Temperature sensing core yarn and preparation method and application thereof

Abstract

The application discloses a temperature sensing core elastic yarn and a preparation method and application thereof, and belongs to the technical field of functional textiles, and comprises elastic filament fibers, a plurality of signal transmission wires are wrapped around the periphery of the elastic filament fibers, a plurality of thermistor chips are electrically connected to the signal transmission wires, the plurality of thermistor chips are connected in series, a packaging structure is arranged on the periphery of the thermistor chips, and a protective fiber net is arranged on the outer side of the packaging structure; the temperature sensing core elastic yarn has the advantages of high sensitivity, miniaturization, local distribution temperature synchronous measurement, comfort and the like, the conductive elastic wrapped yarn formed by wrapping the plurality of signal transmission wires around the elastic filament fibers effectively solves the problems of poor strain resistance and washing resistance and large bending rigidity of the signal transmission line of the existing temperature sensing yarn, and overcomes the technical difficulty of complex signal transmission wiring in multi-point temperature synchronous detection.

Description

Technical Field

[0001] This invention belongs to the field of functional textile technology, specifically relating to a lumped temperature sensing core elastic yarn for continuous monitoring of multi-point local temperature of the human body in daily life and its preparation method. Background Technology

[0002] Skin temperature is an important physiological and pathological indicator. Continuous skin temperature monitoring can not only reflect a wealth of high-level user states, such as cognitive load, stress level, and emotional state, but also diagnose and predict diseases, such as early monitoring of foot ulcers and monitoring of the early healing status of wounds.

[0003] Existing methods for human body temperature monitoring include non-contact skin temperature measurement and contact skin temperature measurement. Non-contact skin temperature measurement uses mercury thermometers or infrared thermometers for body temperature monitoring. The limitations of this method are that it cannot measure body temperature during movement, and mercury thermometers have long measurement times and mercury leakage during use can easily cause environmental problems. Contact skin temperature measurement uses thermistors or thermocouples for body temperature monitoring. These temperature sensors are mostly not manufactured on textile substrates, and as temperature measurement systems that come into direct contact with injured skin, they offer poor comfort. Therefore, flexible temperature sensors based on textile substrates are receiving increasing attention.

[0004] With the continuous development of science and technology, flexible and biocompatible temperature sensors have been manufactured. However, most of them are large in size and cannot achieve localized multi-point measurements. Localized multi-point measurements are of great significance for monitoring the formation of foot ulcers in diabetic patients and pressure ulcers caused by prolonged bed rest, as well as for wound care, because temperature differences at multiple points in the wound area are an important signal of wound infection.

[0005] Chinese patent CN114532997A discloses a flexible temperature sensor including a microstructure and its preparation method. It develops a flexible temperature sensor containing a conical microstructure. Although the flexible temperature sensor is small in size, the microstructure needs to be inserted into the skin to achieve accurate temperature measurement during the measurement process. It is an invasive measurement and therefore not suitable for injured areas or daily skin temperature measurement.

[0006] Chinese patent CN112781741A discloses a high-sensitivity negative temperature coefficient flexible sensor and temperature measurement method for the body temperature range. The sensor integrates zinc oxide material with equally spaced electrodes onto a flexible membrane substrate (polyethylene, polypropylene, etc.) to form a temperature sensor. The flexible membrane has poor elasticity, air and moisture permeability, and cannot withstand harsh washing conditions.

[0007] US Patent No. US10301751 B2 discloses an electronic functional yarn, which includes multiple carrier fibers for mounting electronic components, conductive metal wires extending along the yarn axis, filling fibers surrounding the core layer, and a sheath layer surrounding the filling fibers. Because the straightened metal wires lack elasticity, they are prone to breakage under tensile or bending forces, making them unwashable and unsuitable for use in textiles with large deformation applications such as elastic underwear. Furthermore, the straightened conductive metal wires connecting the two poles of each electronic component are distributed along the yarn axis on both sides of the electronic component, which is not conducive to centralized wiring and connection to an external signal acquisition system when integrating them into smart textiles.

[0008] In summary, existing temperature sensing technologies have several limitations when it comes to continuous, long-term monitoring of body surface temperature based on clothing. These limitations include unsuitability for simultaneous monitoring of multiple localized temperatures, low concealment and comfort, and weak resistance to mechanical tensile and bending strains. Consequently, their application scenarios are limited, and they fail to meet the requirements for continuous, imperceptible monitoring of the body surface temperature distribution during daily activities. Summary of the Invention

[0009] The purpose of this invention is to provide a temperature sensing core elastic yarn, its preparation method and application, so as to solve the technical problems of existing temperature sensors being large in size and inelastic, which cannot meet the requirements of daily continuous dynamic body temperature monitoring and local multi-point synchronous real-time temperature monitoring.

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] A temperature sensing core elastic yarn includes elastic filament fibers, with multiple signal transmission wires wrapped around the periphery of the elastic filament fibers. Several thermistor chips are electrically connected to the signal transmission wires and are connected in series. The thermistor chips are encapsulated in a cylindrical encapsulation structure around their periphery, and a protective fiber mesh is wrapped around the outside of the encapsulation structure.

[0012] Furthermore, the elastic filament fiber is a low-denier rubber elastic fiber or a polyurethane elastic fiber, both of which have high elasticity and excellent tensile recovery rate.

[0013] Furthermore, the signal transmission conductor is a conductive metal wire enameled wire with a diameter not exceeding 0.07 mm. Since conductive metal wire enameled wire is easily brittle when bent or twisted at small radii of curvature, and the minimum radius of curvature required to prevent surface cracking is directly proportional to the fiber diameter and inversely proportional to the fiber's elongation at break, a conductive metal wire enameled wire with a diameter not exceeding 0.07 mm is selected. Preferably, the conductive metal wire enameled wire is made of a material with both low line resistance and low temperature coefficient of resistance, as the influence of low line resistance and low temperature coefficient of resistance on the elastic yarn of the temperature sensing core is negligible.

[0014] Furthermore, the thermistor chip is a sub-millimeter-sized negative temperature coefficient surface-mount thermistor; specifically, the thermistor chip selected in this invention is a 10kΩ 0402 negative temperature coefficient surface-mount thermistor (1mm long, 0.5mm wide, and 0.5mm high), which has the advantage of small size and can realize single-point body surface temperature measurement; when multiple thermistor chips are connected in series, they form a beaded distribution, which can meet the requirements of multi-point body surface temperature measurement within a millimeter range; preferably, even smaller and higher-performance surface-mount thermistors can be selected, all of which are within the protection scope of this invention.

[0015] Furthermore, the serial connection configuration involves electrically connecting the negative terminals of several thermistor chips to the same signal transmission line, and electrically connecting the positive terminals of several thermistor chips to a signal transmission line, forming a beaded lumped structure. This structure not only efficiently collects the temperature response data of each thermistor chip, but also reduces the amount of signal transmission lines used, thereby maintaining the softness of the elastic yarn of the temperature sensing core.

[0016] Furthermore, the diameter of the encapsulation structure does not exceed 1 mm and the length is less than 1.5 mm; a smaller thermistor chip can be selected, thereby further reducing the size of the encapsulation structure; the elastic encapsulation material used in the encapsulation structure is UV-curable polyurethane acrylate (PUA).

[0017] Furthermore, the protective fiber mesh is composed of several wear-resistant and thermally conductive insulating fibers, preferably nylon fibers. Because nylon has a high thermal conductivity and the pores formed by weaving and knitting facilitate heat transfer, the outer protective sleeve has a relatively small impact on the response time of the temperature sensing core elastic yarn.

[0018] A method for preparing a temperature-sensing core elastic yarn includes the following steps:

[0019] Step S1: The elastic filament fiber and the signal transmission wire are respectively introduced into the feed port of the wrapping machine. The signal transmission wire is spirally wrapped onto the elastic filament fiber by the wrapping machine to form a conductive elastic wrapping yarn; the pitch of the spiral is 2-4 times the diameter of the metal wire.

[0020] Step S2: Remove the paint from the ends of the signal transmission wires in the conductive elastic wrapping yarn, then apply an appropriate amount of low-temperature solder paste to the ends of the signal transmission wires after the paint has been removed, and weld and fix multiple signal transmission wires to several thermistor chips using a hot press welding device to obtain temperature-sensitive elastic wrapping yarn.

[0021] Step S3: Place the temperature-sensitive elastic wrapping yarn with the thermistor chip welded to it into the packaging mold. The packaging mold is a hollow cylinder with a diameter of 2mm and a length of 4mm. Then, fill the packaging mold with elastic packaging material. After curing, a packaging structure is formed, resulting in the packaged temperature-sensitive elastic wrapping yarn. The packaging structure places the welding point between the signal transmission wire and the thermistor chip, as well as the thermistor chip itself, inside as the temperature sensing area.

[0022] Step S4: Multiple insulating fibers are woven or wrapped around the encapsulated temperature-sensing elastic wrapping yarn to form a protective fiber mesh, thus obtaining the temperature-sensing core elastic yarn.

[0023] Furthermore, the temperature of the hot pressing equipment is set to 170°C, and the hot pressing time is 10 seconds.

[0024] An application of a temperature-sensing core elastic yarn in human body temperature monitoring fabrics, specifically a human body temperature monitoring wristband.

[0025] The beneficial effects of this invention are:

[0026] The temperature sensing core yarn produced by this invention has an elastic elongation ratio of not less than 50% and a maximum diameter of less than 1.1 mm. It possesses advantages such as high sensitivity, miniaturization, simultaneous measurement of locally distributed temperature, and high comfort. The conductive elastic wrapping yarn, formed by multiple signal transmission wires wrapped around elastic filament fibers, effectively solves the problems of poor strain resistance, washability, and high bending rigidity of existing temperature sensing yarns' signal transmission lines. It also overcomes the technical challenge of complex signal transmission wiring in multi-point temperature synchronous detection. Specific advantages are as follows:

[0027] 1. The temperature sensing core elastic yarn prepared by this invention has a small single temperature sensing area, which can realize body temperature measurement in areas with a precision down to millimeters; it can also integrate multiple thermistor chips within a length of a few millimeters to realize multi-point distributed temperature monitoring at the corresponding scale, and realize simultaneous measurement of multiple temperatures within sub-centimeter range on the body surface; it has high sensitivity when used for human body temperature monitoring, with a temperature threshold as low as 0.5℃ and has millisecond-level fast response characteristics.

[0028] 2. The temperature sensing core elastic yarn obtained by this invention has a small diameter, which is comparable to most clothing seams. It is well concealed, imperceptible when worn, and can be processed into fabric using traditional weaving methods, combining flexibility and comfort.

[0029] 3. The temperature sensing core elastic yarn prepared by this invention has excellent elasticity and can resist mechanical stress during daily wear and washing. The inventors washed it 15 times using an industrial machine washing program and no functional failure occurred. The packaging structure can effectively protect the internal thermistor chip from chemical corrosion during the washing process, and has practical application value. Attached Figure Description

[0030] The invention will now be further described with reference to the accompanying drawings.

[0031] Figure 1 This is a schematic diagram of the structure of the temperature sensing core elastic yarn of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the temperature-sensitive elastic wrapping yarn after encapsulation according to the present invention;

[0033] Figure 3 This is a schematic diagram of the packaging structure of the present invention;

[0034] Figure 4 This is a graph showing the change in resistance over time as temperature changes occur with the human body temperature monitoring wristband prepared in Example 3.

[0035] Figure 5 This is a standard curve of temperature versus resistance for the human body temperature monitoring wristband prepared in Example 3 when monitoring temperature changes.

[0036] In the diagram: 1. Elastic filament fiber; 2. Signal transmission wire; 3. Thermistor chip; 4. Packaging structure; 5. Protective fiber mesh. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] This embodiment provides a single-point temperature sensing core elastic yarn, including an elastic filament fiber 1, with two signal transmission wires 2 wrapped around the periphery of the elastic filament fiber 1, and the ends of the two signal transmission wires 2 electrically connected to a thermistor chip 3. The thermistor chip 3 is encapsulated with a cylindrical encapsulation structure 4 with a diameter of 1 mm and a length of 1.4 mm around its periphery, and a protective fiber mesh 5 is covered on the outside of the encapsulation structure 4. The protective fiber mesh 5 is composed of 12 insulating fibers.

[0040] Among them, the elastic filament fiber 1 is 1120D spandex, the signal transmission wire 2 is copper wire enameled wire with a diameter of 0.07mm, the thermistor chip 3 is 0402 negative temperature coefficient chip thermistor, and the insulating fiber is nylon fiber.

[0041] This type of temperature-sensing core elastic yarn is prepared by the following method:

[0042] Step S1: Introduce one 1120D spandex and two copper enameled wires into the feed inlet of the wrapping machine. The wrapping machine spirally wraps the two copper enameled wires onto the spandex. The pitch of the spiral is twice the diameter of the metal wire, forming a conductive elastic wrapping yarn.

[0043] Step S2: Remove the enamel from the ends of the two copper wire enameled wires in the conductive elastic wrapping yarn, then apply an appropriate amount of low-temperature solder paste to the ends of the copper wire enameled wires after removing the enamel. Then, transfer a 0402 negative temperature coefficient chip thermistor into a hot press welding device. At a temperature of 170°C, hot press the two copper wire enameled wires onto the positive and negative poles of the 0402 negative temperature coefficient chip thermistor for 10 seconds to obtain the temperature-sensitive elastic wrapping yarn.

[0044] Step S3: Place the temperature-sensitive elastic wrapping yarn with the thermistor welded on it into a hollow cylindrical encapsulation mold with a diameter of 2mm and a length of 4mm. Then fill the encapsulation mold with UV-curable polyurethane acrylate. After UV curing, demold to form encapsulation structure 4, and obtain the encapsulated temperature-sensitive elastic wrapping yarn.

[0045] Step S4: 12 nylon fibers (100D / 34F×2) are woven into the outer layer of the encapsulated temperature-sensing elastic wrapping yarn using a high-speed braiding machine to form a protective fiber net 5, thus obtaining the temperature-sensing core elastic yarn.

[0046] Example 2

[0047] This embodiment provides a multi-point temperature sensing core elastic yarn, including an elastic filament fiber 1, with five signal transmission wires 2 wrapped around the periphery of the elastic filament fiber 1. Four evenly distributed thermistor chips 3 are disposed on the signal transmission wire 2. The negative terminals of the four thermistor chips 3 are electrically connected to the signal transmission wire 2, and the positive terminals of the four thermistor chips 3 are electrically connected to the ends of the other four signal transmission wires 2 respectively. The periphery of each of the four thermistor chips 3 is encapsulated with a cylindrical encapsulation structure 4 with a diameter of 1 mm and a length of 1.4 mm. The outer side of the encapsulation structure 4 is covered with a protective fiber mesh 5, which is composed of 12 insulating fibers.

[0048] Among them, the elastic filament fiber 1 is 1120D spandex, the signal transmission wire 2 is copper wire enameled wire with a diameter of 0.07mm, the thermistor chip 3 is 0402 negative temperature coefficient chip thermistor, and the insulating fiber is nylon fiber.

[0049] This type of temperature-sensing core elastic yarn is prepared by the following method:

[0050] Step S1: Introduce one 1120D spandex and five copper enameled wires into the feed inlet of the wrapping machine. The wrapping machine spirally wraps the five copper enameled wires onto the spandex. The pitch of the spiral is four times the diameter of the metal wire, forming a conductive elastic wrapping yarn.

[0051] Step S2: Remove the enamel from the ends of the five copper wires in the conductive elastic wrapping yarn, and also remove the enamel from the position of the thermistor chip 3 on one of the copper wires. Then apply an appropriate amount of low-temperature solder paste to the copper wires after removing the enamel. Then transfer the 0402 negative temperature coefficient chip thermistors one by one into the hot press welding equipment. At a temperature of 170°C, first heat press weld the negative terminals of four 0402 negative temperature coefficient chip thermistors to one copper wire for 10 seconds to fix them. Then heat press weld the ends of the other four copper wires to the positive terminals of the four 0402 negative temperature coefficient chip thermistors respectively to fix them, thus obtaining the temperature-sensitive elastic wrapping yarn.

[0052] Step S3: Place the four points of the temperature-sensitive elastic wrapping yarn with thermistors welded on them into a hollow cylindrical encapsulation mold with a diameter of 2mm and a length of 4mm. Then fill the encapsulation mold with UV-curable polyurethane acrylate. After UV curing, demold to form encapsulation structure 4, and obtain the encapsulated temperature-sensitive elastic wrapping yarn.

[0053] Step S4: 12 nylon fibers (100D / 34F×2) are woven into the outer layer of the encapsulated temperature-sensing elastic wrapping yarn using a high-speed braiding machine to form a protective fiber net 5, thus obtaining the temperature-sensing core elastic yarn.

[0054] Example 3

[0055] This embodiment provides a human body temperature monitoring wristband, which is manufactured by the following method:

[0056] The temperature sensing core elastic yarn prepared in Example 1 is embedded into the wristband by embroidery. The temperature sensing core elastic yarn is placed in the center of the wristband to obtain a human body temperature monitoring wristband. The temperature sensing core elastic yarn senses the temperature change of the human body, and the change in resistance value reflects the temperature change of the human body.

[0057] The human body temperature monitoring wristband prepared in Example 3 was electrically connected to the KEYS I GHT monitor to monitor the resistance change of the thermistor caused by the change in wrist temperature in real time. The resistance value was read every 1ms. The skin of the test area was heated using a heat gun. The test results are as follows. Figure 4 As shown, the human body temperature monitoring wristband has high monitoring sensitivity, a temperature threshold as low as 0.5℃, and a millisecond-level fast response characteristic.

[0058] The human body temperature monitoring wristband prepared in Example 3 was placed in a constant temperature platform. The temperature range of the constant temperature platform was set between 28-43℃, and the temperature was maintained for 5 minutes for every 1℃ increase. Then, the average value of the resistance value monitored during this time period was taken, and its standard deviation was calculated. The results are as follows. Figure 5 As shown.

[0059] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A temperature-sensing core elastic yarn, characterized in that, The device includes an elastic filament fiber (1), on which a plurality of signal transmission wires (2) are wrapped around its periphery. A plurality of thermistor chips (3) are electrically connected to the signal transmission wires (2). The plurality of thermistor chips (3) are connected in series. A packaging structure (4) is provided on the periphery of the thermistor chip (3). A protective fiber mesh (5) is provided on the outside of the packaging structure (4). The elastic filament fiber (1) is a low denier rubber elastic fiber or a polyurethane elastic fiber; The signal transmission wire (2) is a conductive metal wire enameled wire with a diameter of no more than 0.07 mm; The thermistor chip (3) is a sub-millimeter size negative temperature coefficient surface mount thermistor. The series connection configuration is that the negative terminals of several thermistor chips (3) are electrically connected to the same signal transmission line (2), and the positive terminals of several thermistor chips (3) are electrically connected to a signal transmission line (2). The diameter of the encapsulation structure (4) is no more than 1 mm and the length is less than 1.5 mm; the elastic encapsulation material used in the encapsulation structure (4) is UV-curable polyurethane acrylate. The protective fiber mesh (5) is composed of several wear-resistant and thermally conductive insulating fibers.

2. The method for preparing a temperature-sensing core elastic yarn according to claim 1, characterized in that, Includes the following steps: Step S1: The elastic filament fiber (1) and the signal transmission wire (2) are respectively introduced into the wrapping machine. The signal transmission wire (2) is spirally wrapped onto the elastic filament fiber (1) by the wrapping machine to obtain conductive elastic wrapped yarn; the pitch of the spiral is 2-4 times the diameter of the signal transmission wire (2); Step S2: Remove the paint from the end of the signal transmission wire (2) in the conductive elastic wrapping yarn, then apply an appropriate amount of low temperature solder paste to the end of the signal transmission wire (2) after the paint has been removed, and weld multiple signal transmission wires (2) to several thermistor chips (3) by hot pressing welding equipment to obtain temperature-sensitive elastic wrapping yarn. Step S3: Place the temperature-sensitive elastic wrapping yarn into the encapsulation mold, then fill the encapsulation mold with elastic encapsulation material, and after curing, form an encapsulation structure (4) to obtain the encapsulated temperature-sensitive elastic wrapping yarn; Step S4: Multiple insulating fibers are woven or wrapped around the encapsulated temperature-sensing elastic wrapping yarn to form a protective fiber mesh (5), thus obtaining the temperature-sensing core elastic yarn.

3. The method for preparing a temperature-sensing core elastic yarn according to claim 2, characterized in that, The temperature of the hot-press welding equipment is set to 170℃, and the hot-pressing time is 10s.

4. The application of the temperature-sensing core elastic yarn according to claim 1 in human body temperature monitoring fabrics.

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