A method for continuously producing conductive threads.

Abstract

The present invention provides a method for continuously producing conductive yarn, which enables the imparting of conductivity to the yarn regardless of the fiber material, thickness, or twisting method, and maintains the conductivity of the yarn even when stress is applied to it. [Solution] An organic compound is mixed with an aggregate of fine crystals of a metal compound to create a first suspension in which the fine crystals are dispersed in the organic compound. Then, the fine crystals are thermally decomposed to create a second suspension in which metal nanoparticles of about 10 nm in size are surrounded by the organic compound. A thread is continuously drawn from a bobbin and continuously immersed in the second suspension. Furthermore, the thread is continuously wound around a spirally formed cylindrical groove, and the cylinder is moved into the chamber of a vacuum impregnation device, where the pressure inside the chamber is reduced to a pressure lower than the vapor pressure of the organic compound. As a result, a conductive thread is produced in which aggregates of metal nanoparticles are continuously bonded by friction pressure welding to the voids inside the thread and the surface irregularities and surface.

Description

[Technical Field]

[0001] The present invention relates to a method for continuously manufacturing conductive yarn in which an aggregate of metal nanoparticles is formed by friction welding, with the internal voids and surface irregularities of the yarn being continuously joined to the surface. Yarn is composed of two types of fibers: filament yarn (long fibers) and spun yarn (short fibers). Spun yarn (short fibers) is unsuitable for continuously producing conductive yarn due to its short length. Long fibers are called filaments, and the term refers to continuous, endless fibers (for example, fibers that can reach lengths of 1000m). Furthermore, filaments include monofilaments (e.g., fishing line), which are composed of a single long fiber, and multifilaments, which are made by twisting multiple long fibers together. The tensile strength of a multifilament is close to the tensile strength of a monofilament multiplied by the number of monofilaments. Furthermore, the tensile strength of a yarn made by twisting multiple multifilaments together is close to the tensile strength of a multifilament multiplied by the number of multifilaments. In addition, multifilaments, which are made by twisting multiple monofilaments together, have more internal voids and surface irregularities than monofilaments. Furthermore, yarns made by twisting multiple multifilaments together have more internal voids and surface irregularities than monofilaments. Furthermore, the tensile strength of a yarn made by twisting multiple multifilaments together is greater than the tensile strength of a yarn made solely of multifilaments. For this reason, a yarn made by twisting multiple multifilaments together was used as the yarn to impart conductivity. In other words, the present invention continuously manufactures conductive yarn in which an aggregate of metal nanoparticles is formed by friction welding to the internal voids and surface irregularities of the yarn. For this reason, yarn made by twisting multiple multifilaments together is in line with the essence of the present invention. Furthermore, yarn made by twisting multiple multifilaments together has a tensile strength greater than that of yarn made of multifilaments alone. Furthermore, fibers are broadly classified into natural fibers and synthetic fibers based on their material. Natural fibers are further classified into plant fibers and animal fibers based on their material. Many natural fibers begin to decompose at a temperature lower than the decomposition temperature of the metal compounds that are the raw materials for metal nanoparticles. Therefore, by the time the metal nanoparticles precipitate due to the decomposition temperature of the metal compounds, the thermal decomposition of the fibers has already progressed, resulting in a decrease in the performance of the fibers. This decrease in fiber performance is irreversible. Cotton, a plant fiber, is the only exception, as its decomposition temperature is higher than the decomposition temperature of the metal compounds. However, since cotton is a spun yarn made by twisting short fibers together, it is unsuitable for continuously producing conductive yarn. Chemical fibers are classified into regenerated fibers, semi-synthetic fibers, synthetic fibers, and inorganic fibers based on differences in raw materials and manufacturing methods. Regenerated and semi-synthetic fibers have lower tensile strength than synthetic fibers, making them unsuitable for continuously producing conductive yarns. Furthermore, while polyurethane fibers are a common synthetic fiber, their tensile strength is only 1 / 4 to 1 / 5 that of other common synthetic fibers, making them unsuitable for use as conductive yarns. Furthermore, synthetic fibers that are high-performance and functional, derived from inorganic fibers such as glass fibers, para-aramid fibers, polyacrylonitrile carbon fibers, fibers made from polyethylene with extremely high molecular weight, polyarylate fibers, poly-paraphenylenebenzoxazole fibers, and high-strength polyvinyl alcohol fibers in which the hydroxyl groups of polyvinyl alcohol are hydrogen-bonded, have a tensile strength an order of magnitude greater than general-purpose synthetic fibers. However, they are more expensive than general-purpose synthetic fibers, making them suitable for applications such as conductive yarns that require high tensile strength. Therefore, the present invention uses a yarn made by twisting together multiple multifilaments. Furthermore, the multifilaments used are made of general-purpose synthetic fibers excluding polyurethane fibers, and synthetic fibers made of glass fibers and high-performance fibers. The present inventors have previously filed a patent application, Japanese Patent Application No. 2021-205624, for "a method for manufacturing fibers, yarns, fabrics, or nonwovens to which metallic properties have been imparted." This prior application describes a method for manufacturing conductive yarn by batch processing. In contrast, the present invention is a method for continuously manufacturing conductive yarn, and therefore the manufacturing method is different. [Background technology]

[0002] In recent years, sheets made of conductive fibers have been studied as electromagnetic shielding materials to block electromagnetic waves generated from electronic devices such as mobile phones, and fabrics made of conductive fibers have been studied as antistatic or anti-static materials to suppress the generation of static electricity. Furthermore, among conductive fibers, the development of technologies to impart conductivity to polymer materials is the most active. These technologies for imparting conductivity can be divided into two categories: technologies for dispersing conductive substances and technologies for forming metal films. Examples include technologies using polymer compositions mixed with conductive substances such as carbon powder and metal powder (see, for example, Patent Document 1), technologies for forming metal vapor-deposited films such as tin oxide on plastic molded products by vacuum deposition (see, for example, Patent Document 2), and technologies for forming metal films on the surface of polymer fiber materials by electroless plating (see, for example, Patent Document 3).

[0003] Furthermore, while many of the electric and transmission wires currently in use are made of metal wires such as copper, metal wires are heavy and have low tensile strength. Therefore, technological development is underway to replace them with conductive fibers that are lightweight and have excellent tensile strength. As such technologies, fibers with a metal coating have been proposed, such as aramid fibers, PBO (poly-p-phenylene benzoxazole) fibers, and polyarylate fibers, which are tensile strength fibers, by means of metal plating or by wrapping them with metal foil. In addition, electric wires in which these metal-coated fibers are used as conductors and covered with an insulator have also been proposed (see, for example, Patent Documents 4-6).

[0004] However, polymer compositions filled with conductive materials such as carbon powder or metal powder are composed of polymers with dispersed conductive particles and non-conductive polymers, which presents a problem as the conductive and non-conductive parts tend to separate easily. Furthermore, in order to obtain conductivity close to that of a metal, the packing density of conductive particles must be increased, but the higher the packing density of conductive particles, the more the polymer composition loses its properties. In other words, in techniques that disperse conductive particles in fibers or threads, unless a structure is formed in the thread that allows a continuous electric current to flow through the conductive particles, conductivity close to that of a metal cannot be achieved. On the other hand, if the packing density of conductive particles is increased in an attempt to improve conductivity, the thread loses its inherent properties. However, if the packing density is increased to more than 10%, the dispersibility of the conductive particles begins to deteriorate, and a high packing density cannot be achieved. Thus, because it is difficult to pack conductive particles at a high packing density, it is fundamentally difficult to bring the properties of fibers or threads closer to those of a metal.

[0005] On the other hand, technologies that form metal films using methods such as vacuum deposition have problems with the abrasion resistance and weather resistance of the metal film, as well as the deterioration of physical properties due to chemical changes over long-term use. Furthermore, the formation of metal films is very expensive to manufacture, which limits its practical use. In addition, technologies that form metal films using electroless plating require many processes and advanced technology, resulting in high manufacturing costs. Moreover, friction and bending applied to the fibers during use or processing can cause the metal film to peel off the fibers. In other words, the technique for forming a metal film on the surface of fibers or threads involves depositing precipitated metal foil to create the metal film. Consequently, the precipitated metal foils do not bond to each other through metallic or covalent bonds. Therefore, the bonding force between the metal foils is extremely weak, and the metal foils easily peel off when stress is applied to the metal film. Thus, the problem of the metal film easily peeling off stems from the layering of precipitated metal foils, and this problem cannot be fundamentally solved. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2000-212453 [Patent Document 2] Japanese Examined Patent Publication No. 61-132652 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2000-96431 [Patent Document 4] Japanese Unexamined Patent Application Publication No. 2011-153365 [Patent Document 5] Japanese Unexamined Patent Application Publication No. 2008-130241 [Patent Document 6] Japanese Unexamined Patent Application Publication No. 2009-242839 [Non-Patent Document]

[0007] [Non-Patent Document 1] Fiber Handbook, 3rd Edition, The Fiber Society, Maruzen Publishing Co., Ltd., PP.918-926, 2004 [Disclosure of the Invention] [Problems to be Solved by the Invention]

[0008] However, there have been no attempts to impart conductivity to yarn in general. Therefore, firstly, conductive yarn can be continuously manufactured regardless of the material of the fibers constituting the yarn, as well as the thickness and twisting method of the yarn. Secondly, the conductivity of the yarn can be maintained even if tensile or bending stress is applied to the yarn during processing. Thirdly, conductive yarn can be continuously manufactured using inexpensive materials at low manufacturing costs. Furthermore, the tensile elongation rate at which the fibers break when pulled is an order of magnitude greater than the tensile elongation rate of copper wire or hard aluminum wire. Therefore, the tensile strength of the fibers is greater than that of copper wire or hard aluminum wire of the same thickness. Consequently, if the above three requirements are met, since the yarn is made by twisting together multiple fibers, and the tensile strength of the yarn is close to the value obtained by multiplying the tensile strength of the fibers by the number of fibers, a conductive yarn can be obtained that has greater tensile strength than metal wire made of copper wire or hard aluminum wire, and is also lightweight. Fourth, the entire surface of the yarn is covered with metal. This isolates the yarn from the atmosphere, imparting non-flammability to the flammable yarn, preventing it from burning, preventing the spread of fire, and further suppressing the generation of harmful gases. Moreover, fabrics or nonwovens formed using conductive yarn not only exhibit significantly improved performance in electromagnetic shielding, static electricity, antistatic properties, and electrical conductivity, but also become lightweight conductive and non-flammable films or lightweight conductive and non-flammable sheets with excellent thermal conductivity and corrosion resistance. The problem to be solved in this invention is to find a method for continuously manufacturing conductive yarn that possesses the four requirements described above. [Means for solving the problem]

[0009] The present invention provides a method for continuously manufacturing conductive threads in which an aggregate of metal nanoparticles is formed by friction welding to the internal voids and surface irregularities of the thread, and to the surface itself. The first step involves dispersing a metal compound in methanol that possesses both the first property of being dispersed in methanol but not soluble in methanol, and the second property of precipitating metal by thermal decomposition, to create a methanol dispersion of the metal compound; then, vaporizing methanol from the methanol dispersion of the metal compound to precipitate an aggregate of crystals of the metal compound having a size of approximately 100 nm; and finally, filling the aggregate of metal compound crystals into a container. A plate material is placed over the aggregate of metal compound crystals in the container, covering the entire surface of the aggregate. After this, a compressive load is applied to the entire surface of the plate material to pulverize the metal compound crystals in the container. Furthermore, impact acceleration in three directions (front / back, left / right, and up / down) is repeatedly applied to the sides and bottom of the container to rearrange the pulverized aggregate of metal compound crystals within the container. After this, the compressive load is applied again to the entire surface of the plate material to further pulverize the metal compound crystals. Furthermore, the impact acceleration in the three directions is repeatedly applied again to the sides and bottom of the container. This pair of processes, consisting of applying the compressive load and applying the impact acceleration, is repeated. When the plate material stops moving when the compressive load is applied, it is determined that the pulverization of the metal compound crystals is complete, and the pair of processes is stopped. As a result, the metal compound crystals are pulverized into fine crystals of 1 / 5 of their original size. After this, the plate material is removed from the container. An organic compound possessing the following four properties is weighed in an amount greater than the aggregate of fine crystals of the metal compound in the container: first, the metal compound crystals do not dissolve or disperse; second, the boiling point is higher than the thermal decomposition temperature of the metal compound; third, the metal fine particles precipitated at the thermal decomposition temperature of the metal compound do not react chemically; and fourth, the viscosity at 20°C is 2-5 mPa·s. The weighed organic compound is then mixed into the container filled with the aggregate of fine crystals of the metal compound. As a result, the aggregate of fine crystals of the metal compound is made to possess the four properties of the organic compound. A first suspension is created in which the metal compound is dispersed. Further, an ultrasonic homogenizer is placed in the container, and by operating the ultrasonic homogenizer, shock waves are continuously generated in the first suspension. The shock waves continuously collide with the cluster of fine crystals of the metal compound, separating the cluster of fine crystals into individual fine crystals. Each of these separated individual fine crystals is surrounded by the organic compound, and a second suspension consisting of the cluster of individual fine crystals surrounded by the organic compound is created in the container. After this, the ultrasonic homogenizer is removed from the container in a third step. A heat treatment apparatus is prepared, comprising an atmosphere that causes the fine crystals of the metal compound to decompose. The container is placed in the heat treatment apparatus, the heat treatment apparatus is heated to a temperature at which the fine crystals of the metal compound decompose, and then maintained at this decomposition temperature for a predetermined time. As a result, metal nanoparticles approximately 10 nm in size precipitate, surrounded by the organic compound, and a third suspension consisting of a collection of these metal nanoparticles surrounded by the organic compound is created in the container. After this, the container is removed from the heat treatment apparatus in a fourth step. The thread, which consists of multiple multifilaments twisted together, is wound on a first bobbin, and the thread is continuously drawn out at a drawing speed of 0.2 cm per second. The drawn thread is then continuously immersed in a third suspension in the container, and further moved through the third suspension at a movement speed of 0.2 cm per second. After this, the thread is continuously pulled out of the third suspension at a pulling speed of 0.2 cm per second. Next, the thread has an outer diameter 20 times the outer diameter of the core of the first bobbin and a height 10 times the height of the core of the first bobbin, and the A cylinder is prepared in advance, having spiral grooves that are twice the width of the thread and five times the depth of the thread, and are provided continuously from the lower end to the upper end of the side surface at intervals twice the width of the thread. The cylinder is installed in a rotating device, the thread pulled up from the third suspension is inserted into the groove at the lower end of the side surface of the cylinder, and then the rotating device is rotated at a peripheral speed of 0.2 cm per second, winding the thread pulled up from the third suspension into the groove at the upper end of the side surface of the cylinder. After this, the cylinder is removed from the rotating device. The yarn is transferred into the chamber of a vacuum impregnation apparatus, the chamber is sealed, and the vacuum pump attached to the vacuum impregnation apparatus is operated to reduce the pressure inside the chamber to a pressure lower than the vapor pressure of the organic compound. As a result, first, the air present in the yarn is discharged to the outside of the chamber, and the aggregate of metal nanoparticles surrounded by the organic compound enters both the voids inside the yarn and the irregularities on its surface, and the surface of the yarn is covered with the aggregate of metal nanoparticles surrounded by the organic compound. Next, the organic compound vaporizes, and the vaporized organic compound The composite is discharged outside the chamber, and as a result, because the vapor pressure of the organic compound is a minute vapor pressure of less than one order of magnitude, a negative pressure close to atmospheric pressure acts on the thread, and because the metal nanoparticles, which are about 10 nm in size, have almost no mass, the aggregate of metal nanoparticles moves at a very high speed while colliding with each other, and the aggregate of metal nanoparticles sequentially fills the voids inside the thread and the surface irregularities and surface, and aggregates of metal nanoparticles that are continuously joined by frictional pressure welding are formed on the voids inside the thread and the surface irregularities and surface, in the fifth step, The sixth step involves returning the pressure inside the chamber of the vacuum impregnation apparatus to atmospheric pressure, removing the cylinder from the chamber, continuously drawing out the thread from a groove provided on the side of the cylinder, and continuously winding the drawn-out thread onto a second bobbin. A method for continuously producing conductive yarn is one in which all six processes described above are carried out in a continuous manner, and an aggregate of metal nanoparticles is formed by friction welding to the voids inside the yarn, the irregularities on its surface, and the surface itself.

[0010] The present invention provides a method for continuously manufacturing conductive yarn in which an aggregate of metal nanoparticles is formed by friction welding to the internal voids and surface irregularities of the yarn. This method involves continuously performing all six of the following processes. Each processing method and the effects it produces will be explained below. In the first step, a collection of metal compound crystals is precipitated by thermal decomposition. To achieve this, a methanol dispersion of the metal compound is prepared, and then methanol is vaporized from this dispersion, causing a collection of metal compound crystals, approximately 100 nm in size, to precipitate. In other words, when a metal compound that precipitates metal by thermal decomposition is dispersed in methanol, the most common organic solvent, the metal compound disperses in methanol in a molecular state. In contrast, when a metal compound dissolves in methanol, the metal constituting the metal compound dissolves into the methanol as metal ions, and the dissolved metal compound cannot return to its original state. Therefore, even if methanol is vaporized from a methanol solution of the metal compound, the crystals of the metal compound that were dissolved before do not precipitate. Consequently, metal compounds that precipitate metal by thermal decomposition are those that disperse in methanol without dissolving. When methanol is vaporized from a methanol dispersion of the metal compound, the metal compound precipitates as crystals of the metal compound with a size of approximately 100 nm. These crystals are an accumulation of crystals formed by single molecules of the metal compound, as the metal compound dispersed in methanol in a molecular state precipitated as crystals. Therefore, when stress is applied to the crystals, they are easily crushed into fine crystals. On the other hand, the finer the crystals become, the more difficult it is to apply stress to them, and there is a limit to how fine the crystals can be. The vaporized methanol will be recovered using a recovery machine and reused. In the second step, the metal compound crystals are crushed into fine crystals about 1 / 5 of their original size. In other words, the thermal decomposition of the metal compound first breaks down into inorganic or organic matter and metal, then the inorganic or organic matter vaporizes, and after this, the metal molecules gather to form granular metal nanoparticles. Therefore, the size of the metal nanoparticles is about half the size of the metal compound crystals. On the other hand, the finer the metal nanoparticles, the less mass they have, making it more difficult to separate them from the aggregate of metal nanoparticles joined by friction welding. For this reason, the size of the metal compound crystals was reduced to the limit, and the metal nanoparticles precipitated by thermal decomposition were made finer. In addition, by uniformly reducing the size of the metal compound crystals, the size of the metal nanoparticles becomes uniform, and the bonding strength between the metal nanoparticles increases. Therefore, an aggregate of metal compound crystals is filled into a container, a plate is placed over the aggregate of metal compound crystals inside the container, confining the aggregate of metal compound crystals within the container, and the aggregate of metal compound crystals is compressed through the plate. At this time, crystals that are relatively larger are more easily crushed. Therefore, relatively larger crystals are crushed preferentially, and the crushing of crystals progresses as long as the compressive load is applied. Meanwhile, in the aggregate of crystals inside the container, new voids are formed by the crushing of the crystals, and while the compressive load is applied, the crystals move to fill the voids. After this, the applied compressive load is stopped, and impact acceleration is repeatedly applied to the container in three directions: front and back, left and right, and up and down. At this time, the crystals do not scatter because they are confined inside the container by the plate, and the crystals move to fill the voids, and the aggregate of crushed crystals rearranges within the container. Furthermore, after stopping the applied impact acceleration, a compressive load is applied again to the aggregate of crushed crystals through the plate. At this time, the crushing of the previously crushed crystals progresses towards the aggregate of crystals that has become even finer. Next, the container is repeatedly subjected to impact acceleration in three directions to further rearrange the finely milled crystal aggregate. This pair of processes, consisting of applying compressive load and applying impact acceleration in three directions, is repeated. However, as the crystals become finer, it becomes more difficult to apply compressive stress to them even when applying compressive load, and there is a limit to crystal refinement. When the limit of crystal refinement is reached, applying compressive load to the plate material does not further pulverize the crystals, and no movement is observed in the plate material under compressive load. At this point, it is determined that the pulverization of the metal compound crystals is complete, and the pair of processes is stopped. As a result, the size of the crystals is uniformly refined to a size of approximately 20 nm, which is close to 1 / 5 of the size at the time of precipitation. The size of the metal nanoparticles precipitated by the thermal decomposition of the metal compound is approximately 1 / 2 the size of the refined metal compound crystals. The compressive load applied to the plate material is equivalent to 10-50 kgf, depending on the size of the container. The impact acceleration applied to the container is 0.2-0.5 G, depending on the size of the container. In the third step, a second suspension is created in which the microcrystals of individual metal compounds are surrounded by an organic compound. Prior to creating the second suspension, it is necessary to create a first suspension in which the aggregate of metal compound microcrystals is dispersed in an organic compound. For this purpose, an organic compound possessing the following properties is weighed in excess of the aggregate of metal compound microcrystals in the container: firstly, that the metal compound microcrystals do not dissolve or disperse; secondly, that its boiling point is higher than the thermal decomposition temperature of the metal compound; thirdly, that it does not chemically react with the metal particles precipitated at the thermal decomposition temperature of the metal compound; and fourthly, that its viscosity at 20°C is 2-5 mPa·s. The weighed organic compound is then mixed into the container filled with the aggregate of metal compound microcrystals to create the first suspension in which the aggregate of metal compound microcrystals is dispersed in an organic compound. Next, an ultrasonic homogenizer is placed inside the container, and by operating the ultrasonic homogenizer, shock waves are continuously generated in the first suspension. As the shock waves continuously collide with the cluster of fine crystals of the metal compound, the cluster of fine crystals separates into individual crystals, and these separated individual fine crystals are surrounded by the organic compound. Thus, a second suspension is created inside the container, consisting of clusters of individual fine crystals surrounded by the organic compound. In other words, when shock waves are continuously applied to the first suspension by operating an ultrasonic homogenizer, the viscosity of the organic compound becomes low, at 2-5 mPa·s, and the density becomes 0.86-0.87 g / cm³. 3Because the microcrystals of the metal compound are about 20% smaller than those of the metal compound, less of the shock wave is absorbed by the molecular vibrations of the organic compound, and the shock wave is efficiently and continuously applied to the aggregate of metal compound microcrystals via the organic compound. In other words, when an ultrasonic homogenizer is operated in a container, the ultrasonic waves, consisting of compression and rarefaction waves, propagate continuously through the first suspension according to the vibration period of the ultrasonic vibration frequency. As a result, regions of relatively high pressure and relatively low pressure are repeatedly generated, and when this pressure difference exceeds the intermolecular forces of the organic compounds constituting the first suspension, a huge number of cavities (voids), although smaller than the microcrystals of the metal compound, are continuously formed. Furthermore, the melting point of the organic compound is low, ranging from -20°C to 18°C, and the intermolecular forces of the organic compound are small, so cavities (voids) are easily formed. These cavities expand and then contract in the first suspension, and this phenomenon is repeated, causing the cavities to gradually grow. When the cavities expand beyond a certain size, a huge number of cavities collapse in succession. At this time, a tremendous number of shock waves are generated in succession in the first suspension. These shock waves are applied to the aggregate of metal compound microcrystals via the organic compound, and when the shock waves are applied to the areas where the metal compound microcrystals are in direct contact with each other, the metal compound microcrystals have almost no mass, and the bonding force between the contacting microcrystals is extremely small, so the contacting microcrystals easily separate into individual microcrystals. At this time, depending on the viscosity of the organic compound, the organic compound is adsorbed onto the individual microcrystals of the separated metal compound, and the individual microcrystals of the metal compound are covered with the organic compound. After this, the individual microcrystals of the metal compound do not come into direct contact with each other. As a result, the metal compound microcrystals are separated into individual microcrystals in the suspension, and each separated microcrystal is surrounded by the organic compound, creating a second suspension consisting of aggregates of individual microcrystals surrounded by the organic compound. In the fourth step, a third suspension is created in which metal nanoparticles are surrounded by an organic compound. To do this, a heat treatment apparatus is prepared that provides an atmosphere in which the fine crystals of the metal compound are thermally decomposed. A container containing the second suspension is placed in the heat treatment apparatus, and the heat treatment apparatus is heated to a temperature at which the fine crystals of the metal compound are thermally decomposed, and then maintained at the decomposition temperature for a predetermined time. As a result, metal nanoparticles, approximately 10 nm in size, precipitate surrounded by the organic compound, and a third suspension consisting of a collection of metal nanoparticles surrounded by the organic compound is created in the container. In other words, when the thermal decomposition of the refined metal compound crystals begins, first the metal compound decomposes into inorganic or organic matter and metal, and then, as the inorganic or organic matter vaporizes, the metal molecules gather and precipitate as granular particles. The size of these granular metal particles is approximately 10 nm, which is about half the size of the refined metal compound crystals. Furthermore, when the microcrystalline metal compound surrounded by organic compounds undergoes thermal decomposition, metal nanoparticles approximately 10 nm in size precipitate. Although these metal nanoparticles precipitate in an active state, they become inactive after precipitation because they are surrounded by organic compounds. Additionally, during the thermal decomposition of the microcrystalline metal compound, all impurities such as water, organic matter, and hydroxides, which have boiling points lower than the thermal decomposition temperature of the metal compound, vaporize. Therefore, the metal nanoparticles consist solely of metal, and no metal oxides, hydroxides, or compounds with organic matter are present. In the fifth step, an aggregate of metal microparticles is formed by friction welding, continuously joining the internal voids and surface irregularities of the yarn to the surface. To achieve this, first, the yarn, which consists of multiple twisted multifilaments, is continuously drawn from the first bobbin at a drawing speed of 0.2 cm per second. The drawn yarn is then continuously immersed in a third suspension in a container, moved through the third suspension at a speed of 0.2 cm per second, and then continuously pulled out of the third suspension at a pulling speed of 0.2 cm per second. This evenly forms a coating of the third suspension on the surface of the yarn, with a thickness corresponding to the viscosity of the organic compound. In other words, because the yarn, which consists of multiple twisted multifilaments, is continuously drawn from the first bobbin at a slow speed of 0.2 cm per second, the tensile stress applied to the yarn is minimal. Furthermore, because the extracted thread is continuously moved through the third suspension at a slow speed of 0.2 cm per second, the load on the thread is small, and the third suspension, once adsorbed onto the thread's surface, is less likely to fall off. Also, because the movement time within the third suspension is long, the thickness of the third suspension adsorbed onto the thread's surface approaches a uniform thickness. Furthermore, a yarn made by twisting together multiple multifilaments has many voids inside the yarn and many irregularities on the surface of the yarn. On the other hand, the present invention continuously manufactures a conductive yarn in which an aggregate of metal nanoparticles is formed by friction welding continuously bonded to the voids inside the yarn, the irregularities on the surface, and the surface itself. For this reason, a yarn made by twisting together multiple multifilaments is a yarn that conforms to the essence of the present invention. Moreover, a yarn made by twisting together multiple multifilaments has a tensile strength that is significantly greater than the tensile strength of a yarn made of monofilament. For this reason, it has a tensile strength that is significantly greater than that of electrical hard copper wire and electrical hard aluminum wire of the same thickness, and its weight is an order of magnitude less than that of electrical hard copper wire of the same thickness. Next, a cylinder is prepared in advance, having an outer diameter equivalent to 20 times the outer diameter of the core of the first bobbin, a height equivalent to 10 times the height of the core of the first bobbin, and a spiral groove having a width twice the thickness of the thread and a depth five times the thickness of the thread, which is continuously provided from the lower end to the upper end of the side surface at intervals twice the thickness of the thread. Furthermore, the cylinder is placed on a rotating device, the thread pulled up from the third suspension is inserted into the groove at the lower end of the side surface of the cylinder, and then the rotating device is rotated at a peripheral speed of 0.2 cm per second, and the thread pulled up from the third suspension is continuously wound into the groove on the side surface of the cylinder toward the upper end of the groove on the side surface. In other words, the purpose of the fifth step is to form an aggregate of metal nanoparticles that are continuously bonded by frictional pressure welding to the voids inside the thread and the surface irregularities. Therefore, in order to achieve the objective of the fifth step, firstly, it is necessary to prevent the third suspension from peeling off the thread covered with the third suspension wound around the groove on the side of the cylinder. For this reason, the thread pulled up from the third suspension was continuously wound around the groove on the side of the cylinder at a slow speed of 0.2 cm per second. Since the thread covered with the third suspension is only in contact with a groove that is twice the width of the thread and five times the depth of the thread, the third suspension does not peel off the thread. Furthermore, in order to achieve the objective of the fifth step, secondly, when the inside of the chamber is subjected to a negative pressure close to atmospheric pressure, a negative pressure must act on the thread covered with the third suspension. On the other hand, when the yarn covered with the third suspension was wound into the groove on the side of the cylinder at a slow speed of 0.2 cm per second, the yarn covered with the third suspension was only in contact with the groove, which was composed of a width twice the thickness of the yarn and a depth five times the thickness of the yarn, and negative pressure was applied to the yarn covered with the third suspension. To produce this effect, the yarn covered with the third suspension was continuously wound into the groove on the side of the cylinder at a winding speed of 0.2 cm per second. In addition, the width of the groove was made twice the thickness of the yarn to make it easier to wind the yarn covered with the third suspension. Furthermore, the depth of the groove was made five times the thickness of the yarn to make it difficult for the yarn wound in the groove to move. Furthermore, the cylinder is placed inside the chamber of the vacuum impregnation apparatus, the chamber is sealed, and the vacuum pump attached to the vacuum impregnation apparatus is operated to reduce the pressure inside the chamber to a level lower than the vapor pressure of the organic compound. First, the air present in the yarn is discharged out of the chamber, and aggregates of metal nanoparticles surrounded by the organic compound fill both the voids inside the yarn and the irregularities on its surface, and the surface of the yarn is also covered with aggregates of metal nanoparticles surrounded by the organic compound. At this time, all impurities such as water, organic matter, and hydroxides, which have a boiling point lower than the boiling point of the organic compound and were adsorbed in the voids inside the yarn and on the surface, vaporize. Next, the organic compound vaporizes, and the vaporized organic compound is discharged out of the chamber. Because the vapor pressure of the organic compound is a minute vapor pressure of less than one order of magnitude, a large negative pressure close to atmospheric pressure acts on the yarn. As a result, since the metal nanoparticles, which are about 10 nm in size, have almost no mass, the aggregates of metal nanoparticles move at a very high speed, colliding with each other, sequentially moving between the voids inside the cleaned thread and the surface irregularities. Aggregates of metal nanoparticles are then continuously joined by frictional pressure welding to form in the voids inside the thread and the surface irregularities. In other words, the vapor pressure of organic compounds at room temperature is 2-5 Pa for organic compounds with relatively low boiling points, and when these organic compounds vaporize, a large negative pressure close to atmospheric pressure acts on the thread inside the chamber. Furthermore, for organic compounds with relatively high boiling points, the vapor pressure at room temperature is 0.27-0.6 Pa, and when these organic compounds vaporize, an even larger negative pressure close to atmospheric pressure acts on the thread inside the chamber. In addition, since the metal nanoparticles are approximately 10 nm in size, they have almost no mass. Moreover, the size of the surface irregularities of the thread is two orders of magnitude larger than the size of the metal nanoparticles. Therefore, when a large negative pressure close to atmospheric pressure acts on the collection of metal nanoparticles, the almost massless metal nanoparticles move simultaneously towards the voids inside the thread at a very high speed, colliding with each other. At this time, the colliding metal nanoparticles are joined together by frictional pressure welding, and the metal nanoparticles joined by frictional pressure welding sequentially fill the voids inside the thread, the surface irregularities, and the surface at a very high speed. Therefore, a collection of metal nanoparticles is formed by friction welding, continuously joining them to the voids inside the thread and the surface irregularities and surface. As described in the fourth step, the metal nanoparticles are composed solely of metal, and contain no impurities such as metal oxides, hydroxides, or compounds with organic matter. Therefore, the joining of metal nanoparticles by friction welding occurs because they collide with each other at extremely high speeds, and these collisions cause the metals to join directly. As a result, the joining of metal nanoparticles by friction welding has a bonding force close to that of a metallic bond. Furthermore, as the metal nanoparticles sequentially fill the voids inside the thread and the surface irregularities and surface, when metal nanoparticles moving at very high speeds collide with metal nanoparticles that have moved ahead, both parts of the collision site undergo elastic deformation, and the metal nanoparticles join at the elastically deformed parts. Since the elastically deformed parts have a certain area rather than being just points, the bonding force of the metal nanoparticles joined at the elastically deformed parts is increased. Thus, because the metal nanoparticles are joined together by a bonding force that is consistent with their size, once joined, the metal nanoparticles do not easily detach from the group of metal nanoparticles. Furthermore, because the aggregates of metal nanoparticles are continuously joined, the anchoring effect acts not only on the aggregates of metal nanoparticles formed in the internal voids of the yarn, but also on the surface irregularities and the aggregates of metal nanoparticles formed on the surface. In addition, because the metal nanoparticles have almost no mass, the aggregates of metal nanoparticles continuously joined by friction welding are bonded to the internal voids of the yarn, the surface irregularities, and the surface with a certain degree of mechanical strength. Therefore, when creating a fabric or nonwoven fabric using yarn covered with aggregates of metal nanoparticles, even if a load is applied to the metal nanoparticles, the metal nanoparticles are unlikely to separate from the joined aggregates of metal nanoparticles that were joined by friction welding. As a result, the fabric or nonwoven fabric becomes a lightweight conductive film or lightweight conductive sheet with electromagnetic shielding, static electricity, antistatic properties, and electrical conductivity, and is further endowed with the inherent properties of metal, such as excellent thermal conductivity and corrosion resistance. Furthermore, even when tensile stress is applied when conductive threads are used as wire, the metal microparticles are less likely to separate from the aggregate of metal microparticles joined by friction welding. Furthermore, in the fifth step, the speed at which the thread is drawn from the first bobbin, the speed at which the thread moves through the third suspension, the speed at which the thread is pulled up from the third suspension, and the speed at which the thread is wound into the groove on the side of the cylinder are all the same, so the four processes become a continuous process. In the sixth step, the pressure inside the chamber is returned to atmospheric pressure, the cylinder is removed from the chamber, and the thread is continuously drawn out from the grooves provided on the side of the cylinder, while the drawn-out thread is continuously wound onto a second bobbin. As a result, conductive thread is continuously produced. As described above, an anchoring effect acts on the internal voids of the yarn, the surface irregularities, and the aggregate of metal nanoparticles continuously joined by friction welding that fills the surface. Furthermore, because the metal nanoparticles are directly joined to each other by collisions of metal nanoparticles that are completely free of impurities, the bond between the metal nanoparticles has a bonding force close to that of a metallic bond. Moreover, when metal nanoparticles moving at a very high speed collide with metal nanoparticles that have moved ahead, both parts of the collision site undergo elastic deformation, and the metal nanoparticles join to each other at the elastically deformed parts, thus increasing the bonding force between the metal nanoparticles. For this reason, the aggregate of metal nanoparticles joined by friction welding is bonded to the yarn with a certain bonding strength. Consequently, even when stress is applied when processing the conductive yarn into a fabric or nonwoven fabric, the aggregate of metal nanoparticles joined by friction welding does not detach from the surface of the yarn. Furthermore, in the fifth step, a large negative pressure close to atmospheric pressure acts on the cluster of metal nanoparticles in the vacuum chamber, causing the almost massless metal nanoparticles to move simultaneously towards the internal voids of the yarn at a very high speed, colliding with each other. As a result, clusters of metal nanoparticles, continuously joined by friction welding, are formed sequentially in the internal voids, surface irregularities, and surface of the yarn. Therefore, regardless of the fiber material, thickness, or twisting method, clusters of metal nanoparticles, continuously joined by friction welding, are formed in the internal voids, surface irregularities, and surface of the yarn, creating a continuous conductive path through which electric current flows, and enabling the continuous production of yarns with the properties of the metal nanoparticles. Moreover, even if tensile or bending stress is applied during processing of the conductive yarn, the clusters of metal nanoparticles joined by friction welding do not detach from the surface of the yarn, and conductivity is maintained. In addition, because the entire surface of the yarn is covered with metal nanoparticles, the yarn is shielded from the atmosphere and is non-flammable. This solves the three problems described in paragraph 8. On the other hand, the organic compounds and the metal compounds used as raw materials for the metal nanoparticles are common industrial chemicals. Furthermore, all six processes described above are simple. Therefore, using inexpensive raw materials and at low processing costs, the voids inside the yarn, the surface irregularities, and the surface itself can be covered with an aggregate of metal nanoparticles joined by friction welding. This solves all four problems described in paragraph 8. In the manufacture of electric wires with an insulator covering the outside of the conductor, the surface of the yarn is subjected to compressive stress as it is extruded from the die of the extruder. As a result, some of the aggregates of metal nanoparticles formed on the surface of the yarn are peeled off, but the aggregates of metal nanoparticles that have entered the voids inside the yarn and the irregularities on the surface are not peeled off. Furthermore, aggregates of metal nanoparticles remain on the surface of the yarn. Therefore, the aggregates of metal nanoparticles that have entered the voids inside the yarn and the irregularities on the surface of the yarn, and the aggregates of metal nanoparticles that remain on the surface of the yarn, continuously maintain a conductive path through which a continuous current flows, and the yarn acts as a conductor for the electric wire. For this reason, an insulated electric wire can be manufactured using yarn manufactured by this manufacturing method.

[0011] The yarn formed by twisting together multiple multifilaments as described in paragraph 9 is a multifilament made of one of the following fibers: vinylon fiber, nylon 6 fiber, nylon 66 fiber, polyvinyl chloride fiber, polyester fiber, acrylic fiber, polypropylene fiber, polyester fiber, glass fiber, para-aramid fiber, polyacrylonitrile carbon fiber, high-strength polyethylene fiber made of polyethylene with an extremely high molecular weight, polyarylate fiber, poly-paraphenylenebenzoxazole fiber, or high-strength polyvinyl alcohol fiber in which the hydroxyl groups of polyvinyl alcohol are hydrogen-bonded. The yarn formed by twisting together multiple multifilaments made of the above fibers is used as yarn wound on the first bobbin described in paragraph 9, and all six processes described in paragraph 9 are carried out continuously to produce a conductive yarn in which an aggregate of metal nanoparticles is continuously bonded by friction pressure welding to the voids inside the yarn, the surface irregularities, and the surface.

[0012] In other words, a conductive thread is manufactured by filling both the internal voids and surface irregularities of the thread with aggregates of metal nanoparticles, and further covering the surface of the thread with aggregates of metal nanoparticles. Therefore, it is preferable to use a yarn made by twisting together multiple yarns, each consisting of multifilaments with many voids inside and many irregularities on the surface. In other words, the more voids there are inside the yarn and the more irregularities there are on the surface, the greater the anchoring effect acting on the aggregate of metal nanoparticles that fill both the internal voids and the surface irregularities. Furthermore, since the aggregate of metal nanoparticles filling the surface of the yarn is joined to the aggregate of metal nanoparticles that fill the surface irregularities, a large anchoring effect also acts on the aggregate of metal nanoparticles filling the surface of the yarn. In addition, the tensile strength of the multifilament approaches the value obtained by multiplying the tensile strength of the monofilament by the number of twisted monofilaments, and furthermore, the tensile strength of a yarn made by twisting together multiple multifilaments approaches the value obtained by multiplying the tensile strength of the multifilament by the number of twisted multifilaments. As a result, the tensile strength of the yarn becomes significantly greater than that of a copper wire of the same thickness as the yarn. Furthermore, the weight of conductive thread is an order of magnitude less than that of copper wire of the same thickness. Here, although it will be a repetition of what was stated in the first paragraph, we will re-examine the fibers that make up the conductive yarn. Fibers are broadly classified into natural fibers and synthetic fibers based on their material. Natural fibers are further classified into plant fibers and animal fibers based on their material. Many natural fibers have a thermal decomposition temperature lower than the thermal decomposition temperature of the metal compounds that are the raw materials for metal nanoparticles. Therefore, when metal nanoparticles precipitate due to the thermal decomposition temperature of the metal compounds, the thermal decomposition of the fiber has already progressed, and the performance of the fiber deteriorates. This deterioration in fiber performance is an irreversible change. Cotton, a plant fiber, is the only exception, as its thermal decomposition temperature is higher than the thermal decomposition temperature of the metal compounds. However, since cotton is a spun yarn made by twisting short fibers together, it is unsuitable as a yarn for continuously producing conductive yarn. Therefore, natural fibers are unsuitable as fibers for constituting conductive yarn. Chemical fibers are classified into regenerated fibers, semi-synthetic fibers, synthetic fibers, and inorganic fibers based on differences in raw materials and manufacturing methods. Regenerated and semi-synthetic fibers have lower tensile strength than synthetic fibers, making them unsuitable as fibers for continuously producing conductive yarns. Inorganic fibers include glass fibers, carbon fibers, and metal fibers. Carbon fibers have significantly higher tensile strength than glass fibers, but their manufacturing cost is higher. Also, carbon fibers are conductive. Metal fibers are conductive. Therefore, for the production of conductive yarns, yarns made by twisting together multiple multifilaments of glass fibers are suitable. Glass fibers have higher tensile strength than general-purpose synthetic fibers, but they are more expensive, making them suitable for applications requiring high tensile strength for conductive yarns. Furthermore, while polyurethane fibers are a general-purpose synthetic fiber, their tensile strength is 1 / 4 to 1 / 5 that of other general-purpose synthetic fibers, making them unsuitable for use as conductive yarns. Furthermore, high-performance synthetic fibers, such as para-aramid fibers, polyacrylonitrile carbon fibers, high-strength polyethylene fibers made from polyethylene with extremely high molecular weight, polyarylate fibers, poly-paraphenylenebenzoxazole fibers, and high-strength polyvinyl alcohol fibers in which the hydroxyl groups of polyvinyl alcohol are hydrogen-bonded, have a tensile strength an order of magnitude greater than general-purpose synthetic fibers, but are more expensive. Therefore, like glass fibers, they are suitable for applications such as conductive threads that require high tensile strength. Therefore, the multifilament is preferably made of general-purpose synthetic fibers excluding polyurethane fibers, and synthetic fibers consisting of glass fibers and high-performance fibers. Here, the tensile strength and density of various synthetic fibers are described based on Non-Patent Literature 1. The unit of tensile strength of a fiber is cN / dtex, which is specific to the fiber. cN / dtex is the tensile force (centinewtons cN) relative to the fiber thickness (decitex dte x) at which the fiber breaks when a weight is attached to the fiber and the weight is gradually increased. Also, 1 tex is a unit that represents the thickness of a fiber, and it represents the thickness of a fiber that weighs 1 g for a length of 1000 m. Decitex (dtex) is 1 / 10 of 1 tex. Vinylon monofilament has a tensile strength of (2.6 - 3.5) cN / dtex and a density of 1.28 g / cm 3 . 6 nylon monofilament has a tensile strength of (4.2 - 5.7) cN / dtex and a density of 1.14 g / cm 3 . 66 nylon monofilament has a tensile strength of (4.4 - 5.7) cN / dtex and a density of 1.14 g / cm 3 . Polyvinyl chloride monofilament has a tensile strength of (2.4 - 3.3) cN / dtex and a density of 1.39 g / cm 3 . Polyester monofilament has a tensile strength of (3.8 - 5.3) cN / dtex and a density of 1.38 g / cm 3 . Acrylic monofilament has a tensile strength of (3.1 - 4.9c) N / dtex and a density of 1.15 g / cm 3 . Polypropylene monofilament has a tensile strength of (4.0 - 6.6) cN / dtex and a density of 0.91 g / cm 3 . PBT (polyester) monofilament has a tensile strength of (2.6 - 4.4) cN / dtex and a density of 1.31 g / cm 3 . Although there is polyurethane fiber as a synthetic fiber, its tensile strength is 1 / 4 to 1 / 5 that of other chemical fibers, so it is not suitable for use as a thread with conductivity imparted. Furthermore, the relationship between cN / dtex, the unit of tensile strength specific to a fiber, and GPa, the general unit of tensile strength, is given by cN / dtex = (10 / fiber density) × GPa. Therefore, the tensile strength of vinylon monofilament corresponds to (333-448) MPa, nylon 6 monofilament to (479-650) MPa, nylon 66 monofilament to (502-650) MPa, polyvinyl chloride monofilament to (334-459) MPa, polyester monofilament to (524-731) MPa, acrylic monofilament to (357-564) MPa, polypropylene monofilament to (364-601) MPa, and PBT (polyester) monofilament to (341-576) MPa. Furthermore, glass fibers, which belong to the category of inorganic fibers, include glass monofilaments made from E-glass, which have a tensile strength of 3430 MPa, an order of magnitude higher than general-purpose synthetic fibers, and a density of 2.55 g / cm³. 3 Furthermore, high-performance monofilaments made from para-aramid fibers, PAN-based carbon fibers, ultra-high-strength PE fibers, polyarylate fibers, PBO fibers, and ultra-high-strength PVA fibers, like glass fibers, have a tensile strength an order of magnitude greater than the aforementioned general-purpose synthetic fibers, and a density of 1.4-2.0 g / cm³. 3 These fibers are all more expensive than general-purpose synthetic fibers, making them suitable for applications requiring high tensile strength, but unsuitable for general-purpose applications as substitutes for electrical hard copper wire or electrical hard aluminum wire. On the other hand, the tensile strength and tensile elongation of electrical hard copper wire made of tough pitch copper H are specified in JIS C3101. The thinner the wire diameter, the higher the tensile strength, and the tensile strength for wires with diameters from 0.4 mm to 12 mm is specified as 458 MPa or more to 332 MPa or more. Also, the tensile elongation increases with increasing wire diameter, but for electrical hard copper wire with a diameter of 12 mm, the tensile elongation is only 3.12%. In contrast, the tensile elongation of synthetic fiber filaments is an order of magnitude larger than that of electrical hard copper wire. For this reason, synthetic fiber filaments have tensile strength that is comparable to that of electrical hard copper wire. The density of electrical hard copper wire is 8.89 g / cm³. 3 Therefore, a yarn made by twisting together multiple synthetic fibers in a multifilament has significantly higher tensile strength than electrical hard copper wire and weighs an order of magnitude less than electrical hard copper wire of the same thickness. Furthermore, the tensile strength of electrical hard aluminum wire used as a power transmission line is specified in JIS C3002. The thinner the wire diameter, the higher the tensile strength. For wire diameters from 1.6 mm to 5.0 mm, the tensile strength is specified as 186 MPa or higher, or 159 MPa or higher. Also, the tensile elongation increases with increasing wire diameter, but for electrical hard aluminum wire with a diameter of 5.0 mm, the tensile elongation is only 2.0%. In contrast, the tensile elongation of synthetic fiber filaments is an order of magnitude larger than that of electrical hard aluminum wire. Therefore, synthetic fiber filaments have a tensile strength greater than or equal to that of electrical hard copper wire. The density is 2.7 g / cm³. 3 Therefore, the monofilament of the general-purpose synthetic fiber mentioned above has a tensile strength greater than that of hard aluminum wire for electrical applications, and weighs less than 1 / 6 of it. Consequently, a yarn made by twisting together multiple synthetic fiber multifilaments has a significantly higher tensile strength than hard aluminum wire for electrical applications and weighs less than hard aluminum wire of the same thickness. Therefore, the yarn wound on the first bobbin described in paragraph 9 is a yarn made by twisting together multiple multifilaments, and the multifilament is made of one of the following types of fibers: vinylon fiber, nylon 6 fiber, nylon 66 fiber, polyvinyl chloride fiber, polyester fiber, acrylic fiber, polypropylene fiber, polyester fiber, glass fiber, para-aramid fiber, polyacrylonitrile carbon fiber, high-strength polyethylene fiber made of polyethylene with an extremely high molecular weight, polyarylate fiber, poly-paraphenylenebenzoxazole fiber, or high-strength polyvinyl alcohol fiber in which the hydroxyl groups of polyvinyl alcohol are hydrogen-bonded. When a yarn with this configuration is used as the yarn wound on the first bobbin described in paragraph 9, and all six processes described in paragraph 9 are carried out in succession, a conductive yarn is continuously produced in which both the internal voids and surface irregularities of the yarn are filled with aggregates of metal nanoparticles, and the surface of the yarn is further covered with aggregates of metal nanoparticles. This conductive thread has significantly higher tensile strength than electrical hard copper wire and electrical hard aluminum wire, and can be used as a conductor for lightweight electric wires.

[0013] The present invention relates to an inorganic metal compound having a metal complex ion in which molecules or ions made of inorganic matter act as ligands and are coordinately bonded to a metal ion, and an organic compound having four properties as described in paragraph 9, which is a saturated fatty acid ester of any one of methyl decanoate or ethyl decanoate, or methyl dodecanoate or ethyl dodecanoate, that has a first property of having a boiling point higher than 220°C and a second property of having a viscosity of 2-5 mPa·s at 20°C, and the present invention relates to an inorganic metal compound having two properties as described in paragraph 9, and the present invention relates to an organic compound having four properties as described in paragraph 9, and the present invention relates to an organic compound having four properties as described in paragraph 9, and the present invention relates to an inorganic metal compound having two properties as described in paragraph 9, and the present invention relates to an organic compound having one of the saturated fatty acid esters, and the present invention relates to an organic compound having four properties as described in paragraph 9, and the present invention relates to an organic compound having one of the saturated fatty acid esters, which is a saturated fatty acid ester that is

[0014] In other words, when an inorganic metal compound, which consists of an inorganic salt having a metal complex ion in which inorganic molecules or inorganic ions act as ligands and are coordinately bonded to a metal ion, is heat-treated in a reducing atmosphere, the coordination bonds are first broken, and the compound decomposes into inorganic matter and metal. As the temperature is further increased, the inorganic matter absorbs heat of vaporization and vaporizes, and the vaporization of the inorganic matter is completed in the temperature range of 180-220°C, and the metal precipitates. In other words, the smaller the molecular weight of the ligand and the fewer the number of ligands, the lower the temperature at which the coordination bond is broken. Also, the smaller the molecular weight of the ligand, the lower the heat of vaporization of the ligand. Furthermore, the smaller the molecular weight of the inorganic salt, the lower the heat of vaporization of the inorganic substance. The lower the heat of vaporization of the ligand and the lower the heat of vaporization of the inorganic substance, the more easily the inorganic substance vaporizes. One example of such a metal compound is an inorganic metal compound composed of inorganic salts. In other words, among the ions that make up an inorganic metal compound, the metal ion located at the center of the molecule is the largest, and the distance between the metal ion and the ligand is the longest. When this inorganic metal compound is heat-treated in a reducing atmosphere, the coordination bond between the metal ion and the ligand is the first to break, and it decomposes into metal and inorganic matter. As the temperature rises further, the inorganic matter absorbs heat of vaporization and vaporizes, and vaporization of the inorganic matter is completed in the temperature range of 180-220°C, the metal molecules gather to form granular metal nanoparticles, and the thermal decomposition of the inorganic metal compound is complete. The temperature at which the metal precipitates in this inorganic metal compound is the lowest among the temperatures at which metals precipitate due to the thermal decomposition of metal compounds. Therefore, the heat treatment cost is low. In addition, inorganic metal compounds consisting of inorganic salts containing metal complex ions are dispersed in methanol at a concentration of nearly 10% by weight and do not dissolve in methanol. For this reason, inorganic metal compounds can be used as metal compounds that possess both of the properties described in paragraph 9. In other words, metal complex ions, in which inorganic molecules or ions act as ligands and coordinate to metal ions, are easier to synthesize than other metal complex ions. Examples of such metal complex ions include ammine metal complex ions, in which ammonia (NH3) acts as a ligand and coordinates to a metal ion; aqua metal complex ions, in which water (H2O) acts as a ligand and coordinates to a metal ion; and hydroxyl group (OH). ―Hydroxometallic complex ions, such as chloride ions (Cl), where Cl acts as a ligand and forms a coordinate bond with metal ions. - However, or chloride ions (Cl) - Examples include chlorometal complex ions, in which ammonia (NH3) acts as a ligand to coordinate to a metal ion. Furthermore, inorganic metal compounds consisting of inorganic salts such as chlorides, sulfates, and nitrates containing such metal complex ions are easy to synthesize, and because the molecular weight of the inorganic salt is low, the vaporization of the inorganic material is completed and the metal precipitates within a temperature range of 180-220°C. The temperature at which the metal precipitates in these inorganic metal compounds is the lowest among metal compounds because the molecular weight of the ligands in the inorganic metal compound and the molecular weight of the inorganic salt are low. Such inorganic metal compounds are commonly used industrial chemicals. Furthermore, organic compounds that possess four properties—a boiling point higher than the temperature at which inorganic metal compounds undergo thermal decomposition, a viscosity of 2-5 mPa·s at 20°C, the property of not dissolving or dispersing the crystals of inorganic metal compounds, and the property of not chemically reacting with metal nanoparticles precipitated at the thermal decomposition temperature of inorganic metal compounds—include methyl decanoate or ethyl decanoate, or methyl dodecanoate or ethyl dodecanoate. Therefore, these saturated fatty acid esters can be used as organic compounds that possess the four properties described in paragraph 9. Specifically, methyl decanoate CH3(CH2)8COOCH3 has a boiling point of 225°C and a viscosity of 2.14 mPa·s at 20°C. Its melting point is between -14°C and -11°C, and its density is 0.873 g / cm³. 3 Furthermore, the inorganic metal compound crystals do not dissolve or disperse in methyl decanoate. Moreover, they do not chemically react with the metal nanoparticles precipitated by the thermal decomposition of the inorganic metal compound crystals. Note that the vapor pressure at 25°C is only 4.9 Pa, and the negative pressure acting inside the vacuum chamber described in paragraph 9 is close to atmospheric pressure. Ethyl decanoate (CH3(CH2)8COOC2H5) has a boiling point of 242°C and a viscosity of 2.33 mPa·sec at 20°C. Its melting point is -20°C, and its density at 20°C is 0.871 g / cm³. 3Furthermore, the inorganic metal compound crystals do not dissolve or disperse in ethyl decanoate. Moreover, they do not chemically react with the metal nanoparticles precipitated by the thermal decomposition of the inorganic metal compound crystals. Note that the vapor pressure at 20°C is only 2 Pa, and the negative pressure acting inside the vacuum chamber described in paragraph 9 is close to atmospheric pressure. Methyl dodecanoate CH3(CH2) 10 COOCH3 has a boiling point of 262°C and a viscosity of 3.17 mPa·s at 20°C. Its melting point is 5°C, and its density at 20°C is 0.87 g / cm³. 3 Furthermore, the inorganic metal compound crystals do not dissolve or disperse in methyl dodecanoate. Moreover, they do not chemically react with the metal nanoparticles precipitated by the thermal decomposition of the inorganic metal compound crystals. Note that the vapor pressure at 25°C is only 0.55 Pa, and the negative pressure acting inside the vacuum chamber described in paragraph 9 approaches atmospheric pressure. Ethyl dodecanoate CH3(CH2) 10 COOC2H5 has a boiling point of 269°C and a viscosity of 3.38 mPa·s at 20°C. Its melting point is -10°C, and its density is 0.863 g / cm³. 3 Furthermore, the inorganic metal compound crystals do not dissolve or disperse in ethyl dodecanoate. Moreover, they do not chemically react with the metal nanoparticles precipitated by the thermal decomposition of the inorganic metal compound crystals. Note that the vapor pressure at 25°C is only 0.93 Pa, and the negative pressure acting inside the vacuum chamber described in paragraph 9 approaches atmospheric pressure. As explained above, the four types of saturated fatty acid esters can be used as organic compounds that possess the four properties described in paragraph 9. Therefore, by using an inorganic metal compound consisting of an inorganic salt as a metal compound possessing the two properties described in paragraph 9, and by using the aforementioned one type of saturated fatty acid ester as an organic compound possessing the four properties described in paragraph 9, and by continuously carrying out all six processes described in paragraph 9, conductive yarns are continuously produced in which both the voids inside the yarn and the irregularities on the surface are filled with aggregates of metal nanoparticles joined by friction welding, and the surface of the yarn is further covered with aggregates of metal nanoparticles joined by friction welding. Furthermore, the thermal decomposition reaction of yarns made of chemical fibers (excluding inorganic fibers) differs significantly between an atmospheric environment with oxygen gas and a reducing atmosphere. Specifically, thermal decomposition in an atmospheric environment with oxygen gas is due to an oxidation reaction and therefore exothermic. This exothermic phenomenon accelerates the thermal decomposition of yarns made of easily oxidized chemical fibers, and also causes flammable gases produced during the decomposition process to spontaneously ignite. In contrast, thermal decomposition in a reducing atmosphere does not involve oxidation reactions, but rather an endothermic reaction, resulting in no exothermic phenomenon. Therefore, in a reducing atmosphere, the temperature at which yarns made of chemical fibers (excluding inorganic fibers) begin to decompose is delayed compared to an atmospheric environment with oxygen gas and shifts to a higher temperature. On the other hand, synthetic fibers have a material-specific melting point. However, as described in paragraph 9, a negative pressure close to atmospheric pressure acts on the voids inside the thread, the surface irregularities, and the surface itself. This negative pressure causes almost massless metal nanoparticles to move at very high speeds, colliding with each other. In this process, the colliding metal nanoparticles are joined together by frictional pressure welding, and these joined metal nanoparticles then fill the voids inside the thread, the surface irregularities, and the surface itself at very high speeds. In other words, the voids inside the thread, the surface irregularities, and the surface itself are closely packed with metal nanoparticles, each approximately 10 nm in size. Therefore, when a thread made of synthetic fibers is heated to its melting point, it attempts to deform, but this deformation is suppressed by the presence of the closely packed metal nanoparticles. Furthermore, when a thread made of synthetic fibers is heated above its melting point, it attempts to dissolve, but this dissolution is suppressed by the presence of the closely packed metal nanoparticles. As a result, when the thread cools again below its melting point, it returns to its original state. However, when a yarn made of synthetic fibers is heated to the temperature at which it begins to decompose, the yarn begins an irreversible change due to thermal decomposition, and therefore cannot return to its original state. Note that the melting point of synthetic fibers is lower than the temperature at which they begin to decompose. The softening and melting points of various synthetic fibers are as follows: Vinylon monofilament softens at (220-230)°C, but its melting point is unclear. Nylon 6 monofilament has a softening point of 180°C and melts at (215-220)°C. Nylon 66 monofilament has a softening point of (230-235)°C and melts at (250-260)°C. Polyester monofilament has a softening point of (238-240)°C and melts at (255-260)°C. Vinylon monofilament softens at (220-230)°C, but its melting point is unclear. Acrylic monofilament melts at (190-240)°C, but its melting point is unclear. Polyvinyl chloride monofilament melts at (200-210)°C. Vinyldena monofilament melts at (165-185)°C. Polyester monofilament has a softening point of (200-220)°C and melts at (220-230)°C. Polypropylene monofilament has a softening point of (140-160)°C and melts at (165-173)°C. The softening point of vinylon filaments, a polyvinyl alcohol fiber, is 230°C, but the melting point is above the softening point, though its exact location is unclear. Therefore, in an atmospheric environment, thermal decomposition begins once the softening point is exceeded, and the fiber gradually burns while softening and shrinking. On the other hand, in a reducing atmosphere, combustion does not occur, and the temperature at which thermal decomposition begins rises by approximately 50°C. As a result, even if the fiber is heated in a reducing atmosphere, its properties do not change irreversibly as long as the temperature does not exceed 280°C. Consequently, the thermal decomposition temperature of the fiber in a reducing atmosphere is 60-100°C higher than that of inorganic metal compounds. Furthermore, the melting point of nylon 6 monofilament, a polyamide fiber, is 215-220°C. Therefore, in an atmospheric environment, thermal decomposition begins once the melting point is exceeded, and it gradually burns while melting. On the other hand, in a reducing atmosphere, it does not burn, and the temperature at which thermal decomposition begins rises by about 50°C. As a result, even when heated in a reducing atmosphere, the properties of nylon 6 monofilament do not irreversibly change as long as the temperature does not exceed 270°C. For this reason, the thermal decomposition temperature of the fiber in a reducing atmosphere is 45-90°C higher than the thermal decomposition temperature of inorganic metal compounds. Furthermore, the melting point of nylon 66 filaments is 250-260°C. Therefore, in an atmospheric environment, thermal decomposition begins once the melting point is exceeded, and the material gradually burns while melting. On the other hand, in a reducing atmosphere, combustion does not occur, and the temperature at which thermal decomposition begins rises by approximately 60°C. As a result, even if the nylon 66 filament is heated in a reducing atmosphere, the properties of the fiber will not change irreversibly as long as the temperature does not exceed 320°C. For this reason, the thermal decomposition temperature of the fiber in a reducing atmosphere is 90-140°C higher than the thermal decomposition temperature of inorganic metal compounds. Furthermore, acrylic, a polyacrylonitrile fiber, has a monofilament softening point of 190-240°C, and its melting point is above the softening point but unclear. Therefore, in an atmospheric environment, thermal decomposition begins above the softening point, and it gradually burns while melting. On the other hand, in a reducing atmosphere, it does not burn, and the temperature at which thermal decomposition begins rises by about 50°C. Therefore, even if heated in a reducing atmosphere, the properties of the fiber do not irreversibly change as long as the temperature does not exceed 240-290°C. For this reason, the thermal decomposition temperature of the fiber can be raised to 20-110°C higher than the thermal decomposition temperature of inorganic metal compounds in a reducing atmosphere. Furthermore, the melting point of polyester monofilament, a type of polyester fiber, is 255-260°C. Therefore, in an atmospheric environment, thermal decomposition begins once the melting point is exceeded, and it gradually burns while melting. On the other hand, in a reducing atmosphere, combustion does not occur, and the temperature at which thermal decomposition begins rises by approximately 60°C. As a result, in a reducing atmosphere, irreversible changes do not occur unless the temperature exceeds 320°C, and the properties of the fiber remain unchanged. Therefore, the thermal decomposition temperature of the fiber can be raised to 95-140°C higher than the thermal decomposition temperature of inorganic metal compounds in a reducing atmosphere. As explained above, when inorganic metal compounds are thermally decomposed in a reducing atmosphere, the temperature is raised to 180-220°C. However, general-purpose synthetic fibers do not thermally decompose and do not undergo irreversible changes even when heated to 180-220°C.

[0015] The metal compound possessing the two properties described in paragraph 9 is an octyolic acid metal compound in which the oxygen ions constituting the carboxyl group in octyolic acid are covalently bonded to a metal ion, and the organic compound possessing the four properties described in paragraph 9 is a tetradecanoate ester of either methyl tetradecanoate or ethyl tetradecanoate that possesses the first property of having a boiling point higher than 290°C and the second property of having a viscosity of 4-5 mPa·sec at 20°C, and the method of continuously carrying out all the six processes described in paragraph 9 is a method of continuously producing conductive yarn in which an aggregate of metal nanoparticles is formed by friction welding continuously bonded to the voids inside the yarn, the surface irregularities, and the surface.

[0016] In other words, when octoyl octate metal compounds are heat-treated in an air atmosphere, they precipitate metal at 290°C. Furthermore, they disperse in methanol at nearly 10% by weight and are insoluble in methanol. Therefore, octoyl octate metal compounds can be used as metal compounds possessing both of the properties described in paragraph 9. Note that when octoyl octate metal compounds are heat-treated in a reducing atmosphere or a nitrogen atmosphere, they precipitate metal at 340°C, 50°C higher than in an air atmosphere. In other words, among the ions that make up octoyl acid metal compounds, the metal ion is the largest. Therefore, in octoyl acid metal compounds in which the oxygen ions constituting the carboxyl group of octoic acid are covalently bonded to the metal ion, the distance between the oxygen ions constituting the carboxyl group and the metal ion is longer than the distance between other ions. When octoyl acid metal compounds with these molecular structural characteristics are heat-treated in an atmospheric environment, once the temperature exceeds the boiling point of octoic acid (228°C), the bond between the oxygen ions constituting the carboxyl group and the metal ion is the first to break, separating the octoic acid from the metal. Furthermore, because octoic acid is a saturated fatty acid, it does not have an unsaturated structure in which carbon atoms are in excess of hydrogen atoms. As a result, the octoic acid absorbs heat of vaporization and vaporizes, completing vaporization at 290°C. The metal molecules then aggregate to form granular metal nanoparticles, and the octoyl acid metal compound completes its thermal decomposition. In other words, the carboxylate anion (R-COO) of a carboxylic acid composed of saturated fatty acids - However, carboxylic acid metal compounds that covalently bond with metal ions precipitate metal upon thermal decomposition. Among these carboxylic acid metal compounds, in order from the lowest thermal decomposition temperature at which metal precipitates, are octoyl phosphate metal compounds, laurate metal compounds, and stearate metal compounds. Therefore, by using octoyl phosphate metal compounds, which have the lowest thermal decomposition temperature, the third suspension described in paragraph 9 can be produced inexpensively. Note that laurate metal compounds and stearate metal compounds, like octoyl phosphate metal compounds, disperse in methanol at a concentration of nearly 10% by weight and do not dissolve in methanol. In other words, the boiling point of lauric acid is 296°C, which is the temperature at which the thermal decomposition of metal laurate compounds in an atmospheric environment is completed (360°C). However, the thermal decomposition temperatures of metal laurate compounds and metal stearate compounds are higher than those of metal octoate compounds, so it is preferable to use metal octoate compounds as the raw material for depositing metal. Furthermore, carboxylic acid metal compounds composed of unsaturated fatty acids have an excess of carbon atoms relative to hydrogen atoms compared to carboxylic acid metal compounds composed of saturated fatty acids. Therefore, thermal decomposition causes metal oxides to precipitate simultaneously, such as cuprous oxide (Cu2O) and cupric oxide (CuO) in the case of copper oleate. This requires processing costs to reduce cuprous oxide and cupric oxide back to copper. In particular, cuprous oxide needs to be oxidized to cupric oxide in an oxygen-rich atmosphere rather than an atmospheric atmosphere, and then further reduced to copper in a reducing atmosphere, which increases processing costs. Furthermore, metal octoates are inexpensive industrial chemicals that can be easily synthesized. Specifically, reacting octic acid with an alkali metal produces alkali metal octoates. Subsequently, reacting these alkali metal octoates with inorganic metal compounds produces metal octoates composed of various metals. Also, octic acid is a commonly used organic acid. Therefore, metal octoates are the cheapest organometallic compounds among organometallic compounds. For this reason, although their thermal decomposition temperature is higher than that of complexes composed of inorganic metal compounds, as explained in paragraph 11, they are still cheaper metal compounds than complexes composed of inorganic metal compounds. On the other hand, an organic compound that possesses four properties—a boiling point higher than the temperature at which the aforementioned octoate metal compound undergoes thermal decomposition, a viscosity of 4-5 mPa·s at 20°C, the property of not dissolving or dispersing the crystals of the octoate metal compound, and the property of not chemically reacting with the metal nanoparticles precipitated at the thermal decomposition temperature of the octoate metal compound—is either methyl tetradecanoate or ethyl tetradecanoate ester. Therefore, these tetradecanoate esters can be used as organic compounds that possess the four properties described in paragraph 9. In other words, methyl tetradecanoate CH3(CH2) 12 COOCH3 has a boiling point of 323°C and a viscosity of 3.98 mPa·s at 25°C. Its melting point is 18°C, and its density at 25°C is 0.855 g / cm³. 3Furthermore, the octoyl octoate metal compound crystals do not dissolve or disperse in methyl tetradecanoate. Moreover, they do not chemically react with the metal nanoparticles precipitated by the thermal decomposition of the octoyl octoate metal compound crystals. The vapor pressure at 25°C is only 0.65 Pa, and the negative pressure acting inside the vacuum chamber described in paragraph 9 is close to atmospheric pressure. Ethyl tetradecanoate CH3(CH2) 12 COOC2H5 has a boiling point of 309°C and a viscosity of 4.75 mPa·s at 20°C. Its melting point is 12°C, and its density is 0.86 g / cm³. 3 Furthermore, the octoyl octoate metal compound crystals do not dissolve or disperse in ethyl tetradecanoate. Moreover, they do not chemically react with the metal nanoparticles precipitated by the thermal decomposition of the octoyl octoate metal compound crystals. Note that the vapor pressure at 25°C is only 0.27 Pa, and the negative pressure acting inside the vacuum chamber described in paragraph 9 is close to atmospheric pressure. As explained above, the two types of tetradecanoate esters can be used as organic compounds possessing the four properties described in paragraph 9. Therefore, by using an octylate metal compound as a metal compound possessing the two properties described in paragraph 9, and using the aforementioned one type of tetradecanoate ester as an organic compound possessing the four properties described in paragraph 9, and by continuously carrying out all six processes described in paragraph 9, conductive yarns are continuously produced in which both the internal voids and surface irregularities of the yarn are filled with aggregates of metal nanoparticles joined by friction welding, and the surface of the yarn is further covered with aggregates of metal nanoparticles joined by friction welding. Here, we compare the melting point and thermal decomposition temperature of synthetic fibers, known as high-performance fibers, with the thermal decomposition temperature of metal octoates. Note that metal octoates decompose at 290°C in an atmospheric environment. Monofilaments of aromatic nylon fibers, which belong to the category of synthetic fibers, do not soften or melt, but gradually decompose and carbonize at 400-430°C in an atmospheric environment. On the other hand, they do not burn in a reducing atmosphere, and the temperature at which thermal decomposition begins rises. The temperature at which thermal decomposition begins in an atmospheric environment is 110-140°C higher than the thermal decomposition temperature of metal octoates. Therefore, even if metal octoates decompose, the filaments of aromatic nylon fibers do not. Fluorine-based monofilaments, which belong to the synthetic fiber category, have a melting point of 327°C, a tensile strength of 110-280 MPa, and a density of 1.74-2.15 g / cm³. 3 Therefore, in an atmospheric environment, thermal decomposition begins once the melting point is exceeded, and combustion gradually occurs while melting. For this reason, the monofilament of fluorine-based fibers begins to decompose at a temperature 40°C higher than the thermal decomposition temperature of the metal octylate compound. For this reason, even if the metal octylate compound decomposes, the filament of the aromatic nylon fiber does not. Para-aramid monofilaments, which belong to the synthetic fiber category, have an unclear melting point, a high thermal decomposition onset temperature of approximately 510°C, a high tensile strength of 2.9-3.4 GPa, and a density of 1.44 g / cm³. 3 Therefore, the temperature at which thermal decomposition begins in an atmospheric environment is nearly 220°C higher than the thermal decomposition temperature of the metal octylate compound. For this reason, even if the metal octylate compound undergoes thermal decomposition, the monofilament of the para-aramid fiber does not. Meta-aramid monofilaments, which belong to the synthetic fiber category, have a thermal decomposition onset temperature of approximately 400°C, a tensile strength of 588-686 MPa, and a density of 1.38 g / cm³. 3 Therefore, the temperature at which thermal decomposition begins in an atmospheric environment is nearly 110°C higher than the thermal decomposition temperature of the metal octylate compound. For this reason, even if the metal octylate compound undergoes thermal decomposition, the monofilament of the meta-aramid fiber does not. Monofilaments of PBO (poly(p-phenylenebenzoxazole)) fibers, which belong to the synthetic fiber category, have an unclear melting point, a high thermal decomposition onset temperature of 650°C, a high tensile strength of 5.8 GPa, and a density of 1.54 g / cm³. 3Therefore, the temperature at which thermal decomposition begins in an atmospheric environment is 360°C higher than the thermal decomposition temperature of the metal octyl Polyarylate monofilaments, which belong to the synthetic fiber category, have an unclear melting point, a thermal decomposition onset temperature exceeding 400°C, high tensile strengths of 2.9-3.3 GPa, and a density of 1.41-1.45 g / cm³. 3 Therefore, the temperature at which thermal decomposition begins in an atmospheric environment is nearly 110°C higher than the thermal decomposition temperature of the metal octyl phosphate compound. For this reason, even if the metal octyl phosphate compound undergoes thermal decomposition, the monofilament of the polyarylate fiber does not. On the other hand, glass fiber monofilaments, which belong to the inorganic fiber category, have an extremely high softening point of 840°C, a high tensile strength of 3.4 GPa, and a density of 2.55 g / cm³. 3 Therefore, its softening point is nearly 550°C higher than the thermal decomposition temperature of the metal octyl As explained above, when octoyl octate metal compounds are thermally decomposed in an atmospheric environment, the temperature rises to 290°C, but synthetic fibers known as high-performance fibers do not undergo irreversible changes. However, they are more expensive than the general-purpose synthetic fibers described in paragraph 14. Therefore, they are used in applications where high tensile strength is required and conductivity is imparted, which cannot be achieved with general-purpose synthetic fibers. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic, magnified view of an aggregate of copper nanoparticles surrounded by methyl decanoate. [Figure 2] This diagram schematically shows, using a cross-section of the thread, how the internal voids of a sewing thread are filled with aggregates of bonded copper particles. [Modes for carrying out the invention]

[0018] Example 1 This example describes the production of an aggregate of metal nanoparticles surrounded by an organic compound. In this example, an aggregate of copper nanoparticles surrounded by an organic compound is produced. The raw material for the copper nanoparticles belongs to the inorganic metal compounds described in paragraph 12, and is one of the easiest copper complex ions to synthesize, consisting of four ammines and copper ions Cu. 2+ Tetraamminecopper ions [Cu(NH3)4] coordinately bonded to it. 2+ Tetraamminecopper nitrate [Cu(NH3)4](NO3)2 (for example, a product of Mitsuwa Chemical Co., Ltd.), which is a nitrate of copper, was used. Tetraamminecopper nitrate undergoes complete thermal decomposition at 200°C in a reducing atmosphere, precipitating copper. In addition, methyl decanoate (for example, a product of Fujifilm Wako Pure Chemical Industries, Ltd.), described in paragraph 11, was used as the organic compound. Methyl decanoate has a boiling point of 225°C and a viscosity of 2.14 mPa·sec at 20°C. Its melting point is between -14°C and -11°C, and its density is 0.873 g / cm³. 3 That is the case. 125 g (equivalent to 0.5 moles) of tetraamminecopper nitrate was dispersed in 1.8 L of methanol and stirred to prepare a methanol dispersion of tetraamminecopper nitrate. The methanol dispersion was then heated to 65°C, vaporizing the methanol and precipitating tetraamminecopper nitrate crystals. Next, the tetraamminecopper nitrate crystals were transferred to a 15cm x 15cm x 2cm container. Then, a 15cm x 15cm x 1cm plate was placed over the tetraamminecopper nitrate crystals, and nine 2kg weights were placed on the plate at equal intervals. After removing the weights, impact accelerations of 0.3G were repeatedly applied to the sides and bottom of the container in three directions: front / back, left / right, and up / down. After repeating this process of applying compressive load and impact acceleration five times, the weights were placed back on the plate, but the plate did not move at all, so the process was stopped. After this, the plate was removed from the container. Next, 149g (equivalent to 0.8 moles) of methyl decanoate was mixed into the container. Furthermore, The horn of an ultrasonic homogenizer (LUH300, a product of Yamato Scientific Co., Ltd.) was immersed in a container, and 20 kHz ultrasonic vibrations were applied to the methyl decanoate in the container for 2 minutes to create a suspension in which individual tetraamminecopper nitrate crystals were dispersed in methyl decanoate. Furthermore, the container containing the suspension was moved to a heat treatment device with a hydrogen atmosphere, where the container was heated to 200°C and left at 200°C for 2 minutes. After this, a portion of the sample was removed from the container. Next, the sample was observed and analyzed using an electron microscope. The electron microscope used was an ultra-low acceleration voltage SEM from JFE Techno-Research Corporation. This device allows surface observation using ultra-low acceleration voltages starting from 100 volts and has the advantage of allowing direct observation of the sample surface without forming a conductive coating on the sample. Secondary electron beams between 900-1000 volts from the backscattered electron beam of the sample were extracted and imaged. The sample consisted of fine particles approximately 10 nm in size dispersed around organic matter. Furthermore, a portion of the sample was heated to 230°C in a reducing atmosphere to vaporize methyl decanoate, and the material of the fine particles was analyzed again using an electron microscope. As a result, the fine particles were found to be copper particles. Therefore, the prepared sample is a suspension in which copper nanoparticles, approximately 10 nm in size, are dispersed surrounded by methyl decanoate. Figure 1 schematically shows a magnified view of the aggregate of copper nanoparticles surrounded by methyl decanoate. 1 represents copper nanoparticles, and 2 represents ethyl decanoate.

[0019] Example 2 In this example, the suspension prepared in Example 1 is used to cover sewing thread made of nylon 66, one of the most common synthetic fibers, with an aggregate of copper microparticles. Furthermore, the tensile strength of 66 nylon monofilament is (4.4-5.7) cN / dtex, which corresponds to (502-650) MPa. Also, as described in paragraph 8, the tensile strength of electrical hard copper wire made from tough pitch copper H is 458 MPa or higher to 332 MPa or higher for wire diameters from 0.4 mm to 12 mm. Therefore, the tensile strength of yarn made from 66 nylon monofilament is higher than that of copper wire made from tough pitch copper H. Consequently, the tensile strength of sewing thread made by twisting multiple multifilaments of 66 nylon is significantly higher than that of electrical hard copper wire. Moreover, the tensile strength of sewing thread in which the internal voids and surface irregularities are filled with aggregates of copper particles, and the surface of the sewing thread is covered with aggregates of copper particles, will be even higher. Additionally, the density of 66 nylon monofilament is 1.14 g / cm³. 3 The density of copper is 8.89 g / cm³. 3 Therefore, the density of 66 nylon monofilament is close to 1 / 8 that of copper. As a result, conductive sewing thread weighs an order of magnitude less than electrical hard copper wire of the same thickness. The sewing thread used, made of 66 nylon multifilament, is thin, with a thickness of 0.2 mm, and has a 110 dtex / 1×2 configuration. It has a tensile strength of 1130 cN (a force equivalent to 1.15 kgf) and a tensile elongation of 27%. The "1×2" indicates the number of strands, meaning that one strand is initially twisted, and then two of these twisted strands are combined and twisted in the opposite direction to the initial twist. The sewing thread is wound on the core of a bobbin with an outer diameter of 4 cm and a height of 5 cm. Additionally, a cylinder with an outer diameter of 80 cm and a height of 50 cm was prepared, with spiral grooves 0.4 mm wide and 1 mm deep, spaced 2 mm apart, running from the lower end to the upper end of the side of the cylinder. Next, the sewing thread was continuously pulled out from the bobbin at a pulling speed of 0.2 cm per second, and the pulled-out sewing thread was continuously immersed in the suspension prepared in Example 1. Furthermore, it was continuously moved through the suspension at a movement speed of 0.2 cm per second, and then continuously pulled out of the suspension at a pulling speed of 0.2 cm per second. Furthermore, the cylinder was placed on a rotating device, and the thread pulled up from the third suspension was inserted into a groove at the lower end of the side of the cylinder. Then, the rotating device was rotated at a peripheral speed of 0.2 cm per second, and the thread pulled up from the third suspension was continuously wound into the groove on the side of the cylinder toward the upper end of the side. Next, the cylinder was moved from the rotating device into the chamber of the vacuum impregnation device. Furthermore, after reducing the vacuum level using the rotary vacuum pump attached to the vacuum impregnation device, the pressure inside the chamber was further reduced to 4 Pa ​​using a turbomolecular pump. After this, the pressure inside the chamber was returned to atmospheric pressure, the cylinder was removed from the chamber, and sewing thread was continuously pulled out from the grooves provided on the side of the cylinder, while the pulled-out sewing thread was continuously wound onto a bobbin. A portion of the prepared sample was cut out, and the cut-out sample was further cut. The cross-section of the sample was observed and analyzed using the electron microscope used in Example 1. The sample consisted of copper nanoparticles, each approximately 10 nm in size, bonded together. These bonded copper nanoparticles were stacked to form a multilayer structure with a thickness of approximately 100 nm, covering the surface of the sewing thread. Furthermore, the voids inside the sewing thread and the surface irregularities were filled with these bonded copper nanoparticles. Figure 2 schematically shows, using a cross-section of the sewing thread, the state in which the voids inside the sewing thread 3 are filled with the bonded copper nanoparticles 4. Furthermore, using a DC resistance meter (for example, Tsuruga Electric Co., Ltd.'s DC resistance meter Model 356H), terminals were attached to four points on the cut sewing thread, and DC current was passed through the thread in different directions. The voltage was measured twice at the two inner terminals, and the resistance value obtained by dividing the difference between these two voltage values ​​by the current value measured at the two outer terminals showed a volume resistivity close to that of copper. Furthermore, repeated measurements of the tensile strength based on the JIS L1095 thread tensile strength test revealed a tensile strength of 4.0 ± 0.2 kgf. This value is close to 3.5 times the tensile strength of sewing thread. The bonded copper microparticles filled the internal voids and surface irregularities of the sewing thread, covering the thread's surface and increasing its tensile strength. Therefore, the thread produced in this embodiment possesses the electrical and thermal conductivity of copper, has significantly increased tensile strength compared to copper wire of the same thickness, and can be used as a conductor with a weight an order of magnitude less.

[0020] Example 3 This embodiment uses the suspension prepared in Example 1 to coat a sewing thread made of polyester, one of the most common synthetic fibers, with an aggregate of copper microparticles. This sewing thread is thick, with a diameter of 1 mm, a composition of 167 dtex / 2×3, a tensile strength of 6070 cN (a force equivalent to 6.19 kgf), and a tensile elongation of 21%. The 2×3 indicates the number of strands, meaning that two strands are initially twisted, these three under-twisted strands are combined, and an over-twist is applied in the opposite direction to the under-twist. The polyester sewing thread used in this embodiment has 5.4 times the tensile strength of the 66 nylon sewing thread used in Example 2 because it has a larger number of both under-twisted and over-twisted strands. Furthermore, its tensile elongation is 21%, which is lower than that of the 66 nylon sewing thread. Polyester monofilament has a tensile strength of (3.8-5.3) cN / dtex, which corresponds to (524-731) MPa. On the other hand, as described in paragraph 8, the tensile strength of electrical hard copper wire made of tough pitch copper H is 458 MPa or more and 332 MPa or more for wire diameters from 0.4 mm to 12 mm. Therefore, the tensile strength of yarn made of multifilament is higher than that of copper wire made of tough pitch copper H. Consequently, the tensile strength of sewing thread made by twisting multiple multifilaments is significantly higher than that of electrical hard copper wire. Furthermore, the tensile strength of sewing thread in which the internal voids and surface irregularities are filled with aggregates of copper nanoparticles and the surface of the sewing thread is covered with aggregates of copper nanoparticles will be even higher. Also, the density of polyester monofilament is 1.38 g / cm³. 3 The density of copper is 8.89 g / cm³. 3 Therefore, the density of polyester monofilament is close to 1 / 6.5 that of copper. As a result, conductive sewing thread weighs an order of magnitude less than electrical copper wire of the same thickness. Polyester sewing thread is wound around a bobbin core with an outer diameter of 6 cm and a height of 8 cm. For this purpose, a cylinder was prepared with an outer diameter of 120 cm and a height of 80 cm, into which spiral grooves 2 mm wide and 5 mm deep were made at 2 mm intervals from the lower end to the upper end of the side of the cylinder. Next, the sewing thread was continuously pulled out from the bobbin at a pulling speed of 0.2 cm per second, and the pulled-out sewing thread was continuously immersed in the suspension prepared in Example 1. Furthermore, it was continuously moved through the suspension at a movement speed of 0.2 cm per second, and then continuously pulled out of the suspension at a pulling speed of 0.2 cm per second. Furthermore, the cylinder was placed on a rotating device, and the thread pulled up from the third suspension was inserted into a groove at the lower end of the side of the cylinder. Then, the rotating device was rotated at a peripheral speed of 0.2 cm per second, and the thread pulled up from the third suspension was continuously wound into the groove on the side of the cylinder toward the upper end of the side. Next, the cylinder was moved from the rotating device into the chamber of the vacuum impregnation device, the chamber was sealed, the vacuum level was reduced using a rotary vacuum pump attached to the vacuum impregnation device, and then the pressure inside the chamber was further reduced to 4 Pa ​​using a turbomolecular pump. After this, the pressure inside the chamber was returned to atmospheric pressure, the cylinder was removed from the chamber, and sewing thread was continuously pulled out from the grooves provided on the side of the cylinder, while the pulled-out sewing thread was continuously wound onto a bobbin. A portion of the prepared sample was cut out, and the cut-out sample was further cut. The cross-section of the sample was observed and analyzed using the electron microscope used in Example 1. Similar to Example 2, the sample consisted of copper nanoparticles approximately 10 nm in size bonded together, and these bonded copper nanoparticles were stacked to form a multilayer structure with a thickness of approximately 100 nm, covering the surface of the sewing thread. In addition, the voids inside the sewing thread and the surface irregularities were filled with aggregates of copper nanoparticles approximately 10 nm in size. Furthermore, similar to Example 2, a DC resistance meter was used to attach terminals to four locations on the cut sewing thread. DC current was passed through the sewing thread in different directions, and the voltage was measured twice at the two inner terminals. The resistance value obtained by dividing the difference between these two voltage values ​​by the current value measured at the two outer terminals showed a volume resistivity close to that of copper. Furthermore, repeated measurements of the tensile strength based on the JIS L1095 thread tensile strength test revealed a tensile strength of 25 ± 0.4 kg. This value is nearly four times that of sewing thread. The bonded copper microparticles filled the internal voids and surface irregularities of the sewing thread, covering the thread's surface and increasing its tensile strength. Therefore, the thread produced in this embodiment possesses the electrical and thermal conductivity of copper, has significantly increased tensile strength compared to a copper wire of the same thickness, and can be used as a conductor with a weight an order of magnitude less.

[0021] The above example demonstrates the use of sewing thread made from two types of synthetic fibers, where the internal voids and surface irregularities of the sewing thread are filled with aggregates of copper nanoparticles, and the surface of the sewing thread is covered with aggregates of copper nanoparticles. However, the thread is not limited to sewing thread, nor is the material limited to 66 nylon and polyester; it can be used as a multifilament thread made from long fibers of various materials. In other words, since multifilament threads made from long fibers have internal voids and surface irregularities, the same method as in this example can be used to fill the internal voids and surface irregularities of threads of various materials with aggregates of copper nanoparticles and cover the surface of the thread with aggregates of copper nanoparticles. Furthermore, the metal nanoparticles are not limited to copper nanoparticles. For example, if the nanoparticles are made of aluminum, the conductivity will be halved compared to copper, but since the density is one-third that of copper, the weight of the conductive cotton thread can be further reduced. Moreover, if the nanoparticles are made of nickel, the thread will have ferromagnetic properties and will be magnetically attracted to magnetic materials. [Explanation of Symbols]

[0022] 1. Copper microparticles 2. Methyl decanoate 3. Sewing thread 4. Copper microparticles

Claims

1. A method for continuously manufacturing conductive threads in which an aggregate of metal nanoparticles is formed by friction welding to the internal voids and surface irregularities of the thread is as follows: The first step involves dispersing a metal compound in methanol that possesses both the first property of being dispersed in methanol but not soluble in methanol, and the second property of precipitating metal by thermal decomposition, to create a methanol dispersion of the metal compound; then, vaporizing methanol from the methanol dispersion of the metal compound to precipitate an aggregate of crystals of the metal compound having a size of approximately 100 nm; and finally, filling the aggregate of crystals of the metal compound into a container. A plate material is placed over the entire surface of the aggregate of metal compound crystals in the container. After this, a compressive load is applied to the entire surface of the plate material to pulverize the metal compound crystals in the container. Furthermore, impact acceleration in three directions (front / back, left / right, and up / down) is repeatedly applied to the sides and bottom of the container to rearrange the pulverized aggregate of metal compound crystals within the container. After this, the compressive load is applied again to the entire surface of the plate material to further pulverize the metal compound crystals. Furthermore, the impact acceleration in the three directions is repeatedly applied again to the sides and bottom of the container. This pair of processes, consisting of applying the compressive load and applying the impact acceleration, is repeated. When the plate material stops moving when the compressive load is applied, it is determined that the pulverization of the metal compound crystals is complete, and the pair of processes is stopped. As a result, the metal compound crystals are pulverized into fine crystals of 1 / 5 of their original size. After this, the plate material is removed from the container. An organic compound possessing the following four properties is weighed in an amount greater than the aggregate of fine crystals of the metal compound in the container: first, the metal compound crystals do not dissolve or disperse; second, the boiling point is higher than the thermal decomposition temperature of the metal compound; third, the metal fine particles precipitated at the thermal decomposition temperature of the metal compound do not react chemically; and fourth, the viscosity at 20°C is 2-5 mPa·s. The weighed organic compound is then mixed into the container filled with the aggregate of fine crystals of the metal compound. As a result, the aggregate of fine crystals of the metal compound is made to possess the four properties of the organic compound. A first suspension is created in which the metal compound is dispersed. Further, an ultrasonic homogenizer is placed in the container, and by operating the ultrasonic homogenizer, shock waves are continuously generated in the first suspension. The shock waves continuously collide with the cluster of fine crystals of the metal compound, separating the cluster of fine crystals into individual fine crystals. Each of these separated individual fine crystals is surrounded by the organic compound, and a second suspension consisting of the cluster of individual fine crystals surrounded by the organic compound is created in the container. After this, the ultrasonic homogenizer is removed from the container in a third step. A heat treatment apparatus is prepared, comprising an atmosphere that causes thermal decomposition of the fine crystals of the metal compound. The container is placed in the heat treatment apparatus, the heat treatment apparatus is heated to a temperature at which the fine crystals of the metal compound decompose, and then maintained at this decomposition temperature for a predetermined time. As a result, metal nanoparticles approximately 10 nm in size precipitate, surrounded by the organic compound, and a third suspension consisting of the collection of metal nanoparticles surrounded by the organic compound is created in the container. After this, the container is removed from the heat treatment apparatus in a fourth step. The thread, which consists of multiple multifilaments twisted together, is wound on a first bobbin, and the thread is continuously drawn out at a drawing speed of 0.2 cm per second. The drawn thread is then continuously immersed in a third suspension in the container, and further moved through the third suspension at a movement speed of 0.2 cm per second. After this, the thread is continuously pulled out of the third suspension at a pulling speed of 0.2 cm per second. Next, the thread has an outer diameter 20 times the outer diameter of the core of the first bobbin and a height 10 times the height of the core of the first bobbin, and the A cylinder is prepared in advance, having spiral grooves that are twice the width of the thread and five times the depth of the thread, and are provided continuously from the lower end to the upper end of the side surface at intervals twice the width of the thread. The cylinder is then placed on a rotating device, and the thread pulled up from the third suspension is inserted into the groove at the lower end of the side surface of the cylinder. After this, the rotating device is rotated at a peripheral speed of 0.2 cm per second, and the thread pulled up from the third suspension is continuously wound into the groove at the upper end of the side surface of the cylinder. After this, the cylinder is moved from the rotating device. The yarn is transferred into the chamber of the vacuum impregnation device, the chamber is sealed, and the vacuum pump attached to the vacuum impregnation device is operated to reduce the pressure inside the chamber to a pressure lower than the vapor pressure of the organic compound. As a result, first, the air present in the yarn is discharged to the outside of the chamber, and the aggregate of metal particles surrounded by the organic compound enters both the voids inside the yarn and the irregularities on its surface, and the aggregate of metal particles surrounded by the organic compound covers the surface of the yarn. Next, the organic compound vaporizes, and the vaporized organic compound The composite is discharged outside the chamber, and as a result, because the vapor pressure of the organic compound is a minute vapor pressure of less than one order of magnitude, a negative pressure close to atmospheric pressure acts on the thread, and because the metal nanoparticles, which are about 10 nm in size, have almost no mass, the aggregate of metal nanoparticles moves at a very high speed while colliding with each other, and the aggregate of metal nanoparticles sequentially fills the voids inside the thread, the surface irregularities and the surface, and aggregates of metal nanoparticles that are continuously joined by frictional pressure welding are formed on the voids inside the thread, the surface irregularities and the surface, in the fifth step, The sixth step involves returning the pressure inside the chamber of the vacuum impregnation apparatus to atmospheric pressure, removing the cylinder from the chamber, continuously drawing out the thread from a groove provided on the side of the cylinder, and continuously winding the drawn-out thread onto a second bobbin. A method for continuously producing conductive yarn is one in which all six processes described above are carried out in a continuous manner, and an aggregate of metal nanoparticles is formed by friction welding to the voids inside the yarn, the irregularities on its surface, and the surface itself.

2. A method for continuously producing a conductive yarn in which an aggregate of metal nanoparticles is formed by friction welding to the internal voids and surface irregularities of the yarn, wherein the yarn formed by twisting together a plurality of multifilaments according to claim 1 is a multifilament made of one of the following fibers: vinylon fiber, nylon 6 fiber, nylon 66 fiber, polyvinyl chloride fiber, polyester fiber, acrylic fiber, polypropylene fiber, polyester fiber, glass fiber, para-aramid fiber, polyacrylonitrile carbon fiber, high-strength polyethylene fiber made of polyethylene with an extremely high molecular weight, polyarylate fiber, poly-paraphenylenebenzoxazole fiber, or high-strength polyvinyl alcohol fiber in which the hydroxyl groups of polyvinyl alcohol are hydrogen-bonded, wherein the yarn formed by twisting together a plurality of multifilaments made of the same fibers is used as a yarn wound on the first bobbin according to claim 1, and all six processes according to claim 1 are carried out continuously, wherein an aggregate of metal nanoparticles is formed by friction welding to the internal voids and surface irregularities of the yarn.

3. The present invention relates to an inorganic metal compound having two properties as described in claim 1, which is an inorganic salt having a metal complex ion in which molecules or ions made of inorganic matter act as ligands and are coordinately bonded to a metal ion, and the organic compound having four properties as described in claim 1, which is a saturated fatty acid ester of any one of methyl decanoate or ethyl decanoate, or methyl dodecanoate or ethyl dodecanoate, which has a first property of having a boiling point higher than 220°C and a second property of having a viscosity of 2-3 mPa·s at 20°C, and the present invention relates to an inorganic metal compound having two properties as described in claim 1, which is a saturated fatty acid ester of any one of the four properties as described in claim 1, and the present invention relates to an organic compound having four properties as described in claim 1, and the present invention relates to a method of continuously carrying out all six steps of the process described in claim 1, which is a method of continuously producing a conductive yarn in which an aggregate of metal fine particles is formed by friction welding continuously bonded to the voids inside the yarn and the surface irregularities and surface.

4. A method for continuously producing conductive yarn in which an aggregate of metal nanoparticles, formed by friction welding, is created by continuously bonding the internal voids and surface irregularities of the yarn to a metal ion, the metal compound possessing the two properties described in claim 1 being an octic acid metal compound in which the oxygen ions constituting the carboxyl group in octic acid are covalently bonded to a metal ion, the organic compound possessing the four properties described in claim 1 being a tetradecanoate ester of either methyl tetradecanoate or ethyl tetradecanoate, the metal compound possessing the two properties described in claim 1 being the metal compound possessing the two properties described in claim 1, the tetradecanoate ester of the metal compound possessing the four properties described in claim 1 being the organic compound, and the method for continuously carrying out all six steps described in claim 1 is a method for continuously producing conductive yarn in which an aggregate of metal nanoparticles, continuously bonded by friction welding, is formed on the internal voids and surface irregularities and the surface of the yarn.

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