Antibacterial bicomponent polyester staple fiber and method of making same

Abstract

The present application relates to the technical field of polyester fiber material, in particular to an antibacterial bicomponent polyester staple fiber and a preparation method thereof. The present application adopts a skin-core composite spinning process, uses low-melting-point polyester as a skin layer and high-melting-point polyester as a core layer, and obtains a primary filament bundle through melt extrusion, composite spinning and ring blowing air cooling, and then obtains a skin-core bicomponent polyester fiber through oil bath drafting, washing and drying; the bicomponent polyester fiber is subjected to surface antibacterial modification, cutting and packaging to obtain the antibacterial bicomponent polyester staple fiber. In the present application, the surface antibacterial modification adopts ultraviolet light to initiate an acrylamide and 3-methyl acrylamide dopamine system for preliminary modification on the surface of the polyester fiber, and then cross-linking is performed through an epoxy-based hydrazine and a chitosan quaternary ammonium salt to construct a stable antibacterial layer on the surface of the polyester fiber, so that a long-acting antibacterial effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of polyester fiber material technology, specifically to an antibacterial bicomponent polyester staple fiber and its preparation method. Background Technology

[0002] Polyester fiber (polyester) is widely used in clothing, home textiles, bedding, filling materials, and industrial protective equipment due to its outstanding advantages such as high strength, wrinkle resistance, shape retention, and durability. It is one of the most produced synthetic fiber varieties. Ordinary polyester fiber has a dense molecular structure and lacks hydrophilic groups, making the material itself highly hydrophobic, with poor moisture absorption and breathability, resulting in poor comfort when used.

[0003] Existing research on bicomponent polyester fibers largely focuses on controlling fiber cross-sectional morphology and optimizing crimp and bulk properties, primarily addressing moisture absorption and wicking issues. The fiber itself lacks antibacterial and antifungal properties, leaving a shortcoming of microbial growth in high-humidity, sweaty environments. Chinese patent application CN202310977176.1 discloses the use of natural plant extracts such as grapefruit leaves, tea leaves, and bamboo leaves to modify polyester mattress materials. This utilizes the polyphenols and flavonoids within the plants to impart antibacterial and moisture-absorbing properties, combined with a chitosan quaternary ammonium salt-graphene oxide compound treatment solution to further enhance antibacterial effects and functional durability. While natural plant-derived modification offers advantages such as non-toxicity, environmental friendliness, and recyclability, the extraction process for plant active substances is cumbersome. Therefore, it is essential to provide an antibacterial bicomponent polyester staple fiber with excellent antibacterial and antifungal properties. Summary of the Invention

[0004] The purpose of this invention is to provide an antibacterial bicomponent polyester staple fiber and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing antibacterial bicomponent polyester staple fiber, comprising the following steps: Step 1: Using a core-sheath composite spinning process, low-melting-point polyester is used as the sheath and high-melting-point polyester as the core. The dried low-melting-point polyester chips and high-melting-point polyester chips are fed into two independent extruders for melting, and then fed into the composite spinning assembly. After extrusion, the chips are cooled and solidified by two ring blowers, and then wound and collected to obtain the nascent filament bundle. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

[0006] Furthermore, in step 1, the melting point of the low-melting-point polyester is 215~235℃, and the melting point of the high-melting-point polyester is 250~255℃.

[0007] Furthermore, in step 1, the process parameters for the two-stage annular air blowing cooling are as follows: the temperature of the first annular air blowing stage is 50~70℃, and the air velocity is 1.0~3.0m / s; the temperature of the second annular air blowing stage is 10~20℃, and the air velocity is 2.0~4.0m / s; the interval between the two cooling annular air blowing stages is 35~50cm. Furthermore, in step 2, during the oil bath stretching treatment, the oil bath temperature is 65~75℃, and the stretching ratio is 2.4~3.0 times.

[0008] Furthermore, in step 2, the monofilament fineness of the bicomponent polyester fiber with a core-sheath structure is 2.0~4.0 dtex, the breaking strength is ≥3.10 cN / dtex, and the core-sheath area ratio is (40~60):(60~40).

[0009] Furthermore, in step 2, the surface antibacterial modification treatment method includes the following steps: S1: Acrylamide, 3-methacrylamide, N,N-methylenebisacrylamide, and photoinitiator are dispersed in 80% ethanol / water solution to obtain a mixed monomer solution; bicomponent polyester fibers are immersed in the mixed monomer solution and photoinitiated using an ultraviolet light generator. After the reaction is completed, the bicomponent polyester fibers are removed, washed, and dried to obtain modified bicomponent polyester fibers. S2: Disperse 5,5-dimethylhydantoin in water, add NaOH solution to adjust the pH to 8-9, add epichlorohydrin to react, after the reaction is complete, remove the solvent water by rotary evaporation, dissolve the obtained product in acetone, filter to remove impurities, remove the solvent acetone by rotary evaporation, and obtain epoxy hydantoin. S3: Add chitosan quaternary ammonium salt to water to obtain chitosan quaternary ammonium salt solution; immerse modified bicomponent polyester fiber in chitosan quaternary ammonium salt solution for 12 hours, remove and wash with water, dry, then transfer modified bicomponent polyester fiber to epoxy hydantoin / water solution; adjust pH to 5-6 with dilute hydrochloric acid, react at 50-60℃ for 24 hours, wash with water and vacuum dry to obtain antibacterial bicomponent polyester fiber.

[0010] Furthermore, in S1, the concentration of acrylamide in the mixed monomer solution is 1~1.2 mol / L; the mass ratio of acrylamide, 3-methacrylamide and N,N-methylenebisacrylamide is (70~80):(20~30):(1~1.5).

[0011] Furthermore, in S2, the molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1.

[0012] Furthermore, in S3, the degree of substitution of chitosan quaternary ammonium salt is 40%~60%.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention employs a core-sheath composite spinning process, using low-melting-point polyester as the sheath layer and high-melting-point polyester as the core layer to produce bicomponent polyester staple fibers with a core-sheath structure. These bicomponent polyester staple fibers exhibit high mechanical strength, a uniform and stable structure, and can withstand subsequent textile processing steps such as cutting, opening, and spinning. They are less prone to breakage and shedding, and have good processing adaptability.

[0014] Traditional polyester fibers have few surface-active groups and are chemically inert, making it difficult to stably adhere antibacterial agents to the fiber surface using conventional coating or immersion methods. The antibacterial agent also detaches after washing, reducing the antibacterial effect. This invention uses 3-methacryloyldopamine as the active monomer, which is photo-initiated and copolymerized with acrylamide to form a gel layer on the polyester fiber surface, achieving preliminary modification. The 3-methacryloyldopamine in the gel layer possesses catechol functional groups, which strongly adsorb onto the polyester fiber surface through hydrogen bonding and π-π interactions; it also provides a strong binding anchor for subsequent loading of antibacterial components, thereby enhancing the adhesion between the antibacterial layer and the fiber matrix.

[0015] This invention uses small-molecule epoxy hydantoin as a bridging component and selects chitosan quaternary ammonium salt with a substitution degree of 40%~60% as the main antibacterial active component. At this substitution degree, the chitosan quaternary ammonium salt contains a large amount of quaternary ammonium cations, possessing inherent antibacterial activity, while the molecular chain retains a sufficient amount of unreacted primary amino groups. Under weakly acidic and mild conditions, the primary amino groups can covalently open the ring with the epoxy groups of epoxy hydantoin and undergo a cross-linking reaction. The cross-linking reaction includes two aspects: on the one hand, the amino groups in the chitosan quaternary ammonium salt molecules cross-link with each other, and after cross-linking, the chitosan quaternary ammonium salt forms an antibacterial layer, while its water solubility decreases, making it difficult to dissolve in water during washing; on the other hand, in the presence of epoxy groups, the amino groups of 3-methacryloyldopamine and acrylamide in the gel layer also react with the amino groups in the chitosan quaternary ammonium salt molecules, so that the chemical bonds and physical hydrogen bonds between them work together to improve the bonding force between the antibacterial layer and the gel layer on the surface of the polyester fiber, thereby overcoming the problems of easy removal and short-lasting antibacterial effect of traditional antibacterial agents after washing. In addition, the cationic antibacterial effect of chitosan quaternary ammonium salt and the antibacterial effect of hydantoin derivatives work synergistically to endow polyester fibers with broad-spectrum antibacterial ability and have a good inhibitory effect on bacteria and other microorganisms.

[0016] The present invention features mild modification conditions, simple process operation, and easy industrial scale-up. The prepared antibacterial bicomponent polyester staple fiber can be applied to a variety of fields such as antibacterial home textiles, filter materials, and sanitary textiles. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Materials used in this invention and their sources: Low melting point polyester chips (melting point 220℃, PET) and high melting point polyester chips (melting point 255℃, PET) were purchased from Yizheng Xiangheng Polyester Technology Co., Ltd.; Chitosan quaternary ammonium salt (degree of substitution 40%) was purchased from Xi'an Qiyue Biotechnology Co., Ltd.; Chitosan quaternary ammonium salt (degree of substitution 90%) was purchased from Shanghai Beyotime Biotechnology Co., Ltd.

[0019] Example 1: A method for preparing antibacterial bicomponent polyester staple fiber, comprising the following steps: Step 1: Vacuum dry low-melting-point polyester chips and high-melting-point polyester chips for 24 hours, then set aside. Using a core-sheath composite spinning process, with low-melting-point polyester as the sheath and high-melting-point polyester as the core, feed the dried low-melting-point and high-melting-point polyester chips into two independent extruders for melting, then combine them into a composite spinning assembly. After extrusion, the sheath spinning temperature is 255℃, and the core spinning temperature is 280℃. After two stages of ring-blowing cooling and solidification, the first ring-blowing temperature is 50℃ with a wind speed of 1.0 m / s; the second ring-blowing temperature is 10℃ with a wind speed of 2.0 m / s. The two cooling ring-blowing stages are spaced 35 cm apart. The resulting nascent filament bundles are then wound and collected. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; the oil bath temperature is 65℃, and the stretching ratio is 2.4 times; the monofilament fineness of the bicomponent polyester fibers is 2.0 dtex, and the breaking strength is ≥3.10 cN / dtex; the core-sheath area ratio of the core-sheath structure is 40:60; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

[0020] The steps for antibacterial modification treatment of bicomponent polyester fiber surface are as follows: S1: Acrylamide, 3-methacrylamide, N,N-methylenebisacrylamide, and photoinitiator were dispersed in 80% (V / V) ethanol / water solution to obtain a mixed monomer solution; the bicomponent polyester fiber was immersed in the mixed monomer solution for 1 hour at a bath ratio of 1:50, and a photoinitiation reaction was carried out for 30 minutes using a 440W ultraviolet light generator. After the reaction was completed, the bicomponent polyester fiber was taken out, washed with acetone, and then immersed in water for 6 hours to remove unreacted monomers. The dried product was then used to obtain modified bicomponent polyester fiber. In the mixed monomer solution, the concentration of acrylamide is 1 mol / L; the mass ratio of acrylamide, 3-methacrylamide, and N,N-methylenebisacrylamide is 70:30:1. S2: Disperse 5,5-dimethylhydantoin in water, add NaOH solution to adjust the pH to 8, add epichlorohydrin and react for 8 hours. After the reaction is complete, remove the solvent water by rotary evaporation, dissolve the obtained product in acetone, filter to remove insoluble sodium chloride impurities, and remove the solvent acetone by rotary evaporation to obtain epoxy hydantoin; wherein, the molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1; S3: Add chitosan quaternary ammonium salt to water and stir to dissolve to obtain a chitosan quaternary ammonium salt solution with a mass concentration of 1 wt.%; immerse the modified bicomponent polyester fiber in the chitosan quaternary ammonium salt solution at a bath ratio of 1:50 for 12 hours, remove and wash with water, dry, then transfer the modified bicomponent polyester fiber to a 1 wt.% epoxy hydantoin / water solution at a bath ratio of 1:50; adjust the pH value to 5 with dilute hydrochloric acid, react at 50℃ for 24 hours, remove and wash with water 3 times, vacuum dry to obtain antibacterial bicomponent polyester fiber.

[0021] Example 2: A method for preparing antibacterial bicomponent polyester staple fiber, comprising the following steps: Step 1: Vacuum dry low-melting-point polyester chips and high-melting-point polyester chips for 24 hours and set aside. Using a core-sheath composite spinning process, with low-melting-point polyester as the sheath and high-melting-point polyester as the core, feed the dried low-melting-point polyester chips and high-melting-point polyester chips into two independent extruders for melting, then combine them into a composite spinning assembly. After extrusion, the sheath spinning temperature is 255℃ and the core spinning temperature is 280℃. After two stages of ring-blowing cooling and solidification, the first ring-blowing temperature is 60℃ and the ring-blowing velocity is 2.0 m / s; the second ring-blowing temperature is 15℃ and the ring-blowing velocity is 3 m / s. The interval between the two cooling ring-blowing stages is 45 cm. The resulting nascent filament bundles are then wound and collected. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; the oil bath temperature is 70℃, and the stretching ratio is 2.8 times; the monofilament fineness of the bicomponent polyester fibers is 3.0 dtex, and the breaking strength is ≥3.10 cN / dtex; the core-sheath area ratio of the core-sheath structure is 50:50; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

[0022] The steps for antibacterial modification treatment of bicomponent polyester fiber surface are as follows: S1: Acrylamide, 3-methacrylamide, N,N-methylenebisacrylamide, and photoinitiator were dispersed in 80% (V / V) ethanol / water solution to obtain a mixed monomer solution; the bicomponent polyester fiber was immersed in the mixed monomer solution for 1 hour at a bath ratio of 1:50, and a photoinitiation reaction was carried out for 30 minutes using a 440W ultraviolet light generator. After the reaction was completed, the bicomponent polyester fiber was taken out, washed with acetone, and then immersed in water for 6 hours to remove unreacted monomers. The dried product was then used to obtain modified bicomponent polyester fiber. In the mixed monomer solution, the acrylamide concentration was 1.1 mol / L; the mass ratio of acrylamide, 3-methacrylamide, and N,N-methylenebisacrylamide was 75:25:1.2. S2: Disperse 5,5-dimethylhydantoin in water, add NaOH solution to adjust the pH to 8.5, add epichlorohydrin and react for 9.5 h. After the reaction is complete, remove the solvent water by rotary evaporation, dissolve the obtained product in acetone, filter to remove insoluble sodium chloride impurities, and remove the solvent acetone by rotary evaporation to obtain epoxy hydantoin; wherein, the molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1; S3: Add chitosan quaternary ammonium salt to water and stir to dissolve to obtain a chitosan quaternary ammonium salt solution with a mass concentration of 1 wt.%; immerse the modified bicomponent polyester fiber in the chitosan quaternary ammonium salt solution at a bath ratio of 1:50 for 12 hours, remove and wash with water, dry, then transfer the modified bicomponent polyester fiber to a 1.5 wt.% epoxy hydantoin / water solution at a bath ratio of 1:50; adjust the pH value to 5.5 with dilute hydrochloric acid, react at 55℃ for 24 hours, remove and wash with water 3 times, and vacuum dry to obtain antibacterial bicomponent polyester fiber.

[0023] Example 3: A method for preparing antibacterial bicomponent polyester staple fiber, comprising the following steps: Step 1: Vacuum dry low-melting-point polyester chips and high-melting-point polyester chips for 24 hours and set aside. Using a core-sheath composite spinning process, with low-melting-point polyester as the sheath and high-melting-point polyester as the core, feed the dried low-melting-point polyester chips and high-melting-point polyester chips into two independent extruders for melting, then combine them into a composite spinning assembly. After extrusion, the sheath spinning temperature is 255℃ and the core spinning temperature is 280℃. After two stages of ring-blowing cooling and solidification, the first ring-blowing temperature is 70℃ and the ring-blowing velocity is 3.0 m / s; the second ring-blowing temperature is 20℃ and the ring-blowing velocity is 4.0 m / s. The two cooling ring-blowing stages are spaced 50 cm apart. The resulting nascent filament bundles are then wound and collected. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; the oil bath temperature is 75℃, and the stretching ratio is 3.0 times; the monofilament fineness of the bicomponent polyester fibers is 4.0 dtex, and the breaking strength is ≥3.10 cN / dtex; the core-sheath area ratio of the core-sheath structure is 60:40; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

[0024] The steps for antibacterial modification treatment of bicomponent polyester fiber surface are as follows: S1: Acrylamide, 3-methacrylamide, N,N-methylenebisacrylamide, and photoinitiator were dispersed in 80% (V / V) ethanol / water solution to obtain a mixed monomer solution; the bicomponent polyester fiber was immersed in the mixed monomer solution for 1 hour at a bath ratio of 1:50, and a photoinitiation reaction was carried out for 30 minutes using a 440W ultraviolet light generator. After the reaction was completed, the bicomponent polyester fiber was taken out, washed with acetone, and then immersed in water for 6 hours to remove unreacted monomers. The dried product was then used to obtain modified bicomponent polyester fiber. In the mixed monomer solution, the acrylamide concentration was 1.2 mol / L; the mass ratio of acrylamide, 3-methacrylamide, and N,N-methylenebisacrylamide was 80:20:1.5. S2: Disperse 5,5-dimethylhydantoin in water, add NaOH solution to adjust the pH to 9, add epichlorohydrin and react for 10 hours. After the reaction is complete, remove the solvent water by rotary evaporation, dissolve the obtained product in acetone, filter to remove insoluble sodium chloride impurities, and remove the solvent acetone by rotary evaporation to obtain epoxy hydantoin; wherein, the molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1; S3: Add chitosan quaternary ammonium salt to water and stir to dissolve to obtain a chitosan quaternary ammonium salt solution with a mass concentration of 1 wt.%; immerse the modified bicomponent polyester fiber in the chitosan quaternary ammonium salt solution at a bath ratio of 1:50 for 12 hours, remove and wash with water, dry, then transfer the modified bicomponent polyester fiber to a 2 wt.% epoxy hydantoin / water solution at a bath ratio of 1:50; adjust the pH value to 6 with dilute hydrochloric acid, react at 60℃ for 24 hours, remove and wash with water 3 times, vacuum dry to obtain antibacterial bicomponent polyester fiber.

[0025] Comparative Example 1: No surface antibacterial modification treatment was performed in step 2, and the remaining steps were the same as in Example 1.

[0026] Step 1: Vacuum dry low-melting-point polyester chips and high-melting-point polyester chips for 24 hours, then set aside. Using a core-sheath composite spinning process, with low-melting-point polyester as the sheath and high-melting-point polyester as the core, feed the dried low-melting-point and high-melting-point polyester chips into two independent extruders for melting, then combine them into a composite spinning assembly. After extrusion, the sheath spinning temperature is 255℃, and the core spinning temperature is 280℃. After two stages of ring-blowing cooling and solidification, the first ring-blowing temperature is 50℃ with a wind speed of 1.0 m / s; the second ring-blowing temperature is 10℃ with a wind speed of 2.0 m / s. The two cooling ring-blowing stages are spaced 35 cm apart. The resulting nascent filament bundles are then wound and collected. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; the oil bath temperature is 65℃, and the stretching ratio is 2.4 times; the monofilament fineness of the bicomponent polyester fibers is 2.0 dtex, and the breaking strength is ≥3.10 cN / dtex; the core-sheath area ratio of the core-sheath structure is 40:60; the bicomponent polyester fibers are cut and packaged to obtain bicomponent polyester staple fibers.

[0027] Comparative Example 2: In S2, 3-methylacrylamide was not added to the mixed monomer solution, and the remaining steps were the same as in Example 2.

[0028] Step 1: Vacuum dry low-melting-point polyester chips and high-melting-point polyester chips for 24 hours and set aside. Using a core-sheath composite spinning process, with low-melting-point polyester as the sheath and high-melting-point polyester as the core, feed the dried low-melting-point polyester chips and high-melting-point polyester chips into two independent extruders for melting, then combine them into a composite spinning assembly. After extrusion, the sheath spinning temperature is 255℃ and the core spinning temperature is 280℃. After two stages of ring-blowing cooling and solidification, the first ring-blowing temperature is 60℃ and the ring-blowing velocity is 2.0 m / s; the second ring-blowing temperature is 15℃ and the ring-blowing velocity is 3 m / s. The interval between the two cooling ring-blowing stages is 45 cm. The resulting nascent filament bundles are then wound and collected. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; the oil bath temperature is 70℃, and the stretching ratio is 2.8 times; the monofilament fineness of the bicomponent polyester fibers is 3.0 dtex, and the breaking strength is ≥3.10 cN / dtex; the core-sheath area ratio of the core-sheath structure is 50:50; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

[0029] The steps for antibacterial modification treatment of bicomponent polyester fiber surface are as follows: S1: Acrylamide, N,N-methylenebisacrylamide, and photoinitiator were dispersed in 80% (V / V) ethanol / water solution to obtain a mixed monomer solution; bicomponent polyester fibers were immersed in the mixed monomer solution for 1 hour at a bath ratio of 1:50, and a photoinitiation reaction was carried out for 30 minutes using a 440W ultraviolet light generator. After the reaction was completed, the bicomponent polyester fibers were taken out, washed with acetone, and then immersed in water for 6 hours to remove unreacted monomers. The dried fibers were then used to obtain modified bicomponent polyester fibers. In the mixed monomer solution, the acrylamide concentration was 1.1 mol / L; the mass ratio of acrylamide to N,N-methylenebisacrylamide was 100:1.2. S2: Disperse 5,5-dimethylhydantoin in water, add NaOH solution to adjust the pH to 8.5, add epichlorohydrin and react for 9.5 h. After the reaction is complete, remove the solvent water by rotary evaporation, dissolve the obtained product in acetone, filter to remove insoluble sodium chloride impurities, and remove the solvent acetone by rotary evaporation to obtain epoxy hydantoin; wherein, the molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1; S3: Add chitosan quaternary ammonium salt to water and stir to dissolve to obtain a chitosan quaternary ammonium salt solution with a mass concentration of 1 wt.%; immerse the modified bicomponent polyester fiber in the chitosan quaternary ammonium salt solution at a bath ratio of 1:50 for 12 hours, remove and wash with water, dry, then transfer the modified bicomponent polyester fiber to a 1.5 wt.% epoxy hydantoin / water solution at a bath ratio of 1:50; adjust the pH value to 5.5 with dilute hydrochloric acid, react at 55℃ for 24 hours, remove and wash with water 3 times, and vacuum dry to obtain antibacterial bicomponent polyester fiber.

[0030] Comparative Example 3: Hydantoin was used instead of epoxy-based hydantoin, and the remaining steps were the same as in Example 3.

[0031] Step 1: Vacuum dry low-melting-point polyester chips and high-melting-point polyester chips for 24 hours and set aside. Using a core-sheath composite spinning process, with low-melting-point polyester as the sheath and high-melting-point polyester as the core, feed the dried low-melting-point polyester chips and high-melting-point polyester chips into two independent extruders for melting, then combine them into a composite spinning assembly. After extrusion, the sheath spinning temperature is 255℃ and the core spinning temperature is 280℃. After two stages of ring-blowing cooling and solidification, the first ring-blowing temperature is 70℃ and the ring-blowing velocity is 3.0 m / s; the second ring-blowing temperature is 20℃ and the ring-blowing velocity is 4.0 m / s. The two cooling ring-blowing stages are spaced 50 cm apart. The resulting nascent filament bundles are then wound and collected. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; the oil bath temperature is 75℃, and the stretching ratio is 3.0 times; the monofilament fineness of the bicomponent polyester fibers is 4.0 dtex, and the breaking strength is ≥3.10 cN / dtex; the core-sheath area ratio of the core-sheath structure is 60:40; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

[0032] The steps for antibacterial modification treatment of bicomponent polyester fiber surface are as follows: S1: Acrylamide, 3-methacrylamide, N,N-methylenebisacrylamide, and photoinitiator were dispersed in 80% (V / V) ethanol / water solution to obtain a mixed monomer solution; the bicomponent polyester fiber was immersed in the mixed monomer solution for 1 hour at a bath ratio of 1:50, and a photoinitiation reaction was carried out for 30 minutes using a 440W ultraviolet light generator. After the reaction was completed, the bicomponent polyester fiber was taken out, washed with acetone, and then immersed in water for 6 hours to remove unreacted monomers. The dried product was then used to obtain modified bicomponent polyester fiber. In the mixed monomer solution, the acrylamide concentration was 1.2 mol / L; the mass ratio of acrylamide, 3-methacrylamide, and N,N-methylenebisacrylamide was 80:20:1.5. S2: Add chitosan quaternary ammonium salt to water and stir to dissolve to obtain a chitosan quaternary ammonium salt solution with a mass concentration of 1 wt.%; immerse the modified bicomponent polyester fiber in the chitosan quaternary ammonium salt solution at a bath ratio of 1:50 for 12 hours, remove and wash with water, dry, then transfer the modified bicomponent polyester fiber to a 2 wt.% hydantoin / water solution at a bath ratio of 1:50; adjust the pH value to 6 with dilute hydrochloric acid, react at 60℃ for 24 hours, remove and wash with water 3 times, vacuum dry to obtain antibacterial bicomponent polyester fiber.

[0033] Comparative Example 4: A highly substituted chitosan quaternary ammonium salt (90% substitution degree) was used to replace the chitosan quaternary ammonium salt in Example 3, and the remaining parameters were the same as in Example 3.

[0034] Step 1: Vacuum dry low-melting-point polyester chips and high-melting-point polyester chips for 24 hours and set aside. Using a core-sheath composite spinning process, with low-melting-point polyester as the sheath and high-melting-point polyester as the core, feed the dried low-melting-point polyester chips and high-melting-point polyester chips into two independent extruders for melting, then combine them into a composite spinning assembly. After extrusion, the sheath spinning temperature is 255℃ and the core spinning temperature is 280℃. After two stages of ring-blowing cooling and solidification, the first ring-blowing temperature is 70℃ and the ring-blowing velocity is 3.0 m / s; the second ring-blowing temperature is 20℃ and the ring-blowing velocity is 4.0 m / s. The two cooling ring-blowing stages are spaced 50 cm apart. The resulting nascent filament bundles are then wound and collected. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; the oil bath temperature is 75℃, and the stretching ratio is 3.0 times; the monofilament fineness of the bicomponent polyester fibers is 4.0 dtex, and the breaking strength is ≥3.10 cN / dtex; the core-sheath area ratio of the core-sheath structure is 60:40; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

[0035] The steps for antibacterial modification treatment of bicomponent polyester fiber surface are as follows: S1: Acrylamide, 3-methacrylamide, N,N-methylenebisacrylamide, and photoinitiator were dispersed in 80% (V / V) ethanol / water solution to obtain a mixed monomer solution; the bicomponent polyester fiber was immersed in the mixed monomer solution for 1 hour at a bath ratio of 1:50, and a photoinitiation reaction was carried out for 30 minutes using a 440W ultraviolet light generator. After the reaction was completed, the bicomponent polyester fiber was taken out, washed with acetone, and then immersed in water for 6 hours to remove unreacted monomers. The dried product was then used to obtain modified bicomponent polyester fiber. In the mixed monomer solution, the acrylamide concentration was 1.2 mol / L; the mass ratio of acrylamide, 3-methacrylamide, and N,N-methylenebisacrylamide was 80:20:1.5. S2: Disperse 5,5-dimethylhydantoin in water, add NaOH solution to adjust the pH to 9, add epichlorohydrin and react for 10 hours. After the reaction is complete, remove the solvent water by rotary evaporation, dissolve the obtained product in acetone, filter to remove insoluble sodium chloride impurities, and remove the solvent acetone by rotary evaporation to obtain epoxy hydantoin; wherein, the molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1; S3: Add chitosan quaternary ammonium salt to water and stir to dissolve to obtain a chitosan quaternary ammonium salt solution with a mass concentration of 1 wt.%; immerse the modified bicomponent polyester fiber in the chitosan quaternary ammonium salt solution at a bath ratio of 1:50 for 12 hours, remove and wash with water, dry, then transfer the modified bicomponent polyester fiber to a 2 wt.% epoxy hydantoin / water solution at a bath ratio of 1:50; adjust the pH value to 6 with dilute hydrochloric acid, react at 60℃ for 24 hours, remove and wash with water 3 times, vacuum dry to obtain antibacterial bicomponent polyester fiber.

[0036] Experiment: The polyester staple fibers from Examples 1-3 and Comparative Examples 1-4 were spun to produce fabrics. The antibacterial properties (Escherichia coli, Staphylococcus aureus, Candida albicans) of the fabrics were tested according to GB / T20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Vibration method". To further investigate the stability of the antibacterial properties, the samples were washed 10 times using the "10.1.1 Wash fastness test machine washing method" in the above standard, and then the fabrics were tested for antibacterial properties (wash fastness antibacterial stability). The experimental results are shown in Table 1.

[0037] Table 1.

[0038] Conclusion: The data from Example 1 and Comparative Example 1 show that the bicomponent polyester staple fiber prepared by the technical solution of this application has good antibacterial properties. In Example 2, because the mixed monomer solution contains 3-methacrylamide, the gel layer formed after UV-initiated polymerization has good adhesion properties. Therefore, the sample still has good antibacterial properties after multiple washes. However, in Comparative Example 2, because 3-methacrylamide was not added, the gel layer formed after UV-initiated polymerization had poor adhesion properties and fell off after washing, thus leading to a decrease in antibacterial properties. In Example 3, epoxy-based hydantoin was used, which can react with the active primary amino groups in chitosan quaternary ammonium salt to form an antibacterial layer through chemical cross-linking. After multiple washes, the antibacterial layer was stably attached to the fiber surface and had strong water resistance. However, in Comparative Example 3, the hydantoin was not epoxy-modified and could not achieve chemical cross-linking of chitosan quaternary ammonium salt. Chitosan quaternary ammonium salt is highly water-soluble and dissolves in water after multiple washes, thus reducing the antibacterial properties. In Comparative Example 4, a chitosan quaternary ammonium salt with a higher degree of substitution was used. Its molecule contains fewer amino groups that can react with epoxy groups, and cross-linking hardly occurs. Therefore, the antibacterial properties of the polyester fiber are significantly reduced after multiple washes.

[0039] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing antibacterial bicomponent polyester staple fiber, comprising the following steps: Step 1: Using a core-sheath composite spinning process, low-melting-point polyester is used as the sheath and high-melting-point polyester as the core. The dried low-melting-point polyester chips and high-melting-point polyester chips are fed into two independent extruders for melting, and then fed into the composite spinning assembly. After extrusion, the chips are cooled and solidified by two ring blowers, and then wound and collected to obtain the nascent filament bundle. Step 2: The nascent filament bundles are subjected to oil bath stretching, washing, and drying to obtain bicomponent polyester fibers with a core-sheath structure; after surface antibacterial modification treatment, the bicomponent polyester fibers are cut and packaged to obtain antibacterial bicomponent polyester staple fibers.

2. The preparation method according to claim 1, characterized in that: In step 1, the melting point of low-melting-point polyester is 215~235℃, and the melting point of high-melting-point polyester is 250~255℃.

3. The preparation method according to claim 1, characterized in that: In step 1, the process parameters for the two-stage ring-blowing cooling system are as follows: the temperature of the first ring-blowing air is 50~70℃, and the air velocity is 1.0~3.0m / s; the temperature of the second ring-blowing air is 10~20℃, and the air velocity is 2.0~4.0m / s; the interval between the two cooling ring-blowing air stages is 35~50cm.

4. The preparation method according to claim 1, characterized in that: In step 2, during the oil bath stretching treatment, the oil bath temperature is 65~75℃ and the stretching ratio is 2.4~3.0 times.

5. The preparation method according to claim 1, characterized in that: In step 2, the monofilament fineness of the bicomponent polyester fiber with a core-sheath structure is 2.0~4.0 dtex, the breaking strength is ≥3.10 cN / dtex, and the core-sheath area ratio is (40~60):(60~40).

6. The preparation method according to claim 1, characterized in that: Step 2, the surface antibacterial modification treatment method, includes the following steps: S1: Acrylamide, 3-methacrylamide, N,N-methylenebisacrylamide, and photoinitiator are dispersed in 80% ethanol / water solution to obtain a mixed monomer solution; bicomponent polyester fibers are immersed in the mixed monomer solution and photoinitiated using an ultraviolet light generator. After the reaction is completed, the bicomponent polyester fibers are removed, washed, and dried to obtain modified bicomponent polyester fibers. S2: 5,5-Dimethylhydantoin is reacted with epichlorohydrin to obtain epoxyhydantoin; S3: Add chitosan quaternary ammonium salt to water to obtain chitosan quaternary ammonium salt solution; immerse modified bicomponent polyester fiber in chitosan quaternary ammonium salt solution for 12 hours, remove and wash with water, dry, transfer modified bicomponent polyester fiber to epoxy hydantoin / water solution for 24 hours, wash with water and vacuum dry to obtain antibacterial bicomponent polyester fiber.

7. The preparation method according to claim 6, characterized in that: In S1, the concentration of acrylamide in the mixed monomer solution is 1~1.2 mol / L; the mass ratio of acrylamide, 3-methylacrylamide and N,N-methylenebisacrylamide is (70~80):(20~30):(1~1.5).

8. The preparation method according to claim 6, characterized in that: In S2, the molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:

1.

9. The preparation method according to claim 6, characterized in that: In S3, the degree of substitution of chitosan quaternary ammonium salt is 40%~60%.

10. Antibacterial bicomponent polyester staple fibers prepared by the method according to any one of claims 1 to 9.

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