Preparation method for flame-retardant and Anti-dripping polyester fiber

Abstract

A preparation method for a flame-retardant and anti-dripping polyester fiber. A flame-retardant and anti-dripping polyester fiber is obtained by mixing polyester, a flame-retardant polyester masterbatch (A or B) and an anti-dripping agent in the mass ratio of 65-75:15-25:2-20 and then performing melt spinning; the preparation process of the flame-retardant polyester masterbatch A comprises: in the polyester preparation process, adding a phosphorus-based flame retardant into a system in an esterification stage, and adding a nitrogen-based flame retardant and a silicon-based flame retardant into the system in a polycondensation stage to obtain the flame-retardant polyester masterbatch A; and the preparation process of the flame-retardant polyester masterbatch B comprises: carrying out melt blending on polyester and IFR to obtain the flame-retardant polyester masterbatch B. The flame-retardant and anti-dripping polyester fiber prepared by means of the technical solution has good flame retardance, anti-dripping properties and spinnability, and a fiber product prepared from a fiber having a special-shaped cross section also has good comfort.

Description

Preparation method of flame-retardant and droplet-suppressing polyester fiber

[0001] This application claims the benefit of Chinese patent application No. 2023111275878, filed on September 4, 2023. This application incorporates the entirety of the aforementioned Chinese patent application. Technical Field

[0002] The invention belongs to the field of functional polyester fibers and relates to a method for preparing flame-retardant and droplet-suppressing polyester fibers. Background Art

[0003] Large-scale industrial production of polyester in China began in the 1980s. Since then, the polyester industry has flourished as its applications have expanded. From 2014 to 2018, annual polyester production in China reached nearly 40 million tons, reaching 65 million tons in 2022, accounting for over 80% of China's total chemical fiber output. With the development of the polyester industry, demand for functionalized polyester has become increasingly prominent. Flame retardancy, as a key indicator of fire safety, plays a crucial role in polyester applications. According to statistics, between 2012 and 2021, a total of 1.324 million residential fires occurred nationwide, resulting in approximately 11,634 deaths, 6,738 injuries, and direct economic losses of 7.77 billion yuan. Approximately 20% of residential fires and 50% of deaths were related to textile ignition. During the combustion process, secondary ignition caused by molten droplets poses a significant risk to human life and property. With the advancement of science and technology and society, people are paying more and more attention to environmental issues. When selecting flame retardants, in addition to high flame retardancy, environmental friendliness is also a key concern. Traditional halogenated flame retardants have been banned by countries and organizations such as the European Union and Japan. Therefore, while improving the flame retardancy of polyester fibers, the development and use of highly effective, environmentally friendly, and non-toxic flame retardants is of great practical significance.

[0004] In the existing technology, there are three main ways to modify polyester fibers to be flame retardant: copolymerization, blending, and finishing. While these three methods bring flame retardancy, people also put forward new requirements for the comfort and health of fabrics. The preparation of flame retardant and droplet-suppressing polyester fibers has also become one of the important directions of their functional modification research.

[0005] Patent CN114230720A discloses an additive with both flame retardant and anti-drip properties, a preparation method, and a composition thereof. The patent first prepares a core-layer fluoropolymer dispersion. Using the fluoropolymer dispersion as a seed, a vinyl monomer, an initiator, a chain transfer agent, and a surfactant are added, and the temperature is raised to polymerize to produce a core-shell structure polymer emulsion. This emulsion is then subjected to coagulation, centrifugation, and drying to produce a core-shell structure polymer. This core-shell polymer is then sulfonated and washed with deionized water until neutral. After solid-liquid separation, the polymer is dried to obtain a sulfonated core-shell polymer powder. This additive is a new, environmentally friendly, and highly efficient flame retardant and anti-drip additive with excellent flame retardant and anti-drip properties. Adding 0.05 to 1.50 parts to polycarbonate, ABS, its alloys, and polyester can achieve a flame retardancy rating of UL-94 V-0. However, the patent's preparation process is complex, the additive is only applicable to films and plastic products, and it significantly affects component pressure and yarn continuity during the spinning process, making it unsuitable for industrial polyester fiber production.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing flame-retardant and drip-suppressing polyester fibers, so as to achieve the characteristics of flame retardancy, drip resistance and spinnability.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] The flame retardant and drip-suppressing polyester fiber is prepared by mixing polyester, a flame retardant polyester masterbatch and a drip-suppressing agent and then performing melt spinning to obtain the flame retardant and drip-suppressing polyester fiber.

[0010] The flame retardant polyester masterbatch is flame retardant polyester masterbatch A or flame retardant polyester masterbatch B;

[0011] The preparation process of flame-retardant polyester masterbatch A is as follows: during the polyester preparation process, a phosphorus-based flame retardant is added to the system during the esterification stage, and a nitrogen-based flame retardant and a silicon-based flame retardant are added to the system during the polycondensation stage to obtain flame-retardant polyester masterbatch A;

[0012] The preparation process of flame retardant polyester masterbatch B is as follows: polyester and IFR (intumescent flame retardant) are melt-blended to obtain flame retardant polyester masterbatch B;

[0013] The phosphorus-based flame retardant is one or more of DDP ([(6-oxo-6H-dibenzo[c,e][1,2]oxaphosphorin-6-yl)methyl]succinic acid), ODOPB (10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide), and CEPPA (2-carboxyethylphenylphosphinic acid);

[0014] The nitrogen flame retardant is one or more of MCA (melamine cyanurate), KH550 (γ-aminopropyltriethoxysilane), and hexagonal boron nitride;

[0015] The silicon-based flame retardant is one or more of silicate, silicon dioxide and POSS;

[0016] The dripping inhibitor is one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride, tetrafluoroethylene-polyvinylidene fluoride copolymer, polyhexafluoropropylene, tetrafluoroethylene-polyhexafluoropropylene copolymer, tetrafluoroethylene-polyvinylidene fluoride-polyhexafluoropropylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, copolymer of tetrafluoroethylene and other copolymerizable olefin unsaturated monomers, sulfobutyl-β-cyclodextrin (SBE-β-CD), and potassium perfluorobutanesulfonate;

[0017] The mass ratio of polyester, flame retardant polyester masterbatch and drip inhibitor is 65-75:15-25:2-20;

[0018] The contents of phosphorus-based flame retardant, nitrogen-based flame retardant and silicon-based flame retardant in flame-retardant polyester masterbatch A are 0.5-1wt% (preferably 0.6wt%), 1-5wt% (preferably 2-3wt%) and 0.5-1wt% (preferably 0.5-0.7wt%), respectively; the content of IFR in flame-retardant polyester masterbatch B is 5-20wt% (preferably 15wt%).

[0019] The purpose of the present invention is to solve the problem that flame-retardant polyester fibers in the prior art cannot achieve flame retardancy, anti-melting dripping, and spinnability. The present invention solves the problem that flame-retardant polyester fibers in the prior art cannot achieve flame retardancy, anti-melting dripping, and spinnability by controlling the types, addition amounts, and addition methods of phosphorus-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, and anti-melting dripping agents. The specific principles are as follows:

[0020] The dripping inhibitor of the present invention is a sulfonic acid flame retardant or a fluorine flame retardant; when phosphorus flame retardants, nitrogen flame retardants, silicon flame retardants, and sulfonic acid flame retardants (or fluorine flame retardants) are simultaneously present in the system, during the combustion process, the phosphorus flame retardant copolymerized in the molecular chain breaks first due to the weak bond energy of PO, generating P· and PO· free radicals, which can combine with flammable free radicals in the air (such as alkane free radicals) to inhibit the continued occurrence of combustion. At the same time, the nitrogen flame retardant releases inert gases such as N2 in the gas phase, further diluting the concentration of the combustible gas, which is the flame retardant effect of the gas phase during the combustion process; in the condensed phase, the presence of the sulfonic acid flame retardant can catalyze the formation of polyester into carbon, covering the surface of the polymer, isolating heat and oxygen, and at the same time, the silicon flame retardant or the fluorine flame retardant can further enhance the strength and density of the carbon layer, and the isolation effect is further enhanced;

[0021] The present invention simultaneously adds phosphorus-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, and sulfonic acid-based flame retardants (or fluorine-based flame retardants) to make the polyester have excellent flame retardant properties and anti-dripping properties. Therefore, the added amount of phosphorus-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, and sulfonic acid-based flame retardants (or fluorine-based flame retardants) does not need to be too high to obtain ideal flame retardant and anti-dripping effects. The added amount of phosphorus-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, and sulfonic acid-based flame retardants (or fluorine-based flame retardants) is relatively low, which is conducive to the smooth progress of spinning.

[0022] Phosphorus-based flame retardants are reactive flame retardants that participate in the molecular chain polymerization process. Therefore, they are added during the polymerization process. The remaining flame retardants and melt drop inhibitors are mainly dispersed in the melt in the form of doping. If too much is added, it is easy to cause agglomeration and affect spinning. Multiple flame retardants can play a synergistic flame retardant role in the system, effectively reducing the amount added and promoting spinning formation.

[0023] As the preferred technical solution:

[0024] In the method for preparing the flame-retardant and drip-suppressing polyester fiber, the mass ratio of polyester, flame-retardant polyester masterbatch, and drip-suppressing agent is 75:20:5, or 70:20:10, or 65:20:15.

[0025] In the preparation method of the flame retardant and drip-suppressing polyester fiber as described above, the polyester, flame retardant polyester masterbatch and drip-suppressing agent are all dried before mixing, the drying temperature is 116-120°C (preferably 120°C), the drying time is about 14 hours, and the moisture content after drying is less than 100ppm (preferably 80-90ppm).

[0026] The preparation method of the flame-retardant and droplet-suppressing polyester fiber as described above, the preparation steps of the flame-retardant polyester masterbatch A are as follows:

[0027] Ethylene glycol and terephthalic acid are beaten and mixed, and a phosphorus-based flame retardant is added to the system;

[0028] Under nitrogen or inert gas protection, raise the system temperature from 150°C to 280°C within 30 minutes, and then keep the temperature for 1.5 to 2.5 hours;

[0029] Add nitrogen-based flame retardant and silicon-based flame retardant to the system, raise the temperature to 295°C, and react for 2 to 3 hours (preferably 2.7 to 3 hours) under a vacuum degree of less than 50 Pa (preferably 30 Pa, 40 Pa) to obtain flame-retardant polyester masterbatch A.

[0030] The preparation method of the flame-retardant and droplet-suppressing polyester fiber as described above, the melt spinning process includes: melt extrusion by a screw extruder → spinning → ring-blown air cooling → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → curling → oiling → relaxation heat setting → cutting.

[0031] The preparation method of the flame retardant and droplet-suppressing polyester fiber as described above, the process parameters of the melt spinning include: the temperature of each zone of the screw extruder is 265-290°C (preferably 265-288°C), the spinning box temperature is 275-290°C, the metering pump supply is 500-900g / min (preferably 860-880g / min), the annular air temperature is 25-30°C (preferably 26-28°C), the annular air inlet pressure is 500-800Pa (preferably 720-760Pa), the winding speed is 900-1100m / min (preferably 1000-1100m / min), the drawing temperature is 65±5°C (preferably 66-68°C), and the secondary drawing ratio is 3-4 times (preferably 3.3-3.6 times).

[0032] After the present invention adds phosphorus-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, and melt drip inhibitors to polyester through a specific addition method, the regularity of the polyester molecular chain decreases, which in turn affects the molecular weight and molecular weight distribution, specifically manifested as a change in rheological properties during the melt processing process, which places higher requirements on the processing temperature; the addition of the melt drip inhibitor will not only change the requirements for the filter screen in the spinneret assembly, but will also affect the crystallization properties of the molecular chain, and thus affect the annular blowing temperature and annular blowing inlet pressure. The present invention ensures that melt spinning can still proceed smoothly after adding phosphorus-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, and melt drip inhibitors to polyester by reasonably controlling the process parameters of melt spinning.

[0033] In the method for preparing the flame retardant and droplet-suppressed polyester fiber as described above, the temperatures of zones 1 to 6 of the screw extruder correspond to 265°C, 275°C, 280°C, 285°C, 280°C, and 275°C, respectively, and the spinning manifold temperature is 275°C; alternatively, the temperatures of zones 1 to 6 of the screw extruder correspond to 265°C, 270°C, 275°C, 280°C, 275°C, and 270°C, respectively, and the spinning manifold temperature is 270°C; alternatively, the temperatures of zones 1 to 6 of the screw extruder correspond to 270°C, 275°C, 280°C, 285°C, 280°C, and 275°C, respectively, and the spinning manifold temperature is 275°C.

[0034] In the method for preparing flame-retardant and droplet-suppressing polyester fibers as described above, the spinnerets in the spinneret used for spinning are one or more of the following shapes: a W-shape, a cross-shape, a trilobal shape, and a four-T shape (ie, four T letters are evenly distributed in the cross section).

[0035] Compared with conventional round polyester fibers, after being processed using the special-shaped process, the fibers also have better fluffiness, moisture absorption and perspiration-wicking properties, and higher gloss. While giving the fibers flame retardancy and anti-melting properties, it further improves and expands its application range in clothing, home textiles and industrial fields.

[0036] The preparation method of the flame-retardant and melt-drop inhibiting polyester fiber as described in any one of the above items, the fineness of the flame-retardant and melt-drop inhibiting polyester fiber is 0.89 to 22.22 dtex (preferably 1.11 - 22.22 dtex), the breaking strength is 5.3 to 6.0 cN / dtex (preferably 5.3 - 5.9 cN / dtex), the breaking elongation is 27.1 to 30.7% (preferably 27.3 - 29.5%), the crimp number is 10.4 - 11.9 per 25 mm, the crimp ratio is 11.1 - 12.7%, the LOI reaches more than 30% (preferably 30.1 - 32%), and no melt drops are generated during the combustion process. Beneficial effects:

[0037] (1) By controlling the types, addition amounts and addition methods of the phosphorus-based flame retardant, nitrogen-based flame retardant, silicon-based flame retardant and melt-drop inhibitor, the flame-retardant and melt-drop inhibiting polyester fiber prepared in the present invention has good flame retardancy, melt-drop resistance and good spinnability. The breaking strength of the prepared fiber can reach 5.8 cN / dtex, the breaking elongation is 28.9%, the LOI reaches more than 30%, and no melt drops are generated during the combustion process;

[0038] (2) Compared with the spinning process of conventional polyester fibers, the flame-retardant and melt-drop inhibiting polyester fiber can achieve good spinnability at a lower spinning temperature. The spinning temperature is reduced by 10 - 15 °C. The lower spinning temperature can not only delay the thermal degradation of the melt-drop inhibitor, but also effectively improve production efficiency and reduce costs;

[0039] (3) The copolymerization-blending modification method adopted in the present invention can effectively solve the problems of the decline in the mechanical properties of fibers caused by the addition of additives and the poor hand comfort of fiber products;

[0040] (4) The profiled cross-section design of the fiber in the present invention makes the fiber also have better bulkiness, moisture absorption and sweat discharge properties and higher gloss, which can further improve the comfort of the flame-retardant and melt-drop inhibiting fiber products. Moreover, the flame-retardant and melt-drop inhibiting property of the present invention can not only reduce the secondary injury caused by the combustion of clothing to the human body, but the profiled cross-section design improves the comfort performance of people using flame-retardant products and expands its application fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 is a schematic cross-sectional view of the flame-retardant and melt-drop inhibiting polyester fiber prepared when the spinneret hole used in the present invention is a king-shaped;

[0042] FIG. 2 is a schematic cross-sectional view of the flame-retardant and melt-drop inhibiting polyester fiber prepared when the spinneret hole used in the present invention is a cross-shaped;

[0043] FIG. 3 is a schematic cross-sectional view of the flame-retardant and melt-drop inhibiting polyester fiber prepared when the spinneret hole used in the present invention is a three-leaf-shaped;

[0044] FIG4 is a schematic cross-sectional view of the flame-retardant and droplet-suppressing polyester fiber prepared when the spinneret holes used in the present invention are four-T shaped. DETAILED DESCRIPTION

[0045] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0046] The following are manufacturers and trade names of raw materials in the examples:

[0047] IFR (intumescent flame retardant): A mixture of pentaerythritol (manufactured by Puyang Yongan Chemical Co., Ltd., brand 126-58-9), ammonium polyphosphate (manufactured by Shandong Zhongli Petrochemical Technology Co., Ltd., brand P37-N11), and melamine (manufactured by Shanghai Yuanye Biotechnology Co., Ltd., brand B21093) in a molar ratio of 1:1:1.

[0048] PET (polyethylene terephthalate): Manufacturer: Jiangsu Shenghong Technology and Trade Co., Ltd., brand: M02;

[0049] hBN (hexagonal boron nitride): manufacturer is Ark New Materials Co., Ltd., brand name is DL-7800A;

[0050] Silicate: The manufacturer is Qingdao Haiwan Group Co., Ltd., the brand is SSP-32;

[0051] POSS (cage-type polysilsesquioxane): manufacturer: Weibaiao (Beijing) Biotechnology Co., Ltd., brand name: MA0702;

[0052] PTFE (polytetrafluoroethylene): The manufacturer is Fuzhou Taipuda New Materials Co., Ltd., the brand is TPD-405B;

[0053] PVDF (polyvinylidene fluoride): manufacturer is Shanghai Huihang New Materials Co., Ltd., brand name is 3030-15;

[0054] XR (perfluorosulfonic acid resin): The manufacturer is Huainan Kedi Chemical Technology Co., Ltd., and the brand is superior;

[0055] F6 (polyhexafluoropropylene): Manufacturer: Zhejiang Juhua Co., Ltd. Fluoropoly Plant, brand number 6792-31-0;

[0056] FEP (tetrafluoroethylene-hexafluoropropylene copolymer): Manufacturer: Dongguan Longfeng Plastic Materials Co., Ltd., brand: NEOFLON NP-120;

[0057] ETFE (ethylene tetrafluoroethylene copolymer): manufactured by Shanghai Koraman Reagent Co., Ltd., brand ZY4051;

[0058] PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer): Manufacturer: Dongguan Suguang Plastic Materials Co., Ltd., brand: Generic PFA;

[0059] EPE (tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether): This substance is homemade. The specific preparation process is as follows: tetrafluoroethylene, hexafluoropropylene, perfluoroalkyl ethylene in a molar ratio of 1:1:1 and a catalyst (lithium diisopropylamine LDA) with a mass fraction of 0.1% are reacted at a temperature of 180°C and a pressure of 101 MPa for 3 hours to obtain tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether;

[0060] Sulfobutyl-β-cyclodextrin (SBE-β-CD): manufacturer: Zibo Qianhui Biotechnology Co., Ltd., brand name: 7585-39-9;

[0061] Potassium perfluorobutanesulfonate: The manufacturer is Fujian Shaowu Jintang Anshengqi Chemical Co., Ltd., and the brand name is 29420-49-3.

[0062] The following is the test method for the performance in each embodiment:

[0063] Curl number and curl rate: measured in accordance with GB / T 14338-2022.

[0064] Fineness: measured in accordance with GB / T 14336-2008.

[0065] Breaking strength: measured in accordance with GB / T 14337-2022.

[0066] Elongation at break: measured in accordance with GB / T 14337-2022.

[0067] LOI: Determined in accordance with FZ / T 50017-2011.

[0068] Moisture content: Determined in accordance with GB / T 6503-2017.

[0069] Melt dripping: During the determination of FZ / T 50017-2011, the number of times and drops of melt dripping within one minute is calculated.

[0070] Continued burning time: The continuous burning time of the fiber prepared in the embodiment after combustion occurs and the fire source is removed, in seconds.

[0071] Example 1

[0072] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0073] (1) Preparation of raw materials:

[0074] Phosphorus flame retardant: DDP;

[0075] Nitrogen flame retardant: MCA;

[0076] Silicon flame retardant: silicate;

[0077] Melt drip inhibitor: PTFE;

[0078] Ethylene glycol;

[0079] Terephthalic acid;

[0080] Protective gas: nitrogen or inert gas;

[0081] PET;

[0082] (2) preparing flame retardant polyester masterbatch A;

[0083] (2.1) Ethylene glycol and terephthalic acid were slurried and mixed at a molar ratio of 1.2:1, and a phosphorus-based flame retardant was added to the system;

[0084] (2.2) Under protective gas, increase the system temperature from 150°C to 280°C within 30 minutes and then maintain the temperature for 2 hours.

[0085] (2.3) Adding nitrogen-based flame retardant and silicon-based flame retardant to the system, raising the temperature to 295°C, and reacting under a vacuum degree of 40 Pa for 2.8 hours to obtain flame-retardant polyester masterbatch A;

[0086] The content of phosphorus flame retardant in the flame retardant polyester masterbatch A is 0.6 wt%, the content of nitrogen flame retardant is 2 wt%, and the content of silicon flame retardant is 0.6 wt%;

[0087] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0088] PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were dried at 120° C. to a moisture content of 80 ppm, and then the PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were mixed and melt-spun to obtain flame-retardant and melt-drip inhibitory polyester fibers; wherein the mass ratio of PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor was 75:15:10;

[0089] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0090] The process parameters of melt spinning include: the temperature of the first zone of the screw extruder is 265°C, the second zone is 275°C, the third zone is 280°C, the fourth zone is 285°C, the fifth zone is 280°C, the sixth zone is 275°C, the temperature of the spinning box is 275°C, the pump supply rate of the metering pump is 880 g / min, the temperature of the ring blower is 27°C, the inlet air pressure of the ring blower is 760 Pa, the winding speed is 1050 m / min, the drawing temperature is 67°C, and the secondary drawing ratio is 3.5 times;

[0091] The spinneret holes in the spinneret used for spinning are in the shape of a king character.

[0092] The cross-section of the finally obtained flame-retardant and melt-droplet-suppressing polyester fiber is shown in Figure 1. Its fineness is 1.56 dtex, the breaking strength is 5.8 cN / dtex, the breaking elongation is 28.3%, the crimp number is 10.4 per 25 mm, the crimp ratio is 11.6%, the LOI reaches 30.1%, the continuous burning time is 30 s and no melt droplets are generated during the burning process.

[0093] Comparative Example 1

[0094] The preparation method of the flame-retardant polyester fiber is basically the same as that of Example 1, except that: in step (1), no melt-droplet-suppressing agent is prepared; in step (3), no melt-droplet-suppressing agent is added, and the melt-droplet-suppressing agent is replaced by an equal mass of PET (the same as in Example 1).

[0095] The fineness of the finally obtained flame-retardant polyester fiber is 1.56 dtex, the breaking strength is 5.9 cN / dtex, the breaking elongation is 27.5%, the crimp number is 11.1 per 25 mm, the crimp ratio is 12.7%, the LOI reaches 29.8%, the continuous burning time is 55 s and melt droplets are generated during the burning process.

[0096] Comparing Comparative Example 1 with Example 1, it can be seen that when preparing the flame-retardant polyester fiber in Comparative Example 1, without using the melt-droplet-suppressing agent, it will cause the generation of molten dripping, which will further cause secondary ignition. This is because the polymer first undergoes melt degradation during the burning process, the melt fluidity increases, the melt not only plays a role in heat conduction during the flow process, but also further promotes the degradation of the polymer. At the same time, the flammable small molecules existing in the melt will also cause secondary ignition of the polymer.

[0097] Example 2

[0098] The preparation method of the flame-retardant and melt-droplet-suppressing polyester fiber is basically the same as that of Example 1, except that: the melt-droplet-suppressing agent is sulfobutyl-β-cyclodextrin.

[0099] The final flame retardant and droplet-suppressing polyester fiber has a fineness of 1.56 dtex, a breaking strength of 5.4 cN / dtex, an elongation at break of 27.7%, a crimp number of 11.1 / 25 mm, a crimp rate of 11.1%, an LOI of 31%, a continuous burning time of 48 seconds, and no droplets are generated during the combustion process.

[0100] Comparative Example 2

[0101] The preparation method of flame-retardant polyester fiber is basically the same as that of Example 2, except that: no drip inhibitor is prepared in step (1); no drip inhibitor is added in step (3), and the drip inhibitor is replaced by an equal mass of silicon-based flame retardant (same as in Example 1).

[0102] The final flame-retardant polyester fiber has a fineness of 1.56 dtex, a breaking strength of 5.6 cN / dtex, an elongation at break of 28.0%, an LOI of 30.8%, a continuous burning time of 63 s, and molten droplets are generated during the combustion process.

[0103] Comparative Example 3

[0104] The preparation method of flame-retardant polyester fiber is basically the same as that of Example 2, except that: silicon-based flame retardant is not prepared in step (1); silicon-based flame retardant is not added in step (2.3), and silicon-based flame retardant is replaced by an equal mass of melt drip inhibitor (same as in Example 2).

[0105] The final flame-retardant polyester fiber has a fineness of 1.56 dtex, a breaking strength of 5.5 cN / dtex, an elongation at break of 27.9%, an LOI of 30.9%, a continuous burning time of 77 seconds, and no droplets are generated during the combustion process.

[0106] By comparing Example 2, Comparative Example 2 and Comparative Example 3, it can be seen that the combined use of sulfonic acid flame retardants and silicon flame retardants is more effective than using them alone. This is because the presence of the sulfonic acid flame retardant can catalyze the formation of PET into carbon, covering the surface of the polymer and isolating heat and oxygen. At the same time, the silicon flame retardant can further enhance the strength and density of the carbon layer, further enhancing the insulation effect.

[0107] Example 3

[0108] The preparation method of the flame-retardant and drip-suppressing polyester fiber is basically the same as that of Example 1, except that the drip-suppressing agent is a mixture of polytetrafluoroethylene and sulfobutyl-β-cyclodextrin in a mass ratio of 1:1.

[0109] The final flame-retardant and droplet-suppressing polyester fiber has a fineness of 1.56 dtex, a breaking strength of 5.9 cN / dtex, an elongation at break of 29.5%, a crimp number of 11.8 / 25 mm, a crimp rate of 11.8%, and an LOI of 30.8%. The flame-retardant polyester fiber extinguishes itself when away from fire and no droplets are generated during the combustion process.

[0110] By comparing Example 1, Example 2 and Example 3, it can be seen that the combined use of fluorine-based flame retardants and sulfonic acid-based flame retardants is more effective than using them alone. This is because the presence of the sulfonic acid-based flame retardant can catalyze the formation of PET into carbon, covering the surface of the polymer and isolating heat and oxygen. At the same time, the fluorine-based flame retardant can further enhance the strength and density of the carbon layer, further enhancing the insulation effect.

[0111] Example 4

[0112] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0113] (1) Preparation of raw materials:

[0114] Phosphorus flame retardant: ODOPB;

[0115] Nitrogen flame retardant: MCA;

[0116] Silicon flame retardant: silicate;

[0117] Melting drip inhibitor: PVDF;

[0118] Ethylene glycol;

[0119] Terephthalic acid;

[0120] Protective gas: nitrogen or inert gas;

[0121] PET;

[0122] (2) preparing flame retardant polyester masterbatch A;

[0123] (2.1) Ethylene glycol and terephthalic acid were slurried and mixed at a molar ratio of 1.2:1, and a phosphorus-based flame retardant was added to the system;

[0124] (2.2) Under protective gas, increase the system temperature from 150°C to 280°C within 30 minutes and then maintain the temperature for 2 hours.

[0125] (2.3) Adding nitrogen-based flame retardant and silicon-based flame retardant to the system, raising the temperature to 295°C, and reacting under a vacuum degree of 40 Pa for 2.8 hours to obtain flame-retardant polyester masterbatch A;

[0126] The content of phosphorus flame retardant in the flame retardant polyester masterbatch A is 0.6 wt%, the content of nitrogen flame retardant is 2 wt%, and the content of silicon flame retardant is 0.6 wt%;

[0127] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0128] PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor are first dried at 120°C to a moisture content of 80 ppm, then the PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor are mixed and melt-spun to obtain flame-retardant and melt-drip inhibitory polyester fibers; wherein the mass ratio of PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor is 75:20:5;

[0129] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0130] The melt spinning process parameters include: screw extruder zone 1 temperature of 265°C, zone 2 temperature of 275°C, zone 3 temperature of 280°C, zone 4 temperature of 285°C, zone 5 temperature of 280°C, zone 6 temperature of 275°C, spinning box temperature of 275°C, metering pump supply of 880g / min, annular air temperature of 28°C, annular air inlet pressure of 720Pa, winding speed of 1100m / min, drafting temperature of 68°C, and secondary drafting ratio of 3.3 times;

[0131] The spinneret holes used in spinning are cross-shaped.

[0132] The cross-section of the flame-retardant and droplet-suppressing polyester fiber is shown in Figure 2. Its fineness is 1.89 dtex, breaking strength is 5.5 cN / dtex, breaking elongation is 27.9%, the number of crimps is 11.9 / 25mm, the crimp rate is 12.3%, the LOI reaches 30.6%, and no droplets are generated during the combustion process.

[0133] Example 5

[0134] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0135] (1) Preparation of raw materials:

[0136] IFR;

[0137] Melt drip inhibitor: FEP;

[0138] Protective gas: nitrogen or inert gas;

[0139] PET;

[0140] (2) preparing flame retardant polyester masterbatch B;

[0141] PET and IFR are melt-blended to obtain flame-retardant polyester masterbatch B;

[0142] The content of IFR in the prepared flame retardant polyester masterbatch B is 15wt%;

[0143] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0144] PET, flame retardant polyester masterbatch B, and melt drip inhibitor are first dried at 120°C to a moisture content of 90 ppm, then PET, flame retardant polyester masterbatch B, and melt drip inhibitor are mixed and melt-spun to obtain flame retardant and melt drip inhibitor polyester fibers; wherein the mass ratio of PET, flame retardant polyester masterbatch B, and melt drip inhibitor is 70:20:10;

[0145] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0146] The melt spinning process parameters include: screw extruder zone 1 temperature of 265°C, zone 2 temperature of 270°C, zone 3 temperature of 275°C, zone 4 temperature of 280°C, zone 5 temperature of 275°C, zone 6 temperature of 270°C, spinning box temperature of 270°C, metering pump supply of 870g / min, annular air temperature of 26°C, annular air inlet pressure of 750Pa, winding speed of 1000m / min, drafting temperature of 66°C, and secondary drafting ratio of 3.6 times;

[0147] The spinneret holes used in the spinning are trilobal.

[0148] The cross-section of the flame-retardant and droplet-suppressing polyester fiber is shown in Figure 3. Its fineness is 2.22 dtex, breaking strength is 5.5 cN / dtex, breaking elongation is 27.8%, the number of crimps is 11.2 / 25 mm, the crimp rate is 12.6%, the LOI reaches 32%, and no droplets are generated during the combustion process.

[0149] Example 6

[0150] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0151] (1) Preparation of raw materials:

[0152] IFR;

[0153] Melt drip inhibitor: F6;

[0154] Protective gas: nitrogen or inert gas;

[0155] PET;

[0156] (2) preparing flame retardant polyester masterbatch B;

[0157] PET and IFR are melt-blended to obtain flame-retardant polyester masterbatch B;

[0158] The content of IFR in the prepared flame retardant polyester masterbatch B is 15wt%;

[0159] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0160] PET, flame-retardant polyester masterbatch B, and drip inhibitor were dried at 120°C until the moisture content was 85 ppm, and then the PET, flame-retardant polyester masterbatch B, and drip inhibitor were mixed and melt-spun to obtain flame-retardant and drip-inhibited polyester fibers; wherein the mass ratio of PET, flame-retardant polyester masterbatch B, and drip inhibitor was 65:20:15;

[0161] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0162] The melt spinning process parameters include: screw extruder zone 1 temperature of 270°C, zone 2 temperature of 275°C, zone 3 temperature of 280°C, zone 4 temperature of 285°C, zone 5 temperature of 280°C, zone 6 temperature of 275°C, spinning box temperature of 275°C, metering pump supply of 860g / min, annular air temperature of 27°C, annular air inlet pressure of 740Pa, winding speed of 1100m / min, drafting temperature of 68°C, and secondary drafting ratio of 3.4 times;

[0163] The spinneret holes in the spinneret used for spinning are four-T shaped.

[0164] The cross-section of the flame-retardant and droplet-suppressing polyester fiber is shown in Figure 4. Its fineness is 3.33 dtex, breaking strength is 5.3 cN / dtex, breaking elongation is 27.4%, the number of crimps is 11.2 / 25 mm, the crimp rate is 12.6%, the LOI reaches 31.8%, and no droplets are generated during the combustion process.

[0165] Example 7

[0166] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0167] (1) Preparation of raw materials:

[0168] Phosphorus flame retardant: CEPPA;

[0169] Nitrogen flame retardant: KH550;

[0170] Silicon flame retardant: POSS;

[0171] Melt drip inhibitor: FEP;

[0172] Ethylene glycol;

[0173] Terephthalic acid;

[0174] Protective gas: nitrogen or inert gas;

[0175] PET;

[0176] (2) preparing flame retardant polyester masterbatch A;

[0177] (2.1) Ethylene glycol and terephthalic acid were slurried and mixed at a molar ratio of 1.2:1, and a phosphorus-based flame retardant was added to the system;

[0178] (2.2) Under protective gas, increase the system temperature from 150°C to 280°C within 30 minutes and then maintain the temperature for 2 hours.

[0179] (2.3) Add nitrogen-based flame retardant and silicon-based flame retardant to the system, raise the temperature to 295°C, and react for 3 hours under a vacuum degree of 40 Pa to obtain flame-retardant polyester masterbatch A;

[0180] The content of phosphorus flame retardant in the flame retardant polyester masterbatch A is 0.6 wt%, the content of nitrogen flame retardant is 2 wt%, and the content of silicon flame retardant is 0.6 wt%;

[0181] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0182] PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were dried at 120° C. to a moisture content of 80 ppm, and then the PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were mixed and melt-spun to obtain flame-retardant and melt-drip inhibitory polyester fibers; wherein the mass ratio of PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor was 75:15:10;

[0183] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0184] The melt spinning process parameters include: screw extruder zone 1 temperature of 268°C, zone 2 temperature of 278°C, zone 3 temperature of 283°C, zone 4 temperature of 288°C, zone 5 temperature of 283°C, zone 6 temperature of 278°C, spinning box temperature of 278°C, metering pump supply of 870g / min, annular air temperature of 27°C, annular air inlet pressure of 760Pa, winding speed of 1050m / min, drafting temperature of 67°C, and secondary drafting ratio of 3.5 times;

[0185] The spinneret holes used in spinning are cross-shaped.

[0186] The final flame retardant and droplet-suppressing polyester fiber has a fineness of 11.11 dtex, a breaking strength of 5.3 cN / dtex, an elongation at break of 27.5%, a crimp number of 11.2 / 25 mm, a crimp rate of 12.6%, an LOI of 31.9%, and no droplets are generated during the combustion process.

[0187] Example 8

[0188] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0189] (1) Preparation of raw materials:

[0190] Phosphorus flame retardant: DDP;

[0191] Nitrogen flame retardant: hBN;

[0192] Silicon flame retardant: POSS;

[0193] Melting drop inhibitor: PFA;

[0194] Ethylene glycol;

[0195] Terephthalic acid;

[0196] Protective gas: nitrogen or inert gas;

[0197] PET;

[0198] (2) preparing flame retardant polyester masterbatch A;

[0199] (2.1) Ethylene glycol and terephthalic acid in a molar ratio of 1.2:1 were slurried and mixed, and a phosphorus-based flame retardant was added to the system;

[0200] (2.2) Under protective gas, increase the system temperature from 150°C to 280°C within 30 minutes and then maintain the temperature for 2 hours.

[0201] (2.3) Adding nitrogen-based flame retardant and silicon-based flame retardant to the system, raising the temperature to 295°C, and reacting under a vacuum degree of 30 Pa for 2.8 hours to obtain flame-retardant polyester masterbatch A;

[0202] The content of phosphorus flame retardant in the flame retardant polyester masterbatch A is 0.6wt%, the content of nitrogen flame retardant is 3wt%, and the content of silicon flame retardant is 0.7wt%;

[0203] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0204] PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were dried at 120° C. to a moisture content of 90 ppm, and then the PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were mixed and melt-spun to obtain flame-retardant and melt-drip inhibitory polyester fibers; wherein the mass ratio of PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor was 70:15:15;

[0205] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0206] The melt spinning process parameters include: screw extruder zone 1 temperature of 266°C, zone 2 temperature of 276°C, zone 3 temperature of 281°C, zone 4 temperature of 286°C, zone 5 temperature of 281°C, zone 6 temperature of 276°C, spinning box temperature of 276°C, metering pump supply of 860g / min, annular air temperature of 28°C, annular air inlet pressure of 760Pa, winding speed of 1000m / min, drafting temperature of 66°C, and secondary drafting ratio of 3.6 times;

[0207] The spinneret holes used in the spinning are trilobal.

[0208] The final flame retardant and droplet-suppressing polyester fiber has a fineness of 13.32 dtex, a breaking strength of 5.3 cN / dtex, an elongation at break of 27.5%, a crimp number of 11.1 / 25 mm, a crimp rate of 11.7%, an LOI of 32.1%, and no droplets are generated during the combustion process.

[0209] Example 9

[0210] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0211] (1) Preparation of raw materials:

[0212] IFR;

[0213] Melting drop inhibitor: PFA;

[0214] Protective gas: nitrogen or inert gas;

[0215] PET;

[0216] (2) preparing flame retardant polyester masterbatch B;

[0217] PET and IFR are melt-blended to obtain flame-retardant polyester masterbatch B;

[0218] The content of IFR in the prepared flame retardant polyester masterbatch B is 15wt%;

[0219] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0220] PET, flame retardant polyester masterbatch B, and drip inhibitor are dried at 120°C to a moisture content of 85 ppm, and then the PET, flame retardant polyester masterbatch B, and drip inhibitor are mixed and melt-spun to obtain flame retardant and drip-inhibiting polyester fibers; wherein the mass ratio of PET, flame retardant polyester masterbatch B, and drip inhibitor is 65:15:20;

[0221] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0222] The melt spinning process parameters include: screw extruder zone 1 temperature of 265°C, zone 2 temperature of 275°C, zone 3 temperature of 280°C, zone 4 temperature of 285°C, zone 5 temperature of 280°C, zone 6 temperature of 275°C, spinning box temperature of 275°C, metering pump supply of 880g / min, annular air temperature of 26°C, annular air inlet pressure of 720Pa, winding speed of 1100m / min, drafting temperature of 68°C, and secondary drafting ratio of 3.4 times;

[0223] The spinneret holes in the spinneret used for spinning are four-T shaped.

[0224] The final flame retardant and droplet-suppressed polyester fiber has a fineness of 1.89 dtex, a breaking strength of 5.5 cN / dtex, an elongation at break of 28.7%, a crimp number of 11.1 / 25mm, a crimp rate of 11.7%, an LOI of 30.6%, and no droplets are generated during the combustion process.

[0225] Example 10

[0226] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0227] (1) Preparation of raw materials:

[0228] IFR;

[0229] Melt drip inhibitor: EPE;

[0230] Protective gas: nitrogen or inert gas;

[0231] PET;

[0232] (2) preparing flame retardant polyester masterbatch B;

[0233] PET and IFR are melt-blended to obtain flame-retardant polyester masterbatch B;

[0234] The content of IFR in the prepared flame retardant polyester masterbatch B is 15wt%;

[0235] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0236] PET, flame retardant polyester masterbatch B, and drip inhibitor are first dried at 120°C to a moisture content of 80 ppm, then the PET, flame retardant polyester masterbatch B, and drip inhibitor are mixed and melt-spun to obtain flame retardant and drip-inhibiting polyester fibers; wherein the mass ratio of PET, flame retardant polyester masterbatch B, and drip inhibitor is 65:25:10;

[0237] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0238] The melt spinning process parameters include: screw extruder zone 1 temperature of 268°C, zone 2 temperature of 278°C, zone 3 temperature of 283°C, zone 4 temperature of 288°C, zone 5 temperature of 283°C, zone 6 temperature of 278°C, spinning box temperature of 278°C, metering pump supply of 870g / min, annular air temperature of 27°C, annular air inlet pressure of 750Pa, winding speed of 1050m / min, drafting temperature of 67°C, and secondary drafting ratio of 3.5 times;

[0239] The spinneret holes used in spinning are cross-shaped.

[0240] The final flame retardant and droplet-suppressing polyester fiber has a fineness of 2.22dtex, a breaking strength of 5.5cN / dtex, an elongation at break of 28.6%, a crimp number of 10.9 / 25mm, a crimp rate of 12.2%, an LOI of 31.4%, and no droplets are generated during the combustion process.

[0241] Example 11

[0242] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0243] (1) Preparation of raw materials:

[0244] Phosphorus flame retardant: DDP;

[0245] Nitrogen flame retardant: KH550;

[0246] Silicon flame retardant: POSS;

[0247] Melting drop inhibitor: potassium perfluorobutanesulfonate;

[0248] Ethylene glycol;

[0249] Terephthalic acid;

[0250] Protective gas: nitrogen or inert gas;

[0251] PET;

[0252] (2) preparing flame retardant polyester masterbatch A;

[0253] (2.1) Ethylene glycol and terephthalic acid were slurried and mixed at a molar ratio of 1.2:1, and a phosphorus-based flame retardant was added to the system;

[0254] (2.2) Under protective gas, increase the system temperature from 150°C to 280°C within 30 minutes and then maintain the temperature for 2 hours.

[0255] (2.3) Adding nitrogen-based flame retardant and silicon-based flame retardant to the system, raising the temperature to 295°C, and reacting under a vacuum degree of 30 Pa for 2.9 hours to obtain flame-retardant polyester masterbatch A;

[0256] The content of phosphorus flame retardant in the flame retardant polyester masterbatch A is 0.6wt%, the content of nitrogen flame retardant is 3wt%, and the content of silicon flame retardant is 0.7wt%;

[0257] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0258] PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were dried at 120° C. to a moisture content of 90 ppm, and then the PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor were mixed and melt-spun to obtain flame-retardant and melt-drip inhibitory polyester fibers; wherein the mass ratio of PET, flame-retardant polyester masterbatch A, and melt-drip inhibitor was 70:15:15;

[0259] The melt spinning process includes: melt extrusion through screw extruder → spinning → cooling with annular air → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0260] The melt spinning process parameters include: screw extruder zone 1 temperature of 266°C, zone 2 temperature of 276°C, zone 3 temperature of 281°C, zone 4 temperature of 286°C, zone 5 temperature of 281°C, zone 6 temperature of 276°C, spinning box temperature of 276°C, metering pump supply of 860g / min, annular air temperature of 27°C, annular air inlet pressure of 740Pa, winding speed of 1000m / min, drafting temperature of 68°C, and secondary drafting ratio of 3.5 times;

[0261] The spinneret holes used in spinning are cross-shaped.

[0262] The final flame retardant and droplet-suppressing polyester fiber has a fineness of 22.22 dtex, a breaking strength of 5.3 cN / dtex, an elongation at break of 27.3%, a crimp number of 11.7 / 25 mm, a crimp rate of 11.9%, an LOI of 31.2%, and no droplets are generated during the combustion process.

[0263] Example 12

[0264] The preparation method of flame retardant and droplet-suppressing polyester fiber comprises the following steps:

[0265] (1) Preparation of raw materials:

[0266] Phosphorus flame retardant: a mixture of DDP and ODOPB in a mass ratio of 1:1;

[0267] Nitrogen flame retardant: a mixture of MCA and KH550 in a mass ratio of 1:1;

[0268] Silicon flame retardant: a mixture of silicate and silicon dioxide in a mass ratio of 1:1;

[0269] Melting drip inhibitor: a mixture of polytetrafluoroethylene and sulfobutyl-β-cyclodextrin in a mass ratio of 1:1;

[0270] Ethylene glycol;

[0271] Terephthalic acid;

[0272] Protective gas: nitrogen or inert gas;

[0273] PET;

[0274] (2) preparing flame retardant polyester masterbatch A;

[0275] (2.1) Ethylene glycol and terephthalic acid in a molar ratio of 1.2:1 were slurried and mixed, and a phosphorus-based flame retardant was added to the system;

[0276] (2.2) Under protective gas, increase the system temperature from 150°C to 280°C within 30 minutes and then maintain the temperature for 2 hours.

[0277] (2.3) Add nitrogen-based flame retardant and silicon-based flame retardant to the system, raise the temperature to 295°C, and react for 3 hours under a vacuum degree of 40 Pa to obtain flame-retardant polyester masterbatch A;

[0278] The content of phosphorus flame retardant in the flame retardant polyester masterbatch A is 0.6 wt%, the content of nitrogen flame retardant is 2.5 wt%, and the content of silicon flame retardant is 0.5 wt%;

[0279] (3) Preparation of flame retardant and droplet-suppressing polyester fibers;

[0280] First, dry PET, flame retardant polyester masterbatch A, and melt-dripping inhibitor at 120°C until their moisture contents are all 85 ppm. Then, mix PET, flame retardant polyester masterbatch A, and melt-dripping inhibitor and perform melt spinning to obtain flame retardant and melt-dripping resistant polyester fiber; among them, the mass ratio of PET, flame retardant polyester masterbatch A, and melt-dripping inhibitor is 65:15:20;

[0281] The process flow of melt spinning includes: melt extrusion by a screw extruder → spinning → cooling by ring blowing → winding → forming to obtain raw yarn → bundling of raw yarn → two-stage drawing → tension heat setting → crimping → oiling → relaxation heat setting → cutting;

[0282] The process parameters of melt spinning include: the temperature of the first zone of the screw extruder is 265°C, the temperature of the second zone is 275°C, the temperature of the third zone is 280°C, the temperature of the fourth zone is 285°C, the temperature of the fifth zone is 280°C, the temperature of the sixth zone is 275°C, the temperature of the spinning box is 275°C, the pump supply rate of the metering pump is 870 g / min, the temperature of the ring blowing is 26°C, the inlet air pressure of the ring blowing is 760 Pa, the winding speed is 1100 m / min, the drawing temperature is 67°C, and the two-stage drawing ratio is 3.3 times;

[0283] The spinneret holes in the spinneret used for spinning are in a ratio of 1:1 of king-shaped and cross-shaped.

[0284] The finally prepared flame retardant and melt-dripping resistant polyester fiber has a fineness of 11.11 dtex, a breaking strength of 5.3 cN / dtex, an elongation at break of 27.4%, a crimp number of 11.9 per 25 mm, a crimp ratio of 11.6%, an LOI of 30.9%, and no melt dripping occurs during the combustion process.

[0285] Example 13

[0286] The preparation method of the flame retardant and melt-dripping resistant polyester fiber is basically the same as that of Example 12, except that: the melt-dripping inhibitor used in step (3) is XR.

[0287] The finally prepared flame retardant and melt-dripping resistant polyester fiber has a fineness of 11.12 dtex, a breaking strength of 5.4 cN / dtex, an elongation at break of 27.1%, a crimp number of 10.8 per 25 mm, a crimp ratio of 12%, an LOI of 30.7%, and no melt dripping occurs during the combustion process.

[0288] Example 14

[0289] The preparation method of the flame retardant and melt-dripping resistant polyester fiber is basically the same as that of Example 12, except that: the melt-dripping inhibitor used in step (3) is ETFE.

[0290] The final flame retardant and droplet-suppressed polyester fiber has a fineness of 11.11 dtex, a breaking strength of 5.4 cN / dtex, an elongation at break of 27.6%, a crimp number of 11.1 / 25mm, a crimp rate of 12.7%, an LOI of 30.6%, and no droplets are generated during the combustion process.

[0291] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A method for preparing flame retardant and droplet-suppressing polyester fiber, characterized in that: The polyester, the flame retardant polyester masterbatch and the dripping inhibitor are mixed and then melt-spinned to obtain the flame retardant and dripping inhibitor polyester fiber; The flame retardant polyester masterbatch is flame retardant polyester masterbatch A or flame retardant polyester masterbatch B; The preparation process of the flame retardant polyester masterbatch A is as follows: in the process of preparing polyester, a phosphorus-based flame retardant is added to the system in the esterification stage, and a nitrogen-based flame retardant and a silicon-based flame retardant are added to the system in the polycondensation stage, so as to obtain the flame retardant polyester masterbatch A; The preparation process of the flame retardant polyester masterbatch B is as follows: the polyester and the IFR are melt-blended to obtain the flame retardant polyester masterbatch B; The phosphorus flame retardant is one or more of DDP and CEPPA; The nitrogen flame retardant is one or more of MCA, KH550 and hexagonal boron nitride; The silicon-based flame retardant is one or more of silicate, silicon dioxide and POSS; The dripping inhibitor is one or more of polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-polyvinylidene fluoride copolymer, polyhexafluoropropylene, tetrafluoroethylene-polyhexafluoropropylene copolymer, tetrafluoroethylene-polyvinylidene fluoride-polyhexafluoropropylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, copolymer of tetrafluoroethylene and other copolymerizable olefin unsaturated monomers, sulfobutyl-β-cyclodextrin, and potassium perfluorobutyl sulfonate; The mass ratio of polyester, flame retardant polyester masterbatch and drip inhibitor is 65-75:15-25:2-20; The contents of phosphorus flame retardant, nitrogen flame retardant and silicon flame retardant in the flame retardant polyester masterbatch A are 0.5-1wt%, 1-5wt% and 0.5-1wt% respectively; the content of IFR in the flame retardant polyester masterbatch B is 5-20wt%.

2. The method for preparing flame retardant and drip-suppressing polyester fiber according to claim 1, characterized in that: The mass ratio of polyester, flame retardant polyester masterbatch and drip inhibitor is 75:20:5, or 70:20:10, or 65:20:

15.

3. The method for preparing the flame retardant and droplet-suppressing polyester fiber according to claim 1, characterized in that: The polyester, flame retardant polyester masterbatch and drip inhibitor are all dried before mixing, the drying temperature is 116-120°C, and the moisture content after drying is less than 100ppm.

4. The method for preparing the flame retardant and dripping-suppressing polyester fiber according to claim 1, characterized in that: The preparation steps of flame retardant polyester masterbatch A are as follows: (1) ethylene glycol and terephthalic acid are slurried and mixed, and a phosphorus-based flame retardant is added to the system; (2) Under the protection of nitrogen or inert gas, the system temperature is raised from 150°C to 280°C within 30 minutes, and the temperature is kept for reaction for 1.5 to 2.5 hours; (3) Adding nitrogen-based flame retardant and silicon-based flame retardant into the system, raising the temperature to 295° C., and reacting for 2 to 3 hours under a vacuum degree of less than 50 Pa, thereby obtaining flame-retardant polyester masterbatch A.

5. The method for preparing the flame retardant and droplet-suppressing polyester fiber according to claim 1, characterized in that: The process flow of melt spinning includes: melt extrusion by screw extruder → spinning → cooling by annular air blowing → winding → forming to obtain raw yarn → raw yarn bundling → two-stage drawing → tension heat setting → curling → oiling → relaxation heat setting → cutting.

6. The method for preparing the flame retardant and droplet-suppressing polyester fiber according to claim 5, characterized in that: The process parameters of melt spinning include: temperature of each zone of the screw extruder is 265-290°C, temperature of the spinning box is 275-290°C, supply of the metering pump is 500-900g / min, temperature of the annular air is 25-30°C, inlet pressure of the annular air is 500-800Pa, winding speed is 900-1100m / min, drawing temperature is 65±5°C, and secondary drawing multiple is 3-4 times.

7. The method for preparing the flame retardant and droplet-suppressing polyester fiber according to claim 6, characterized in that: The temperatures of zones 1 to 6 of the screw extruder correspond to 265°C, 275°C, 280°C, 285°C, 280°C, and 275°C, respectively, and the spinning box temperature is 275°C; alternatively, the temperatures of zones 1 to 6 of the screw extruder correspond to 265°C, 270°C, 275°C, 280°C, 275°C, and 270°C, respectively, and the spinning box temperature is 270°C; alternatively, the temperatures of zones 1 to 6 of the screw extruder correspond to 270°C, 275°C, 280°C, 285°C, 280°C, and 275°C, respectively, and the spinning box temperature is 275°C.

8. The method for preparing the flame retardant and droplet-suppressing polyester fiber according to claim 5, characterized in that: The spinneret holes in the spinneret used for spinning are one or more of the following shapes: a W-shaped, a cross-shaped, a trilobal-shaped, and a quad-T-shaped.

9. The method for preparing the flame retardant and dripping-suppressing polyester fiber according to any one of claims 1 to 8, characterized in that: The flame retardant and droplet-suppressing polyester fiber has a fineness of 0.89-22.22 dtex, a breaking strength of 5.3-6.0 cN / dtex, a breaking elongation of 27.1-30.7%, a crimp number of 10.4-11.9 / 25mm, a crimp rate of 11.1-12.7%, an LOI of more than 30%, and no droplets are generated during the combustion process.

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