A flexible pure metal spun yarn and a method of manufacturing the same

Abstract

The application provides a flexible pure metal spun yarn and a preparation method thereof. A water-soluble polyvinyl alcohol fiber is creatively introduced in a spinning process to solve the technical problem of high breakage rate and discontinuous production caused by the high rigidity and difficult drafting of pure metal fibers in the processes of drawing, roving, spinning and bobbin winding. The bobbin yarn obtained through the above processes is placed in a bobbin cleaning and drying all-in-one machine, the water-soluble polyvinyl alcohol fiber is removed through the processes of cleaning, dehydration and drying, and the pure metal spun yarn is obtained after re-twisting, which makes up for the defects of the existing pure metal yarn structure, such as compact structure, hard texture and poor flexibility. The preparation method does not need to modify the equipment, and the batch production of the flexible pure metal yarn can be realized by using the conventional cotton spinning equipment. The developed flexible pure metal fabric can be used for the solidification and transmission of hot workpieces (glass and display screen), the high-temperature purification and filtration of pollutants in petrochemical industry, metallurgy and other industries, and the development of electromagnetic shielding products.

Description

Technical Field

[0001] This invention belongs to the technical field of functional textile preparation methods, and relates to a method for preparing flexible pure metal staple fiber yarn. Background Technology

[0002] Metal fibers refer to fibrous materials with a high metal content and continuous distribution of metal material, with transverse dimensions ranging from 1 to 100 micrometers. Based on the metal content, metal fibers are classified into metal composite fibers (such as aluminum / polyester composite fibers), metallized fibers (silver-plated fibers, copper-plated fibers), and pure metal fibers (stainless steel fibers, nickel fibers, copper microfibers, etc.). Based on different production processes, pure metal fibers can be divided into melt-drawn metal fibers, drawn metal fibers, and cut metal fibers. Pure metal fibers have a metallic luster and a bright surface. They retain the advantages of metals, such as electrical conductivity, thermal conductivity, corrosion resistance, high temperature resistance (stainless steel 600–700℃, iron-chromium-aluminum 800–900℃), wear resistance, and high strength, while also acquiring properties similar to textile fibers, such as softness and high specific surface area. They possess eight major functions: electromagnetic wave protection, antistatic properties, electrical conductivity, high temperature resistance, cut resistance, friction resistance, filtration, and sound absorption / insulation.

[0003] Textiles incorporating metal fibers possess a variety of special functions and are mainly divided into two categories: metal fiber blended textiles and pure metal fiber textiles. Currently, there is extensive research on metal fiber blended textiles, but less research on pure metal fiber products. Pure metal fiber products mainly include metal fiber sintered felt, metal fiber composite nonwoven fabrics, and pure metal fiber fabrics. Dust sealing bags made from pure metal fiber fabrics are used in high-temperature petrochemical and chemical industries, high-temperature coal gas in the metallurgical industry, the glass industry, and for purifying vehicle exhaust. Heat-insulating curtains and heat-resistant cushioning pads made from pure metal fiber fabrics can be used in conveyor belts for hot workpieces (glass, displays), etc. Compared with other materials, pure metal fiber fabrics have better resistance to oxidation, high temperature and pressure, and sulfuric acid corrosion. They can operate at 600–800℃ for over 6000 hours while maintaining good thermal stability and the ability to be repeatedly cleaned and reused, providing a scientific, reliable, economical, and environmentally friendly low-carbon foundation for industrial development. As the market demand for pure metal fiber fabrics continues to grow, the demand for pure metal fiber yarns will also become increasingly prominent.

[0004] Metal fibers suitable for spinning are mainly produced using the bundle drawing method. The main fiber types include stainless steel fibers, copper fibers, and nickel fibers. Among these, stainless steel fibers are the most widely used. Stainless steel fibers are typically made of 316L or 304 stainless steel, with a single fiber diameter generally ranging from 6 to 12 μm. Their cross-section is an irregular polygon with longitudinal grooves and stripes, and the surface is uneven. In actual production, many problems restrict its development and utilization. For example, when produced as long filament bundles, they cannot be directly used for spinning. They need to be drawn and cut into short fiber strips of appropriate length to be suitable for spinning. Compared with commonly used natural and chemical fibers, pure metal fibers, after being drawn and cut, exhibit significant differences in geometric characteristics such as fineness and length, as well as physical and mechanical properties such as density, breaking strength, breaking elongation, and friction performance. They show obvious characteristics such as high specific gravity, low strength, and low elasticity. Only when blended with other fibers (such as cotton, viscose, and aramid) in a certain proportion can they meet the basic requirements for spinning and possess a certain degree of spinnability. Due to the unique characteristics of metal fiber raw materials (significantly different from conventional fibers in terms of physical and mechanical properties such as density, elongation, flexural strength, and surface friction characteristics), achieving the spinning of pure metal staple fiber yarn is difficult if the technical solution and spinning process settings are not reasonable. The main technical challenges are as follows:

[0005] First, the unique characteristics of metal fibers lead to a high yarn breakage rate and poor production continuity. Metal fibers have high rigidity, low elongation, small elastic bending, and a high dynamic friction coefficient, resulting in strong inter-fiber cohesion during spinning, making drafting difficult and even causing problems such as "unable to separate" and "hard ends." This results in uneven yarn, low yarn strength, a high breakage rate, and poor continuous production. Currently, the highest spindle speed is only 5000 rpm, leading to low production efficiency. Furthermore, metal fibers are much stiffer than ordinary fibers, making them extremely prone to twisting after yarn formation. Even slight relaxation of the yarn will immediately cause it to twist into small braids, making unwinding processes such as winding difficult and hindering normal production.

[0006] Secondly, pure metal yarns have a dense structure and a stiff, inflexible texture. The higher the yarn count, the finer the yarn. Since metal staple fibers are made of pure metal, their specific gravity is 5 to 8 times that of ordinary textile staple fibers. Under the same yarn count, the number of fibers in the cross-section of a pure metal fiber yarn is only 1 / 8 to 1 / 5 of that of conventional cotton yarn. Given that the single fiber strength of pure metal fibers is comparable to that of cotton fibers, high-count pure metal staple fibers are extremely difficult to process. Current technology can only spin pure metal yarns with a linear density range of 74 tex to 120 tex (approximately 5 to 8 counts), resulting in a dense structure and a stiff, inflexible texture. The resulting shortcomings are manifested at the microscopic level, because pure metal fibers... The dense arrangement of fabrics with small gaps between yarns or metal fibers makes it easy for dust and other particles to clog the filter channels, affecting the filtration and purification effect of dust sealing bags. From a macroscopic perspective, due to the high rigidity and poor elasticity of metal fibers and the poor softness of yarns, the fabrics are heavy. When made into heat insulation curtains, conveyor belts, or heat-resistant cushioning pads, the hard fabric surface has a poor cushioning effect when in contact with incompletely cured hot workpieces (glass, displays), which can easily cause some damage to the outer surface of the incompletely cured hot workpieces and affect the surface smoothness of the hot workpieces. It can be seen that the poor flexibility of yarns seriously limits and affects their application value and applicability.

[0007] In the existing technology, the only research on spinning pure metal fiber staple yarn currently available is Cao Hongmei's paper "Discussion on the Spinning Process of Pure Stainless Steel Fiber." This paper uses a small-scale spinning machine to spin pure metal fiber staple yarn, relying on the convenience of stopping the machine at any time to handle yarn breaks to ensure continuous yarn production. However, the linear density of the spun yarn is limited to 74 tex to 120 tex, making it unsuitable for spinning high-count yarns. Therefore, the technical solution in this paper is only suitable for small-batch production, has poor production continuity, and does not address the aforementioned technical shortcomings from a process technology perspective, hindering large-scale industrial application and promotion.

[0008] Invention CN103225153B discloses a method for preparing metal filament strands. The preparation process includes initial composite wire preparation, diameter reduction drawing to intermediate composite wire, twisting the intermediate composite wire, setting and drawing to finished composite wire, and electrochemical separation. This invention provides a technical means for processing metal filaments into twisted yarns. The metal filament yarn has a smooth and dense appearance, a smooth and stiff fabric surface, poor flexibility, a difficult setting process, and can only hold a small amount of static air inside the yarn, resulting in poor high-temperature resistance and cushioning performance.

[0009] CN107513792A discloses a metal fiber cloth, its preparation method, and its application. The areal density of the metal fiber cloth is 150-1500 g / m², and the diameter of the metal fibers is 2-50 micrometers. During molding, applying the metal fiber cloth to one or both sides of the glass can significantly improve the yield rate of curved glass molding, increasing it from 60% to over 90%. This invention has lower precision requirements for the mold; calculations show that the finished product yield of the mold is increased by approximately 14%. This invention can extend the service life of the mold by more than 50%. In summary, after using this invention, the cost of the mold is significantly reduced, the polishing of curved glass is easier, the product yield is significantly improved, and the cost is significantly reduced.

[0010] CN104026784A discloses a magnetically conductive fiber blended fabric. This fabric is woven from a blend of four types of fibers: stainless steel metal fibers, conductive and magnetically conductive polyaniline-coated short carbon fibers, conductive glass fibers, and conductive polyvinyl alcohol fibers. The weight percentages of each fiber component in the fabric are as follows: stainless steel metal fibers 13%–17%, conductive and magnetically conductive polyaniline-coated short carbon fibers 28%–32%, conductive glass fibers 30%–34%, and conductive polyvinyl alcohol fibers 17%–29%. This fabric, woven from these four fibers, exhibits excellent electrical and magnetic conductivity, providing good electromagnetic shielding.

[0011] CN106675738A discloses a method for preparing a metal wire drawing lubricant, belonging to the field of lubricant preparation technology. This invention uses methyl ricinoleate as a raw material to obtain a lubricating oil base oil. Then, molybdenum disulfide crystals are exfoliated using an ultrasonic-assisted exfoliation method to obtain a graphene-like structure of molybdenum disulfide. This graphene-like structure is then combined with a carbon nanotube dispersion, allowing carbon nanotubes to be incorporated into the spaces between the graphene-like structure of the molybdenum disulfide, resulting in a dispersion with high stability, high heat dissipation, and good dispersibility. Finally, the lubricating oil base oil, polyvinyl alcohol, deionized water, etc., are stirred and mixed with the carbon-doped graphene-like structure of molybdenum disulfide dispersion to obtain the metal wire drawing lubricant. This invention utilizes the prepared graphene-like structure of molybdenum disulfide to form a low shear stress film on the surface of the friction pair, thereby reducing the coefficient of friction and providing a filling and repairing effect on the friction surface. Furthermore, it is less prone to metal wire breakage and unpleasant odors during use, posing no harm to the environment or human body, and has broad application prospects.

[0012] CN104055255A discloses a metal fiber blended fabric, which is woven from four types of fibers: stainless steel short fibers, carbon steel short fibers, nylon fibers, and polyvinyl alcohol fibers. The weight percentages of each fiber component in the fabric are as follows: stainless steel short fibers account for 17%–21%, carbon steel short fibers account for 19%–23%, nylon fibers account for 34%–38%, and polyvinyl alcohol fibers account for 18%–30%. This fabric, woven from these four fibers, exhibits good abrasion resistance, elasticity, electrical conductivity, magnetic permeability, shielding properties, thermal conductivity, and chemical resistance.

[0013] Existing technical solutions have not solved the problems of high yarn breakage rate, poor production continuity, and the dense structure, stiff texture, and poor flexibility of existing pure metal yarns due to the special properties of metal fibers during the spinning process.

[0014] Therefore, how to better realize the spinning of flexible pure metal staple fiber yarns and ultimately form a stable process technology solution to spin various flexible pure metal fiber staple fiber blended yarns that meet the requirements, so as to meet the urgent needs of downstream industries such as petroleum, chemical, military, aviation, communications, power, environmental protection, and automobiles, is a technical problem that urgently needs to be solved. Summary of the Invention

[0015] To address the shortcomings of the prior art, the present invention aims to provide a flexible pure metal staple fiber yarn and a method for preparing the yarn.

[0016] One aspect of the present invention provides a method for preparing flexible pure metal staple fiber yarn, comprising the following steps:

[0017] Step 1, Preparation of water-soluble polyvinyl alcohol fiber sliver: After unpacking the water-soluble polyvinyl alcohol fiber, it is allowed to stand and equilibrate for 24 hours. Then, it is fed into the blending and opening machine through the condenser. After being opened and impurities removed by the blending and opening machine, the water-soluble polyvinyl alcohol fiber is transported to the carding machine through the cotton conveying pipe. The carding machine further opens, combs and removes impurities from the water-soluble polyvinyl alcohol fiber, so that the curled fiber clumps are combed into basically straight single fibers. After being drawn and assembled, water-soluble polyvinyl alcohol fiber sliver is formed.

[0018] Step 2, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber mixed sliver: The single water-soluble polyvinyl alcohol fiber sliver prepared in Step 1 and the metal fiber sliver are mixed in different proportions and then combined in three stages using a drawing frame to finally form a mixed sliver of polyvinyl alcohol fiber and metal fiber.

[0019] Step 3, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended yarn: The water-soluble polyvinyl alcohol fiber and metal fiber blended sliver prepared in step 2 are passed through a roving frame, a spinning frame and a loose winding machine to form water-soluble polyvinyl alcohol fiber / metal fiber blended yarn.

[0020] Step 4, Preparation of flexible pure metal staple fiber single yarn or ply yarn: Place multiple cones of water-soluble polyvinyl alcohol fiber and metal fiber blend prepared in Step 3 into a cone yarn cleaning and drying integrated machine. Set different cleaning temperatures, cleaning times, and washing liquid circulation times to completely remove the water-soluble polyvinyl alcohol fiber from the blended cones. Then, dehydrate the yarn and finally dry it at a certain drying temperature to obtain a relatively loose pure metal fiber staple fiber single yarn I. Then, use a twisting machine to twist the single yarn I a second time to form a pure metal fiber staple fiber single yarn with a stable, fluffy and soft yarn structure.

[0021] In one embodiment, in step 4, the short fiber single yarn can be further plyed, twisted, and combined to obtain a flexible pure metal fiber short fiber ply yarn.

[0022] In one embodiment, the dissolution temperature of the water-soluble polyvinyl alcohol fiber in step 1 is 20-60°C, and the average length of the water-soluble polyvinyl alcohol fiber is 38-51 mm.

[0023] In one embodiment, the speed range of the carding machine licker-in roller in step 1 is 660-720 rpm, the cylinder speed range is 280-320 rpm, the flats speed range is 80-100 rpm, and the sliver weight is between 12-15 g / 5m.

[0024] In one embodiment, the proportion of water-soluble polyvinyl alcohol fiber slivers in step 2 is 5% to 10%.

[0025] In one embodiment, the metal fiber cutting strips mentioned in step 2 include stainless steel metal fiber cutting strips, copper microfiber cutting strips, and silver microfiber cutting strips.

[0026] In one embodiment, the diameter of the metal fibers in the metal fiber slivers described in step 2 is 6–10 μm, and the average length of the pure metal fibers is 38–51 mm.

[0027] In one embodiment, the drawing process in step 2 adopts a three-stage drawing process. In the first stage, one water-soluble polyvinyl alcohol fiber sliver is fed in simultaneously with 7 to 11 metal fiber slivers (i.e., 8 to 11 slivers are fed in). In the second and third stages, 8 blended slivers are fed in to ensure the uniformity of the two different fibers. The final drawing weight is controlled at 25 to 35 g / 5m, the bell mouth diameter is 3.6 mm, and the sliver output speed is 130 to 150 m / min.

[0028] In one embodiment, the process parameters for the roving process in step 3 are: roving weight 10-15g / 10m, twist coefficient 70-90, spindle speed 500-800 rpm, and back zone draft ratio 1.3.

[0029] In one embodiment, the process parameters for the spinning process in step 3 are: roller center distance 54mm×68mm, back zone draft ratio 1.2~1.5, nip spacing 4.5mm, twist coefficient 280~350, and spindle speed 7000~9000 rpm.

[0030] In one embodiment, the bulk density of the yarn formed in the winding process described in step 3 is controlled at 0.35 to 0.50 g / cm³.

[0031] In one embodiment, the cleaning temperature in step 4 is 40-80°C, the cleaning time is 15-20 minutes, the forward and reverse circulation time of the washing liquid is 10-15 minutes, the dehydration time is 2-5 minutes, and the yarn is dried at 100-120°C.

[0032] In one embodiment, the linear density of the flexible pure metal fiber short yarn in step 4 is 24.6 to 59.0 tex, the twist is 450 to 580 twists / m, and the breaking strength is 10.0 to 15.0 cN / tex.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] The method for preparing flexible pure metal staple fiber yarn described in this invention uses water-soluble polyvinyl alcohol fibers with a dissolution temperature of 20-60°C. The low dissolution temperature helps to completely remove the water-soluble polyvinyl alcohol fibers and also helps to reduce energy consumption.

[0035] In the spinning process of flexible pure metal yarn, this invention creatively introduces water-soluble polyvinyl alcohol fiber slivers and metal fiber slivers into the drawing process. This innovative approach significantly improves the elasticity of the pure metal fiber slivers, aiding in their drawing and preventing breakage during the drawing and roving processes. It also reduces the number of hooked pure metal fibers, increases their straightness, and avoids random unevenness caused by "drawing waves," thus laying a solid foundation for yarn evenness and ensuring production continuity and efficiency.

[0036] The method for preparing flexible pure metal staple fiber yarn of the present invention, in the spinning process, due to the excellent elasticity of water-soluble polyvinyl alcohol fiber (breaking elongation as high as 11.8%), solves the problem of severe wear of the spinning machine rollers caused by the high rigidity of pure metal fibers, improves the insufficient buffer difference of tension setting, and is conducive to further stretching of pure metal fibers, which significantly improves the strength of the twisted yarn, reduces the yarn breakage rate, and ensures smooth and efficient yarn spinning. It can increase the spindle speed from the existing 5000 rpm to 7000-9000 rpm, achieving a double improvement in spinning speed and production efficiency. It realizes the spinning of pure metal yarn without the need for equipment modification, and can be achieved by adjusting the process using conventional cotton spinning equipment.

[0037] In the winding process of the flexible pure metal staple fiber yarn preparation method of the present invention, since the yarn body contains water-soluble polyvinyl alcohol fiber, the problem of easy kinking of pure metal yarn is avoided, the difficulty of unwinding the yarn is reduced, and the yarn can be automatically spliced ​​using a conventional air splicer, which can form a yarn package that meets the needs of subsequent production and processing.

[0038] The water-soluble polyvinyl alcohol fiber used in this invention has a density of 1.26–1.30 g / cm³. 3 The density of pure metal fibers ranges from 7.98 to 8.92 g / cm³. 3 As can be seen, the density of pure metal fibers is 6 to 7 times that of water-soluble polyvinyl alcohol fibers. Therefore, in this invention, the mass ratio of water-soluble polyvinyl alcohol fibers is 5% to 10%. Under the premise of having little impact on the yarn linear density, the total number of fibers in the yarn cross section can be significantly increased, presenting a technical effect of "small addition, big effect". It can effectively broaden the processing range of pure metal short fiber yarn linear density, so that the linear density of spinnable pure metal yarn is reduced from 75 tex to 25 tex. This solves the shortcomings of existing pure metal yarns, such as dense structure, stiff texture, poor flexibility, and inability to spin high-count yarns.

[0039] The water-soluble polyvinyl alcohol fiber used in this invention has a low dissolution temperature (20-60℃) and can be completely dissolved in water under certain temperature and time conditions. The water-soluble polyvinyl alcohol fiber used in this invention is tasteless and non-toxic after dissolving in water, and the aqueous solution is colorless and transparent. It can be naturally biodegraded in a short time and does not pollute the environment.

[0040] The present invention prepares a yarn package containing a blend of water-soluble polyvinyl alcohol (PVA) fiber and metal fiber. Placed in a yarn washing and drying integrated machine, the PVA fiber undergoes washing, dehydration, and drying processes, resulting in complete removal of the PVA fiber. This achieves the separation of the PVA fiber from the pure metal fiber, yielding a loosely structured pure metal fiber short yarn I. This yarn I is then double-twisted using a twisting machine to form a stable, flexible pure metal fiber short yarn. This pure metal short yarn has a fluffy and soft structure with large fiber gaps. When made into pure metal fiber fabric, its physical and mechanical properties and filtration and purification effects are superior to existing metal felts. Furthermore, the loose structure of this pure metal short yarn contains abundant static air, resulting in excellent thermal insulation performance. Products developed using this yarn, such as high-temperature buffer pads and conveyor belts, exhibit soft and uniform texture, excellent high-temperature resistance, thermal insulation, and buffering performance, which is beneficial for the curing and conveying of hot workpieces (glass, displays).

[0041] In summary, the method for preparing flexible pure metal staple yarn described in this invention creatively introduces water-soluble polyvinyl alcohol (PVA) fibers, enhancing the elasticity of the mixed fiber sliver, facilitating fiber drafting and yarn unwinding, reducing breakage rate, and ensuring continuous production of pure metal staple yarn. The blended yarn cones are then placed in a yarn washing and drying integrated machine, where the water-soluble PVA fibers are completely removed through washing, dehydration, and drying processes, achieving separation of the water-soluble PVA fibers from the pure metal fibers. After two twisting processes, pure metal staple yarn can be prepared. This pure metal staple yarn has a fluffy and soft structure, large fiber porosity, and good heat insulation and cushioning properties.

[0042] As can be seen, by introducing water-soluble polyvinyl alcohol fiber, this invention creatively achieves the production of flexible pure metal yarn without modifying the equipment, using conventional cotton spinning equipment and through a technological solution. The produced yarn has excellent performance, a short process flow, high production efficiency, and is environmentally friendly, making it suitable for large-scale application and promotion. Attached Figure Description

[0043] Appendix Figure 1 This is the process flow of the method for preparing flexible pure metal staple fiber yarn of the present invention. Detailed Implementation

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0045] The process flow diagram of the method for preparing flexible pure metal staple fiber yarn provided by this invention is as follows: Figure 1As shown, the process includes step 1, preparation of water-soluble polyvinyl alcohol fiber sliver; step 2, preparation of sliver made by mixing water-soluble polyvinyl alcohol fiber and metal fiber; step 3, preparation of blended yarn of water-soluble polyvinyl alcohol fiber and metal fiber; and step 4, preparation of flexible pure metal staple fiber single yarn or ply yarn.

[0046] The following describes specific embodiments of the method for preparing flexible pure metal staple fiber yarn of the present invention.

[0047] Example 1:

[0048] A method for preparing flexible pure metal staple fiber yarn includes step 1, preparation of water-soluble polyvinyl alcohol (PVA) fiber sliver: After unpacking the water-soluble PVA fiber, it is allowed to stand and equilibrate for 24 hours. It is then fed into a blending and opening machine via a condenser. After being opened and impurity removed by the blending and opening machine, the water-soluble PVA fiber is conveyed to a carding machine via a cotton conveying pipe. The carding machine further opens, combs, and removes impurities from the water-soluble PVA fiber layer, causing the crimped fiber clumps to be combed into basically straight single fibers. These fibers are then drawn and aggregated to form a water-soluble PVA fiber sliver. The dissolution temperature of the water-soluble PVA fiber is 20℃, and the average length of the water-soluble PVA fiber is controlled to be 38 mm. The speed of the carding machine's licker-in roller is controlled at 660 rpm, the cylinder speed at 280 rpm, and the flats speed at 80 rpm.

[0049] Step 2, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended sliver: The single water-soluble polyvinyl alcohol fiber sliver prepared in Step 1 and the metal fiber sliver are mixed in different proportions using a drawing frame through three blending processes to finally form a blended polyvinyl alcohol fiber and metal fiber sliver. The water-soluble polyvinyl alcohol fiber sliver accounts for 5% of the total sliver. Stainless steel metal fiber slivers are selected for the metal fiber slivers. The diameter of the metal fibers in the metal fiber slivers is 10 μm, and the average length of the pure metal fibers is 38 mm. The drawing process uses three draws. In the first draw, one water-soluble polyvinyl alcohol fiber sliver and 11 metal fiber slivers are fed in simultaneously. In the second and third draws, eight blended slivers are fed in to ensure the uniformity of the two different fibers. The final draw weight is controlled at 26 g / 5 m, the bell diameter is 3.6 mm, and the sliver output speed is 130 m / min.

[0050] Step 3, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended yarn: The water-soluble polyvinyl alcohol fiber and metal fiber blended sliver prepared in Step 2 is sequentially passed through a roving frame, a spinning frame, and a loose winding machine to form water-soluble polyvinyl alcohol fiber / metal fiber blended yarn. The process parameters for the roving process are: roving weight 12g / 10m, twist coefficient 70, spindle speed 800 rpm, and back zone draft ratio 1.3; the process parameters for the spinning process are: roller center distance 54mm×68mm, back zone draft ratio 1.25, nip spacing 4.5mm, twist coefficient 280, and spindle speed 7000 rpm; the bulk density of the yarn formed in the winding process is controlled at 0.35g / cm³.

[0051] Step 4, Preparation of Flexible Pure Metal Short Fiber Yarn or Ply Yarn: Multiple cones of water-soluble polyvinyl alcohol fiber and metal fiber blend prepared in Step 3 are placed in a cone yarn cleaning and drying machine. Different cleaning temperatures, cleaning times, and washing liquid circulation times are set to completely remove the water-soluble polyvinyl alcohol fiber from the blended cones. Then, dehydration is performed, and finally, the yarn is dried at a specific drying temperature to obtain a relatively loosely structured pure metal fiber short fiber yarn I. Yarn I is then double-twisted using a twisting machine to form a stable, fluffy, and soft pure metal fiber short fiber yarn. The cleaning temperature is 40℃, the cleaning time is 20 minutes, the washing liquid circulation time is 10 minutes, the dehydration time is 3 minutes, and the cones are dried at 100℃. The linear density of the flexible pure metal fiber short fiber yarn is 59.0 tex, the twist is 450 twists / m, and the breaking strength is 10.0 cN / tex.

[0052] Depending on the specific circumstances, short fiber single yarns can also be plyed, twisted, and combined to obtain flexible pure metal fiber short fiber ply yarns with a linear density of 59.0 tex × 2.

[0053] Example 2:

[0054] A method for preparing flexible pure metal staple fiber yarn includes step 1, preparation of water-soluble polyvinyl alcohol (PVA) fiber sliver: After unpacking the water-soluble PVA fiber, it is allowed to stand and equilibrate for 24 hours. It is then fed into a blending and opening machine via a condenser. After being opened and impurity removed by the blending and opening machine, the water-soluble PVA fiber is conveyed to a carding machine via a cotton conveying pipe. The carding machine further opens, combs, and removes impurities from the water-soluble PVA fiber layer, causing the crimped fiber clumps to be combed into basically straight single fibers. These fibers are then drawn and aggregated to form a water-soluble PVA fiber sliver. The dissolution temperature of the water-soluble PVA fiber is 40℃, and the average length of the water-soluble PVA fiber is 51 mm. The speed of the carding machine's licker-in roller is controlled at 680 rpm, the cylinder speed at 300 rpm, and the flats speed at 90 rpm.

[0055] Step 2, Preparation of the mixed sliver of water-soluble polyvinyl alcohol (PVA) fiber and metal fiber: The single water-soluble PVA fiber sliver prepared in Step 1 and the metal fiber sliver are mixed in different proportions using a drawing frame through three blending processes to finally form a mixed sliver of PVA fiber and metal fiber. The proportion of water-soluble PVA fiber sliver is 8%; the metal fiber sliver is made of copper microfiber; the diameter of the metal fibers in the metal fiber sliver is 10 μm, and the average length of the pure metal fibers is 51 mm; the drawing process uses three draws. In the first draw, one water-soluble PVA fiber sliver and ten metal fiber slivers are fed in simultaneously. In the second and third draws, eight blended slivers are fed in to ensure the uniformity of the two different fibers. The final draw weight is controlled at 28 g / 5 m, the bell diameter is 3.6 mm, and the sliver output speed is 140 m / min.

[0056] Step 3, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended yarn: The water-soluble polyvinyl alcohol fiber and metal fiber blended sliver prepared in Step 2 is sequentially passed through a roving frame, a spinning frame, and a loose winding machine to form water-soluble polyvinyl alcohol fiber / metal fiber blended yarn. The roving process parameters are: roving weight 14.0 g / 10m, twist coefficient 80, spindle speed 720 rpm, and back zone draft ratio 1.3; the spinning process parameters are: roller center distance 54 mm × 68 mm, back zone draft ratio 1.37, nip spacing 4.5 mm, twist coefficient 320, and spindle speed 8000 rpm; the volume density of the yarn formed in the winding process is controlled at 0.50 g / cm³.

[0057] Step 4, Preparation of Flexible Pure Metal Short Fiber Yarn or Ply Yarn: Multiple cones of water-soluble polyvinyl alcohol fiber and metal fiber blend prepared in Step 3 are placed in a cone yarn cleaning and drying integrated machine. Different cleaning temperatures, cleaning times, and washing liquid circulation times are set to completely remove the water-soluble polyvinyl alcohol fiber from the blended cones. Then, dehydration is performed, and finally, the yarn is dried at a specific drying temperature to obtain a relatively loosely structured pure metal fiber short fiber yarn I. Yarn I is then double-twisted using a twisting machine to form a stable, fluffy, and soft pure metal fiber short fiber yarn. The cleaning temperature is 60℃, the cleaning time is 20 minutes, the washing liquid circulation time is 15 minutes, the dehydration time is 5 minutes, and the cones are dried at 110℃. The linear density of the flexible pure metal fiber short fiber yarn is 36.9 tex, the twist is 480 twists / m, and the breaking strength is 12.8 cN / tex.

[0058] Depending on the specific circumstances, short fiber single yarns can also be combined, twisted, and plyed to obtain flexible pure metal fiber short fiber ply yarns with a linear density of 36.9 tex × 2.

[0059] Example 3:

[0060] A method for preparing flexible pure metal staple fiber yarn includes step 1, preparation of water-soluble polyvinyl alcohol (PVA) fiber sliver: After unpacking the water-soluble PVA fiber, it is allowed to stand and equilibrate for 24 hours. It is then fed into a blending and opening machine via a condenser. After being opened and impurity removed by the blending and opening machine, the water-soluble PVA fiber is conveyed to a carding machine via a cotton conveying pipe. The carding machine further opens, combs, and removes impurities from the water-soluble PVA fiber layer, causing the crimped fiber clumps to be combed into basically straight single fibers. These fibers are then drawn and aggregated to form a water-soluble PVA fiber sliver. The dissolution temperature of the water-soluble PVA fiber is 60℃, and the average length of the water-soluble PVA fiber is 51 mm. The speed of the carding machine's licker-in roller is controlled at 720 rpm, the cylinder speed at 320 rpm, and the flats speed at 100 rpm.

[0061] Step 2, Preparation of the mixed sliver of water-soluble polyvinyl alcohol (PVA) fiber and metal fiber: The single water-soluble PVA fiber sliver prepared in Step 1 and the metal fiber sliver are mixed in different proportions using a drawing frame through three blending processes to finally form a mixed sliver of PVA fiber and metal fiber. The proportion of water-soluble PVA fiber sliver is 10%; the metal fiber sliver is silver microfiber sliver; the diameter of the metal fiber in the metal fiber sliver is 10 μm, and the average length of the pure metal fiber is 51 mm; the drawing process adopts three drawing processes. In the first drawing process, one water-soluble PVA fiber sliver and seven metal fiber slivers are fed in simultaneously for mixing. In the second and third drawing processes, eight blended slivers are fed in to ensure the uniformity of the two different fibers. The final drawing weight is controlled at 32 g / 5 m, the bell mouth diameter is 3.6 mm, and the sliver output speed is 150 m / min.

[0062] Step 3, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended yarn: The water-soluble polyvinyl alcohol fiber and metal fiber blended sliver prepared in Step 2 is sequentially passed through a roving frame, a spinning frame, and a loose winding machine to form water-soluble polyvinyl alcohol fiber / metal fiber blended yarn. The process parameters for the roving process are: roving weight 15.0 g / 10m, twist coefficient 90, spindle speed 650 rpm, and back zone draft ratio 1.3; the process parameters for the spinning process are: roller center distance 54 mm × 68 mm, back zone draft ratio 1.40, nip spacing 4.5 mm, twist coefficient 350, and spindle speed 9000 rpm; the bulk density of the yarn formed in the winding process is controlled at 0.50 g / cm³.

[0063] Step 4, Preparation of Flexible Pure Metal Short Fiber Yarn or Ply Yarn: Multiple cones of water-soluble polyvinyl alcohol fiber and metal fiber blend prepared in Step 3 are placed in a cone yarn cleaning and drying machine. Different cleaning temperatures, cleaning times, and washing liquid circulation times are set to completely remove the water-soluble polyvinyl alcohol fiber from the blended cones. Then, dehydration is performed, and finally, the yarn is dried at a specific drying temperature to obtain a relatively loosely structured pure metal fiber short fiber yarn I. Yarn I is then double-twisted using a twisting machine to form a stable, fluffy, and soft pure metal fiber short fiber yarn. The cleaning temperature is 80℃, the cleaning time is 20 minutes, the washing liquid circulation time is 15 minutes, the dehydration time is 5 minutes, and the cones are dried at 120℃. The linear density of the flexible pure metal fiber short fiber yarn is 28.1 tex, the twist is 580 twists / m, and the breaking strength is 11.2 cN / tex.

[0064] Depending on the specific circumstances, short fiber single yarns can also be plyed, twisted, and combined to obtain flexible pure metal fiber short fiber ply yarns with a linear density of 28.1 tex × 2.

[0065] Example 4:

[0066] A method for preparing flexible pure metal staple fiber yarn includes step 1, preparation of water-soluble polyvinyl alcohol (PVA) fiber sliver: After unpacking the water-soluble PVA fiber, it is allowed to stand and equilibrate for 24 hours. It is then fed into a blending and opening machine via a condenser. After being opened and impurity removed by the blending and opening machine, the water-soluble PVA fiber is conveyed to a carding machine via a cotton conveying pipe. The carding machine further opens, combs, and removes impurities from the water-soluble PVA fiber layer, causing the crimped fiber clumps to be combed into basically straight single fibers. These fibers are then drawn and aggregated to form a water-soluble PVA fiber sliver. The dissolution temperature of the water-soluble PVA fiber is 40℃, and the average length of the water-soluble PVA fiber is 51 mm. The speed of the carding machine's licker-in roller is controlled at 680 rpm, the cylinder speed at 300 rpm, and the flats speed at 90 rpm.

[0067] Step 2, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended sliver: The single water-soluble polyvinyl alcohol fiber sliver prepared in Step 1 and the metal fiber sliver are mixed in different proportions using a drawing frame through three blending processes to finally form a blended polyvinyl alcohol fiber and metal fiber sliver. The water-soluble polyvinyl alcohol fiber sliver accounts for 8% of the total sliver. The metal fiber sliver is made of stainless steel. The diameter of the metal fibers in the metal fiber sliver is 10 μm, and the average length of the pure metal fibers is 51 mm. The drawing process uses three draws. In the first draw, one water-soluble polyvinyl alcohol fiber sliver and ten metal fiber slivers are fed in simultaneously. In the second and third draws, eight blended slivers are fed in to ensure the uniformity of the two different fibers. The final draw weight is controlled at 32 g / 5 m, the bell diameter is 3.6 mm, and the sliver output speed is 150 m / min.

[0068] Step 3, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended yarn: The water-soluble polyvinyl alcohol fiber and metal fiber blended sliver prepared in Step 2 is sequentially passed through a roving frame, a spinning frame, and a loose winding machine to form water-soluble polyvinyl alcohol fiber / metal fiber blended yarn. The process parameters for the roving process are: roving weight 14.0 g / 10m, twist coefficient 80, spindle speed 550 rpm, and back zone draft ratio 1.3; the process parameters for the spinning process are: roller center distance 54 mm × 68 mm, back zone draft ratio 1.40, nip spacing 4.5 mm, twist coefficient 300, and spindle speed 7500 rpm; the bulk density of the yarn formed in the winding process is controlled at 0.50 g / cm³.

[0069] Step 4, Preparation of Flexible Pure Metal Short Fiber Yarn or Ply Yarn: Multiple cones of water-soluble polyvinyl alcohol fiber and metal fiber blend prepared in Step 3 are placed in a cone yarn cleaning and drying machine. Different cleaning temperatures, cleaning times, and washing liquid circulation times are set to completely remove the water-soluble polyvinyl alcohol fiber from the blended cones. Then, dehydration is performed, and finally, the yarn is dried at a specific drying temperature to obtain a relatively loosely structured pure metal fiber short fiber yarn I. Yarn I is then double-twisted using a twisting machine to form a stable, fluffy, and soft pure metal fiber short fiber yarn. The cleaning temperature is 80℃, the cleaning time is 18 minutes, the washing liquid circulation time is 15 minutes, the dehydration time is 5 minutes, and the cones are dried at 120℃. The linear density of the flexible pure metal fiber short fiber yarn is 24.6 tex, the twist is 580 twists / m, and the breaking strength is 10.0 cN / tex.

[0070] Depending on the specific circumstances, short fiber single yarns can also be plyed, twisted, and combined to obtain flexible pure metal fiber short fiber ply yarns with a linear density of 24.6ex×2.

[0071] To verify the quality of the flexible pure metal staple fiber yarn spun according to the present invention, the yarn quality indicators of the flexible pure metal staple fiber yarns prepared in Examples 1-4 were tested, and the test results are shown in Table 1:

[0072]

[0073] Principles and steps not explicitly described in this invention are all obtainable by those skilled in the art through conventional technical means, and therefore will not be elaborated upon. Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a flexible pure metal staple fiber yarn, comprising the following steps: Step 1, Preparation of water-soluble polyvinyl alcohol fiber sliver: After unpacking the water-soluble polyvinyl alcohol fiber, it is allowed to stand and equilibrate for 24 hours. Then, it is fed into the cotton blending machine through the cotton condenser. After being opened and cleaned by the cotton blending machine, the water-soluble polyvinyl alcohol fiber is transported to the carding machine through the cotton conveying pipe. The carding machine further opens, combs and cleans the water-soluble polyvinyl alcohol fiber, so that the curled fiber clumps are combed into basically straight single fibers. After being drawn and assembled, water-soluble polyvinyl alcohol fiber sliver is formed. Step 2, Preparation of the water-soluble polyvinyl alcohol fiber and metal fiber mixed sliver: The single water-soluble polyvinyl alcohol fiber sliver prepared in Step 1 is mixed with the metal fiber sliver in different proportions using a drawing frame through three blending processes to finally form the water-soluble polyvinyl alcohol fiber and metal fiber mixed sliver; the drawing process in Step 2 adopts three-stage drawing, wherein, The first sliver is mixed by feeding in one water-soluble polyvinyl alcohol fiber sliver and 7-11 metal fiber slivers simultaneously. The second and third slivers are mixed by feeding in 8 blended slivers to ensure the uniformity of the two different fibers. The sliver weight is controlled at 25-35 g / 5m, the bell diameter is 3.6 mm, and the sliver output speed is 130-150 m / min. Step 3, Preparation of water-soluble polyvinyl alcohol fiber and metal fiber blended yarn: The water-soluble polyvinyl alcohol fiber and metal fiber blended sliver prepared in Step 2 are passed through a roving frame, a spinning frame and a loose winding machine in sequence to form water-soluble polyvinyl alcohol fiber / metal fiber blended yarn. Step 4, Preparation of flexible pure metal staple fiber single yarn or ply yarn: The water-soluble polyvinyl alcohol fiber and metal fiber blended yarn prepared in Step 3 are placed in a yarn washing and drying integrated machine. Different washing temperatures, washing times and washing liquid circulation times are set to completely remove the water-soluble polyvinyl alcohol fiber from the blended yarn. Then, it is dehydrated and finally dried at a certain drying temperature to obtain a relatively loose pure metal fiber staple fiber single yarn I. Then, the single yarn I is twisted a second time using a twisting machine to form a flexible pure metal fiber staple fiber single yarn with a stable, fluffy and soft yarn structure.

2. The method for preparing flexible pure metal staple fiber yarn as described in claim 1, wherein the dissolution temperature of the water-soluble polyvinyl alcohol fiber in step 1 is 20-60℃, the average length of the water-soluble polyvinyl alcohol fiber is 38-51mm; the speed range of the carding machine licker-in roller is 660-720 rpm, the cylinder speed range is 280-320 rpm, the flats speed range is 80-100 rpm, and the sliver weight is between 12.0-15.0 g / 5m.

3. In the method for preparing flexible pure metal staple yarn as described in claim 1, the proportion of water-soluble polyvinyl alcohol fiber sliver in step 2 is 5% to 10%.

4. The method for preparing flexible pure metal staple yarn as described in claim 1, wherein the metal fiber sliver in step 2 includes stainless steel metal fiber sliver, copper microfiber sliver, and silver microfiber sliver, and the pure metal fiber has a diameter of 6-10 μm and an average length of 38-51 mm.

5. The method for preparing flexible pure metal staple fiber yarn as described in claim 1, wherein the process parameters for the roving process in step 3 are: roving weight 10.0-15.0 g / 10m, twist coefficient 70-90, spindle speed 500-800 rpm, and back zone draft ratio 1.

3.

6. The method for preparing flexible pure metal staple fiber yarn as described in claim 1, wherein the process parameters for the spinning process in step 3 are: roller center distance 54mm×68mm, back zone draft ratio 1.2~1.5, nip spacing 4.5mm, twist coefficient 280~350, spindle speed 7000~9000 rpm, and bulk density of the yarn package 0.35~0.50g / cm³.

7. The method for preparing flexible pure metal staple fiber yarn as described in claim 1, wherein the cleaning temperature in step 4 is 40-80°C, the cleaning time is 15-20 minutes, the forward and reverse circulation time of the washing liquid is 10-15 minutes, the dehydration time is 2-5 minutes, and the yarn is dried at 100-120°C.

8. The method for preparing flexible pure metal staple fiber yarn as described in claim 1, wherein the linear density of the flexible pure metal staple fiber single yarn in step 4 is 24.6 to 59.0 tex, the twist is 450 to 580 twists / m, and the breaking strength is 10.0 to 15.0 cN / tex.

9. In the method for preparing flexible pure metal staple fiber yarn as described in claim 1, in step 4, flexible pure metal staple fiber single yarns are combined, twisted, and plyed to obtain flexible pure metal staple fiber ply yarn.

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