Basalt Fiber Layered Cross-Wrapped Elastic Skin-Friendly Yarn and Its Preparation Method

Abstract

This invention provides a layered, cross-coated, elastic, skin-friendly yarn made of basalt fibers and its preparation method. The yarn comprises, from the inside out, an elastic core yarn, a basalt fiber layer, and a flame-retardant fiber layer. First, a hollow-spindle fancy twisting device is used to spirally and cross-wrap basalt fibers around the surface of the elastic core yarn, forming a spring-like elastic basalt fiber composite core yarn. The basalt fibers do not self-twist, avoiding fiber structure damage caused by self-twist and imparting high strength and elasticity to the composite core yarn. Then, flame-retardant fibers are coated onto the elastic basalt fiber composite core yarn using friction spinning. During the coating process, the composite core yarn does not twist, avoiding loss of the mechanical properties of the basalt fibers. This invention, through the synergistic combination of the hollow-spindle fancy twisting device and friction spinning, forms a skin-friendly yarn with good mechanical properties, high elasticity, and strong flame-retardant and heat-insulating properties. This yarn is suitable for materials such as fire rescue ropes, fire suits, fire blankets, and fire tents.

Description

Technical Field

[0001] This invention relates to the field of textile technology, and in particular to a basalt fiber layered cross-wrapped elastic skin-friendly yarn and its preparation method. Background Technology

[0002] With the emission of greenhouse gases and the increasing frequency of extreme temperature weather, the probability of open flames or explosions in working environments such as metallurgy, chemical industry, and fire protection has increased. Therefore, in actual production, it is strictly required that relevant positions be equipped with flame-retardant work clothes to protect workers from harm from open flames or heat sources. This requires that the fabric materials of the work clothes have flame-retardant and heat-insulating properties, as well as a certain degree of comfort to ensure the comfort of the workers.

[0003] Basalt fiber possesses excellent flame-retardant and heat-insulating properties, with a wide operating range from -269℃ to 650℃. It exhibits characteristics such as no melting or dripping at high temperatures, high strength, and high modulus. Furthermore, basalt fiber boasts superior properties including high-temperature resistance, oxidation resistance, radiation resistance, heat and sound insulation, and adaptability to various environments, while also offering high cost-effectiveness. However, basalt fiber is brittle, lacks flexibility, and has poor weavability. Therefore, in existing technologies using basalt fiber to prepare flame-retardant and heat-insulating materials, basalt fiber is generally used as the core yarn, covered with a flexible fiber to create a core-spun yarn, thus reducing the degree of bending and damage to the basalt fiber. For example, an invention patent (application number CN 201110076746.7) discloses a basalt core-spun yarn, in which a mixed yarn is wound around a basalt monofilament. The basalt core-spun yarn can be made into a flame-retardant woven fabric. However, since the core-spun yarn uses basalt monofilament as the core yarn, the yarn as a whole is restricted by the basalt monofilament, resulting in poor elasticity and which is not conducive to the comfort of the fabric.

[0004] To address the aforementioned issues, an invention patent (application number CN 202010764123.8) discloses a high-rigidity brittle fiber material non-destructive coating yarn, its spinning method, and the fabric thereof. This method involves forward compound twisting of the high-rigidity brittle fiber, held between flexible fibers, at a twist below the maximum breaking torque of the high-rigidity brittle fiber filament (basalt fiber), forming a composite yarn core. Then, friction spinning and a doubling twister are used to twist and ply the yarn, resulting in a fabric with excellent performance. This method uses flexible fibers and basalt fibers in a doubling twist to increase the flexibility of the composite yarn. However, this method requires a twist below the maximum breaking torque of the basalt fiber to avoid breakage. This results in a loose composite yarn core structure, increasing the burden on subsequent friction spinning. Furthermore, the doubling twist method introduces a certain degree of twist into the basalt fiber itself, easily causing surface damage. The subsequent forward twisting and reverse untwisting using a doubling twister further negatively impacts the strength of the basalt fiber and the entire composite yarn, thus affecting the fabric's performance.

[0005] In view of this, it is necessary to design an improved basalt fiber layered cross-wrapped elastic skin-friendly yarn and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a basalt fiber layered cross-coated elastic skin-friendly yarn and its preparation method. The method involves using a hollow spindle fancy twisting device to wind basalt fibers onto an elastic core yarn to form a spring-like elastic basalt fiber composite core yarn. Flame-retardant fibers are then further coated onto the surface using friction spinning to form a skin-friendly yarn with good mechanical properties and flame-retardant and heat-insulating effects, thereby overcoming the defects of existing basalt fiber fabrics in weaving and application.

[0007] To achieve the above-mentioned objectives, this invention provides a basalt fiber layered cross-wrapped elastic skin-friendly yarn, comprising, from the inside out, an elastic core yarn, a basalt fiber layer, and a flame-retardant fiber layer. The basalt fibers in the basalt fiber layer are spirally wound around the elastic core yarn, and the basalt fibers and the elastic core yarn form a spring-like structure. The breaking elongation of the basalt fiber layered cross-wrapped elastic skin-friendly yarn is 100% to 200%.

[0008] As a further improvement of the present invention, the linear density of the basalt fiber is 8 tex to 50 tex, and the number of the helical basalt fibers is 2 to 8.

[0009] As a further improvement of the present invention, the elastic core yarn is a spandex elastic filament or an elastic silicone tube, wherein the diameter of the spandex elastic filament is 15 to 560 denier, and the diameter of the elastic silicone tube is 0.1 to 2.0 mm.

[0010] As a further improvement of the present invention, it includes one or more of flame-retardant nylon, aramid 1313, flame-retardant viscose, flame-retardant acrylic, seaweed fiber, and polyimide fiber.

[0011] This invention also provides a method for preparing a basalt fiber layered cross-coated elastic skin-friendly yarn, comprising the following steps:

[0012] S1. The elastic core yarn unwound from the yarn tube is fed into the upper hollow yarn path channel of the upper hollow spindle via the feeding mechanism of the hollow spindle fancy twisting device. The basalt filament fibers unwound from the hollow spindle yarn tube package inserted on the outer surface of the upper hollow spindle enter the upper hollow yarn path channel and intersect with the elastic core yarn in the upper hollow yarn path channel. Under the high-speed rotation of the hollow spindle yarn tube package driven by the upper hollow spindle, the basalt filament fibers are wound in the forward direction around the surface of the elastic core yarn, forming a unidirectional basalt fiber wrapped elastic yarn. After the unidirectional basalt fiber wrapped elastic yarn is output from the upper hollow yarn path channel, it enters the lower hollow yarn path channel of the lower hollow spindle. Basalt filament fibers unwound from the hollow spindle yarn tube package inserted on the outer surface of the lower hollow spindle enter the lower hollow yarn channel and intersect with the basalt fiber unidirectional wrapped elastic yarn in the lower hollow yarn channel. Under the high-speed rotation of the hollow spindle and the hollow spindle yarn tube package driven by the lower hollow spindle, the basalt filament fibers reverse-wind around the surface of the basalt fiber unidirectional wrapped elastic yarn, forming a spring-like structure of basalt fiber cross-wrap elastic composite core yarn. The basalt fiber cross-wrap elastic composite core yarn passes through the lower hollow yarn channel, is then output by the output mechanism, and wound by the winding mechanism, finally forming an elastic basalt fiber composite core yarn package.

[0013] S2. The elastic basalt fiber composite core yarn roll from step S1 is placed in the core material storage bin of the friction spinning machine. The elastic basalt fiber composite core yarn unwound from the roll is fed into a wedge-shaped groove formed by a pair of dust cages rotating in the same direction through the yarn guide hole and tension guide of the feeding unit of the friction spinning machine. Simultaneously, the flame-retardant fiber strip is sequentially drafted by the drafting mechanism of the friction spinning machine and combed by the combing roller to form a flame-retardant fiber sliver. The flame-retardant fiber sliver enters the wedge-shaped groove through the fiber conveying channel and merges with the elastic basalt fiber composite core yarn. Under the action of the surfaces of the two dust cages rotating in the same direction, the flame-retardant fiber sliver obtains upward and downward frictional forces on both sides, causing the flame-retardant fiber sliver to wrap around the surface of the elastic basalt fiber composite core yarn, forming a basalt fiber layered cross-wrapped elastic skin-friendly yarn. The basalt fiber layered cross-wrapped elastic skin-friendly yarn is output through the output unit and finally wound onto a roll.

[0014] As a further improvement of the present invention, in step S1, the rotational speed of the upper hollow ingot is 2800-3200 r / min, and the rotational speed of the lower hollow ingot is 2300-2800 r / min.

[0015] As a further improvement of the present invention, in step S1, the feeding mechanism includes a feeding guide rod and a feeding roller arranged sequentially along the input direction of the elastic core yarn, and the feeding speed of the elastic core yarn is 1.5 to 30 m / min.

[0016] As a further improvement of the present invention, the output mechanism includes an output guide rod and an output roller arranged sequentially along the yarn conveying direction, and the output speed of the basalt fiber cross-wrapped elastic composite core yarn is 1.5 to 30 m / min.

[0017] As a further improvement of the present invention, in step S2, the rotation speed of the two dust cages is 3800-9200 r / min, the output speed of the basalt fiber layered cross-wrapped elastic skin-friendly yarn is 6-23 m / min, and the winding speed is 9-25 m / min.

[0018] As a further improvement of the present invention, the tension guide is used to clamp the elastic basalt fiber composite core yarn and, in conjunction with the output speed, adjust the tension of the elastic basalt fiber composite core yarn so that its elongation is 5% to 10%.

[0019] As a further improvement of the present invention, in step S2, the rotational speed of the combing roller is 3200 to 7800 r / min.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention discloses a basalt fiber layered cross-wrapped elastic skin-friendly yarn, comprising, from the inside out, an elastic core yarn, a basalt fiber layer, and a flame-retardant fiber layer. The basalt fibers in the basalt fiber layer are spirally and cross-wound around the elastic core yarn, forming a spring-like structure. The resulting basalt fiber layered cross-wrapped elastic skin-friendly yarn has a breaking elongation of 100%–200%. This invention overcomes the technical prejudice in the prior art that basalt fibers, due to their high rigidity and brittleness, can only be used as core yarns in core-spun yarns. Through a specific preparation method, a spring-like structure of basalt fibers wrapping an elastic core yarn is obtained. This composite yarn has good elasticity. After further coating its surface with flame-retardant fibers, a skin-friendly yarn with good mechanical properties and flame-retardant and heat-insulating effects is formed. This yarn is suitable for materials such as fire rescue ropes, fire suits, fire blankets, and fire tents.

[0022] 2. This invention utilizes a hollow spindle fancy twisting device to spirally and cross-wind at least two basalt fibers onto the surface of an elastic core yarn. Simultaneously, it controls the input speed of the elastic core yarn, the rotational speed of the upper and lower hollow spindles, and the type and diameter of the core yarn to control the pitch of the basalt fibers on the elastic core yarn surface, thus preventing fiber breakage. Furthermore, in the elastic basalt fiber composite core yarn with a spring-like structure produced by the hollow spindle fancy twisting device, the basalt fibers do not self-twist, only exhibit winding twist, avoiding the structural damage caused by basalt fiber self-twist in existing technologies. This imparts high strength and high elasticity to the composite core yarn. In addition, by controlling the rotational speed and direction of the upper and lower hollow spindles, this invention causes two or more basalt fibers to cross-wrap on the elastic core yarn surface during winding, achieving cross-coating of the elastic core yarn. This not only comprehensively improves the flame-retardant and heat-insulating properties of the yarn but also enhances its mechanical properties, giving the yarn a promising application prospect.

[0023] 3. This invention uses friction spinning to coat the elastic basalt fiber composite core yarn with flame-retardant fibers. In this way, the composite core yarn will not generate twist during the coating process, thus avoiding the loss of mechanical properties of basalt fibers. Furthermore, by coordinating the tension guide, the rotation speed of the dust cage, and the output unit, the tension of the composite core yarn is adjusted, so that the elastic basalt fiber composite core yarn is coated with flame-retardant fibers under tension. This not only improves the coating effect of flame-retardant fibers but also reduces the interfacial friction of the composite core yarn, which is beneficial to improving the comfort of the final basalt fiber layered cross-coated elastic skin-friendly yarn. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the fancy twisting device in the method for preparing basalt fiber layered cross-wrapped elastic skin-friendly yarn of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the friction spinning machine in the method for preparing basalt fiber layered cross-wrapped elastic skin-friendly yarn of the present invention.

[0026] Figure 3 This is a microstructure diagram of the elastic basalt fiber composite core yarn in Example 1.

[0027] Figure 4 This is a microscopic image of the basalt fiber layered cross-wrapped elastic skin-friendly yarn prepared in Example 1.

[0028] Figure 5 for Figure 4 Cross-sectional view of medium elastic skin-friendly yarn.

[0029] Figure 6 The diagram shows the testing process and results of the flame retardant properties of yarn in Example 1 and Comparative Examples 1-2.

[0030] Figure Labels

[0031] 100-Hollow spindle fancy twisting device; 110-Feeding mechanism; 111-Feeding guide rod; 112-Feeding roller; 121-Upper hollow spindle; 122-Lower hollow spindle; 130-Hollow spindle yarn tube winding; 140-Output mechanism; 141-Output guide rod; 142-Output roller; 150-Yarn tube; 160-Winding mechanism; 200-Friction spinning machine; 210-Feeding unit; 211-Yarn guide hole; 212-Tension yarn guide; 220-Dust cage; 231-Drafting mechanism; 232-Card roller; 233-Card cover plate; 240-Output unit; 241-Yarn feed roller nip; 242-Yarn guide hook; 243-Yarn guide traverse device; 250-Bowl; 260-Core material storage bin. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0034] Additionally, it should be noted that 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.

[0035] A layered, cross-wrapped, elastic, skin-friendly yarn made of basalt fiber comprises, from the inside out, an elastic core yarn, a basalt fiber layer, and a flame-retardant fiber layer. At least two basalt fibers in the basalt fiber layer are spirally and cross-wound around the elastic core yarn, forming a spring-like structure. The breaking elongation of the layered, cross-wrapped, elastic, skin-friendly yarn made of basalt fiber has a breaking elongation of 100%–200%. This invention overcomes the technical prejudice in the prior art that basalt fiber, due to its high rigidity and brittleness, can only be used as a core yarn in core-spun yarns. Through a specific preparation method, a spring-like structure of basalt fiber wrapping an elastic core yarn is obtained. This composite structure yarn has good elasticity, and the surface is further coated with flame-retardant fibers, improving the comfort of the yarn. Finally, a skin-friendly yarn with good mechanical properties and flame-retardant and heat-insulating effects is obtained. This yarn is suitable for materials such as fire rescue ropes, fire suits, fire blankets, and fire tents, and provides high comfort during application.

[0036] Specifically, the linear density of the basalt fiber is 8 tex to 50 tex, and the number of basalt fibers spirally wound around the surface of the elastic core yarn is 2 to 8. It should be noted that the specification of the basalt fiber cannot be too fine or too coarse. Basalt fibers that are too fine are prone to breakage during the winding process, while basalt fibers that are too coarse make it difficult for the elastic core yarn to be supported, making it difficult to form a spiral structure of basalt fiber covering the elastic core yarn.

[0037] More specifically, the elastic core yarn is made of spandex elastic filament or elastic silicone tubing. The diameter of the spandex elastic filament is 15–560 denier, and the diameter of the elastic silicone tubing is 0.1–2.0 mm. The raw materials for the flame-retardant fiber layer include one or more of flame-retardant nylon, aramid 1313, flame-retardant viscose, flame-retardant acrylic, seaweed fiber, and polyimide fiber. In actual production, when spandex elastic filament is used as the core yarn, its small diameter can easily burden the winding of basalt fibers. Therefore, it is necessary to adjust the input speed of the elastic core yarn (increase) and the rotation speed of the upper and lower hollow spindles (decrease) to adjust the pitch of the basalt fibers on the surface of the elastic core yarn, preventing breakage of the basalt fibers. At the same time, increasing the amount of basalt fibers covering the surface ensures the coating effect and prevents core leakage. When elastic silicone tubing is used as the elastic core yarn, the input speed of the silicone tubing can be slowed down, and the rotation speed of the hollow spindles can be increased to better coat the basalt fibers on the surface of the silicone tubing.

[0038] This invention also provides a method for preparing a basalt fiber layered cross-coated elastic skin-friendly yarn, comprising the following steps:

[0039] S1. The elastic core yarn unwound from the yarn tube 150 is fed into the upper hollow yarn path channel of the upper hollow spindle 121 via the feeding mechanism 110 of the hollow spindle fancy twisting device 100. The basalt filament fibers unwound from the hollow spindle yarn tube package 130 inserted on the outer surface of the upper hollow spindle 121 enter the upper hollow yarn path channel and intersect with the elastic core yarn in the upper hollow yarn path channel. Under the high-speed rotation of the hollow spindle yarn tube package 130 driven by the upper hollow spindle 121, the basalt filament fibers are wound in the forward direction on the surface of the elastic core yarn, forming a unidirectional basalt fiber wrapped elastic yarn. After the unidirectional basalt fiber wrapped elastic yarn is output from the upper hollow yarn path channel, it enters the lower hollow spindle 122. Basalt filament fibers unwound from the hollow spindle yarn tube roll 130, which is inserted on the outer surface of the lower hollow spindle 122, enter the lower hollow yarn channel and intersect with the basalt fiber unidirectional wrapped elastic yarn in the lower hollow yarn channel. Under the high-speed rotation of the hollow spindle 122 and the hollow spindle yarn tube roll 130, the basalt filament fibers reverse-wind around the surface of the basalt fiber unidirectional wrapped elastic yarn, forming a spring-like structure of basalt fiber cross-wrap elastic composite core yarn. The basalt fiber cross-wrap elastic composite core yarn passes through the lower hollow yarn channel, is then output by the output mechanism 140, and wound by the winding mechanism 160, finally forming an elastic basalt fiber composite core yarn roll.

[0040] S2. The elastic basalt fiber composite core yarn roll from step S1 is placed in the core material storage bin 260 of the friction spinning machine 200. The elastic basalt fiber composite core yarn unwound from the elastic basalt fiber composite core yarn roll is fed into the wedge-shaped groove formed by a pair of dust cages 220 rotating in the same direction through the yarn guide hole 211 and tension yarn guide 212 of the feeding unit 210 of the friction spinning machine 200. At the same time, the flame-retardant fiber strip is sequentially drafted by the drafting mechanism 231 and combed by the combing roller 232 of the friction spinning machine 200. The flame-retardant fiber sliver is then formed. The flame-retardant fiber sliver enters the wedge groove through the fiber feeding channel and merges with the elastic basalt fiber composite core yarn. Under the action of the two dust cages 220 rotating in the same direction, the flame-retardant fiber sliver obtains upward and downward frictional forces on both sides, which causes the flame-retardant fiber sliver to wrap around the surface of the elastic basalt fiber composite core yarn, forming a basalt fiber layered cross-wrapped elastic skin-friendly yarn. The basalt fiber layered cross-wrapped elastic skin-friendly yarn is output through the output unit 240 and finally wound onto the drum.

[0041] Specifically, this invention uses a hollow spindle fancy twisting device 100 to spirally and crosswise wind basalt fibers onto the surface of an elastic core yarn. Simultaneously, it controls the input speed of the elastic core yarn, the rotational speed of the upper and lower hollow spindles, and the type and diameter of the core yarn to control the pitch of the basalt fibers on the surface of the elastic core yarn, thus preventing breakage of the basalt fibers. Furthermore, in the elastic basalt fiber composite core yarn with a spring-like structure produced by the hollow spindle fancy twisting device 100, the basalt fibers do not undergo self-twisting; only winding twist is generated. This avoids the structural loss caused by self-twisting of basalt fibers in existing technologies, resulting in composite core yarn with high mechanical properties and good elasticity.

[0042] Please see Figure 1 As shown, the upper hollow spindle 121 rotates at a speed of 2800–3200 r / min, and the lower hollow spindle 122 rotates at a speed of 2300–2800 r / min. This invention controls the rotation speed or direction of the upper and lower hollow spindles, causing two or more basalt fibers to cross-wrap on the surface of the elastic core yarn during winding, thus achieving cross-coating of the elastic core yarn. This not only comprehensively improves the flame-retardant and heat-insulating properties of the yarn but also enhances its mechanical properties, giving the yarn a promising application prospect.

[0043] Specifically, in step S1, the feeding mechanism 110 includes a feeding guide rod 111 and a feeding roller 112 arranged sequentially along the input direction of the elastic core yarn. The feeding speed of the elastic core yarn is controlled by the feeding roller 112, ranging from 1.5 to 30 m / min. The output mechanism 140 includes an output guide rod 141 and an output roller 142 arranged sequentially along the yarn conveying direction. The output speed of the basalt fiber cross-wound elastic composite core yarn is controlled by the output roller 142, ranging from 1.5 to 30 m / min. By controlling the rotational speeds of the feeding roller 112 and the output roller 142, the elastic core yarn remains essentially in a natural state during the basalt winding process, which is beneficial to the stability of the spring-like structure formed after the basalt fiber coats the elastic core yarn.

[0044] In step S2, the present invention uses friction spinning to coat the elastic basalt fiber composite core yarn with flame-retardant fibers. In this method, the composite core yarn does not generate twist during the coating process, thus avoiding any loss to the structure and strength of the basalt fiber. Through the coordinated operation of the hollow spindle fancy twisting device 100 and the friction spinning, a three-layer composite yarn with basalt fiber coating the elastic core yarn and flame-retardant fiber coating the surface is obtained. This yarn not only possesses flame-retardant and heat-insulating properties but also exhibits the elastic properties lacking in existing basalt fibers and basalt composite fibers, and possesses high elasticity.

[0045] Please see Figure 2As shown, the tension guide 212 of the feeding unit 210 is used to clamp the elastic basalt fiber composite core yarn. In conjunction with the output speed, the tension of the elastic basalt fiber composite core yarn is adjusted to achieve an elongation of 5%–10%. The rotational speed of the two dust cages 220 is 3800–9200 r / min, the output speed of the basalt fiber layered cross-wrapped elastic skin-friendly yarn is 6–23 m / min, and the winding speed is 9–25 m / min. Thus, by coordinating the rotational speeds of the tension guide 212 and dust cages 220 with the output unit 240, the tension of the composite core yarn is adjusted, allowing the elastic basalt fiber composite core yarn to be wrapped by flame-retardant fibers under tension. This improves the coating effect of the flame-retardant fibers, reduces the interfacial friction of the composite core yarn, and ultimately enhances the comfort of the final basalt fiber layered cross-wrapped elastic skin-friendly yarn.

[0046] Specifically, the combing roller 232 is further provided with a combing cover plate 233 that wraps around it. After the flame-retardant fiber strip is drawn by the drawing mechanism 231, it is fed into the combing roller 232 and combed into flame-retardant fiber slivers. Under the action of suction, the flame-retardant fiber slivers enter the wedge-shaped grooves formed by the two dust cages 220. The rotational speed of the combing roller 232 is 3200-7800 r / min. In actual production, the feeding speed of the flame-retardant fiber varies according to the number of basalt fibers on the elastic basalt fiber composite core yarn and the diameter of the core yarn. The feeding speed increases with the increase of the number and diameter of the basalt fibers.

[0047] More specifically, the output and take-up of the basalt fiber layered cross-wrapped elastic skin-friendly yarn are accomplished by the output unit 240 and the drum 250, respectively. The output unit 240 includes a yarn feed roller nip 241, a yarn guide hook 242, and a yarn guide traverse device 243. The yarn feed roller nip 241 is located on the side of the dust cage 220, and the yarn guide traverse device 243 is located below the drum 250. The yarn guide traverse device 243 supports the yarn guide hook 242, enabling the lateral movement of the yarn guide hook 242. The yarn output from the dust cage 220 is directly fed into the yarn feed roller nip 241, continues to pass through the yarn guide hook 242, and is wound onto the drum 250 to complete the take-up process.

[0048] In some specific implementations, the elastic basalt fiber composite core yarn needs to be wound onto the winding mechanism 160 and then placed in the core material storage bin 260 of the friction spinning machine 200 before being fed into the friction spinning machine 200 for subsequent coating with flame-retardant fibers.

[0049] In some specific embodiments, the hollow spindle tube roll 130 is formed by winding basalt fibers with Z-twist or S-twist into the hollow spindle tube by the winding device of the fancy twisting device 100, resulting in a hollow spindle tube roll 130 with basalt fibers wound around it, and then mounting it on the upper hollow spindle 121 and / or the lower hollow spindle 122.

[0050] In some specific embodiments, the yarn tube 150 wound with elastic core yarn is suspended on the top yarn rack of the fancy twisting device 100.

[0051] This invention utilizes a hollow spindle fancy twisting device to wind basalt fibers onto an elastic core yarn, forming a highly elastic spring-like structure. Then, a friction spinning machine is used to further coat the surface with flame-retardant fibers, ultimately producing a skin-friendly yarn with good mechanical properties and flame-retardant and heat-insulating effects. Moreover, the basalt fibers in the yarn are not self-twisted and have an intact structure, overcoming the defects of existing basalt fiber fabrics in weaving and application.

[0052] Example 1

[0053] This embodiment provides a method for preparing a layered, cross-wrapped, elastic, skin-friendly yarn made of basalt fiber. The elastic core yarn used is a silicone tube with a diameter of 0.5 mm, the basalt fiber is 25 tex, and the raw material for the flame-retardant fiber is flame-retardant nylon. The method specifically includes the following steps:

[0054] S1. The elastic core yarn unwound from the yarn tube 150 is fed into the upper hollow yarn path channel of the upper hollow spindle 121 via the feeding mechanism 110 of the hollow spindle fancy twisting device 100. The basalt filament fibers unwound from the hollow spindle yarn tube package 130 inserted on the outer surface of the upper hollow spindle 121 enter the upper hollow yarn path channel and intersect with the elastic core yarn in the upper hollow yarn path channel. Under the high-speed rotation of the hollow spindle yarn tube package 130 driven by the upper hollow spindle 121, the basalt filament fibers are wound in the forward direction on the surface of the elastic core yarn, forming a unidirectional basalt fiber wrapped elastic yarn. After the unidirectional basalt fiber wrapped elastic yarn is output from the upper hollow yarn path channel, it enters the lower hollow spindle 122. Basalt filament fibers unwound from the hollow spindle yarn tube roll 130, which is inserted on the outer surface of the lower hollow spindle 122, enter the lower hollow yarn channel and intersect with the basalt fiber unidirectional wrapped elastic yarn in the lower hollow yarn channel. Under the high-speed rotation of the hollow spindle 122 and the hollow spindle yarn tube roll 130, the basalt filament fibers reverse-wind around the surface of the basalt fiber unidirectional wrapped elastic yarn, forming a spring-like structure of basalt fiber cross-wrap elastic composite core yarn. The basalt fiber cross-wrap elastic composite core yarn passes through the lower hollow yarn channel, is then output by the output mechanism 140, and wound by the winding mechanism 160, finally forming an elastic basalt fiber composite core yarn roll.

[0055] Among them, the upper hollow spindle 121 rotates at 3000 r / min, the lower hollow spindle 122 rotates at 2500 r / min, the feeding speed of the elastic core yarn is 2 m / min, and the output speed of the basalt fiber cross-wrapped elastic composite core yarn is 2.5 m / min.

[0056] S2. The elastic basalt fiber composite core yarn roll from step S1 is placed in the core material storage bin 260 of the friction spinning machine 200. The elastic basalt fiber composite core yarn unwound from the elastic basalt fiber composite core yarn roll is fed into the wedge-shaped groove formed by a pair of dust cages 220 rotating in the same direction through the yarn guide hole 211 and tension yarn guide 212 of the feeding unit 210 of the friction spinning machine 200. At the same time, the flame-retardant fiber strip is sequentially drafted by the drafting mechanism 231 and combed by the combing roller 232 of the friction spinning machine 200. The flame-retardant fiber sliver is then formed. The flame-retardant fiber sliver enters the wedge groove through the fiber feeding channel and merges with the elastic basalt fiber composite core yarn. Under the action of the two dust cages 220 rotating in the same direction, the flame-retardant fiber sliver obtains upward and downward frictional forces on both sides, which causes the flame-retardant fiber sliver to wrap around the surface of the elastic basalt fiber composite core yarn, forming a basalt fiber layered cross-wrapped elastic skin-friendly yarn. The basalt fiber layered cross-wrapped elastic skin-friendly yarn is output through the output unit 240 and finally wound onto the drum.

[0057] The elongation rate of the elastic basalt fiber composite core yarn is 10%; the rotation speed of the combing roller 232 is 3500 r / min and the rotation speed of the dust cage 220 is 4000 r / min.

[0058] Please see Figures 3-5 As shown, Figure 3 This is a microstructure diagram of the elastic basalt fiber composite core yarn in Example 1. Figure 4 This is a microscopic image of the basalt fiber layered cross-coated elastic skin-friendly yarn prepared in Example 1. Figure 5 for Figure 4 Cross-sectional view of medium-elasticity, skin-friendly yarn. From Figure 3 As can be seen, under microscope light, the basalt fibers reflect light, and the basalt fibers are evenly coated on the surface of the elastic core yarn. From Figures 4-5 As can be seen, the flame-retardant fibers on the surface of the obtained elastic and skin-friendly yarn are evenly wrapped, and no basalt fibers are exposed.

[0059] Comparative Example 1

[0060] Comparative Example 1 provides a method for preparing pure basalt fibers, which are made by drawing basalt material in a molten state through holes in a platinum-rhodium alloy plate, with a linear density of 25 tex.

[0061] Comparative Example 2

[0062] Comparative Example 2 provides a method for preparing flame-retardant basalt core-spun yarn. Compared with Example 1, the difference is that step S1 is not performed. Instead, the yarn tube wound with basalt fibers is directly placed on the core material storage bin 260 of the friction spinning machine 200 to coat the flame-retardant fibers. The rest is roughly the same as Example 1, and will not be described again here.

[0063] Comparative Example 3

[0064] Comparative Example 3 provides a method for preparing flame-retardant basalt core-spun yarn. Compared with Example 1, the difference is that in step S1, a ring spinning machine is used to twist basalt fibers and elastic core yarn together to obtain composite yarn. The composite yarn is then placed on the core material storage bin 260 of the friction spinning machine 200. The rest is roughly the same as in Example 1, and will not be described again here.

[0065] Comparative Example 4

[0066] Comparative Example 4 provides a method for preparing flame-retardant basalt core-spun yarn. Compared with Example 1, the difference is that in step S1, the feeding speed of the elastic core yarn is 35 m / min, and the output speed of the basalt fiber cross-wrapped elastic composite core yarn is 35 m / min. The rest is roughly the same as in Example 1, and will not be repeated here.

[0067] Comparative Example 5

[0068] Comparative Example 5 provides a method for preparing flame-retardant basalt core-spun yarn. Compared with Example 1, the difference is that in step S1, the rotation speed of the upper hollow spindle 121 is 2800 r / min and the rotation speed of the lower hollow spindle 122 is 2300 r / min. The rest is roughly the same as in Example 1, and will not be repeated here.

[0069] The yarns prepared in Example 1 and Comparative Examples 1-5 were tested for strength, elongation at break, and flame retardancy. The flame retardancy was characterized by burning the yarn with an open flame and measuring the time from burning to breakage. The results are shown in Table 1 below.

[0070] Table 1. Performance test results of the yarns prepared in Example 1 and Comparative Examples 1-5

[0071] Strong (cN) Elongation at break (%) Yarn flame retardant test / s Example 1 1123 233.6 5.01 Comparative Example 1 821.1 2.4 0.64 Comparative Example 2 324.6 2.6 1.05 Comparative Example 3 956.2 3.2 1.36 Comparative Example 4 1056.9 163.9 4.24 Comparative Example 5 1121.5 78.6 3.12

[0072] As shown in Table 1, compared with Comparative Examples 1-3, the basalt fiber layered cross-coated elastic skin-friendly yarn prepared in Example 1 has slightly improved strength, and its elongation at break is much higher than that of the three yarns in Comparative Examples 1-3. Its flame retardant properties are also much higher than those of the three yarns in Comparative Examples 1-3. Compared with Comparative Examples 4-5, the elongation at break of the elastic skin-friendly yarn in Example 1 is higher than that of the two yarns in Comparative Examples 4-5, and its flame retardant properties are also superior to those of the yarns in Comparative Examples 4-5.

[0073] Please see Figure 6The figure shows the test process and results of the flame retardant properties of the yarns in Example 1 and Comparative Examples 1-2. As can be seen from the figure, when the yarns were calcined with an open flame, the yarn prepared in Example 1 turned black but did not break after 3 seconds of calcination, while the yarns in Comparative Examples 1-2 broke after 1 second of calcination. This indicates that the basalt fiber layered cross-wrapped elastic skin-friendly yarn prepared in Example 1 has high flame retardant properties.

[0074] Example 2

[0075] This embodiment provides a method for preparing a layered cross-coated elastic skin-friendly yarn of basalt fiber. Compared with Embodiment 1, the difference is that step S1 is repeated once, that is, four basalt fibers are coated on the surface of the elastic core yarn. The rest is roughly the same as in Embodiment 1, and will not be described again here.

[0076] Example 3

[0077] This embodiment provides a method for preparing a layered cross-coated elastic skin-friendly yarn of basalt fiber. Compared with Embodiment 1, the difference is that step S1 is repeated twice with the obtained elastic basalt fiber composite core yarn, that is, 6 basalt fibers are coated on the surface of the elastic core yarn. The rest is roughly the same as in Embodiment 1, and will not be described again here.

[0078] Example 4

[0079] This embodiment provides a method for preparing a basalt fiber layered cross-coated elastic skin-friendly yarn. Compared with Embodiment 1, the difference is that the basalt fiber is 12.5 tex, and the rest is roughly the same as Embodiment 1, which will not be repeated here.

[0080] Example 5

[0081] This embodiment provides a method for preparing a basalt fiber layered cross-coated elastic skin-friendly yarn. The difference from Embodiment 1 is that the basalt fiber is 50 tex, while the rest is roughly the same as Embodiment 1, and will not be repeated here.

[0082] Comparative Example 6

[0083] Comparative Example 6 provides a method for preparing flame-retardant basalt core-spun yarn. The difference from Example 1 is that the basalt fiber is 75 tex, while the rest is roughly the same as in Example 1, and will not be repeated here.

[0084] The yarns prepared in Examples 2-5 and Comparative Example 6 were tested for strength, elongation at break, and flame retardancy. The flame retardancy was characterized by burning the yarn with an open flame and measuring the time from burning to breakage. The results are shown in Table 2 below.

[0085] Table 2. Performance test results of the yarns prepared in Examples 2-5 and Comparative Example 6.

[0086] Strong (cN) Elongation at break (%) Yarn flame retardant test / s Example 2 1164.7 213.5 5.45 Example 3 1149.4 163.8 6.23 Example 4 621.5 225.9 4.35 Example 5 1462.3 205.6 5.81 Comparative Example 6 624.2 221.6 3.24

[0087] As shown in Table 2, in Examples 1-3, the elongation at break gradually decreased with the increase of the number of basalt fibers wrapped, but the flame retardant performance gradually improved. In actual production, the yarn and preparation parameters can be selected according to the application requirements. In Examples 1 and 4-5, the yarn strength changed with the number of the outer basalt fiber, and the flame retardant performance improved with the increase of the number of basalt fiber. However, in Comparative Example 6, 75tex basalt fiber was used, and the basalt fiber broke during the coating process, making it difficult to obtain elastic composite yarn with good coating effect of basalt fiber coated silicone tube. Therefore, its strength and flame retardant performance were poor.

[0088] In summary, the present invention provides a basalt fiber layered cross-wrapped elastic skin-friendly yarn and its preparation method. The yarn comprises, from the inside out, an elastic core yarn, a basalt fiber layer, and a flame-retardant fiber layer. The basalt fibers in the basalt fiber layer are spirally wound on the elastic core yarn, and the basalt fibers and the elastic core yarn form a spring-like structure. This invention first employs a hollow spindle fancy twisting device to spirally wind basalt fibers onto the surface of an elastic core yarn. Simultaneously, it controls the input speed of the elastic core yarn, the rotational speed of the upper and lower hollow spindles, and the type and diameter of the core yarn to control the pitch of the basalt fibers on the elastic core yarn surface, thus preventing fiber breakage. Furthermore, in the elastic basalt fiber composite core yarn with a spring-like structure produced by the hollow spindle fancy twisting device, the basalt fibers do not undergo self-twisting, only entanglement twist, avoiding the structural loss caused by basalt fiber self-twisting in existing technologies, and endowing the composite core yarn with high strength and high elasticity. Then, it uses friction spinning to coat the elastic basalt fiber composite core yarn with flame-retardant fibers. No twist is generated during the coating process, avoiding loss of the mechanical properties of the basalt fibers. This invention overcomes the technical prejudice that basalt fiber, due to its high rigidity and brittleness, can only be used as core yarn in core-spun yarn. Through the synergistic cooperation of hollow spindle fancy twisting device and friction spinning, a spring-like structure in which basalt fiber wraps the elastic core yarn is obtained. Flame-retardant fiber is then further coated on its surface, forming a layered cross-coated elastic skin-friendly yarn of basalt fiber with good mechanical properties, high elasticity, and strong flame-retardant and heat-insulating properties. This yarn is highly comfortable and has a wide range of applications, suitable for materials such as fire rescue ropes, fire suits, fire blankets, and fire tents.

[0089] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A basalt fiber layered cross-wrapped elastic skin-friendly yarn, characterized in that, The yarn comprises, from the inside out, an elastic core yarn, a basalt fiber layer, and a flame-retardant fiber layer. The basalt fibers in the basalt fiber layer are spirally wound around the elastic core yarn, forming a spring-like structure with the elastic core yarn. The breaking elongation of the basalt fiber layered cross-wrapped elastic skin-friendly yarn is 100%~200%. The preparation method of the basalt fiber layered cross-wrapped elastic skin-friendly yarn includes the following steps: S1. The elastic core yarn unwound from the yarn tube is fed into the upper hollow yarn path channel of the upper hollow spindle via the feeding mechanism of the hollow spindle fancy twisting device. The basalt filament fibers unwound from the hollow spindle yarn tube winding on the outer surface of the upper hollow spindle enter the upper hollow yarn path channel and intersect with the elastic core yarn in the upper hollow yarn path channel. Under the high-speed rotation of the hollow spindle yarn tube winding driven by the upper hollow spindle, the basalt filament fibers are forward-winding around the surface of the elastic core yarn, forming a basalt fiber unidirectional wrapped elastic yarn. After the basalt fiber unidirectional wrapped elastic yarn is output from the upper hollow yarn path channel, it enters the lower hollow yarn path channel of the lower hollow spindle. The basalt filament fibers unwound from the hollow spindle tube on the outer surface of the spindle enter the lower hollow yarn channel, where they intersect with the basalt fiber unidirectionally wrapped elastic yarn. Under the high-speed rotation of the lower hollow spindle and the hollow spindle tube, the basalt filament fibers reverse-wind around the surface of the basalt fiber unidirectionally wrapped elastic yarn, forming a spring-like structure of basalt fiber cross-wrap elastic composite core yarn. This basalt fiber cross-wrap elastic composite core yarn passes through the lower hollow yarn channel, is then output by the output mechanism, and wound by the winding mechanism, ultimately forming an elastic basalt fiber composite core yarn package. The rotation speed of the upper hollow spindle is 3000~3200 r / min, and the rotation speed of the lower hollow spindle is 2500~2800 r / min. S2. The elastic basalt fiber composite core yarn roll from step S1 is placed in the core material storage bin of the friction spinning machine. The elastic basalt fiber composite core yarn unwound from the roll is fed into a wedge-shaped groove formed by a pair of dust cages rotating in the same direction through the yarn guide hole and tension guide of the feeding unit of the friction spinning machine. Simultaneously, the flame-retardant fiber strip is sequentially drafted by the drafting mechanism of the friction spinning machine and combed by the combing roller to form a flame-retardant fiber sliver. The flame-retardant fiber sliver enters the wedge-shaped groove through the fiber conveying channel and merges with the elastic basalt fiber composite core yarn. Under the action of the surfaces of the two dust cages rotating in the same direction, the flame-retardant fiber sliver obtains upward and downward frictional forces on both sides, causing the flame-retardant fiber sliver to wrap around the surface of the elastic basalt fiber composite core yarn, forming a basalt fiber layered cross-wrapped elastic skin-friendly yarn. The basalt fiber layered cross-wrapped elastic skin-friendly yarn is output through the output unit and finally wound onto a roll.

2. The basalt fiber layered cross-wrapped elastic skin-friendly yarn according to claim 1, characterized in that, The linear density of the basalt fiber is 8 tex to 50 tex, and the number of the basalt fibers in a spiral shape is 2 to 8.

3. The basalt fiber layered cross-wrapped elastic skin-friendly yarn according to claim 1, characterized in that, The elastic core yarn is a spandex elastic filament or an elastic silicone tube. The diameter of the spandex elastic filament is 15~560 denier, and the diameter of the elastic silicone tube is 0.1~2.0 mm.

4. The basalt fiber layered cross-wrapped elastic skin-friendly yarn according to claim 1, characterized in that, The raw materials for the flame-retardant fiber layer include one or more of flame-retardant nylon, aramid 1313, flame-retardant viscose, flame-retardant acrylic fiber, seaweed fiber, and polyimide fiber.

5. The basalt fiber layered cross-wrapped elastic skin-friendly yarn according to claim 1, characterized in that, In step S1, the feeding mechanism includes a feeding guide rod and a feeding roller arranged sequentially along the input direction of the elastic core yarn, and the feeding speed of the elastic core yarn is 1.5~30 m / min.

6. The basalt fiber layered cross-wrapped elastic skin-friendly yarn according to claim 5, characterized in that, The output mechanism includes an output guide rod and an output roller arranged sequentially along the yarn conveying direction, and the output speed of the basalt fiber cross-wrapped elastic composite core yarn is 1.5~30 m / min.

7. The basalt fiber layered cross-wrapped elastic skin-friendly yarn according to claim 1, characterized in that, In step S2, the rotation speed of the two dust cages is 3800~9200 r / min, the output speed of the basalt fiber layered cross-wrapped elastic skin-friendly yarn is 6~23 m / min, and the winding speed is 9~25 m / min.

8. The basalt fiber layered cross-wrapped elastic skin-friendly yarn according to claim 1, characterized in that, In step S2, the rotational speed of the combing roller is 3200~7800 r / min.

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