Flame-retardant anti-shrinkage high-performance covering yarn as well as preparation method and application thereof

Abstract

The limit oxygen index of the covering yarn is larger than or equal to 38%, the covering yarn is free of molten drops during vertical combustion, the thermal shrinkage rate at the high temperature of 300 DEG C is smaller than or equal to 5%, the flame-retardant retention rate after 20 times of washing is larger than or equal to 90%, and the covering yarn is suitable for the fields of fire protection, high-temperature industry and the like and has high flame retardance, dimensional stability and durability.

Description

Technical Field

[0001] The invention belongs to the field of textiles, and in particular relates to a flame-retardant, shrinkage-resistant, high-performance core-spun yarn and a preparation method and application thereof. Background Art

[0002] With the increasing requirements for material performance in the fields of industrial protection, fire-fighting equipment and special textiles, the development of flame-retardant fiber materials has become a research hotspot.

[0003] Flame-retardant fibers are the core of flame-retardant fiber materials, and can be divided into intrinsic flame-retardant fibers and modified flame-retardant fibers. Currently, there are three common flame-retardant fabric preparation processes: one is to directly use intrinsic high-performance flame-retardant fibers for fabric weaving, but due to their special monomer structure and preparation process, the cost is generally high; the second is to post-process modified flame-retardant fiber fabrics, such as attaching flame retardants or flame-retardant polymer layers to the fabric surface through dipping, spraying, coating, etc., but this will seriously affect the flame retardant durability and breathability of the fabric. The third is to blend intrinsic flame-retardant fibers with modified flame-retardant fibers, and balance flame retardancy, spinnability and cost through component regulation and process control. This is a way to develop flame-retardant fabrics that can balance performance and cost.

[0004] The flame retardancy and anti-drip issues have been addressed through blending processes, such as combining inherently flame-retardant fibers (polyimide, aramid) with modified flame-retardant fibers such as flame-retardant viscose, flame-retardant polyester, and flame-retardant acrylic. However, existing blending processes still face two major bottlenecks: first, the prominent problem of high-temperature thermal shrinkage. Most synthetic fibers (such as flame-retardant polyester and acrylic) have a thermal shrinkage rate exceeding 15% at 300°C, causing deformation or even failure of the fabric structure; second, insufficient interfacial bonding between the blended components leads to yarn delamination or mechanical property degradation, making it difficult to maximize the flame retardant and anti-shrinkage synergistic effects of the blended system.

[0005] Therefore, how to retain the flame retardant advantages of the blending process while overcoming the problems of thermal shrinkage and interface stability through material innovation and structural design has become the core challenge in the development of high-performance flame retardant fibers.

[0006] The blended system of polyimide fiber and flame-retardant acrylic fiber achieves a balance between high-performance flame retardancy and anti-melting droplet through the flame retardant synergistic effect: polyimide fiber can effectively inhibit the generation of molten droplets by virtue of its intrinsic flame retardancy (limiting oxygen index LOI 33% to 38%) and high-temperature non-melting characteristics (decomposition temperature > 500°C); while flame-retardant acrylic fiber (LOI 28% to 30%) further delays the combustion process through the gas phase flame retardant mechanism and the condensed phase carbonization effect. After the two are blended in a specific proportion, the LOI value is increased to ≥38%, and the rigid skeleton of polyimide and the flexible spinnability of flame-retardant acrylic fiber complement each other. While ensuring the mechanical properties of the yarn, it overcomes the defects of insufficient flame retardant efficiency or high processing difficulty of a single component. However, the combination of pure organic fibers cannot completely avoid the problem of thermal shrinkage at high temperatures.

[0007] Basalt fiber is an inorganic high-performance fiber made from natural basalt ore through high-temperature melting and drawing. In recent years, it has become a research hotspot in the field of flame retardant materials due to its unique physical and chemical properties.

[0008] However, the high modulus and low surface energy characteristics of basalt fiber lead to two major challenges in the traditional spinning process: first, the rigid fiber is easily broken due to bending stress during the drawing process; second, the interfacial bonding force between the smooth surface and the polymer cortex is weak, which seriously restricts its application in high-performance yarns.

[0009] In previous reports: Tian et al. prepared SBFs yarns with micro-nanostructure characteristics by electrospinning and studied the interfacial properties of SBFs-reinforced epoxy resin composites. (Composites Communications, Volume 23, February 2021, 100589). Liu Li et al. used a silane coupling agent (KH550) to treat the surface of BF. The wettability of the treated BF was enhanced, but at high temperatures, the amino groups in the coupling agent were easily oxidized and decomposed, resulting in a decrease in interfacial bonding strength, which limited its application in high-temperature resistant materials. (Journal of Building Materials, 2017, 20(4): 623-629.) Deng Muling et al. used NaOH solution to alkali-etch the surface of BF at different temperatures and found that with the increase of NaOH solution concentration and temperature, the fiber quality showed a downward trend (Silicate Bulletin, 2021, 40(06): 2062-2069.). Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a flame-retardant and shrinkage-resistant high-performance core-spun yarn and a preparation method and application thereof, which overcomes the problem of easy shrinkage of flame-retardant yarn in the prior art.

[0011] The invention provides a core-spun yarn, which comprises a core layer and a skin layer; the core layer is modified basalt fiber; and the skin layer is a blended yarn of polyimide fiber and flame-retardant acrylic fiber.

[0012] Furthermore, the core-spun yarn includes a core layer and a skin layer wrapped around the outside; the core layer is modified basalt fiber filament; and the skin layer is prepared from a roving blended with polyimide fiber and flame-retardant acrylic fiber.

[0013] Furthermore, it includes two parts: a core layer and a skin layer wrapped around the outside; wherein, the core layer is modified basalt fiber filament; and the skin layer is prepared by siro-spun coarse yarn blended with polyimide fiber and flame-retardant acrylic fiber.

[0014] Furthermore, the outer covering fiber is prepared by cleaning, carding, drawing, and roving the polyimide fiber and the flame-retardant acrylic fiber to obtain the outer layer roving, and then covering the outer layer of the basalt fiber filament with the two-ply blended roving through a siro spinning process to obtain the core-spun yarn.

[0015] The mass ratio of the core layer to the skin layer is (30-70):(70-30); the blending mass ratio of the polyimide fiber to the flame-retardant acrylic fiber in the skin layer is (30-60):(70-40).

[0016] The modified basalt fiber of the core layer is a continuous filament with a linear density of 0.5 to 2.5 dtex, a single filament tensile strength of ≥ 2000 MPa, an elongation at break of ≤ 3%, and is non-flammable;

[0017] The polyimide fiber of the cortex has a linear density of 0.6-1.67 dtex, a breaking strength of 3.0-5.2 cN / dtex, an elongation at break of 16-17%, and a limiting oxygen index of 33-38%; the flame-retardant acrylic fiber has a linear density of 1.5-6.0 dtex, a breaking strength of 2.5-4.0 cN / dtex, an elongation at break of 25-35%, and a limiting oxygen index of 28-30%.

[0018] The oxygen content of the surface of the modified basalt fiber is increased by ≥12%, and the roughness Ra is ≥1.2 μm.

[0019] The outer layer fibers are coated on the outside of the core yarn through a siro spinning process to obtain the core-spun yarn.

[0020] The present invention provides a method for preparing a core-spun yarn, comprising:

[0021] (1) preparing polyimide raw sliver and flame retardant acrylic raw sliver from pretreated polyimide fiber and pretreated flame retardant acrylic fiber, and mixing and roving the raw sliver to obtain blended roving;

[0022] (2) The blended roving and core yarn are prepared into core-spun yarn through siro spinning process; wherein the core yarn is modified basalt fiber.

[0023] The polyimide fiber pretreated in step (1) is a polyimide fiber pretreated with a polyether nonionic oil agent; the flame retardant acrylic fiber pretreated with a polyether nonionic oil agent; wherein the oil agent concentration is 0.5% to 1.5%, and the treatment is carried out in a 60°C oven for 3 hours.

[0024] The polyimide fiber pretreated in step (1) and the flame-retardant acrylic fiber pretreated are respectively cleaned and carded to produce polyimide sliver and flame-retardant acrylic sliver.

[0025] In step (1), the raw yarns are mixed: a polyimide raw yarn and a flame retardant acrylic raw yarn are pre-mixed in a mass ratio of (30-60): (70-40), and then mixed twice to obtain a certain dry weight of the raw yarn;

[0026] Furthermore, the drawing process uses an 8-fiber, 3-pass drawing process. This 8-fiber, 3-pass drawing process can process more fibers simultaneously, improving production efficiency. This multi-pass drawing process ensures uniform distribution of the outer fiber, reduces ends down, improves yarn strength, and reduces energy consumption and costs.

[0027] In step (1), the roving is prepared into blended roving by a roving machine, and the roving twist is 3 to 5 T / 10 cm.

[0028] The preparation of the modified basalt fiber comprises: subjecting the basalt fiber to two-stage low-temperature plasma treatment;

[0029] Furthermore, the basalt fiber is placed in a vacuum reaction chamber for plasma treatment, which is divided into two stages: high-energy physical etching and low-energy chemical activation:

[0030] The first stage (high-energy physical etching): using argon plasma, power 120-200W, time 3-5min, pressure 20-40Pa, quartz tube reactor speed set to 15-20r / min, the fiber surface is physically etched by high-energy ion bombardment;

[0031] The second stage (low-energy chemical activation): switch to oxygen plasma, power 50-120W, time 3-5min, pressure 20-40Pa, quartz tube reactor speed set to 15-20r / min, and introduce oxygen-containing functional groups (-COOH, -OH) through free radical oxidation.

[0032] After the plasma treatment, the samples were taken out and immediately stored in a vacuum bag and used within 3 to 5 days.

[0033] The "low temperature" in the low-temperature plasma technology of the present invention does not refer to absolute low temperature (such as sub-zero temperature), but is relative to traditional high-temperature plasma (such as arc plasma). The gas temperature of low-temperature plasma is 30-100°C, while the gas temperature of high-temperature plasma is as high as thousands of degrees Celsius.

[0034] Furthermore, the basalt fiber is pre-treated and then plasma treated, wherein the pre-treatment includes: ultrasonic treatment of the basalt fiber in an acetone solution for 1-6 hours, followed by water washing and drying to remove surface oil and coating;

[0035] The drying step is 60° C. for 8-12 hours.

[0036] The siro spinning process in step (2) includes: core yarn feeding, roving drafting, composite twisting and tension control.

[0037] Furthermore, in step (2), the core yarn of the siro spinning process is fed and twisted together with the drawn blended roving to form a core-sheath covering structure.

[0038] The core yarn is fed directly into the front roller without passing through the drafting zone.

[0039] Roving drafting parameters: the feeding distance between two rovings is 6-12mm; the total drafting ratio of the roving is 33-40 times, and the drafting ratio of the back zone is 1.0-3.0 times;

[0040] The roving fineness is 450-800tex;

[0041] Twist parameters: The twist on the machine is 800-1500T / m, and the twist coefficient is set to 350-450;

[0042] Tension control: The core yarn tension adjustment range is 5~15cN, and the tension sensor provides real-time feedback to the servo motor for closed-loop control (error ±0.5cN).

[0043] The present invention provides an application of the core-spun yarn in the fields of fire protection and high-temperature industry.

[0044] The core-spun yarn described in the present invention includes a core layer and a sheath layer: the core layer is composed of basalt fiber filaments treated with low-temperature plasma, the linear density is 0.5-2.5 dtex, the single-filament tensile strength is ≥2000 MPa, and the surface is treated in two stages: argon high-energy etching (120-200W, 3-5min) and oxygen low-energy activation (50-120W, 3-5min), the roughness Ra is ≥1.2μm, the oxygen content is increased by ≥12%, and the interface bonding is significantly enhanced; the sheath layer is blended by polyimide fiber (LOI 33%-38%) and flame-retardant acrylic fiber (LOI 28%-30%) in a mass ratio of (30-60):(70-40), and a uniform mixed structure is formed through oil pretreatment, three-pass drawing and roving process. The core layer and the skin layer are compounded through the siro spinning process, the core yarn tension is closed-loop controlled (5-15cN, ±0.5cN), double roving is fed (spacing 6-12mm) and high twist (800-1500T / m) is combined to form a dense core-sheath coating.

[0045] The present invention provides a method for preparing the core-spun yarn: first, the surface of the basalt fiber filaments is etched by a staged low-temperature plasma technology, and then the outer layer fibers are coated on the outer layer of the core yarn through a spinning process to prepare the core-spun yarn. In the method for preparing the core-spun yarn provided by the present invention, the surface of the basalt fiber filaments is etched by a low-temperature plasma technology. After the treatment, the surface roughness of the basalt fiber is increased, and the number of oxygen-containing groups increases, which is conducive to enhancing the cohesion between the surface-inert basalt fiber and the polyimide fiber and the flame-retardant acrylic fiber, thereby improving the structural stability of the core-spun yarn. The use of sirospinning technology eliminates the need to draft the core layer yarn, reduces the deformation and damage of the basalt fiber during processing, and achieves high-quality fiber coating through the spinning process, thereby improving the overall performance of the core-spun yarn.

[0046] The core-spun yarn provided by the present invention combines basalt inorganic filaments and organic fibers, with basalt fiber filaments serving as core yarns, thereby improving the load-bearing capacity of the core-spun yarn. Polyimide fiber is used as one of the outer covering fibers, so that the core-spun yarn has excellent flame retardant properties. The addition of flame-retardant acrylic fiber improves the spinnability and wear resistance of the core-spun yarn. The use of siro core-spun spinning technology gives the outer covering fibers a stable and tight structure, reduces the relative movement between the fibers, and reduces the risk of damage to the basalt fibers. With its excellent physical and chemical properties, the core-spun yarn can be applied to a variety of application fields, including but not limited to firefighting uniforms, military equipment, high-temperature filter materials, safety belts and ropes, etc., providing a high-performance material option for these fields.

[0047] Beneficial effects

[0048] Through the innovative combination of core-spun yarn structure design and basalt fiber surface modification technology, the present invention systematically solves key problems such as easy shrinkage and weak interface bonding of flame-retardant yarn, while achieving coordinated optimization of performance, cost and processing efficiency.

[0049] This invention utilizes surface-modified basalt fiber filaments as the core layer and a polyimide / flame-retardant acrylic blended yarn as the sheath layer, creating a core-sheath structure. The core basalt fiber's extremely low thermal shrinkage significantly outperforms traditional flame-retardant polyester or aramid, preventing fabric collapse in high-temperature environments. The sheath layer is a blend of polyimide and low-cost flame-retardant acrylic, reducing raw material costs.

[0050] The fiber surface is oxidized, etched, and roughened using a phased low-temperature plasma treatment. The modified basalt fiber surface oxygen content increases, strengthening the chemical bond with the cortical polymer. The improved surface roughness enhances the mechanical engagement between the fiber and the blended components, resulting in a lower yarn breakage rate than untreated basalt fiber.

[0051] The core-spun yarn of the present invention has a limiting oxygen index of ≥38%, no dripping phenomenon in a vertical burning test, a high temperature (300°C×5min) heat shrinkage rate of ≤5%, and a flame retardant performance retention rate of ≥90% after 20 standard washes. DETAILED DESCRIPTION

[0052] Example 1

[0053] This embodiment provides a core-spun yarn, and the preparation method is as follows:

[0054] Step (1), before being blended, the polyimide fiber and the flame retardant acrylic fiber are respectively pretreated with a polyether nonionic oil (oil concentration 0.5% to 1.5%) and treated in an oven at 60° C. for 3 hours;

[0055] Step (2), cleaning and carding the pretreated polyimide fiber and flame retardant acrylic fiber respectively to prepare polyimide raw sliver and flame retardant acrylic raw sliver;

[0056] Step (3), pre-stretching the pretreated polyimide fiber and the flame-retardant acrylic fiber in a mass ratio of 3:7, then blending twice, and using an 8-strand three-pass drawing process to produce a blended sliver with a set mass ratio;

[0057] Step (4): feeding the drawn sliver into a roving machine to prepare roving, with a twist of 3 to 5 T / 10 cm.

[0058] Step (5): feeding the two blended rovings into a spinning frame, and using siro spinning technology to cover the outer fiber on the outside of the basalt fiber modified by low-temperature plasma through a spinning process to obtain a core-spun yarn, wherein the mass ratio of basalt fiber to blended outer fiber is 5:5.

[0059] Step (6), Siro spinning process: in the roving drafting process, the feeding spacing between the two rovings is 8 mm; the total drafting multiple of the roving is 35 times, and the drafting multiple of the back zone is 1.5 times; in the twisting process, the upper twist is 800 T / m, and the twist coefficient is set to 350; in the tension control process, the core yarn tension adjustment range is 7 cN.

[0060] Step (7), low-temperature plasma treatment of basalt fiber: First, in an argon plasma atmosphere, set the power to 180W, the pressure to 20Pa, and the speed of the quartz tube reactor to 20r / min, and treat the basalt fiber for 5 minutes. Then, switch to oxygen plasma, set the power to 120W, the pressure to 20Pa, and the speed of the quartz tube reactor to 20r / min, and treat the basalt fiber for 5 minutes.

[0061] Example 2

[0062] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 1, except that in step (3), the pre-treated polyimide fiber and the flame-retardant acrylic fiber are pre-stretched in a mass ratio of 4:6, and then blended twice. The drawing process adopts 8-strand three-pass drawing to prepare a blended sliver with a set mass ratio;

[0063] Example 3

[0064] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 1, except that in step (3), the pre-treated polyimide fiber and the flame-retardant acrylic fiber are pre-stretched at a mass ratio of 5:5, and then blended twice. The drawing process adopts 8-strand three-pass drawing to prepare a blended sliver with a set mass ratio;

[0065] Example 4

[0066] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 1, except that in step (3), the pre-treated polyimide fiber and the flame-retardant acrylic fiber are pre-stretched in a mass ratio of 6:4, and then blended twice. The drawing process adopts 8-strand three-pass drawing to prepare a blended sliver with a set mass ratio;

[0067] Example 5

[0068] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 1, except that in step (5), two strands of blended roving are fed into a spinning frame, and the outer fiber is coated on the outside of the basalt fiber modified by low-temperature plasma through a spinning process using siro spinning technology to obtain the core-spun yarn. The mass ratio of basalt fiber to blended outer fiber is 3:7.

[0069] Example 6

[0070] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 1, except that in step (5), two strands of blended roving are fed into a spinning frame, and the outer fiber is coated on the outside of the basalt fiber modified by low-temperature plasma through a spinning process using siro spinning technology to obtain the core-spun yarn. The mass ratio of basalt fiber to blended outer fiber is 7:3.

[0071] Example 7

[0072] This embodiment provides a core-spun yarn. The specific preparation method is compared with Example 4, except that the step of treating the surface of the basalt fiber with low-temperature plasma is to use argon plasma treatment and then switch to oxygen plasma, set the power to 80W, the pressure to 20Pa, the speed of the quartz tube reactor to 20r / min, and treat the basalt fiber for 5min.

[0073] Example 8

[0074] This embodiment provides a core-spun yarn. The specific preparation method is compared with Example 4, except that the step of treating the surface of the basalt fiber with low-temperature plasma is to use argon plasma treatment and then switch to oxygen plasma, set the power to 50W, the pressure to 20Pa, the speed of the quartz tube reactor to 20r / min, and treat the basalt fiber for 5min.

[0075] Example 9

[0076] This embodiment provides a core-spun yarn. The specific preparation method is compared with Example 7, except that the step of treating the surface of the basalt fiber with low-temperature plasma is to use argon plasma treatment and then switch to oxygen plasma, set the power to 80W, the pressure to 20Pa, the speed of the quartz tube reactor to 20r / min, and treat the basalt fiber for 3min.

[0077] Example 10

[0078] This embodiment provides a core-spun yarn. The specific preparation method is compared with Example 9, except that the step of treating the surface of the basalt fiber with low-temperature plasma is to use argon plasma treatment conditions, set 180W power, 20Pa pressure, quartz tube reactor speed of 20r / min, and treat the basalt fiber for 3min.

[0079] Example 11

[0080] This embodiment provides a core-spun yarn. The specific preparation method is compared with Example 10, except that the step of treating the surface of the basalt fiber with low-temperature plasma is to use argon plasma treatment conditions, set 120W power, 20Pa pressure, quartz tube reactor speed of 20r / min, and treat the basalt fiber for 3min.

[0081] Example 12

[0082] This embodiment provides a core-spun yarn. The specific preparation method is different from that of Example 4, except that when the surface of the basalt fiber is treated with low-temperature plasma, there is no oxygen plasma treatment step.

[0083] Example 13

[0084] This embodiment provides a core-spun yarn. The specific preparation method is different from that of Example 4, except that when the surface of the basalt fiber is treated with low-temperature plasma, there is no argon plasma treatment step.

[0085] Example 14

[0086] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 4, except that in the siro spinning process, during the roving drafting process, the feeding spacing between the two rovings is 8 mm; the total drafting multiple of the roving is 40 times, and the drafting multiple of the rear zone is 1.5 times; in the twisting process, the upper twist is 800 T / m, and the twist coefficient is set to 350; in the tension control process, the core yarn tension adjustment range is 7 cN.

[0087] Example 15

[0088] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 4, except that in the siro spinning process, during the roving drafting process, the feeding spacing between the two rovings is 8 mm; the total drafting multiple of the roving is 35 times, and the drafting multiple of the rear zone is 2.5 times; in the twisting process, the upper twist is 800 T / m, and the twist coefficient is set to 350; in the tension control process, the core yarn tension adjustment range is 7 cN.

[0089] Example 16

[0090] This embodiment provides a core-spun yarn. The specific preparation method is compared with Example 14, except that in the siro spinning process, during the roving drafting process, the feeding spacing between the two rovings is 12 mm; the total drafting multiple of the roving is 40 times, and the drafting multiple of the rear zone is 1.5 times; in the twisting process, the upper twist is 800 T / m, and the twist coefficient is set to 350; in the tension control process, the core yarn tension adjustment range is 7 cN.

[0091] Example 17

[0092] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 4, except that in the siro spinning process, during the roving drafting process, the feeding spacing between the two rovings is 8 mm; the total drafting multiple of the roving is 35 times, and the drafting multiple of the rear zone is 1.5 times; in the twisting process, the upper twist is 1000 T / m, and the twist coefficient is set to 350; in the tension control process, the core yarn tension adjustment range is 7 cN.

[0093] Example 18

[0094] This embodiment provides a core-spun yarn. The specific preparation method is compared with that of Example 4, except that in the siro spinning process, during the roving drafting process, the feeding spacing between the two rovings is 8 mm; the total drafting multiple of the roving is 35 times, and the drafting multiple of the rear zone is 1.5 times; in the twisting process, the upper twist is 800 T / m, and the twist coefficient is set to 350; in the tension control process, the core yarn tension adjustment range is 12 cN.

[0095] Sources of main raw materials and related parameters:

[0096] Basalt fiber is a continuous filament purchased from Zhejiang Shijin Basalt Fiber Co., Ltd., with a linear density of 0.5-2.5 dtex, a single-filament tensile strength of ≥2000 MPa, an elongation at break ≤3%, and is non-flammable.

[0097] The polyimide fiber was purchased from Jiangsu Aoshen New Materials Co., Ltd., with a linear density of 0.6-1.67 dtex, a breaking strength of 3.0-5.2 cN / dtex, an elongation at break of 16-17%, and a limiting oxygen index of 33-38%. The flame-retardant acrylic fiber was purchased from Jilin Chemical Fiber Group, with a linear density of 1.5-6.0 dtex, a breaking strength of 2.5-4.0 cN / dtex, an elongation at break of 25-35%, and a limiting oxygen index of 28-30%.

[0098] Performance results data involves testing standards and methods:

[0099] Hairiness: The hairiness test was conducted using a YG171L yarn hairiness tester in accordance with the standard FZ / T 01086 Textile yarn hairiness determination method - Projection counting method.

[0100] Limiting oxygen index: Siro-spun yarn is made into cotton strips with a specification of 2.0g*10cm in weight and uniform length. The limiting oxygen index test is carried out using a limiting oxygen index tester in accordance with the standard "GB / T5454 Textiles - Determination of Combustion Performance - Oxygen Index Method".

[0101] Vertical burning: Siro-spun yarn was made into slivers of uniform length and weight (2.0g*10cm). The slivers were then tested in a vertical combustion apparatus according to GB / T 5455 Textiles - Burning performance - Determination of vertical direction damage length, smoldering and afterflaming time.

[0102] High temperature thermal shrinkage: refer to the "GB / T 6505 Test method for thermal shrinkage of chemical fiber filaments (after treatment)" standard test.

[0103] Example test results

[0104]

Claims

1. A core-spun yarn, characterized in that: The core-spun yarn comprises a core layer and a skin layer, wherein the core layer is modified basalt fiber; and the skin layer is a blended yarn of polyimide fiber and flame-retardant acrylic fiber.

2. The core-spun yarn according to claim 1, characterized in that: The mass ratio of the core layer to the skin layer is (30-70):(70-30); the blending mass ratio of the polyimide fiber to the flame-retardant acrylic fiber is (30-60):(70-40).

3. The core-spun yarn according to claim 1, characterized in that: The modified basalt fiber is a continuous filament with a linear density of 0.5 to 2.5 dtex; The polyimide fiber has a linear density of 0.6 to 1.67 dtex; the flame-retardant acrylic fiber has a linear density of 1.5 to 6.0 dtex.

4. The core-spun yarn according to claim 1, characterized in that: The oxygen content of the surface of the modified basalt fiber is increased by ≥12%, and the roughness Ra is ≥1.2 μm.

5. A method for preparing the core-spun yarn according to any one of claims 1 to 4, comprising: (1) Pretreated polyimide fiber and pretreated flame retardant acrylic fiber are made into polyimide raw sliver and flame retardant acrylic raw sliver, the two raw slivers are mixed to obtain cooked sliver, and then subjected to a roving process to obtain a blended roving for preparing the outer yarn of the core-spun yarn; (2) preparing core-spun yarn by siro-spinning the blended roving and the core yarn; The core yarn is modified basalt fiber.

6. The preparation method according to claim 5, characterized in that: The polyimide fiber pretreated in step (1) is a polyimide fiber pretreated with a polyether nonionic oil agent; the flame retardant acrylic fiber pretreated with a polyether nonionic oil agent is a flame retardant acrylic fiber pretreated with a polyether nonionic oil agent.

7. The preparation method according to claim 5, characterized in that: The preparation of the modified basalt fiber comprises: The basalt fibers were subjected to two stages of plasma treatment; In the first stage, argon plasma was used with a power of 120-200 W, a time of 3-5 min, a pressure of 20-40 Pa, and a quartz tube reactor speed of 15-20 r / min; The second stage: switch to oxygen plasma, power 50-120W, time 3-5min, pressure 20-40Pa, and the speed of the quartz tube reactor is set to 15-20r / min.

8. The preparation method according to claim 5, characterized in that: The siro spinning process in step (2) includes: core yarn feeding, roving drafting, composite twisting and tension control.

9. The preparation method according to claim 5, characterized in that: The core yarn is fed directly to the front roller without passing through the drafting zone; Roving drafting parameters: Roving fineness is 450-800tex; the feeding distance between two rovings is 6-12mm; the total drafting ratio of the roving is 33-40 times, and the drafting ratio of the back zone is 1.0-3.0 times; Twist parameters: The twist on the machine is 800-1500T / m, and the twist coefficient is set to 350-450; Tension control: The core yarn tension adjustment range is 5~15cN.

10. Use of the core-spun yarn according to claim 1 in the fields of fire protection and high-temperature industry.

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