JP2018183964A - Knit with conductive layer, strain sensor, and wearable sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a knit with a conductor layer capable of detecting a resistance value variation while having comfortable wearing feeling a knit possesses, and hard to disconnect the conductor layer even if the knit expands.SOLUTION: A knit 10 with a conductor layer is obtained by laminating a conductive layer 13 on a knit 12. The knit 12 is obtained by knitting with a twisted yarn obtained by twisting a plurality of single yarns. The conductive layer 13 is expandable, generates a resistance value variation, and is formed along such a direction that a longitudinal direction of the conductive layer 13 continues a surface layer F of the knit 12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a knit with a conductive layer, which is a knit (knitted fabric) provided with a conductive layer, and a strain sensor and a wearable sensor using the knit with the conductive layer.

  In recent years, sensors for measuring body conditions such as pulse and movement have been installed, and wearable devices such as smart watches, activity meters, and pulse meters have been actively developed, but conventional wearable devices are rigid boards. In many cases, a unit in which a semiconductor element is arranged and a conductive circuit is formed is used. However, a wearable device using a rigid substrate is hard and does not follow the movement of the body, so a comfortable wearing feeling cannot be obtained. Therefore, a technique for obtaining a flexible wearable device by forming a conductive circuit on an elastic body or clothing has been developed. Such techniques include, for example, Japanese Unexamined Patent Application Publication No. 2006-076531 (Patent Document 1), Japanese Unexamined Patent Application Publication No. 2005-137456 (Patent Document 2), Japanese Unexamined Patent Application Publication No. 2000-148290 (Patent Document 3), International Publication 2016 /. No. 114339 (Patent Document 4).

JP 2006-076531 A JP 2005-137456 A JP 2000-148290 A International Publication No. 2016/114339

  According to Japanese Patent Laying-Open No. 2006-076531 (Patent Document 1), a wearable housing made of an elastomer in which a wiring layer is disposed is disclosed, and “it has a simple structure and can be applied to a wearable terminal or the like. A composite module having excellent impact properties and high reliability "(see paragraph [0018]) is obtained. Japanese Patent Laid-Open No. 2005-137456 (Patent Document 2) discloses a body-worn electrode device in which a circuit is printed on one surface of a base film provided with a cleavage induction portion. Thus, the electrode mounting position can be adjusted easily and accurately, and even if the patient has been wearing for a long time, there is little discomfort ”(see paragraph [0020]). However, a wearable device composed of an elastomer or a resin film as a base material is not necessarily comfortable when used for a long time because the base material does not absorb sweat and does not have air permeability.

  On the other hand, in Japanese Patent Laid-Open No. 2000-148290 (Patent Document 3), a shirt is formed by “twisting a plurality of super fine conductors into a sewing thread or weaving super fine conductors into a fabric itself” (see paragraph [0033]). And forming network wiring on clothes such as trousers. When a circuit is formed on the fabric using conductive yarns as described above, the fabric has sweat absorbency and breathability, so it is considered comfortable even when used for a long time.

  However, the technique described in Japanese Patent Laid-Open No. 2000-148290 (Patent Document 3) has the following problem. First, the formation of a complicated circuit is costly because the circuit sewing process takes a long time. Secondly, conductive yarns have relatively high conductivity, but there are problems with the stretchability of the yarn itself, so stretchable stitches using zigzag stitching or overlock sewing machines for stretching applications. Must be formed. Such a seam requires a certain stitch width (area) and is not suitable for forming a complicated circuit. In addition, since the yarn itself is not stretched, it does not show a change in resistance value due to stretching and cannot be used as a sensor.

  On the other hand, International Publication No. 2016/114339 (Patent Document 4) describes the role of a stretch stopper in order to solve the problem that a wiring is cracked when clothes formed with a conductive polymer or silver paste are stretched. (See paragraphs [0017] [0021]). However, by suppressing the elongation, not only does the stress for stretching increase and the wearing feeling is impaired, but the range of use as a sensor is limited. In addition, the technology for suppressing elongation did not improve the elongation rate at which cracks occur.

  In other words, fabrics such as clothing have good breathability and good wearing feeling compared to wearable devices composed of elastic materials such as elastomer and resin film among flexible wearable devices. Since there are irregularities and holes, it is difficult to form a conductive layer, and the conductive layer is easily disconnected when the fabric is stretched, and no suitable technique has been obtained for solving this problem.

  Therefore, the present invention provides a knit with a conductive layer that can detect a change in resistance value while having a comfortable wearing feeling provided by the knit, and the conductive layer is not easily disconnected even when the knit is stretched, and a strain sensor using the knit. A wearable sensor is provided.

  In order to achieve the above object, the present invention is configured as follows. That is, the present invention is a knit with a conductive layer in which a conductive layer is laminated on a knit, wherein the knit is knitted by a twisted yarn twisted by a plurality of single yarns, and the conductive layer is stretchable. There is provided a knit with a conductive layer which causes a change in resistance value due to stretching and is formed along a direction in which the longitudinal direction of the conductive layer is continuous with a surface layer portion of the knit.

  Since it is a knit with a conductive layer in which a conductive layer is laminated on a knit, it is possible to obtain a comfortable product having knit elasticity, flexibility, and moisture retention by using a knit as a base material. Further, since the knit is knitted with a twisted yarn of a plurality of single yarns, the conductive layer can be immersed in the gaps between the single yarns, and the conductive layer has excellent adhesion to the knit. it can.

  Since the conductive layer is stretchable and causes a change in resistance value due to stretching, the resistance value of the conductive layer can be detected, and the degree of expansion of the conductive layer can be estimated from the change in the resistance value. Moreover, since the longitudinal direction of the conductive layer is formed along the direction in which the surface layer portion of the knit continues, the conductive layer is not easily broken by the extension of the knit.

  The conductive layer may be a knit with a conductive layer that penetrates at a depth of 10 to 50% of the thickness of the twisted yarn on the twisted yarn of the surface layer portion of the knit. Since the conductive layer is infiltrated onto the twisted yarn of the surface layer portion of the knit at a depth of 10 to 50% of the thickness of the twisted yarn, the conductive layer does not easily peel off from the knit and is not easily broken by the knit extension. be able to.

  The conductive layer may be a knit with a conductive layer, which is a cured body of a conductive paste in which conductive powder is dispersed in a crosslinked rubber or a thermoplastic elastomer. Since the conductive layer is a cured body of a conductive paste in which conductive powder is dispersed in a crosslinked rubber or a thermoplastic elastomer, the conductive layer can be formed on the knit surface by printing the conductive paste. Moreover, it can be set as the electrically conductive layer from which resistance value changes by extending.

  The knit is at least one knit selected from flat knitting, rubber knitting, or any one or a combination thereof, and a knit with a conductive layer in which a longitudinal direction of the conductive layer is a wale direction of the knit. can do. Since the knit is at least one knit selected from flat knitting, rubber knitting, or any one or a combination thereof, and the wale direction of the knit is formed as the longitudinal direction of the conductive layer, the knit on such a knit is formed. It can be set as the knit with a conductive layer which has a conductive layer which does not break easily even if it extends | stretches.

  The knit may be at least one knit selected from pearl knitting or any one or a combination thereof, and the conductive layer may be a knit with a conductive layer in which the longitudinal direction of the conductive layer is the course direction of the knit. . Since the knit is at least one knit selected from pearl knitting or any one or a combination thereof, and the course direction of the knit is formed as the longitudinal direction of the conductive layer, the knit is stretched on such a knit. Also, a knit with a conductive layer having a conductive layer that is difficult to break can be obtained.

  The knit is at least one knit selected from a 2-way tricot or any one or a combination thereof, and the conductive layer is provided on a sinker surface, the longitudinal direction of which is the wale direction of the knit Or the conductive layer is provided on the needle surface, and the knit with the conductive layer whose longitudinal direction is the course direction of the knit can be provided. The knit is at least one knit selected from two-way tricot or any one or a combination thereof, and the conductive layer is provided on the sinker surface, and the longitudinal direction thereof is the wale direction of the knit. Or the conductive layer is provided on the needle surface, and the longitudinal direction thereof is the course direction of the knit, and therefore has a conductive layer having a conductive layer that is difficult to break even when stretched on a 2-way tricot. It can be knit.

  A strain sensor having any one of the above-mentioned knits with a conductive layer and causing a change in resistance value due to expansion and contraction of the conductive layer can be obtained. Since the strain sensor includes any one of the knits with the conductive layer and causes a change in resistance value due to the expansion and contraction of the conductive layer, it can be used as a sensor for measuring the extension of the knit.

  It can be set as the wearable sensor which has the said distortion sensor. Since it was set as the wearable sensor which has the said strain sensor, it can utilize as a sensor which forms clothing by knit and measures a body movement.

  The knit can be a wearable sensor in which at least one of compression wear, tights, supporter, glove, and socks is formed. Since at least one of compression wear, tights, supporters, gloves, and socks is formed by the knit, it is possible to provide a wearable sensor that captures the movement of a body part covered with these clothes.

  According to the knit with a conductive layer, the strain sensor, and the wearable sensor of the present invention, the knit has a comfortable wearing feeling, and the conductive layer can detect a change in resistance value. Further, even if the knit stretches, the conductive layer is hardly broken.

FIGS. 1A and 1B are schematic views of flat knitting, and FIG. 1B is a cross-sectional view corresponding to the Ib-Ib line of FIG. 1A. FIG. 2 is a plan equivalent view when the knitted fabric of FIG. It is a plane equivalent view when the knitted fabric of FIG. FIGS. 4A and 4B are schematic views of rubber knitting, and FIG. 4A is a plan equivalent view thereof, and FIG. 4B is a cross-sectional equivalent view taken along the line IXb-IXb of FIG. 4A. FIG. 5 is a plan equivalent view when the knitted fabric of FIG. FIG. 5 is a plane equivalent view when the knitted fabric of FIG. FIGS. 7A and 7B are schematic views of pearl knitting, and FIG. 7A is a plan equivalent view, and FIG. 7B is a cross-sectional equivalent view taken along the line VIIb-VIIb of FIG. 7A. FIG. 8 is a plan equivalent view when the knitted fabric of FIG. It is a plane equivalent view when the knitted fabric of FIG. FIG. 10A is a schematic diagram of a knit with a conductive layer, and FIG. 10A is a diagram corresponding to a plan view, and FIG. 10B is a diagram corresponding to a cross section taken along line Xb-Xb of FIG. It is another embodiment of the knit with a conductive layer, and is a cross-sectional view corresponding to FIG. It is another embodiment of the knit with a conductive layer, and is a cross-sectional view corresponding to FIG. It is further another embodiment of the knit with a conductive layer, and is a cross-sectional view corresponding to FIG.

  The knit with a conductive layer of the present invention will be described based on the embodiment. The knit with a conductive layer of the present invention is a laminate in which a conductive layer is laminated on a knit, and the knit is knitted by a twisted yarn twisted by a plurality of single yarns, and the conductive layer is stretchable. Further, the resistance value is changed by stretching, and the longitudinal direction of the conductive layer is formed along the direction in which the surface layer portion of the knit continues.

<Knit>
In general, the fabric is classified into a woven fabric and a knit (knitted fabric). Of these, woven fabrics made by crossing warp and weft yarns are less stretchable in the direction of the yarn, except when stretchable yarns are used, but they are more elastic and less elastic than knits. Because it is difficult to pull and is strong, it is used in many textile products such as clothing such as jackets and trousers, and household items such as rugs.

  On the other hand, the knit is formed of a continuous fabric (knitted fabric) made of loops (knitted stitches) made of fibers and entangled between the loops. In the entangled portions of the loops, in addition to the fibers being able to move relatively freely, the fabric can be stretched greatly due to the three-dimensional configuration formed by the stitches. For this reason, knits are more extensible than woven fabrics, and have features such as a soft and soft texture, heat retention and high breathability due to the three-dimensional stitches. Therefore, it is suitably used for cold protection equipment, underwear, socks that require a feeling of fit, and exercise clothes that make use of flexibility.

  Knit can be classified into flat knitting and vertical knitting. The flat knitting is the one in which the loop advances in the horizontal direction to create a knitted fabric, and the vertical knitting is the knitting of the loop in the vertical direction. In the knit, a row of loops arranged in the vertical direction of the fabric is called “wel”, and a row of loops arranged in the horizontal direction is called “course”, and the number of loops in 1 inch is expressed by a gauge. In other words, the gauge number in the wale direction is the number of yarns in the course direction per inch, and the gauge number in the course direction can be the number of loops per inch. For example, when there is a pattern shown in FIG. 1A described later on 1 inch square, the wale direction is 4 gauge and the course direction is 3 gauge. This gauge number can be measured by visual observation or observation with an optical microscope.

  Since various three-dimensional cross stitches are formed on the knit by various knitting methods, some typical examples of the knitted fabric will be described.

Flat knitting:
FIG. 1 shows a schematic diagram of a flat knitting 1 which is a typical stitch of a knit. FIG. 1A is a plan view thereof, and FIG. 1B is a sectional view thereof. In FIG. 1, for convenience, four fibers extending in the lateral direction are shown to be repeated for three loops. In practice, however, such a pattern is repeated vertically and horizontally to form a knitted fabric. ing. In FIG. 1 (a), the fiber direction in the lateral direction (X direction in FIG. 1 (a)) is the course direction in which the loops are intertwined, and the direction perpendicular to the course direction (in FIG. 1 (a)). Y direction) becomes the wale direction.

  2 and 3 are schematic views showing a state in which the fibers of the flat knitting 1 are stretched. FIG. 2 shows a state when FIG. 1A is an initial state, and FIG. 2 shows a state when extended in the course direction, and FIG. 3 shows a state when extended in the course direction. As shown in FIGS. 2 and 3, in the flat knitting 1, the extension in the course direction is larger than the wale direction. The back surface of the flat knitting 1 has a shape different from the front surface.

Rubber knitting:
FIG. 4 shows a schematic diagram of the rubber knitting 2. 4A is a plan view thereof, and FIG. 4B is a sectional view thereof. The rubber knitting 2 is a stitch characterized by a large stretchability in the course direction. 5 and 6 are schematic views showing a state in which the fibers of the rubber knitting 2 are stretched. FIG. 5A shows the state when FIG. 4A is an initial state, and FIG. 6 shows the state when it is extended in the course direction. As shown in FIGS. 5 and 6, the rubber knitting 2 is larger in the course direction than in the wale direction as in the flat knitting, but is larger in the course direction than the flat knitting 1. In the course direction change from FIG. 4 to FIG. 6, the stretch of the whole fabric is 130% (1.3 times the initial length in the lateral direction), and the gap T1 shown in FIG. The change to the gap T2 shown is as much as 250% when T1 is 100%. On the other hand, as shown in FIG. 5, the stretch in the wale direction stretches the entire fabric substantially uniformly. At this time, the dimension in the course direction tends to be small. In the rubber knitting 2, the same pattern is formed on both sides.

Pearl knitting:
FIG. 7 shows a schematic diagram of the pearl knitting 3. FIG. 7A is a plan view thereof, and FIG. 7B is a sectional view thereof. The pearl knitting 3 has a feature that the stretchability in the wale direction is large. 8 and 9 are schematic views showing a state in which the fibers of the pearl knitting 3 are stretched. FIG. 7A shows the state when FIG. 7A is an initial state, and FIG. 8 shows the state when extended in the course direction, and FIG. 9 shows the state when extended in the course direction. As shown in FIGS. 8 and 9, the pearl knitting 3 is different from the flat knitting 1 and the rubber knitting 2 in that the stretching in the wale direction is larger than the course direction. In the pearl knitting 3, the same pattern is formed on both sides.

2-way tricot:
Although the two-way tricot is not illustrated, one of the front and back surfaces is referred to as a sinker surface and the other surface is referred to as a needle surface, and either surface can be used as a surface as required.

Smooth knitting:
Smooth knitting is a variation of rubber knitting. Although smooth knitting is not shown, the knitting method is a fabric in which the back surfaces of two rubber knittings are combined, and both sides of the fabric are knitted with substantially the same stitch as the surface of the rubber knitting. Therefore, both front and back sides appear in the same way. If this cloth is used, a conductive layer in the wale direction can be formed on both sides of the cloth. For example, if this cloth having a predetermined thickness is used and conductive layers in the wale direction are formed on both sides of the cloth, the difference in the degree of curvature can be detected by the difference in the elongation of the conductive layers on the front and back of the cloth.

  In addition to these knitted fabrics, there are various other knitted fabrics such as Denby knitting, Bandai knitting, and cord knitting, and some include various changed structures.

  Next, the surface shape appearing on the knit will be described. The knit is formed by loops (knitting) of fibers (twisted yarns), and a laminated structure is formed by fibers that appear on the front surface and fibers that are hidden on the back surface at the overlapping portion of the fibers. For example, in the flat knitting 1 shown in FIGS. 1 to 3, when the left side of FIG. 1B is the front of the knitted fabric, the front side has two layers, the first layer 1a and the back side the second layer 1b. Also, the rubber braid 2 shown in FIGS. 4 to 6 has three layers of a front side first layer 2a and an intermediate second layer 2b and a back side third layer 2c shown in FIG. 4B. The pearl knitting 3 shown in FIG. 7 to FIG. 9 has three layers of a front side first layer 3a and an intermediate second layer 3b and a back side third layer 3c shown in FIG. 7B. Among these, the portion composed of the first layers 1a, 2a, 3a on the front side is referred to as a surface layer portion F, and is the second layer or lower 1b, 2b, 2c, 3b, 3c located on the back side with respect to the surface layer portion F. The part to be configured will be referred to as an inner layer part I. Further, a unique pattern is formed for each knitted fabric by such a laminated structure of the surface layer portion F and the inner layer portion I. When attention is paid to the surface layer portion F, even if the knitted fabric is stretched in any direction, this surface layer portion is formed. A portion where F continues exists, and the direction in which the surface layer portion F continues is referred to as a continuous direction of the surface layer portion F.

  As shown in FIG. 1, in the flat knitting 1, the surface layer portion F appears on almost the entire surface when the knitted fabric is not stretched, and the surface layer portion F is continuous in any of the upper, lower, left and right directions. As shown by, when the dough is stretched in the course direction, the inner layer portion I appears between the surface layer portions F. For this reason, even if the surface layer portion F is continuous in the vertical direction, the surface layer portion F is not continuous in the course direction. In other words, in the state shown in FIG. 3, the surface layer portion F that appears on the surface and is continuous in the vertical direction is formed in the “no” shape and the reverse “no” shape, and the surface layer portion F is formed on the left and right sides thereof. The inner layer portion I is divided. Even in a state where the knitted fabric is stretched in the wale direction shown in FIG. 2, the surface layer portion F continues in the vertical direction. Due to the properties of the flat knitting 1, in the flat knitting 1, the wale direction which is the vertical direction in FIG. 1 (a) coincides with the continuous direction of the surface layer portion F.

  On the other hand, as shown in FIGS. 4 to 6, the rubber knitting 2 also has a surface layer portion F in which a “B” -shaped pattern appearing on the front side of the fiber continues in the vertical direction, and an inverted “B” -shaped pattern in the vertical direction Are formed repeatedly in the left-right direction, but one set of surface layer portions F and another set of surface layer portions adjacent thereto are formed. An inner layer portion I is exposed between F and a portion that becomes a valley is formed. For this reason, the rubber knitting 2 forms a surface irregularity pattern in which raised portions and recessed portions appear alternately in the course direction regardless of whether the knitted fabric is stretched or not stretched. In the rubber knitting 2, the wale direction in FIG. 4A is the continuous direction of the surface layer portion F.

  In the pearl knitting 3, as shown in FIG. 7A, a surface layer portion F in which a “W” -shaped pattern and a reverse “W” -shaped pattern continue in the left-right direction is formed on the front side of the fiber. The inner layer portion I is exposed between F and another surface layer portion F adjacent thereto, and a portion that becomes a valley is formed. Therefore, the pearl knitting 3 is the same as the rubber knitting 2 in that the raised surface and the recessed portion appear alternately, and the rubber knitting in that the surface layer portion F and the inner layer portion I that becomes the valley appear alternately in the wale direction. Different from 2. In the pearl knitting 3, the course direction of FIG.

  As for the type of knit, any knitted fabric may be used in the presence of various knitted fabrics as described above, but there is a suitable size for the size of the stitches. When a conductive layer described later is formed of a conductive paste, it is preferable to use a knit having a relatively fine stitch called a so-called high gauge of 10 gauge or more. This is because the following problems may occur when a knit having a coarser mesh than 10 gauge is used.

  First, when the fibers are thick, the knit surface has too much unevenness, which may make printing difficult. In addition, since the repeating unit of the stitches becomes large, there is a possibility that the non-uniformity of elongation in stretching becomes large. Secondly, when the fibers are thin, the gap between the fibers becomes large, so that the conductive paste can easily penetrate and it is difficult to form a non-penetrating part. In addition, the conductive paste may penetrate the thickness of the knit and soil the surface plate of the printing press, which may make continuous printing difficult. On the other hand, if a predetermined conductive paste is printed on a 10-gauge or larger knit, it is possible to form a conductive layer that hardly causes the above-described problems and hardly breaks even when stretched.

  The type of fiber used for the knit is not particularly limited, and general natural fibers and synthetic fibers can be used. In addition, inorganic fibers such as glass fibers can be used, but they have insulating properties and are supple. Cotton, wool, rayon, nylon fiber, polyester fiber, polyurethane fiber, acrylic fiber, and the like having the same are preferable. However, it is necessary to be formed of twisted yarns twisted with a plurality of single yarns. This is because, when formed with a single yarn, the liquid coating material that becomes the conductive layer is insufficiently soaked, and adhesion with the fiber cannot be maintained when the fiber is stretched. The diameter of the twisted yarn is preferably about 0.01 to 1.0 mm. This is because if the thickness is larger than 1.0 mm, the voids of the stitches that are formed become too large and it is difficult to form the conductive layer, and if it is smaller than 0.01 mm, there is no problem in forming the knit with the conductive layer. This is because the gaps of the stitches become too small, making it difficult to obtain the characteristics as a knit, and it is difficult to use the knit for applications.

<Conductive layer>
The conductive layer is a conductive part formed on the surface of the knit. The longitudinal direction of the conductive layer is formed in a direction along the continuous direction of the surface layer portion of the knit. Such a conductive layer mainly comprises a conductive filler that develops conductivity and a polymer matrix that holds the conductive filler, and is a liquid conductive material in which a conductive material is dispersed in a binder resin having extensibility. The composition can be formed by applying the composition on a knit.

  FIG. 10 shows a schematic diagram in which a conductive layer is provided on a knit. FIG. 10A is a plan view, and FIG. 10B is a cross-sectional view. In the knit 10 with the conductive layer, five sets of the conductive layers 13 are provided on the surface 12a of the knit 12 so that the longitudinal direction of the conductive layer 13 extends in the X direction, which is the direction in which the surface layer portion F of the knit 12 continues. is there.

  The material for forming the conductive layer will be described. As the matrix having extensibility, a crosslinked rubber or a thermoplastic elastomer can be used. For example, silicone rubber, natural rubber, isoprene rubber, butadiene rubber, acrylonitrile butadiene rubber, 1,2-polybutadiene, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene-propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber , Crosslinked rubber such as epichlorohydrin rubber, fluorine rubber, urethane rubber, styrene thermoplastic elastomer, olefin thermoplastic elastomer, ester thermoplastic elastomer, urethane thermoplastic elastomer, amide thermoplastic elastomer, vinyl chloride Examples include thermoplastic elastomers such as thermoplastic elastomers and fluorine-based thermoplastic elastomers. Among these materials, silicone rubber can form an extremely flexible conductive layer and has a relatively high weather resistance, and thus is suitable for use as a wearable sensor.

  The hardness of the matrix is preferably in the range of 5 to 80 in terms of A hardness specified by JIS K6253. If it is less than A5, since it is too flexible, a concern arises in terms of durability. On the other hand, if it exceeds A80, it is too hard to stretch almost and is not suitable for the purpose of stretching. In recent years, since a human-friendly tactile sensation is required, it is more preferable to use a flexible material even within this preferable range.

  As the conductive filler, conductive powder such as carbon or metal can be used. However, in the case of wiring for transmitting electric power or signals, it is preferable to use low-resistance metal powder. Among metal powders, silver powder having a certain degree of weather resistance and an extremely low resistance value is particularly suitable. The shape of the conductive filler is not particularly limited, but the fibrous filler can have a low resistance with a relatively small filling amount. In addition, the conductive filler of the flaky powder can have a low resistance with a relatively small filling amount, and the resistivity change when expanded or contracted is small.

  Such a conductive filler is preferably blended so as to occupy 15 to 50% by volume in the conductive layer. If the amount is less than 15% by volume, the resistance value may be too high. If the amount exceeds 50% by volume, the ratio of the matrix holding the conductive filler is too small, and the conductive layer is cracked when stretched. The risk of disconnection increases.

  On the other hand, when it is desired to form a conductive layer having a large resistance change due to expansion and contraction, it is preferable to use carbon powder. As an example of the conductive layer having a large resistance change due to expansion and contraction, 3.8 to 15 parts by mass of Ketjen Black (3.6 to 23% by volume in the conductive layer) and 100% of graphite with respect to 100 parts by mass of silicone. A conductive layer made of a conductive resin containing ˜45 parts by mass (0 to 48 volume% in the conductive layer) is a preferred embodiment. If the amount of ketjen black added is less than 3.8 parts by mass, it is difficult to obtain desired conductivity and durability. On the other hand, when the amount exceeds 15 parts by mass, the viscosity of the composition mixed with silicone increases, and cracks are likely to occur when the conductive layer is stretched. On the other hand, if the amount of graphite added is less than 30 parts by mass, it is difficult to obtain an appropriate rate of change in resistance accompanying the elongation of the conductive layer. On the other hand, when it exceeds 45 parts by mass, the viscosity of the mixed composition with silicone becomes high, and the durability against stretching of the conductive layer is deteriorated.

  The conductive layer is preferably printed and formed using a liquid conductive paste. For this conductive paste, a liquid composition containing a binder and a conductive filler as the matrix can be used. Specific examples of the liquid composition include the above-mentioned conductive powder, a combination of alkenyl group-containing polyorganosiloxane and hydrogenorganopolysiloxane, which is a curable liquid resin, a combination of polyurethane polyol and isocyanate, and various rubbers. Or an elastomer dissolved in a solvent. The conductive paste can contain a solvent. By using a solvent, it is possible to adjust the dispersibility of graphite and ketjen black, the coating property on the substrate surface, and the viscosity.

  When the conductive layer is formed by printing with a conductive paste, it is preferable to include at least one conductive powder among fine particle conductive powder, fibrous conductive powder, and scaly conductive powder. The reason for this is that by including any one of these, the thixo ratio of a predetermined conductive paste can be adjusted to 3 to 30, and a conductive layer having a predetermined resistance value range can be obtained after solidification. It is. In particular, by setting the thixo ratio within this range, it is possible to suppress the conductive paste from penetrating into the knit more than necessary, so that high-quality patterning is possible.

The viscosity in the present invention indicates the viscosity at 25 ° C. measured at a rotational speed of 10 rpm using a rotor of spindle SC4-14 with a viscometer (BROOKFIELD rotational viscometer DV-E) unless otherwise described. To do. Furthermore, the thixotropic index is a measure _{mu 10rpm} in the rotation speed 10rpm viscometer, a ratio of the measured value _{mu 100 rpm} in rotational speed _{100rpm (μ 10rpm / μ 100rpm)} .

  The conductive paste or the conductive layer can contain various additives for the purpose of enhancing various properties such as productivity, weather resistance, and heat resistance. Examples of such additives include various functional improvers such as a plasticizer, a reinforcing material, a colorant, a heat resistance improver, a flame retardant, a catalyst, a curing retarder, and a deterioration inhibitor.

<Penetration of conductive layer into knit>
The conductive layer is laminated on the surface of the knit by partly immersing the conductive layer in the knit. When the conductive layer does not soak into the knit and the conductive layer and the knit adhere to each other, the adhesion of the conductive layer to the knit is inferior, and the conductive layer easily peels off or the conductive layer It is because it is easy to be cut. However, the penetration of the conductive layer into the knit has the advantage of improving the adhesion of the conductive layer to the knit, whereas the conductive layer soaked in the knit is a contact between the conductive materials in the conductive layer. May be hindered by the knit fiber and increase the resistance value of the conductive layer.

  As shown in FIG. 10B, when the conductive layer 13 is distinguished into a penetration portion 13a that is a portion soaked in the knit 12, and a non-penetration portion 13b that is a portion on the surface of the knit 12, The thickness of the infiltration portion 13b is preferably 50 to 1000 μm. If it is less than 50 μm, cracks may easily occur in the conductive layer 13 depending on the type of the knit 12. On the other hand, when the thickness exceeds 1000 μm, even when a flexible material is used for the conductive layer 13, the expansion and contraction stress becomes large, and the wearing feeling may be impaired. On the other hand, it is preferable that the penetration portion 13a penetrates the twisted yarn of the surface layer portion F at a depth of 10 to 50% of the thickness of the twisted yarn. If it is less than 10%, the conductive layer 13 may be easily cut or peeled off. On the other hand, if it exceeds 50%, the reinforcing effect against the disconnection of the conductive layer 13 is already sufficient, but the soft texture of the knit 12 is impaired, and the knit 12 is restrained and its expansion and contraction hardly occurs.

  The width of the conductive layer can be formed to an appropriate size as necessary, but is preferably 0.1 mm or more. If the thickness is less than 0.1 mm, the width of the conductive layer is too thin and it is difficult to obtain desired conductivity, and the possibility of breakage increases. The upper limit of the width of the conductive layer is not limited.

  The conductive layer is not limited to being provided only on the front surface of the knit, but may be provided on the back surface together with the front surface of the knit. For fabrics with different surface layer continuous directions on the front and back surfaces, by forming a conductive layer in the direction along the continuous direction of the surface layer on each surface, displacement in a plane that is not limited to a single direction It can be set as the sensor which detects this. In flat knitting, a conductive layer is formed along the wale direction (longitudinal direction) that is the continuous direction of the surface layer portion on one side of the fabric, and the course direction (lateral direction) that is the continuous direction of the surface layer portion on the other side of the fabric. ) Can be formed along. In this way, by configuring the conductive layers that intersect perpendicularly when viewed in plan on both the front and back sides of the fabric, it is possible to detect the direction of elongation from the ratio of the resistance value change of the conductive layers provided on the front and back surfaces. .

  Various functional layers can be laminated on the surface of the knit with a conductive layer as necessary. For example, in the knit 20 with a conductive layer shown in FIG. 11, a protective layer 14 that covers the surface of the conductive layer 13 and the surrounding knit 12 can be provided on the surface of the knit 12 on the side where the conductive layer 13 is provided. The protective layer 14 is preferably formed of a transparent and flexible resin material, and can protect the surface of the conductive layer 13 and more securely fix the conductive layer 13 to the knit 12.

  Moreover, as shown in FIG. 12 and FIG. 13, the adhesive layer 15 can be provided on at least one of the front and back surfaces of the knit 30 with conductive layer. In the knit 30a with a conductive layer shown in FIG. 12, the adhesive layer 15a is formed on the surface on the side where the conductive layer 13 is provided. The adhesive layer 15a can also serve as the protective layer 14, and the conductive layer 13 can be made invisible from the surface of the knit 12 by using the adhesive layer 15a so as to adhere to the skin. Therefore, the conductive knit 30a can be used without impairing the decorativeness of the knit 12. In addition, since the body and the conductive layer 13 are brought into close contact with each other through the adhesive layer 15a, it is possible to reduce the deviation of the extension of the body surface and the extension of the conductive layer due to the bending of the body and enable accurate sensing. Can do. In addition, permeation of sweat can be suppressed by the adhesive layer 15a. Therefore, compared with the case where the adhesive layer 15a is not provided, a change in the amount of moisture in the vicinity of the conductive layer 15a can be reduced, and a change in sensor sensitivity due to sweat can be reduced.

  In the knit 30b with conductive layer shown in FIG. 13, the adhesive layer 15b is formed on the surface opposite to the side on which the conductive layer 13 is provided. By using the adhesive layer 15b side so as to adhere to the skin, the conductive layer 13 can be taken out of the knit 12 when viewed from the body, and the conductive portion 13 can be made less susceptible to the effects of sweat generated from humans. . Further, it is possible to prevent the conductive layer 13 from being deteriorated due to rubbing with the body, and further to prevent noise from being mixed due to contact with the body, and to easily detect a more accurate change in resistance value.

  The adhesive layer 15 can be made of the same material as that used for adhesive bandages and ships, and acrylic adhesives, polymer gels, and the like can be used. By providing the adhesive layer 15 in this way, the knit 30 with a conductive layer can be attached to the skin and can be suitably used for the purpose of improving the adhesion to the body.

<Method for producing knit with conductive layer>
To manufacture a knit with a conductive layer, prepare the knit and print a raw material composition such as a conductive paste that becomes a conductive layer on the knit so that the continuous direction of the surface layer and the longitudinal direction of the conductive layer coincide. Apply by the method. Then, the applied raw material composition is cured. When providing functional layers such as a protective layer and an adhesive layer, a knit with a conductive layer can be obtained by further applying and curing a raw material composition serving as these functional layers on the desired knit surface.

<Use of knit with conductive layer>
Clothing that adheres to the body, such as compression wear, tights, and supporters:
The knit with the conductive layer can be used as a part of clothing such as compression wear, tights, and supporters that are in close contact with the body. In addition to daily use, such garments are used to enhance joint support and performance, particularly in the field of sports. This type of clothing includes some that limit the movement of the body by keeping the elasticity in a specific direction within a predetermined range, and some that have excellent elasticity and do not hinder the movement of the body, but both are closely attached to the human body An elastic fabric is used. And it wears in the state which always adhered to the body by expanding and contracting following the movement of the body surface.

  In such a garment, a conductive layer is disposed at a location corresponding to the movement of a human joint or muscle. More specifically, taking an elbow joint or a knee joint as an example, a conductive layer is disposed along the length direction of the limbs on the surface on the side where these joints are extended. By forming such a conductive layer, it is possible to configure a wearable sensor whose resistance value changes with the movement of the joint.

  As a preferred embodiment in this case, the garment is sewn so that the direction in which the surface layer portion of the knit is continuous in the length direction of the limbs (the direction in which expansion and contraction is large), and the surface layer portion of the knit is substantially parallel to the continuous direction. A conductive layer is formed as a sensor electrode. For example, taking smooth knitting as an example, the knit wale direction is set as the longitudinal direction of the arms and legs, and the course direction is set as the circumferential direction of the arms and legs. Then, a wearable sensor whose resistance value changes due to expansion and contraction corresponding to the movement of the joint is formed by forming a conductive layer as a sensor electrode substantially parallel to the waling direction of the knit on the portion outside the joint of the knit. can do.

  Using such wearable sensors configured as clothing that is in close contact with the body, such as compression wear, tights, and supporters, it is possible to monitor the movement of the body during sports, for example. On the contrary, it is also possible to use for the prevention of economy class syndrome by monitoring the movement of the joint and notifying when there is no movement for a predetermined time.

Gloves and socks:
A knit with a conductive layer can be used for gloves and socks. In this case, a conductive layer is formed as a sensor electrode that detects movement of the wrist, ankle, or joint of the hand or foot. Specifically, the conductive layer is formed so that the length direction of the limb and the length direction of the conductive layer coincide with each other on the wrist, the ankle, and the finger. As a preferred embodiment, a glove or a sock that is sewn so that the longitudinal direction of the limbs is the direction in which the surface layer portion of the knit is continuous, and the surface layer portion of the knit is continuous in the portion that is outside the joints. By forming a conductive layer substantially in parallel with the conductive layer, it is possible to configure a wearable sensor in which the conductive layer expands and contracts following the movement of the joint and the resistance value changes.

  This wearable sensor can be used as an input interface of a VR system or a game machine, for example, by detecting the movement of a joint of a hand or a foot. In addition, it is useful as a sensor for monitoring body movements during sports, in combination with clothing such as compression wear, tights, and supporters that are in close contact with the body.

  When using as a knit wearable sensor with a conductive layer, it is possible to connect wiring to both ends of the conductive layer and connect the wiring to the control module. The control module has a battery, a wireless communication unit, and a control unit, detects a change in resistance value that changes due to expansion and contraction of the conductive layer, and transmits the signal to a wearable operation terminal such as a wearable watch or a personal computer separately provided. is there. A compact control module and wiring can be assembled to the knit.

<Preparation of sample>
The test pieces of the knit with conductive layers of Samples 1 to 5 described below were produced, and the resistance value change when this was stretched and the stretch rate when the conductive layer was broken were measured. As described in Table 1, each sample is obtained by changing the kind of fabric and the direction in which the conductive layer is formed.

  The fabric (knit 1) used for Sample 1 is a smooth knitted fabric made of twisted polyester fibers and having a gauge of 30 gauge in the wale direction and 30 gauge in the course direction. The fabric (knit 2) used for the sample 2 is a fabric of rubber knitting (twisted rubber knitting) having a 20-gael direction and a 20-gauge direction in the course direction. The fabric (knit 3) used for Sample 3 and Sample 4 is a 2-way tricot fabric made of twisted fibers of 85% nylon and 15% polyurethane and having a gauge of 40 gauge in the wale direction and 70 gauge in the course direction. The sample 5 is a silicone rubber sheet having a thickness of 1 mm as an example other than the cloth.

  About the cloth | dough of the samples 1-4, what made the magnitude | size of the wale direction 70mm x course direction 20mm (samples 1a-4a) and what made the wale direction 20mm x course direction 70mm (samples 1b-4b) were prepared. About the silicone rubber sheet of the sample 5, what prepared the magnitude | size of 70 mm x 20 mm was prepared.

  The conductive paste to be the conductive layer is a mixture of 15 parts by mass of ketjen black (particle size 40 nm) with 100 parts by mass of addition reaction type liquid silicone (viscosity 100 Pa · s, hardness A25 after hardness), 25 A material having a viscosity of 100 Pa · s at 10 ° C. (rotational speed of 10 rpm) and a thixo ratio of 29 was prepared.

  The conductive layer is formed on the test piece of each sample by fixing the cloth of each sample on the printing table and forming a sensor pattern having a width of 1.0 mm and a length of 25 mm in the center of the cloth. The conductive paste was screen printed using a metal mask and heated at 120 ° C. for 30 minutes.

<Elongation of each sample and measurement of resistance value>
After both ends of the conductive layer are connected to a digital multimeter (Yokogawa Meter & Instruments 73201), both ends in the longitudinal direction of each test piece are fixed to a jig, and one end is pulled while being pulled in the longitudinal direction by a load cell. The resistance value in each stretched state shown in 1 was read.

  In Table 1, the initial resistance value of each test piece (resistance value measured without stretching each test piece) is shown in the “Initial” column. The resistance value when the initial length of the conductive layer 25 mm is increased by 1.2 times to 30 mm and the resistance value is increased by 1.5 times to 37.5 mm in the column “120%”. The resistance value when the value is doubled to 500 mm in the column “150%” is shown in the column “200%”. At this time, when the resistance value of the conductive layer exceeded the measurement limit of the digital multimeter, it was indicated as “disconnected”. However, the breakage of the conductive layer at the same time as the breakage of the fabric (broken or broken) was indicated as “material breakage”.

  Separately from the measurement of the resistance value at the predetermined stretch rate, the limit of the stretch length of the conductive layer was evaluated. This is the expansion ratio of the conductive layer when the resistance value exceeds 40 MΩ which is the measurement limit of the digital multimeter (percentage of the length of the conductive layer when the measurement limit is exceeded with respect to the initial length of 100% of the conductive layer). It was described in Table 1 as “Length at disconnection (%)”. However, when the measurement limit is exceeded, if the disconnection of the conductive layer coincides with the breakage of the fabric, it is supplemented with “material breakage”. The reason for distinguishing “material breakage” of the fabric is that the present invention is characterized by enhancing the extensibility of the conductive layer. If the limit of the fabric is small, the limit of the extensibility of the conductive layer cannot be evaluated. is there. In addition, conditions not examined are indicated by “-” in Table 1.

  For example, when the knit 1 (sample 1a) having a size of 70 mm in the wale direction × 20 mm in the course direction is stretched 1.2 times in the wale direction to 30 mm, the resistance value in Table 1 is “resistance value (kΩ ) ”,“ Wale direction ”and“ 120% ”, and it can be seen that it is 16.7 kΩ. Further, when the knit 2 (sample 2b) having a size of 70 mm in the course direction × 20 mm in the wale direction is stretched in the course direction and the resistance value exceeds the measurement limit of the digital multimeter, the stretch ratio of the conductive layer is “ It is shown in the column of “length at disconnection (%)” and “course direction”, and it can be seen that it is 160%, that is, when the conductive layer extends to 40 mm.

<Evaluation of each sample>
About Knit 1:
The resistance value of the sample 1a in which the conductive layer is provided in the wal direction with the knit 1 by smooth knitting is similar to the resistance value of the sample 5 in which the conductive layer is provided on the silicone rubber sheet, which is a preferable characteristic. Further, the knit was torn off when the conductive layer was stretched by 240%, but no cracks were generated other than at the torn portion, and the conductive layer appeared to be stretched further. On the other hand, in the sample 1b in which the conductive layer was provided in the course direction with the same knit 1, the measurement limit of the digital multimeter was exceeded when the conductive layer was extended 160%. Therefore, it was found that the conductive layer can be stretched more when the conductive layer is formed in the wale direction which is the continuous direction of the surface layer portion.

About Knit 2:
The resistance value of the sample 2a in which the conductive layer is provided in the wale direction with the knit 2 made of rubber knitting was comparable to that of the sample 5 in which the conductive layer was provided on the silicone rubber sheet up to 150%. When it reached 200%, the knit was broken. In addition, the resistance value of the sample 2b in which the conductive layer is provided in the course direction with the same knit 2 is slightly larger than the resistance value of the sample 2a in which the conductive layer is provided in the wale direction. I was disconnected. Therefore, it was found that the conductive layer can be stretched more when the conductive layer is formed in the wale direction which is the continuous direction of the surface layer portion.

About Knit 3:
In Sample 3a in which the conductive layer was provided in the wale direction of the 2-way tricot knitted sinker surface, the conductive layer was disconnected when the conductive layer had an elongation of 200%. On the other hand, the sample 3b provided with the conductive layer in the course direction was disconnected at 100%, and it was found that cracks were less likely to occur when the conductive layer was formed in the wale direction, which is the direction in which the surface layer portion is continuous.

  Further, in the sample 3b in which the conductive layer was provided in the course direction of the two-way tricot knitted sinker surface, it was disconnected from the initial state, but when the state of the conductive layer was observed, a slight crack was generated. The reason why such cracks occur is that, since the fiber is nylon, in addition to the poor wettability of the conductive paste, the gap between the continuous surface layer portion and other surface layer portions is wide, so the conductive paste adheres to that portion. It seems that it was caused by the difficulty.

  Both the sample 4a in which the conductive layer was provided in the wale direction of the needle surface of the 2-way tricot knitting and the sample 4b in which the conductive layer was also provided in the course direction of the needle surface were capable of stretching 200% or more. Also, the resistance value was similar. When these extend beyond 200%, in the sample 4a in which the conductive layer is provided in the wale direction, the conductive layer is disconnected when the expansion rate is 240%, and in the sample 4b in which the conductive layer is provided in the course direction, the extension rate is obtained. When the value reached 340%, the conductive layer was disconnected. Therefore, it was found that the sample 4 also had higher tolerance for stretching of the conductive layer when the conductive layer was formed in the continuous direction of the surface layer portion (course direction).

About rubber sheet:
In Sample 5, the silicone rubber sheet broke when the elongation rate of the conductive layer was 400%, but no cracks were observed in the conductive layer until then. Therefore, the conductive layer itself has a property that does not break even at an elongation rate of at least 400%.

DESCRIPTION OF SYMBOLS 1 Flat knitting 1a 1st layer 1b 2nd layer 2 Rubber knitting 2a 1st layer 2b 2nd layer 2c 3rd layer 3 Pearl knitting 3a 1st layer 3b 2nd layer 3c 3rd layer 10, 20, 30, 30a, 30b Knit with conductive layer 12 Knit 12a Surface 13 Conductive layer 13a Penetration portion 13b Non-penetration portion 14 Protective layer 15, 15a, 15b Adhesive layer F Surface layer portion I Inner layer portion

Claims (9)

A knit with a conductive layer in which a conductive layer is laminated on a knit,
The knit is knitted with a twisted yarn twisted with a plurality of single yarns,
The conductive layer is stretchable and causes a change in resistance value by stretching,
A knit with a conductive layer in which the longitudinal direction of the conductive layer is formed along the direction in which the surface layer portion of the knit continues.
2. The knit with a conductive layer according to claim 1, wherein the conductive layer penetrates at a depth of 10 to 50% of the thickness of the twisted yarn on the twisted yarn of the surface layer portion of the knit.
The knit with a conductive layer according to claim 1 or 2, wherein the conductive layer is a cured body of a conductive paste in which a conductive powder is dispersed in a crosslinked rubber or a thermoplastic elastomer.
The knit is at least one knit selected from flat knitting, rubber knitting, or any one or a combination thereof, and the longitudinal direction of the conductive layer is the wale direction of the knit. Item 4. The knit with a conductive layer according to any one of Items 3.
The knitted fabric is at least one knitted selected from pearl knitting or any one or a combination thereof, and the longitudinal direction of the conductive layer is the course direction of the knit. Item 1. A knit with a conductive layer according to item 1.
The knit is at least one knit selected from a 2-way tricot or any one or a combination thereof, and the conductive layer is provided on a sinker surface, the longitudinal direction of which is the wale direction of the knit The knit with a conductive layer according to any one of claims 1 to 3, wherein the conductive layer is provided on a needle surface, and a longitudinal direction thereof is a course direction of the knit.
A strain sensor comprising the knit with a conductive layer according to any one of claims 1 to 6 and causing a change in resistance value due to expansion and contraction of the conductive layer.
A wearable sensor comprising the strain sensor according to claim 7.
The wearable sensor according to claim 8, wherein the knit forms at least one of compression wear, tights, supporter, glove, and socks.

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