Preparation process of flame-retardant anti-dripping fiber

Abstract

The invention discloses a preparation process of flame-retardant anti-dripping fibers. The preparation process comprises the following steps: mixing raw materials, efficiently filtering, extruding a melt, cooling and curing step by step, and post-treating to prepare the flame-retardant anti-dripping fibers. In the raw material mixing stage, the flame retardant adding proportion and the mixing technology are accurately controlled, it is guaranteed that the flame retardant is evenly dispersed in a polymer matrix, and efficient flame retardant performance is provided for fibers; in the efficient filtering link, a full-automatic filter screen replacing device is used for regularly removing impurities to ensure that the melt is pure and uniform; the internal stress and defects of the fibers are effectively reduced in the melt extrusion and gradient cooling curing process, and the fiber forming quality is improved; and drafting and heat setting treatment in the post-treatment stage further optimizes the fiber structure and enhances the mechanical property. The finally prepared flame-retardant and anti-dripping fiber has excellent flame-retardant and anti-dripping performance and stable physical and mechanical properties, and the preparation method realizes remarkable improvement of the performance of the flame-retardant and anti-dripping fiber through multi-link collaborative optimization.

Description

Technical Field

[0001] The invention relates to the field of flame-retardant and anti-melt-drip fibers, and in particular to a preparation process of flame-retardant and anti-melt-drip fibers. Background Art

[0002] Flame-retardant, anti-drip fibers are widely used in aerospace, electronics, transportation, and other fields. They effectively prevent the spread of flames and suppress the generation of molten droplets, making them crucial for improving material safety. The existing process for preparing flame-retardant, anti-drip fibers typically involves mixing a halogen-, phosphorus-, or nitrogen-based flame retardant with a fiber polymer matrix, followed by spinning and post-processing to produce the finished product.

[0003] However, traditional preparation processes have numerous shortcomings. The lack of effective melt filtration methods before spinning means that residual impurities and unmelted particles in the polymer mixture can clog the spinneret and cause fiber breakage during the spinning process, affecting the surface quality and mechanical properties of the fibers. Although filters are sometimes used, they often clog, preventing the melt from passing through the effective filtration area, leading to product defects (such as unmelted particles in fiber products). Conventional cooling methods often use a single temperature, which cannot achieve gradient cooling of the fibers. This causes internal stress in the fibers during the curing process due to the internal and external temperature differences, resulting in defects such as deformation and cracking, which in turn affects the flame retardant and anti-melt droplet properties and dimensional stability of the fibers. Furthermore, the filters in traditional processes require manual and regular replacement, which is cumbersome and prone to interrupting production, reducing production efficiency.

[0004] Therefore, there is an urgent need for a flame-retardant and anti-melt droplet fiber preparation process that can accurately filter the melt, gradiently cool the fiber, and continuously produce it, so as to overcome the shortcomings of the existing technology and improve product quality and production efficiency. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems in the background technology and provide a preparation process of flame retardant and anti-drip fiber.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: A preparation process of flame-retardant anti-drip fiber, comprising the following steps: S1, raw material mixing: drying the PET resin at 120-130°C for 5-7 hours to remove moisture; weighing all raw materials according to the formula ratio, placing them in a high-speed mixer, and mixing them at a speed of 1000 rpm for 12 minutes to ensure that the materials are fully and evenly mixed; S2, high-efficiency filtration: The uniformly mixed polymer mixture is fed into a screw extruder and heated to 220-320°C to fully melt it. Immediately after extrusion, it is connected to a fully automatic filter replacement filtration device for filtration. By replacing the filter, impurities are removed efficiently, continuous filtration is ensured, and melt uniformity is improved; S3, melt extrusion, extruding the polymer melt after high-efficiency filtration through a spinneret to form a melt stream; S4, step-by-step cooling and solidification, the melt stream passes through the slow cooling device for gradient cooling, which promotes uniform solidification of the fiber, reduces stress and defects, improves the stability of flame retardant and anti-melt droplet properties, and forms nascent fibers; S5, post-processing, stretching and heat-setting the as-spun fiber at a stretching ratio of 2 to 5 times and a stretching temperature of 80 to 120° C.; and heat-setting at a temperature of 180 to 220° C. for 5 to 15 minutes to obtain a flame-retardant and anti-drip fiber.

[0007] The present invention utilizes a fully automated filter replacement system during efficient filtration to regularly remove impurities and ensure a pure and uniform melt. The melt extrusion and gradient cooling solidification process effectively reduces internal fiber stress and defects, improving fiber molding quality. Post-processing steps such as drafting and heat setting further optimize the fiber structure and enhance mechanical properties. The resulting flame-retardant, anti-drip fiber combines excellent flame-retardant and anti-drip properties with stable physical and mechanical properties. This preparation method achieves significant improvements in the performance of flame-retardant, anti-drip fibers through the coordinated optimization of multiple steps.

[0008] Preferably, the fully automatic filter replacement device includes a fixed plate, a reel, a pressing and clamping mechanism, a pulling mechanism, and a laser cutting mechanism. The fixed plate is provided with a filter guide groove from left to right, and a guide hole is provided on the top of the fixed plate. The reel is provided in the inlet direction of the filter guide groove, the pressing and clamping mechanism is provided in the outlet direction of the filter guide groove, the pulling mechanism is provided behind the pressing and clamping mechanism, and the laser cutting mechanism is provided above the pressing and clamping mechanism for cutting the filter.

[0009] There is also a differential pressure sensor and two pressure interfaces, which are connected to the filter inlet and outlet respectively to measure the pressure difference between the upstream and downstream of the filter. When the pressure difference rises above the set threshold, it indicates that the filter is clogged.

[0010] The present invention winds the filter mesh on the reel through the reel, passes the filter mesh from the fixed plate through the filter mesh guide groove and is fixed by the pressing and clamping mechanism, and allows the melt to flow into the filter mesh through the guide hole. When the pressure difference sensor detects that the filter mesh is clogged, the mesh replacement is automatically triggered, and the filter mesh located in the guide hole is pulled out by the pulling mechanism, and the new filter mesh is pulled out from the reel, passed through the filter mesh guide groove and fixed on the pressing and clamping mechanism. The clogged filter mesh part is cut by the laser cutting mechanism, thereby completing the automatic and rapid replacement of the filter mesh without stopping the machine, achieving continuous production, precise filtration, and reducing manual intervention, avoiding the unfiltered melt from entering the product due to delays in manual mesh changing, and at the same time, in the production of flame retardant and anti-melting dripping fibers, it can effectively filter the agglomerated particles of the flame retardant, prevent the appearance of "hard points" on the fiber surface or the formation of cavities inside, improve the smoothness and mechanical properties of the fiber, filter impurities more accurately, and improve the purity of the product.

[0011] Preferably, the pressing and clamping mechanism includes a lower pressing block, an upper pressing block, a connecting plate, a pressing electric push rod, and a fixing frame. The fixing frame is fixed at the outlet of the filter guide groove. Several lower pressing blocks are linearly arrayed on the fixing frame and are located below the filter guide groove. A clamping opening for easy clamping is provided between two adjacent lower pressing blocks. An upper pressing block is provided above each lower pressing block. The upper pressing block is fixed on the connecting plate. The push rod end of the pressing electric push rod is fixedly connected to the connecting plate, and the motor end of the pressing electric push rod is fixed on the fixing frame.

[0012] The present invention can clamp the filter soft net through the lower pressing block and the upper pressing block, and the clamping openings between adjacent lower pressing blocks are convenient for the clamping operation of the clamping claws of the pulling mechanism.

[0013] Preferably, the pulling and pulling mechanism includes a linear slide rail, a slider, a connecting bar, and a clamping claw structure. The two linear slide rails are arranged on both sides of the lower pressure block and fixed on the fixed frame. The slider is slidably arranged on the linear slide rail, the connecting bar is arranged between the two sliders, and several clamping claw structures are fixed on the connecting bar, and each clamping claw structure corresponds to a clamping port.

[0014] The present invention drives the slider to move on the linear slide rail to drive the clamping claw structure to approach the clamping port to clamp the soft filter net. After clamping, the filter net can be driven to be pulled out, thereby realizing the function of automatic pulling out.

[0015] Preferably, the clamping jaw structure includes an upper clamping jaw, a lower clamping jaw, a sliding rod, a sliding rod electric push rod, and a fixed block, the fixed block is fixed on the connecting bar, a sliding groove is provided in the fixed block, the sliding rod is arranged in the sliding groove, the sliding rod electric push rod is arranged in the sliding groove, and its push rod end is fixed at the end of the sliding rod, the front end of the fixed block is provided with an extension plate, the rear end of the lower clamping jaw is provided with a first mounting plate, the rear end of the upper clamping jaw is provided with two second mounting plates, the sliding rod is hinged to the first mounting plate, the first mounting plate is hinged to the second mounting plate, and the extension plate is hinged to the second mounting plate.

[0016] The present invention drives the slide bar to move back and forth in the slide groove through the reciprocating motion of the slide bar electric push rod, thereby driving the upper clamping jaw and the lower clamping jaw to open and close.

[0017] Preferably, a pressure ring is provided above the guide hole of the fixed plate, and a space for the filter screen to pass through is left between the bottom of the pressure ring and the fixed plate. A tightening rod is provided on the top of the pressure ring, and a pressure ring electric push rod is provided on the top of the tightening rod. A limiting groove is provided at the position of the tightening rod at the top of the pressure ring, and a magnet is provided in the limiting groove. The tightening rod can be made of metal.

[0018] The present invention drives the pressure ring to press the filter screen through the pressure ring electric push rod, so that the melt can only flow through the diversion hole. When the filter screen needs to be replaced, the pressure ring electric push rod drives the pressure ring to rise, releasing the pressure on the filter screen, so that the filter soft screen can move freely.

[0019] The present invention enables the pressure ring and the pressing rod to be detachably connected through the magnet, so that the pressure ring can be replaced with pressure rings of different sizes according to needs.

[0020] Preferably, rubber pads are provided on the inner sides of the upper clamping jaw and the lower clamping jaw to enhance the clamping force.

[0021] The laser cutting mechanism includes a slide rail and a laser head, so that the slide rail can drive the laser head to move, thereby completing the cutting, so that the filter screen part withdrawn from the guide hole can be removed for later collection.

[0022] Preferably, the slow cooling device is a cooling coil, a water inlet is provided at the bottom of the cooling coil, a water outlet is provided at the top of the cooling coil, a heat dissipation pipe is provided on the outer wall of the cooling coil, and a plurality of heat dissipation fins are provided on the heat dissipation pipe.

[0023] In the present invention, the coolant enters from the bottom water inlet and flows from bottom to top along the cooling coil, so that the temperature of the upper layer of the cooling coil is higher than that of the lower layer. When the melt stream passes through the cooling coil, the cooling coil absorbs heat, causing the melt stream to cool down slowly. From the perspective of dispersibility, the liquid time of the melt is extended, the flame retardant is promoted to be evenly dispersed, agglomeration is reduced, the reaction of synergistic flame retardant systems such as phosphorus-nitrogen is enhanced, and the carbon layer structure is optimized; in terms of crystallization regulation, it is conducive to the formation of stable α crystal form, improves crystallinity, and reduces crystal defects. In terms of fiber structure, it can reduce the thickness of the skin layer, balance the skin-core performance, and reduce the risk of delamination and fracture droplets caused by structural differences; it can also enhance the interfacial bonding between the flame retardant and the matrix and anchor the melt.

[0024] The present invention accelerates cooling efficiency through the heat dissipation pipe and the heat dissipation fin.

[0025] Preferably, the water outlet is connected to a radiator, and the outlet of the cooler is connected to the water inlet of the cooling coil, so that the coolant can be circulated.

[0026] In summary, the beneficial effects of the present invention are: 1. The present invention utilizes a fully automatic filter replacement device to regularly remove impurities during the high-efficiency filtration process, ensuring the purity and uniformity of the melt. The melt extrusion and gradient cooling solidification process effectively reduces internal stress and defects in the fiber, improving the fiber molding quality. The drafting and heat setting treatments in the post-processing stage further optimize the fiber structure and enhance the mechanical properties. The resulting flame-retardant and anti-melting drip fiber has both excellent flame-retardant and anti-melting dripping properties and stable physical and mechanical properties. This preparation method achieves significant improvements in the performance of flame-retardant and anti-melting dripping fibers through multi-step collaborative optimization. 2. The present invention winds the filter mesh on the reel through the reel, passes the filter mesh from the fixed plate through the filter mesh guide groove and is fixed by the pressing and clamping mechanism, and allows the melt to flow into the filter mesh through the guide hole. When the pressure differential sensor detects that the filter mesh is clogged, the mesh replacement is automatically triggered, and the filter mesh located in the guide hole is pulled out by the pulling mechanism, and the new filter mesh is pulled out from the reel, passed through the filter mesh guide groove and fixed on the pressing and clamping mechanism. The clogged filter mesh part is cut by the laser cutting mechanism, thereby completing the automatic and rapid replacement of the filter mesh without stopping the machine, achieving continuous production, precise filtration, and reducing manual intervention, avoiding the unfiltered melt from entering the product due to delays in manual mesh changing, and effectively filtering the flame retardant agglomerated particles in the production of flame retardant and anti-drip fibers, preventing the appearance of "hard spots" on the fiber surface or the formation of cavities inside, improving the fiber smoothness and mechanical properties, and filtering impurities more accurately, thereby improving the purity of the product; 3. In the present invention, the coolant enters from the bottom water inlet and flows from bottom to top along the cooling coil, making the temperature of the upper layer of the cooling coil higher than that of the lower layer. As the melt stream passes through the cooling coil, the cooling coil absorbs heat, causing the melt stream to cool slowly. From the perspective of dispersibility, this prolongs the liquid state time of the melt, promotes the uniform dispersion of the flame retardant, reduces agglomeration, enhances the reaction of synergistic flame retardant systems such as phosphorus and nitrogen, and optimizes the carbon layer structure. In terms of crystallization control, it is conducive to the formation of a stable α crystal form, improves crystallinity, reduces crystal defects, can thin the skin thickness, balance skin-core properties, and reduce the risk of delamination and fracture of droplets due to structural differences. It can also enhance the interfacial bonding between the flame retardant and the substrate and anchor the melt. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the fully automatic filter replacement filter device of the present invention; Figure 2 Schematic diagram of the pressing and clamping mechanism and the pulling mechanism of the present invention; Figure 3 is a schematic diagram of a fixing plate of the present invention; Figure 4 is a schematic cross-sectional view of a fixing plate of the present invention; Figure 5 This invention Figure 4 An enlarged schematic diagram of point A; Figure 6 is a schematic diagram of the clamping jaw structure of the present invention; Figure 7 is a schematic cross-sectional view of the clamping jaw structure of the present invention; Figure 8 It is a schematic diagram of the clamping structure of the present invention without the upper clamping jaw and the fixing block; Figure 9 is a schematic diagram of the upper clamping jaw of the present invention; Figure 10 is a schematic diagram of a slow cooling device of the present invention; Figure 11 Schematic diagram of the cooling coil of the present invention.

[0028] 1. Automatic filter replacement device; 11. Fixed plate; 12. Reel; 13. Pressing and clamping mechanism; 14. Pulling mechanism; 15. Laser cutting mechanism; 110. Filter guide groove; 111. Diversion hole; 131. Lower pressure block; 132. Upper pressure block; 133. Connecting plate; 134. Pressing electric push rod; 135. Fixed frame; 136. Clamping port; 141. Linear guide rail; 142. Slider; 143. Connecting strip; 16. Clamping jaw structure; 161. Upper clamping jaw; 162. Lower clamping jaw; 163, sliding rod; 164, sliding rod electric push rod; 165, fixing block; 167, extension plate; 168, first mounting plate; 169, second mounting plate; 17, pressure ring; 175, filter screen passage space; 171, tightening rod; 172, pressure ring electric push rod; 173, limiting groove; 174, magnet; 160, rubber gasket; 2, slow cooling device; 21, cooling coil; 210, water inlet; 211, water outlet; 212, heat pipe; 213, heat sink. DETAILED DESCRIPTION

[0029] The following specific embodiments are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the embodiments as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

[0030] The present invention will be described in detail below with reference to the accompanying drawings using embodiments.

[0031] Example 1

[0032] A preparation process of flame-retardant anti-drip fiber, comprising the following steps: S1, raw material mixing: drying the PET resin at 120°C for 5 hours to remove moisture; weighing all raw materials according to the formula ratio, placing them in a high-speed mixer, and mixing them at a speed of 1000 rpm for 12 minutes to ensure that the materials are fully and evenly mixed; S2, high-efficiency filtration, put the mixed polymer mixture into the screw extruder, heat and melt it and extrude it, and immediately connect it. The fully automatic filter replacement filter device 1 performs filtration, and by replacing the filter, it can effectively remove impurities, ensure continuous filtration, and improve melt uniformity; S3, melt extrusion, extruding the polymer melt after high-efficiency filtration through a spinneret to form a melt stream; S4, step-by-step cooling and solidification, the melt stream passes through the slow cooling device 2 for gradient cooling, which promotes uniform solidification of the fiber, reduces stress and defects, improves the stability of flame retardant and anti-melt droplet properties, and forms nascent fibers; S5, post-processing, stretching and heat-setting the as-spun fiber, with a stretching ratio of 2 and a stretching temperature of 80° C.; and a heat-setting temperature of 180° C. for 5 minutes, to obtain a flame-retardant and anti-melting fiber.

[0033] Flame retardant and anti-drip PET balanced formula

[0034] like Figure 1 As shown, the fully automatic filter replacement device 1 includes a fixed plate 11, a reel 12, a pressing and clamping mechanism 13, a pulling mechanism 14, and a laser cutting mechanism 15. The fixed plate 11 is provided with a filter guide groove 110 from left to right, and a guide hole 111 is provided on the top of the fixed plate 11. The reel 12 is arranged in the inlet direction of the filter guide groove 110, the pressing and clamping mechanism 13 is arranged in the outlet direction of the filter guide groove 110, the pulling mechanism 14 is arranged behind the pressing and clamping mechanism 13, and the laser cutting mechanism 15 is arranged above the pressing and clamping mechanism 13 for cutting the filter.

[0035] like Figure 2-Figure 9As shown, the pressing and clamping mechanism 13 includes a lower pressing block 131, an upper pressing block 132, a connecting plate 133, a pressing electric push rod 134, and a fixing frame 135. The fixing frame 135 is fixed at the outlet of the filter guide groove 110. A plurality of the lower pressing blocks 131 are linearly arrayed on the fixing frame 135 and are located below the filter guide groove 110. A clamping opening 136 for easy clamping is provided between two adjacent lower pressing blocks 131. An upper pressing block 132 is provided above each lower pressing block 131. The upper pressing block 132 is fixed on the connecting plate 133. The push rod end of the pressing electric push rod 134 is connected to the connecting plate 133. The motor end of the pressing electric push rod 134 is fixed on the fixing frame 135. The pulling mechanism 14 includes a linear slide 141, a slider 142, a connecting bar 143, and a clamping claw structure 16. The two linear slides 141 are provided on both sides of the lower pressing block 131 and are fixed on the fixing frame 135. The slider 142 is slidably provided on the linear slide 141. The connecting bar 143 is provided between the two sliders 142. Several clamping claw structures 16 are fixed on the connecting bar 143. Each clamping claw structure 16 corresponds to a clamping port 136. The clamping claw structure 16 includes an upper clamping claw 161 and a lower clamping claw 16. 2. Slide rod 163, slide rod electric push rod 164, fixed block 165, the fixed block 165 is fixed on the connecting bar 143, a slide groove 166 is provided in the fixed block 165, the slide rod 163 is provided in the slide groove 166, the slide rod electric push rod 164 is provided in the slide groove 166, and its push rod end is fixed to the end of the slide rod 163, the front end of the fixed block 165 is provided with an extension plate 167, the rear end of the lower clamping jaw 162 is provided with a first mounting plate 168, the rear end of the upper clamping jaw 161 is provided with two second mounting plates 169, the slide rod 163 is hinged to the first mounting plate 168, the first mounting plate 168 is hinged to the second mounting plate 169, and the extension plate 167 is hinged to the second mounting plate 169. A pressure ring 17 is provided above the guide hole 111 of the fixed plate 11, and a filter mesh passing space 175 is left between the bottom of the pressure ring 17 and the fixed plate 11. A tightening rod 171 is provided on the top of the pressure ring 17, and a pressure ring electric push rod 172 is provided on the top of the tightening rod 171. A limiting groove 173 is provided at the position of the tightening rod 171 at the top of the pressure ring 17, and a magnet 174 is provided in the limiting groove 173. The inner sides of the upper clamping jaw 161 and the lower clamping jaw 162 are provided with rubber pads 160.

[0036] like Figure 10-11As shown, the slow cooling device 2 is a cooling coil 21, the bottom of the cooling coil 21 is provided with a water inlet 210, the top of the cooling coil 21 is provided with a water outlet 211, the outer wall of the cooling coil 21 is provided with a heat dissipation pipe 212, and the heat dissipation pipe 212 is provided with a plurality of heat dissipation fins 213. The water outlet 211 is connected to a radiator, and the outlet of the radiator is connected to the water inlet 210 of the cooling coil 21.

[0037] Working principle: Figure 1-11 As shown, the working principle is as follows: after the raw materials are mixed, they are put into a screw extruder for heating and melting. The molten mixture is extruded by the extruder, and then efficiently filtered through the guide hole 111 of the filter device 1 with fully automatic filter replacement. The polymer melt after high efficiency filtration is extruded through the spinneret to form a melt stream. The melt stream passes through the cooling coil 21, so that the melt stream is slowly cooled, reducing stress and defects, improving the stability of flame retardant and anti-melting droplet performance, forming nascent fibers, and the nascent fibers are stretched and heat-set at a stretching ratio of 2 to 5 times and a stretching temperature of 80 to 120°C; the heat-setting temperature is 180 to 220°C and the time is 5 to 15 minutes to obtain flame retardant and anti-melting droplet fibers. During the entire operation process, when the pressure difference rises and exceeds the set threshold, the screen change is automatically triggered, the sliding rod electric push rod 164 moves forward, driving the sliding rod 163 to move forward, so that the upper clamping jaw 161 and the lower clamping jaw 162 are in an open state, pressing the electric push rod 134 to lift upward, and the clamping jaw structure 16 moves toward the clamping mouth 136 through the linear slide rail 141. After moving into place, the sliding rod electric push rod 164 moves backward, driving the sliding rod 163 to move backward, so that the upper clamping jaw 161 and the lower clamping jaw 162 are in a closed state, thereby pulling out the filter soft net on the clamping mouth until the new filter net is pulled out from the reel and passes through the filter guide. Move to the groove to the clamping port 136, stop the pulling action, press the electric push rod 134 downward so that the lower pressure block 131 and the upper pressure block 132 clamp the soft filter screen, and the blocked filter screen part is cut by the laser cutting mechanism 15, thereby completing the automatic and rapid replacement of the filter screen without stopping, continuous production, precise filtration, and reducing manual intervention, avoiding the unfiltered melt from entering the product due to delays in manual screen changing, and finally obtaining the flame retardant and anti-melting dripping fiber, which has both excellent flame retardant and anti-melting dripping properties and stable physical and mechanical properties. This preparation method achieves significant improvement in the performance of flame retardant and anti-melting dripping fibers through multi-link collaborative optimization.

[0038] Example 2

[0039] Different from Example 1, a preparation process of a flame retardant and drip-resistant fiber includes the following steps: S1, raw material mixing: drying the PET resin at 125°C for 6 hours to remove moisture; weighing all raw materials according to the formula ratio, placing them in a high-speed mixer, and mixing them at a speed of 1000 rpm for 12 minutes to ensure that the materials are fully and evenly mixed; S2, high-efficiency filtration, the mixed polymer mixture is fed into the screw extruder, and immediately connected to the fully automatic filter replacement filtration device 1 for filtration after extrusion, by replacing the filter screen to efficiently remove impurities, ensure continuous filtration, and improve melt uniformity; S3, melt extrusion, extruding the polymer melt after high-efficiency filtration through a spinneret to form a melt stream; S4, step-by-step cooling and solidification, the melt stream passes through the slow cooling device 2 for gradient cooling, which promotes uniform solidification of the fiber, reduces stress and defects, improves the stability of flame retardant and anti-melt droplet properties, and forms nascent fibers; S5, post-processing, stretching and heat-setting the as-spun fiber at a stretching ratio of 2 to 5 times and a stretching temperature of 100° C.; and heat-setting at a temperature of 200° C. for 10 minutes to obtain a flame-retardant and anti-melting fiber.

[0040] Highly flame retardant formula

[0041] Example 3 Different from Example 1, a preparation process of a flame retardant and drip-resistant fiber includes the following steps: S1, mixing raw materials: drying the PET resin at 130°C for 7 hours to remove moisture; weighing all raw materials according to the formula ratio, placing them in a high-speed mixer, and mixing them at a speed of 1000 rpm for 12 minutes to ensure that the materials are fully and evenly mixed; S2, high-efficiency filtration, the mixed polymer mixture is fed into the screw extruder, and immediately connected to the fully automatic filter replacement filtration device 1 for filtration after extrusion, by replacing the filter screen to efficiently remove impurities, ensure continuous filtration, and improve melt uniformity; S3, melt extrusion, extruding the polymer melt after high-efficiency filtration through a spinneret to form a melt stream; S4, step-by-step cooling and solidification, the melt stream passes through the slow cooling device 2 for gradient cooling, which promotes uniform solidification of the fiber, reduces stress and defects, improves the stability of flame retardant and anti-melt droplet properties, and forms nascent fibers; S5, post-processing, stretching and heat-setting the as-spun fiber, with a stretching ratio of 5 times and a stretching temperature of 120° C.; and a heat-setting temperature of 220° C. for 15 minutes, to obtain a flame-retardant and anti-melting fiber.

[0042] High strength anti-drip formula

[0043] Comparative Example Different from Example 1, during the process, the fiber with the same formula was prepared by using the traditional manual screen changing and single-stage cooling process.

[0044] 3. Performance Test and Results

[0045] 4. Results Analysis 1. Flame retardant performance: Example 2 has the highest limiting oxygen index, the shortest vertical combustion damage length, and the best flame retardant effect due to the significant increase in the flame retardant ratio. Example 3 has a lower flame retardant dosage, and the LOI and damage length performance are relatively weak.

[0046] 2. Mechanical properties: Example 3 has the best breaking strength and elongation due to its higher PET resin content; Example 2 has a certain negative impact on the mechanical properties due to the high flame retardant filling.

[0047] 3. Anti-drip performance: All three examples achieved a no-drip effect, indicating that the anti-drip additive in the formulation design played an effective role.

[0048] In the comparative example, a fiber with the same formulation produced using a traditional manual screen changing and single-stage cooling process achieved a droplet rate of 15 drops / 10s, an LOI of 30%, and a breaking strength of 3.2 cN / dtex. In the embodiments of the present invention, the use of the fully automatic screen changing filter device effectively reduces the introduction of impurities and production interruptions. The slow cooling device (particularly its gradient cooling method) refines the fiber structure and optimizes the distribution of the flame retardant. These improvements significantly enhance the fiber's anti-droplet performance and mechanical properties.

Claims

1. A process for preparing flame-retardant and anti-drip fiber, characterized in that: The following steps are involved: S1, raw material mixing, drying the PET resin at 120-130℃ for 5-7 hours to remove moisture; weighing all raw materials according to the formula ratio, placing them in a high-speed mixer to fully and evenly mix the materials; S2, high-efficiency filtration, feeding the uniformly mixed polymer mixture into the screw extruder, and immediately connecting it to the fully automatic filter replacement filter device (1) for filtration after extrusion; S3, melt extrusion, extruding the polymer melt after high-efficiency filtration through a spinneret to form a melt stream; S4, step-by-step cooling and solidification, the melt stream passes through the slow cooling device (2) for gradient cooling, promoting uniform solidification of the fiber to form primary fibers; S5, post-processing, stretching and heat-setting the as-spun fiber at a stretching ratio of 2 to 5 times and a stretching temperature of 80 to 120° C.; and heat-setting at a temperature of 180 to 220° C. for 5 to 15 minutes to obtain a flame-retardant and anti-drip fiber.

2. The process for preparing a flame retardant and drip-resistant fiber according to claim 1, characterized in that: The fully automatic filter screen replacement device (1) comprises a fixed plate (11), a reel (12), a pressing and clamping mechanism (13), a pulling and drawing mechanism (14), and a laser cutting mechanism (15). The fixed plate (11) is provided with a filter screen guide groove (110) from left to right, and a guide hole (111) is provided at the top of the fixed plate (11). The reel (12) is provided in the inlet direction of the filter screen guide groove (110), the pressing and clamping mechanism (13) is provided in the outlet direction of the filter screen guide groove (110), the pulling and drawing mechanism (14) is provided behind the pressing and clamping mechanism (13), and the laser cutting mechanism (15) is provided above the pressing and clamping mechanism (13) for cutting the filter screen.

3. The process for preparing a flame retardant and drip-resistant fiber according to claim 2, characterized in that: The pressing and clamping mechanism (13) includes a lower pressing block (131), an upper pressing block (132), a connecting plate (133), a pressing electric push rod (134), and a fixing frame (135). The fixing frame (135) is fixed at the outlet of the filter guide groove (110). A plurality of the lower pressing blocks (131) are linearly arrayed on the fixing frame (135) and are located below the filter guide groove (110). A clamping opening (136) for facilitating clamping is provided between two adjacent lower pressing blocks (131). An upper pressing block (132) is provided above each lower pressing block (131). The upper pressing block (132) is fixed on the connecting plate (133). The push rod end of the pressing electric push rod (134) is fixedly connected to the connecting plate (133), and the motor end of the pressing electric push rod (134) is fixed on the fixing frame (135).

4. The process for preparing a flame-retardant and drip-resistant fiber according to claim 3, characterized in that: The pulling mechanism (14) includes a linear slide rail (141), a slider (142), a connecting bar (143), and a clamping claw structure (16). The two linear slide rails (141) are arranged on both sides of the lower pressing block (131) and fixed on the fixing frame (135). The slider (142) is slidably arranged on the linear slide rail (141). The connecting bar (143) is arranged between the two sliders (142). A plurality of the clamping claw structures (16) are fixed on the connecting bar (143), and each clamping claw structure (16) corresponds to a clamping opening (136).

5. The process for preparing a flame retardant and drip-resistant fiber according to claim 4, characterized in that: The clamping jaw structure (16) includes an upper clamping jaw (161), a lower clamping jaw (162), a slide rod (163), a slide rod electric push rod (164), and a fixed block (165). The fixed block (165) is fixed on the connecting bar (143). A slide groove (166) is provided in the fixed block (165). The slide rod (163) is arranged in the slide groove (166). The slide rod electric push rod (164) is arranged in the slide groove (166), and its push rod end is fixed on the slide rod. (163), the front end of the fixed block (165) is provided with an extension plate (167), the rear end of the lower clamping jaw (162) is provided with a first mounting plate (168), the rear end of the upper clamping jaw (161) is provided with two second mounting plates (169), the sliding rod (163) is hinged to the first mounting plate (168), the first mounting plate (168) is hinged to the second mounting plate (169), and the extension plate (167) is hinged to the second mounting plate (169).

6. The process for preparing a flame-retardant and drip-resistant fiber according to claim 2, characterized in that: A pressure ring (17) is provided above the guide hole (111) of the fixed plate (11), and a filter mesh passing space (175) is reserved between the bottom of the pressure ring (17) and the fixed plate (11). A tightening rod (171) is provided on the top of the pressure ring (17), and a pressure ring electric push rod (172) is provided on the top of the tightening rod (171). A limiting groove (173) is provided at the top of the pressure ring (17) at a position corresponding to the tightening rod (171), and a magnet (174) is provided in the limiting groove (173).

7. The process for preparing a flame-retardant and drip-resistant fiber according to claim 5, characterized in that: The inner sides of the upper clamping jaw (161) and the lower clamping jaw (162) are both provided with rubber pads (160).

8. The process for preparing a flame-retardant and drip-resistant fiber according to claim 2, characterized in that: The slow cooling device (2) comprises a cooling coil (21), wherein a water inlet (210) is provided at the bottom of the cooling coil (21), and a water outlet (211) is provided at the top of the cooling coil (21).

9. The process for preparing a flame-retardant and drip-resistant fiber according to claim 8, characterized in that: A heat dissipation pipe (212) is provided on the outer side wall of the cooling coil (21), and a plurality of heat dissipation fins (213) are provided on the heat dissipation pipe (212).

10. The process for preparing a flame-retardant and drip-resistant fiber according to claim 9, characterized in that: The water outlet (211) is connected to a radiator, and the outlet of the radiator is connected to the water inlet (210) of the cooling coil (21).

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