Biodegradable fiber fireproof flame-retardant yarn with core-sheath hollow structure and preparation method of biodegradable fiber fireproof flame-retardant yarn

Abstract

The invention provides a biodegradable core-sheath hollow-structure fiber fireproof flame-retardant yarn and a preparation method thereof.The preparation method comprises the following steps that rigid fiber filaments and soluble vinylon filaments are combined and twisted, and lossless core yarn of a spiral structure is prepared; soluble vinylon short fibers uniformly wrap the untwisted core yarn, meanwhile, the outer layers of the soluble vinylon short fibers are wrapped with polylactic acid fiber filaments, and the untwisted shrinkage yarn with the balanced torque is prepared; the method comprises the following steps: by taking an untwisted shrunk yarn as a core yarn, clockwise and anticlockwise wrapping a polylactic acid yarn by using a multifunctional wrapping machine to prepare a composite yarn with a compact and stable structure; the composite yarn passes through a warm water bath, soluble vinylon short fibers and soluble vinylon filaments in the middle layer of the composite yarn are removed through the characteristics of soluble vinylon, and yarn of a core-sheath hollow structure is prepared; the biodegradable basalt fiber fireproof heat-insulation yarn composite yarn which is stable in structure, fireproof, flame-retardant, good in heat-insulation performance, high in strength, smooth and clean is successfully prepared by spinning the rigid fiber filaments.

Description

Technical Field

[0001] The invention relates to the technical field of multi-component fiber composite spinning, in particular to a biodegradable core-sheath hollow structure fiber fire-retardant yarn and a preparation method thereof. Background Art

[0002] Fireproof and heat-insulating yarn plays an important role in preventing fire and heat protection, and has great application significance in the fields of high-rise fire prevention and fire rescue. At present, fireproof and heat-insulating fabrics are mainly made of high-performance organic and inorganic fiber spinning and weaving or dyeing and finishing of fabrics, such as polyimide fiber, flame-retardant viscose fiber, ceramic fiber-based fire-retardant fabrics, or inorganic flame-retardant nanoparticles, microcapsule phase change material finishing fabrics, etc. However, these products have the disadvantages of complex process, high cost, weak effect, and non-degradability, which greatly limits the development and application of fire-retardant yarns. Basalt fiber is directly drawn from basalt ore with abundant reserves in nature. It has the characteristics of low cost, natural degradability, and excellent fire-retardant effect. It is a potential material for the development of a new generation of high-performance fire-retardant yarns.

[0003] In the spinning and preparation process of basalt fiber, due to its inherent hardness and brittleness, it is easy to produce twisting and breaking during the spinning process. The tangled fibers will produce burrs and are difficult to wear. In order to solve the problem that the above-mentioned rigid fibers are prone to fiber bending and breaking during the spinning process, the basalt filaments are usually core-wrapped. In the prior art, patent number CN201110076746.7, entitled "A basalt core-spun yarn", proposes a method for preparing a core-spun yarn with basalt filaments as the core and flame-retardant short fibers as the shell. The specific method is to uniformly coat the basalt monofilament with flame-retardant viscose fiber, pre-oxidized fiber, flame-retardant nitrile fiber or / and Kevlar fiber blended fiber. The basalt core-spun yarn can be a flame-retardant woven fabric. However, the torque imbalance problem caused by the high stiffness of the basalt fiber is not solved. At the same time, the basalt core-spun yarn has poor elasticity, which is not conducive to wearing comfort.

[0004] In addition, the invention patent with patent number CN202010764123.8 discloses a high-rigidity brittle fiber material lossless coated yarn and its spinning method and fabric, which forms a straight lossless core-shell structure composite yarn with a yarn core (basalt fiber) by forward and reverse twisting of ring spinning and friction spinning. The invention patent with patent number CN202310567380.6 also discloses a method for preparing a rigid fiber twist-free composite yarn, which spins a torque-balanced composite yarn through the reverse torque of fibers of different components. Although these two methods can avoid the exposure of basalt fibers to form burrs and improve the wearability of the yarn, they cannot provide effective heat insulation, thereby further improving the fire retardant properties.

[0005] In view of this, it is necessary to design a preparation method of a biodegradable core-sheath hollow structure basalt fiber fireproof and heat-insulating yarn to solve the above problems. Summary of the invention

[0006] The main purpose of the present invention is to overcome the above disadvantages and shortcomings of the prior art and provide a method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure.

[0007] A method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure comprises the following steps:

[0008] Step 1, combining and twisting rigid fiber filaments with rigid fiber filaments to obtain a lossless core yarn with a spiral structure;

[0009] Step 2, uniformly covering the lossless core yarn with soluble vinylon staple fibers, and wrapping the outer layer of the soluble vinylon staple fibers with polylactic acid fiber filaments to obtain a torque-balanced twist-free yarn;

[0010] Step 3: using the torque-balanced untwisted yarn as the core yarn, and using a multifunctional wrapping machine to wrap the polylactic acid yarn in a clockwise and counterclockwise bidirectional manner to obtain a composite yarn with a compact and stable structure;

[0011] Step 4: Pass the composite yarn through a warm water bath, and utilize the characteristics of soluble vinylon to remove the soluble vinylon staple fibers in the middle layer of the composite yarn to obtain a yarn with a core-sheath hollow structure.

[0012] In one embodiment, in step 2, the lossless core yarn in step 1 is reversely untwisted by a transverse unwinding device to obtain untwisted rigid fiber filaments, and then the soluble vinylon staple fibers are uniformly coated on the rigid fiber filaments.

[0013] The present invention first performs a combined twisting treatment on the rigid fiber filaments, and then uses a lateral unwinding device to perform an untwisting treatment on them, so as to avoid the twisting shrinkage of the rigid fiber filaments that have been twisted during unwinding due to their own residual torque, and then uses a concentrated spinning method to perform a secondary twist on the rigid fiber filaments, and ensures that the twisting multiple of the secondary twisting is equal to the twisting multiple of the combined twisting, thereby effectively avoiding bending and breaking of the rigid fiber filaments during the spinning process, thereby damaging the structure of the rigid fiber filaments, causing the phenomenon of exposed hairiness, and affecting the yarn performance.

[0014] In one embodiment, in step 2, the twist direction of the soluble vinylon staple fiber and the polylactic acid fiber filament is opposite to the twist direction of the lossless core yarn.

[0015] In one embodiment, in step 2, the twist of the soluble vinylon staple fiber and the polylactic acid fiber filament is equal to the twist of the lossless core yarn.

[0016] In one embodiment, the polylactic acid fiber filament is a bio-based polylactic acid fiber filament, and the polylactic acid yarn is a bio-based polylactic acid staple fiber. Preferably, the bio-based polylactic acid staple fiber is a polylactic acid staple fiber S-twisted yarn and a polylactic acid staple fiber Z-twisted yarn prepared by ring spinning technology.

[0017] In one embodiment, in step 4, the impregnated core-sheath hollow structure yarn is passed through a drying device, stretched and shaped under the action of heat and moisture to form a stable core-sheath hollow composite yarn.

[0018] In one embodiment, the effective length of the drying area of ​​the drying device is 1m-2m, and the water temperature is controlled at 60-100°C.

[0019] In one embodiment, in step 4, the warm water bath has an effective length of 1m-3m and the water temperature is controlled at 80-100°C.

[0020] In one embodiment, in step 1, the pre-twist degree of the fiber filament is 100T / m-600T / m.

[0021] In one embodiment, in step 2, the polylactic acid fiber filaments pass through a self-leveling tension disk, and the tension range is controlled within 0.5N-5N.

[0022] In one embodiment of the present invention, the rigid fiber filaments are preferably basalt rigid fiber filaments.

[0023] A method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure comprises the following steps:

[0024] Step 1, combining and twisting the rigid fiber filaments and the soluble vinylon filaments to obtain a lossless core yarn with a spiral structure;

[0025] Step 2, uniformly covering the lossless core yarn with soluble vinylon staple fibers, and wrapping the outer layer of the soluble vinylon staple fibers with polylactic acid fiber filaments to obtain a torque-balanced twist-free yarn;

[0026] Step 3: using the torque-balanced untwisted yarn as the core yarn, and using a multifunctional wrapping machine to wrap the polylactic acid yarn in a clockwise and counterclockwise bidirectional manner to obtain a composite yarn with a compact and stable structure;

[0027] Step 4: Pass the composite yarn through a warm water bath, and utilize the characteristics of soluble vinylon to remove the soluble vinylon staple fibers and soluble vinylon filaments in the middle layer of the composite yarn to obtain a yarn with a core-sheath hollow structure.

[0028] In one embodiment, in the step 2, the lossless core yarn in step 1 is subjected to reverse untwisting, stretching and conveying treatment through a lateral unwinding device to obtain untwisted rigid fiber filaments, and then the soluble vinylon staple fibers are uniformly coated on the rigid fiber filaments.

[0029] The present invention combines and twists rigid fiber filaments with soluble vinylon flexible filaments to improve the flexibility of the core yarn, and then uses a lateral unwinding device to stretch and transport it to avoid the twisting of the twisted core yarn due to its own residual torque during unwinding. Then, the core yarn is twisted in the same multiple in the opposite direction using ring spinning technology, and the surface of the core yarn is coated with soluble vinylon staple fibers, while the outermost layer is wrapped with polylactic acid filaments to form a structurally stable core-spun yarn, which effectively avoids the bending and breaking of basalt filaments during the spinning process, and produces burrs. Through the above method, rigid fiber filaments made of basalt are successfully spun to produce biodegradable basalt fiber fireproof and heat-insulating yarn composite yarns with stable structure, fire retardancy, good heat insulation performance, high strength and smoothness. It can be understood that this method can be extended to the organic composite process of other rigid fibers and flexible fibers to develop multifunctional composite yarns.

[0030] A biodegradable fiber fireproof and flame-retardant yarn with a core-sheath hollow structure comprises a core yarn, an air layer and an outer sheath which are arranged in sequence from the inside to the outside. The core yarn is formed by twisting rigid fiber filaments and polylactic acid fiber filaments, and the outer sheath is formed by symmetrically wrapping the polylactic acid yarn in clockwise and counterclockwise directions.

[0031] The core yarn of the present invention is twisted from rigid fiber filaments and polylactic acid fiber filaments, and has high strength and flexibility. After dissolving the soluble vinylon staple fibers and the soluble vinylon filaments, an air layer is formed between the outer sheath and the core yarn, and the outer sheath and the core yarn form a stable structure under the friction and entanglement between the fibers. The core-sheath structure constructed by the bio-based polylactic acid staple fiber composite ensures the fireproof, flame retardant and high-strength properties of the basalt rigid fiber, while giving the composite yarn the effect of efficient heat insulation and flame retardancy, and insulates the basalt filaments from external friction during use, thereby improving the wearing performance and service life.

[0032] The present invention overcomes the key problem in the prior art that basalt fiber cannot be directly taken due to its high rigidity and brittleness. A core-sheath basalt fiber fireproof and heat-insulating yarn hollow structure is obtained through a specific preparation method. The composite structure yarn has excellent fireproof, flame-retardant and heat-insulating properties, and the polylactic acid fiber on the surface ensures the skin-friendliness of the yarn, so that the yarn can be used in the production of protective rescue products such as household fireproof curtains, life ropes, firefighting suits, high-temperature protective workwear, and firefighting tents.

[0033] The outer sheath of the present invention adopts polylactic acid short fiber yarn, and the cross-wrapping design not only ensures the stability of the yarn structure, but also improves the toughness and feel of the smooth outer sheath layer, extending the service life. At the same time, polylactic acid fiber is difficult to burn and smokeless, which enhances the overall fireproof performance of the yarn. In addition, polylactic acid fiber is biodegradable, and the production raw materials are sufficient and cheap. It is combined with basalt fiber to form a green low-carbon yarn. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of Example 1 of a method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure according to the present invention;

[0035] Figure 2 This is a schematic diagram of the structure used in step 1 of the method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure used in step 1 of the method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure used in step 4 of the method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn of the present invention;

[0038] Figure 5 It is a schematic block diagram of Example 2 of the method for preparing the biodegradable fiber fire-retardant yarn with a core-sheath hollow structure of the present invention;

[0039] Figure 6 It is a schematic structural diagram of the biodegradable core-sheath hollow structure fiber fire-retardant yarn of the present invention. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0045] The present invention provides a method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure, comprising the following steps:

[0046] Step 1, combining and twisting the rigid fiber filaments and the soluble vinylon filaments to obtain a lossless core yarn with a spiral structure;

[0047] Step 2, uniformly covering the lossless core yarn with soluble vinylon staple fibers, and wrapping the outer layer of the soluble vinylon staple fibers with polylactic acid fiber filaments to obtain a torque-balanced twist-free yarn;

[0048] Step 3: using the torque-balanced untwisted yarn as the core yarn, and using a multifunctional wrapping machine to wrap the polylactic acid yarn in a clockwise and counterclockwise bidirectional manner to obtain a composite yarn with a compact and stable structure;

[0049] Step 4: Pass the composite yarn through a warm water bath, and utilize the characteristics of soluble vinylon to remove the soluble vinylon staple fibers and soluble vinylon filaments in the middle layer of the composite yarn to obtain a yarn with a core-sheath hollow structure.

[0050] The present invention combines and twists rigid fiber filaments with soluble vinylon flexible filaments to improve the flexibility of the core yarn, and then uses a lateral unwinding device to stretch and transport it to avoid the twisting of the twisted core yarn due to its own residual torque during unwinding; then the core yarn is reversely twisted with the same multiple using ring spinning technology, and the surface of the core yarn is coated with soluble vinylon staple fibers, and the outermost layer is wrapped with polylactic acid filaments to form a structurally stable core-spun yarn, which effectively avoids the bending and breaking of basalt filaments during the spinning process and the generation of burrs; through the above method, the rigid fiber filaments made of basalt material are successfully spun to obtain a biodegradable basalt fiber fireproof and heat-insulating yarn composite yarn with stable structure, good fire retardancy, good heat insulation performance, high strength and smoothness.

[0051] Embodiment 1

[0052] See also Figures 1 to 4 The present invention provides a method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure, comprising the following steps:

[0053] Step S101, first unwind two rigid fiber filaments from the first filament reel 1 and the second filament reel 5 respectively, pass through the double-groove guide wheel 2 and the single-groove guide wheel 3 in turn, and move to the side of the first winding spindle 4 under the restriction of the first guide hook 6, and the rigid fiber filaments are combined and twisted by the rotation of the first winding spindle 4 to obtain rigid fiber filaments with a twist of 30 twists / cm. The rigid fiber filaments after the above-mentioned twisting treatment are wound onto the first winding spindle 4 for standby use; the rigid fiber filaments are preferably fiber filaments made of basalt material, but can also be other rigid fibers.

[0054] Step S102, the rigid fiber filament with a twist of 30 twists / cm on the first winding spindle 4 in step S101 is sleeved on the unwinding shaft 14 of the transverse unwinding device 7, and fixed by the fixing piston 18, so as to ensure that the reel of the rigid fiber filament is fixed on the unwinding shaft 14, and the transverse unwinding device 7 is used to perform reverse untwisting treatment on the rigid fiber filament with a certain twist to obtain the untwisted rigid fiber filament; the rigid fiber filament unwound from the reel is introduced through the guide wheel 8;

[0055] At the same time, the soluble vinylon staple fibers are unwound from the staple fiber roving tube 11, and are gripped and stretched by the rear roller 12, the middle roller 13, and the front roller 9 in turn, and are fed in parallel with the rigid fiber filaments. The soluble vinylon staple fibers are evenly coated on the surface of the rigid fiber filaments, and move toward the second winding spindle 10 under the restriction of the second wire guide hook 17. The rotation of the second winding spindle 10 drives the rigid fiber filaments to undergo secondary twisting to produce rigid fiber untwisted yarn, which is wound onto the second winding spindle 10.

[0056] Step S103, using the above-mentioned torque-balanced untwisted yarn as the core yarn, and using a multifunctional wrapping machine to realize clockwise and counterclockwise bidirectional wrapping of the polylactic acid yarn to obtain a composite yarn with a compact and stable structure; wherein the polylactic acid yarn is a polylactic acid staple fiber S-twisted yarn and a polylactic acid staple fiber Z-twisted yarn prepared by ring spinning technology.

[0057] Step S104, please refer to Figure 4 The composite yarn is passed through a warm water bath, and the middle layer of the composite yarn is removed by using the characteristics of soluble vinylon, that is, the soluble vinylon short fibers are removed to obtain a yarn with a core-sheath hollow structure. The soluble vinylon short fibers are made of bio-based polylactic acid short fiber bundles.

[0058] The size of the first winding spindle 4 and the second winding spindle 10 is 25 mm; the diameter of the guide wheel 8 is 8 cm, and the length of the internal rolling shaft is 7 cm; the unwinding speed of the transverse unwinding device 7 is 9.9 cm / min; the twist of the soluble vinylon staple fiber is 90 twists / cm, and the yarn count is 30. The twist multiple of the secondary twisting in step S102 is equal to the twist multiple of the twisting process in step S101, both of which are 30 twists / cm.

[0059] Among them, the guide wheel 8 can perform guide processing on the rigid fiber filaments to avoid bending of the rigid fiber filaments with a certain twist after being unwound from the transverse unwinding device 7, so as to ensure that the shape of the rigid fiber filaments changes during the spinning process as much as possible. The guide wheel 8 can rotate around the rolling axis inside it.

[0060] More specifically, in step S102, the unwinding speed of the lateral unwinding device 7 is 30 m / min, and the unwinding speed is equal to the linear speed of the front roller 9, ensuring that the rigid fiber filaments always remain in a straight state and avoiding the shrinkage of the rigid fiber filaments, so that the twist and structure of the rigid fiber filaments are not changed or destroyed after unwinding, thereby ensuring the stability of the rigid fiber filament structure.

[0061] More specifically, see Figure 3 In step S102, the transverse unwinding device 7 includes a support arm perpendicular to the ground and an unwinding shaft 14 arranged on the upper part of the support arm, one end of the unwinding shaft 14 is fixed to the support arm, and the other end is provided with a fixed piston 18 for fixing the first winding spindle 4 to the unwinding shaft 14, and an unwinding speed adjustment switch 15 and a device switch 16 are provided on the wall of the support arm. More specifically, a magnetic base is provided at the bottom of the support arm, and the cross-section of the magnetic base is "T-shaped", so that the support arm can be endowed with magnetism and the stability of the transverse unwinding device 7 can be ensured.

[0062] Embodiment 2

[0063] See also Figure 5 The present invention provides a method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure, comprising the following steps:

[0064] Step S101, first unwind a rigid fiber filament and a soluble vinylon filament from the first filament reel 1 and the second filament reel 5 respectively, pass through the double-groove guide wheel 2 and the single-groove guide wheel 3 in turn, and move to the side of the first winding spindle 4 under the restriction of the first guide hook 6. The rigid fiber filament and the soluble vinylon filament are combined and twisted by the rotation of the first winding spindle 4 to obtain a lossless core yarn with a spiral structure with a twist of 30 twists / cm. The rigid fiber filament that has undergone the above-mentioned twisting treatment is wound onto the first winding spindle 4 for standby use.

[0065] Step S102, put the lossless core yarn with a twist of 30 twists / cm on the first winding spindle 4 in step S101 on the unwinding shaft 14 of the transverse unwinding device 7, and fix it by the fixed piston 18 to ensure that the reel of the lossless core yarn is fixed on the unwinding shaft 14, and use the transverse unwinding device 7 to reverse untwist the lossless core yarn with a certain twist to obtain the untwisted rigid fiber filaments; the rigid fiber filaments unwound from the reel are introduced through the guide wheel 8; wherein, the soluble vinylon filaments are combined and twisted with the rigid fiber filaments to improve the flexibility of the core yarn, and then the transverse unwinding device 7 is used to stretch and transport it to avoid the twisting of the twisted core yarn due to its own residual torque during unwinding.

[0066] At the same time, the soluble vinylon staple fibers are unwound from the staple fiber roving tube 11, and are gripped and stretched by the rear roller 12, the middle roller 13, and the front roller 9 in turn, and are fed in parallel with the rigid fiber filaments. The soluble vinylon staple fibers are evenly coated on the surface of the rigid fiber filaments, and move toward the second winding spindle 10 under the restriction of the second wire guide hook 17. The rotation of the second winding spindle 10 drives the rigid fiber filaments to undergo secondary twisting to produce rigid fiber untwisted yarn, which is wound onto the second winding spindle 10.

[0067] Step S103: using the torque-balanced untwisted yarn as the core yarn, and using a multifunctional wrapping machine to wrap the polylactic acid yarn in both clockwise and counterclockwise directions to obtain a composite yarn with a compact and stable structure.

[0068] Step S104, passing the composite yarn through a warm water bath, and utilizing the characteristics of soluble vinylon to remove the middle layer of the composite yarn, that is, removing the soluble vinylon staple fibers and the soluble vinylon flexible filaments to obtain a yarn with a core-sheath hollow structure.

[0069] Embodiment 3

[0070] See also Figure 6 The present invention provides a biodegradable core-sheath hollow structure fiber fire-retardant yarn, comprising a core yarn 100, an air layer 200 and an outer sheath 300 arranged in sequence from the inside to the outside, the core yarn 100 is formed by twisting rigid fiber filaments and polylactic acid fiber filaments, and the outer sheath 300 is formed by symmetrically wrapping the polylactic acid yarn in clockwise and counterclockwise directions.

[0071] The core yarn 100 of the present invention is twisted by rigid fiber filaments and polylactic acid fiber filaments, and has high strength and flexibility. After dissolving the soluble vinylon staple fibers and the soluble vinylon filaments, an air layer 200 is formed between the outer sheath 300 and the core yarn 100, and the outer sheath 300 and the core yarn 100 form a stable structure under the friction and entanglement between the fibers. The core-sheath structure constructed by the bio-based polylactic acid staple fiber composite ensures the fireproof, flame retardant and high-strength performance of the basalt rigid fiber, while giving the composite yarn the effect of efficient heat insulation and flame retardancy, and insulates the basalt filaments from external friction during use, thereby improving the wearing performance and service life.

[0072] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0073] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure, characterized in that: The steps include: Step 1, combining and twisting rigid fiber filaments with rigid fiber filaments to obtain a lossless core yarn with a spiral structure; Step 2, uniformly covering the lossless core yarn with soluble vinylon staple fibers, and wrapping the outer layer of the soluble vinylon staple fibers with polylactic acid fiber filaments to obtain a torque-balanced twist-free yarn; Step 3: using the torque-balanced untwisted yarn as the core yarn, and using a multifunctional wrapping machine to wrap the polylactic acid yarn in a clockwise and counterclockwise bidirectional manner to obtain a composite yarn with a compact and stable structure; Step 4: Pass the composite yarn through a warm water bath, and utilize the characteristics of soluble vinylon to remove the soluble vinylon staple fibers in the middle layer of the composite yarn to obtain a yarn with a core-sheath hollow structure.

2. The method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn according to claim 1, characterized in that: In the step 2, the lossless core yarn in step 1 is subjected to reverse untwisting treatment through a transverse unwinding device to obtain untwisted rigid fiber filaments, and then the soluble vinylon staple fibers are uniformly coated on the rigid fiber filaments.

3. The method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn according to claim 1, characterized in that: In the step 2, the twist direction of the soluble vinylon staple fibers and the polylactic acid fiber filaments is opposite to the twist direction of the lossless core yarn.

4. The method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn according to claim 1, characterized in that: In the step 2, the twist of the soluble vinylon staple fiber and the polylactic acid fiber filament is equal to the twist of the lossless core yarn.

5. The method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn according to claim 1, characterized in that: In the step 4, the impregnated core-sheath hollow structure yarn passes through a drying device, and is stretched and shaped under the action of heat and moisture to form a stable core-sheath hollow composite yarn.

6. The method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn according to claim 5, characterized in that: The effective length of the drying area of ​​the drying device is 1m-2m, and the water temperature is controlled at 60-100°C.

7. The method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn according to claim 1, characterized in that: In step 4, the effective length of the warm water bath is 1m-3m, and the water temperature is controlled at 80-100°C.

8. A method for preparing a biodegradable fiber fire-retardant yarn with a core-sheath hollow structure, characterized in that: The steps include: Step 1, combining and twisting the rigid fiber filaments and the soluble vinylon filaments to obtain a lossless core yarn with a spiral structure; Step 2, uniformly covering the lossless core yarn with soluble vinylon staple fibers, and wrapping the outer layer of the soluble vinylon staple fibers with polylactic acid fiber filaments to obtain a torque-balanced twist-free yarn; Step 3: using the torque-balanced untwisted yarn as the core yarn, and using a multifunctional wrapping machine to wrap the polylactic acid yarn in a clockwise and counterclockwise bidirectional manner to obtain a composite yarn with a compact and stable structure; Step 4: Pass the composite yarn through a warm water bath, and utilize the characteristics of soluble vinylon to remove the soluble vinylon staple fibers and soluble vinylon filaments in the middle layer of the composite yarn to obtain a yarn with a core-sheath hollow structure.

9. The method for preparing the biodegradable core-sheath hollow structure fiber fire-retardant yarn according to claim 8, characterized in that: In the step 2, the lossless core yarn in step 1 is subjected to reverse untwisting, stretching and conveying treatment through a transverse unwinding device to obtain untwisted rigid fiber filaments, and then the soluble vinylon staple fibers are uniformly coated on the rigid fiber filaments.

10. A biodegradable fiber fire-retardant yarn with a core-sheath hollow structure, characterized in that: It comprises a core yarn, an air layer and an outer sheath which are arranged in sequence from the inside to the outside. The core yarn is formed by twisting rigid fiber filaments and polylactic acid fiber filaments, and the outer sheath is formed by symmetrically wrapping the polylactic acid yarn in clockwise and counterclockwise directions.

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