Microcapsule doped chemical fiber spinning fiber and preparation method thereof

Abstract

The invention relates to the technical field of chemical fiber, in particular to microcapsule-doped chemical fiber spinning fiber and a preparation method thereof.The preparation method of the microcapsule-doped chemical fiber spinning fiber comprises the following steps that flame-retardant microcapsules and dried polyester chips are mixed, spinning, cooling curing and monofilament bundling are conducted through a single-screw melt spinning machine, and the microcapsule-doped chemical fiber spinning fiber is obtained. Oiling and drafting to obtain the microcapsule doped chemical fiber spinning fiber. The flame-retardant microcapsules are added, ammonium polyphosphate in the core material is used as a gas source or an acid source during combustion, chitosan is used as a carbon source, and an amino zirconium organic framework is used as a catalytic charring agent to synergistically form a compact and stable expanded carbon layer, so that the heat insulation and oxygen insulation effects are improved, and the flame retardance of the fiber is improved; the micro gas contained in the microcapsule or the pressure generated by vaporization of the core material can be expanded in the screw extrusion filament outlet process, micro explosion is formed in the filament outlet process, a microporous filament structure is formed, the soft, light, breathable and high-hygroscopicity effects are achieved, and good application prospects are achieved.

Description

Technical Field

[0001] This invention belongs to the field of chemical fiber technology, specifically relating to a microcapsule-doped chemical fiber spinning fiber and its preparation method. Background Technology

[0002] Synthetic fibers are textile materials made from high-molecular compounds through special processes. They are characterized by light resistance, abrasion resistance, and easy washing, and are widely used in clothing, home furnishings, and other fields. Synthetic fibers are strong and durable, with high density and strong strength. They are wrinkle-resistant and require no ironing, resulting in fewer wrinkles after rubbing. Furthermore, their production cost is low, and the raw material price is lower than that of natural fibers, making them suitable for large-scale industrial production. Polyester fibers, especially polyethylene terephthalate (PET) fibers, have become the world's largest-produced and most widely used synthetic fibers due to their excellent mechanical properties, chemical resistance, and cost advantages. However, polyester fibers have a limiting oxygen index of only about 20-21%, classifying them as flammable materials. When burning, they produce severe molten dripping, easily igniting other items and spreading fires, posing a significant safety hazard.

[0003] Therefore, there is an urgent need for a fiber with good flame retardant properties. Summary of the Invention

[0004] The purpose of this invention is to provide a microcapsule-doped chemical fiber spinning fiber and its preparation method, in order to solve the technical problems in the prior art.

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

[0006] This invention provides a method for preparing microcapsule-doped chemical fiber spinning fibers, comprising the following steps:

[0007] Flame-retardant microcapsules are mixed with dried polyester chips, spun using a single-screw melt spinning machine, cooled and solidified, the monofilaments are bundled, oiled, and drawn to obtain microcapsule-doped chemical fiber spun fibers.

[0008] Preferably, the drying conditions are as follows: drying temperature is 130-140℃, drying time is 8-10h; the ratio of flame-retardant microcapsules to polyester chips is 5-10:95-190; mixing method: mixing at 400-600rpm for 40-50min; spinning temperature: zone 1 265℃, zone 2 275℃, zone 3 285℃, and the spinning chamber 280℃; cooling and curing method: cooling and curing under side-blowing conditions at 20-25℃; oiling method: using polyester oiling agent for oiling, with the oiling rate controlled at 0.5-0.7%; drawing method: initial drawing in an 80℃ hot water bath and final drawing on a 135℃ hot roller; the total draw ratio is 4.5-5.0.

[0009] Preferably, the method for preparing the flame-retardant microcapsules includes the following steps:

[0010] P1: Add styrene-maleic anhydride copolymer (SMA) to water, add triethanolamine to adjust the pH, then add flame retardant core material, first mechanically stir to pre-disperse, then ultrasonically treat to obtain an aqueous phase system, and place the aqueous phase system in a water bath at 65-75℃;

[0011] P2: Methyl methacrylate (MMA), ethylene glycol dimethacrylate (EGDMA), and azobisisobutyronitrile (AIBN) were mixed under mechanical stirring to obtain an oil phase; the oil phase was slowly added dropwise to the aqueous phase to continue emulsification, the stirring speed was reduced, the reaction was continued, the mixture was cooled to room temperature, washed, and vacuum dried to obtain flame-retardant microcapsules.

[0012] Preferably, in P1, the ratio of SMA, water, and flame-retardant core material is 25-50g:1.2-2.4L:10-20g; the pH value is adjusted to 5.0-5.5; the mechanical stirring pre-dispersion method is: mechanical stirring pre-dispersion at a speed of 600-1000rpm for 8-12min; the ultrasonic treatment time is 5-10min; and the water bath temperature is 65-75℃.

[0013] Preferably, in P2, the mechanical stirring speed is 1300-1700 rpm; the ratio of MMA, EGDMA, and AIBN is 200-400 mL: 20-40 g: 5-10 g; the emulsification time is 25-35 min; the stirring speed is reduced to 600-800 rpm; the reaction is continued at 65-75℃ for 5-7 h; the washing method is to wash with water by vacuum filtration, and then wash with ethanol 1-3 times; the drying method is to vacuum dry at 45-55℃ for 20-28 h.

[0014] Preferably, the method for preparing the flame-retardant core material includes the following steps:

[0015] S1: Add chitosan to an aqueous acetic acid solution and stir magnetically to obtain a chitosan solution; add ammonium polyphosphate to water, stir and sonicate to obtain an ammonium polyphosphate solution.

[0016] S2: Dissolve 2-aminoterephthalic acid and ZrCl4 in DMF, react, centrifuge, wash, and finally vacuum dry to obtain an aminozirconium organic framework;

[0017] S3: The aminozirconium organic framework is immersed in the chitosan solution prepared in S1. The precipitate is washed with water 2-4 times, and then immersed in the ammonium polyphosphate solution prepared in S1. The precipitate is washed with water 2-4 times. The assembly process is repeated 3-5 times to obtain the flame-retardant core material.

[0018] Preferably, in step S1, the ratio of chitosan, aqueous acetic acid solution, ammonium polyphosphate, and water is 10-20g:990-2000g:20-40g:980-1960g; the aqueous acetic acid solution has a mass fraction of 1wt%; the magnetic stirring time is 1.5-2.5h; and the ultrasonic treatment time is 8-12min.

[0019] Preferably, in S2, the ratio of 2-aminoterephthalic acid, ZrCl4, and DMF is 14-28g:12-14g:800-1600mL; the reaction method is to react at 115-125℃ for 10-14h; the washing method is to wash with methanol 4-6 times; and the vacuum drying method is to vacuum dry at 75-85℃ for 1.5-2.5h.

[0020] Preferably, in step S3, the soaking time is 5-7 minutes; the immersion time is 5-7 minutes.

[0021] Microcapsule-doped chemical fiber spun fibers were prepared using the aforementioned method.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. In the core material of this invention, ammonium polyphosphate serves as a gas or acid source during combustion, chitosan serves as a carbon source, and the aminozirconium organic framework serves as a catalytic char-forming agent to synergistically form a dense, stable, and expanding carbon layer, thereby improving the heat insulation and oxygen barrier effects and enhancing the flame retardancy of the fiber.

[0024] 2. By encapsulating the flame-retardant core material with a polymethyl methacrylate (PMMA) shell, the compatibility between the flame retardant and the polymer matrix is ​​improved, stress concentration points are reduced, and the high-temperature resistance of the microcapsule shell protects the flame-retardant core material at the high temperatures of melt spinning, preventing decomposition, deterioration, or premature reaction, thus ensuring the stability of the flame-retardant efficiency. Furthermore, the microcapsules encapsulate the flame retardant within the shell, preventing its migration and seepage to the fiber surface during long-term use or washing, ensuring the durability of the flame-retardant effect. These flame-retardant microcapsules can be directly mixed with polyester chips and melt-spun, making the operation simple.

[0025] 3. The spinning temperature setting of this application enables the microcapsule wall material to undergo a controllable micro-explosion at the moment the melt passes through the spinneret when it reaches its thermodynamic limit, utilizing the pressure generated by the vaporization of a small amount of gas inside or the core material. This precisely releases the nano-hybrid flame retardant into the fiber interior and near-surface region, while simultaneously forming micro- and nano-scale pores inside and on the fiber surface. This achieves spatial reconstruction of the fiber structure, causing the fiber macromolecules to crystallize in an oriented manner, improving mechanical properties, stabilizing the microporous structure formed by the micro-explosion, and ensuring the long-lasting flame retardant function. Furthermore, due to the formation of a multi-microporous filament structure, the filament fabric has softness, lightness, breathability, and high moisture absorption, showing promising application prospects. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a line graph of the limiting oxygen index of the microcapsule-doped chemical fiber spun fibers of the present invention;

[0028] Figure 2 This is a bar chart showing the breaking strength of the microcapsule-doped chemical fiber spun fibers of the present invention.

[0029] Figure 3 This is a plot of the fiber density of the microcapsule-doped chemical fiber spinning fiber of the present invention;

[0030] Figure 4 This is a SEM image of the microcapsule-doped chemical fiber spun fibers of the present invention;

[0031] Figure 5 This is a SEM image of the microcapsule-doped chemical fiber spun fibers of the present invention;

[0032] Figure 6 This is a SEM image of the microcapsule-doped chemical fiber spun fibers of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment discloses a method for preparing a flame-retardant core material, including the following steps:

[0036] S1: Add 15g of chitosan to 1500g of 1wt% acetic acid aqueous solution and stir magnetically for 2h to obtain chitosan solution; add 30g of ammonium polyphosphate to 1480g of water, stir and sonicate for 10min to obtain ammonium polyphosphate solution.

[0037] S2: Dissolve 21g of 2-aminoterephthalic acid and 13g of ZrCl4 in 1200mL of DMF, react at 120℃ for 12h, centrifuge, wash 5 times with methanol, and finally dry under vacuum at 80℃ for 2h to obtain the aminozirconium organic framework.

[0038] S3: The aminozirconium organic framework is immersed in the chitosan solution prepared in S1 for 6 min, the precipitate is washed with water 3 times, and then immersed in the ammonium polyphosphate solution prepared in S1 for 6 min. The precipitate is washed with water 3 times. The assembly process is repeated 4 times to obtain the flame-retardant core material.

[0039] Example 2

[0040] This embodiment discloses a method for preparing flame-retardant microcapsules, including the following steps:

[0041] P1: Add 37g SMA to 1.8L of water, add triethanolamine to adjust the pH to 5.5, then add 15g of the flame-retardant core material prepared in Example 1, first mechanically stir at 800rpm for 10min to pre-disperse, then sonicate for 7min to obtain an aqueous system, and place the aqueous system in a 70℃ water bath.

[0042] P2: Under mechanical stirring at 1500 rpm, 300 mL of MMA, 30 g of EGDMA and 7 g of AIBN were mixed to obtain an oil phase; the oil phase was slowly added dropwise to the aqueous phase, and emulsification was continued for 30 min. The stirring speed was reduced to 700 rpm, and the reaction was continued at 70 °C for 6 h. After cooling to room temperature, the mixture was washed with water by vacuum filtration, washed twice with ethanol, and dried under vacuum at 50 °C for 24 h to obtain flame-retardant microcapsules.

[0043] Example 3

[0044] This embodiment discloses a method for preparing microcapsule-doped chemical fiber spinning fibers, including the following steps:

[0045] Polyester chips were dried at 135°C for 9 hours. Then, 7 parts of the flame-retardant microcapsules prepared in Example 2 were mixed with 143 parts of polyester chips at 500 rpm for 45 minutes. The mixture was then spun using a single-screw melt spinning machine and cooled and solidified under side-blowing conditions at 23°C. The cooled and solidified monofilaments were bundled and oiled with polyester oiling agent, with the oiling rate controlled at 0.6%. After initial drawing in an 80°C hot water bath and final drawing in a 135°C hot roller, the total draw ratio was 4.6, resulting in microcapsule-doped chemical fiber spun fibers.

[0046] Spinning temperature: Zone 1: 265°C; Zone 2: 275°C; Zone 3: 285°C; Chamber temperature: 280°C.

[0047] Polyester oil agent TK-3182A.B was purchased from Nanyang Zhenhua Additives Co., Ltd.

[0048] Example 4

[0049] This embodiment discloses a method for preparing microcapsule-doped chemical fiber spinning fibers, including the following steps:

[0050] Polyester chips were dried at 130°C for 10 hours. Then, 5 parts of the flame-retardant microcapsules prepared in Example 2 were mixed with 190 parts of polyester chips at 400 rpm for 50 minutes. The mixture was then spun using a single-screw melt spinning machine and cooled and solidified under side-blowing conditions at 20°C. The cooled and solidified monofilaments were bundled and oiled with polyester oil, with the oil application rate controlled at 0.7%. After initial drawing in an 80°C hot water bath and final drawing in a 135°C hot roller, the total draw ratio was controlled between 4.5 to obtain microcapsule-doped chemical fiber spun fibers.

[0051] Spinning temperature: Zone 1: 265°C; Zone 2: 275°C; Zone 3: 285°C; Chamber temperature: 280°C.

[0052] Example 5

[0053] This embodiment discloses a method for preparing microcapsule-doped chemical fiber spinning fibers, including the following steps:

[0054] Polyester chips were dried at 140°C for 8 hours. Then, 10 parts of the flame-retardant microcapsules prepared in Example 2 were mixed with 95 parts of polyester chips at 600 rpm for 40 minutes. The mixture was then spun using a single-screw melt spinning machine and cooled and solidified under side-blowing conditions at 25°C. The cooled and solidified monofilaments were bundled and oiled with polyester oil, with the oil application rate controlled at 0.5%. After initial drawing in an 80°C hot water bath and final drawing in a 135°C hot roller, the total draw ratio was controlled between 5.0 to obtain microcapsule-doped chemical fiber spun fibers.

[0055] Spinning temperature: Zone 1: 265°C; Zone 2: 275°C; Zone 3: 285°C; Chamber temperature: 280°C.

[0056] Comparative Example 1

[0057] Compared with Example 3, Comparative Example 1 did not add flame-retardant microcapsules during the preparation of microcapsule-doped chemical fiber spinning, while other conditions remained unchanged.

[0058] Comparative Example 2

[0059] Compared with Example 3, Comparative Example 2 directly added flame-retardant core material as flame retardant during the preparation of microcapsule-doped chemical fiber spinning, without making microcapsules, while other conditions remained unchanged.

[0060] Comparative Example 3

[0061] Compared with Example 3, Comparative Example 3 used ammonium polyphosphate to replace the flame-retardant core material of Example 1 in the process of preparing microcapsule-doped chemical fiber spinning, while keeping other conditions unchanged.

[0062] Comparative Example 4

[0063] Compared with Example 3, Comparative Example 4 used an aminozirconium organic framework to replace the flame-retardant core material of Example 1 in the process of preparing microcapsule-doped chemical fiber spinning, while keeping other conditions unchanged.

[0064] Experimental Example

[0065] The properties of the microcapsule-doped chemical fiber spun fibers prepared in Examples 3-5 and Comparative Examples 1-4 were tested. The limiting oxygen index was tested according to ASTM D2863, the breaking strength according to ASTM D3822, the thermal decomposition temperature and char residue according to ASTM E1131, and the fiber density according to GB / T 1033.2-2010. The test results are shown in Table 1.

[0066] Table 1

[0067] As can be seen from Table 1, the microcapsule-doped chemical fiber spun fibers prepared in Examples 3-5 have good mechanical properties, flame retardancy, and thermal stability. From the comparison between Comparative Examples 1-4 and Example 3, it can be seen that the microcapsule-doped chemical fiber spun fibers prepared by adding the flame-retardant microcapsules of this application in the process of preparing microcapsule-doped chemical fiber spun fibers have good mechanical properties, flame retardancy, and thermal stability. Replacing the flame-retardant core material with ammonium polyphosphate or zirconium aminophosphate organic framework, or not preparing microcapsules, will reduce the performance of the fiber.

[0068] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0069] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing microcapsule-doped chemical fiber spinning fibers, characterized in that, Includes the following steps: Flame-retardant microcapsules are mixed with dried polyester chips, spun using a single-screw melt spinning machine, cooled and solidified, the monofilaments are bundled, oiled, and drawn to obtain microcapsule-doped chemical fiber spun fibers.

2. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 1, characterized in that, The drying conditions are as follows: drying temperature is 130-140℃, drying time is 8-10h; the ratio of flame-retardant microcapsules to polyester chips is 5-10:95-190; mixing method: mixing at 400-600rpm for 40-50min; spinning temperature: zone 1 265℃, zone 2 275℃, zone 3 285℃, and the spinning chamber 280℃; cooling and curing method: cooling and curing under side-blowing conditions at 20-25℃; oiling method: using polyester oiling agent, with the oiling rate controlled at 0.5-0.7%; drawing method: initial drawing in an 80℃ hot water bath and final drawing on a 135℃ hot roller; the total draw ratio is 4.5-5.

0.

3. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 2, characterized in that, The method for preparing the flame-retardant microcapsules includes the following steps: P1: Add SMA to water, add triethanolamine to adjust the pH, then add flame retardant core material, first mechanically stir to pre-disperse, then ultrasonically treat to obtain an aqueous system, and place the aqueous system in a 65-75℃ water bath; P2: Under mechanical stirring, MMA, EGDMA and AIBN were mixed to obtain an oil phase; the oil phase was slowly added dropwise to the aqueous phase to continue emulsification, the stirring speed was reduced, the reaction was continued, cooled to room temperature, washed, and vacuum dried to obtain flame-retardant microcapsules.

4. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 3, characterized in that, In P1, the ratio of SMA, water, and flame-retardant core material is 25-50g:1.2-2.4L:10-20g; the pH value is adjusted to 5.0-5.5; the mechanical stirring pre-dispersion method is: mechanical stirring pre-dispersion at a speed of 600-1000rpm for 8-12min; the ultrasonic treatment time is 5-10min; and the water bath temperature is 65-75℃.

5. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 3, characterized in that, In P2, the mechanical stirring speed is 1300-1700 rpm; the ratio of MMA, EGDMA, and AIBN is 200-400 mL: 20-40 g: 5-10 g; the emulsification time is 25-35 min; the stirring speed is reduced to 600-800 rpm; the reaction is continued at 65-75℃ for 5-7 h; the washing method is to wash with water by vacuum filtration, and then wash with ethanol 1-3 times; the drying method is to vacuum dry at 45-55℃ for 20-28 h.

6. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 3, characterized in that, The method for preparing the flame-retardant core material includes the following steps: S1: Add chitosan to an aqueous acetic acid solution and stir magnetically to obtain a chitosan solution; add ammonium polyphosphate to water, stir and sonicate to obtain an ammonium polyphosphate solution; S2: Dissolve 2-aminoterephthalic acid and ZrCl4 in DMF, react, centrifuge, wash, and finally vacuum dry to obtain an aminozirconium organic framework; S3: The aminozirconium organic framework is immersed in the chitosan solution prepared in S1. The precipitate is washed with water 2-4 times, and then immersed in the ammonium polyphosphate solution prepared in S1. The precipitate is washed with water 2-4 times. The assembly process is repeated 3-5 times to obtain the flame-retardant core material.

7. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 1, characterized in that, In step S1, the ratio of chitosan, aqueous acetic acid solution, ammonium polyphosphate, and water is 10-20g:990-2000g:20-40g:980-1960g; the mass fraction of the aqueous acetic acid solution is 1wt%; the magnetic stirring time is 1.5-2.5h; and the ultrasonic treatment time is 8-12min.

8. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 1, characterized in that, In S2, the ratio of 2-aminoterephthalic acid, ZrCl4, and DMF is 14-28g:12-14g:800-1600mL; the reaction method is to react at 115-125℃ for 10-14h; the washing method is to wash with methanol 4-6 times; and the vacuum drying method is to vacuum dry at 75-85℃ for 1.5-2.5h.

9. The method for preparing microcapsule-doped chemical fiber spinning fibers according to claim 1, characterized in that, In step S3, the soaking time is 5-7 minutes; the immersion time is 5-7 minutes.

10. A microcapsule-doped chemical fiber spun fiber prepared by the method according to any one of claims 1-9.

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