JP2021196286A - Elastic capacitor - Google Patents

Abstract

To provide an attachable/detachable elastic capacitor configured not to interfere with body movement when it is applied to a clothing type, and to prevent sensor damage when it is excessively stretched.SOLUTION: An attachable/detachable elastic capacitor comprises a conductive laminate including a first elastic cover layer, a first elastic conductive layer, an elastic dielectric layer, a second elastic conductive layer and a second elastic cover layer in this order, where the conductive laminate removably engages with an elastic base material at two or more points, and where disengagement force of the engagement parts is not less than 1 N and not more than 10 N.SELECTED DRAWING: Figure 1

Description

The present invention relates to a removable elastic capacitor that detects elongation strain or elongation displacement from a change in capacitance due to tensile deformation of a capacitor element.

Conventionally, sensor elements that detect displacement, strain, pressure, etc. from changes in electrical characteristics due to deformation of deformable elements have been known. For example, Patent Document 1 has a sheet-like dielectric layer made of an elastomer composition, and a first electrode layer and a second electrode layer formed so as to partially face the front surface and the back surface of the dielectric layer. Capacitance type characterized by being provided with a sensor body that is reversibly deformed so that the area of the front and back surfaces of the layer changes, and a stretchable cloth material that is integrated with the sensor body and has stretch resistance. Sensor sheets have been proposed.

Patent Document 2 includes a stretchable sheet-like cloth and a strain sensor having a resistor laminated in a predetermined area on one surface side of the cloth, and the cloth is provided in at least a part of the predetermined area. A fabric with a strain sensor has been proposed, characterized in that the surface layer on one surface side has a composite layer containing fibers and resins that contribute to the adhesion of the strain sensor.

Japanese Unexamined Patent Publication No. 2016-97087 Japanese Unexamined Patent Publication No. 2015-078967

However, when the above-exemplified sensor is applied to a garment-type sensing device, there is a problem that when the garment is made of a cloth having stretch anisotropy, the body movement in the difficult extension direction is hindered. In addition, when the fabric and the strain sensor are bonded together with a composite layer of fiber and resin, the elongation of the fabric is directly transmitted to the strain sensor, and the elongation other than the originally desired elongation direction is detected, which causes noise. It became. In addition, when the sensor itself is deformed more than expected, the deformation cannot be controlled, and the sensor is damaged. That is, when applied to a clothing-type sensing device, it is considered that the conventional element for detecting deformation does not consider both the degree of freedom of body movement and the detection accuracy.

The present invention has been made in view of such circumstances, and an object of the present invention is to accurately detect deformation that is originally desired to be detected while ensuring free body movement when applied to a clothing-type sensing device. Since it can be easily attached and detached, it is an object of the present invention to provide a detachable elastic capacitor in which the sensor is less likely to be damaged even when a load more than expected is applied to the sensor.

That is, the present invention has the following configuration.
[1] A conductive laminate containing a first elastic cover layer, a first elastic conductive layer, an elastic dielectric layer, a second elastic conductive layer, and a second elastic cover layer in this order is contained, and the conductive material is contained. A detachable elastic capacitor characterized in that the sex laminate is detachably engaged with an elastic base material at two or more points, and the disengagement force of the engaging portion is 1 N or more and 10 N or less.
[2] The first elastic cover layer and / or the second elastic cover layer and a type III polyester load cloth (specified in Annex H of JIS L 1930 (home washing test method for textile products)). The removable stretchable capacitor according to [1], wherein the average friction coefficient is 2 or less in a dry state.
[3] The detachable expansion / contraction according to [1] or [2], wherein the 20% extension load of the conductive laminate is 20 times or less the 20% extension load of the elastic base material. Sex capacitor.
[4] The difference between the capacitance value when the detachable elastic capacitor is extended by 15% in the longitudinal direction and the capacitance value when the removable elastic capacitor is extended by 17% in the longitudinal direction is 2.5 pF or more. The removable elastic capacitor according to any one of [1] to [3].
[5] In the range where the elongation rate of the stretchable base material in the longitudinal direction is in the range of 5% to 20%, the elongation rate of the conductive laminate with respect to the elongation rate of the stretchable base material in the direction is 60% to 95%. The detachable stretchable capacitor according to any one of [1] to [4], which is characterized in that the range is in the range of [1] to [4].
[6] In the range where the elongation rate in the direction perpendicular to the longitudinal direction of the stretchable base material is in the range of 5% to 20%, the elongation rate of the conductive laminate with respect to the elongation rate of the stretchable base material in the direction is The removable stretchable capacitor according to any one of [1] to [5], which is characterized in the range of 0% to 20%.
[7] A conductive laminate containing a first elastic cover layer, a first elastic conductive layer, an elastic dielectric layer, a second elastic conductive layer, and a second elastic cover layer in this order is contained, and the conductivity is described. The conductive laminate is detachably engaged with the elastic base material at three or more points, the conductive laminate is deformed two-dimensionally, and the capacitance when the area of the conductive laminate changes by 15%. The detachable elastic capacitor according to any one of [1] to [3], wherein the difference between the value of 1 and the value of the capacitance when changed by 17% is 2.5 pF or more.

In the removable elastic capacitor of the present invention, since the conductive laminate and the elastic base material are detached by a predetermined load or more, the conductive laminate is not loaded more than expected, and the sensor is damaged due to overstretching. Does not occur. Further, since the stretchable base material does not need to have remarkable stretch anisotropy, the body movement is not hindered when the stretchable base material is used, and the materials that can be used as the stretchable base material are not limited. Further, it is possible to accurately detect the deformation in the direction to be sensed while suppressing the influence of the body movement other than the direction to be sensed, and it is possible to achieve both the degree of freedom of the body movement and the measurement accuracy.

FIG. 1 is a schematic view showing the structure of the conductive laminate used in the present invention. FIG. 2 is a schematic view showing an example of forming a detachable elastic capacitor by detachably engaging a conductive laminate and an elastic base material at two places. FIG. 3 is a schematic diagram illustrating the desorption force of the present invention. FIG. 4 is a schematic view illustrating a deformation direction of the removable elastic capacitor in the present invention. FIG. 5 is a bird's-eye view of an example of the removable elastic capacitor of the present invention from the second elastic cover layer side. FIG. 6 is a bird's-eye view from the second elastic cover layer side illustrating the shape of the third embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, those having the same reference numerals indicate the same elements, and the description thereof will be omitted as appropriate. As shown in FIG. 1, the conductive laminate 10 of the removable elastic capacitor 22 includes a first elastic cover layer 12, a first elastic conductive layer 13, an elastic dielectric layer 14, and a second elastic conductive layer. 15. The second elastic cover layer 16 is included in this order. The configuration may be included in a part of the conductive laminate 10. The conductive laminate 10 preferably further includes a detection portion 17, a waterproof cover layer 19, and an engagement portion 20. The first elastic conductive layer 13 and the second elastic conductive layer 15 penetrate through the first elastic cover layer 12 and conduct with the detection unit 17, respectively, and the detection unit 17 corresponding to the first elastic conductive layer 13 The detection unit 17 corresponding to the second elastic conductive layer 15 is insulated from each other. The through hole 18 of the first elastic cover layer 12 for the first elastic conductive layer 13 and the second elastic conductive layer 15 to penetrate is sealed with the waterproof cover layer 19. Further, as shown in FIG. 2, the conductive laminate 10 is detachably engaged with the elastic base material 11 at two or more engaging portions 20 located on the opposite surface to the detection portion 17.

The elastic base material 11 in the present invention is not particularly limited as a material, and is rubber, elastomer, nylon, polyester, polyolefin, wool, etc., and the structure is not particularly limited, and has a member having a knit structure and a woven fabric structure. A member, a member having a braided structure, a member having a cut paper structure, a member having a spiral structure, a belt member using a metal spring, and the like are shown.

The stretchable base material 11 in the present invention preferably has a stress of 20 N or less when stretched by 20%. The stress when stretched by 20% is more preferably 12N or less, further preferably 8N or less, still more preferably 5N or less, still more preferably 3N or less, because the feeling of discomfort when worn on the body is reduced. Further, the lower limit of the stress when stretched by 20% is preferably 0.1 N, more preferably 0.3 N. By setting the stress to the lower limit value or more, the fitting of the sensing wear to the body becomes good, the measurement is stable regardless of the posture, and problems such as the displacement of the sensor position do not occur.

In the present invention, the material used for engaging the conductive laminate 10 and the elastic base material 11 is not particularly limited, and the hook-and-loop fastener, buttons, magnets, self-adhesive tape, hot melt adhesive, and the like. However, it is particularly preferable to use a hook-and-loop fastener or a self-adhesive tape.

The first elastic cover layer 12 and the second elastic cover layer 16 in the present invention (hereinafter, the first elastic cover layer and the second elastic cover layer are collectively referred to simply as "elastic cover layer"). , It is preferable that it contains a resin material having elasticity, that is, a polymer material, and it is more preferable that it is made of a polymer material (resin material) having elasticity. The stretchable cover layer used in the present invention is preferably made of a stretchable insulating polymer having a tensile yield elongation of 70% or more. The tensile yield elongation is preferably 85% or more, more preferably 120% or more, still more preferably 150% or more. The upper limit is not particularly limited, but is preferably 300% or less, and more preferably 250% or less.

The tensile yield elongation in the present invention is a curve (SS) obtained by a general tensile test when the vertical axis is weighted (or strength) and the horizontal axis is strain (or elongation or elongation). In the curve), it is the elongation at the first point where an increase in elongation is observed without an increase in weight, i.e. the yield point. Generally, the yield point is regarded as a point that roughly indicates the boundary that changes from elastic deformation to plastic deformation.

The polymer material used for the elastic cover layer is preferably flexible. Examples of the flexible polymer material include an elastomer, a thermoplastic resin, a thermosetting resin, and rubber having an elastic modulus of 1 to 1000 MPa. Examples of rubber include urethane rubber, acrylic rubber, silicone rubber, butadiene rubber, nitrile group-containing rubber such as nitrile rubber and hydride nitrile rubber, isoprene rubber, sulfide rubber, styrene rubber, styrene-butadiene rubber, butyl rubber, and chlorosulfonated polyethylene. Examples include rubber, ethylene-propylene rubber, vinylidene fluoride copolymer, and the like. The elastic modulus is preferably 2 to 480 MPa, more preferably 3 to 240 MPa, still more preferably 4 to 120 MPa. The materials and structures of the first stretchable cover layer and the second stretchable cover layer may be the same or different, but are preferably industrially the same.

Examples of the flexible polymer material preferably used in the present invention include urethane rubber containing a polyether polyol or a polyester polyol as a polyol component and an HDI-based polyisocyanate as an isocyanate component.
The urethane rubber of the present invention has a high elongation rate and has a small tensile permanent strain and a small residual strain, so that it is a stretchable adhesive layer having excellent reliability when repeatedly deformed.

A hot melt adhesive may be used in the elastic cover layer in the present invention. As the hot melt adhesive in the present invention, a polymer material having a softening temperature of about 30 ° C. to 150 ° C. can be used, and preferably, it has the same degree of elasticity as the elastic dielectric layer 14. Flexible polymer materials can be used. As such a hot melt adhesive, those using an ethylene-based copolymer, a styrene-based block copolymer, a polyurethane-based, an acrylic-based copolymer, an olefin-based (co) polymer, or the like as a base polymer can be used.

In the present invention, as the stretchable cover layer, a hot melt sheet obtained by processing a polyester urethane resin having a softening temperature of 40 ° C. to 120 ° C., a polyether urethane resin, or the like into a sheet shape can be preferably used.

The first stretchable conductive layer 13 and the second stretchable conductive layer 15 in the present invention (hereinafter, the first stretchable conductive layer 13 and the second stretchable conductive layer 15 are also simply referred to as "stretchable conductive layer"). It is preferable that the specific resistance at the time of non-stretching is 3 × 10 ^{-3 Ωcm or less.} It is more preferably 1 × 10 ^-3 Ωcm or less, further preferably 3 × 10 ^-4 Ωcm or less, and even more preferably 1 × 10 ^-4 Ωcm or less. When the specific resistance is not more than this range, the variation in the resistance distribution in the conductive layer is not remarkable, the time constant of the element is small, so that the responsiveness is good, and the high frequency characteristics and the pulse responsiveness are also good. The lower limit of the specific resistance depends on the conductive material used in principle, and is, for example, 1 × 10 ^-6 Ωcm or more.

The stretchable conductive layer of the removable stretchable capacitor 22 used in the present invention preferably has a specific resistivity at 100% stretched within 100 times, more preferably 50 times or less, and further 30 times that at the time of non-stretching. It is preferably within twice, and more preferably within 15 times. When the resistivity at 100% elongation is less than this range, the resistivity distribution in the conductive layer does not become remarkable, the time constant of the element is small, so the responsiveness is good, and the high frequency characteristics and pulse responsiveness are also good. Will be. The lower limit of the specific resistance depends on the conductive material used in principle, and is, for example, 1 times or more.

The elastic conductive layer of the removable elastic capacitor 22 used in the present invention is preferably composed of at least metal particles and a flexible resin having a tensile elastic modulus of 1 MPa or more and 1000 MPa or less. The blending amount of the flexible resin is preferably 7 to 35% by mass, more preferably 10 to 30% by mass, based on the total amount of the metal particles and the flexible resin. The elastic conductive layer can be obtained by kneading and mixing metal particles and a flexible resin and molding them into a film or a sheet. The stretchable conductive layer is preferably processed into a sheet or film by coating and drying after being made into a paste or slurry for forming a stretchable conductor by adding a solvent or the like to metal particles and a flexible resin. Can be done. Further, it is also possible to give a predetermined shape by printing after making a paste.

The metal particles are preferably conductive metal particles (hereinafter, also referred to as conductive particles). The conductive particles are preferably made of a substance having a specific resistance of 1 × 10 ^-1 Ωcm or less, and more preferably made of a substance having ^{a specific resistance of 1 × 10 −2} Ωcm or less. Further, the particles having a particle diameter of 100 μm or less are preferable, and particles having a particle diameter of 50 μm or less are more preferable. Further, the particles are preferably 1 μm or more, and more preferably 5 μm or more. Examples of the substance having a specific resistance of 1 × 10 ^-1 Ωcm or less include metals, alloys, carbons, doped semiconductors, and conductive polymers. The conductive particles preferably used in the present invention include metals such as silver, gold, platinum, palladium, copper, nickel, aluminum, zinc, lead and tin, alloy particles such as brass, bronze, white copper and solder, and silver-coated copper. Hybrid grains, as well as metal-plated polymer particles, metal-plated glass particles, metal-coated ceramic particles, and the like can be used.

In the present invention, it is preferable to mainly use flake-shaped silver particles or amorphous aggregated silver powder as the conductive particles. It should be noted that the term "used mainly" here means that 90% by mass or more of the conductive particles are used. The amorphous agglomerated powder is a three-dimensional aggregate of spherical or amorphous primary particles. Amorphous agglomerated powder and flake-like powder have a larger specific surface area than spherical powder and the like, and are preferable because they can form a conductive nate work even with a low filling amount. Since the amorphous agglomerated powder is not in the form of monodisperse, it is more preferable because the particles are in physical contact with each other and easily form a conductive nate work.

Examples of the flexible resin used for the elastic conductive layer in the present invention include a thermoplastic resin, a thermosetting resin, and rubber having an elastic modulus of 1 to 1000 MPa. Urethane resin or rubber is preferable in order to develop the elasticity of the film. Examples of rubber include urethane rubber, acrylic rubber, silicone rubber, butadiene rubber, nitrile group-containing rubber such as nitrile rubber and hydride nitrile rubber, isoprene rubber, sulfide rubber, styrene rubber, styrene-butadiene rubber, butyl rubber, and chlorosulfonated polyethylene. Examples include rubber, ethylene-propylene rubber, vinylidene fluoride copolymer, and the like. Among these, nitrile group-containing rubber, chloroprene rubber, and chlorosulfonated polyethylene rubber are preferable, and nitrile group-containing rubber is particularly preferable. The range of the elastic modulus preferable in the present invention is 2 to 480 MPa, more preferably 3 to 240 MPa, still more preferably 4 to 120 MPa.

The stretchable dielectric layer in the present invention preferably contains a stretchable resin material, that is, a polymer material, and more preferably a stretchable polymer material (resin material). The stretchable dielectric layer used in the present invention is preferably made of a stretchable insulating polymer having a tensile yield elongation of 70% or more. The tensile yield elongation is preferably 85% or more, more preferably 120% or more, still more preferably 150% or more. The lower limit is not particularly limited, but is preferably 300% or less, and more preferably 250% or less.

The polymer material used for the stretchable dielectric layer is preferably flexible. Examples of the flexible polymer material include an elastomer, a thermoplastic resin, a thermosetting resin, and rubber having an elastic modulus of 1 to 1000 MPa. Examples of rubber include urethane rubber, acrylic rubber, silicone rubber, butadiene rubber, nitrile group-containing rubber such as nitrile rubber and hydride nitrile rubber, isoprene rubber, sulfide rubber, styrene-butadiene rubber, butyl rubber, chlorosulfonated polyethylene rubber, and ethylene. Examples thereof include propylene rubber and vinylidene fluoride copolymer. The elastic modulus is preferably 2 to 480 MPa, more preferably 3 to 240 MPa, still more preferably 4 to 120 MPa.

The average thickness of the stretchable dielectric layer 14 of the present invention is 0.3 from the viewpoint of increasing the capacitance C to improve the detection sensitivity and improving the followability to the object to be measured. It is preferably in the range of ~ 1000 μm, preferably in the range of 0.4 to 100 μm from the viewpoint of sensitivity, further preferably in the range of 0.5 to 70 μm, and further preferably in the range of 0.6 to 50 μm.

The elastic dielectric layer 14 used in the present invention preferably has a relative permittivity of 2.2 or more when no load is applied, more preferably 2.8 or more, still more preferably 3.4 or more, and 3.8 or more. The above is still preferable. The upper limit of the relative permittivity is about 500, preferably 150 or less, and more preferably 80 or less. For the purpose of the present invention, it is preferable that the elastic dielectric layer 14 has a high relative permittivity, but in general, a polymer material having elasticity often has an alkyl group in the flexible chain component and is relatively low. It has a relative permittivity. In the present invention, it is preferable to increase the relative permittivity by introducing a polar group into the molecular chain. A nitrile group, a ketone group, an ester group, a halogen substituent, a hydroxyl group, a carboxyl group, a nitro group, a halogen group and the like are functional groups effective for increasing the relative permittivity of a polymer.

It is possible to increase the relative permittivity of the stretchable dielectric layer 14 by adding a filler having a high relative permittivity, preferably an inorganic filler such as titanate, to the stretchable dielectric layer 14. The relative permittivity of the inorganic filler is preferably less than 5. When the stretchable dielectric layer 14 is stretched or compressed, the degree of stress concentration on the stretchable polymer portion is reduced and peeling does not occur at the interface between the inorganic filler and the resin. Therefore, the relative permittivity of the inorganic filler is high. It is more preferably 4 or less, still more preferably 3 or less. The content of the inorganic filler in the stretchable dielectric layer 14 is preferably 10% by mass or more, more preferably 20% by mass or more. Further, it is preferably 80% by mass or less, more preferably 70% by mass or less. On the other hand, the content of the inorganic filler having a relative permittivity of 5 or more in the stretchable dielectric layer 14 is preferably 10% by mass or less. The content of the inorganic filler having a relative permittivity of 5 or more is preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.3% by mass or less. When the content of the inorganic filler having a relative permittivity of 5 or more is large, the degree of stress concentration on the stretchable polymer portion increases when the stretchable dielectric layer 14 is stretched or compressed, and the interface between the filler and the resin is high. Durability may be problematic, such as peeling and formation of voids. Further, if the amount of the inorganic filler contained in the stretchable dielectric layer 14 is large, the Poisson's ratio of the stretchable dielectric layer 14 becomes low, the change in capacitance during stretching becomes small, and the sensitivity when applied as a sensor is lowered. I have something to do.

It is essential that the disengagement force between the conductive laminate 10 and the engaging portion 20 of the elastic base material 11 in the present invention is 1N or more and 10N or less, preferably 2N or more and 8N or less, and more preferably 3N or more and 6N or less. Is. When the disengagement force of the engaging portion 20 is 1N or more, the conductive laminate can be sensed without being disengaged from the elastic base material by a slight impact or operation. On the other hand, when the desorption force is 10 N or less, when the elastic base material is stretched more than expected, the conductive laminate is stretched following without desorption, and the conductive layer is damaged by overstretching. It can be prevented from occurring. The number of engaging portions may be two or more. The number of engaging portions is preferably 3 points or more, and more preferably 4 points or more, because it is easy to prevent disengagement due to a slight impact or operation. The upper limit is not particularly limited, but is preferably 20 points or less, more preferably 10 points or less, and further preferably 5 points or less from the viewpoint of cost.

Here, the desorption force is shown in FIG. 3 when 180 degree peeling specified in JIS K6854-2 (1999) is performed on the engaging portion between the conductive laminate and the elastic base material. Defined as maximum test force. In the engaging part between the conductive laminate and the stretchable base material, the conductive base material and the stretchable base material are set on the chuck of the tensile tester, and the chuck is moved at 100 mm / min to obtain the maximum test force. Continues to grow. If the conductive laminate or elastic substrate breaks before the maximum test force is obtained, reinforce it with a hot melt sheet, double-sided tape, gum tape, etc., if necessary. The disengagement force of the engaging portion means the disengagement force of all the engaging portions.

The first stretchable cover layer 12 and / or the second stretchable cover layer 16 in the present invention is a type III polyester load cloth (specified in Annex H of JIS L 1930 (home washing test method for textile products)). The average coefficient of friction of the above is preferably 2 or less in a dry state. Since the first elastic cover layer 12 is located on the outermost layer of the conductive laminate 10, the stickiness is small in consideration of ease of handling. The average friction coefficient in a dry state is more preferably 1.5 or less, and more preferably 1 or less, because stickiness is small and handling and storage are easy when the average friction coefficient is 2 or less. It is more preferable. Since the average friction coefficient in the dry state is preferably small, the lower limit is not particularly limited, but if it is 0.1 or more, no stickiness is felt, and 0.2 or more may be used. The average coefficient of friction of either the first stretchable cover layer 12 or the second stretchable cover layer 16 is preferably within the above range, and more preferably both are within the above range.

Here, the type III polyester load cloth is specified in Annex H of JIS L 1930 (2014) (Home washing test method for textile products), but it is replenished to be added to the washing machine together with the sample so as to have the specified weight. It is a cloth and is a knitted fabric made of 100% polyester.
The average coefficient of friction is when two types of samples are in contact with each other with a constant load, one sample is fixed, and the other sample is moved at a constant speed for a certain distance, the sample is hung on the fixed sample side. It is calculated from the integrated value of the load. The dry state is preferably a state in which the water content of each layer is 20% by mass or less, more preferably 15% by mass or less, and further preferably 12% by mass in an environment of a temperature of 20 ° C. and a humidity of 65% RH. It is in the following state.

It is preferable that the 20% elongation load of the conductive laminate 10 in the present invention is 5 times or more and 20 times or less the 20% elongation load of the elastic base material 11. It is more preferably 6 times or more, and further preferably 7 times or more. Further, it is more preferably 19 times or less, and further preferably 18 times or less. By setting it within the above range, when the removable elastic capacitor 20 is arranged in the portion to be measured in the clothes mold, the force applied to the shrinkage direction of the conductive laminate can be reduced, which corresponds to the conductive laminate. It is possible to suppress the feeling of discomfort when wearing the part.

The difference between the capacitance value when the detachable elastic capacitor 22 in the present invention is extended by 15% in the longitudinal direction and the capacitance value when the removable elastic capacitor 22 is extended by 17% in the longitudinal direction is 2.5 pF or more. Is preferable, and 3 pF or more is more preferable. As shown in FIGS. 4A and 4B, when the conductive laminate 10 and the elastic base material 11 have two engaging portions 20, the longitudinal direction connects the centers of gravity of the engaging members to each other. The direction. As shown in FIG. 4C, when the conductive laminate 10 and the elastic base material 11 have three or more engaging portions 20 and the conductive laminate 10 is two-dimensionally deformed, the conductive laminate 10 is deformed two-dimensionally. It is preferable that the change in the capacitance value when the area of the body 10 changes by 15% and when the area changes by 17% is 2.5 pF or more. Since the capacitance value is easily affected by noise depending on the measurement environment, it is required to increase the S / N ratio, especially when measuring minute deformation such as respiration of the human body. By setting the capacitance value to 2.5 pF or more within the range of the elongation rate, the change in capacitance due to minute deformation is not buried in the change in capacitance due to noise. Therefore, the sensing ability can be maintained. The upper limit of the difference between the capacitance values is not particularly limited, but is preferably 10 times or less, more preferably 8 times or less, and particularly preferably 5 times or less.

In the range where the elongation rate of the stretchable base material 11 in the longitudinal direction in the present invention is in the range of 5% to 20%, the elongation rate of the conductive laminate 10 with respect to the elongation rate of the stretchable base material 11 in the direction is 60% to 95%. It is preferably in the range of. The elongation response of the conductive laminate 10 to the stretchable base material 11 is good, and the performance of sensing deformation is also good. Therefore, it is more preferably 65% or more, still more preferably 70% or more. Further, while improving the elongation response of the conductive laminate 10 to the elastic base material 11, it suppresses the detection of signals that are not originally desired like other body movements during the respiration measurement of the human body, and has good detection accuracy. Therefore, it is more preferably 90% or less, and further preferably 85% or less.

In the range where the elongation rate in the direction perpendicular to the longitudinal direction of the stretchable base material 11 in the present invention is in the range of 5% to 20%, the elongation of the conductive laminate 10 with respect to the elongation rate of the stretchable base material 11 in the direction concerned. The rate is preferably in the range of 0% to 20%. A more preferable range of the upper limit is 19% or less, still more preferably 18% or less. Since it becomes difficult to detect noise, it is preferable that the elongation rate is low, and the lower limit is not particularly limited, but industrially, it may be 1% or more, and may be 2% or more. By setting it within the above range, the detection of deformation other than the originally desired direction is suppressed, and the measurement accuracy is improved. For example, when the purpose is to measure the respiration of the human body, only the deformation of the chest and abdomen due to respiration can be detected, and other body movements that cause noise are not detected.

Since the removable elastic capacitor 22 of the present invention causes a change in capacitance due to tensile deformation, it is possible to detect pressure, strain, displacement, degree of deformation, and the like by utilizing this. By attaching the removable telescopic condenser 22 to the chest or abdomen, it is possible to measure respiration from the displacement of the chest and abdomen, and by attaching it to joints such as elbows and knees, it is also possible to apply it to motion capture. .. Further, in the stretchable capacitor 22 in the present invention, since the conductive laminate 10 and the stretchable base material 11 are separated from each other by a predetermined load or more, the conductive laminate 10 is not loaded more than expected, and the conductive laminate 10 is not overstretched. No sensor damage occurs. Since the elastic base material 11 and the conductive laminate 10 are separated and stretched, it is possible to suppress effects other than stretching in the direction to be detected. Further, at this time, since the stretchable base material does not need to have a remarkable stretch anisotropy, the body movement is not hindered when the stretchable base material is used, and it is possible to achieve both the degree of freedom of body movement and the measurement accuracy. ..

Hereinafter, the present invention will be specifically described with reference to Examples.
<Elastic modulus>
The sample to be measured was formed into a sheet having an arbitrary thickness in the range of 20 μm to 200 μm, and then punched into a dumbbell mold specified by ISO 527-2-1A to obtain a test piece. A tensile test was performed by the method specified in ISO 527-1 to obtain a stress-strain diagram of the resin material, and the elastic modulus was calculated by a conventional method.

<Tension yield elongation>
The sample to be measured was formed into a sheet having an arbitrary thickness in the range of 20 μm to 200 μm, and then punched into a dumbbell mold specified by ISO 527-2-1A to obtain a test piece. Then, the SS curve was obtained using a tensile tester, and the elongation at the yield point was defined as the tensile yield elongation.

<Specific resistivity>
If the conductor sheet is large enough, punch it into a dumbbell type specified by ISO 527-2-1A, and use the 10 mm wide and 80 mm long part in the center of the dumbbell type test piece as the test piece. Using. When the conductor sheet can be molded, it is heat-compressed into a sheet having a thickness of 200 ± 20 μm, and then punched into a dumbbell mold specified by ISO 527-2-1A to obtain a test piece in the same manner. If the size of the conductor sheet was too small to obtain the specified dumbbell shape, a rectangle with a recoverable width and length was cut out and used as a test piece, and the width and thickness measured were used for conversion. ..
Test piece: Measure the resistance value [Ω] of the part with a width of 10 mm and a length of 80 mm using a milliohm meter manufactured by Agilent Technologies, and multiply by the aspect ratio (1/8) of the test piece to obtain the sheet resistance value “Ω]. □ ”was asked. Further, the resistivity value [Ω] was multiplied by the cross-sectional area (width 1 [cm] mm × thickness [cm]) and divided by the length (8 cm) to obtain the specific resistance [Ωcm].

<Average coefficient of friction>
The type III polyester load cloth (specified in Annex H of JIS L 1930 (home washing test method for textile products)) was cut into a width of 10 mm and a length of 20 mm. KES-SE (manufactured by Kato Tech) sample stand. A type III polyester load cloth attached to the grinder is placed on the sample to be measured, and a type III polyester load cloth attached to the grinder is brought into contact with the sample to be measured, and a load of 25 gf is applied. The average friction coefficient MMD was obtained from the measurement results of 20 mm excluding 5 mm at both ends after moving 30 mm at a sensitivity H and a sample moving speed of 1 mm / s.

<Extended load>
The conductive laminate and elastic base material were sandwiched between chucks at a distance of 50 mm between chucks, the chucks were moved at a speed of 300 mm / min, and the load when extended to 60 mm was measured and used as the 20% extended load. .. If the distance between chucks cannot be 50 mm depending on the sample, there is no need to be particular about this. In that case, the chuck was chucked at a possible distance, and the load when extended by 20% with respect to the distance was defined as the load when extended by 20%.

<Elongation rate>
The elastic base material was sandwiched between the chucks of the tensile tester outside the engaging portion of the removable elastic capacitor, and the chuck was moved at a speed of 300 mm / min. The length of the conductive laminate when stretched by 5% or 20% with respect to the distance between the chucks was measured, and the elongation ratio with respect to the length of the conductive laminate at the time of unstretching was determined.

<Specific resistance>
If the conductor sheet is large enough, punch it into a dumbbell type specified by ISO 527-2-1A, and use the 10 mm wide and 80 mm long part in the center of the dumbbell type test piece as the test piece. Using. When the conductor sheet can be molded, it is heat-compressed into a sheet having a thickness of 200 ± 20 μm, and then punched into a dumbbell mold specified by ISO 527-2-1A to obtain a test piece in the same manner. If the size of the conductor sheet is too small to obtain the specified dumbbell shape, cut out a rectangle with a width and length that can be collected, use it as a test piece, and use the measured width, thickness, and length. Converted.
Test piece: Measure the resistance value [Ω] of the part with a width of 10 mm and a length of 80 mm using a milliohm meter manufactured by Agilent Technologies, and multiply by the aspect ratio (1/8) of the test piece to obtain the sheet resistance value “Ω]. □ ”was asked.
Further, the resistivity value [Ω] was multiplied by the cross-sectional area (width 1 [cm] mm × thickness [cm]) and divided by the length (8 cm) to obtain the specific resistance [Ωcm].

<Relative permittivity>
The relative permittivity of the stretchable conductor sheet was measured under the conditions of a temperature of 23 ° C. and a frequency of 1 GHz by a cavity resonator perturbation method (network analyzer (manufactured by Anritsu)).

<Sensing>
Sensing was judged by the following evaluation criteria.
⊚: 80% or more of the total expansion / contraction operation can be detected by the change in capacitance.
◯: 60% or more and less than 80% of the total expansion / contraction operation can be detected by the change in capacitance.
X: Of all the expansion and contraction operations, less than 60% could be detected by the change in capacitance.

<Uncomfortable wearing>
The feeling of discomfort in wearing was judged by the following evaluation criteria.
⊚: The subjective evaluation of the feeling of tightening and the feeling of tension was carried out on a 5-point scale, and the evaluation when no discomfort was 5 was 4 or more.
◯: A five-level subjective evaluation was performed on the feeling of tightening and the feeling of tension, and the evaluation was 3 when no discomfort was set to 5.
X: A five-level subjective evaluation was performed on the feeling of tightening and the feeling of tension, and the evaluation was 2 or less when no discomfort was set to 5.

<Storage / handling>
Storage and handleability were judged according to the following evaluation criteria.
⊚: No stickiness or sticking occurs even after stacking and storing two or more removable elastic capacitors at room temperature.
◯: After stacking and storing two or more removable elastic capacitors at room temperature, stickiness does not occur although it is sticky.
X: Stickiness and sticking occur after stacking and storing two or more removable elastic capacitors at room temperature.

<Sensor damage>
Sensor damage was determined by the following evaluation criteria.
⊚: No abnormality occurs in the change in capacitance at the time of 50% elongation.
◯: When the elongation is 30% or more and less than 50%, the linearity of the change in capacitance with respect to the elongation is impaired.
X: When the elongation is 10% or more and less than 30%, the linearity of the change in capacitance with respect to the elongation is impaired.

[Example 1]
12 parts by mass of nitrile butadiene rubber having 40% by mass of nitrile, 46 parts by mass of Mooney viscosity 46, 30 parts by mass of isophorone, and 58 parts by mass of fine flake-shaped silver powder [trade name Ag-XF301 manufactured by Fukuda Metal Foil Powder Industry Co., Ltd.] with an average particle diameter of 6 μm. The paste AG1 for forming an elastic conductive layer was obtained by uniformly mixing and dispersing with a three-roll mill. The obtained stretchable conductive layer forming paste AG1 was applied and dried in the form of a release PET film by a screen printing method to obtain a stretchable conductor sheet having a thickness of 22 μm.

The obtained stretchable conductor sheet was cut into a width of 10 mm and a length of 200 mm, and the specific resistance was obtained from the resistance value and the thickness in the length direction. As a result, the resistivity was 1.0 × 10 ^-4 Ωcm. Next, clip both ends of the stretchable conductor sheet in the length direction between the clips of the pull tester, pull it to 320 mm with an effective length of 160 mm, and determine the resistivity at both ends, the width and thickness of the narrowest part of the test piece. It was used to calculate the specific resistance at 100% elongation. As a result, the resistivity at 100% elongation was 48 × 10 ^-4 Ωcm.

30 parts by mass of NBR (nitrile butadiene rubber) having an amount of nitrile of 40% by mass and a Mooney viscosity of 46 was dissolved in 40 parts by mass of isophorone to obtain a stretchable dielectric layer forming paste CC1.

30 parts by mass of NBR (nitrile butadiene rubber) having an amount of nitrile of 40% by mass and a Mooney viscosity of 46 was dissolved in 40 parts by mass of isophorone to obtain a paste CC2 for forming a first elastic cover layer.

30 parts by mass of NBR (nitrile butadiene rubber) having an amount of nitrile of 40% by mass and a Mooney viscosity of 46 was dissolved in 40 parts by mass of isophorone to obtain a second stretchable cover layer forming paste CC3.

Using the screen printing method on the release PET film, the previously obtained paste CC2 for the first elastic cover layer was applied and dried to obtain a first elastic cover layer having a width of 30 mm, a length of 200 mm and a thickness of 35 μm. .. Next, the paste AG1 for forming the elastic conductive layer was applied and dried on the first elastic cover layer by a screen printing method to obtain a first elastic conductive layer having a thickness of 30 μm. As for the shape, as shown in FIG. 5, a rectangular portion having a width of 10 mm and a length of 150 mm and a bent portion of 10 mm square were provided. Next, the stretchable dielectric layer forming paste CC1 was applied and dried on the first stretchable conductive layer by a screen printing method to obtain a stretchable dielectric layer having a width of 30 mm, a length of 200 mm and a thickness of 35 μm. Next, the stretchable conductive layer forming paste AG1 was applied and dried on the stretchable dielectric layer by a screen printing method to obtain a second stretchable conductive layer having a thickness of 30 μm. The shape is the same as the first conductive layer, which has a rectangular part with a width of 10 mm and a length of 120 mm and a bent part of 10 mm square. I tried not to overlap. Next, the paste CC3 for forming the second elastic cover layer was applied and dried on the second elastic conductive layer by a screen printing method to obtain a second elastic cover layer having a width of 30 mm, a length of 200 mm and a thickness of 35 μm. rice field. Next, a spring hook button was driven into each of the bent portions of the first elastic conductive layer and the second elastic conductive layer, and a detection unit capable of detecting a signal from above the second elastic cover layer was provided. Further, male members (two) of hook-and-loop fasteners were attached to both ends of the first elastic cover layer with a hot melt adhesive to obtain a conductive laminate.

Average friction between the first elastic cover layer and the second elastic cover layer of the conductive laminate and the type III polyester load cloth (specified in Annex H of JIS L 1930 (home washing test method for textile products)). The coefficients were measured and listed in Table 1.

When a tensile test was performed on the rectangular portions of the first elastic conductive layer and the second elastic conductive layer of the conductive laminate and the chucks were stretched at a distance between chucks of 50 mm, an elongation rate of 0% to 25%, and an elongation rate of 10 mm / s. The load at the time of 20% extension was measured.

A knit fabric made of nylon / polyester was selected as the elastic base material, and a tensile test was performed on the knit fabric. Table 1 shows the results of calculating the 20% elongation load of the conductive laminate with respect to the 20% elongation load of the stretchable base material. Further, in the elastic base material, a female hook-and-loop fastener was attached at a position corresponding to the hook-and-loop fastener position of the conductive laminate.

The conductive laminate and the elastic base material were engaged with each other at the position of the hook-and-loop fastener, and the disengagement force of the engaging portion was measured and shown in Table 1.

The conductive laminate and the elastic base material are engaged at the position of the surface fastener, and while being stretched by the tensile tester, the first elastic conductive layer and the second elastic conductive layer are used by the LCR high tester manufactured by Hioki Electric Co., Ltd. A lead wire was connected to the detection unit corresponding to each layer, and the capacitance was measured at a measurement frequency of 1 GHz. When only the elastic base material 5 mm outside the engaging part of the conductive laminate is chucked and stretched at a chuck distance of 210 mm, an elongation rate of 0% to 25%, and an elongation rate of 10 mm / s, the elongation rate is 15%. The difference in capacitance value at 17% was calculated and shown in Table 1. The extension direction at this time is the direction in which the centers of gravity of the engaging members are connected to each other.

The conductive laminate and the stretchable base material are engaged with each other at the position of the hook-and-loop fastener, and while the stretchable base material is stretched by a tensile tester, the stretchable base material is stretched by 5% or 20%. The elongation rate with respect to the above was calculated and shown in Table 1. At this time, only the elastic base material 5 mm outside from the engaging portion of the conductive laminate was chucked, and stretched at a distance between the chucks of 210 mm, an elongation rate of 0% to 25%, and an elongation rate of 10 mm / s. The extension direction at this time is the direction in which the centers of gravity of the engaging members are connected to each other.

The conductive laminate and the stretchable base material are engaged with each other at the position of the hook-and-loop fastener, and while the stretchable base material is stretched by a tensile tester, the stretchable base material is stretched by 5% or 20%. The elongation rate with respect to the above was calculated and shown in Table 1. At this time, only the elastic base material 5 mm outside from the engaging portion of the conductive laminate was chucked, and stretched at a distance between the chucks of 40 mm, an elongation rate of 0% to 25%, and an elongation rate of 10 mm / s. The extension direction at this time is a direction perpendicular to the direction in which the centers of gravity of the engaging members are connected to each other.

A compression type garment was made of elastic substrate and a female hook-and-loop fastener was attached to the chest position so that the conductive laminate could be engaged. A 30-year-old healthy man was made to wear this garment with a conductive laminate engaged, and the respiratory state when the first radio exercise was performed was measured. As for the respiratory state, the change in chest circumference was captured as a change in capacitance with a removable elastic capacitor. To detect the capacitance, a small measuring instrument was attached to the detection unit installed on the conductive laminate, and the measurement results were wirelessly transmitted to the android terminal and stored. As a result, the subject exercised without feeling any discomfort, and was able to accurately measure the respiratory waveform while there was physical movement in radio calisthenics. In addition, when the detachable elastic capacitor was stored and used again for measurement, stickiness did not occur and the handling was good.

[Example 2]
A removable stretchable capacitor was obtained by operating in the same manner as in Example 1 except that a urethane resin was used as the stretchable cover layer and a magnet was used for the engaging portion between the conductive laminate and the stretchable base material. The evaluation results are shown in Table 1.
The obtained removable elastic capacitor was attached to the chest of a short-sleeved shirt using a stretch material, and sensing wear was obtained in the same manner. The obtained sensing wear was worn by a healthy 30-year-old man, and the respiratory state when the first radio exercise was performed by the same method as in Example 1 was measured. As a result, the subject exercised without feeling any discomfort, and was able to accurately measure the respiratory waveform while there was physical movement in radio calisthenics. In addition, when the detachable elastic capacitor was stored and used again for measurement, stickiness did not occur and the handling was good.

[Example 3]
A detachable elastic capacitor was obtained by operating in the same manner as in Example 1 except for the shape of the conductive laminate. The shape is shown in detail in FIG. 6, and the first elastic cover layer, the elastic dielectric layer, and the second elastic cover layer have a square shape of 40 mm square. In the first stretchable conductive layer and the second stretchable conductive layer, a 20 mm square shaped portion overlaps in the thickness direction, and a 5 mm square protruding portion does not overlap in the thickness direction. The evaluation results are shown in Table 1.
The obtained detachable elastic capacitor was engaged with the elbow joint of a shirt made of a stretch material, and was worn by a healthy 30-year-old man to sense the movement of the arm when the first radio exercise was performed. As a result, the subject was able to measure the angle when the elbow was bent without feeling any discomfort. In addition, when the detachable elastic capacitor was stored and used again for measurement, stickiness did not occur and the handling was good.

[Example 4]
A detachable elastic capacitor was obtained by operating in the same manner as in Example 1 except for the portion where natural rubber was used for the first elastic cover layer. The evaluation results are shown in Table 1.
The obtained removable elastic capacitor was attached to the chest of a short-sleeved shirt using a stretch material to obtain sensing wear. The obtained sensing wear was worn by a healthy 30-year-old man, and the respiratory state when the first radio exercise was performed by the same method as in Example 1 was measured. As a result, the subject felt a little uncomfortable with the detachable elastic capacitor part, but there was almost no problem, and the measurement accuracy of the respiratory waveform was also almost no problem. After that, when the removable elastic capacitor was stored and used for measurement again, the cover layer was slightly sticky, but the phenomenon such as sticking between the cover layers did not occur, and there was no problem in handling.

[Comparative Example 1]
An acrylic resin was used for the stretchable dielectric layer, and a detachable stretchable capacitor was obtained by operating in the same manner as in Example 1 except for the portion where the spring hook button was used for the engaging member. The evaluation results are shown in Table 1.
The obtained removable elastic capacitor was attached to the chest of a short-sleeved shirt using a stretch material to obtain sensing wear. The obtained sensing wear was worn by a healthy 30-year-old man, and the respiratory state when successful at 16 km / h was measured using a treadmill. As a result, the respiratory waveform could not be distinguished from noise, and accurate sensing could not be performed. After that, the measurement was tried again with a removable elastic capacitor, but it showed a tendency of scratches in which the capacitance value became an abnormal value. This is because the desorption force of the engaging portion between the conductive laminate and the elastic base material is high, so that the conductive laminate is desorbed from the elastic base material even though a force exceeding expectations is applied to the conductive laminate. It is considered that the damage was caused by the overstretching of the conductive laminate.

[Comparative Example 2]
A urethane resin is used for the first elastic cover layer, an acrylic resin is used for the second elastic cover layer, and a magnet is used for the engaging member. Obtained a stretchable capacitor. The evaluation results are shown in Table 1.
The obtained removable elastic capacitor was attached to the chest of a short-sleeved shirt using a stretch material to obtain sensing wear. The obtained sensing wear was worn by a healthy 30-year-old man, and the respiratory state when the first radio exercise was performed by the same method as in Example 1 was measured. As a result, the respiratory waveform was affected by the body movements of radio calisthenics, and some breaths could not be detected, and accurate sensing could not be performed. In addition, since the desorption force between the conductive laminate and the elastic base material was low, desorption occurred frequently during radio exercises, and measurement was frequently interrupted.

As described above, the detachable elastic capacitor of the present invention accurately detects the deformation that is originally desired to be detected while ensuring free body movement, and even when the sensor is loaded more than expected, the sensor is used. Since it is less likely to be damaged, it is useful as a sensor element to be attached to clothing or the like.

10. Conductive laminate 11. Elastic base material 12. First elastic cover layer 13. First elastic conductive layer 14. Elastic dielectric layer 15. Second elastic conductive layer 16. Second elastic cover layer 17. Detection unit 18. Through hole 19. Waterproof cover layer 20. Engagement part 21. 2. A portion where the first elastic conductive layer and the second elastic conductive layer overlap in the thickness direction. Detachable elastic capacitor

Claims (7)

The conductive laminate containing the first elastic cover layer, the first elastic conductive layer, the elastic dielectric layer, the second elastic conductive layer, and the second elastic cover layer in this order is contained. Is a detachable elastic capacitor characterized in that it engages detachably with an elastic base material at two or more points and the disengagement force of the engaging portion is 1 N or more and 10 N or less. Average coefficient of friction between the first stretchable cover layer and / or the second stretchable cover layer and a type III polyester load cloth (specified in Annex H of JIS L 1930 (Home Washing Test Method for Textile Products)). The removable stretchable capacitor according to claim 1, wherein the capacitor is 2 or less in a dry state. The removable elastic capacitor according to claim 1 or 2, wherein the 20% elongation load of the conductive laminate is 20 times or less the 20% elongation load of the elastic substrate. The feature is that the difference between the value of the capacitance when the detachable elastic capacitor is extended by 15% in the longitudinal direction and the value of the capacitance when the capacitor is extended by 17% in the longitudinal direction is 2.5 pF or more. The removable elastic capacitor according to any one of claims 1 to 3. The elongation rate of the stretchable substrate in the longitudinal direction is in the range of 5% to 20%, and the elongation rate of the conductive laminate with respect to the elongation rate of the stretchable substrate in the direction is in the range of 60% to 95%. The removable elastic capacitor according to any one of claims 1 to 4, wherein the capacitor is provided. In the range where the elongation rate in the direction perpendicular to the longitudinal direction of the elastic substrate is in the range of 5% to 20%, the elongation rate of the conductive laminate with respect to the elongation rate of the elastic substrate in the direction is from 0%. The removable stretchable capacitor according to any one of claims 1 to 5, characterized in that it is in the range of 20%. The conductive laminate containing the first elastic cover layer, the first elastic conductive layer, the elastic dielectric layer, the second elastic conductive layer, and the second elastic cover layer in this order is contained. Is detachably engaged with the elastic base material at three or more points, the conductive laminate is deformed two-dimensionally, and the value of the capacitance when the area of the conductive laminate changes by 15%. The removable stretchable capacitor according to any one of claims 1 to 3, wherein the difference in the value of the capacitance when the change is 17% is 2.5 pF or more.

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