Flame-retardant modified polyester fiber and preparation method thereof

Abstract

The application provides a flame-retardant modified polyester fiber and a preparation method thereof, and the in-situ polymerization polyester fiber of the application utilizes the flame-retardant superposition of antimony ene nanosheets and flame-retardant additives, the modification and compounding of triethylamine and polyphosphate, is helpful to capture hydroxyl radicals, and improves the overall flame-retardant performance of the fiber when being burned; for the flame-retardant polyester fiber, the organic phosphorus compound has good flame-retardant performance as the flame-retardant additive, and in addition, the modification treatment agent system is beneficial to improving the compatibility between the polyester particles and the flame-retardant additives, thereby improving the stability strength and flame-retardant effect stability of the finished product; the combination twisting mode of the in-situ polymerization polyester fiber and the flame-retardant polyester fiber strengthens the mechanical properties of the overall fiber, and in the process of being subjected to external combustion and melting, the two have good compatibility stability, which is beneficial to the superposition of the flame-retardant performance.

Description

Technical Field

[0001] This invention relates to the field of textile fiber preparation technology, specifically to a flame-retardant modified polyester fiber and its preparation method. Background Technology

[0002] Polyester fiber is an important type of synthetic fiber and is the commercial name for polyester fiber in my country. It is a fiber-forming polymer—polyethylene terephthalate—obtained from purified terephthalic acid or dimethyl terephthalate and ethylene glycol through esterification or transesterification and polycondensation reactions, and then spun and post-processed into fiber. Polyester fiber is the simplest to manufacture among the three major synthetic fibers and is relatively inexpensive. Furthermore, it is popular due to its durability, elasticity, resistance to deformation, corrosion resistance, insulation, crispness, and quick-drying properties. Polyester fiber fabrics are diverse, including pure polyester fabrics and many blends or interweaves with various textile fibers, compensating for the shortcomings of pure polyester fabrics and enhancing their performance.

[0003] With sustained and rapid economic growth and the continuous improvement of residents' consumption capacity, society has put forward new functional requirements for polyester fibers. For applications of polyester in fire-fighting clothing and decorative fabrics such as curtains and sofa fabrics, excellent flame-retardant properties are required. Therefore, to ensure the flame-retardant performance of polyester fabrics, we have conducted further research and improvement on the flame-retardant properties of polyester fibers. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings and deficiencies of the prior art by providing a flame-retardant modified polyester fiber and its preparation method.

[0005] To achieve the above objectives, the present invention proposes the following technical solution:

[0006] A flame-retardant modified polyester fiber, comprising in-situ polymerized polyester fiber and flame-retardant polyester fiber:

[0007] The flame-retardant polyester fiber content is 60-80%, and the remainder is in-situ polymerized polyester fiber;

[0008] Using the unit cross-sectional area of ​​flame-retardant polyester fiber as a unit, the flame-retardant polyester fiber comprises the following parts by weight of raw materials:

[0009] 100 parts of polyethylene terephthalate;

[0010] 35-50 parts of flame-retardant filler;

[0011] 30-50 parts of the modifier;

[0012] Taking the unit cross-sectional area of ​​the in-situ polymerized polyester fiber as a unit, the in-situ polymerized polyester fiber comprises the following parts by weight of raw materials:

[0013]

[0014] Based on the above scheme and as a preferred embodiment of the above scheme, the flame-retardant filler is an organophosphorus compound.

[0015] Based on the above scheme and as a preferred embodiment of the above scheme, the organophosphorus compound is 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphacyclohexane]2,2' disulfide.

[0016] Based on the above scheme and as a preferred embodiment of the above scheme, the modifying agent for the flame-retardant polyester fiber includes 10-15 parts of polyvinyl alcohol, 10-20 parts of graphene oxide, 5-6 parts of zinc borate hydrate, 1-2 parts of ricinoleic acid, and 4-7 parts of triethylamine.

[0017] Based on the above scheme and as a preferred embodiment of the above scheme, the flame retardant additive of the in-situ polymerized polyester fiber is flame retardant modified DOPO, which is modified by epichlorohydrin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative.

[0018] Based on the above scheme and as a preferred embodiment of the above scheme, the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative is 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, and the molar ratio of the derivative to epichlorohydrin is 1:1.

[0019] Based on the above scheme and as a preferred embodiment of the above scheme, a method for preparing flame-retardant modified polyester fiber is provided, wherein the in-situ polymerized polyester fiber is twisted along the S direction of the flame-retardant polyester fiber.

[0020] Based on the above scheme and as a preferred embodiment of the above scheme, the in-situ polymerized polyester fiber preparation method includes the following steps:

[0021] S1, Preparation of in-situ polymerized polyester chips

[0022] Weighed PTA and ethylene glycol were simultaneously added to a polymerization reactor and stirred for 0.5-1 h. Then, under nitrogen protection at 0.3 MPa, flame retardant additives, triethylamine, polyphosphate, and antimony nanosheets were added and stirred thoroughly. The pressure of the polymerization reactor was adjusted to 0.40±0.50 MPa, and the temperature was maintained at 230-240℃ for 4.5-7.5 h. The pressure was stopped, and esterification was carried out at atmospheric pressure for 30 min. Then, the temperature was raised to 280-285℃ and maintained for 30 min. A high vacuum was applied to make the vacuum degree less than 50 Pa. When the polycondensation current reached 0.6 A, the reaction ended, and in-situ polymerized polyester chips were obtained.

[0023] S2, Preparation of in-situ polymerized polyester fibers

[0024] The in-situ polymerized polyester chips described in step 1) were melt-spun, with the following temperatures for each zone of the spinning machine screw: Zone I 285℃, Zone II 280℃, Zone III 265℃, and Zone IV 270℃; and in-situ polymerized polyester fibers were prepared at a spinning speed of 650 m / min.

[0025] Based on the above scheme and as a preferred embodiment of the above scheme, the method for preparing the flame-retardant polyester fiber includes the following steps:

[0026] 1) Prepare a 1-15 mg / mL aqueous solution of graphene oxide. Then, add 10-15 parts of polyvinyl alcohol (polyvinyl alcohol) relative to the mass of polyethylene terephthalate to 50 parts of the aqueous solution of graphene oxide. Place the solution in a constant temperature water bath at 65°C and stir for 30 min. Then remove the constant temperature water bath at 65°C and stir until room temperature to obtain mixed solution A.

[0027] 2) Mix zinc borate hydrate and ricinoleic acid, and keep warm and stir at 60-70℃ for 1-2 hours to obtain mixed solution B; then mix mixed solution A and mixed solution B by ultrasonication for 5-15 minutes to obtain a homogeneous mixed solution.

[0028] 3) Take triethylamine and add it to the uniformly mixed solution in step 2). Stir it evenly under a constant temperature water bath at 65°C. Then add polyethylene terephthalate and stir for 1-2 hours. Filter and dry at room temperature to obtain the modified polyethylene terephthalate matrix.

[0029] 4) The modified polyethylene terephthalate matrix described in step 3) is mixed with flame retardant filler, heated to melt, extruded, and spun into flame retardant polyester fibers.

[0030] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0031] This invention discloses a flame-retardant modified polyester fiber and its preparation method. The in-situ polymerized polyester fiber of this invention utilizes the combined flame-retardant properties of antimony nanosheets and flame-retardant additives, along with the modified compounding of triethylamine and polyphosphate, which helps to capture hydroxyl radicals and improve the overall flame-retardant performance of the fiber when burned. For the flame-retardant polyester fiber, organophosphorus compounds, as flame-retardant additives, have good flame-retardant properties. In addition, the modification treatment system helps to improve the compatibility between polyester particles and flame-retardant additives, thereby improving the stability and flame-retardant effect stability of the finished product. The combined twisting method of the in-situ polymerized polyester fiber and the flame-retardant polyester fiber strengthens the overall mechanical properties of the fiber. Moreover, during the external combustion and melting process, the similarity and proximity of the two, utilizing triethylamine, oleic acid, and flame-retardant modified DOPO system, helps to improve compatibility stability and thus isolate oxygen, which is beneficial to further enhance the flame-retardant performance.

[0032] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the subject matter disclosure of the present invention, provided that such concepts do not contradict each other.

[0033] The foregoing and other aspects, embodiments, and features of the teachings of this invention will be more fully understood from the following description. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of this invention. Attached Figure Description

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0035] Figure 1 This is a schematic diagram of the reaction principle of flame-retardant modified DOPO. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0037] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" mean that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0038] Polyester fiber is a synthetic fiber obtained by spinning polyester, a polymer formed by the condensation polymerization of organic diacids and diols. Invented in 1941, it is currently the largest variety of synthetic fiber due to its numerous advantages, such as excellent wrinkle resistance and shape retention, high strength and elastic recovery, durability, wrinkle resistance, and non-lint properties. It has become the fastest-growing and highest-producing synthetic fiber, widely used in clothing, bedding, various decorative fabrics, special textiles for national defense and military industries, and other industrial fiber products. With societal progress and increasing public awareness of safety, special industries such as fire protection, power, and metallurgy have increasingly higher requirements for protective clothing, seeking to further improve its performance, stability, and durability. This necessitates fabrics with good flame-retardant properties. Existing flame-retardant processes often involve laminating or coating two fabrics, resulting in thick, non-breathable fabrics with high production costs and energy consumption. Furthermore, coated fabrics do not exhibit the same flame-retardant stability as those made from fibers with inherent flame-retardant properties. Therefore, we are dedicated to researching the inherent flame-retardant properties of the fiber itself. Flame retardant additives are an important component of this process.

[0039] The application fields of polyester fiber materials are constantly expanding. Most synthetic fiber materials have low LOI (Lowest Intake) and high calorific value, and their performance largely depends on the performance of flame retardants. To date, halogenated flame retardants offer the best performance-to-price ratio. However, their application is limited due to inherent performance issues. Some countries have already refused to import flame-retardant products containing decabromodiphenyl ether (DBDPO), placing pressure on flame-retardant materials in terms of price, recycling, environmental protection, processing technology, and performance. With increasingly stringent fire safety standards and environmental requirements, halogen-free, low-smoke, and non-toxic environmentally friendly flame retardants have become a research hotspot. Therefore, we have conducted numerous trials and explorations in the selection of flame retardants.

[0040] In this invention, the flame-retardant additive for the in-situ polymerized polyester fiber is flame-retardant modified DOPO, which is prepared by modifying a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative with epichlorohydrin. The specific principle utilizes the characteristic of DOPO having a six-membered phosphorus heterocyclic structure, where phosphorus (P) has a lone pair of electrons, leading to nucleophilic addition. Therefore, DOPO can react with benzoquinone and other compounds to obtain dihydroxy compounds, thus yielding the 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide of this invention. The reaction principle and preparation method are clear and will not be elaborated here. The modification and preparation method of 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide is as follows:

[0041] Weigh out 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide and epichlorohydrin in a molar ratio of 1:5 and add them to a four-necked flask. Simultaneously add benzyltriethylammonium chloride (molar ratio of 5:1 relative to 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide). Stir at 90°C for 2 hours and then cool to room temperature. Add a small amount of benzyltriethylammonium chloride and 5M NaOH aqueous solution (the amount of NaOH used is 1:2 relative to the amount of 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide). Stir the mixture at room temperature for 30 minutes. Finally, rinse with brine and dry with anhydrous Na2SO4. Evaporate excess epichlorohydrin using a rotary evaporator. Finally, further purification yields the product, namely the flame-retardant modified DOPO of this invention, the reaction principle of which is as follows: Figure 1 As shown.

[0042] In the preparation of in-situ polymerized polyester fibers, flame-retardant modified DOPO is chosen as the flame-retardant additive for the following reasons: First, epichlorohydrin can shield the terminal hydroxyl groups in 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, reducing the impact of the weak acidity of the terminal hydroxyl groups on the in-situ polymerization system; second, regarding the other terminal hydroxyl group, due to its presence, the system still contains a weak acidity. The reaction of triethylamine in the system with the weak acid improves the additive's performance. The compatibility and dispersibility between the agent and the matrix raw materials are improved, thereby enhancing the overall strength and flame retardant effect of the in-situ polymerized polyester fiber; thirdly, regarding polyphosphate and ethylene glycol, since ethylene glycol is in excess in this invention (the general molar ratio of PTA to ethylene glycol is 1:2, the molecular weight of PTA is 166, and the molecular weight of ethylene glycol is 62), the multi-component compounding of polyphosphate, ethylene glycol, and triethylamine, after complete fusion, helps to capture hydroxyl radicals and oxygen radicals, thereby improving the flame retardant performance of the fiber when burned.

[0043] Furthermore, the antimonyene nanosheets used in the in-situ polymerized polyester fibers were purchased from Xi'an Qiyue Biotechnology Co., Ltd. Antimonyene nanosheets break away from the conventional antimony-containing raw material model used in traditional flame retardant materials, solving the problems of the instability of ordinary antimony in air, its inability to be used alone, and the cost-effectiveness of antimony oxides. Antimonyene nanosheets are nano-two-dimensional structures prepared from elemental antimony through processing. They exhibit stability in air at room temperature and pressure and also possess a larger specific surface area. Adding antimony nanomaterials to polyester materials results in a bidirectional modification effect, ultimately achieving flame-retardant modification of the fiber material. In the in-situ polymerization process of PTA and ethylene glycol, which involves esterification and polycondensation, the addition of antimonyene nanosheets under nitrogen protection better leverages its two-dimensional material advantages, promoting compatibility and expansion between materials, facilitating the dispersion and flame-retardant effect of flame retardant additives in the system, and thus enhancing the flame-retardant effect of the chips.

[0044] Example 1

[0045] A flame-retardant modified polyester fiber includes in-situ polymerized polyester fiber and flame-retardant polyester fiber; the flame-retardant polyester fiber accounts for 60% of the total content, and the remainder is in-situ polymerized polyester fiber; and the in-situ polymerized polyester fiber is twisted along the S-direction of the flame-retardant polyester fiber.

[0046] Furthermore, taking the unit cross-sectional area of ​​the flame-retardant polyester fiber as a unit, the flame-retardant polyester fiber comprises the following raw materials in parts by weight: 100 parts of polyethylene terephthalate, 35 parts of 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphacyclohexane]2,2' disulfide; and 30 parts of a modifying agent.

[0047] Furthermore, the modifying agent comprises 10 parts polyvinyl alcohol, 10 parts graphene oxide, 5 parts zinc borate hydrate, 1 part ricinoleic acid, and 4 parts triethylamine.

[0048] The method for preparing the flame-retardant polyester fiber includes the following steps:

[0049] 1) Prepare a 6 mg / mL aqueous solution of graphene oxide. Then, add 10 parts polyvinyl alcohol (PVA) relative to the mass of polyethylene terephthalate (PET) to 50 parts of the aqueous solution of graphene oxide. PVA acts as a substrate modifier and can form intermolecular forces with graphene oxide, which can improve the stability of the substrate. Place the solution in a 65°C constant temperature water bath and stir for 30 min. Then remove the 65°C constant temperature water bath and stir until room temperature to obtain mixed solution A.

[0050] 2) Mix zinc borate hydrate and ricinoleic acid, and keep warm and stir at 60-70℃ for 1-2 hours to obtain mixed solution B; then mix mixed solution A and mixed solution B by ultrasonication for 15 minutes to obtain a homogeneous mixed solution.

[0051] 3) Take triethylamine and add it to the uniformly mixed solution in step 2). Stir it evenly under a constant temperature water bath at 65°C. Then add polyethylene terephthalate and stir for 1-2 hours. Filter and dry at room temperature to obtain the modified polyethylene terephthalate matrix.

[0052] 4) The modified polyethylene terephthalate matrix described in step 3) is mixed with flame retardant filler, heated to melt, extruded, and spun into flame retardant polyester fibers.

[0053] In the flame-retardant modified polyester fiber of the present invention, the unit cross-sectional area of ​​the in-situ polymerized polyester fiber is taken as one part, and the in-situ polymerized polyester fiber comprises the following parts by weight of raw materials:

[0054] 100 parts PTA, 80 parts ethylene glycol, 10 parts flame-retardant modified DOPO, 3 parts triethylamine, 1 part polyphosphate, and 15 parts antimony nanosheets.

[0055] Furthermore, the flame-retardant modified DOPO is prepared by epichlorohydrin and 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide in a molar ratio of 1:1. Furthermore, the 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide is a derivative of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0056] Specifically, the in-situ polymerized polyester fiber preparation method includes the following steps:

[0057] S1, Preparation of in-situ polymerized polyester chips

[0058] Weighed PTA and ethylene glycol were simultaneously added to a polymerization reactor and stirred for 0.5 h. Then, under nitrogen protection at 0.3 MPa, flame-retardant modified DOPO, triethylamine, polyphosphate, and antimony nanosheets were added and stirred thoroughly. The pressure of the polymerization reactor was adjusted to 0.40 ± 0.50 MPa, and the reactor was kept at 230℃ for 4.5 h. The pressure was then stopped, and esterification was carried out at atmospheric pressure for 30 min. The temperature was then raised to 280℃ and held for 30 min. A high vacuum was applied to reduce the vacuum level to less than 50 Pa. When the polycondensation current reached 0.6 A, the reaction ended, and in-situ polymerized polyester chips were obtained.

[0059] S2, Preparation of in-situ polymerized polyester fibers

[0060] The in-situ polymerized polyester chips described in step 1) were melt-spun, with the following temperatures for each zone of the spinning machine screw: Zone I 285℃, Zone II 280℃, Zone III 265℃, and Zone IV 270℃; and in-situ polymerized polyester fibers were prepared at a spinning speed of 650 m / min.

[0061] Example 2

[0062] Unlike Example 1 above, the flame-retardant polyester fiber is defined as a unit cross-sectional area, and the flame-retardant polyester fiber comprises the following raw materials in parts by weight: 100 parts of polyethylene terephthalate, 50 parts of 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphacyclohexane]2,2' disulfide; and 50 parts of a modifying agent.

[0063] Furthermore, the modifying agent comprises 15 parts polyvinyl alcohol, 20 parts graphene oxide, 6 parts zinc borate hydrate, 2 parts ricinoleic acid, and 7 parts triethylamine.

[0064] The method for preparing the flame-retardant polyester fiber includes the following steps:

[0065] 1) Prepare a 6 mg / mL aqueous solution of graphene oxide. Then, add 10 parts of polyvinyl alcohol relative to the mass of polyethylene terephthalate to 50 parts of the aqueous solution of graphene oxide. Place the solution in a constant temperature water bath at 65°C and stir for 30 min. Then remove the constant temperature water bath at 65°C and stir until room temperature to obtain mixed solution A.

[0066] 2) Mix zinc borate hydrate and ricinoleic acid, and keep warm and stir at 60-70℃ for 1-2 hours to obtain mixed solution B; then mix mixed solution A and mixed solution B by ultrasonication for 15 minutes to obtain a homogeneous mixed solution.

[0067] 3) Take triethylamine and add it to the uniformly mixed solution in step 2). Stir it evenly under a constant temperature water bath at 65°C. Then add polyethylene terephthalate and stir for 1-2 hours. Filter and dry at room temperature to obtain the modified polyethylene terephthalate matrix.

[0068] 4) The modified polyethylene terephthalate matrix described in step 3) is mixed with flame retardant filler, heated to melt, extruded, and spun into flame retardant polyester fibers.

[0069] In the flame-retardant modified polyester fiber of the present invention, the in-situ polymerized polyester fiber is prepared by the same method as in Example 1.

[0070] Example 3

[0071] Unlike Example 2 above, the in-situ polymerized polyester fiber is defined as a unit cross-sectional area, and the in-situ polymerized polyester fiber comprises the following parts by weight of raw materials:

[0072] 100 parts PTA, 80 parts ethylene glycol, 25 parts flame-retardant modified DOPO, 15 parts triethylamine, 10 parts polyphosphate, and 50 parts antimony nanosheets.

[0073] Furthermore, the flame-retardant modified DOPO is prepared by epichlorohydrin and 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide in a molar ratio of 1:1. Furthermore, the 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide is a derivative of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0074] Specifically, the in-situ polymerized polyester fiber preparation method includes the following steps:

[0075] S1, Preparation of in-situ polymerized polyester chips

[0076] Weighed PTA and ethylene glycol were simultaneously added to a polymerization reactor and stirred for 1 hour. Then, under nitrogen protection at 0.3 MPa, flame-retardant modified DOPO, triethylamine, polyphosphate, and antimony nanosheets were added and stirred thoroughly. The pressure of the polymerization reactor was adjusted to 0.40 ± 0.50 MPa, and the reactor was kept at 240°C for 7.5 hours. The pressure was then stopped, and esterification was carried out at atmospheric pressure for 30 minutes. The temperature was then raised to 285°C and held for 30 minutes. A high vacuum was applied to reduce the vacuum level to less than 50 Pa. When the polycondensation current reached 0.6 A, the reaction ended, and in-situ polymerized polyester chips were obtained.

[0077] S2, Preparation of in-situ polymerized polyester fibers

[0078] The in-situ polymerized polyester chips described in step 1) were melt-spun, with the following temperatures for each zone of the spinning machine screw: Zone I 285℃, Zone II 280℃, Zone III 265℃, and Zone IV 270℃; and in-situ polymerized polyester fibers were prepared at a spinning speed of 650 m / min.

[0079] Example 4

[0080] Unlike Example 1 above, a flame-retardant modified polyester fiber includes in-situ polymerized polyester fiber and flame-retardant polyester fiber; the flame-retardant polyester fiber accounts for 80% of the total content, and the remainder is in-situ polymerized polyester fiber; and the in-situ polymerized polyester fiber is twisted along the S-direction of the flame-retardant polyester fiber. The remaining steps are the same as in Example 1.

[0081] Comparative Example 1

[0082] Unlike Example 1, a unit cross-sectional area of ​​the in-situ polymerized polyester fiber is considered as one unit, and the in-situ polymerized polyester fiber comprises the following parts of raw material:

[0083] 100 parts PTA, 80 parts ethylene glycol, 10 parts flame-retardant modified DOPO, 3 parts triethylamine, and 1 part polyphosphate.

[0084] Comparative Example 2

[0085] Unlike Example 1, the in-situ polymerized polyester fiber comprises the following parts of raw materials:

[0086] 100 parts PTA, 80 parts ethylene glycol, 10 parts flame-retardant modified DOPO, 3 parts triethylamine, and 15 parts antimony nanosheets.

[0087] Comparative Example 3

[0088] Unlike Example 1, the in-situ polymerized polyester fiber comprises the following raw materials in parts by weight:

[0089] 100 parts PTA, 80 parts ethylene glycol, 1 part polyphosphate, and 15 parts antimony nanosheets.

[0090] Comparative Example 4

[0091] Unlike Example 1, the flame-retardant polyester fiber comprises the following raw materials in parts by weight:

[0092] 100 parts polyethylene terephthalate, 30 parts modifier.

[0093] Furthermore, the modifying agent comprises 10 parts polyvinyl alcohol, 10 parts graphene oxide, 5 parts zinc borate hydrate, 1 part ricinoleic acid, and 4 parts triethylamine.

[0094] Comparative Example 5

[0095] Unlike Example 1, the flame-retardant polyester fiber comprises the following raw materials in parts by weight: 100 parts of polyethylene terephthalate, 35 parts of 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphacyclohexane]2,2' disulfide, and 20 parts of a modifying agent.

[0096] Furthermore, the modifying agent comprises 10 parts polyvinyl alcohol, 5 parts zinc borate hydrate, 1 part ricinoleic acid, and 4 parts triethylamine.

[0097] Comparative Example 6

[0098] Unlike Example 1, the flame-retardant polyester fiber comprises the following raw materials in parts by weight: 100 parts of polyethylene terephthalate, 35 parts of 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphacyclohexane]2,2' disulfide, and 20 parts of a modifying agent.

[0099] Furthermore, the modifying agent includes 10 parts of polyvinyl alcohol and 10 parts of graphene oxide.

[0100] Comparative Example 7

[0101] Unlike Example 1, a flame-retardant modified polyester fiber includes 100% in-situ polymerized polyester fiber, and the preparation method of the in-situ polymerized polyester fiber is the same as that in Example 1.

[0102] Comparative Example 8

[0103] Unlike Example 1, a flame-retardant modified polyester fiber is provided, comprising 100% flame-retardant polyester fiber, and the preparation method of the flame-retardant polyester fiber is the same as in Example 1.

[0104] Performance testing

[0105] The fibers from Examples 1-4 and Comparative Examples 1-8 were subjected to performance tests to further compare the effects of the addition of relevant materials on the overall fiber properties. The relevant tests and reference testing standards are as follows:

[0106] Fiber mechanical strength test: The mechanical properties of the fiber were tested using an XL-1 multifilament tensile strength tester.

[0107] Flame retardant performance test: The oxygen index of the sample was tested using a JF-3 oxygen index meter in accordance with the GB / T 8924-2005 standard.

[0108] Vertical burning performance: The UL-94 vertical burning performance of the test specimens was tested according to GB / T 8924—2008 standard.

[0109] The relevant test results are shown in the table below:

[0110] Table 1 Comparison of Fiber Performance Test Results

[0111]

[0112] The comparative analysis of the above results shows that 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphacyclohexane]2,2' disulfide of flame-retardant polyester fiber, as an organophosphorus flame retardant, has good flame-retardant properties. Furthermore, the use of polyvinyl alcohol and graphene oxide as a stable substrate is beneficial for the stabilizing effect of the modification agent system: polyvinyl alcohol, as the substrate of the modification agent, can form intermolecular forces with graphene oxide, which can improve the stability of the substrate and help improve the dispersibility and stability of the organophosphorus flame retardant; the addition of triethylamine, blended with zinc borate treated with castor oil acid, can effectively improve the compatibility of the raw materials through the reaction of amine and oleic acid, thereby improving the stability and strength of the finished product.

[0113] Flame-retardant polyester fibers and in-situ polymerized polyester fibers can not only exert their own flame-retardant effects, but also improve compatibility stability by utilizing the similarity and proximity of triethylamine, oleic acid, and flame-retardant modified DOPO system. During the external combustion and melting process, they can isolate oxygen, which is conducive to further enhancing flame-retardant performance.

[0114] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A flame-retardant modified polyester fiber, characterized in that, Including in-situ polymerized polyester fibers and flame-retardant polyester fibers: The flame-retardant polyester fiber content is 60-80%, and the remainder is in-situ polymerized polyester fiber; Using the unit cross-sectional area of ​​flame-retardant polyester fiber as a unit, the flame-retardant polyester fiber comprises the following parts by weight of raw materials: 100 parts of polyethylene terephthalate; 35-50 parts of flame-retardant filler; 30-50 parts of the modifier; The flame-retardant filler is an organophosphorus compound, and the organophosphorus compound is 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphanecyclohexane]2,2' disulfide; Taking the unit cross-sectional area of ​​the in-situ polymerized polyester fiber as a unit, the in-situ polymerized polyester fiber comprises the following parts of raw material: 100 servings of PTA; 80 parts of ethylene glycol; 10-25 parts flame retardant additive; 3-15 parts of triethylamine; 1-10 parts of polyphosphate; 15-50 parts of antimonene nanosheets; The flame retardant additive is flame retardant modified DOPO, which is modified by epichlorohydrin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives. The modifying agent for the flame-retardant polyester fiber includes 10-15 parts of polyvinyl alcohol, 10-20 parts of graphene oxide, 5-6 parts of zinc borate hydrate, 1-2 parts of ricinoleic acid, and 4-7 parts of triethylamine.

2. The flame-retardant modified polyester fiber according to claim 1, characterized in that, The 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative is 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, and the molar ratio of it to epichlorohydrin is 1:

1.

3. A method for preparing the flame-retardant modified polyester fiber as described in claim 1, characterized in that, The in-situ polymerized polyester fiber is twisted along the S-direction of the flame-retardant polyester fiber.

4. A method for preparing a flame-retardant modified polyester fiber as described in claim 3, characterized in that, The in-situ polymerized polyester fiber preparation method includes the following steps: S1, Preparation of in-situ polymerized polyester chips Weighed PTA and ethylene glycol were simultaneously added to a polymerization reactor and stirred for 0.5-1 h. Then, under nitrogen protection at 0.3 MPa, flame retardant additives, triethylamine, polyphosphate, and antimony nanosheets were added and stirred thoroughly. The pressure of the polymerization reactor was adjusted to 0.40±0.50 MPa, and the temperature was maintained at 230-240℃ for 4.5-7.5 h. The pressure was stopped, and esterification was carried out at atmospheric pressure for 30 min. Then, the temperature was raised to 280-285℃ and maintained for 30 min. A high vacuum was applied to make the vacuum degree less than 50 Pa. When the polycondensation current reached 0.6 A, the reaction ended, and in-situ polymerized polyester chips were obtained. S2, Preparation of in-situ polymerized polyester fibers The in-situ polymerized polyester chips obtained in step 1) were melt-spun, and the temperatures of each zone of the spinning machine screw were: zone I 285℃, zone II 280℃, zone III 265℃, and zone IV 270℃; and in-situ polymerized polyester fibers were prepared at a spinning speed of 650 m / min.

5. A method for preparing a flame-retardant modified polyester fiber as described in claim 3, characterized in that, The method for preparing the flame-retardant polyester fiber includes the following steps: 1) Prepare a 1-15 mg / mL aqueous solution of graphene oxide. Then, add 10-15 parts of polyvinyl alcohol (polyvinyl alcohol) relative to the mass of polyethylene terephthalate to 50 parts of the aqueous solution of graphene oxide. Place the solution in a constant temperature water bath at 65°C and stir for 30 min. Then remove the constant temperature water bath at 65°C and stir until room temperature to obtain mixed solution A. 2) Mix zinc borate hydrate and ricinoleic acid, and keep warm and stir at 60-70℃ for 1-2 hours to obtain mixed solution B; then mix mixed solution A and mixed solution B by ultrasonication for 5-15 minutes to obtain a homogeneous mixed solution. 3) Take triethylamine and add it to the uniformly mixed solution in step 2). Stir it evenly under a constant temperature water bath at 65°C. Then add polyethylene terephthalate and stir for 1-2 hours. Filter and dry at room temperature to obtain the modified polyethylene terephthalate matrix. 4) The modified polyethylene terephthalate matrix described in step 3) is mixed with flame retardant filler, heated to melt, extruded, and spun into flame retardant polyester fibers.

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