Non-crimp continuous endless tow phenolic fiber and process equipment, preparation method and application thereof

Abstract

The invention provides process equipment for non-crimp continuous endless tow phenolic fibers, which comprises a spinning unit, a tow guide unit and a tow collecting unit, the spinning unit comprises a double-screw mechanism, a gear pump and a spinneret plate, the gear pump is arranged between the double-screw mechanism and the spinneret plate, the tow guide unit comprises a plurality of tow guide rollers and an oiling agent tank, the oiling agent tank is arranged in the spinning unit, and the oiling agent tank is arranged in the spinning unit. The oiling agent tank is arranged between two adjacent godets, the silk collecting unit comprises a tension roller and a silk collecting roller, and the tension roller is arranged between the godets and the silk collecting roller. The mixing effect and stability of raw material melting can be improved through the double-screw mechanism in the process equipment, the flexibility of phenolic resin precursor bundles can be improved through the oiling agent tank, and the continuity and uniformity of the phenolic resin precursor bundles can be guaranteed through cooperation of the gear pump and the tension roller; the combination of the tension roller and the take-up roller can avoid fluctuation and instability of take-up of a take-up gun in related technologies. The invention further discloses the non-crimp continuous endless tow phenolic fiber and a preparation method and application thereof.

Description

Technical Field

[0001] The invention belongs to the technical field of phenolic fibers, and in particular relates to a non-crimped continuous filament bundle phenolic fiber and a process equipment, a preparation method and an application thereof. Background Art

[0002] At present, phenolic fiber is a three-dimensional cross-linked organic fiber made of phenolic resin. It has broad application prospects in flame retardancy, high-temperature heat protection, thermal insulation, insulation and sound insulation, chemical protection, and indoor high-end flame retardant decorative materials such as aircraft and submarines. Internationally, only Kynol Company of Japan has achieved industrial production and product sales of phenolic fiber. Domestic phenolic fiber is still in the laboratory research stage, and is mainly short-fiber with fixed length. Compared with long-filament bundle fibers, short fibers have obvious deficiencies in the manufacture of textiles and weaving fabrics.

[0003] Regarding the reports on filament bundle phenolic fibers, patents CN115386975A and CN115341298A use two-component raw materials for melt spinning, and obtain curly phenolic filaments through the difference in thermal properties of the two components. Compared with non-curled long fibers, the curly filament bundles prepared by this method will have certain limitations on the performance and application of the fibers; then, the content of organic polymers with low heat resistance mixed in during the preparation process is too high, which will have a significant negative impact on the performance advantages of phenolic fibers such as heat resistance and flame retardancy; secondly, the airflow collector used will have the problem of filament suction stability, which will significantly affect the uniformity of the fibers; and there is no oiling agent unit in the preparation system, and there will be problems such as fiber bundle dispersion and many hairy fibers in the fiber bundle, and high-quality filament bundle phenolic fibers cannot be obtained.

[0004] Although wet spinning can theoretically produce phenolic fibers in the form of filament bundles, existing research shows that due to the lack of breakthroughs in the tow coagulation process, the shape and performance of the prepared fibers have obvious defects. The fibers are not regular round or elliptical shapes, and there are also obvious defects inside the fibers. The performance in all aspects is still a long way from practical application. Similarly, the wet spinning process also requires the addition of a large amount of organic spinning aids, which will have a significant negative impact on the heat resistance and flame retardancy of the fibers.

[0005] In order to solve the above technical problems, the present invention designs a non-crimped continuous filament bundle phenolic fiber and its process equipment, preparation method and application. Summary of the invention

[0006] The present invention provides a non-crimped continuous filament bundle phenolic fiber and its process equipment, preparation method and application. The filament bundle phenolic fiber prepared by the method has a circular cross section, few internal defects, a dense structure, outstanding heat resistance and flame retardancy, and is easy to be mass-produced industrially.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a process equipment for non-curled continuous filament bundle phenolic fiber, comprising a spinning unit, a guide wire unit and a collecting unit, the spinning unit comprising a twin-screw mechanism, a gear pump and a spinneret, the gear pump being arranged between the twin-screw mechanism and the spinneret, the guide wire unit comprising a guide wire roller and an oil agent tank, the number of the guide wire rollers being multiple, the oil agent tank being arranged between two adjacent guide wire rollers, the collecting unit comprising a tension roller and a collecting roller, the tension roller being arranged between the guide wire roller and the collecting roller.

[0008] Based on the above technical solution, the temperature of the twin-screw mechanism is 120-220°C.

[0009] Based on the above technical solution, the pressure provided by the gear pump is 0.5-10MPa.

[0010] Based on the above technical solution, the number of spinneret holes of the spinneret is 250 holes, 500 holes, 750 holes or 1000 holes.

[0011] Based on the above technical solution, the tension of the tension roller is 0.02-0.2N.

[0012] In a second aspect, the present application provides a method for preparing non-crimped continuous filament bundle phenolic fiber, which is a process equipment for the non-crimped continuous filament bundle phenolic fiber described in any one of the above embodiments, comprising the following steps: mixing phenolic monomers, aldehyde monomers, modifiers and catalysts, heating and reacting to obtain modified spinnable thermoplastic phenolic resin; adding the modified spinnable thermoplastic phenolic resin into a twin-screw mechanism for melting, removing free phenol and low-polymerization degree small molecules, and conveying it to a gear pump, which pressurizes the melt and extrude it through a spinneret to obtain raw yarn; stretching and bundling the raw yarn through a guide roller and an oil tank, applying a fixed tension through a tension roller, and winding it through a collection roller to obtain a filament bundle phenolic resin raw yarn bundle; placing the raw yarn bundle and the collection roller in a curing liquid for curing and cross-linking, placing it in an acetic acid and acetic anhydride solution for acetylation of the phenolic hydroxyl group, washing, drying, and finally combining the yarns to obtain a non-crimped continuous filament bundle phenolic fiber.

[0013] Based on the above technical scheme, the phenolic monomer is one or more of phenol, bisphenol A, cresol, hydroquinone, resorcinol, diphenyl ether, vinyl phenol and xylenol, the aldehyde monomer is one or more of formaldehyde and paraformaldehyde, the modifier is one or more of epichlorohydrin, nonylphenol, epoxy cardanol, triphenyl phosphate and xylene, and the catalyst is oxalic acid or hydrochloric acid.

[0014] Based on the above technical solution, the content of free phenol is less than or equal to 0.5%.

[0015] In a third aspect, the present application provides a non-crimped continuous filament bundle phenolic fiber, which is prepared according to the preparation method of the non-crimped continuous filament bundle phenolic fiber described in any one of the above embodiments.

[0016] In a fourth aspect, the present application provides a non-crimped continuous filament bundle phenolic fiber obtained by the preparation method described in any one of the above embodiments, and its application in flame-retardant decorative materials.

[0017] Compared with the related art, the beneficial effects of the present invention are as follows: The present invention spins out raw yarn by arranging a spinning mechanism, and the twin-screw mechanism melts the raw materials to obtain a molten material, which is then conveyed to a gear pump. The setting of the gear pump can apply pressure to avoid unstable pressure of the twin-screw, and the gear pump applies pressure to provide a continuous and stable pressure to the spinneret to ensure the continuity and uniformity of spinning. The setting of the guide roller is for the collection and drawing of the raw yarn filament bundle, and the function of the oil agent tank is to bundle and flexibilize the raw yarn filament bundle. The function of the tension roller is to provide a constant drawing force for spinning, and under the action of the constant extrusion pressure of the gear pump and the constant drawing force of the tension roller, the continuity and uniformity of the raw yarn filament bundle are ensured, and the function of the collection roller is to collect the phenolic resin raw yarn of the filament bundle and regularly wind it on the collection roller. The combination of the tension roller and the collection roller avoids the fluctuation and instability of the collection of the yarn by the collection gun in the related art, and the collection roller adopts corrosion-resistant materials such as tetrafluoroethylene to ensure the integrity of the collection roller in the acidic curing liquid. Finally, non-crimped continuous filament bundle phenolic fibers with a circular cross section, few internal defects, a dense structure, and higher strength and elongation at break can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0019] Figure 1 It is a structural schematic diagram of a process equipment for producing non-crimped continuous filament bundle phenolic fibers provided by the present invention; Figure 2 The present invention provides a method for preparing non-crimped continuous filament bundle phenolic fiber, and shows a scanning electron microscope image of a fiber cross section.

[0020] In the figure: 1. Twin-screw mechanism; 2. Gear pump; 3. Spinneret; 4. Godet roller; 5. Oil tank; 6. Tension roller; 7. Collection roller. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and examples: Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0024] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, instruments, etc. used in the following examples are all commercially available unless otherwise specified.

[0025] Combination Figure 1 As shown, the present invention provides a process equipment for non-crimped continuous filament bundle phenolic fiber, including a spinning unit, a guide wire unit and a collection unit, the spinning unit includes a twin-screw mechanism 1, a gear pump 2 and a spinneret 3, the gear pump 2 is arranged between the twin-screw mechanism 1 and the spinneret 3, the guide wire unit includes a guide wire roller 4 and an oil agent tank 5, the number of the guide wire rollers 4 is multiple, the oil agent tank 5 is arranged between two adjacent guide wire rollers 4, the collection unit includes a tension roller 6 and a collection roller 7, the tension roller 6 is arranged between the guide wire roller 4 and the collection roller 7.

[0026] The present invention spins raw yarn by setting a spinning mechanism. The twin-screw mechanism 1 melts the raw material to obtain a molten material, which is then transported to the gear pump 2. The gear pump 2 is set to pressurize the raw material to avoid unstable pressure of the twin-screw. The gear pump 2 is used to pressurize the spinneret 3 to provide a continuous and stable pressure to ensure the continuity and uniformity of spinning. The guide roller 4 is set to collect and draw the raw yarn filament bundle. The number of the guide rollers 4 is 3-6. The oil tank 5 is used to facilitate the bundling and flexibility of the raw yarn filament bundle. The position of the oil tank 5 can be on the second guide roller 4. Between any two of the last guide rollers 4, the tension roller 6 provides a constant drafting force for spinning. Under the action of the constant extrusion pressure of the gear pump 2 and the constant drafting force of the tension roller 6, the continuity and uniformity of the raw filament bundle are ensured. The collection roller 7 collects the phenolic resin raw filaments of the filament bundle and winds them regularly on the collection roller 7. The combination of the tension roller 6 and the collection roller 7 avoids the fluctuation and instability of the collection of the wire by the collection gun in the related technology, and the collection roller 7 is made of corrosion-resistant materials such as tetrafluoroethylene to ensure the integrity of the collection roller 7 in the acidic curing liquid.

[0027] Based on the above technical solution, the temperature of the twin-screw mechanism 1 is 120-220°C.

[0028] Based on the above technical solution, the pressure provided by the gear pump 2 is 0.5-10 MPa.

[0029] Based on the above technical solution, the number of spinneret holes of the spinneret plate 3 is 250 holes, 500 holes, 750 holes or 1000 holes.

[0030] Based on the above technical solution, the tension of the tension roller 6 is 0.02-0.2N.

[0031] The present invention also provides a method for preparing non-crimped continuous filament bundle phenolic fiber, which is applied to a process equipment for preparing non-crimped continuous filament bundle phenolic fiber according to any one of the above embodiments, comprising the following steps: A phenolic monomer, an aldehyde monomer, a modifier and a catalyst are mixed and heated to react to obtain a modified spinnable thermoplastic phenolic resin; The modified spinnable thermoplastic phenolic resin is added to the twin-screw mechanism 1 to be melted, free phenol and low-polymerization degree small molecules are removed, and the melt is transported to the gear pump 2. After the gear pump 2 pressurizes the melt, it is extruded through the spinneret 3 to obtain the raw yarn; The raw yarn is drawn and bundled through the godet roller 4 and the oil tank 5, a constant tension is applied through the tension roller 6, and the raw yarn is wound through the take-up roller 7 to obtain a filament bundle of phenolic resin raw yarn; The raw yarn bundle and the collection roller 7 are placed in a curing liquid for curing and cross-linking, and are placed in an acetic acid and acetic anhydride solution for acetylation of the phenolic hydroxyl groups. The raw yarn bundle and the collection roller 7 are then washed and dried. Finally, the non-crimped continuous filament bundle phenolic fiber is obtained by doubling.

[0032] The modified spinnable thermoplastic phenolic resin is used as the raw material in the present invention because the strength and toughness of the phenolic precursor made of ordinary phenolic resin as the raw material are extremely poor. Although it can meet the minimum requirements of short fiber spinning, it cannot meet the drawing, bundling, directional wire guiding, winding and wire collection of the phenolic precursor of the filament bundle. The present invention adopts phenolic monomers and aldehyde monomers to heat and react with the modifier and the catalyst together, and introduces and increases flexible groups or flexible chains in the phenolic resin through the internal toughening mechanism of alkyl etherification, alkylation and etherification of phenolic hydroxyl groups of the phenolic resin by the method of grafting and block polymerization, so as to achieve the strengthening and toughening of the phenolic resin precursor.

[0033] In the present invention, the raw yarn bundle together with the collection roller 7 is heated and cured and cross-linked in the curing liquid, so as to cure and cross-link the raw yarn bundle in a tensioned state, thereby avoiding the disadvantage of curing and cross-linking in a relaxed state after the phenolic resin raw yarn is taken off the roller in the conventional curing process, which affects the mechanical properties of the fiber. The acetylation of the phenolic hydroxyl group described in the present invention is because the phenolic hydroxyl group in phenolic resin is easily oxidized to quinone, thereby affecting the fiber performance and appearance. The acetylation reaction of the phenolic hydroxyl group of the fiber with acetic acid and acetic anhydride solution can improve the oxidation resistance and strength of the phenolic fiber. Figure 2 As shown, the cross section of the filament bundle phenolic fiber prepared in the present application is circular, the fiber has few internal defects and a dense structure.

[0034] Specifically, in the step of removing free phenol and small molecules with a low degree of polymerization, the degree of polymerization of the small molecules with a low degree of polymerization is ≤2.

[0035] The purpose of cleaning and drying is to remove harmful chemical components such as formaldehyde, hydrochloric acid, acetic acid and acetic anhydride remaining in the curing and cross-linking process.

[0036] The function of doubling is to achieve the target specification of the tow through doubling. After doubling, non-crimped continuous filament tow high-performance phenolic fibers with specifications of 0.5K, 1K, 3K and 6K can be obtained.

[0037] Based on the above technical scheme, the phenolic monomer is one or more of phenol, bisphenol A, cresol, hydroquinone, resorcinol, diphenyl ether, vinyl phenol and xylenol, the aldehyde monomer is one or more of formaldehyde and paraformaldehyde, the modifier is one or more of epichlorohydrin, nonylphenol, epoxy cardanol, triphenyl phosphate and xylene, and the catalyst is oxalic acid or hydrochloric acid.

[0038] Among them, preferably, the modifier is epichlorohydrin and nonylphenol. When the modifier is epichlorohydrin, after chemical reaction with the phenolic resin, epoxy groups are introduced through etherification of phenolic hydroxyl groups, thereby increasing the proportion of flexible segments in the phenolic resin, thereby improving the toughness and spinnability of the modified spinnable thermoplastic phenolic resin.

[0039] Based on the above technical solution, the content of free phenol is less than or equal to 0.5%. Since free phenol and phenolic resin are two phases that do not mix with each other, the presence of free phenol will cause many fiber breakages and the spinning cannot be carried out continuously. Controlling the content of free phenol below 0.5% can avoid the free phenol content being too high to affect the quality and performance of subsequent products.

[0040] The present invention also provides a non-crimped continuous filament bundle phenolic fiber, which is prepared according to the preparation method of the non-crimped continuous filament bundle phenolic fiber described in any one of the above embodiments.

[0041] The present invention also provides a non-crimped continuous filament bundle phenolic fiber obtained by the preparation method described in any one of the above embodiments, and its application in flame-retardant decorative materials.

[0042] Example 1 This embodiment provides a method for preparing non-crimped continuous filament bundle phenolic fiber, comprising the following steps: Phenol, bisphenol A, formaldehyde, nonylphenol and oxalic acid (molar ratio 0.5:0.5:0.85:0.05:0.015) were reacted at 95°C for 3.5 hours to synthesize a modified spinnable thermoplastic phenolic resin having a softening point greater than 110°C.

[0043] The modified spinnable thermoplastic phenolic resin is melted and light components are removed by a twin-screw mechanism 1, wherein the free phenol content is removed to 0.35%. The temperature of the twin screw is 170°C, and then the resin is transported to a gear pump 2, which is pressurized to 1.5 MPa. The resin is then transported to a spinneret 3 for extrusion, and the spinneret 3 has 500 spinneret holes.

[0044] The raw yarn spun from the spinneret hole is guided by the first wire guide roller 4 and the second wire guide roller 4 and then enters the oil agent tank 5 for bundling and flexibilization. Then, it passes through the third wire guide roller 4 and enters the tension roller 6. The tension roller 6 applies a tension of 0.75N and finally passes through the tetrafluoroethylene wire collection roller 7 for collection to obtain a long filament bundle of phenolic resin raw yarn regularly wound on the wire collection roller 7.

[0045] The raw yarn bundle is placed in a curing liquid of hydrochloric acid (15%) and formaldehyde (18%) together with the collecting roller 7 under the winding tension state, and the temperature is increased for curing and cross-linking. Then, it is placed in an acetic acid and acetic anhydride solution (molar ratio of 1:1) and phenolic hydroxyl acetylation reaction is carried out at 60°C for 1.5 hours. Then, it is washed with deionized water and dried to remove residual formaldehyde, hydrochloric acid, acetic acid, acetic anhydride, etc. Finally, the two rollers of yarn bundles are combined to obtain a non-curled continuous filament bundle of high-performance phenolic fiber with a specification of 1K, a diameter of 12μm, a strength of 220MPa, and an elongation at break of 20%.

[0046] Example 2 The synthesis method of this embodiment is the same as that of embodiment 1, and the same parts are omitted. The difference from embodiment 1 is that the phenol monomers are hydroquinone and cresol, the aldehyde monomer is polyoxymethylene, the modifiers are triphenyl phosphate and epichlorohydrin, the catalyst is hydrochloric acid (2% by weight of the reactants), the molar ratio of hydroquinone, cresol, polyoxymethylene, triphenyl phosphate, and epichlorohydrin is 0.3:0.7:0.88:0.07:0.02, the reaction conditions are 98°C for 3.0 hours, and the synthesized modified spinnable thermoplastic having a softening point greater than 130°C is The temperature of the phenolic resin twin-screw is 190°C, the gear pump 2 is pressurized to 3.0 MPa, the number of spinneret holes of the spinneret 3 is 750 holes, the tension roller 6 applies a tension of 0.15N, the curing liquid is hydrochloric acid (14%) and hexamethylenetetramine (16%), the molar ratio of acetic acid to acetic anhydride is 1:1.5, the acetylation reaction conditions of phenolic hydroxyl groups are 65°C for 2.0 hours, and finally the four-roller tow is combined to obtain a non-crimped continuous filament bundle high-performance phenolic fiber with a specification of 3K, a diameter of 15 μm, a strength of 280 MPa, and a breaking elongation of 30%.

[0047] Example 3 The synthesis method of this embodiment is the same as that of embodiment 1, and the same parts are omitted. The difference from embodiment 1 is that the phenol monomers are resorcinol, vinyl phenol and xylenol, the aldehyde monomers are formaldehyde and polyoxymethylene, the modifier is epoxy cardanol, the catalyst is hydrochloric acid, the molar ratio of resorcinol, vinyl phenol, xylenol, formaldehyde, polyoxymethylene, epoxy cardanol and hydrochloric acid is 0.3:0.3:0.4:0.4:0.45:0.05:0.012, the reaction conditions are 96°C for 4.5 hours, and the synthesized modified polyol with a softening point greater than 135°C can be obtained. Spinning thermoplastic phenolic resin, the temperature of the twin screw is 210°C, the gear pump 2 is pressurized to 2.0 MPa, the number of spinneret holes of the spinneret 3 is 250 holes, the tension roller 6 applies a tension of 0.05N, the curing liquid is hydrochloric acid (15%) and hexamethylenetetramine (15%), the molar ratio of acetic acid and acetic anhydride is 2:1, the acetylation reaction conditions of phenolic hydroxyl groups are 55°C for 3.0 hours, and finally the four-roller tow is combined to obtain a non-crimped continuous filament bundle high-performance phenolic fiber with a specification of 0.5K, a diameter of 10 μm, a strength of 250 MPa, and a breaking elongation of 25%.

[0048] Comparative Example 1 The synthesis method of this embodiment is the same as that of embodiment 1, and the same parts are omitted. The difference from embodiment 1 is that no modifier is added, and the last two rollers of tow are combined to obtain non-crimped continuous filament bundle high-performance phenolic fiber with specification 1K, diameter 12 μm, strength 160 MPa, and elongation at break 8%. Compared with the phenolic fiber obtained in embodiment 1, the strength and elongation at break are significantly reduced.

[0049] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments, and any changes or modifications made based on the present invention belong to the scope of protection claimed by the present invention.

Claims

1. A process equipment for producing non-crimped continuous filament bundle phenolic fiber, characterized in that: It includes a spinning unit, a wire guide unit and a wire collection unit. The spinning unit includes a twin-screw mechanism, a gear pump and a spinneret. The gear pump is arranged between the twin-screw mechanism and the spinneret. The wire guide unit includes a wire guide roller and an oil agent tank. There are multiple wire guide rollers. The oil agent tank is arranged between two adjacent wire guide rollers. The wire collection unit includes a tension roller and a wire collection roller. The tension roller is arranged between the wire guide roller and the wire collection roller.

2. The process equipment according to claim 1, characterized in that: The temperature of the twin-screw mechanism is 120-220°C.

3. The process equipment according to claim 1, characterized in that: The pressure provided by the gear pump is 0.5-10 MPa.

4. The process equipment according to claim 1, characterized in that: The number of the spinneret holes of the spinneret is 250 holes, 500 holes, 750 holes or 1000 holes.

5. The process equipment according to claim 1, characterized in that: The tension of the tension roller is 0.02-0.2N.

6. A method for preparing non-crimped continuous filament bundle phenolic fiber, applied to the process equipment for preparing non-crimped continuous filament bundle phenolic fiber according to any one of claims 1 to 5, characterized in that: The following steps are involved: A phenolic monomer, an aldehyde monomer, a modifier and a catalyst are mixed and heated to react to obtain a modified spinnable thermoplastic phenolic resin; The modified spinnable thermoplastic phenolic resin is added to a twin-screw mechanism for melting, free phenol and low-polymerization-degree small molecules are removed, and the melt is sent to a gear pump. The gear pump pressurizes the melt and then extrudes it through a spinneret to obtain raw yarn. The raw yarn is drawn and bundled through the guide roller and the oil tank, a certain tension is applied through the tension roller, and the raw yarn is wound through the collection roller to obtain a filament bundle of phenolic resin raw yarn; The raw yarn bundle and the collection roller are placed in a curing liquid for curing and cross-linking, and then placed in an acetic acid and acetic anhydride solution for acetylation of the phenolic hydroxyl groups. The fibers are then washed and dried, and finally the non-crimped continuous filament bundle phenolic fibers are obtained by doubling.

7. The preparation method according to claim 6, characterized in that: The phenolic monomer is one or more of phenol, bisphenol A, cresol, hydroquinone, resorcinol, diphenyl ether, vinyl phenol and xylenol; the aldehyde monomer is one or more of formaldehyde and paraformaldehyde; the modifier is one or more of epichlorohydrin, nonylphenol, epoxy cardanol, triphenyl phosphate and xylene; and the catalyst is oxalic acid or hydrochloric acid.

8. The preparation method according to claim 6, characterized in that: The content of free phenol is less than or equal to 0.5%.

9. A non-crimped continuous filament bundle phenolic fiber, characterized in that: The non-crimped continuous filament bundle phenolic fiber is prepared according to the method for preparing the non-crimped continuous filament bundle phenolic fiber according to any one of claims 6 to 8.

10. Use of the non-crimped continuous filament bundle phenolic fiber obtained by the preparation method according to any one of claims 6 to 8 in flame retardant decorative materials.

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