the surface of the surface treatment layer opposite to the skin layer 10 (that is, the exposed surface). can be measured in

The conductive synthetic leather 100 preferably has a charge decay time of 0.3 seconds or more and 60 seconds or less, more preferably 0.3 seconds or more and 30 seconds or less, as measured by the test method described below. It is particularly preferable to be 3 seconds or more and 20 seconds or less. If the charge decay time is 0.3 seconds or longer, discharge from the skin layer 10 toward the human body is less likely to occur, and electric shock to the human body is remarkably suppressed. If the charge decay time exceeds 60 seconds, the skin layer 10 is likely to be charged with static electricity, and the human body is likely to be charged with static electricity, increasing the risk of electric shock to the human body.

The test method for measuring the charge decay time is a test stand (electrode) charged to 2000 V in a measurement environment of 23 ± 2 ° C. and 60 ± 5% RH in accordance with IEC61340-2-1 (2002). Place the conductive synthetic leather 100 with the skin layer 10 on the bottom side, apply a voltage, then bring the ground wire into contact with the fiber base material 20, and wait until the voltage of the conductive synthetic leather 100 reaches 200 V. This is a method of measuring and using this as the charge decay time. The measuring device used for the above measurement may be any device capable of applying a desired voltage to the sample and measuring the time it takes for the voltage to drop to a predetermined voltage when grounded. For example, a charged plate monitor (manufactured by Hugle Electronics) can be used.

The thickness of the conductive synthetic ^leather 100 ^is not particularly limited. thickness.

<Second embodiment>
A second embodiment of the present invention will be described below with reference to FIG. FIG. 3 is a cross-sectional schematic diagram of the conductive synthetic leather 110 according to the second embodiment of the present invention.
The conductive synthetic leather 110 according to the present embodiment is configured in the same manner as the conductive synthetic leather 100 described above, except that the foamed resin layer 40 is provided between the skin layer 10 and the fiber base material 20. . Therefore, regarding the conductive synthetic leather 110 , the description of the conductive synthetic leather 100 can be referred to as appropriate for the configuration other than the foamed resin layer 40 .

In conductive synthetic leather 110 , foamed resin layer 40 is laminated on one surface side of skin layer 10 , and foamed resin layer 40 and fiber base material 20 are fixed to each other via adhesive layer 30 . The conductive synthetic leather 110 provided with the foamed resin layer 40 has moderate elasticity and flexibility. Therefore, for example, when the conductive synthetic leather 110 is used as a surface member of a chair or a vehicle seat, it is comfortable to sit on and feels good to the touch. Although the thickness of the foamed resin layer 40 is not particularly limited, it is preferably about 100 μm or more and 500 μm or less.

The foamed resin layer 40 and the surface layer 10 may be directly adhered to each other, or may be adhered by an adhesive layer (not shown). The adhesive layer can be formed in the same manner as the adhesive layer 30 described above. The foamed resin layer 40 is in a foamed state unlike the surface layer 10 and has a cell structure with cell walls. The cell structure is preferably a layer of closed cells from the viewpoint that even if creases or wrinkles are formed in the synthetic leather, it can be easily restored.

The foamed resin layer 40 may be conductive or non-conductive. When it is desired to form the foamed resin layer 40 having conductivity, the foamed resin layer 40 may contain the conductive agent described above. In this embodiment, even if the foamed resin layer 40 does not have electrical conductivity, the electric charge conduction direction from the skin layer 10 to the fiber base material 20 can be controlled.

The foamed resin layer 40 may be formed by laminating a pre-formed thin sheet-like foamed resin on the skin layer 10. However, the foamed resin layer 40 having a base resin, a plasticizer and a foaming agent on one side surface of the skin layer 10 may be formed. It is also possible to form the foamed resin layer 40 by applying a resin composition for forming a resin layer to promote a heated and foamed state.

Examples of the base resin used to form the foamed resin layer 40 include polyurethane-based resins and vinyl chloride-based resins.

A method for forming the foamed resin layer 40 is not particularly limited.
As an example, when forming the foamed resin layer 40 composed of a polyurethane resin, for example, a resin for forming a foamed resin layer containing a two-liquid type polyurethane resin, an amine cross-linking agent such as an aliphatic diamine, and a foaming agent A composition is prepared. Then, the foamed resin layer 40 can be formed in the same manner as the adhesive layer 30 formed from the foamed adhesive.

As another example, when forming the foamed resin layer 40 composed of a vinyl chloride-based resin, for example, the foamed resin layer containing a vinyl chloride-based resin containing a structural unit derived from vinyl chloride, a plasticizer, and a foaming agent A forming resin composition is prepared. Then, the foamed resin layer 40 can be formed in the same manner as the adhesive layer 30 formed from the foamed adhesive.
Examples of the vinyl chloride resin include vinyl chloride homopolymers, vinyl chloride/vinyl acetate copolymers, vinyl chloride/ethylene copolymers, vinyl chloride/propylene copolymers, vinyl chloride/styrene copolymers, and the like. can include, but are not limited to.
Examples of the plasticizer include, but are not limited to, phthalate plasticizers, trimellitate plasticizers, and linear dibasic ester plasticizers.

Examples of the foaming agent include azodicarbonamide (ADCA), 4,4'-oxybis[benzenesulfonylhydrazide] (OBSH), N,N'-dinitrosopentamethylenetetramine (DPT), thermally expandable microcapsules, and the like. can be done.

The conductive synthetic leather 110 can be manufactured by forming the adhesive layer 30 described above on the exposed surface of the foamed resin layer 40 and further laminating the fiber base material 20 thereon.

<Third embodiment>
A third embodiment of the present invention will be described below with reference to FIG. FIG. 4 is a schematic cross-sectional view of a conductive synthetic leather 120 according to a third embodiment of the invention. The conductive synthetic leather 120 according to this embodiment is configured in the same manner as the conductive synthetic leather 100 described above, except that the metal layer 50 is provided on one side surface of the fiber base material 20 . Therefore, regarding the conductive synthetic leather 120 , the description of the conductive synthetic leather 100 can be referred to as appropriate for the configuration other than the metal layer 50 .

As shown in FIG. 4, the conductive synthetic leather 120 has a metal layer 50 laminated to at least a portion of the surface of the fiber base material 20 opposite to the skin layer 10 side, to which a ground wire 52 is connected. The end of ground wire 52 opposite metal layer 50 can be connected to any conductor. As a result, charges such as static electricity conducted from the skin layer 10 toward the fiber base material 20 flow from the metal layer 50 to the ground wire 52 . Therefore, the electrically conductive synthetic leather 120 satisfactorily suppresses electrification even when a conductor such as metal is not in direct or indirect contact with the back surface of the fiber base material 20 .

The metal forming the metal layer 50 is not particularly limited, and examples thereof include aluminum. The metal layer 50 in the present embodiment is in the form of a thin sheet, and when a person sits down from the surface side of the skin layer 10 while being laminated on a part of the back side of the fiber base material 20, the metal layer It obscures the existence of 50. In order to better prevent the physical discomfort due to the metal layer 50 being laminated on the back surface, for example, like conductive synthetic leather 110, foaming between the skin layer 10 and the fiber base material 20 A resin layer 40 is preferably provided.

The first to third embodiments of the present invention have been described above. INDUSTRIAL APPLICABILITY The synthetic leather of the present invention can be used in various applications, and is particularly preferably used in applications where static electricity can be generated by friction with the human body. For example, the conductive synthetic leather of the present invention is preferably used as a synthetic leather for automobile seats. The static electricity generated between the human body and the seat surface is less likely to be charged to the human body side, and the unpleasant feeling of electric shock and electrification that the vehicle user has hitherto felt can be remarkably reduced. In addition, the conductive synthetic leather of the present invention can also be preferably used as a floor material for clean rooms in which precision equipment such as semiconductor manufacturing equipment is installed.

Examples of the present invention are shown below.
The conductive fiber base materials 1 to 4 used in each example and each comparative example were produced as follows.
(Fibrous base material 1)
1% by mass of pyrrole (manufactured by Koei Chemical Industry Co., Ltd.) as a π-electron conjugated polymer monomer, 10% by mass of ferric p-toluenesulfonate (manufactured by Tayca Corporation) as an oxidation polymerization agent and dopant agent, and 89% by mass of purified water A conductive agent solution containing was prepared.
A cloth material (circular polyester knit: thickness 0.75 mm (basis weight 293 g/m ² ), polyester yarn (single filament fineness 4.2 denier)) is immersed in the conductive agent liquid to polymerize the pyrrole monomer (chemical A conductive fiber base material 1 was obtained by directly depositing polypyrrole on the surface of each fiber of the fiber base material.
(Fiber base material 2)
A polyester yarn (single filament fineness 4.2 denier) is immersed in the same conductive liquid as that used in the production of the fiber base material 1, and the pyrrole monomer is directly polymerized to the yarn under the same conditions as the fiber base material 1 ( chemical oxidation polymerization method) to obtain a conductive yarn. Conductive polyester knit (circular knitted polyester knit: thickness 0.75 mm (basis weight 293 g/m ² ), and this was used as the fiber base material 2 .
(Fibrous base material 3)
As the conductive yarn, 20% copper sulfide fiber (Nihon Sanmo Dyeing Co., Ltd., trade name “Thunderon”), which is a commercially available conductive yarn, and polyester yarn not imparted with conductivity (single yarn fineness 4.2 denier) ) was used to prepare a conductive polyester knit (circular polyester knit: thickness 0.75 mm (basis weight 293 g/m ² ), which was used as the fiber base material 3 .

(Fiber base material 4)
As the conductive yarn, 2% copper sulfide fiber (Nihon Sanmo Dyeing Co., Ltd., trade name “Thunderon”), which is a commercially available conductive yarn, and polyester yarn (single yarn fineness 4.2 denier) not imparted with conductivity. ) was used to prepare a conductive polyester knit (circular polyester knit: thickness 0.75 mm (basis weight 293 g/m ² )), which was used as the fiber base material 4 .

(Example 1)
20 parts by mass each of dimethylformamide and methyl ethyl ketone as solvents and 5 parts of zinc oxide as a conductive agent are added to 100 parts by mass of a one-liquid type polyester polyurethane resin (manufactured by Dainichiseika Kogyo Co., Ltd., trade name "Rezamin ME-44LP"). After adding parts by mass, the mixture was mixed and stirred to prepare a polyurethane-based resin solution. The above polyurethane-based resin solution was applied to the textured surface of the release paper so that the thickness after drying was 25 μm, and dried in an oven at 100° C. for 2 minutes to obtain a skin layer.
The details of the materials used above are as follows.
・ Zinc oxide (manufactured by Hakusui Tech Co., Ltd., product name “23-K”)
・ Release paper (manufactured by Dai Nippon Printing Co., Ltd., product name “DE-73”)

Next, the following adhesive was applied to the exposed side surface of the skin layer obtained as described above so that the thickness after drying was 50 μm, and dried in an oven at 100° C. for 2 minutes to obtain a semi-dry adhesive layer. On this semi-dry adhesive layer, the conductive fiber base material 1 is attached, and after promoting the cross-linking reaction of the synthetic resin contained in the adhesive at 50° C. for 48 hours, the release paper is peeled off to synthesize the conductive material. got leather.

The adhesive contains 20 parts by weight of dimethylformamide as a solvent, 12 parts by weight of a trimethylolpropane addition product of toluene diisocyanate (TDI) as a cross-linking agent, and 3 parts by weight of an amine-based catalyst with respect to 100 parts by weight of a polyester-based polyurethane resin. The additions were prepared by mixing and stirring.
The details of the above composition are as follows.
・Polyester polyurethane resin (manufactured by DIC Corporation, trade name “Crisbon C4070”)
・ Trimethylolpropane addition product of TDI (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name “Coronate L”)
・ Amine-based catalyst (manufactured by DIC Corporation, trade name “Accel S”)

(Examples 2-4)
A conductive synthetic leather was obtained in the same manner as in Example 1, except that the type and blending amount of the conductive agent were as shown in Table 1.
As the carbon black used as the antistatic agent shown in Table 1, the trade name "CAB" manufactured by Toyocolor Co., Ltd. was used.

(Example 5)
A conductive synthetic leather was obtained in the same manner as in Example 1, except that the fiber base material 2 was used.

(Example 6)
A conductive synthetic leather was obtained in the same manner as in Example 1, except that the fiber base material 3 was used.

(Example 7)
A conductive synthetic leather was obtained in the same manner as in Example 1 except that a foamed resin layer was laminated between the skin layer and the adhesive layer in Example 1 as described below.
The foamed resin layer was formed as follows.
To 100 parts by mass of a two-liquid type polyurethane resin, 5 parts by mass of an aliphatic diamine as a cross-linking agent, 1 part by mass of thermally expandable fine particles, and 15 parts by mass of dimethylformamide as a solvent are added, mixed and stirred to form a foamed resin layer. A foamed resin composition was prepared and applied to the exposed side surface of the skin layer so that the thickness after drying was 275 μm, and heated in an oven at 180° C. for 2 minutes to obtain a foamed resin layer.
The details of the above composition are as follows.
・ Two-liquid type polyurethane resin (manufactured by DIC Corporation, trade name “Urehyper SU-009”)
・ Aliphatic diamine (manufactured by BASF Japan Ltd., trade name “Lalomin C260”)
・ Thermally expandable microparticles (thermally expandable microcapsules with a maximum expansion temperature of 160 to 180 ° C., an average particle size of 30 μm, and an expansion rate of about 7 times, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name “Matsumoto Microsphere FN-100MD”)

(Comparative example 1)
A synthetic leather was obtained in the same manner as in Example 1, except that no conductive agent was used.

(Comparative example 2)
A conductive synthetic leather was obtained in the same manner as in Example 1, except that the type and blending amount of the conductive agent were as shown in Table 1.

(Comparative Example 3)
A conductive synthetic leather was obtained in the same manner as in Example 1, except that the type and blending amount of the conductive agent were shown in Table 1 and that the fiber base material 4 was used.

For each example and each comparative example obtained as described above, the electrical performance was measured as follows. The measurement results are shown in Table 1.

(Measurement of surface resistance)
The surface resistance values of the skin layer and the fiber base material were measured according to the method described in IEC Standard 61340-2-3 (2000) under the conditions of a measurement environment of 23±2° C. and 60±5% RH.
As a measuring device, a trade name "PRS-801" manufactured by Prostat Co., Ltd. was used, and the distance between the electrodes was set to 60 mm.

(Measurement of resistance between grounds)
The ground-to-ground resistance value of each example and each comparative example was measured according to the method described in IEC Standard 61340-2-3 (2000) under conditions of a measurement environment of 23±2° C. and 60±5% RH. It was measured in the same manner as described with reference to FIG. 2 regarding one embodiment. Hiresta-UP (MCP-HT450) manufactured by Mitsubishi Chemical Analytech Co., Ltd. was used as the measuring device, the measuring probe was a UA probe (2-pin type: 20 mm between pins, φ2 mm at pin tip), and the applied voltage was 100V.

(Measurement of frictional electrification voltage)
Using a friction cloth (hair No. 1-1) specified in JIS L0803 (2011), under the conditions of a measurement environment of 23 ± 2 ° C and 60 ± 5% RH, each example and each comparative example by the following method Friction The charged voltage was measured. As a measuring device, a trade name "MODEL520" manufactured by Trec was used.
A 50 mm × 50 mm aluminum tape is folded in half and pasted over the skin layer and the fiber layer at any outer edge of the synthetic leather, and the aluminum tape is brought into contact with the skin layer and the fiber base material by about 25 mm × 50 mm. rice field. A ground wire was connected to the aluminum tape. Then, the surface of the skin layer was rubbed 5 times for 3 seconds with a friction cloth folded to a width of 70 mm under a load of about 1 to 2 kg. The charge amount in the skin layer immediately after rubbing was measured with the above measuring device.

(charge decay time)
The charge decay time of each example and each comparative example was measured according to the method described in IEC Standard 61340-2-1 (2002), under the conditions of a measurement environment of 23 ± 2 ° C. and 60 ± 5% RH, to 2000 V. Place the conductive synthetic leather on the electrified test table (electrode) with the skin layer on the bottom side and apply voltage, then bring the ground wire into contact with the back side of the fiber base until the voltage reaches 200V. time was measured. A charged plate monitor (manufactured by Hugle Electronics) was used as a test device.

(comprehensive evaluation)
From the triboelectric voltage and charge decay time values measured as described above, each example and each comparative example were evaluated according to the following criteria. Evaluation results are shown in Table 1.
Frictional electrification voltage is 1000 V or less, and charge decay time is 0.3 seconds or more and 60 seconds or less...○
Triboelectric voltage is over 1000 V and/or charge decay time is less than 0.3 seconds... ×
Triboelectric voltage is over 1000 V and/or charge decay time is over 60 seconds... ×

DESCRIPTION OF SYMBOLS 10... Skin layer 20... Fiber base material 30... Adhesive layer 40... Foamed resin layer 50... Metal layer 52... Earth wire 100, 110, 120... Conductive synthetic leather 210... Cylindrical electrode 220... Grounding metal 230... Measuring device 240... Conductive wire d... Distance

The above embodiments include the following technical ideas.
(1) having a conductive skin layer and a conductive fiber substrate;
The surface resistance value of the skin layer is 1.0×10 ⁶ Ω or more and 1.0×10 ¹² Ω or less,
The conductive material is characterized in that the surface resistance value of the fiber base material is lower than the surface resistance value of the skin layer, and the resistance value between grounds is 1.0×10 ⁶ Ω or more and 1.0×10 ¹¹ Ω or less. synthetic leather.
(2) The conductive synthetic leather according to (1) above, wherein the difference between the surface resistance value of the fiber base material and the surface resistance value of the skin layer is 1.0×10 ² Ω or more.
(3) The conductive synthetic leather according to (1) or (2) above, wherein the skin material has a surface resistance value of 1.0×10 ⁹ Ω or more and 1.0×10 ¹² Ω or less.
(4) The conductive synthetic leather according to (3) above, wherein the difference between the surface resistance value of the fiber base material and the surface resistance value of the skin layer is 1.0×10 ³ Ω or more.
(5) The skin material has a surface resistance value of 1.0×10 ⁶ Ω or more and less than 1.0×10 ⁹ Ω, and a difference between the surface resistance value of the fiber base material and the surface resistance value of the skin layer. is 1.0×10 ⁵ Ω or less, the conductive synthetic leather according to the above (1) or (2).
(6) Any one of (1) to (5) above, wherein a metal layer connected to a ground wire is laminated on at least a part of the surface of the fiber base material opposite to the skin layer side. Conductive synthetic leather according to.
(7) The conductive synthetic leather according to any one of (1) to (6) above, which includes a foamed resin layer between the skin layer and the fiber base material.
(8) The conductive synthetic leather according to any one of (1) to (7) above, which is for automobile seats.
(9) The conductive synthetic leather according to any one of (1) to (7) above, which is used as a floor material for clean rooms in which precision equipment is installed.

Claims (2)

having a conductive skin layer and a conductive fiber substrate,
The surface resistance value of the skin layer is 1.0×10 ⁶ Ω or more and 1.0×10 ¹² Ω or less,
A vehicle , wherein the surface resistance value of the fiber base material is lower than the surface resistance value of the skin layer, and the ground resistance value is 1.0×10 ⁶ Ω or more and 1.0×10 ¹¹ Ω or less. Conductive synthetic leather for seats . 2. The conductive synthetic leather for a vehicle seat according to claim 1, wherein the difference between the surface resistance value of said fiber base material and the surface resistance value of said skin layer is 1.0*10 ^<2 > [Omega] or more.

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