Preparation method of roving strip core-wrapped impact-resistant composite yarn and composite yarn

Abstract

The invention relates to a preparation method of a roving strip core-wrapped impact-resistant composite yarn and the composite yarn, and the method comprises the following steps: 1, loading a shear hardening adhesive on a roving, and drying to obtain a composite roving; step 2, carrying out rolling treatment on the composite roving to obtain a functional roving strip; 3, taking a high-performance fiber filament as a core yarn, and sequentially wrapping the two functional roving slivers on the surface of the high-performance fiber filament in opposite twisting directions and the same twisting degree to obtain the roving sliver core-wrapped impact-resistant composite yarn; the composite yarn comprises a high-performance fiber filament serving as a core yarn and a coating layer, the coating layer comprises two functional roving strips, and the functional roving strips are prepared by dipping roving in shear hardening glue and then rolling the roving; wherein one functional roving strip is wound on the surface of the high-performance fiber filament, and the other functional roving strip is wound on the outer surface of the previous functional roving strip in an opposite twisting direction. Therefore, the design has better stability of shock resistance.

Description

Technical Field

[0001] This invention relates to a method for preparing composite yarn and the composite yarn itself, belonging to the field of spinning technology, and particularly to a method for preparing a roving-wrapped core-type impact-resistant composite yarn and the composite yarn itself. Background Technology

[0002] In fields such as sports equipment, industrial production, emergency rescue, and packaging and transportation, the demand for high-impact protective materials is becoming increasingly urgent. Although traditional materials such as ceramic, metal, and fiber resin composite boards have good impact resistance, they have problems such as high rigidity, heavy weight, poor flexibility, and easy cracking, making it difficult to meet the application requirements of lightweight and flexible materials.

[0003] To address the lack of flexibility in traditional protective materials, high-strength, high-modulus fibers such as aramid and ultra-high molecular weight polyethylene are typically used to prepare impact-resistant yarns. These fibers possess both excellent mechanical properties and a certain degree of flexibility. However, the simple twisting of single or multiple fibers can easily lead to stress concentration when subjected to impact, causing the yarn to split or break, making it difficult to achieve an effective balance between flexibility and impact resistance.

[0004] To further enhance impact resistance, shear thickening fluids or shear hardening adhesives are typically introduced into yarn systems. This allows the material to rapidly transition from a flexible to a rigid state under instantaneous high-speed impact to dissipate energy, and then return to its soft state after the external force is removed, achieving a synergy between impact resistance and comfort. However, when materials such as shear thickening fluids and shear hardening adhesives are combined with traditional yarns, problems such as uneven distribution, weak bonding, and even leakage are common, resulting in poor stability of impact resistance.

[0005] Chinese patent application No. 202211661661.X, filed on December 23, 2022, discloses a fluid flexible linear material, its composite yarn forming method, and its application. The fluid flexible linear material is a core-sheath composite structure, comprising a fluid material as a core layer, a thin film layer encapsulating the fluid material, and a flexible strip as a sheath layer that wraps around and holds the thin film layer. While this patent solves the problem of fluids being unable to be combed and drawn into yarn, it still has the following drawbacks:

[0006] This design relies on a thin film layer to physically encapsulate the liquid material. The thin film layer is only bonded to the liquid and the external fiber strips at the interface. Under long-term use or repeated impact, it is prone to peeling and breakage, resulting in media leakage and interlayer separation, which still leads to poor stability of impact resistance.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this patent application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to overcome the defects and problems of poor stability of impact resistance in the prior art, and to provide a method for preparing a core-wrapped roving impact-resistant composite yarn with better stability of impact resistance, as well as the composite yarn itself.

[0009] To achieve the above objectives, the technical solution of the present invention is: a method for preparing a roving-wrapped core-type impact-resistant composite yarn and the composite yarn, the method comprising the following steps:

[0010] Step 1: First, mix and stir the shear-hardening adhesive with a volatile organic solvent to obtain a shear-hardening adhesive dispersion; then, immerse the roving in the shear-hardening adhesive dispersion and sonicate it at room temperature until the roving is coated with a white colloid to obtain modified roving; then, dry the modified roving at room temperature to obtain composite roving.

[0011] Step 2: Roller pressing the above-mentioned composite roving to obtain functional roving strips;

[0012] Step 3: Using high-performance fiber filament as the core yarn, two of the above-mentioned functional rovings are wrapped sequentially around the surface of the high-performance fiber filament with opposite twist directions and the same twist, to obtain a core-wrapped roving anti-impact composite yarn.

[0013] In the first step, the solid-liquid ratio of the shear-hardening adhesive to the volatile organic solvent in the shear-hardening adhesive dispersion is 0.3g-1g:1ml;

[0014] In the first step, the fineness of the roving is 200tex-800tex;

[0015] In the third step, the fineness of the high-performance fiber filament is 100D-600D.

[0016] In the first step, the volatile organic solvent is any one or a combination of anhydrous ethanol and acetone.

[0017] In the first step, immersing the roving in the shear-hardening adhesive dispersion and ultrasonically treating it at room temperature until the roving is coated with a white colloid to obtain modified roving refers to:

[0018] First, the roving is immersed in the shear-hardening adhesive dispersion and then subjected to ultrasonic treatment at room temperature. The ultrasonic power of the ultrasonic treatment is 50W-300W, and the ultrasonic treatment lasts for 20min-40min to obtain the modified roving.

[0019] In the second step, the rolling process is achieved by a rolling device, which includes an input guide rod, an output gear, a pressure roller, a telescopic spring component, an output guide rod, and a winding mechanism.

[0020] The input guide rod, the output gear, and the output guide rod are all aligned.

[0021] The pressure roller is located directly above the output gear, and the pressure roller and the output gear are arranged vertically opposite each other; a roller gap is formed between the pressure roller and the output gear to allow the composite roving to pass through.

[0022] The top of the pressure roller is connected to the bottom of the telescopic spring component;

[0023] The input guide rod is located on the inlet side of the roll gap, and the input guide rod introduces the composite roving into the roll gap; the output guide rod is located on the outlet side of the roll gap, and the output guide rod guides the functional roving strip after roll processing to the winding mechanism.

[0024] In the second step, the rolling pressure of the rolling process is 1MPa-5MPa, and the rolling output speed is 5r / min-20r / min;

[0025] In the second step, the functional roving is a flat strip; the thickness of the functional roving is 0.3mm-1.2mm, and the width of the functional roving is 5mm-10mm.

[0026] In the third step, the step of using high-performance fiber filaments as core yarn and sequentially wrapping two of the aforementioned functional rovings with opposite twist directions and the same twist degree around the surface of the high-performance fiber filaments means:

[0027] Using high-performance fiber filaments as the core yarn, a hollow spindle wrapping device is used to wrap two of the above-mentioned functional rovings sequentially around the surface of the high-performance fiber filaments with opposite twist directions and the same twist. During wrapping, the spindle speed is 2000rpm-6000rpm and the twist is 200tw / cm-1000tw / cm.

[0028] In the third step, the high-performance fiber filament is any one or any combination of aramid 1414 fiber, PBO fiber, ultra-high molecular weight polyethylene fiber, and polyimide fiber.

[0029] The composite yarn is prepared by the method of preparing a roving core-wrapped impact-resistant composite yarn according to any one of claims 1-8;

[0030] The composite yarn includes high-performance fiber filaments and a covering layer;

[0031] The high-performance fiber filament is a core yarn;

[0032] The coating layer includes two functional roving strips, which are made by impregnating roving with shear hardening adhesive and then rolling.

[0033] One of the functional rovings is wrapped around the surface of the high-performance fiber filament, and the other functional roving is wrapped around the outer surface of the first functional roving with opposite twist; the two functional rovings have the same twist.

[0034] The mass of the shear-hardening adhesive loaded on the functional roving accounts for more than 70% of the total mass of the functional roving.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. This invention discloses a method for preparing a core-wound roving-type impact-resistant composite yarn and the composite yarn. The method includes: firstly, mixing and stirring a shear-hardening adhesive with a volatile organic solvent to obtain a shear-hardening adhesive dispersion; immersing roving in the shear-hardening adhesive dispersion for ultrasonic treatment until the roving is coated with a white colloid to obtain modified roving; then, drying the modified roving at room temperature to obtain composite roving; further, rolling the composite roving to obtain a functional roving strip; finally, using a high-performance fiber filament as the core yarn, sequentially wrapping two functional roving strips with opposite twist directions and the same twist onto the surface of the high-performance fiber filament to obtain a core-wound roving-type impact-resistant composite yarn. The advantages of this invention also include:

[0037] Firstly, roving, as a multi-fiber bundle aggregate, possesses excellent media adsorption capacity due to its high bulkiness and rich pore structure. Using roving as a carrier to carry shear hardening adhesive, and through ultrasonic-assisted impregnation, the shear hardening adhesive is fully and uniformly penetrated and anchored in the three-dimensional fiber network of the roving, ensuring the homogeneity of the functional media distribution from the source and guaranteeing stable and reliable impact resistance at the material level.

[0038] Secondly, the roving with shear-hardening adhesive is rolled into functional roving strips through a rolling process, forming a nested and firmly interlocked composite between the shear-hardening adhesive and the roving fibers. In this composite, the dense fiber network creates a spatial confinement effect for the shear-hardening adhesive, while the mechanical anchoring between the fibers and the adhesive effectively inhibits the macroscopic migration and exudation of the adhesive. This structurally solves the cold flow problem of the shear-hardening adhesive and achieves long-term stable fixation of the functional medium. Tests show that the composite yarn prepared by this invention has a 2%-8% lower impact force dissipation rate after 60 days of rest compared to the initial value, proving its long-term stability.

[0039] Thirdly, upon impact, the shear-hardening adhesive in the composite instantly hardens, converting kinetic energy into frictional heat. Simultaneously, the roving fibers are stretched and rub against each other. The two work together to form a multi-stage energy dissipation mechanism of "instantaneous hardening of the adhesive" and "fiber friction stretching," significantly improving the energy absorption efficiency of a single impact. At the same time, the robust fiber-colloid interface structure effectively resists media migration and interface delamination caused by repeated impacts, enabling the yarn to maintain stable impact resistance after multiple impacts. The results of 100 consecutive impact tests show that the impact force dissipation rate of the composite yarn of this invention is only reduced by 2%-10% compared to the initial value, fundamentally suppressing performance degradation.

[0040] Fourthly, the two-way wrapping structure with opposite twist directions and the same twist degree is adopted, so that the two functional rovings are symmetrically wrapped on the surface of the core yarn. This structure eliminates the untwisting and stress concentration that are easy to occur in unidirectional wrapping, and avoids the risk of reduced stability caused by this. At the same time, it makes the yarn evenly stressed, effectively prevents the decline in impact resistance caused by unilateral wear, and further enhances the overall structural stability of the yarn.

[0041] Therefore, the present invention not only has impact resistance, but also good stability of impact resistance.

[0042] 2. The present invention discloses a method for preparing a core-wrapped roving-type impact-resistant composite yarn and the composite yarn thereof. The yarn comprises high-performance fiber filaments and a covering layer. The high-performance fiber filaments are the core yarn, and the covering layer comprises two functional rovings. The functional rovings are obtained by impregnating roving with a shear-hardening adhesive and then rolling. One functional roving is wrapped around the surface of the high-performance fiber filament, and the other functional roving is wrapped around the outer surface of the first functional roving with opposite twist. The twist of the two functional rovings is consistent. In application, the yarn of the present invention is made into a protective fabric. When subjected to a sudden high-speed impact, the shear-hardening adhesive in the functional roving directly wrapped around the core yarn hardens and dissipates energy first. When the impact energy is transferred to the other functional roving in the outer layer, the shear-hardening adhesive hardens and dissipates energy again. Simultaneously, the roving fibers in the two functional rovings are stretched and rub against each other, forming a multi-level synergistic energy dissipation mechanism. The high-performance fiber filaments maintain structural integrity during the impact process, providing stable support for the entire energy dissipation process. The advantages of the present invention also include:

[0043] First, the multi-fiber bundle structure of the roving provides a large number of adhesion points for the shear-hardening adhesive. By impregnation, the adhesive is loaded into the roving fiber network. The shear-hardening adhesive load on the functional roving strip is high, which lays the material basis for efficient energy consumption.

[0044] Secondly, the bidirectional symmetrical wrapping structure not only increases the overall content of shear hardening adhesive in the yarn, but also fully leverages the synergistic advantages of the high strength characteristics of high-performance fibers and the impact energy dissipation characteristics of shear hardening adhesive; actual tests show that the yarn of this invention has a single impact energy dissipation rate of 68%-85%, and its initial impact resistance performance is superior.

[0045] Therefore, the present invention not only has good stability of impact resistance, but also improves impact resistance.

[0046] 3. In the preparation method of the roving-wrapped core-type impact-resistant composite yarn of the present invention, and in the composite yarn, the high-performance fiber filament is any one or any combination of aramid 1414 fiber, PBO fiber, ultra-high molecular weight polyethylene fiber, and polyimide fiber. In application, the high-performance fiber filament serves as the core yarn. Due to its high strength and high modulus properties, it maintains its structural integrity during impact, preventing yarn breakage or excessive deformation, and providing stable mechanical support for the entire energy-consuming process. Under normal use, the high-performance fiber filament provides excellent basic mechanical properties to the yarn, significantly improving its strength and abrasion resistance. Therefore, the present invention not only improves impact resistance but also enhances the mechanical properties of the yarn.

[0047] 4. The present invention discloses a method for preparing a roving-wrapped core-type impact-resistant composite yarn and the composite yarn thereof. Only three steps—impregnation, rolling, and wrapping—are required to obtain the roving-wrapped core-type impact-resistant composite yarn. Compared to existing technologies, this invention utilizes the multi-fiber bundle structure of the roving itself to adsorb and fix the shear-hardening adhesive, eliminating the need for freeze-curing of the functional medium or independent physical encapsulation. Furthermore, the densification and firm fixation of the functional medium are achieved through rolling, avoiding complex processes such as multiple coatings and thermal stretching, significantly shortening the manufacturing process and improving efficiency. Therefore, this invention not only improves the mechanical properties of the yarn but also shortens the manufacturing process. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the rolling process in this invention.

[0049] Figure 2 This is a schematic diagram of the composite yarn structure in this invention.

[0050] Figure 3 This is a schematic diagram of the process of composite yarn being wrapped into yarn in this invention.

[0051] Figure 4 This is a graph showing the test results of the impact resistance of the fabric prepared by the composite yarn in Example 13 of the present invention.

[0052] Figure 5 This is a graph showing the impact stability test results of the fabric prepared by the composite yarn in Example 14 of the present invention.

[0053] Figure 6 This is a graph showing the impact resistance and durability test results of the fabric prepared by the composite yarn in Example 15 of the present invention.

[0054] In the diagram: 1. Composite roving; 11. Functional roving strip; 2. Covering layer; 3. High-performance fiber filament; 4. Roller pressing device; 41. Input guide rod; 5. Output gear; 51. Roller pressing gap; 6. Pressure roller; 7. Telescopic spring component; 71. Adjusting nut; 72. Spring; 73. Pressure block; 74. Pressure arm; 75. Screw; 8. Output guide rod; 9. Winding mechanism; 10. Hollow spindle covering device; 10. Feeding mechanism; 101. Feeding roller; 102. Tensioner; 103. Feeding guide rod; 104. Lower hollow spindle; 105. Upper hollow spindle; 106. Lower air ring ceramic component; 107. Upper air ring ceramic component; 108. Output mechanism; 109. Output roller; 110. Output guide rod; 111. Lateral winding mechanism; 112. Upper hollow spindle yarn tube; 113. Lower hollow spindle yarn tube; 114. Spindle; 115. Detailed Implementation

[0055] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] See Figures 1-6 A method for preparing a roving-wrapped core-type impact-resistant composite yarn and the composite yarn thereof, the method comprising the following steps:

[0057] Step 1: First, mix and stir the shear hardening adhesive with a volatile organic solvent to obtain a shear hardening adhesive dispersion; then, immerse the roving in the shear hardening adhesive dispersion and sonicate it at room temperature until the roving is coated with a white colloid to obtain modified roving; then, dry the modified roving at room temperature to obtain composite roving 1.

[0058] Step 2: Roll the composite roving 1 to obtain the functional roving strip 11;

[0059] Step 3: Using the high-performance fiber filament 3 as the core yarn, two of the above-mentioned functional rovings 11 are wrapped around the surface of the high-performance fiber filament 3 in opposite directions and with the same twist, to obtain a roving core-wrapped impact-resistant composite yarn.

[0060] In the first step, the solid-liquid ratio of the shear-hardening adhesive to the volatile organic solvent in the shear-hardening adhesive dispersion is 0.3g-1g:1ml;

[0061] In the first step, the fineness of the roving is 200tex-800tex;

[0062] In the third step, the fineness of the high-performance fiber filament 3 is 100D-600D.

[0063] In the first step, the volatile organic solvent is any one or a combination of anhydrous ethanol and acetone.

[0064] In the first step, immersing the roving in the shear-hardening adhesive dispersion and ultrasonically treating it at room temperature until the roving is coated with a white colloid to obtain modified roving refers to:

[0065] First, the roving is immersed in the shear-hardening adhesive dispersion and then subjected to ultrasonic treatment at room temperature. The ultrasonic power of the ultrasonic treatment is 50W-300W, and the ultrasonic treatment lasts for 20min-40min to obtain the modified roving.

[0066] In the second step, the rolling process is achieved by the rolling device 4, which includes an input guide rod 41, an output gear 5, a pressure roller 6, a telescopic spring component 7, an output guide rod 8, and a winding mechanism 9.

[0067] The input guide rod 41, the output gear 5, and the output guide rod 8 are aligned.

[0068] The pressure roller 6 is located directly above the output gear 5, and the pressure roller 6 and the output gear 5 are arranged vertically opposite each other; a roller gap 51 is formed between the pressure roller 6 and the output gear 5 to allow the composite roving 1 to pass through.

[0069] The top of the pressure roller 6 is connected to the bottom of the telescopic spring component 7;

[0070] The input guide rod 41 is located on the inlet side of the roller pressing gap 51, and the input guide rod 41 introduces the composite roving 1 into the roller pressing gap 51; the output guide rod 8 is located on the outlet side of the roller pressing gap 51, and the output guide rod 8 guides the functional roving sliver 11 after roller pressing to the winding mechanism 9.

[0071] In the second step, the rolling pressure of the rolling process is 1MPa-5MPa, and the rolling output speed is 5r / min-20r / min;

[0072] In the second step, the functional roving 11 is a flat strip; the thickness of the functional roving 11 is 0.3mm-1.2mm, and the width of the functional roving 11 is 5mm-10mm.

[0073] In the third step, the step of using the high-performance fiber filament 3 as the core yarn and wrapping the two aforementioned functional rovings 11 sequentially around the surface of the high-performance fiber filament 3 with opposite twist directions and the same twist means:

[0074] Using high-performance fiber filament 3 as the core yarn, a hollow spindle wrapping device 10 is used to wrap two of the above-mentioned functional rovings 11 sequentially around the surface of the high-performance fiber filament 3 with opposite twist directions and the same twist. During wrapping, the spindle speed is 2000rpm-6000rpm and the twist is 200 twists / cm-1000 twists / cm.

[0075] In the third step, the high-performance fiber filament 3 is any one or any combination of aramid 1414 fiber, PBO fiber, ultra-high molecular weight polyethylene fiber, and polyimide fiber.

[0076] The composite yarn is prepared by the method of preparing a roving core-wrapped impact-resistant composite yarn according to any one of claims 1-8;

[0077] The composite yarn comprises high-performance fiber filaments 3 and a covering layer 2;

[0078] The high-performance fiber filament 3 is the core yarn;

[0079] The covering layer 2 includes two functional roving strips 11, which are made by impregnating roving with shear hardening adhesive and then rolling.

[0080] One of the functional rovings 11 is wrapped around the surface of the high-performance fiber filament 3, and the other functional roving 11 is wrapped around the outer surface of the first functional roving 11 with opposite twist; the twist of the two functional rovings 11 is the same.

[0081] The mass of the shear-hardening adhesive loaded on the functional roving 11 accounts for more than 70% of the total mass of the functional roving 11.

[0082] The following are supplementary descriptions of the present invention:

[0083] In the first step of this invention, the roving refers to a continuous cylindrical multi-fiber bundle assembly formed by first opening, combing, and drawing the fiber raw material, and then stretching the fiber roving on a roving frame and applying low twist. The low twist is only used to give the fiber roving the necessary bundled properties to ensure that the roving maintains its structural integrity during impregnation and wrapping, while not affecting the penetration and adhesion of the shear hardening adhesive.

[0084] Preferably, in the first step of this invention, the roving is any one or any combination of cotton roving, polyester roving, wool roving, linen roving, viscose roving, aramid 1313 roving, polyimide roving, and viscose / aramid roving. Among them, natural fiber roving and synthetic fiber rovings such as aramid 1313, polyimide, and viscose / aramid contain active groups such as hydroxyl, amide, and imide bonds, which can form hydrogen bonds with shear-hardening adhesives, thereby enhancing the interfacial bonding strength between the two. Although polyester roving does not have active groups, as a common chemical fiber material, it has the advantages of low cost and easy market availability.

[0085] In the first step of this invention, the shear-hardening adhesive is a polyborosiloxane material; it is formed by the dehydration condensation of hydroxyl silicone oil with boron-oxygen backbone and boron source material (such as boric acid) at high temperature. The dynamic BO bonds in its molecular structure enable it to harden and dissipate energy rapidly when subjected to high-speed impact, and restore its softness after the external force is removed, thus possessing both protective properties and flexibility.

[0086] In the first step of this invention, drying the modified roving at room temperature to obtain composite roving 1 means: letting the modified roving stand and dry at room temperature until the volatile organic solvents on the surface and inside of the modified roving are completely evaporated, thus obtaining composite roving 1; complete evaporation means that there is no obvious dampness when touching the surface and inside of the modified roving.

[0087] The hollow ingot coating device 10 described in this invention is the HKV141D hollow ingot coating device from Zhejiang Jinggong Technology Co., Ltd.

[0088] The room temperature described in this invention is 20℃-30℃; preferably, the room temperature is 25℃.

[0089] The bidirectional wrapping structure of this invention adopts a design with opposite twist directions and the same twist: after the first functional roving 11 is wrapped around the surface of the core yarn, the second functional roving 11 is wrapped around the outer surface of the first yarn with opposite twist directions, forming a mutually locking symmetrical structure that effectively prevents untwisting and slippage; at the same time, the wrapping of the first functional roving 11 changes the surface of the core yarn from smooth to rough, providing a better bonding interface for the wrapping of the second functional roving 11; in addition, the functional roving 11 after roll pressing is flat and strip-shaped, which significantly increases the wrapping contact area and further enhances the friction and mechanical locking effect; therefore, this invention can maintain structural stability under repeated stress or impact conditions, fundamentally avoiding the risk of slippage.

[0090] Example 1:

[0091] See Figures 1-6 A method for preparing a roving-wrapped core-type impact-resistant composite yarn and the composite yarn thereof, the method comprising the following steps:

[0092] Step 1: First, mix and stir the shear hardening adhesive with a volatile organic solvent to obtain a shear hardening adhesive dispersion; then, immerse the roving in the shear hardening adhesive dispersion and sonicate it at room temperature until the roving is coated with a white colloid to obtain modified roving; then, dry the modified roving at room temperature to obtain composite roving 1.

[0093] Step 2: Roll the composite roving 1 to obtain the functional roving strip 11;

[0094] Step 3: Using the high-performance fiber filament 3 as the core yarn, two of the above-mentioned functional rovings 11 are wrapped around the surface of the high-performance fiber filament 3 in opposite directions and with the same twist, to obtain a roving core-wrapped impact-resistant composite yarn.

[0095] Example 2:

[0096] The basic content is the same as in Example 1, except that: in the first step, the solid-liquid ratio of the shear hardening adhesive to the volatile organic solvent in the shear hardening adhesive dispersion is 0.3g-1g:1ml; in the first step, the fineness of the roving is 200tex-800tex; and in the third step, the fineness of the high-performance fiber filament 3 is 100D-600D.

[0097] In application, the solid-liquid ratio of the shear-hardening adhesive dispersion determines the loading amount and distribution uniformity of the shear-hardening adhesive on the roving after impregnation. If the solid-liquid ratio is too low (<0.3g:1ml), the shear-hardening adhesive content is too low, resulting in insufficient adhesive adhering to the roving after impregnation. This makes it difficult to form a continuous and complete energy-dissipating layer in the roving fiber network, leading to a significant decrease in the yarn's impact resistance. If the solid-liquid ratio is too high (>1g:1ml), the dispersion concentration is too high, and the shear-hardening adhesive is prone to agglomeration or local enrichment during roving impregnation. This makes it difficult to penetrate and anchor uniformly in the three-dimensional fiber network of the roving, resulting in uneven adhesive distribution and affecting the stability of impact resistance. Therefore, a ratio of 0.3g-1g:1ml can ensure sufficient adhesive loading while achieving uniform distribution.

[0098] As a carrier of shear-hardening adhesive, the fineness of the roving directly affects the load-bearing space and impregnation uniformity of the adhesive. If the roving fineness is too low (<200 tex), the fiber bundle diameter is too small, the porosity of the fiber aggregate decreases, and the space available for shear-hardening adhesive adsorption is limited, making it difficult to load a sufficient amount of functional medium. Furthermore, excessively fine roving is easily elongated or even broken during impregnation, leading to discontinuous yarn formation. Conversely, if the roving fineness is too high (>800 tex), the fiber bundle diameter is too large, making it difficult for fibers in the center of the aggregate to fully contact the shear-hardening adhesive, resulting in uneven distribution of the adhesive across the roving cross-section. Therefore… Choosing a roving fineness of 200tex-800tex ensures both sufficient colloid loading and uniform impregnation while maintaining yarn continuity. Furthermore, the roving is chosen as the carrier because its multi-fiber bundle aggregate structure possesses excellent bulkiness and abundant porosity, providing a high-capacity adsorption space and numerous attachment points for the shear-hardening adhesive. Simultaneously, the roving, after carding and drawing, exhibits good fiber straightness, parallelism, and orientation, resulting in uniform yarn evenness and stable fineness. This allows the shear-hardening adhesive to penetrate and anchor uniformly within the fiber network during impregnation, thus guaranteeing the homogeneity of the functional medium distribution.

[0099] High-performance fiber filaments, used as core yarns, have their fineness determining the basic mechanical properties and final yarn diameter. If the fineness is too low (<100D), the cost of high-performance fiber filaments increases, and the processing difficulty increases, which is not conducive to industrial promotion. If the fineness is too high (>600D), the yarn diameter is too coarse, the softness decreases, and stress concentration is easily generated when subjected to impact loads. Therefore, selecting a fineness range of 100D-600D can ensure excellent mechanical properties while taking into account cost and processability.

[0100] Example 3:

[0101] The basic content is the same as in Example 1, except that in the first step, the volatile organic solvent is any one or a combination of anhydrous ethanol and acetone.

[0102] In application, the role of volatile organic solvents is to dissolve and disperse the shear hardener, forming a uniform and stable shear hardener dispersion. This allows the colloid to fully penetrate and adhere to the fiber network during roving impregnation. The selected solvent must have good solubility for the shear hardener, a fast evaporation rate, and be quickly removed after impregnation without affecting the colloidal properties. Anhydrous ethanol and acetone are both low-boiling-point organic solvents (boiling point below 120°C at standard atmospheric pressure), with fast evaporation rates at room temperature, allowing for rapid drying after impregnation and avoiding solvent residue. Both have good solubility for polyborosiloxane shear hardeners, forming a stable dispersion system. Among them, anhydrous ethanol has low toxicity and good safety, while acetone has stronger solubility. Both can meet the process requirements and can be selected according to actual production conditions.

[0103] Example 4:

[0104] The basic content is the same as in Example 1, except that in the first step, immersing the roving in the shear-hardening adhesive dispersion and ultrasonically treating it at room temperature until the roving is coated with white colloid to obtain modified roving means: first immersing the roving in the shear-hardening adhesive dispersion and ultrasonically treating it at room temperature, the ultrasonic power of the ultrasonic treatment is 50W-300W, and after ultrasonic treatment for 20min-40min, the modified roving is obtained.

[0105] In application, the roving is first immersed in the shear-hardening adhesive dispersion and then ultrasonically treated at room temperature. Room temperature immersion is chosen to avoid the solvent of the shear-hardening adhesive dispersion evaporating too quickly, which would cause changes in the concentration of the dispersion and affect the uniformity of immersion.

[0106] The ultrasonic power is selected between 50W and 300W because: if the power is too low (<50W), the cavitation effect is weak and the colloid penetration efficiency is low; if the power is too high (>300W), it may cause the shear-hardened gel dispersion to separate into layers, which will destroy the stability of the dispersion system.

[0107] The ultrasonic treatment time is 20-40 minutes because: if the ultrasonic time is too short (<20 minutes), the colloid will not penetrate sufficiently, resulting in a low content of shear-hardening adhesive adhering to the roving, which will affect the impact resistance; if the ultrasonic time is too long (>40 minutes), too much solvent in the shear-hardening adhesive dispersion will evaporate, increasing the concentration of the dispersion and causing uneven adhesion of the colloid to the roving.

[0108] Example 5:

[0109] The basic content is the same as in Example 1, except that: in the first step of this invention, the mixing and stirring of the shear hardening adhesive with the volatile organic solvent to obtain the shear hardening adhesive dispersion means: first, mixing the volatile organic solvent and the shear hardening adhesive to obtain mixture A; then stirring mixture A in a closed environment until there are no obvious flocculent or precipitate substances in mixture A, and then stopping the stirring to obtain the shear hardening adhesive dispersion.

[0110] In application, shear-hardening adhesive and volatile organic solvent are added to a container to obtain mixture A. Mixture A is then stirred using a magnetic stirrer. During stirring, the container opening is sealed with a sealing film to prevent solvent evaporation. The stirring speed is 200 rpm-500 rpm. After stirring for 1-3 hours, stirring is stopped to obtain a shear-hardening adhesive dispersion.

[0111] The stirring speed is 200rpm-500rpm because: if the stirring speed is too low (<200rpm), the efficiency will be low and the time required will be long; if the speed is too high (>500rpm), it will easily lead to solvent evaporation.

[0112] Stirring for 1-3 hours is because: if the stirring time is too short (<1 hour), the shear-hardened adhesive will not dissolve sufficiently; if the time is too long (>3 hours), the solvent will also evaporate.

[0113] Example 6:

[0114] The basic content is the same as in Embodiment 1, except that: in the second step, the rolling process is achieved by a rolling device 4, which includes an input guide rod 41, an output gear 5, a pressure roller 6, a telescopic spring component 7, an output guide rod 8, and a winding mechanism 9; the input guide rod 41, the output gear 5, and the output guide rod 8 are aligned; the pressure roller 6 is located directly above the output gear 5, and the pressure roller 6 and the output gear 5 are arranged vertically opposite each other; a rolling gap 51 is formed between the pressure roller 6 and the output gear 5 to allow the composite roving 1 to pass through; the top of the pressure roller 6 is connected to the bottom of the telescopic spring component 7; the input guide rod 41 is located on the inlet side of the rolling gap 51, and the input guide rod 41 introduces the composite roving 1 into the rolling gap 51; the output guide rod 8 is located on the outlet side of the rolling gap 51, and the output guide rod 8 guides the functional roving 11 after the rolling process to the winding mechanism 9.

[0115] When applying, such as Figure 1 As shown, the rolling process is performed on the rolling device 4. Specifically, the composite roving 1 is guided by the input guide rod 41 and enters the rolling gap 51 formed between the pressure roller 6 and the output gear 5. When the composite roving 1 passes through the rolling gap 51, under the action of the telescopic spring component 7, the pressure roller 6 applies rolling pressure to the composite roving 1, causing the composite roving 1 to thin in the vertical direction and widen in the horizontal direction, pressing it into a flat strip of functional roving 11. The functional roving 11 is then guided by the output guide rod 8 and collected and formed by the winding mechanism 9. The pressure roller 6 is located directly above the output gear 5, and the contact position between the two is the rolling point. The output gear 5 is driven to rotate by a motor, providing a support point for the rolling and outputting the rolled functional roving 11, without participating in the drafting.

[0116] Specifically, the telescopic spring component 7 includes an adjusting nut 71, a spring 72, a pressure block 73, a pressure arm 74, and a screw 75; one end of the screw 75 is fixedly connected to the frame of the roller pressing device 4, and the other end of the screw 75 is threadedly connected to the adjusting nut 71; the spring 72 is sleeved on the outside of the screw 75, the upper end of the spring 72 contacts the bottom of the adjusting nut 71, and the lower end of the spring 72 contacts the top of the pressure block 73; the bottom of the pressure block 73 contacts the top of the pressure arm 74; the rear end of the pressure arm 74 is connected to the roller pressing device 4. The frame of device 4 is hinged, and the front end of the pressure arm 74 presses against the top of the pressure roller 6. When it is necessary to control the roller pressure, the position of the adjusting nut 71 on the screw 75 is changed by rotating the adjusting nut 71, thereby changing the compression of the spring 72. The elastic force generated after the spring 72 is compressed is transmitted to the pressure arm 74 through the pressure block 73, pushing the front end of the pressure arm 74 to apply downward pressure to the pressure roller 6, thereby adjusting the roller pressure of the pressure roller 6 on the composite roving 1, ensuring that the composite roving 1 is pressed into a flat strip functional roving 11 with uniform thickness and consistent width.

[0117] Example 7:

[0118] The basic content is the same as in Example 1, except that: in the second step, the rolling pressure of the rolling process is 1MPa-5MPa, and the rolling output speed is 5r / min-20r / min; in the second step, the functional roving 11 is a flat strip; the thickness of the functional roving 11 is 0.3mm-1.2mm, and the width of the functional roving 11 is 5mm-10mm.

[0119] In application, the function of roll pressing is to press the composite roving 1 with shear hardening adhesive adsorbed into a flat strip functional roving 11 with reduced thickness and increased width from a cylindrical shape with a larger diameter; on the one hand, it enables the shear hardening adhesive to form a tight composite with the roving fiber, enhancing the bonding strength between the two; on the other hand, it creates conditions for subsequent wrapping processes through densification treatment.

[0120] The rolling pressure is 1MPa-5MPa because: if the pressure is too low (<1MPa), the rolling is insufficient, the composite roving 1 is difficult to be pressed into shape, and a regular flat strip cannot be obtained, and the shear hardening adhesive is not tightly bonded to the fiber; if the pressure is too high (>5MPa), the fibers of the composite roving 1 may be broken, destroying the integrity of the fiber structure and affecting the mechanical properties of the functional roving strip 11.

[0121] The roller pressing output speed is 5r / min-20r / min because: if the speed is too low (<5r / min), the production efficiency is low; if the speed is too high (>20r / min), the composite roving 1 will stay in the roller pressing gap 51 for too short a time, the roller pressing will be insufficient, and it will be difficult to achieve the ideal densification effect.

[0122] By controlling the above-mentioned rolling parameters, a flat, strip-shaped functional roving 11 is obtained, with a thickness of 0.3mm-1.2mm and a width of 5mm-10mm. The thickness of the functional roving 11 is mainly controlled by the solid-liquid ratio of the shear-hardening adhesive dispersion and the rolling pressure: the solid-liquid ratio determines the shear-hardening adhesive content attached to the roving; the higher the solid-liquid ratio, the greater the adhesive load, and the greater the thickness after rolling. The rolling pressure directly affects the degree of compression; the greater the pressure, the smaller the thickness. The width of the functional roving 11 is mainly controlled by the roving fineness and the rolling pressure: the finer the roving, the larger the original diameter of the fiber aggregate, and the wider it widens after rolling; the greater the rolling pressure, the more fully the fiber bundle widens laterally, and the wider it becomes.

[0123] The thickness of the functional roving 11 is controlled at 0.3mm-1.2mm because: if the thickness is too thin (<0.3mm), the mechanical strength is insufficient, and it is easy to break during wrapping, affecting the continuity of yarn formation; if the thickness is too thick (>1.2mm), the yarn diameter is too large, affecting weaving processing. The width of the functional roving 11 is controlled at 5mm-10mm because: if the width is too narrow (<5mm), a higher twist is required to achieve complete coverage, resulting in reduced yarn formation efficiency; if the width is too wide (>10mm), the roving is easy to twist during wrapping, causing uneven wrapping.

[0124] Compared to the original cylindrical composite roving 1, the flat structure of the functional roving 11 has the following advantages: the reduced thickness can reduce the final yarn diameter, avoiding the impact of excessively thick yarn on weaving; the increased width can increase the coverage area during wrapping, allowing for uniform and tight wrapping with a lower twist during subsequent wrapping, thereby improving spinning efficiency (under a constant spindle speed, the wrapping spinning speed is inversely proportional to the wrapping twist); at the same time, the flat strip is easier to flatten evenly and tightly wrap around the core yarn under the action of wrapping tension, eliminating the uneven distribution of the functional medium along the yarn length direction and ensuring the consistency of impact resistance throughout the process.

[0125] Example 8:

[0126] The basic content is the same as in Example 1, except that in the third step, the step of using high-performance fiber filament 3 as the core yarn and wrapping the two functional rovings 11 with opposite twist directions and the same twist in sequence on the surface of the high-performance fiber filament 3 means that the high-performance fiber filament 3 is used as the core yarn, and the two functional rovings 11 are wrapped with opposite twist directions and the same twist in sequence on the surface of the high-performance fiber filament 3 using a hollow spindle wrapping device 10; the spindle speed during wrapping is 2000rpm-6000rpm, and the twist is 200 twists / cm-1000 twists / cm.

[0127] When applying, such as Figure 3As shown, the hollow spindle covering device 10 includes a feeding mechanism 101, a spindle 115, a lower air ring ceramic component 107, an upper air ring ceramic component 108, an output mechanism 109, and a traverse winding mechanism 112; wherein, the feeding mechanism 101 includes a feeding roller 102, a tensioner 103, and a feeding guide rod 104; the spindle 115 includes a lower hollow spindle 105 and an upper hollow spindle 106; the output mechanism 109 includes an output roller 110 and an output guide rod 111;

[0128] The covering process of the hollow spindle covering device 10 is as follows: the high-performance fiber filament 3 is placed on the feeding mechanism 101 and fed in by the feeding roller 102. After that, it passes through the tensioner 103, the feeding guide rod 104, the lower hollow spindle 105, the lower air ring ceramic part 107, the upper hollow spindle 106, the upper air ring ceramic part 108, the output roller 110, and the output guide rod 111 in sequence, and is finally bound to the yarn bobbin of the transverse winding mechanism 112. At the same time, two functional rovings 11 are wound onto the lower hollow spindle yarn tube 114 corresponding to the lower hollow spindle 105 and the upper hollow spindle yarn tube 113 corresponding to the upper hollow spindle 106, respectively, and the yarn ends of the two functional rovings 11 are bound to the high-performance fiber filament 3 above.

[0129] During operation, the high-performance fiber filament 3 maintains a constant tension under the control of the tensioner 103, remaining taut throughout the entire winding range. The lower hollow spindle 105 and the upper hollow spindle 106 are driven by a drive device to rotate at high speeds, with the rotation speeds being identical. These drives the functional roving bobbins 11, which are sleeved on the upper hollow spindle yarn tube 113 and the lower hollow spindle yarn tube 114, to rotate synchronously. After the functional roving 11 is unwound from the upper hollow spindle yarn tube 113 and the lower hollow spindle yarn tube 114, the lower functional roving 11... The lower layer of the ceramic element 107 and the upper layer of the functional roving 11 form stable air rings through the upper layer ceramic element 108, which move in a circular motion around the axis of the spindle 115. When the high-performance fiber filament 3 emerges from the top of the spindle 115, it is tightly wrapped by the high-speed rotating functional roving 11 in a spiral trajectory. Each rotation of the spindle 115 forms a twist. The wrapped yarn is pressed by the output roller 110, guided by the output guide rod 111, and finally guided and wound into shape by the transverse winding mechanism 112.

[0130] The spindle speed refers to the rotation speed of the lower hollow spindle 105 and the upper hollow spindle 106. The reason for choosing 2000-6000 rpm is that if the speed is too low (<2000 rpm), the spinning efficiency will be low and the wrapping tension will be insufficient, making it difficult for the functional roving to be tightly wrapped around the core yarn; if the speed is too high (>6000 rpm), the wrapping tension will be too large, which may cause the functional roving to be stretched or even broken during the wrapping process, affecting the yarn quality.

[0131] The twist is 200-1000 twists / cm because: if the twist is too low (<200 twists / cm), the wrapping will be sparse, the functional roving will not be tightly bonded to the core yarn, and relative slippage will easily occur during impact resistance, resulting in a decrease in impact resistance performance; if the twist is too high (>1000 twists / cm), there will be over-twisting, the yarn will feel stiff, and it may cause uneven wrapping and deterioration of evenness, which will affect the stability of impact resistance performance.

[0132] The rotation speed and twist of the lower hollow spindle 105 and the upper hollow spindle 106 are set to be the same in order to ensure that the two layers are wrapped with the same tightness and to avoid yarn twisting and uneven wrapping due to inconsistent wrapping tension.

[0133] Example 9:

[0134] The basic content is the same as in Example 1, except that in the third step, the high-performance fiber filament 3 is any one or any combination of aramid 1414 fiber, PBO fiber, ultra-high molecular weight polyethylene fiber, and polyimide fiber.

[0135] In application, the high-performance fiber filaments 3 mentioned above are all high-strength, high-modulus fibers commonly used in the field of impact protection; as core yarn, they can maintain structural integrity during impact, prevent yarn breakage or excessive deformation, provide stable support for the energy dissipation process of the outer functional roving 11, and at the same time endow the yarn with excellent basic mechanical properties; according to tests, the average strength of the yarn of the present invention reaches 4500cN-6500cN, and the first impact energy dissipation rate reaches 68%-85%.

[0136] Example 10:

[0137] The basic content is the same as in Example 1, except that: the composite yarn is prepared by the method of preparing a core-wrapped anti-impact composite yarn according to any one of claims 1-8; the composite yarn includes a high-performance fiber filament 3 and a covering layer 2; the high-performance fiber filament 3 is the core yarn; the covering layer 2 includes two functional rovings 11, which are made by impregnating roving with shear hardening adhesive and then rolling; one of the functional rovings 11 is wrapped around the surface of the high-performance fiber filament 3, and the other functional roving 11 is wrapped around the outer surface of the first functional roving 11 with opposite twist; the twist of the two functional rovings 11 is the same.

[0138] In application, the composite yarn is made into a fabric. When subjected to a sudden high-speed impact, the two functional rovings 11 in the covering layer 2 respond sequentially: the shear hardening adhesive in the inner functional roving 11, which is directly wrapped around the core yarn surface, hardens and dissipates energy first. When the impact energy is transferred to the outer functional roving 11, it hardens and dissipates energy again. At the same time, the roving fibers in the two functional rovings 11 are stretched and rub against each other, forming a multi-level synergistic energy dissipation mechanism. The high-performance fiber filament 3 maintains structural integrity during the impact process, providing stable support for the entire energy dissipation process. This bidirectional symmetrical wrapping structure makes the yarn uniformly stressed, effectively preventing unilateral wear and ensuring the stability of impact resistance. This gives the composite yarn both excellent impact resistance and long-term stability.

[0139] Example 11:

[0140] The basic content is the same as in Example 1, except that the mass of the shear hardening adhesive loaded on the functional roving 11 accounts for more than 70% of the total mass of the functional roving 11.

[0141] In application, the impact resistance of the yarn is mainly determined by the content of shear hardening adhesive. The higher the load, the higher the energy dissipation rate of a single impact. Tests show that when the load of shear hardening adhesive on the functional roving 11 reaches more than 70%, the energy dissipation rate of the yarn in this invention can reach 68%-85% for the first impact. If the load is less than 70%, the content of shear hardening adhesive is insufficient, making it difficult to form a continuous and complete energy dissipation layer in the roving fiber network, resulting in a significant decrease in impact resistance. However, the load is not always better the higher it is. If the content of shear hardening adhesive is too high, exceeding the bearing limit of the roving fiber network, the adhesive is prone to excessive accumulation on the surface of the roving. Due to the lack of effective adhesion sites on the surface, a cold flow phenomenon occurs, resulting in uneven distribution, which in turn affects the stability of the impact resistance.

[0142] Example 12:

[0143] The basic content is the same as in Example 1, except that: First step: Shear hardening adhesive and anhydrous ethanol are mixed and stirred at a solid-liquid ratio of 0.5g:1ml to obtain a uniform shear hardening adhesive dispersion; then 430tex polyester roving is immersed in the shear hardening adhesive dispersion and ultrasonically treated at 100W for 30min at room temperature to obtain modified roving; then the modified roving is placed in a room temperature environment to stand and dry overnight to obtain composite roving 1;

[0144] Step 2: The composite roving 1 is subjected to roller pressing device 4. The roller pressing pressure is 2MPa and the output gear speed is 8r / min to obtain functional roving strip 11. The thickness of functional roving strip 11 is 0.8mm and the width is 7mm.

[0145] Step 3: Using 100D aramid 1414 fiber filament as the core yarn, the rotation speed of the lower hollow spindle 105 and the upper hollow spindle 106 is set to 4000 rpm. The upper hollow spindle 106 is S-twist and the lower hollow spindle 105 is Z-twist, with a twist of 600 twists / cm. The two functional rovings 11 are wrapped around the core yarn surface in opposite directions and with the same twist through the hollow spindle wrapping device 10, resulting in a roving-wrapped core-type impact-resistant composite yarn, which is yarn sample one.

[0146] In application, to verify the influence of the bidirectional symmetrical wrapping structure and equal twist design on yarn performance, a comparative sample was prepared according to the preparation method of yarn sample one, as follows:

[0147] The first comparative yarn sample is made in the following way: In the third step, only a single functional roving 11 is wound onto the upper hollow spindle yarn tube 113 corresponding to the upper hollow spindle 106. The upper hollow spindle 106 is set to Z-twist for unidirectional wrapping, so that the functional roving 11 is wrapped around the core yarn surface in the Z-twist direction. The lower hollow spindle 105 does not place the functional roving 11 and does not work. The remaining steps and parameters are the same as those of the first yarn sample.

[0148] The second comparative yarn sample is made in the following way: In the third step, only a single functional roving 11 is wound onto the lower hollow spindle yarn tube 114 corresponding to the lower hollow spindle 105. The lower hollow spindle 105 is set to S-twist for unidirectional wrapping, so that the functional roving 11 is wrapped around the core yarn surface in the S-twist direction. The upper hollow spindle 106 does not place the functional roving 11 and does not work. The remaining steps and parameters are the same as those of the first yarn sample.

[0149] The third comparative yarn sample is different in that: in the third step, the rotation speed of the upper and lower spindles is 4000 rpm, the upper hollow spindle 106 is set to S twist with a twist of 400 twists / cm, and the lower hollow spindle 105 is set to Z twist with a twist of 800 twists / cm. The remaining steps and parameters are the same as those of the first yarn sample.

[0150] The fourth comparative yarn sample is made with the following differences: In the third step, the rotation speed of the upper and lower spindles is 4000 rpm, the upper hollow spindle 106 is set to S twist with a twist of 800 twists / cm, and the lower hollow spindle 105 is set to Z twist with a twist of 400 twists / cm. The remaining steps and parameters are the same as those of the first yarn sample.

[0151] Tensile and abrasion resistance tests were conducted on yarn sample 1 and control yarn samples 1 through 4. Each yarn was tested 10 times and the average value was taken. The results are shown in Table 1.

[0152] Table 1

[0153]

[0154] As shown in Table 1, comparative yarn samples 1 and 2 have a unidirectional wrapping structure, and their strength and abrasion resistance are lower than those of yarn sample 1. This indicates that unidirectional wrapping is prone to untwisting, twisting, and stress concentration, affecting the mechanical properties of the yarn. Although comparative yarn samples 3 and 4 are bidirectional wrapping, the twist of the upper and lower layers is inconsistent, and their strength and abrasion resistance are also lower than those of yarn sample 1. This indicates that inconsistent twist leads to uneven wrapping tension and yarn twisting. Yarn sample 1 adopts a bidirectional symmetrical wrapping structure with opposite twist directions and the same twist, which can effectively eliminate internal stress in the yarn and construct a uniform force chain transmission network. This is a key technical feature for achieving high strength, high abrasion resistance, and high stable impact resistance.

[0155] Example 13:

[0156] The basic content is the same as in Example 1, except that: First step: Shear hardening adhesive and anhydrous ethanol are mixed and stirred at a solid-liquid ratio of 0.4g:1ml to obtain a uniform shear hardening adhesive dispersion; then 400tex polyester roving is immersed in the shear hardening adhesive dispersion and ultrasonically treated at 100W for 40min at room temperature to obtain modified roving; then the modified roving is placed in a room temperature environment to stand and dry overnight to obtain composite roving 1;

[0157] Step 2: The composite roving 1 is subjected to roller pressing device 4, the roller pressing pressure is 3MPa and the output gear speed is 10r / min, to obtain functional roving strip 11, the thickness of functional roving strip 11 is 0.5mm and the width is 5.5mm.

[0158] Step 3: Using 200D PBO fiber filaments as the core yarn, the rotation speed of the lower hollow spindle 105 and the upper hollow spindle 106 is set to 4500 rpm. The upper hollow spindle 106 is Z-twist and the lower hollow spindle 105 is S-twist, with a twist of 800 twists / cm. The two functional rovings 11 are wrapped around the core yarn surface in opposite directions and with the same twist through the hollow spindle wrapping device 10, resulting in a roving-wrapped core-type impact-resistant composite yarn, which is sample A.

[0159] In application, to verify the influence of shear-curing adhesive load and wrapping structure on the impact resistance of yarn, the following comparative samples were prepared according to the preparation method of sample A:

[0160] Sample B: The difference from Sample A is that in the first step, the roving was not impregnated with the shear hardening adhesive dispersion (i.e., it was not impregnated), and the original roving was used directly for subsequent steps. The other parameters are the same as those of Sample A.

[0161] Sample C: The difference from Sample A is that in the third step, only a single functional roving 11 is wound onto the lower hollow spindle yarn tube 114 corresponding to the lower hollow spindle 105. The lower hollow spindle 105 is set to S twist for unidirectional wrapping. The upper hollow spindle 106 does not place the functional roving 11 and does not work. The other parameters are the same as those of Sample A.

[0162] Sample D: The difference from Sample A is that in the first step, the solid-liquid ratio of shear-hardening adhesive to anhydrous ethanol is 0.7g:1ml, and the other parameters are the same as those of Sample A.

[0163] Samples A, B, C, and D were fabricated, each measuring 5cm × 5cm. Impact resistance was tested using a falling ball impact tester: the fabric sample was placed on a testing platform, and a 100g steel ball was released freely from a height of 40cm to impact the fabric surface. The peak force during the impact was recorded using a pressure sensor. Each sample was tested 10 times, and the average value was taken. The peak impact force of the blank group (without fabric) was also tested simultaneously. The impact force dissipation rate was calculated using the following formula:

[0164] Dissipation rate = (Blank peak force - Sample peak force) / Blank peak force × 100%;

[0165] Test results are as follows Figure 4 As shown, the peak impact force of the blank group was 1765N; the peak impact force of sample A was 1271N lower than that of the blank, with an impact force dissipation rate of 72%; the impact force dissipation rate of sample B (without shear hardening adhesive) was only 6%, 66% lower than that of sample A, indicating that shear hardening adhesive is a necessary medium for yarn to achieve impact resistance; the impact force dissipation rate of sample C (unidirectional wrapping) was 59.7%, 12.3% lower than that of sample A, proving that the bidirectional symmetrical wrapping structure can make fuller use of the energy dissipation effect of shear hardening adhesive; the impact force dissipation rate of sample D (high solids content) was 76%, which was better than that of sample A, indicating that by appropriately increasing the shear hardening adhesive loading on the basis of optimized structure, the impact resistance performance can be further improved.

[0166] Example 14:

[0167] The basic content is the same as in Example 1, except that: First step: Shear hardening adhesive and anhydrous ethanol are mixed and stirred at a solid-liquid ratio of 0.6g:1ml to obtain a uniform shear hardening adhesive dispersion; then 250tex polyester roving is immersed in the shear hardening adhesive dispersion and ultrasonically treated at 100W for 40min at room temperature to obtain modified roving; then the modified roving is placed in a room temperature environment to stand and dry overnight to obtain composite roving 1;

[0168] Step 2: The composite roving 1 is subjected to roller pressing device 4, the roller pressing pressure is 2.5MPa and the output gear speed is 15r / min, to obtain functional roving strip 11, the thickness of functional roving strip 11 is 0.4mm and the width is 3.3mm.

[0169] Step 3: Using 200D ultra-high molecular weight polyethylene fiber filament as the core yarn, the rotation speed of the lower hollow spindle 105 and the upper hollow spindle 106 is set to 3800 rpm. The upper hollow spindle 106 is Z-twist and the lower hollow spindle 105 is S-twist, with a twist of 1000 twists / cm. The two functional rovings 11 are wrapped around the core yarn surface in opposite directions and with the same twist through the hollow spindle wrapping device 10, resulting in a roving-wrapped core-type impact-resistant composite yarn, which is sample E.

[0170] In application, to verify the influence of composite rovings and high-performance fiber filaments on the impact resistance stability of yarn, the following comparative samples were prepared according to the preparation method of sample E:

[0171] Sample F differs from Sample E in that steps one and two are omitted, i.e., composite roving and functional roving strips are not prepared. In step three, the core yarn is 200D ultra-high molecular weight polyethylene fiber filament. Two 200D ultra-high molecular weight polyethylene fiber filaments are wound onto the corresponding hollow spindle yarn tubes of the lower hollow spindle 105 and the upper hollow spindle 106, respectively, as outer wrapping yarn for bidirectional wrapping (i.e., ordinary filaments are used instead of functional roving strips, without shear hardening adhesive). The remaining parameters are the same as those of Sample E.

[0172] Sample G: The difference from Sample E is that in the third step, the core yarn is replaced with ordinary cotton sewing thread, and the other parameters are the same as those of Sample E;

[0173] Samples E, F, and G were fabricated into fabrics with a sample size of 5cm × 5cm. Continuous impact tests were conducted using a falling ball impact tester: a 100g steel ball was released freely from a height of 40cm to impact the fabric surface, and the peak force of each impact was recorded. Each sample was continuously impacted 100 times, and the force dissipation rate of each impact was calculated and compared with the dissipation rate of the first impact.

[0174] Test results are as follows Figure 5 As shown, after 100 consecutive impacts, the impact force dissipation rate of sample E decreased by only 4.1% compared to the initial value; the impact force dissipation rate of sample F (non-functional roving) decreased by 46.4% compared to the initial value; and the impact force dissipation rate of sample G (ordinary cotton core yarn) decreased by 12.9% compared to the initial value. The results indicate that by loading shear hardening adhesive onto the roving and coating it onto the surface of high-performance fiber filaments, the impact resistance stability of the yarn can be significantly improved, and it can still maintain excellent energy dissipation capacity under repeated impacts.

[0175] Example 15:

[0176] The basic content is the same as in Example 1, except that: First step: Shear hardening adhesive and anhydrous ethanol are mixed and stirred at a solid-liquid ratio of 0.3g:1ml to obtain a uniform shear hardening adhesive dispersion; then 400tex cotton roving is immersed in the shear hardening adhesive dispersion and ultrasonically treated at 100W for 30min at room temperature to obtain modified roving; then the modified roving is placed in a room temperature environment to stand and dry overnight to obtain composite roving 1;

[0177] Step 2: The composite roving 1 is subjected to roller pressing device 4. The roller pressing pressure is 2MPa and the output gear speed is 8r / min to obtain functional roving strip 11. The thickness of functional roving strip 11 is 0.8mm and the width is 7mm.

[0178] Step 3: Using 100D aramid 1414 fiber filament as the core yarn, the rotation speed of the lower hollow spindle 105 and the upper hollow spindle 106 is set to 4000 rpm. The upper hollow spindle 106 is S-twist and the lower hollow spindle 105 is Z-twist, with a twist of 600 twists / cm. The two functional rovings 11 are wrapped around the core yarn surface in opposite directions and with the same twist through the hollow spindle wrapping device 10, resulting in a roving-wrapped core-type impact-resistant composite yarn, which is sample H.

[0179] In application, the preparation of sample I differs from that of sample H in that: in the first step, the solid-liquid ratio of shear-hardening adhesive to anhydrous ethanol is 0.9 g: 1 ml, and the roving is 400 tex wool roving; all other steps and parameters are the same as those for sample H.

[0180] To verify the structural advantages of roving as a carrier, the following comparative samples were prepared according to the preparation methods of samples H and I:

[0181] Sample J: The difference from Sample H is that the cotton roving in the first step is replaced with ordinary 20S cotton sewing thread, and the second step of rolling treatment is omitted (i.e., no rolling is performed, and the impregnated cotton sewing thread is directly used as the outer yarn for the third step). The other parameters are the same as those of Sample H.

[0182] Sample K: The difference from Sample I is that the wool roving in the first step is replaced with ordinary 20S wool sewing thread, and the second step of rolling treatment is omitted (i.e., no rolling is performed, and the impregnated cotton sewing thread is directly used as the outer yarn for the third step). The other parameters are the same as those of Sample I.

[0183] Samples H, I, J, and K were fabricated. Each fabric sample was left to stand at room temperature for 60 days, and the impact force dissipation rate was tested on day 0 and day 60. The impact test method was the same as in Example 13: a falling ball impact tester was used, and a 100g steel ball was released freely from a height of 40cm to impact a 5cm×5cm fabric sample. The peak force was recorded and the dissipation rate was calculated. Each sample was tested 10 times and the average value was taken.

[0184] Test results are as follows Figure 6 As shown, after 60 days of rest, the impact dissipation rates of samples H and I decreased by 2.5% and 9.1% respectively compared to the initial values; while the impact dissipation rates of samples J (cotton sewing thread) and K (wool sewing thread) decreased by 77.2% and 73.2% respectively compared to the initial values. The results indicate that the porous, high specific surface area fiber bundle structure of the roving provides a large number of adhesion sites for the shear-hardening adhesive, enabling long-term robust loading of the functional medium. Combined with the dense composite formed by the roll forming process, it effectively suppresses the cold flow and migration of the medium, ensuring excellent durability of the impact resistance performance from both material and process perspectives.

[0185] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A method for preparing a roving-wrapped core-type impact-resistant composite yarn, characterized in that: The method includes the following steps: Step 1: First, mix and stir the shear hardening adhesive with a volatile organic solvent to obtain a shear hardening adhesive dispersion; then, immerse the roving in the shear hardening adhesive dispersion and sonicate it at room temperature until the roving is coated with white colloid to obtain modified roving; then, dry the modified roving at room temperature to obtain composite roving (1). Step 2: Roller pressing is performed on the above composite roving (1) to obtain functional roving strip (11). Step 3: Using high-performance fiber filament (3) as the core yarn, wrap two of the above-mentioned functional rovings (11) with opposite twist directions and the same twist in sequence around the surface of the high-performance fiber filament (3) to obtain a roving core-wrapped anti-impact composite yarn.

2. The method for preparing a roving-wrapped core-type impact-resistant composite yarn according to claim 1, characterized in that: In the first step, the solid-liquid ratio of the shear-hardening adhesive to the volatile organic solvent in the shear-hardening adhesive dispersion is 0.3g-1g:1ml; In the first step, the fineness of the roving is 200tex-800tex; In the third step, the fineness of the high-performance fiber filament (3) is 100D-600D.

3. The method for preparing a roving-wrapped core-type impact-resistant composite yarn according to claim 1, characterized in that: In the first step, the volatile organic solvent is any one or a combination of anhydrous ethanol and acetone.

4. The method for preparing a roving-wrapped core-type impact-resistant composite yarn according to claim 1, characterized in that: In the first step, immersing the roving in the shear-hardening adhesive dispersion and ultrasonically treating it at room temperature until the roving is coated with a white colloid to obtain modified roving refers to: First, the roving is immersed in the shear-hardening adhesive dispersion and then subjected to ultrasonic treatment at room temperature. The ultrasonic power of the ultrasonic treatment is 50W-300W, and the ultrasonic treatment lasts for 20min-40min to obtain the modified roving.

5. The method for preparing a roving-wrapped core-type impact-resistant composite yarn according to claim 1, characterized in that: In the second step, the rolling process is achieved by a rolling device (4), which includes an input guide rod (41), an output gear (5), a pressure roller (6), a telescopic spring component (7), an output guide rod (8), and a winding mechanism (9). The input guide rod (41), the output gear (5), and the output guide rod (8) are aligned. The pressure roller (6) is located directly above the output gear (5), and the pressure roller (6) and the output gear (5) are arranged vertically opposite each other; a roller gap (51) is formed between the pressure roller (6) and the output gear (5) for the composite roving (1) to pass through. The top of the pressure roller (6) is connected to the bottom of the telescopic spring component (7); The input guide rod (41) is located at the entrance side of the roller pressing gap (51), and the input guide rod (41) introduces the composite roving (1) into the roller pressing gap (51); the output guide rod (8) is located at the exit side of the roller pressing gap (51), and the output guide rod (8) guides the functional roving strip (11) after roller pressing to the winding mechanism (9).

6. The method for preparing a roving-wrapped core-type impact-resistant composite yarn according to claim 1, characterized in that: In the second step, the rolling pressure of the rolling process is 1MPa-5MPa, and the rolling output speed is 5r / min-20r / min; In the second step, the functional roving strip (11) is a flat strip; the thickness of the functional roving strip (11) is 0.3mm-1.2mm, and the width of the functional roving strip (11) is 5mm-10mm.

7. The method for preparing a roving-wrapped core-type impact-resistant composite yarn according to claim 1, characterized in that: In the third step, the step of using high-performance fiber filament (3) as the core yarn and wrapping two of the above-mentioned functional rovings (11) with opposite twist directions and the same twist in sequence around the surface of the high-performance fiber filament (3) means: Using high-performance fiber filament (3) as the core yarn, a hollow spindle wrapping device (10) is used to wrap two of the above-mentioned functional rovings (11) in opposite directions and with the same twist in sequence around the surface of the high-performance fiber filament (3); the spindle speed during wrapping is 2000rpm-6000rpm and the twist is 200 twists / cm-1000 twists / cm.

8. The method for preparing a roving-wrapped core-type impact-resistant composite yarn according to claim 1, characterized in that: In the third step, the high-performance fiber filament (3) is any one or any combination of aramid 1414 fiber, PBO fiber, ultra-high molecular weight polyethylene fiber, and polyimide fiber.

9. A roving-wrapped core-type impact-resistant composite yarn, characterized in that: The composite yarn is prepared by the method of preparing a roving core-wrapped impact-resistant composite yarn according to any one of claims 1-8; The composite yarn includes high-performance fiber filaments (3) and a covering layer (2). The high-performance fiber filament (3) is the core yarn; The covering layer (2) includes two functional roving strips (11), which are made by impregnating roving with shear hardening adhesive and then rolling. One of the functional rovings (11) is wrapped around the surface of the high-performance fiber filament (3), and the other functional roving (11) is wrapped around the outer surface of the first functional roving (11) with opposite twist; the twist of the two functional rovings (11) is the same.

10. The roving-wrapped core-type impact-resistant composite yarn according to claim 9, characterized in that: The mass of the shear hardening adhesive loaded on the functional roving (11) accounts for more than 70% of the total mass of the functional roving (11).

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