Dot-bonded inorganic crimped core wrapped flame-retardant yarn and its spinning method and device

Abstract

The present invention provides a dot-bonded inorganic twisted core-coated flame-retardant yarn, its spinning method and device. The flame-retardant yarn comprises a core layer and a cortex layer; the core layer is a ply yarn formed by twisting and dot-bonding inorganic high-temperature resistant filaments and flame-retardant staple fiber slivers, and phytic acid-catalyzed adhesives are evenly distributed on the surface and inside of the core layer; the cortex layer is flame-retardant fibers spun from flame-retardant materials. The ply yarn of the core layer of the flame-retardant yarn of the present invention adopts a dot-bonded structure, and it is not easy for the ply yarns to slip off each other, and it has relatively high mechanical strength; the presence of the phytic acid-catalyzed adhesives can improve the adhesion between the core layer and the cortex layer; the inorganic high-temperature resistant filaments in the core layer can provide a fireproof framework for the flame-retardant yarn when continuously burning in an open fire, and the flame-retardant fibers in the core layer and the cortex layer in-situ catalyze to form a carbon oxide layer attached to the inorganic high-temperature resistant filaments in a high-temperature open fire environment, thereby performing organic-inorganic hybridization to achieve the flame-retardant effect.

Description

Technical Field

[0001] The present invention relates to the technical field of flame-retardant fabrics, and particularly to a dot-bonded inorganic twisted-core wrapped flame-retardant yarn, a spinning method thereof, and a device therefor. Background Art

[0002] In recent years, the number of fires caused by textiles and the resulting economic losses are higher than those caused by other reasons, and it has become a major social problem. To prevent fires from occurring, in addition to strengthening fire prevention measures, many countries also use textiles with flame-retardant effects. Flame-retardant textiles can extend the time for personnel to evacuate and take measures to extinguish fires, thereby reducing casualties and economic losses. Therefore, the development of flame-retardant textiles has become an irresistible trend. The development of flame-retardant textiles depends on the preparation of flame-retardant yarns.

[0003] Cotton fibers have good hygroscopicity, air permeability, and warmth retention, and seaweed fibers can further improve hygroscopicity. Therefore, cotton fibers and seaweed fibers are widely used in the preparation of textiles. The patent with the application number CN202111663787.6 discloses a flame-retardant yarn and a preparation process thereof. The flame-retardant yarn is made of composite fibers treated with a biological flame retardant. The composite fibers are fibers composed of cotton fibers and seaweed fibers. The biological flame retardant includes the following components in parts by weight: 20-30 parts of flame-retardant proteins, 10-15 parts of phosphonate compounds, 9-12 parts of phosphorous acid, 20-30 parts of formaldehyde solution, and 150-200 parts of phytic acid solvent. When the fabric prepared from the flame-retardant yarn obtained by this method continues to burn in the presence of an open flame, the seaweed fibers and cotton fibers will be damaged, resulting in the destruction of the overall structure of the fabric.

[0004] In view of this, it is necessary to design an improved dot-bonded inorganic twisted-core wrapped flame-retardant yarn, a spinning method thereof, and a device therefor to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a dot-bonded inorganic twisted-core wrapped flame-retardant yarn, a spinning method thereof, and a device therefor. The core layer of the flame-retardant yarn is composed of a ply yarn in which inorganic high-temperature resistant filaments and flame-retardant staple fiber rovings are twisted and dot-bonded to each other. At the same time, phytic acid catalytic adhesives are evenly distributed on the surface and inside of the core layer. The skin layer is flame-retardant fibers blended from flame-retardant materials. The inorganic high-temperature resistant filaments in the core layer can provide a fireproof skeleton for the flame-retardant yarn when continuously burning in an open flame. The flame-retardant fibers in the core layer and the skin layer are in-situ catalyzed to form a carbon dioxide layer on the inorganic high-temperature resistant filaments in a high-temperature open flame environment, thereby performing organic-inorganic hybridization to achieve the flame-retardant effect.

[0006] To achieve the above-mentioned invention object, the present invention provides a dot-bonded inorganic twisted core-coated flame-retardant yarn, which comprises a core layer and a cortex layer; the core layer is a ply yarn formed by twisting and dot-bonding inorganic high-temperature-resistant filaments and flame-retardant staple fiber sliver, and phytic acid-catalyzed adhesives are evenly distributed on the surface and inside of the core layer; the cortex layer is flame-retardant fiber spun from flame-retardant materials.

[0007] As a further improvement of the present invention, the inorganic high-temperature-resistant filament is one of basalt fiber filament, pre-oxidized fiber, carbon fiber filament, quartz fiber, and ceramic fiber; the flame-retardant staple fiber sliver is one of seaweed / cotton fiber blended staple fiber sliver and seaweed / flame-retardant viscose fiber blended staple fiber sliver.

[0008] As a further improvement of the present invention, the cortex layer is flame-retardant fiber spun from flame-retardant nylon, aramid 1313, and flame-retardant viscose staple fiber.

[0009] To achieve the above-mentioned invention object, the present invention also provides a spinning device for the dot-bonded inorganic twisted core-coated flame-retardant yarn, which is used to prepare the dot-bonded inorganic twisted core-coated flame-retardant yarn described above, and comprises a core layer preparation unit, a phytic acid padding unit, a cortex layer wrapping unit, and a second winding unit;

[0010] The core layer preparation unit comprises a drafting feeding unit, an intermittent bonding unit, and a first winding unit; the intermittent bonding unit comprises a sizing slurry tank, a profiled sizing roller arranged above the sizing slurry tank, and a hot air flow arranged between the sizing slurry tank and the first winding unit;

[0011] The dot-bonded core layer prepared by the core layer preparation unit is padded with phytic acid by the phytic acid padding unit, then wrapped with the cortex layer by the cortex layer wrapping unit to obtain a flame-retardant yarn, and then wound into a roll by the second winding unit.

[0012] As a further improvement of the present invention, the profiled sizing roller comprises a central circular roller and a plurality of parallel convex strips evenly distributed on the surface of the central circular roller.

[0013] As a further improvement of the present invention, the phytic acid padding unit adopts a two-padding and two-rolling process, and the impregnation time for each padding is 10 - 20 min, and the liquor pickup rate is 60% - 90%.

[0014] As a further improvement of the present invention, the phytic acid padding unit comprises a first feeding roller, a first padding trough, a first padding roller, a second padding trough, and a second padding roller arranged in sequence along the conveying direction of the core layer.

[0015] As a further improvement of the present invention, the cortical wrapping unit includes a second feeding roller for feeding cortical flame-retardant fibers, a carding roller, a friction roller disposed below the carding roller, and an output roller disposed at the input end of the second winding unit. A negative-pressure air suction mechanism is provided in the friction roller; the flame-retardant fibers fed by the second feeding roller are broken into single-fiber state by the carding roller, and then fed into the nip formed by the friction roller. Under the adsorption of the negative-pressure air suction mechanism inside the friction roller, they adhere to the surface of the friction roller. Under the high-speed rotation of the friction roller, the cortical layer in the single-fiber state is twisted on the outer layer of the core layer input to the cortical wrapping unit to form the flame-retardant yarn.

[0016] As a further improvement of the present invention, the drafting and feeding unit includes a trumpet for feeding the flame-retardant staple fiber sliver S12, a back roller and a back apron, a middle roller and a middle apron, a yarn guide wheel for guiding the inorganic high-temperature resistant filament, and a front roller and a front apron. The inorganic high-temperature resistant filament and the flame-retardant staple fiber sliver are respectively output from different positions of the nip formed by the front roller and the front apron.

[0017] The first winding unit includes a yarn guide hook, a traveler, a ring, and a bobbin. The flame-retardant yarn enters the balloon twisting section through the yarn guide hook and is finally wound onto the bobbin through the rotation of the traveler on the ring.

[0018] To achieve the above-mentioned invention purpose, the present invention also provides a spinning method for a dot-bonded inorganic twisted core-wrapped flame-retardant yarn. The core-spun yarn is spun by using the spinning device for the dot-bonded inorganic twisted core-wrapped flame-retardant yarn described in any one of the above, and specifically includes the following steps:

[0019] S1'. Feed the inorganic high-temperature resistant filament and the flame-retardant staple fiber sliver into the drafting and feeding unit respectively and form a ply yarn; then feed the ply yarn into the intermittent bonding unit for intermittent bonding and sizing to obtain the core layer, and then twist and wind it through the first winding unit.

[0020] S2'. Feed the core layer into the phytic acid padding unit for phytic acid double padding and double rolling treatment, and then feed it into the cortical wrapping unit.

[0021] S3'. The cortical layer fed by the cortical wrapping unit and the core layer padded with phytic acid are subjected to friction spinning so that the cortical layer wraps around the outer layer of the core layer to form the flame-retardant yarn.

[0022] S4'. The flame-retardant yarn is fed into the second winding unit and wound into a package.

[0023] The beneficial effects of the present invention are:

[0024] (1) The dot-bonded inorganic twisted core wrapped flame-retardant yarn provided by the present invention has a core layer composed of a composite yarn formed by twisting and dot-bonding inorganic high-temperature resistant filaments and flame-retardant staple fiber sliver. At the same time, phytic acid-catalyzed adhesives are uniformly distributed on the surface and inside of the core layer, and the skin layer is flame-retardant fibers spun from flame-retardant materials. First of all, the composite yarns in the core layer are not easy to slip off and have relatively high mechanical strength. Secondly, the presence of phytic acid-catalyzed adhesives can improve the adhesion between the core layer and the skin layer. At the same time, the synergistic flame retardancy of phytic acid, the core layer and the skin layer can further improve the flame retardancy of the flame-retardant yarn. In addition, the inorganic high-temperature resistant filaments can maintain their original structure after continuous combustion with high-temperature open flames, and can be used as a flame-retardant skeleton to further improve the flame retardancy of the flame-retardant yarn.

[0025] The inorganic high-temperature resistant filaments in the core layer can maintain their original inorganic network skeleton structure during continuous combustion with open flames, thereby providing a fireproof skeleton for the flame-retardant yarn. At the same time, they can effectively block the open flames. At the same time, the flame-retardant fibers in the core layer and the skin layer are in-situ catalyzed to form a carbon dioxide layer attached to the inorganic high-temperature resistant filaments in a high-temperature open flame environment, thereby carrying out organic-inorganic hybridization to achieve the flame-retardant effect. Furthermore, the flame-retardant fibers in the skin layer are melted in a high-temperature open flame environment, and the molten skin layer adheres to the core layer to form a protective shell, achieving the role of hierarchical synergistic flame retardancy.

[0026] (2) The spinning device of the dot-bonded inorganic twisted core wrapped flame-retardant yarn provided by the present invention first spins inorganic high-temperature resistant filaments and flame-retardant staple fiber sliver into a composite yarn through ring spinning, and then dot-bonds the composite yarn through a profiled sizing roller. The viscous sizing agent tightly bonds the two together, enhancing their interfacial bonding force and preventing slippage between the two. And the two support each other, to a certain extent solving the problems that inorganic non-elastic fibers such as inorganic high-temperature resistant filaments are easy to break and not soft, expanding the application range of inorganic fiber flame-retardant materials, and having a wide applicability to materials.

[0027] Then, the core layer is subjected to two-dip-two-roll treatment with phytic acid, so that phytic acid adheres to the surface and inside of the core layer. Phytic acid fully fills the voids inside the core layer, making the combination between inorganic high-temperature resistant filaments, flame-retardant staple fiber sliver, and different roots of high-temperature resistant filaments and different flame-retardant staple fibers more compact. It not only improves the bonding fastness between the components, but also the more compact solid core structure further avoids the entry of air, thereby further improving the flame retardancy on the one hand. At the same time, compared with the fully bonded composite yarn, the core layer structure of the present invention provides a more sufficient infiltration channel for phytic acid, so that a sufficient content of phytic acid is uniformly and fully attached to the surface and inside of the core layer. At the same time, the fully bonded composite yarn is hard and cannot solve the problem that inorganic non-elastic fibers such as inorganic high-temperature resistant filaments are easy to break. On the other hand, compared with the completely non-bonded composite yarn, the core layer structure of the present invention will not slip off each other while adhering to a sufficient content of phytic acid, so as not to damage the structure of the core layer.

[0028] Then, the core layer impregnated with phytic acid is fed into the cortical wrapping unit for cortical wrapping. Subsequently, the viscosity of the phytic acid adhering to the surface of the core layer adsorbs more cortical layers onto the core layer. Then, phytic acid serves as an adhesive to enhance the interfacial adhesion force between the core layer and the cortical layer, thereby enabling a relatively strong adhesive force between the cortical layer and the core layer. Since the core layer contains flame-retardant staple fibrils, i.e., staple fibers, partial hairiness is present on the surface of the core layer. These hairinesses will participate in the twisting and holding together between fibers during the wrapping of the staple fibers in the cortical layer, further improving the interfacial adhesion force between the core layer and the cortical layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the dot-bonded inorganic twisted core-wrapped flame-retardant yarn of the present invention.

[0030] Figure 2 It is a schematic structural diagram of the spinning device of the dot-bonded inorganic twisted core-wrapped flame-retardant yarn of the present invention.

[0031] Figure 3 It is a spinning path diagram of the core layer.

[0032] Figure 4 a is the apparent structural diagram of the flame-retardant yarn S3 in Example 1; 4b is the apparent structural diagram of the flame-retardant yarn S3 in Example 1 after burning when encountering high-temperature open fire; the scales are both 1 mm.

[0033] Figure 5 a is the apparent structural diagram of the flame-retardant yarn S3 in Example 1 under an electron microscope; 5b is the apparent structural diagram of the flame-retardant yarn S3 in Example 1 after burning when encountering high-temperature open fire under an electron microscope; the scales are both 300 μm.

[0034] REFERENCE SIGNS

[0035] S1 - core layer; S2 - cortical layer; S11 - inorganic high-temperature resistant filament; S12 - flame-retardant staple fibril;

[0036] 10 - drafting and feeding unit; 11 - trumpet; 12 - back roller; 13 - back top roller; 14 - middle roller; 15 - middle top roller; 16 - yarn guide wheel; 17 - front roller; 18 - front top roller;

[0037] 20 - intermittent bonding unit; 21 - profiled sizing roller; 22 - sizing slurry tank; 23 - hot air flow;

[0038] 30 - first winding unit; 31 - yarn guide hook; 32 - traveller; 33 - ring; 34 - bobbin;

[0039] 40 - phytic acid impregnating unit; 41 - first feeding roller; 42 - first impregnating tank; 43 - first impregnating roller; 44 - second impregnating tank; 45 - second impregnating roller;

[0040] 50 - Cortical wrapping unit; 51 - Second feeding roller; 52 - Combing roller; 53 - Friction roller; 54 - Output roller; 60 - Second winding unit. Detailed implementation mode

[0041] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0043] In addition, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0044] Please refer to Figure 1 As shown, the present invention provides a dot-bonded inorganic twisted core-wrapped flame-retardant yarn, including a core layer S1 and a cortical layer S2. The core layer S1 is a ply yarn formed by twisting and dot-bonding an inorganic high-temperature resistant filament S11 and a flame-retardant staple fiber sliver S12, and a phytic acid-catalyzed adhesive is uniformly distributed on the surface and inside of the core layer S1; the cortical layer S2 is a flame-retardant fiber made of a blend of flame-retardant materials. With such a setting, first, the inorganic high-temperature resistant filament S11 and the flame-retardant staple fiber sliver S12 are twisted into a ply yarn and dot-bonded, making it difficult for them to slip off each other, so that the resulting flame-retardant yarn has high mechanical strength; second, the presence of the phytic acid-catalyzed adhesive can not only improve the flame-retardant performance of the core layer S1, but also improve the adhesion between the core layer S1 and the cortical layer S2, improving the flame-retardant performance of the yarn while enhancing its mechanical strength; third, the inorganic high-temperature resistant filament S11 can maintain its original structure even after continuous combustion by high-temperature open fire, and can serve as a flame-retardant skeleton to further improve the flame-retardant performance of the flame-retardant yarn.

[0045] Specifically, the inorganic high-temperature resistant filament S11 is one of basalt fiber filament, pre-oxidized fiber, carbon fiber filament, quartz fiber, and ceramic fiber. The flame-retardant staple fiber sliver S12 is one of seaweed / cotton fiber blend staple fiber sliver and seaweed / flame-retardant viscose fiber blend staple fiber sliver. The cortical layer S2 is a flame-retardant fiber made of a blend of flame-retardant polyamide, aramid 1313, and flame-retardant viscose staple fiber.

[0046] Please refer to Figures 2 to 3As shown in the figure, the present invention also provides a spinning device for a dot-bonded inorganic twisted core-wrapped flame-retardant yarn, which includes a core layer preparation unit, a phytic acid padding unit 40, a cortex wrapping unit 50, and a second winding unit 60.

[0047] Among them, the core layer preparation unit includes a drafting and feeding unit 10, an intermittent bonding unit 20, and a first winding unit 30. The intermittent bonding unit 20 includes a slurry tank 22, a profiled sizing roller 21 arranged above the slurry tank 22, and a hot air flow 23 arranged between the slurry tank 22 and the first winding unit 30. With such a setting, after the dot-bonded core layer S1 prepared by the core layer preparation unit is padded with phytic acid by the phytic acid padding unit 40, it is wrapped with a flame-retardant fiber cortex S2 by the cortex wrapping unit 50 to obtain a flame-retardant yarn S3, and the obtained flame-retardant yarn S3 is then wound into a roll by the second winding unit 60.

[0048] Preferably, the profiled sizing roller 21 is a sizing roller with a profiled symmetric cross-section, including a central circular roller and a plurality of parallel rib structures uniformly distributed on the surface of the central circular roller. With such a setting, during the rotation of the profiled sizing roller 21, the rib structures on its surface will contact the viscous slurry in the slurry tank 22 and attach the viscous slurry in the slurry tank 22 to the rib structures. Then, the rib structures contact the ply yarn formed by the inorganic high-temperature resistant filament S11 and the flame-retardant staple fiber whisker S12, so as to adhere the viscous slurry to the ply yarn. During this process, no viscous slurry will adhere to the central circular roller, and at the same time, the central circular roller will not contact the ply yarn. Since the rib structures are uniformly distributed on the surface of the central circular roller, only when the rib structures contact the ply yarn, will the viscous slurry be uniformly adhered to the ply yarn. Specifically, when the rib structures contact the ply yarn, the viscous slurry adheres to the ply yarn, the surface of the rib separates from the ply yarn, and the adhesion of the viscous slurry ends. Wait for the next rib structure to contact the ply yarn to start the next adhesion cycle. Subsequently, the hot air flow 23 dries and cures the viscous slurry on the ply yarn. On the basis of the mutual twisting and plying of the inorganic high-temperature resistant filament S11 and the flame-retardant staple fiber whisker S12, the viscous slurry further tightly bonds the two in a dot pattern, enhancing their interfacial bonding force and preventing slippage between the two; at the same time, the inorganic high-temperature resistant filament S11 and the flame-retardant staple fiber whisker S12 support each other, and to a certain extent, solve the problems that the inorganic high-temperature resistant filament S11, especially inorganic inelastic fibers such as basalt fiber filaments, are prone to brittle fracture and not soft.

[0049] The drafting feeding unit 10 includes a bell mouth 11 for feeding the flame-retardant staple fiber strands S12, a rear roller 12 and a rear leather roller 13, a middle roller 14 and a middle leather roller 15, a yarn guide wheel 16 for guiding the inorganic high-temperature resistant filament S11, and a front roller 17 and a front leather roller 18. The inorganic high-temperature resistant filament S11 and the flame-retardant staple fiber strands S12 are respectively output from different positions of the jaws formed by the front roller 17 and the front leather roller 18. The twist formed by the rotation of the balloon (i.e., the twist generated by the core-spun yarn winding unit 30) is transmitted from bottom to top, so that the inorganic high-temperature resistant filament S11 and the flame-retardant staple fiber strands S12 output from the front roller 17 are twisted together to form a plied yarn.

[0050] The first winding unit 30 includes a yarn guide hook 31, a wire ring 32, a steel collar 33 and a spun yarn tube 34. The point-bonded core layer S1 enters the balloon twisting section through the yarn guide hook 31. The two strands of the core layer S1 are further twisted and tightened in this process, and finally are wound onto the spun yarn tube 34 through the rotation of the wire ring 32 on the steel collar 33.

[0051] Next, the core layer S1 wound on the first winding unit 30 is fed to the phytic acid padding unit 40 for phytic acid padding treatment.

[0052] The phytic acid padding unit 40 adopts a two-dipping and two-rolling process, the dipping time of each dipping and rolling is 10-20 minutes, and the liquid rolling rate is 60%-90%. In particular, the phytic acid padding unit 40 includes a first feeding roller 41, a first dipping tank 42, a first dipping roller 43, a second dipping tank 44 and a second dipping roller 45 arranged in sequence along the conveying direction of the core layer S1. The core layer S1 is fed between the two first feeding rollers 41, and enters the first dipping tank 42 after being output by the first feeding roller 41; after being infiltrated by the phytic acid in the first dipping tank 42, it enters between the two first dipping rollers 43 to roll off the excess phytic acid on the core layer S1; then enters the second dipping tank 44 for a second phytic acid dipping, and after further being fully infiltrated with phytic acid, enters between the two second dipping rollers 45 to further roll off the excess phytic acid on the core layer S1. Then it is input to the skin layer wrapping unit 50 for coating the skin layer S2.

[0053] During this process, phytic acid adheres to the surface and interior of the core layer S1. Since the core layer S1 is a point-bonded structure, on the one hand, compared with completely bonded plied yarns, the core layer structure of the present invention provides more sufficient infiltration channels for phytic acid, so that a sufficient amount of phytic acid is evenly and fully attached to the surface and interior of the core layer S1; on the other hand, compared with completely non-bonded plied yarns, the core layer structure of the present invention will not slip off each other while adhering to a sufficient amount of phytic acid, thereby not destroying the structure of the core layer.

[0054] Specifically, first of all, phytic acid, as a natural organic phosphorus compound, has a phosphorus content of up to 28% in its flame-retardant element, showing excellent flame-retardant effects. An adequate amount of phytic acid adheres evenly and fully to the surface and inside of the core layer S1. In the face of high-temperature environments such as open flames, phytic acid, the inorganic high-temperature resistant filament S11, and the flame-retardant staple fiber strand S12 can cooperate in flame retardance, thus improving the flame-retardant performance of the core layer S1. Secondly, phytic acid fully fills the voids inside the core layer S1, making the combination between the inorganic high-temperature resistant filament S11, the flame-retardant staple fiber strand S12, as well as different roots of high-temperature resistant filaments and different flame-retardant staple fibers more compact. This not only improves the bonding fastness between the components but also further prevents the entry of air due to the more compact solid-core structure, thereby further enhancing the flame-retardant performance. Thirdly, the phytic acid adhering to the surface of the core layer S1 is relatively moist and has a certain stickiness. When the subsequent cortical layer S2 is wrapped, it can adsorb more of the cortical layer onto the core layer S1. Then, phytic acid acts as an adhesive, enhancing the interfacial adhesion force between the core layer S1 and the cortical layer S2, thus making the bonding force between the cortical layer S2 and the core layer S1 strong. Additionally, the abundant hydroxyl groups in phytic acid can chemically bond with both the core layer S1 and the cortical layer S2, further improving the bonding force between the core layer S1 and the cortical layer S2.

[0055] The cortical wrapping unit 50 includes a second feeding roller 51 for feeding the cortical layer S2 (i.e., the cortical flame-retardant fiber), a carding roller 52, and a friction roller 53 disposed below the carding roller 52. A negative-pressure air suction mechanism is provided in the friction roller 53 (the negative-pressure air suction mechanism is provided in both friction rollers 53). The rotation directions of the second feeding roller 51, the carding roller 52, and the friction roller 53 are perpendicular to the rotation directions of the first feeding roller 41, the first padding roller 43, and the second padding roller 45, that is, the input directions of the core layer S1 and the cortical layer S2 are perpendicular to each other. Specifically, after the cortical flame-retardant fiber fed by the second feeding roller 51 is broken up into single-fiber state by the carding roller 52, it is then fed into the nip formed by the two friction rollers 53. At the same time, the core layer S1 also enters between the two friction rollers 53. The cortical layer S2 in single-fiber state is adsorbed by the negative-pressure air suction mechanism inside the friction roller 53 and adheres to the surface of the friction roller 53. Under the action of its high-speed rotation and the forward transportation of the core layer S1, the single-fiber state cortical layer S2 is twisted on the outer layer of the core layer S1 to form a flame-retardant yarn S3. That is, the core layer S1 is externally coated using friction spinning technology.

[0056] During this process, since the core layer S1 contains the flame-retardant staple fiber strand S12, that is, it contains staple fibers, there are some surface hairs on the surface of the core layer S1. These hairs will participate in the twisting and holding together between the fibers during the wrapping of the cortical layer S2 with staple fibers, further enhancing the interfacial adhesion force between the core layer S1 and the cortical layer S2.

[0057] The cortical wrapping unit 50 further includes an output roller 54 disposed at the input end of the second winding unit 60.

[0058] The flame retardant principle of the dot-bonded inorganic twisted core wrapped flame retardant yarn is as follows: The inorganic high-temperature resistant long filaments S11 in the core layer S1 can maintain the original inorganic network skeleton structure during continuous burning of an open flame, thereby providing a fireproof skeleton for the flame retardant yarn S3. At the same time, it can effectively block the open flame; the flame retardant fibers in the core layer S1 and the skin layer S2 are in-situ catalyzed to form a carbon dioxide layer in a high-temperature open flame environment and adhere to the inorganic high-temperature resistant long filaments S11, thereby carrying out organic-inorganic hybridization to achieve the flame retardant effect. At the same time, the flame retardant fibers in the skin layer S2 are melted in a high-temperature open flame environment, and the molten skin layer S2 adheres to the core layer S1 to form a protective shell, achieving the role of hierarchical synergistic flame retardancy.

[0059] The principle of the spinning device of the dot-bonded inorganic twisted core wrapped flame retardant yarn is as follows: After the flame retardant staple fiber sliver S12 is drawn by the trumpet-shaped orifice 11, the back roller 12 and the back roller 13, the middle roller 14 and the middle roller 15, and the front roller 17 and the front roller 18, it is output by the front roller 17; at the same time, the inorganic high-temperature resistant long filaments S11 are introduced onto the front roller 17 through the wire guide wheel 16 and are output by the front roller 17, and the inorganic high-temperature resistant long filaments S11 and the flame retardant staple fiber sliver S12 are output from different positions of the nip formed by the front roller 17 and the front roller 18 respectively; then the inorganic high-temperature resistant long filaments S11 and the flame retardant staple fiber sliver S12 output by the front roller 17 are twisted together to form a ply yarn by means of the twist formed by the rotation of the balloon; the ply yarn enters the intermittent bonding unit 20, and the profiled sizing roller 21 evenly bonds the viscous sizing material carried on the convex strip structure to the ply yarn during rotation, so that the ply yarn is intermittently bonded and sized, and is dried by the hot air flow 23 to obtain the dot-bonded core layer S1. Finally, it is wound onto the yarn bobbin 34 through the yarn guide hook 31, the traveler 32, and the ring 33 in the first winding unit 30. Then, the core layer S1 wound on the first winding unit 30 is fed into the phytic acid padding unit 40 for a two-padding and two-rolling process. After padding and removing the excess phytic acid, it is input into the skin layer wrapping unit 50; at the same time, the skin layer flame retardant fibers fed by the second feeding roller 51 are dispersed into single fiber state by the carding roller 52, and then fed into the nip formed by the two friction rollers 53. The skin layer S2 in the single fiber state is adsorbed by the negative pressure air suction mechanism inside the friction roller 53 and adheres to the surface of the friction roller 53. Under the action of its high-speed rotation and the forward conveying action of the core layer S1, the single fiber state skin layer S2 is twisted on the outer layer of the core layer S1 to form the flame retardant yarn S3, and then is fed into the second winding unit 60 by the output roller 54 and wound into a package.

[0060] The present invention also provides a spinning method for the dot-bonded inorganic twisted core wrapped flame retardant yarn, which uses the above-mentioned spinning device of the dot-bonded inorganic twisted core wrapped flame retardant yarn for core-spinning, and specifically includes the following steps:

[0061] S1'. Feed the inorganic high-temperature resistant filament S11 and the flame-retardant staple fiber sliver S12 into the drafting feeding unit 10 respectively to form a ply yarn; then feed the ply yarn into the intermittent bonding unit 20 for intermittent bonding and sizing to obtain the core layer S1, and then twist and wind through the first winding unit 30;

[0062] S2'. Feed the core layer S1 into the phytic acid padding unit 40 for two-padding and two-rolling treatment with phytic acid, and then feed it into the cortical wrapping unit 50;

[0063] S3'. The cortical layer S2 fed into the cortical wrapping unit 50 and the phytic acid-impregnated core layer S1 are friction-spun so that the cortical layer S2 covers the outer layer of the core layer S1 to form a flame-retardant yarn S3;

[0064] S4'. The flame-retardant yarn S3 is fed into the second winding unit 60 and wound into a package.

[0065] The present invention will be described in detail below through multiple embodiments.

[0066] Embodiment 1

[0067] A spinning method for a dot-bonded inorganic twisted core-wrapped flame-retardant yarn, wherein the inorganic high-temperature resistant filament S11 is a basalt filament fiber, the flame-retardant staple fiber sliver S12 is a fiber obtained by blending cotton fiber and seaweed fiber in a mass ratio of 5:1, and the cortical layer S2 is a flame-retardant fiber obtained by blending flame-retardant polyamide, aramid 1313, and flame-retardant viscose staple fiber in a mass ratio of 55:35:10.

[0068] The core layer S1 is subjected to two-padding and two-rolling treatment with a phytic acid solution. The impregnation time for each padding is 15 min, and the liquor pickup rate is 70%. The concentration of the phytic acid solution is 1.1 mol / L.

[0069] The flame-retardant yarn S3 wound into a package by the second winding unit 60 is dried in a drying cylinder at 80°C for 2 h to obtain a dried flame-retardant yarn S3.

[0070] As Figure 4 shown, Figure 4a is the apparent structure diagram of the flame-retardant yarn S3 in Embodiment 1, and Figure 4b is the apparent structure diagram of the flame-retardant yarn S3 in Embodiment 1 after burning in the presence of high-temperature open fire. As can be seen from Figure 4 Figure 4b, after burning in the presence of high-temperature open fire, the main structure of the flame-retardant yarn S3 does not break or lose its main body. The flame-retardant skeleton formed by the basalt filament fiber remains intact. The flame-retardant fibers in the cortical layer, the cotton fiber and seaweed fiber in the core layer undergo a rapid oxidation reaction in the high-temperature open fire environment, but there is no large-area shedding. Instead, a carbon layer is formed on its surface, and with the help of the flame retardancy of phytic acid, further combustion is prevented.

[0071] As Figure 5As shown, 5a is the apparent structure diagram of the flame-retardant yarn S3 of Example 1 under an electron microscope, and 5b is the apparent structure diagram of the flame-retardant yarn S3 of Example 1 after being burned by high-temperature open fire under an electron microscope. From Figure 5 it can be seen that the flame-retardant fibers in the cortex are melted in a high-temperature open-fire environment, and the molten cortex adheres to the core layer to form a protective shell, achieving the effect of hierarchical cooperative flame retardancy.

[0072] Examples 2-3

[0073] Compared with Example 1, the difference lies in that the impregnation time and the rolling liquor ratio of the dip-rolling treatment with phytic acid solution are different, and the other parameters are substantially the same as those of Example 1, which will not be elaborated here.

[0074] The flame-retardant yarns obtained in Examples 1-3 were made into flame-retardant fabrics, and the flame-retardant properties of the flame-retardant fabrics were tested. The specific test method was carried out in accordance with the relevant national thermal protection standards, and the results are shown in Table 1:

[0075] Table 1 Flame-retardant properties of the flame-retardant fabrics of Examples 1-3

[0076]

[0077] As can be seen from Table 1, within a certain range, as the impregnation time is prolonged and the impregnation and rolling rate is increased, the thermal protection performance TPP value of the flame-retardant fabric shows an increasing trend.

[0078] However, after the impregnation time is further prolonged or the impregnation and rolling rate is further increased, the thermal protection performance TPP value of the flame-retardant fabric tends to be stable.

[0079] Comparative Example 1

[0080] Compared with Example 1, the difference lies in that the profiled sizing roller 21 is replaced with an ordinary round roller, that is, the inorganic high-temperature-resistant filament S11 and the flame-retardant staple fiber strip S12 are linearly bonded instead of dot-bonded, and the other parameters are substantially the same as those of Example 1, which will not be elaborated here. The results show that the flame-retardant fabric prepared in Comparative Example 1 has a hard hand feeling and a significant decrease in softness. At the same time, the thermal protection value TPP of the fabric is lower than that of Example 1.

[0081] Comparative Example 2

[0082] Compared with Example 1, the difference lies in that the intermittent bonding unit 20 is not provided, that is, the inorganic high-temperature-resistant filament S11 and the flame-retardant staple fiber strip S12 are not bonded, and the other parameters are substantially the same as those of Example 1, which will not be elaborated here. The results show that the flame-retardant performance of the flame-retardant fabric prepared in Comparative Example 2 is basically the same as that of Example 1, but the organic fiber coating layer on the surface of the yarn slips severely with the core inorganic fiber filament, and the weaving efficiency decreases significantly.

[0083] Comparative Example 3

[0084] Compared with Example 1, the difference lies in that the core layer S1 is not subjected to phytic acid padding treatment, but directly coated with the skin layer S2, and the remaining parameters are substantially the same as those in Example 1, which will not be elaborated here. The results show that compared with Example 1, the flame-retardant yarns and fabrics prepared in Comparative Example 3 have a low charring amount, a slow charring rate, and a poor flame-retardant effect, and the TPP value is only 28.721 cal / cm 2 .

[0085] Comparative Example 4

[0086] Compared with Example 1, the difference lies in that the phytic acid padding treatment is replaced with piperazine pyrophosphate, and the remaining parameters are substantially the same as those in Example 1, which will not be elaborated here. The results show that compared with Example 1, the yarns and fabrics prepared in Comparative Example 4 have a low charring amount, a slow charring rate, and a poor flame-retardant effect, and the TPP value is 29.101 cal / cm 2 , and the synergistic catalytic effect cannot be exerted.

[0087] In summary, the dot-bonded inorganic twisted core-wrapped flame-retardant yarn provided by the present invention, and its spinning method and device, the core layer is composed of a ply yarn in which inorganic high-temperature resistant filaments and flame-retardant staple fiber whiskers are twisted with each other and dot-bonded, and at the same time, phytic acid catalytic adhesives are uniformly distributed on the surface and inside of the core layer, and the skin layer is flame-retardant fibers blended with flame-retardant materials; the ply yarns in the core layer are not easy to slip off and have high mechanical strength; the presence of the phytic acid catalytic adhesive can improve the adhesion between the core layer and the skin layer; the inorganic high-temperature resistant filaments in the core layer can provide a fireproof skeleton for the flame-retardant yarn when continuously burning in an open flame, and the flame-retardant fibers in the core layer and the skin layer are in-situ catalyzed to form a carbon oxide layer on the inorganic high-temperature resistant filaments in a high-temperature open flame environment, so as to carry out organic-inorganic hybridization to achieve the flame-retardant effect.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A dot-bonded inorganic crimped core-coated flame-retardant yarn, characterized in that, It includes a core layer and a skin layer; the core layer is a ply yarn formed by twisting and dot-bonding an inorganic high-temperature resistant filament and a flame-retardant staple fiber sliver, and a phytic acid-catalyzed adhesive is evenly distributed on the surface and inside of the core layer; the skin layer is a flame-retardant fiber spun from a flame-retardant material.

2. The dot-bonded inorganic crimped core-coated flame-retardant yarn according to claim 1, wherein, The inorganic high-temperature resistant filament is one of basalt fiber filament, pre-oxidized fiber, carbon fiber filament, quartz fiber, and ceramic fiber; the flame-retardant staple fiber sliver is one of seaweed / cotton fiber blended staple fiber sliver and seaweed / flame-retardant viscose fiber blended staple fiber sliver.

3. The dot-bonded inorganic twisted core-coated flame-retardant yarn according to claim 1, characterized in that, The skin layer is a flame-retardant fiber spun from flame-retardant polyamide, aramid 1313, and flame-retardant viscose staple fiber.

4. A spinning device for a dot-bonded inorganic twisted core-coated flame-retardant yarn, which is used to prepare the dot-bonded inorganic twisted core-coated flame-retardant yarn according to any one of claims 1 to 3, and is characterized in that, It includes a core layer preparation unit, a phytic acid padding unit, a skin layer wrapping unit, and a second winding unit; The core layer preparation unit includes a drafting feeding unit, an intermittent bonding unit, and a first winding unit; the intermittent bonding unit includes a slurry tank, a profiled sizing roller arranged above the slurry tank, and a hot air flow arranged between the slurry tank and the first winding unit; The dot-bonded core layer prepared by the core layer preparation unit is padded with phytic acid by the phytic acid padding unit, then wrapped with the skin layer by the skin layer wrapping unit to obtain a flame-retardant yarn, and then wound into a roll by the second winding unit.

5. The spinning device for the dot-bonded inorganic twisted core-coated flame-retardant yarn according to claim 4, characterized in that, The profiled sizing roller includes a central circular roller and a plurality of parallel convex strips evenly distributed on the surface of the central circular roller.

6. The spinning device for the dot-bonded inorganic twisted core-coated flame-retardant yarn according to claim 4, characterized in that, The phytic acid padding unit adopts a two-padding and two-rolling process, and the impregnation time for each padding is 10 - 20 min, and the liquor pickup rate is 60% - 90%.

7. The spinning device for the dot-bonded inorganic twisted core-coated flame-retardant yarn according to claim 6, characterized in that, The phytic acid padding unit includes a first feeding roller, a first padding tank, a first padding roller, a second padding tank, and a second padding roller arranged in sequence along the conveying direction of the core layer.

8. The spinning device for the dot-bonded inorganic crimped core-coated flame-retardant yarn according to claim 4, characterized in that, The skin layer wrapping unit includes a second feeding roller for feeding the skin layer flame-retardant fiber, a carding roller, a friction roller arranged below the carding roller, and an output roller arranged at the input end of the second winding unit. A negative pressure air suction mechanism is provided in the friction roller; the flame-retardant fiber fed by the second feeding roller is dispersed into a single fiber state by the carding roller, then fed into the nip formed by the friction roller, and adsorbed by the negative pressure air suction mechanism inside the friction roller, adheres to the surface of the friction roller, and under the high-speed rotation of the friction roller, the single fiber state skin layer is twisted on the outer layer of the core layer input to the skin layer wrapping unit to form the flame-retardant yarn.

9. The spinning device for the dot-bonded inorganic twisted core-coated flame-retardant yarn according to claim 4, characterized in that, The drafting feeding unit includes a trumpet for feeding the flame-retardant staple fiber sliver, a back roller and a back leather roller, a middle roller and a middle leather roller, a yarn guide wheel for guiding the inorganic high-temperature resistant filament, and a front roller and a front leather roller. The inorganic high-temperature resistant filament and the flame-retardant staple fiber sliver are respectively output from different positions of the nip formed by the front roller and the front leather roller; The first winding unit includes a yarn guide hook, a traveler, a ring, and a bobbin. The flame-retardant yarn enters the balloon twisting section through the yarn guide hook and is finally wound onto the bobbin through the rotation of the traveler on the ring.

10. A spinning method for a dot-bonded inorganic crimped core-coated flame-retardant yarn, characterized in that, Using the core-spun spinning device for the dot-bonded inorganic twisted core-coated flame-retardant yarn according to any one of claims 4 to 9 for core-spun spinning, specifically including the following steps: S1'. Feed the inorganic high-temperature resistant filaments and the flame-retardant staple fiber sliver into the drawing and feeding unit respectively to form a ply yarn; then feed the ply yarn into the intermittent bonding unit for intermittent bonding sizing to obtain the core layer, and then twist and wind through the first winding unit; S2'. Feed the core layer into the phytic acid padding unit for two-padding and two-rolling treatment with phytic acid, and then feed it into the skin layer wrapping unit; S3'. The skin layer fed into the skin layer wrapping unit and the core layer impregnated with phytic acid are subjected to friction spinning so that the skin layer covers the outer layer of the core layer to form the flame-retardant yarn; S4'. The flame-retardant yarn is fed into the second winding unit and wound into a package.

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