PBO composite fiber and preparation method thereof

Abstract

The invention discloses a PBO composite fiber and a preparation method thereof, the PBO composite fiber comprises a PBO fiber, a para-aramid fiber and a flame-retardant viscose fiber, and the weight content of the PBO fiber is at least 20%. On the basis of keeping ultrahigh strength and high modulus of the PBO fiber, the wear resistance, light resistance and compression performance are remarkably improved, permanent and more balanced flame retardant performance is given, and meanwhile the cost is effectively reduced.

Description

Technical Field

[0001] This invention relates to a high-strength, high-modulus flame-retardant fiber, belonging to the field of high-performance materials technology, and particularly to a PBO composite fiber and its preparation method. Background Technology

[0002] Poly(p-phenylenebenzodioxazole) (PBO) fiber is a polyamide containing heterocyclic aromatics. It is one of the strongest and highest modulus organic fibers currently available in the market, with a strength of up to 5.8 GPa, a modulus of up to 270 GPa, a limiting oxygen index (LOI) of up to 68%, and a heat resistance temperature of up to 600℃. It has excellent flame retardancy and thermal stability, does not burn or shrink in flames, and is known as the super fiber of the 21st century. It has important application value in aerospace, military defense, transportation, sports equipment, building materials, high-temperature protection and other fields.

[0003] However, PBO fibers also have some significant drawbacks: First, they are extremely expensive, which limits their large-scale application; second, they have poor abrasion resistance and light resistance, and their performance will degrade under repeated friction or long-term ultraviolet radiation; third, their compression and shear resistance are relatively weak. In particular, PBO has poor spinning / spinning performance (spinnability), and poor spinnability will also lead to problems such as poor abrasion resistance, poor tear strength, and high mechanical wear, thereby reducing the performance of PBO.

[0004] Currently, single fibers are insufficient to meet the increasingly stringent requirements for comprehensive material performance in the field of special protection. For example, CN101649553B utilizes PBO fibers modified with terminal carboxyl-containing liquid rubber to prepare a composite material, increasing the shear strength of PBO fibers to 26-29 MPa.

[0005] There are also some attempts to blend high-performance fibers. For example, CN105113073B involves unwinding and twisting quartz fiber and PBO fiber filaments in a certain proportion, then twisting a certain number of strands of the blended initial twist yarn together to produce quartz fiber blended yarn, combining the advantages of both fibers. CN113375504A involves uniformly blending ultra-high molecular weight polyethylene fiber, aramid, carbon fiber, PBO fiber, and a small amount of polybutylene terephthalate fiber filaments to improve overall structural performance and reduce density. CN104862826A uses a small amount of PIPD and PBO to prepare blended fibers, improving the wetting properties of PBO and its adhesion to the resin matrix. EP0790339B1 uses stainless steel fiber and PBO fiber to prepare high-temperature resistant blended yarn. JP5257379B2 uses rock wool and PBO to make multi-layer woven fabric, which is then impregnated with phenolic resin.

[0006] Currently, there are also technologies for blending aramid fibers with PBO. For example, JP2008-517181A describes the preparation of flame-retardant fibers by blending para-aramid fibers, meta-aramid fibers, and PBO fibers. However, how to effectively compensate for the shortcomings of PBO fibers, reduce overall costs, and achieve synergistic effects on the performance of each component fiber through scientific formulation design and process innovation, thereby obtaining a composite fiber with optimal overall performance, remains a technical challenge that needs to be solved in this field. Summary of the Invention

[0007] This invention provides a PBO composite fiber and its preparation method, which significantly improves abrasion resistance, light resistance and compression performance while maintaining the ultra-high strength and high modulus of PBO fiber, and endows it with permanent and more balanced flame retardant properties, while effectively reducing costs.

[0008] The first aspect of the present invention is to provide a PBO composite fiber comprising PBO fiber, para-aramid fiber, flame-retardant viscose fiber, and wherein the weight content of PBO fiber is at least 20%.

[0009] In a preferred embodiment, the monofilament strength of the PBO fiber is ≥5.0 GPa, more preferably ≥5.5 GPa, and even more preferably ≥6 GPa.

[0010] In a preferred embodiment, the monofilament modulus of the PBO fiber is ≥180GPa, more preferably ≥190GPa, and even more preferably ≥120GPa.

[0011] In a preferred embodiment, the PBO fiber weight content in the PBO composite fiber is preferably 20-80%, more preferably 20-70%, more preferably 20-60%, and even more preferably 30-60%, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, and 80%.

[0012] In a preferred embodiment, the para-aramid fiber is a para-full aromatic polyamide fiber, such as poly(p-phenylene terephthalamide).

[0013] In a preferred embodiment, the para-aramid fiber weight content in the PBO composite fiber is preferably 15-55%, more preferably 20-50%, more preferably 20-45%, and even more preferably 25-40%, such as 20%, 25%, 30%, 35%, 40%, 45%, and 50%.

[0014] In a preferred embodiment, the flame-retardant viscose fiber is a permanent flame-retardant viscose fiber containing phosphorus-based or silicon-based flame retardants, for example, a permanent flame-retardant viscose fiber modified with phosphorus-based or silicon-based flame retardants.

[0015] In a preferred embodiment, the flame-retardant viscose fiber content in the PBO composite fiber is preferably 5-35% by weight, more preferably 10-30%, such as 10%, 15%, 20%, 25%, or 30%.

[0016] In a preferred embodiment, the PBO composite fiber contains at least two of the various fibers blended together, and preferably all of the fibers blended together.

[0017] In a preferred embodiment, the PBO composite fiber may further include a penetrant (also called an impregnating agent), which is selected from surfactants, especially nonionic surfactants, such as one or more of fatty alcohol polyoxyethylene ethers and alkylphenol polyoxyethylene ethers. Examples of penetrants include one or more of JFC, AEO, FFA, OASE, PT, NP-10, TX-10, OP-10, OPE-10, OPE-70, OPE-98, and OE-35.

[0018] In a preferred embodiment, the PBO composite fiber may further include an antistatic agent, which may be one or more of cationic, anionic, and nonionic antistatic agents. For example, it may be one or more of alkyl sulfonic acid, alkyl phosphoric acid, dithiocarbamate, alkyl quaternary ammonium salt, alkyl phosphonium salt, alkoxylated aliphatic alkylamine or alkoxylated aliphatic alkylamide, and aliphatic carboxylic acid ester. For instance, the antistatic agent may be one or more of 129, 163, KJD-1, KJD-2, KJD-5, KJD-300, KJD-516, KJD-517, KJD-518, KJD-600, KJD-730, KJD-1210, SAS93, SN, TS-1009, T-7, and Atmer163.

[0019] In a preferred embodiment, the PBO composite fiber may further include a lubricant, which may be one or more of the following: mineral lubricant, vegetable lubricant, animal lubricant, and synthetic lubricant. Examples include machine oil, castor oil, tallow, silicone oil, fatty acid amide, oleic acid, polyester nonionic surfactant, polyether nonionic surfactant, paraffin wax, and beeswax.

[0020] In a preferred embodiment, the PBO composite fiber may further include a coupling agent oil (or coupling agent), which may be one or more combinations of silane coupling agents, phosphate coupling agents, chromium complex coupling agents, titanate coupling agents, zirconium coupling agents, and aluminate coupling agents. For example, it may be selected from: γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimeth(eth)oxysilane, silane coupling agent DL602, silane coupling agent DL171, vinyltriethoxysilane, n-octyltriethoxysilane, vinyltriethoxysilane, etc. Methoxysilane, vinyl-tris(2-methoxyethoxy)silane, isopropyl triisostearate titanate, titanate GR-101, isopropyl dioleoyloxy (dioctyl phosphoyloxy) titanate, isopropyl trioleoyloxy titanate, isopropyloxy tris(dodecylbenzenesulfonyloxy) titanate, bis(dioctyloxypyrophosphate) ethylene titanate, isopropyloxy tris(dioctyl pyrophosphate) titanate, tetraisopropyl di(dioctyl phosphite) titanate, isopropyl tristearate titanate, 2-hydroxyethyl methacrylate phosphate, octadecyl phosphate, dipropyl phenyl phosphate, triethyl phenyl phosphate, epoxypropyl phosphate triester, epoxyphenyl phosphate, aminomethyl phosphate coupling agent, etc.

[0021] In a preferred embodiment, the PBO composite fiber may further include a flame retardant.

[0022] In a preferred embodiment, the flame retardant may be one or more combinations of phosphorus-based flame retardants, nitrogen-based flame retardants, halogen-based flame retardants, inorganic oxide flame retardants, inorganic hydroxide flame retardants, borate flame retardants, sulfonate flame retardants, silicon-based flame retardants, and intumescent flame retardants. For example, the flame retardant may be selected from aluminum hydroxide, magnesium hydroxide, zinc borate, barium metaborate, antimony trioxide, antimony pentoxide, aluminum oxide, magnesium oxide, dibromomethane, trichlorobromomethane, dichlorobromomethane, octabromodiphenyl oxide, pentabromoethylbenzene, tetrabromobisphenol A, brominated polystyrene, decabromodiphenyl ether, hexabromocyclododecane, chlorinated paraffin, halocyclohexane, ammonium phosphate, tributyl phosphate, tris(2-ethylhexyl) phosphate, tris(2-chloroethyl) phosphate, tris(2,3-dichloropropyl) phosphate, tris(2,3-dichloropropyl) phosphate, tris(2,3-dichloropropyl) phosphate, tris(2,3-dichloropropyl) phosphate, etc. One or more of the following: (3-dibromopropyl) ester, toluene-diphenyl phosphate, tricresyl phosphate, triphenyl phosphate, (2-ethylhexyl)-diphenyl phosphate, phosphazene compounds, tris(dibromopropyl) phosphate, melamine, melamine cyanurate, cyclophosphamide polymers, polyphosphates, ammonium polyphosphate, melamine polyphosphate, urea, dicyandiamide, silicone oil, silicone resin, silicates, pentaerythritol, and intumescent graphite flame retardants.

[0023] In a preferred embodiment, the flame retardant may contain an intumescent flame retardant and a synergistic flame retardant (also known as a synergistic flame retardant). Preferably, the intumescent flame retardant and the synergistic flame retardant are each independently selected from one or more combinations of the aforementioned flame retardants. More preferably, the intumescent flame retardant is selected from one or more combinations of phosphorus-based intumescent flame retardants and nitrogen-based intumescent flame retardants (e.g., phosphorus-nitrogen intumescent flame retardants containing both phosphorus and nitrogen), and the synergistic flame retardant is selected from phosphorus-based flame retardants.

[0024] In a preferred embodiment, the weight ratio of the intumescent flame retardant to the synergistic flame retardant is preferably (50-10):1, more preferably (40-15):1, and even more preferably (30-20):1.

[0025] In a preferred embodiment, the PBO composite fiber is prepared by the method described in the second aspect of the present invention.

[0026] A second aspect of the present invention is to provide a method for preparing the above-mentioned PBO composite fiber, comprising: The fibers contained in PBO composite fibers are mixed to form a mixed roll; Spinning is performed to obtain yarn; The yarn is impregnated with finishing solution to absorb the finishing solution, and then rolled to remove part of the finishing solution; Dry the rolled yarn.

[0027] In a preferred embodiment, the fibers contained in the PBO composite fiber are equilibrated under constant temperature and humidity conditions before mixing.

[0028] In a preferred embodiment, the constant temperature condition is: 20-25°C.

[0029] In a preferred embodiment, the constant humidity condition is: relative humidity of 50%-70%, such as 55%, 60%, or 65%.

[0030] In a preferred embodiment, the balancing process takes no less than 24 hours.

[0031] In a preferred embodiment, the fibers contained in the PBO composite fiber are opened (preferably to form single fibers) before mixing.

[0032] In a preferred embodiment, the fibers contained in the PBO composite fiber are mixed in a blending machine. More preferably, the blending machine is selected from a multi-compartment blending machine or a turbine blender.

[0033] In a preferred embodiment, the fibers contained in the PBO composite fiber are mixed in at least two cycles, more preferably at least three cycles.

[0034] In a preferred embodiment, the spinning is performed using a rotor spinning (or air-jet spinning) method.

[0035] In a preferred embodiment, the spinning process includes sequential steps of carding, drawing, roving, and spinning.

[0036] In a preferred embodiment, the spinning step employs Sirospinning.

[0037] In a preferred embodiment, during the spinning process, the spindle speed in the fine spinning step is preferably 10,000-15,000 r / min, more preferably 10,000-14,000 r / min, such as 10,000 r / min, 11,000 r / min, 12,000 r / min, 13,000 r / min, 14,000 r / min, or 15,000 r / min.

[0038] In a preferred embodiment, during the spinning process, the spinning twist coefficient in the fine spinning step is 300-400, preferably 300-380, more preferably 310-380, such as 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400.

[0039] In a preferred embodiment, the finishing liquid may also contain the aforementioned penetrant.

[0040] In a preferred embodiment, the concentration of the penetrant in the finishing solution is 1-5 g / L, more preferably 1.2-4.5 g / L, and even more preferably 1.5-4 g / L (e.g., 1.8 g / L, 2 g / L, 2.3 g / L, 2.5 g / L, 2.8 g / L, 3 g / L, 3.2 g / L, 3.5 g / L, 3.7 g / L).

[0041] In a preferred embodiment, the finishing liquid may also contain the aforementioned antistatic agent.

[0042] In a preferred embodiment, the concentration of the antistatic agent in the finishing solution is 0.01-5 g / L, more preferably 0.05-4.5 g / L, more preferably 0.1-4 g / L, more preferably 0.3-3.5 g / L, more preferably 0.5-3.3 g / L, and more preferably 0.8-3 g / L (e.g., 1.0 g / L, 1.3 g / L, 1.5 g / L, 1.8 g / L, 2 g / L, 2.3 g / L, 2.5 g / L, 2.8 g / L, 3 g / L).

[0043] In a preferred embodiment, the finishing liquid contains the flame retardant described above.

[0044] In a preferred embodiment, the flame retardant concentration in the finishing liquid is 100-300 g / L, more preferably 120-280 g / L, and even more preferably 150-260 g / L.

[0045] In a preferred embodiment, the finishing liquid comprises the above-described intumescent flame retardant and the above-described synergistic flame retardant.

[0046] In a preferred embodiment, the concentration of the intumescent flame retardant in the finishing liquid is 150-250 g / L (e.g., 160 g / L, 170 g / L, 180 g / L, 190 g / L, 200 g / L, 210 g / L, 220 g / L, 230 g / L, 240 g / L, 250 g / L); and the concentration of the synergistic flame retardant is 5-15 g / L (e.g., 6 g / L, 7 g / L, 8 g / L, 9 g / L, 100 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L).

[0047] In a preferred embodiment, the pH value of the finishing solution is 5.5-6.5 (e.g., 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5).

[0048] In a preferred embodiment, the pH value of the finishing solution can be adjusted by an acid, such as an inorganic acid or an organic acid, preferably a saturated organic acid. For example, the inorganic acid can be hydrochloric acid, phosphoric acid, nitric acid, sulfuric acid, phosphorous acid, sulfurous acid, etc. The organic acid can be carboxylic acid, sulfonic acid, phosphonic acid, sulfinic acid, thiocarboxylic acid, etc. More preferably, the acid can be formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, succinic acid, valeric acid, glutaric acid, hexanoic acid, adipic acid, heptanoic acid, pimelic acid, caprylic acid, nonanoic acid, decanoic acid, benzoic acid, citric acid, tartaric acid, malic acid, quinic acid, salicylic acid, methanesulfonic acid, ethylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.

[0049] In a preferred embodiment, the impregnation and rolling can be performed independently and more than once, and the impregnation and rolling are performed alternately, for example, two impregnations and two rollings, using the steps of impregnation-rolling-impregnation-rolling.

[0050] In a preferred embodiment, the rolling allowance is 65-90%, more preferably 70-85%, and even more preferably 75-80%.

[0051] In a preferred embodiment, the drying temperature is 150-200°C, such as 160°C, 170°C, 180°C, etc.

[0052] In a preferred embodiment, the drying time is 1-10 minutes, more preferably 2-9 minutes, even more preferably 3-8 minutes, such as 4 minutes, 5 minutes, 6 minutes, or 7 minutes.

[0053] In a preferred embodiment, the rolled yarn is pre-dried before being dried, and the pre-drying temperature is lower than the drying temperature.

[0054] In a preferred embodiment, the pre-drying temperature is 80-120°C, such as 90°C, 100°C, 110°C, etc.

[0055] In a preferred embodiment, the pre-drying time is 1-5 minutes, more preferably 2-5 minutes, such as 2 minutes, 3 minutes, 4 minutes, or 5 minutes.

[0056] In a preferred embodiment, the drying and pre-drying are carried out independently in an inert gas atmosphere, preferably nitrogen, argon, etc.

[0057] In a preferred embodiment, the dried yarn is further wound into bobbins to obtain packaged yarn.

[0058] In a preferred embodiment, prior to blending, the BPO fibers are coated with a base oil agent, which includes a lubricant and the antistatic agent.

[0059] In a preferred embodiment, the base oil content is 0.3-0.5 wt%.

[0060] In a preferred embodiment, the filament is cut into short fibers before blending. Preferably, the short fibers can be of uniform length or within a certain range (e.g., 30-80 mm, preferably 35-70 mm, such as 38 mm, 40 mm, 45 mm, 51 mm, 56 mm, 60 mm, 64 mm).

[0061] In a preferred embodiment, one or more of the BPO fiber, para-aramid fiber, and flame-retardant adhesive fiber (preferably at least BPO fiber) are further subjected to surface modification treatment before blending. The surface modification treatment is performed by applying the "coupling agent oil" (or coupling agent) by impregnation or spraying.

[0062] In a preferred embodiment, the application of the "coupling agent oil" may be performed before, after, or simultaneously with the application of the base oil, but is preferably performed after the application of the base oil.

[0063] In a preferred embodiment, the oiling rate of the "coupling agent oil" is 0.1%-2wt%.

[0064] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1) Synergistic performance advantages: PBO fiber provides core strength and modulus; para-aramid compensates for the poor abrasion resistance of PBO and further enhances the overall thermal stability and toughness; flame-retardant viscose fiber not only provides an additional flame-retardant pathway (condensed phase flame retardancy), improves the moisture absorption, breathability and dyeability of the fiber assembly, but also acts as an "adhesive", which helps to more firmly bind the various component fibers together after baking.

[0065] 2) Cost advantage: By introducing lower-priced para-aramid and flame-retardant viscose, the high cost of pure PBO fiber is significantly reduced, making the product more competitive in the market.

[0066] 3) Technological Innovation Advantages: The method of this invention adopts a secondary flame-retardant enhancement mode of "blending + finishing". Blending provides basic flame retardancy from the fiber itself (intrinsic flame retardancy), while the subsequent impregnation and baking process constructs a robust intumescent char-retaining layer inside and on the surface of the yarn, achieving dual flame-retardant protection, resulting in a more durable and reliable flame-retardant effect. Baking under nitrogen protection effectively prevents the oxidative degradation of fibers such as PBO at high temperatures.

[0067] 4) Product application advantages: The final yarn has extremely excellent comprehensive performance, with strength >20cN / dtex, modulus >500cN / dtex, limiting oxygen index (LOI) >45%, and also has excellent abrasion resistance and thermal stability, making it an ideal material for preparing high-end special protective textiles. Detailed Implementation

[0068] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples further illustrate the invention in detail. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0069] It should be noted that the terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0070] Example 1: The composition by weight percentage is: 40% PBO fiber, 40% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0071] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a blending machine to be mixed evenly to form a blended roll.

[0072] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 12000r / min, twist coefficient 350), to obtain a 30-count blended yarn.

[0073] The flame retardant finishing liquid includes: 200 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0074] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0075] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0076] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0077] Table 1. Technical Effects of the Invention Test Project unit Example 1 PBO fiber para-aramid fibers Flame-retardant viscose fiber Fracture strength cN / dtex 24.5 38.0 20 3 Limiting Oxygen Index (LOI) % 48 68 29 28 abrasion resistance class Level >=4 Level >=4 Level >=4 <= Level 3 The abrasion resistance test method is the Martindale method, referring to GB / T 4802.2-1997.

[0078] Example 2: The composition by weight percentage is: 50% PBO fiber, 25% para-aramid fiber, and 25% flame-retardant viscose fiber.

[0079] The three types of fibers were placed in a standard temperature and humidity environment of 23±2℃ and 65±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a cotton blending machine to be mixed evenly to form a blended roll.

[0080] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 14000r / min, twist coefficient 360) to obtain blended yarn.

[0081] The flame retardant finishing liquid includes: 200 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0082] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0083] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0084] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0085] Example 3: The composition by weight percentage is: 60% PBO fiber, 20% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0086] The three types of fibers were placed in a standard temperature and humidity environment of 21±2℃ and 66±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a cotton blending machine to be mixed evenly to form a blended roll.

[0087] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 11000r / min, twist coefficient 350) to obtain blended yarn.

[0088] The flame retardant finishing liquid includes: 200 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0089] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0090] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0091] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0092] Example 4: The composition by weight percentage is: 25% PBO fiber, 45% para-aramid fiber, and 30% flame-retardant viscose fiber.

[0093] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 65±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a cotton blending machine to be mixed evenly to form a blended roll.

[0094] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 11000r / min, twist coefficient 370) to obtain blended yarn.

[0095] The flame retardant finishing liquid includes: 200 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0096] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0097] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0098] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0099] Example 5: The composition by weight percentage is: 25% PBO fiber, 50% para-aramid fiber, and 25% flame-retardant viscose fiber.

[0100] The three types of fibers were placed in a standard temperature and humidity environment of 23±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a cotton blending machine to be mixed evenly to form a blended roll.

[0101] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 14000r / min, twist coefficient 310) to obtain blended yarn.

[0102] The flame retardant finishing liquid includes: 200 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0103] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0104] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0105] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0106] Example 6: The composition by weight percentage is: 40% PBO fiber, 40% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0107] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a blending machine to be mixed evenly to form a blended roll.

[0108] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 12000r / min, twist coefficient 350), to obtain a 30-count blended yarn.

[0109] The flame retardant finishing liquid includes: 160 g / L of phosphorus-nitrogen intumescent flame retardant, 13 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0110] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0111] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0112] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0113] Example 7: The composition by weight percentage is: 40% PBO fiber, 40% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0114] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a blending machine to be mixed evenly to form a blended roll.

[0115] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 12000r / min, twist coefficient 350), to obtain a 30-count blended yarn.

[0116] The flame retardant finishing liquid includes: 180 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0117] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0118] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0119] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0120] Example 8: The composition by weight percentage is: 40% PBO fiber, 40% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0121] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a blending machine to be mixed evenly to form a blended roll.

[0122] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 12000r / min, twist coefficient 350), to obtain a 30-count blended yarn.

[0123] The flame retardant finishing liquid includes: 230 g / L of phosphorus-nitrogen intumescent flame retardant, 8 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0124] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0125] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0126] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0127] Example 9: The composition by weight percentage is: 40% PBO fiber, 40% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0128] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a blending machine to be mixed evenly to form a blended roll.

[0129] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 12000r / min, twist coefficient 350), to obtain a 30-count blended yarn.

[0130] The flame retardant finishing liquid includes: 220 g / L of phosphorus-nitrogen intumescent flame retardant, 12 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0131] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0132] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0133] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0134] Example 10: The composition by weight percentage is: 40% PBO fiber, 40% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0135] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a blending machine to be mixed evenly to form a blended roll.

[0136] Spinning includes: carding → drawing (two stages) → roving → spinning (using Siro spinning process, spindle speed 12000r / min, twist coefficient 350), to obtain a 30-count blended yarn.

[0137] The flame retardant finishing liquid includes: 200 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine polyphosphate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0138] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0139] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0140] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0141] Example 9 The composition by weight percentage is: 40% PBO fiber, 40% para-aramid fiber, and 20% flame-retardant viscose fiber.

[0142] A base oil is applied to the three types of fiber filaments. The base oil includes a lubricant (such as a high molecular weight polyether) and an antistatic agent (such as a quaternary ammonium salt antistatic agent). The oiling rate is controlled at 0.3-0.5 wt%.

[0143] The three types of fiber filaments are cut into short fibers of uniform length (e.g., 38mm, 51mm) to reduce extra-long and double-long fibers.

[0144] Surface modification of BPO fibers can be achieved by impregnation or spraying with a coupling agent oil (such as a silane coupling agent or a phosphate ester coupling agent). The oiling rate of the coupling agent oil is 0.1%-2%.

[0145] The three types of fibers were placed in a standard temperature and humidity environment of 22±2℃ and 63±2% for 24 hours. Then, they were opened separately by an opening machine and fed into a blending machine to be mixed evenly to form a blended roll.

[0146] Spinning is performed using rotor spinning (or air-jet spinning). This method is relatively lenient in terms of fiber length uniformity, resulting in yarns with less hairiness and more evenness, making it more suitable for rigid fibers such as PBO.

[0147] The flame retardant finishing liquid includes: 200 g / L of phosphorus-nitrogen intumescent flame retardant, 10 g / L of melamine cyanurate, 2 g / L of penetrant JFC, and pH adjusted to 6.0 with acetic acid.

[0148] The flame retardant finishing liquid is placed in the padding tank, and the yarn is passed through the padding tank for two dips and two nips (75% padding rate).

[0149] Then, pre-dry at 100℃ for 3 minutes, and then transfer to a nitrogen-filled baking machine to bake at 160℃ for 5 minutes to obtain yarn.

[0150] Finally, the yarn is wound into coils to obtain the finished flame-retardant yarn.

[0151] The product obtained in this embodiment shows reduced damage, improved mixing uniformity, and enhanced yarn strength and evenness. The "base oil" and "coupling agent oil" can: 1) improve processability, meeting the requirements of subsequent fiber opening and blending; and 2) improve the interfacial bonding between PBO and resins or other fibers, ensuring "interfacial stability." Therefore, this embodiment establishes a simpler, more efficient, and controllable production process for PBO staple fiber blended yarn, making it more suitable for large-scale production and stable quality control.

[0152] The specific embodiments of the present invention have been described in detail above, but they are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. A PBO composite fiber, characterized in that, It contains PBO fiber, para-aramid fiber, and flame-retardant viscose fiber, with PBO fiber accounting for at least 20% by weight.

2. The PBO composite fiber according to claim 1, characterized in that, The monofilament strength of PBO fiber is ≥5.0 GPa, and the monofilament modulus of PBO fiber is ≥180 GPa.

3. The PBO composite fiber according to claim 1, characterized in that, In the PBO composite fiber, the weight content of PBO fiber is 20-80%, the weight content of para-aramid fiber is 15-55%, and the weight content of flame-retardant viscose fiber is 5-35%.

4. The PBO composite fiber according to claim 1, characterized in that, The PBO composite fiber also includes one or more of the following: a penetrant, an antistatic agent, a flame retardant, a lubricant, and a coupling agent.

5. The PBO composite fiber according to claim 4, characterized in that, The penetrant is selected from one or more of fatty alcohol polyoxyethylene ethers and alkylphenol polyoxyethylene ethers; and / or The flame retardant may be one or a combination of phosphorus-based flame retardants, nitrogen-based flame retardants, halogen-based flame retardants, inorganic oxide flame retardants, inorganic hydroxide flame retardants, borate flame retardants, sulfonate flame retardants, silicon-based flame retardants, and intumescent flame retardants.

6. A method for preparing the PBO composite fiber according to claim 1, characterized in that, include: The fibers contained in PBO composite fibers are mixed to form a mixed roll; Spinning is performed to obtain yarn; The yarn is impregnated with finishing solution to absorb the finishing solution, and then rolled to remove part of the finishing solution; Dry the rolled yarn.

7. The method according to claim 6, characterized in that, Prior to blending, one or more of the BPO fibers, para-aramid fibers, and flame-retardant adhesive fibers are applied with a base oil agent, which includes a lubricant and the antistatic agent; the oiling rate of the base oil agent is 0.3-0.5 wt%. Before blending, one or more of the BPO fiber, para-aramid fiber, and flame-retardant adhesive fiber undergo surface modification treatment. This surface modification treatment involves applying a coupling agent oil by impregnation or spraying; the oiling rate of the coupling agent oil is 0.1%-2 wt%. The "coupling agent oil" is applied before, after, or simultaneously with the application of the base oil.

8. The method according to claim 6, characterized in that, The pH value of the finishing solution is 5.5-6.5; and / or The finishing solution also contains a penetrant, and the concentration of the penetrant in the finishing solution is 1-5 g / L; The finishing liquid also contains a flame retardant, and the concentration of the flame retardant in the finishing liquid is 100-300 g / L.

9. The method according to claim 6, characterized in that, The impregnation and rolling can be performed independently and repeatedly, and the impregnation and rolling are carried out alternately, with a rolling allowance of 65-90%.

10. The method according to claim 6, characterized in that, The rolled yarn is pre-dried before being fully dried; the pre-drying temperature is 80-120℃ and the pre-drying time is 1-5 minutes; the drying temperature is 150-200℃ and the drying time is 1-10 minutes; the drying and pre-drying are carried out independently in an inert gas atmosphere.