High strength cotton fiber / basalt fiber composite yarn and method of making same

Abstract

The application discloses high-strength cotton fiber / basalt fiber composite yarn and a preparation method thereof, and belongs to the technical field of composite yarns.The composite yarn comprises modified basalt fibers as a core layer and cotton fibers wrapped outside the modified basalt fibers.The composite yarn prepared by the application has good breaking strength, wear resistance, hair resistance and interface adhesion.

Description

Technical Field

[0001] This invention relates to the field of composite yarn technology, specifically to a high-strength cotton fiber / basalt fiber composite yarn and its preparation method. Background Technology

[0002] Cotton fiber is widely used in textiles due to its softness, skin-friendliness, and ease of processing. However, yarns made solely from cotton fiber still have certain shortcomings in terms of breaking strength, abrasion resistance, and structural stability. Basalt fiber, on the other hand, possesses high mechanical strength and good dimensional stability. Combining basalt fiber with cotton fiber can improve the mechanical properties, abrasion resistance, and structural stability of the yarn while maintaining the soft feel and moisture absorption of cotton.

[0003] Currently, cotton / basalt fiber composite yarns are typically produced using core-spun, cover-spun, or blended methods. The core-spun structure, with basalt fiber as the core layer and cotton fiber as the outer cover layer, enhances the reinforcing effect of the basalt fiber and creates an outer cover structure for the cotton fiber, thereby improving the breaking strength and abrasion resistance of the composite yarn to some extent. However, the surface of basalt fiber is relatively smooth, with a limited number of surface-active groups. Its bonding with cotton fiber relies mainly on mechanical entanglement and friction, resulting in insufficient interfacial cohesion. During spinning, twisting, winding, and subsequent use, problems such as uneven cotton fiber coverage, fiber slippage, core filament exposure, and increased hairiness can easily occur. This leads to reduced interfacial load transfer efficiency and increased hairiness index in the composite yarn, ultimately affecting its breaking strength, abrasion resistance, and stability in use.

[0004] Existing technologies typically employ methods such as silane coupling, resin sizing, acid-base etching, plasma treatment, or inorganic particle coating to modify the surface of basalt fibers. While these methods can improve the surface activity or roughness of basalt fibers to some extent, they still have certain shortcomings: for example, the silane coupling layer is relatively thin, making it difficult to significantly improve the interfacial cohesion between basalt fibers and cotton fibers; resin sizing tends to form a continuous resin film on the fiber surface, significantly increasing fiber rigidity and reducing its flexibility, resulting in the two phases of fibers not being able to adhere tightly during twisting and coating, which is not conducive to uniform coating of cotton fibers; the addition of inorganic particle coating mostly relies on physical adsorption, which is prone to falling off during spinning friction and abrasion resistance tests, resulting in unstable interfacial reinforcement and abrasion resistance improvement effects.

[0005] Therefore, there is an urgent need to develop a new process for high-strength cotton fiber / basalt fiber composite yarn to improve the breaking strength and abrasion resistance of the composite yarn. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-strength cotton fiber / basalt fiber composite yarn and its preparation method.

[0007] A high-strength cotton fiber / basalt fiber composite yarn, the composite yarn comprising modified basalt fiber as the core layer and cotton fiber covering the outside of the modified basalt fiber; The mass ratio of the modified basalt fiber to the cotton fiber is 5:(13-18).

[0008] The modified basalt fiber is prepared by the following method: A1: Basalt fibers are subjected to alkaline hydroxylation treatment under the action of sodium hydroxide, and then hydrolyzed and condensed with tetraethyl orthosilicate to obtain silicon oxide basalt fibers. A2: Silica basalt fibers react with magnesium salts, aluminum salts and urea to obtain magnesium-aluminum modified basalt fibers; A3: Magnesium-aluminum modified basalt fibers react with zirconium salts, then with phosphates, and are softened by polyethylene glycol to obtain modified basalt fibers.

[0009] In step A1, the mass ratio of basalt fiber, sodium hydroxide and tetraethyl orthosilicate is 10:(1-2):(1-2.5).

[0010] In step A2, the mass ratio of the silicon oxide basalt fiber, magnesium salt, aluminum salt and urea is 10:(3-7):(2-4):(4-8).

[0011] In step A3, the mass ratio of the magnesium-aluminum modified basalt fiber, zirconium salt, phosphate and polyethylene glycol is 100:(4-6):(2-2.8):(1-2).

[0012] In step A2, the magnesium salt is magnesium nitrate hexahydrate, and the aluminum salt is aluminum nitrate nonahydrate.

[0013] In step A3, the zirconium salt is zirconium oxychloride octahydrate.

[0014] In step A3, the phosphate is sodium dihydrogen phosphate.

[0015] In step A3, the polyethylene glycol is PEG-400.

[0016] This application describes the preparation of modified basalt fibers using basalt fiber twisted yarn as the matrix, achieved through a synergistic process of surface activation, silicon oxide layer construction, magnesium-aluminum inorganic layer deposition, zirconium-phosphorus modification, and PEG softening. First, the basalt fiber twisted yarn is ultrasonically cleaned with ethanol to remove surface dust and weakly adsorbed impurities. Then, treatment with sodium hydroxide aqueous solution causes slight hydrolysis and etching of the Si-O-Si and Al-O-Si bonds on the surface of the basalt monofilaments, forming active hydroxyl groups such as Si-OH and Al-OH on the monofilament surface and increasing surface roughness. Finally, rapid immersion in acetic acid aqueous solution neutralizes residual alkali, preventing alkali residue from remaining inside the twisted yarn and causing a decrease in fiber strength.

[0017] Tetraethyl orthosilicate hydrolyzes in an ethanol / water system to generate silanols. Some of these silanols further condense to form a Si-O-Si network; others condense with hydroxyl groups on the surface of basalt monofilaments to form Si-O-Si or Si-O-Al bonded structures, thus constructing a silica transition layer on the surface of each monofilament in the twisted yarn, providing a stable interface for subsequent inorganic component deposition. Urea slowly decomposes under heating conditions, causing the pH of the system to gradually increase, and Mg... 2+ And Al 3+ In-situ hydrolysis deposition forms magnesium aluminum hydroxide or magnesium aluminum hydrotalcite-like structures on the surface of silicon oxide monofilaments, increasing polar sites and micro-roughened interfaces, thereby improving mechanical interlocking and interfacial friction between the monofilaments and the outer cotton fibers. 4+ Controlled hydrolysis forms Zr-OH, Zr-O-Si, or Zr-OM sites, and phosphate groups coordinate or condense with zirconium hydroxyl groups to form Zr-OP structures, improving the stability of the inorganic layer and interfacial polarity. Finally, PEG-400 forms a flexible lubricating interface on the surface of basalt fiber twisted yarn by hydrogen bonding with the inorganic modification layer through hydroxyl and ether oxygen groups. This helps reduce guide yarn friction and rigid damage, improves unwinding and core-spun stability, and thus enhances the interfacial cohesion, abrasion resistance, and breaking strength of the composite yarn.

[0018] A method for preparing a high-strength cotton fiber / basalt fiber composite yarn, characterized by comprising the following steps: (1) The cotton fibers are subjected to moisture conditioning, opening, impurity removal, carding and drawing to obtain sliver cotton fibers; (2) After the modified basalt fiber is conditioned and balanced, it is unwound and finished. (3) Using modified basalt fiber as the core yarn and cotton fiber sliver as the outer yarn, the core-spun yarn is composite yarn is made by using core-spun yarn, so that the cotton fiber is wrapped around the outside of the modified basalt fiber, and the nascent cotton fiber / basalt fiber composite yarn is obtained. (4) The nascent cotton fiber / basalt fiber composite yarn is wound and shaped to obtain a high-strength cotton fiber / basalt fiber composite yarn.

[0019] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include: The composite yarn prepared in this application exhibits high breaking strength, good abrasion resistance, low hairiness index, and high interfacial cohesion, mainly due to the synergistic effect of cotton fiber pretreatment, basalt fiber surface modification, and core-spun structure. Firstly, after moisture conditioning, opening, airflow impurity removal, further impurity removal, carding, and two drawing processes, impurities, short fibers, and entangled fibers are effectively removed. This improves fiber parallelism, straightness, and evenness, enabling the formation of a continuous and uniform outer layer during subsequent drafting and twisting processes. This reduces weak points and hairiness, thereby improving yarn stability.

[0020] Secondly, after multi-stage surface modification, the basalt fiber twisted yarn forms a silicon oxide layer, a magnesium-aluminum inorganic layer, a zirconium-phosphorus bonding layer, and a PEG flexible interface. The silicon oxide layer increases surface hydroxyl groups and bonding sites, the magnesium-aluminum inorganic layer improves surface roughness and polarity, the zirconium-phosphorus structure enhances the stability and wear resistance of the inorganic layer, and the PEG softening layer reduces guide yarn friction and fiber brittle damage. The basalt fiber surface transforms from a smooth and inert state to a composite interface that combines roughness, polarity, and flexibility, improving its mechanical interlocking, hydrogen bonding, and triboelectric cohesion with the outer cotton fibers.

[0021] The core-spun process of this application uses modified basalt fiber twisted yarn as the core yarn located at the center of the yarn, playing a major reinforcing role and improving the breaking strength and dimensional stability of the composite yarn. Cotton fibers cover the outside of the core yarn, improving the yarn's softness, weaveability, and surface feel, and reducing the exposure of basalt fibers. Winding and hot air relaxation treatment further release the internal stress of spinning, stabilizing twist and moisture regain. Therefore, this composite yarn has high breaking strength, good abrasion resistance, low hairiness index, and high interfacial cohesion. Attached Figure Description

[0022] Figure 1 Scanning electron microscope (SEM) images of basalt fiber raw material, silica basalt fiber prepared in Example 1, magnesium-aluminum modified basalt fiber, and modified basalt fiber.

[0023] Figure 2 Fourier transform infrared (FTIR) spectra of basalt fiber raw material, silicon oxide basalt fiber prepared in Example 1, magnesium-aluminum modified basalt fiber, and modified basalt fiber. Detailed Implementation

[0024] Example 1: Preparation of modified basalt fiber A1: Add 10g of basalt fiber to 100mL of anhydrous ethanol and ultrasonically clean for 15min at 30kHz and 200W. Remove the fiber and add it to a sodium hydroxide aqueous solution made of 1g of sodium hydroxide and 150g of deionized water. Place the solution in a 50℃ constant temperature water bath and stir at 150rpm for 35min to separate the solid and liquid. Collect the fiber and quickly wash it with 100ml of 0.1wt% acetic acid aqueous solution for 2min, then wash with deionized water until the pH of the washing solution reaches 7.0. Then add 150g of anhydrous ethanol and 5g of deionized water... In a mixture of 0 g deionized water, the mixture was stirred and dispersed at 300 rpm for 20 min. Then, 1.0 g tetraethyl orthosilicate was slowly added dropwise over 15 min. The pH was adjusted to 4.5 using a 5 wt% acetic acid aqueous solution, and the mixture was reacted at 45 °C for 2 h. The pH was then adjusted to 8.4 using a 5 wt% ammonia solution, and the mixture was reacted at 45 °C for another 2 h. After solid-liquid separation, the fibers were collected, washed twice with anhydrous ethanol (50 mL each time), washed three times with deionized water (50 mL each time), and dried at 70 °C for 4 h to obtain silicon oxide basalt fibers.

[0025] A2: Add 10g of silicon oxide basalt fiber to 300g of deionized water, add 3.0g of magnesium nitrate hexahydrate, 2.0g of aluminum nitrate nonahydrate and 4.0g of urea, stir at 300rpm for 30min; heat to 90℃ and react for 10h, then cool to room temperature, separate solid and liquid, collect the fiber, wash with deionized water 3 times (100ml each time), and then dry at 70℃ for 6h to obtain magnesium aluminum modified basalt fiber.

[0026] A3: Add 10g of magnesium-aluminum modified basalt fiber to 80g of deionized water, add 0.4g of zirconium oxychloride octahydrate, adjust the pH to 4.8 with 5wt% ammonia, and react at 45℃ for 1h; then add 10mL of aqueous solution containing 0.2g of sodium dihydrogen phosphate dropwise over 20min. During the dropwise addition, maintain the pH of the system at 4.8 with 5wt% ammonia or 0.1mol / L hydrochloric acid solution. Continue to react at 45℃ for 1h, then separate the solid and liquid, collect the fiber, wash it three times with deionized water (50ml each time), and then add 80g of aqueous solution containing 0.1g of polyethylene glycol (PEG-400) for softening treatment. Impregnate at room temperature for 30min, separate the solid and liquid, collect the fiber, and dry it at 70℃ for 4h to obtain modified basalt fiber.

[0027] Depend on Figure 1As can be seen, the surface of the original basalt fiber (BF) is relatively smooth, indicating its low surface activity. After treatment A1, fine particles and a slightly rough structure appear on the fiber surface, indicating that the alkali treatment activates the fiber surface. The hydrolysis and condensation of tetraethyl orthosilicate forms a silicon oxide modification layer, which improves the surface polarity and subsequent deposition sites. The surface roughness of the magnesium-aluminum modified basalt fiber further increases, with visible granular and lamellar deposition, indicating that the Mg-Al component grows in situ on the fiber surface, forming a magnesium-aluminum modification layer, thereby increasing the specific surface area and mechanical interlocking. A relatively continuous composite modification layer is formed on the surface of the modified basalt fiber, while retaining a certain degree of roughness. After treatments A1-A3, the fiber surface morphology gradually changes from smooth to rough, active, and relatively continuous composite interface, indicating that stepwise modification can effectively improve the surface structure of basalt fiber, providing a basis for cotton fiber coating, interfacial cohesion, and improved mechanical properties of composite yarns.

[0028] pass Figure 2 Infrared images show that basalt fibers are present at 470 cm⁻¹. -1 800 cm -1 1045 cm -1 The left and right sides correspond to the bending, symmetrical, and asymmetrical stretching vibrations of the Si-O-Si framework, respectively; after silicon oxidation treatment, 1080 cm -1 Enhanced Si-O-Si asymmetric stretching vibrations at the left and right sides, accompanied by a 960 cm⁻¹ vibration. -1 The presence of characteristic Si-OH peaks at the left and right positions indicates the formation of a silicon-oxygen network layer; after Mg / Al modification, peaks appear at 560-620 cm⁻¹. -1 The Mg-O / Al-O vibrational absorption peak appears at the left and right sides, and at 1365 cm⁻¹ -1 The presence of anion characteristic peaks at the left and right positions indicates the formation of a layered inorganic structure; in the modified basalt fiber sample, at 2920 cm⁻¹... -1 and 2850 cm -1 -CH2- vibrational peaks appeared on both sides, and at 1000 cm⁻¹ -1 The formation of multi-component coupling absorption peaks such as Si-O-Si and Zr-OP at the left and right positions indicates the formation of an inorganic-organic multilayer composite interface structure.

[0029] Example 2 Preparation of modified basalt fiber A1: Add 10g of basalt fiber to 100mL of anhydrous ethanol and ultrasonically clean for 15min at 30kHz and 200W. Remove the fiber and add it to an aqueous solution of sodium hydroxide prepared with 1.5g of sodium hydroxide and 200g of deionized water. Place the solution in a 50℃ constant temperature water bath and stir at 180rpm for 30min to separate the solid and liquid. Collect the fiber and wash it with 100ml of 0.1wt% acetic acid aqueous solution for 2min, then wash with deionized water until the pH of the washing solution reaches 7.0. Then add the fiber to 150g of anhydrous ethanol and 50g of deionized water. The mixture was stirred and dispersed at 300 rpm for 20 min in a solution of deionized water. Then, 1.5 g of tetraethyl orthosilicate was slowly added dropwise over 15 min. The pH was adjusted to 4.8 with 5 wt% acetic acid aqueous solution, and the reaction was carried out at 50 °C for 1.5 h. The pH was then adjusted to 8.5 with 5 wt% ammonia solution, and the reaction was continued at 50 °C for 1.5 h. After solid-liquid separation, the fibers were collected, washed twice with anhydrous ethanol (50 mL each time), washed three times with deionized water (50 mL each time), and dried at 70 °C for 4 h to obtain silicon oxide basalt fibers.

[0030] A2: Add 10g of silicon oxide basalt fiber to 300g of deionized water, add 5.0g of magnesium nitrate hexahydrate, 3.0g of aluminum nitrate nonahydrate and 6.0g of urea, stir at 300rpm for 30min; heat to 95℃ and react for 9h, then cool to room temperature, separate the solid and liquid, collect the fiber, wash it 3 times with deionized water (100ml each time), and then dry it at 70℃ for 6h to obtain magnesium aluminum modified basalt fiber.

[0031] A3: Add 10g of magnesium-aluminum modified basalt fiber to 80g of deionized water, add 0.5g of zirconium oxychloride octahydrate, adjust the pH to 5.0 with 5wt% ammonia, and react at 40℃ for 1.5h; then add 10mL of aqueous solution containing 0.25g of sodium dihydrogen phosphate dropwise over 20min. During the dropwise addition, maintain the pH of the system at 5.0 with 5wt% ammonia or 0.1mol / L hydrochloric acid solution. Continue to react at 40℃ for 1.5h, then separate the solid and liquid, collect the fiber, wash it three times with deionized water (50ml each time), and then add 80g of aqueous solution containing 0.15g of polyethylene glycol (PEG-400) for softening treatment. Impregnate at room temperature for 25min, separate the solid and liquid, collect the fiber, and dry it at 70℃ for 4h to obtain modified basalt fiber.

[0032] Example 3 Preparation of modified basalt fiber A1: Add 10g of basalt fiber to 100mL of anhydrous ethanol and ultrasonically clean for 15min at 30kHz and 200W. Remove the fiber and add it to a sodium hydroxide aqueous solution prepared with 2g of sodium hydroxide and 250g of deionized water. Place the solution in a 50℃ constant temperature water bath and stir at 200rpm for 25min to separate the solid and liquid. Collect the fiber and quickly wash it with 100ml of 0.1wt% acetic acid aqueous solution for 2min, then wash with deionized water until the pH of the washing solution reaches 7.0. Then add the fiber to 150g of anhydrous ethanol and 50% acetic acid aqueous solution. In a mixture of g deionized water, the mixture was stirred and dispersed at 300 rpm for 20 min. Then, 2.5 g of tetraethyl orthosilicate was slowly added dropwise over 15 min. The pH was adjusted to 5.0 using a 5 wt% acetic acid aqueous solution, and the mixture was reacted at 55 °C for 1 h. The pH was then adjusted to 8.6 using 5 wt% ammonia water, and the mixture was reacted at 55 °C for another 1 h. After solid-liquid separation, the fibers were collected, washed twice with anhydrous ethanol (50 mL each time), washed three times with deionized water (50 mL each time), and dried at 70 °C for 4 h to obtain silicon oxide basalt fibers.

[0033] A2: Add 10g of silicon oxide basalt fiber to 300g of deionized water, add 7.0g of magnesium nitrate hexahydrate, 4.0g of aluminum nitrate nonahydrate and 8.0g of urea, stir at 300rpm for 30min; heat to 100℃ and react for 8h, then cool to room temperature, separate solid and liquid, collect the fiber, wash with deionized water 3 times (100ml each time), and then dry at 70℃ for 6h to obtain magnesium aluminum modified basalt fiber.

[0034] A3: Add 10g of magnesium-aluminum modified basalt fiber to 80g of deionized water, add 0.6g of zirconium oxychloride octahydrate, adjust the pH to 5.0 with 5wt% ammonia, and react at 35℃ for 2h; then add 10mL of aqueous solution containing 0.28g of sodium dihydrogen phosphate dropwise over 20min. During the dropwise addition, maintain the pH of the system at 5.0 with 5wt% ammonia or 0.1mol / L hydrochloric acid solution. Continue to react at 35℃ for 2h, then separate the solid and liquid, collect the fiber, wash it three times with deionized water (50ml each time), and then add 80g of aqueous solution containing 0.2g of polyethylene glycol (PEG-400) for softening treatment. Impregnate at room temperature for 20min, separate the solid and liquid, collect the fiber, and dry it at 70℃ for 4h to obtain modified basalt fiber.

[0035] Example 4: Preparation of composite yarn (1) Weigh 130g of cotton fiber and place it in an environment of 23℃ and 65% relative humidity for 24h to balance. Then feed it into an opening machine for opening treatment. The feeding speed is 0.5m / min and the opening roller speed is 600rpm. The opening treatment is performed twice. Then the opened cotton fiber is first subjected to airflow impurity removal treatment. The airflow is clean and dry air with an airflow speed of 6m / s and a treatment time of 3min. Then it is subjected to screen impurity removal treatment. The screen aperture is 2mm and the treatment time is 2min. The impurity removed cotton fiber is then carded into strips by a carding machine. During the carding process, the cylinder speed is 3. The licker-in speed is 30 rpm, the doffer speed is 800 rpm, and the doffer speed is 20 rpm. Then, two drawing processes are performed. Six cotton fiber slivers are fed into the drawing frame together, with a total draft ratio of 6.2, a front roller output speed of 60 m / min, a roller spacing of 42 mm × 45 mm, and a sliver weight of 21 g / 5 m to obtain the first sliver. Six first slivers are fed into the drawing frame together, with a total draft ratio of 6.4, a front roller output speed of 55 m / min, a roller spacing of 42 mm × 45 mm, and a sliver weight of 20 g / 5 m to obtain the finished cotton fiber sliver.

[0036] (2) Weigh 50g of modified basalt fiber (prepared in Example 1) and place it in an environment with a temperature of 23℃ and a relative humidity of 65% for 12h to balance it. Then, load the modified basalt fiber into the fiber unwinding frame and arrange it with a ceramic guide ring and a tension controller. The unwinding speed is 5m / min, the guide tension is 5cN, and the guide angle is 15°, so that the modified basalt fiber is arranged straight, without obvious entanglement, and can be unwound continuously and stably.

[0037] (3) Using the modified basalt fiber from step (2) as the core yarn and the cotton fiber sliver from step (1) as the outer yarn, the core-spun yarn is composited into yarn. During the spinning process, the modified basalt fiber is continuously fed into the middle of the front roller nip. The core yarn feeding speed is consistent with the front roller output speed. The cotton fiber sliver is wrapped around the outside of the modified basalt fiber after being stretched. The stretching ratio is 30 times. The front roller output speed is 12m / min, the spindle speed is 9000r / min, the yarn twist is 750 twists / m, the spinning environment temperature is 23℃, and the relative humidity is 65%. The yarn is formed by twisting the nascent cotton fiber / basalt fiber composite yarn.

[0038] (4) The nascent cotton fiber / basalt fiber composite yarn is wound at a speed of 300 m / min and a tension of 12 cN. It is then set at 80℃ for 30 min and then placed in an environment of 23℃ and 65% relative humidity for 12 h to achieve humidity balance, thus obtaining a high-strength cotton fiber / basalt fiber composite yarn (linear density of 196 tex).

[0039] Example 5: Preparation of Composite Yarn (1) Weigh 150g of cotton fiber and place it in an environment of 23℃ and 65% relative humidity for 24h to balance. Then feed it into an opening machine for opening treatment. The feeding speed is 0.5m / min, the opening roller speed is 600rpm, and the opening treatment is performed twice. Then the opened cotton fiber is first subjected to airflow impurity removal treatment. The airflow is clean and dry air, the airflow speed is 6m / s, and the treatment time is 3min. Then it is subjected to screen impurity removal treatment. The screen aperture is 2mm, and the treatment time is 2min. The impurity removed cotton fiber is then carded into strips by a carding machine. During the carding process, the cylinder speed is 3. The licker-in speed is 30 rpm, the doffer speed is 800 rpm, and the doffer speed is 20 rpm. Then, two drawing processes are performed. Six cotton fiber slivers are fed into the drawing frame together, with a total draft ratio of 6.2, a front roller output speed of 60 m / min, a roller spacing of 42 mm × 45 mm, and a sliver weight of 21 g / 5 m to obtain the first sliver. Six first slivers are fed into the drawing frame together, with a total draft ratio of 6.4, a front roller output speed of 55 m / min, a roller spacing of 42 mm × 45 mm, and a sliver weight of 20 g / 5 m to obtain the finished cotton fiber sliver.

[0040] (2) Weigh 50g of modified basalt fiber (prepared in Example 2) and place it in an environment with a temperature of 23℃ and a relative humidity of 65% for 12h to balance it. Then, load the modified basalt fiber into the fiber unwinding frame and arrange it with a ceramic guide ring and a tension controller. The unwinding speed is 5m / min, the guide tension is 5cN, and the guide angle is 15°, so that the modified basalt fiber is arranged straight, without obvious entanglement, and can be unwound continuously and stably.

[0041] (3) Using the modified basalt fiber from step (2) as the core yarn and the cotton fiber sliver from step (1) as the outer yarn, the core-spun yarn is composited into yarn. During the spinning process, the modified basalt fiber is continuously fed into the middle of the front roller nip. The core yarn feeding speed is consistent with the front roller output speed. The cotton fiber sliver is wrapped around the outside of the modified basalt fiber after being stretched. The stretching ratio is 30 times. The front roller output speed is 12m / min, the spindle speed is 9000r / min, the yarn twist is 750 twists / m, the spinning environment temperature is 23℃, and the relative humidity is 65%. The yarn is formed by twisting the nascent cotton fiber / basalt fiber composite yarn.

[0042] (4) The nascent cotton fiber / basalt fiber composite yarn is wound at a speed of 300 m / min and a tension of 12 cN. It is then set at 80℃ for 30 min and then placed in an environment of 23℃ and 65% relative humidity for 12 h to achieve humidity balance, thus obtaining a high-strength cotton fiber / basalt fiber composite yarn (linear density of 198 tex).

[0043] Example 6 Preparation of composite yarn (1) Weigh 180g of cotton fiber and place it in an environment of 23℃ and 65% relative humidity for 24h to balance. Then feed it into an opening machine for opening treatment. The feeding speed is 0.5m / min and the opening roller speed is 600rpm. The opening treatment is performed twice. Then the opened cotton fiber is first subjected to airflow impurity removal treatment. The airflow is clean and dry air with an airflow speed of 6m / s and a treatment time of 3min. Then it is subjected to screen impurity removal treatment. The screen aperture is 2mm and the treatment time is 2min. The impurity removed cotton fiber is then carded into strips by a carding machine. During the carding process, the cylinder speed is 3. The licker-in speed is 30 rpm, the doffer speed is 800 rpm, and the doffer speed is 20 rpm. Then, two drawing processes are performed. Six cotton fiber slivers are fed into the drawing frame together, with a total draft ratio of 6.2, a front roller output speed of 60 m / min, a roller spacing of 42 mm × 45 mm, and a sliver weight of 21 g / 5 m to obtain the first sliver. Six first slivers are fed into the drawing frame together, with a total draft ratio of 6.4, a front roller output speed of 55 m / min, a roller spacing of 42 mm × 45 mm, and a sliver weight of 20 g / 5 m to obtain the finished cotton fiber sliver.

[0044] (2) Weigh 50g of modified basalt fiber (prepared in Example 3) and place it in an environment with a temperature of 23℃ and a relative humidity of 65% for 12h to balance it. Then, load the modified basalt fiber into the fiber unwinding frame and arrange it with a ceramic guide ring and a tension controller. The unwinding speed is 5m / min, the guide tension is 5cN, and the guide angle is 15°, so that the modified basalt fiber is arranged straight, without obvious entanglement, and can be unwound continuously and stably.

[0045] (3) Using the modified basalt fiber from step (2) as the core yarn and the cotton fiber sliver from step (1) as the outer yarn, the core-spun yarn is composited into yarn. During the spinning process, the modified basalt fiber is continuously fed into the middle of the front roller nip. The core yarn feeding speed is consistent with the front roller output speed. The cotton fiber sliver is wrapped around the outside of the modified basalt fiber after being stretched. The stretching ratio is 30 times. The front roller output speed is 12m / min, the spindle speed is 9000r / min, the yarn twist is 750 twists / m, the spinning environment temperature is 23℃, and the relative humidity is 65%. The yarn is formed by twisting the nascent cotton fiber / basalt fiber composite yarn.

[0046] (4) The nascent cotton fiber / basalt fiber composite yarn is wound at a speed of 300 m / min and a tension of 12 cN. Then it is set at 80℃ for 30 min and then placed in an environment of 23℃ and 65% relative humidity for 12 h to achieve humidity balance, thus obtaining a high-strength cotton fiber / basalt fiber composite yarn (linear density of 202 tex).

[0047] Comparative Example 1 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A1, the amount of tetraethyl orthosilicate added is replaced with 4.0g.

[0048] Comparative Example 2 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A1, the amount of tetraethyl orthosilicate added is replaced with 0.5g.

[0049] Comparative Example 3 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A1, tetraethyl orthosilicate is replaced with an equal weight of methyltrimethoxysilane.

[0050] Comparative Example 4 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A2, the amount of magnesium nitrate hexahydrate added is replaced with 2.0g.

[0051] Comparative Example 5 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A2, urea is replaced with an equal weight of N-methylurea.

[0052] Comparative Example 6 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A3, sodium dihydrogen phosphate is replaced with an equal weight of disodium hydrogen phosphate.

[0053] Comparative Example 7 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A3, polyethylene glycol PEG-400 is replaced with an equal weight of polyethylene glycol PEG-1000.

[0054] Comparative Example 8 The raw material composition and preparation method of the composite yarn are basically the same as in Example 5, except that the modified basalt fiber used in the preparation of the composite yarn is replaced with an equal weight of modified basalt fiber prepared by the following method: The preparation method of modified basalt fiber is basically the same as that in Example 2, except that in step A3, polyethylene glycol PEG-400 is replaced with an equal weight of polyethylene glycol PEG-200.

[0055] The cotton fibers used in the embodiments and comparative examples of this application have a fineness of 1.6 dtex and a length of 36 mm; the basalt fibers are basalt fiber twisted yarns with an average single filament diameter of 10 μm and a linear density of 66 tex, and are produced by Beihai Fiberglass Co., Ltd. in China.

[0056] Unless otherwise stated, all pH adjustment and maintenance operations in this invention are based on the target pH value set in the steps, and the pH of the system is controlled within ±0.2.

[0057] The composite yarns prepared in the examples and comparative examples were tested for breaking strength, breaking elongation, abrasion resistance, hairiness index, and interfacial cohesion. The test results are shown in Table 1.

[0058] Before testing, the high-strength cotton fiber / basalt fiber composite yarns prepared in the examples and comparative examples were placed in a standard environment of 20±2℃ and 65±4% relative humidity for 24 hours for equilibration, and then the performance was tested.

[0059] Tensile strength and elongation at break were tested according to Method A of GB / T 3916-2013 "Determination of tensile strength and elongation at break of single yarn in packaged textiles (CRE method)". An electronic universal testing machine was used with a clamping distance of 500 mm, a tensile speed of 500 mm / min, and a pretension determined according to the yarn linear density (0.5 cN / tex). Ten yarns were tested for each sample, and the tensile strength and elongation at break were recorded, with the average value taken.

[0060] Abrasion resistance test: The test was conducted using a yarn abrasion tester. The composite yarn was brought into contact with 600-mesh alumina sandpaper under a tension of 0.5 cN / tex. The effective contact length between the yarn and the sandpaper was 30 mm. The sandpaper was fixed on the reciprocating friction table, and the yarn was in contact with the sandpaper surface along its length. The friction stroke was 30 mm, the friction frequency was 60 times / min, and the applied load was 20 cN. The number of friction cycles before the yarn broke was recorded. Each sample was tested 10 times, and the sandpaper was replaced after each yarn test. The average value was taken.

[0061] Hairiness index test: The yarn hairiness tester is used for testing. The composite yarn passes through the test area at a speed of 30m / min and the test length is 100m. During the test, the yarn tension is controlled at 0.25cN / tex. The number of hairs with a length greater than 3mm protruding from the yarn surface is recorded and recorded as H3. Each sample is tested 5 times and the average value is taken (rounded to the nearest integer).

[0062] Interface cohesion test: Take a 100mm long composite yarn sample. Under a microscope, gently peel off the outer cotton fiber layer from one end of the sample, exposing 20mm of the modified basalt fiber core filament. Keep the cotton fiber outer layer intact for the remaining 80mm, which is the effective pull-out section. Fix the exposed modified basalt fiber core filament to the upper clamp and fix the unpeeled outer cotton fiber layer to the lower clamp. The clamping surfaces are treated with rubber pads for anti-slip to prevent slippage during the test. After applying a pretension of 1cN, perform the pull-out test at a speed of 20mm / min and record the maximum pull-out force. Test each sample 10 times and take the average value.

[0063] Table 1. Test Data of Composite Yarn Performance In Comparative Example 1, the excessive amount of tetraethyl orthosilicate resulted in an overly thick, hard, and brittle silicon oxide layer on the basalt fiber surface, reducing the flexibility of the core filament and the uniformity of subsequent modification layer deposition. In Comparative Example 2, the excessive amount of tetraethyl orthosilicate may have led to an incomplete silicon oxide layer, insufficient surface hydroxyl groups, micro-roughness, and a weak foundation for the adhesion of inorganic modification layers. In Comparative Example 3, methyltrimethoxysilane was used instead of tetraethyl orthosilicate, introducing hydrophobic methyl groups, which reduced polar binding sites and weakened the synergistic anchoring effect of the subsequent magnesium-aluminum layer and zirconium phosphate layer. Therefore, the mechanical interlocking, polar bonding, and frictional resistance between the core filament and the outer cotton fiber in Comparative Examples 1-3 were all weaker than in the examples.

[0064] In Comparative Example 4, the reduced amount of magnesium nitrate hexahydrate resulted in insufficient magnesium source, leading to a decrease in the amount and continuity of the magnesium-aluminum deposition layer, and insufficient inorganic support, rough structure, and polar sites on the fiber surface. In Comparative Example 5, the replacement of urea with N-methylurea altered the slow-release alkali behavior of the system, reducing the uniformity of magnesium and aluminum ion deposition on the fiber surface and making it prone to localized insufficient deposition or granular deposition. These defects weaken the bonding stability between the cotton fiber outer sheath and the modified basalt core fiber, affecting the load-bearing effect of the subsequent zirconium phosphate layer. This makes the composite yarn more prone to outer sheath loosening and interfacial slippage during stretching and friction, resulting in lower strength, abrasion resistance, and interfacial cohesion compared to the examples.

[0065] In Comparative Example 6, after sodium dihydrogen phosphate was replaced with disodium hydrogen phosphate, the phosphate species and local acid-base environment changed. Zirconium phosphate was prone to rapid deposition or agglomeration, making it difficult to form a uniform and stable anchoring structure on the surface of the magnesium-aluminum modified layer. This weakened the polar bonding, inorganic locking and interfacial friction on the core filament surface, resulting in a decrease in the cohesion stability between the outer cotton fiber and the basalt core filament, leading to a decrease in breaking strength, number of frictions and interfacial cohesion, and an increase in the hairiness index.

[0066] In Comparative Example 7, PEG-400 was replaced with PEG-1000, which has a longer molecular chain and tends to form a thicker lubricating layer on the fiber surface. Although this increases the elongation at break, it weakens the direct frictional engagement between the core filament and the outer cotton fiber. In Comparative Example 8, PEG-400 was replaced with PEG-200, which has a lower molecular weight and shorter chain segments. This results in insufficient softening, wetting, and stress buffering effects on the fiber surface, leading to reduced adhesion between the core filament and the cotton fiber. Therefore, both excessively high and excessively low PEG molecular weights are detrimental to the formation of a moderately flexible interfacial transition layer, resulting in reduced abrasion resistance, interfacial cohesion, and breaking strength, and increased hairiness index in Comparative Examples 7-8.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A high-strength cotton fiber / basalt fiber composite yarn, characterized in that, The composite yarn includes modified basalt fibers as the core layer and cotton fibers covering the outside of the modified basalt fibers. The modified basalt fiber is prepared by the following method: A1: Basalt fibers are subjected to alkaline hydroxylation treatment under the action of sodium hydroxide, and then hydrolyzed and condensed with tetraethyl orthosilicate to obtain silicon oxide basalt fibers. A2: Silica basalt fibers react with magnesium salts, aluminum salts and urea to obtain magnesium-aluminum modified basalt fibers; A3: Magnesium-aluminum modified basalt fibers react with zirconium salts, then with phosphates, and are softened by polyethylene glycol to obtain modified basalt fibers.

2. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, In step A1, the mass ratio of basalt fiber, sodium hydroxide and tetraethyl orthosilicate is 10:(1-2):(1-2.5).

3. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, In step A2, the mass ratio of the silicon oxide basalt fiber, magnesium salt, aluminum salt and urea is 10:(3-7):(2-4):(4-8).

4. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, In step A3, the mass ratio of the magnesium-aluminum modified basalt fiber, zirconium salt, phosphate and polyethylene glycol is 100:(4-6):(2-2.8):(1-2).

5. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, In step A2, the magnesium salt is magnesium nitrate hexahydrate, and the aluminum salt is aluminum nitrate nonahydrate.

6. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, In step A3, the zirconium salt is zirconium oxychloride octahydrate.

7. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, In step A3, the phosphate is sodium dihydrogen phosphate.

8. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, In step A3, the polyethylene glycol is PEG-400.

9. The high-strength cotton fiber / basalt fiber composite yarn according to claim 1, characterized in that, The mass ratio of the modified basalt fiber to the cotton fiber is 5:(13-18).

10. A method for preparing the high-strength cotton fiber / basalt fiber composite yarn according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Cotton fibers are subjected to moisture conditioning, opening, impurity removal, carding and drawing to obtain sliver cotton fibers; (2) After the modified basalt fiber is conditioned and balanced, it is unwound and finished. (3) Using modified basalt fiber as the core yarn and cotton fiber sliver as the outer yarn, the core-spun yarn is composite yarn is produced by core-spun yarn process, so that the cotton fiber is wrapped on the outside of the modified basalt fiber to obtain nascent cotton fiber / basalt fiber composite yarn. (4) The nascent cotton fiber / basalt fiber composite yarn is wound and shaped to obtain a high-strength cotton fiber / basalt fiber composite yarn.

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