An antibacterial and environmentally friendly masterbatch dyeing fiber and its preparation method

Abstract

This invention discloses an antibacterial and environmentally friendly masterbatch-dyed fiber and its preparation method, relating to the field of fiber preparation technology. The method includes: S1: Preparing an antibacterial agent: Selecting a GRAS-certified antibacterial pigment-producing strain and performing liquid deep fermentation to obtain antibacterial pigment powder; S2: Preparing a reinforcing masterbatch: Mixing the obtained antibacterial pigment powder with a polymer carrier resin and natural seaweed fiber in a specific ratio and granulating to obtain an antibacterial reinforcing masterbatch; S3: Fiber spinning and forming: Mixing the obtained antibacterial reinforcing masterbatch with a matrix resin and processing it to obtain an antibacterial and environmentally friendly masterbatch-dyed reinforced fiber; S4: Reinforcing weaving: Reinforcing weaving the obtained antibacterial and environmentally friendly masterbatch-dyed reinforced fiber to form a composite fiber. This invention, by using GRAS-certified microbial fermentation to produce antibacterial pigments, ensures the biosafety and environmental friendliness of the product, and improves the antibacterial and degradation properties of the fiber.

Description

Technical Field

[0001] This invention relates to the field of fiber preparation technology, and in particular to an antibacterial and environmentally friendly masterbatch dyeing fiber and its preparation method. Background Technology

[0002] With the increasing awareness of environmental protection and the pursuit of a healthy quality of life, textile materials that combine environmental protection and antibacterial functions have become a research hotspot. Existing traditional antibacterial textiles are mainly achieved through finishing methods, that is, antibacterial agents such as silver ions and organic antibacterial agents are attached to the surface of fibers or fabrics through impregnation, coating and other methods.

[0003] Currently, most widely used antibacterial agents are chemically synthesized or metal ion-based, and their biosafety and environmental friendliness are often questioned. When used through methods such as impregnation and coating, their antibacterial durability is poor. After repeated washing, the antibacterial agent is easy to fall off and is difficult to maintain its activity in high-temperature melt spinning, resulting in a sharp reduction in antibacterial effect. Some chemically synthesized antibacterial agents may irritate the skin and may also cause secondary pollution to the environment after disposal, affecting the antibacterial and degradation properties of fibers. Summary of the Invention

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

[0005] To achieve the above objectives, the present invention provides the following technical solution: an antibacterial and environmentally friendly masterbatch dyeing fiber, specifically comprising the following steps:

[0006] S1: Preparation of antibacterial agent: Select antibacterial pigment producing strains that have been certified by GRAS, inoculate them into fermentation medium for liquid deep fermentation, and then separate, extract, purify and dry the fermentation broth to obtain antibacterial pigment powder;

[0007] S2: Preparation of enhanced masterbatch: The antibacterial pigment powder obtained above is mixed with polymer carrier resin, natural seaweed fiber, dispersant, stabilizer and reinforcing agent in proportion, and then melt-blended and extruded to granulate to obtain antibacterial enhanced masterbatch;

[0008] S3: Fiber spinning and forming: The antibacterial reinforced masterbatch obtained above is mixed with the matrix resin, and after pretreatment, melt spinning, stretching and winding, antibacterial and environmentally friendly masterbatch dyeing reinforced fiber is obtained.

[0009] S4: Reinforced weaving: The antibacterial and environmentally friendly masterbatch dyed and reinforced fibers obtained above are subjected to reinforced weaving treatment to form composite fibers.

[0010] Preferably, the GRAS-certified antimicrobial pigment-producing strain in step S1 is one or more of Micrococcus luteus, Rhodotorula glutinis, or Penicillium purpureum, and the pigment yield of the strain is not less than 1.2 g / L. The antimicrobial pigment is used to inhibit the activity of Escherichia coli and Staphylococcus aureus.

[0011] Preferably, the fermentation medium in step S1 includes a carbon source, a nitrogen source, inorganic salts, and a metabolism promoter; wherein the carbon source is glucose, the nitrogen source is yeast extract and peptone, and the inorganic salts include potassium dihydrogen phosphate, magnesium sulfate, and ferrous sulfate; the medium also contains Tween-80 and L-tyrosine.

[0012] Preferably, the process conditions for the liquid submerged fermentation in step S1 are as follows:

[0013] The inoculum size is controlled at 4-6%, the seed culture concentration is controlled at the logarithmic growth phase of the cells, a neutral pH environment is maintained during fermentation, dissolved oxygen is controlled by stirring and aeration, the fermentation cycle is controlled at 48-72 hours, and a carbon source is added in the middle of fermentation.

[0014] Preferably, the natural seaweed fiber in step S2 is one or more of brown algae fiber, kelp fiber, or laver fiber, and is used after pretreatment with alkali solution; the mass fraction of the natural seaweed fiber in the antibacterial enhancing masterbatch is 3-8%.

[0015] Preferably, the natural seaweed fiber pretreatment process in step S2 is as follows: the natural seaweed fiber is cut into short fibers with a length of 1-3 mm, soaked in 7-8 g / L NaOH solution, and treated with constant temperature stirring at 65-75℃ for 1.2-1.8 h, with stirring once every 30 min during the process. After treatment, it is washed with deionized water until neutral and dried at 80℃ until the moisture content is ≤3%.

[0016] Preferably, the reinforcing agent in step S2 is one or more of nanocellulose, graphene, or chopped carbon fibers; the mass fraction of the reinforcing agent in the antibacterial reinforcing masterbatch is 2-6%; the mass fraction of each component of the antibacterial reinforcing masterbatch is as follows:

[0017] Antibacterial pigment powder 3-8%, high molecular carrier resin 65-80%, natural seaweed fiber 3-8%, dispersant 5-10%, stabilizer 2-5%, reinforcing agent 2-6%, environmentally friendly additives 0.5-1%.

[0018] Preferably, the polymer carrier resin in step S2 and the matrix resin in step S3 are the same type of resin, selected from recycled polyester, polylactic acid or polyamide; the mixing mass ratio of the matrix resin to the antibacterial reinforcing masterbatch is 85-95:5-15, and a silane coupling agent is also added in step S2 during mixing, the mass fraction of the silane coupling agent is 0.3-0.8%, which is used to enhance the interfacial bonding force between the antibacterial pigment, natural seaweed fiber, reinforcing agent and polymer carrier resin.

[0019] Preferably, the melt spinning process conditions in step S3 are as follows:

[0020] The screw speed is controlled at 80-120 r / min, the temperature of each heating zone is set in stages according to the melting characteristics of the material, the spinneret temperature is higher than the melting point of the matrix resin, the post-stretch ratio is controlled at 3.0-4.5 times, and the winding speed is controlled at 2800-3500 m / min.

[0021] An antibacterial and environmentally friendly masterbatch dyeing fiber is disclosed. This antibacterial and environmentally friendly masterbatch dyeing fiber comprises a composite fiber prepared by the method described above. The composite fiber includes a first fiber, a second fiber, and a third fiber. The first and second fibers are arranged in a reciprocating, interlaced pattern to form interlocking holes. The third fiber is twisted and interlaced between the interlocking holes formed by the first and second fibers. The first, second, and third fibers are homologous or heterologous fibers. The twist angle of the third fiber is 90°-180°, and its interlacing density is 5-15 interlocking holes per centimeter. The reciprocating, interlacing pattern of the first and second fibers is orthogonal or oblique, with an interlacing angle of 30°-90°. After interlacing, the third fiber forms a three-dimensional interlocking braided structure with the first and second fibers, and the porosity of the braided structure is 20-45%.

[0022] The technical effects and advantages of this invention are as follows:

[0023] (1) This invention uses GRAS-certified microbial fermentation to produce antibacterial pigments, abandoning traditional chemical antibacterial agents, ensuring the biosafety and environmental friendliness of the fiber, selecting environmentally friendly resins such as recycled polyester and polylactic acid, and adding natural seaweed fiber treated with alkali as a reinforcing and functional component, so that the final product has biodegradability and improves the antibacterial and degradation performance of the fiber.

[0024] (2) This invention obtains antibacterial pigment powder with a purity of ≥95% through fermentation and purification processes. It has high-efficiency inhibitory activity against Escherichia coli, Staphylococcus aureus, etc. The antibacterial pigment is integrated into the fiber body through masterbatch technology and the compatibility is improved by interface modifier. It achieves a long-lasting antibacterial effect with an antibacterial rate of not less than 90% after 50 washes.

[0025] (3) By introducing natural seaweed fiber and nanocellulose and other reinforcing agents into the masterbatch, the present invention forms a multi-scale and multi-dimensional reinforcing network, which improves the breaking strength of the fiber. By adding silane coupling agent and carrying out high-speed mixing treatment, the interfacial compatibility between polar fillers such as antibacterial pigments, natural seaweed fiber and reinforcing agents and non-polar polymer resins is improved, the interfacial bonding strength is improved, and the uniformity of the composite material in the melt spinning process and the mechanical stability of the final product are guaranteed. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0027] Figure 1 This is a flowchart illustrating the overall steps of the present invention;

[0028] Figure 2 This is a structural diagram of the composite fiber of the present invention.

[0029] In the picture:

[0030] 1. Composite fiber; 11. First fiber; 12. Second fiber; 13. Third fiber. Detailed Implementation

[0031] 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.

[0032] This invention provides, for example Figure 1 The image shows an antibacterial and environmentally friendly masterbatch dyed fiber.

[0033] Example 1: Specifically includes the following steps:

[0034] S1: Preparation of antibacterial agent: Select antibacterial pigment-producing strains that have been certified by GRAS, inoculate them into fermentation medium for liquid deep fermentation, and achieve high pigment production through feeding control and dissolved oxygen regulation during the fermentation process; the fermentation broth is subjected to solid-liquid separation, extraction, purification and drying to obtain antibacterial pigment powder. The sequence is as follows: the fermentation broth is subjected to solid-liquid separation to remove bacterial impurities, organic solvent extraction of pigment, chromatography purification and enrichment, and low-temperature drying to obtain antibacterial pigment powder with a purity ≥95%.

[0035] The GRAS-certified antimicrobial pigment-producing strains are one or more of the following: *Micrococcus luteus* ATCC4698, *Rhodosporidium toruloides* ATCC10657, or *Penicillium purpurogenum* ATCC20065, in a 1:1 or 1:1:1 ratio. The pigment yield of the strains is not less than 1.2 g / L, preferably 1.5-2.0 g / L. The antibacterial pigment is used to inhibit the activity of Escherichia coli and Staphylococcus aureus. The minimum inhibitory concentration (MIC) of the antibacterial pigment against Escherichia coli (ATCC25922) is ≤0.5 mg / mL, and the MIC against Staphylococcus aureus (ATCC25923) is ≤0.3 mg / mL. The antibacterial spectrum can also cover Candida albicans (ATCC10231). The antibacterial pigment is produced by microbial fermentation with GRAS certification, which abandons traditional chemical antibacterial agents and ensures the biosafety and environmental friendliness of the product from the source.

[0036] The fermentation medium includes a carbon source, a nitrogen source, inorganic salts, and a metabolism promoter. The carbon source is glucose, the nitrogen source is yeast extract and peptone, and the inorganic salts include potassium dihydrogen phosphate, magnesium sulfate, and ferrous sulfate. Tween-80 and L-tyrosine are also added to the medium. The mass concentrations of the fermentation medium are: glucose 18-22 g / L, yeast extract 7-9 g / L, peptone 4.5-5.5 g / L, potassium dihydrogen phosphate 1.8-2.2 g / L, magnesium sulfate 0.4-0.6 g / L, and ferrous sulfate 0.009-0.011 g / L, with the pH adjusted to 6.6-6.8. The metabolism promoters include 0.4-0.6% (v / v) Tween-80 and 0.9-1.1 g / L L-tyrosine, where Tween-80 is used to enhance pigment secretion efficiency, and L-tyrosine serves as a precursor for pigment synthesis. After preparation, the medium is autoclaved at 121°C for 30 minutes.

[0037] The process conditions for liquid submerged fermentation are as follows:

[0038] The inoculum size is controlled at 4-6%, the seed liquid concentration is controlled at the logarithmic growth phase of the cells, the fermentation process maintains a neutral pH environment, dissolved oxygen is controlled by stirring and aeration, the fermentation cycle is controlled at 48-72 hours, and a carbon source is added in the middle of the fermentation.

[0039] The specific process conditions for liquid submerged fermentation are as follows:

[0040] The inoculum size was controlled at 4.5-5.5% (v / v). The seed culture was then cultured in a secondary scale-up stage until the logarithmic growth phase of the cells. At this point, the OD of the seed culture was... 600 Value is 1.0-1.2, viable count ≥10 8 CFU / mL;

[0041] The fermentation equipment uses 50-500L mechanically stirred fermenters, with the fermentation temperature maintained at 29-31℃ and the pH maintained at 6.5-7.0 by automatically adding 1mol / L HCl or 1mol / L NaOH solution.

[0042] Dissolved oxygen is controlled by adjusting the stirring speed to 220-240 r / min and the aeration rate to 1.2-1.4 vvm to maintain the dissolved oxygen concentration at 20-30% saturation during fermentation.

[0043] The fermentation cycle is controlled at 55-65 hours. During the middle stage of fermentation (45-48h), 5-5.5 g / L glucose solution is added at a rate of 0.5-1.0 L / h, and the total amount added is 5-8% of the fermentation liquid volume.

[0044] The fermentation endpoint is determined as follows: fermentation is terminated when the pigment concentration in the fermentation broth no longer increases significantly (increase ≤5% within 24 hours) and the dry weight of the cells reaches 12-15 g / L.

[0045] The specific extraction and purification process of the fermentation broth is as follows:

[0046] Solid-liquid separation: The fermentation broth is filtered through a plate and frame filter to remove mycelium at a pressure of 0.25-0.35 MPa. The filtrate is then further purified by ceramic membrane microfiltration with a pore size of 0.15-0.25 μm.

[0047] Extraction: Add 65-75% (v / v) ethanol solution to the clear filtrate, with a filtrate to ethanol volume ratio of 1:2.5-3.5. Extract at a constant temperature of 50-55℃ with stirring for 1.5-2.5 hours. Repeat the extraction twice and combine the extracts.

[0048] Purification: The purification was carried out by silica gel column chromatography with a column size of Φ50×800mm and silica gel particle size of 200-300 mesh. The eluent was a mixture of petroleum ether and ethyl acetate (volume ratio 2:1) and the elution flow rate was 1-2 BV / h. The target elution peak was collected. By controlling fermentation and purification, an antibacterial pigment powder with a purity of ≥95% was obtained, which has high inhibitory activity against Escherichia coli, Staphylococcus aureus, etc.

[0049] Drying: The purified pigment solution is concentrated by vacuum rotary evaporation to a solid content ≥30%. The vacuum rotary evaporation concentration temperature is controlled at 40-45℃ and the vacuum degree is -0.075~-0.085MPa. Then, it is freeze-dried for 24-36h at a temperature of -40~-30℃ and a vacuum degree ≤10Pa to obtain antibacterial pigment powder with a moisture content ≤2.5%.

[0050] S2: Preparation of reinforced masterbatch: The antibacterial pigment powder obtained in step S1 above is mixed with polymer carrier resin, pretreated natural seaweed fiber, dispersant, stabilizer and reinforcing agent in proportion, and then melt-blended and extruded to obtain antibacterial reinforced masterbatch. An interface modifier needs to be added before it is fed into a twin-screw extruder for melt blending. The extruded strip is cooled and pelletized to obtain antibacterial reinforced masterbatch with uniform dispersion of antibacterial components and excellent mechanical stability.

[0051] Natural seaweed fiber is one or more of brown algae fiber, kelp fiber, or laver fiber. Brown algae fiber and kelp fiber are compounded at a mass ratio of 1:1 and used after alkali pretreatment. The mass fraction of natural seaweed fiber in the antibacterial reinforcing masterbatch is 3-8%. The pretreatment process of natural seaweed fiber is as follows: natural seaweed fiber is cut into short fibers with a length of 1-3 mm, soaked in 7-8 g / L NaOH solution, and treated with constant temperature stirring at 65-75℃ for 1.2-1.8 h, stirring once every 30 min. After treatment, it is washed with deionized water until neutral, and dried at 80℃ until the moisture content is ≤3%. The mass fraction of natural seaweed fiber in the antibacterial reinforcing masterbatch is 4-7%, its fiber diameter is 10-50 μm, and its breaking strength is ≥1.5 cN / dtex.

[0052] The reinforcing agent is one or more of nanocellulose, graphene, or chopped carbon fibers; the nanocellulose has a length of 50-200 nm and a diameter of 5-10 nm; the graphene has 3-10 layers and a sheet diameter of 0.5-2 μm; the chopped carbon fibers have a length of 50-100 μm and a diameter of 5-8 μm; the nanocellulose and graphene are compounded at a mass ratio of 2:1; the mass fraction of the reinforcing agent in the antibacterial reinforcing masterbatch is 3-5%.

[0053] The mass fraction of the reinforcing agent in the antibacterial reinforcing masterbatch is 2-6%; the mass fraction of each component in the antibacterial reinforcing masterbatch is as follows:

[0054] Antibacterial pigment powder 3-8%, high molecular weight carrier resin 65-80%, natural seaweed fiber 3-8%, dispersant 5-10%, stabilizer 2-5%, reinforcing agent 2-6%, environmentally friendly additives 0.5-1%;

[0055] The dispersant is a mixture of polyethylene glycol (PEG-6000) and ethylene-acrylic acid copolymer (EAA, acid value 100-150 mg KOH / g) in a mass ratio of 1:1; the stabilizer is a mixture of antioxidant 1010 and ultraviolet absorber UV-327 in a mass ratio of 2:1; and the environmentally friendly additive is biodegradable zinc stearate.

[0056] The polymer carrier resin is the same type of resin as the matrix resin in step S3, selected from recycled polyester, polylactic acid, or polyamide; the intrinsic viscosity of recycled polyester is 0.65-0.75 dL / g, the number-average molecular weight of polylactic acid is 80,000-120,000, and the relative viscosity of polyamide is 2.4-2.8. The mixing mass ratio of the matrix resin to the antibacterial reinforcing masterbatch is 85-95:5-15. In step S2, a silane coupling agent is also added during mixing. The silane coupling agent is KH-550 or KH-560, preferably KH-550, and the mass fraction of the silane coupling agent is 0.3-0.8%. This is used to enhance the interfacial bonding between the antibacterial pigment, natural seaweed fiber, reinforcing agent, and polymer carrier resin. After adding the silane coupling agent, the mixture is stirred in a high-speed mixer at 85-95℃ for 10-15 minutes to promote the reaction between the coupling agent and the surface hydroxyl groups of each component, thereby increasing the interfacial bonding strength by 30-50%. Environmentally friendly resins such as recycled polyester and polylactic acid are selected, and natural seaweed fiber treated with alkali is added as a reinforcing and functional component, so that the final fiber has excellent biodegradability or recyclability. By adding the silane coupling agent and carrying out high-speed mixing, the interfacial compatibility between polar fillers such as antibacterial pigments, natural seaweed fiber, and reinforcing agents and non-polar polymer resins is effectively improved, ensuring the uniformity of the composite material during melt spinning and the mechanical stability of the final product.

[0057] S3: Fiber spinning and forming: The antibacterial reinforced masterbatch obtained in step S2 above is mixed with the dried matrix resin in a set ratio, and after pretreatment, melt spinning, stretching and winding, antibacterial and environmentally friendly masterbatch dyeing reinforced fiber is obtained. Specifically, the antibacterial and environmentally friendly masterbatch dyeing reinforced fiber is obtained by melt plasticizing in a screw extruder, spinning in a spinneret, cooling and solidifying, multi-stage stretching, heat setting and winding.

[0058] The pretreatment process involves mixing the matrix resin with the antibacterial reinforced masterbatch, then drying it in a vacuum drying oven at 85-95℃ for 5-6 hours. The moisture content of the dried material is ≤0.3%.

[0059] The process conditions for melt spinning are as follows:

[0060] The screw speed is controlled at 80-120 r / min. The temperature of each heating zone is set in sections according to the melting characteristics of the material. The temperature of each zone of the screw extruder is as follows: feeding zone 185-195℃, compression zone 235-245℃, metering zone 245-255℃, spinneret temperature 255-265℃, of which recycled PET corresponds to 260-265℃, PLA corresponds to 245-250℃, and PA6 corresponds to 250-255℃.

[0061] The spinneret temperature is higher than the melting point of the matrix resin, the spinneret orifice diameter is 0.22-0.28mm, the number of spinneret orifices is 36-48, the post-stretch ratio is controlled at 3.0-4.5 times, and the winding speed is controlled at 2800-3500m / min.

[0062] Cooling and curing: Side-blowing cooling is used, with a cooling air temperature of 22-24℃, a wind speed of 0.7-0.9m / s, and a wind distance of 15-20cm;

[0063] Multi-stage stretching: Two-stage stretching is adopted. The first stage stretching temperature is (glass transition temperature +10~20℃), and the stretching ratio is 1.5-2.0 times. The second stage stretching temperature is (glass transition temperature +30~40℃), and the total stretching ratio is 3.5-4.2 times.

[0064] Heat setting: setting temperature 110-130℃, setting time 3-5s; winding speed 3000-3300m / min, winding tension 7-9cN.

[0065] S4: Reinforced Weaving: The antibacterial and environmentally friendly masterbatch dyed reinforcing fibers obtained in step S3 above are subjected to reinforced weaving treatment to form composite fiber 1. The antibacterial and environmentally friendly masterbatch dyed reinforcing fibers are used as warp yarns, and natural cotton fibers or regenerated cellulose fibers are used as weft yarns. Plain weave, twill weave or satin weave processes are used for reinforced weaving. The weaving density is controlled at 30-50 warp threads / cm and 25-40 weft threads / cm. After weaving, it is pre-shrinked and set to form composite fiber 1 with a dense structure and enhanced strength. Weaving is carried out on a rapier loom at a weaving speed of 200-300 r / min. The woven composite fiber 1 is pre-shrinked in a pre-shrinking machine at a temperature of 80-90℃ and a humidity of 60-70% with a pre-shrinking rate of 3-5%. The pre-shrinked composite fiber 1 is then set in a hot air setting machine at a temperature of 120-130℃ for 10-15 min. The dry heat shrinkage rate of the composite fiber after setting is ≤3%.

[0066] The prepared composite fiber 1 has an antibacterial rate of not less than 99% against Escherichia coli and Staphylococcus aureus, and an antibacterial rate of not less than 90% after 50 washes. The tensile strength is not less than 4.0 cN / dtex, the elongation at break is 15-28%, and the color difference is not higher than 3.0. After being reinforced by weaving, the axial tensile strength of the woven body is increased by more than 50% compared with the unwoven single fiber, and the interlaminar shear strength is not less than 15 MPa.

[0067] Example 2: Based on Example 1, an antibacterial and environmentally friendly masterbatch dyed fiber is also provided. This antibacterial and environmentally friendly masterbatch dyed fiber includes a composite fiber 1 prepared by the above-described method for preparing an antibacterial and environmentally friendly masterbatch dyed fiber. The composite fiber 1 comprises a first fiber 11, a second fiber 12, and a third fiber 13. The first fiber 11 and the second fiber 12 are arranged in a reciprocating staggered pattern to form cross holes. The third fiber 13 is twisted and inserted between the cross holes formed by the first fiber 11 and the second fiber 12. The first fiber 11, the second fiber 12, and the third fiber 13 are homologous or heterologous fibers. The twist angle of the third fiber 13 is 90°-180°, and its insertion density is 5-15 cross holes per centimeter. The first fiber 11... The second fiber 12 is arranged in an orthogonal or oblique cross-section with a cross angle of 30°-90°. After being inserted, the third fiber 13 forms a three-dimensional interlocked braided structure with the first fiber 11 and the second fiber 12. The porosity of the braided structure is 20-45%. The third fiber 13 is inserted into the cross-hole network formed by the first fiber 11 and the second fiber 12 at a specific twist angle. During the insertion process, the surface texture of the third fiber 13 generates friction with the cross-holes, which effectively locks the relative position of the first fiber 11 and the second fiber 12, prevents the braided structure from slipping and deforming during subsequent processing or use, improves the stability of the composite fiber 1 structure, and reduces the random loosening of the composite fiber 1 during use.

[0068] The porosity of the woven structure is 20%-45%, which provides a spatial carrier for the loading and sustained release of color masterbatch. When the porosity is below 20%, the loading capacity of the color masterbatch is limited, and the release channels of the antibacterial active ingredients are not smooth. When the porosity is above 45%, the compactness of the woven structure is insufficient, and the strength of the fiber assembly decreases significantly. The pore size distribution exhibits a bimodal characteristic: the main pores formed by the intersection of the first fiber 11 and the second fiber 12 have a pore size of 50-200 micrometers, while the secondary pores formed by the segmentation after the third fiber 13 is inserted have a pore size of 10-50 micrometers. This hierarchical pore structure is conducive to achieving selective distribution of color masterbatch—the color masterbatch carrier resin with a larger particle size preferentially fills the main pores, while the antibacterial active ingredients with a smaller particle size penetrate into the secondary pores, forming a gradient functionalized structure.

[0069] The composite fiber 1 has a high loft in its braided structure, giving it lightweight and warm properties, and the hollow channels can serve as additional space for the slow release of antibacterial agents. The cross-sectional shapes of the first fiber 11, the second fiber 12, and the third fiber 13 can be the same or different. When a combination of heteromorphic homologous fibers is used, the pore morphology and mechanical anisotropy of the braided structure can be further optimized. When the first fiber 11, the second fiber 12, and the third fiber 13 are homologous fibers, they have the same chemical composition and thermodynamic properties, and their shrinkage behavior is consistent during subsequent heat setting, resulting in excellent dimensional stability of the braided structure. When the first fiber 11, the second fiber 12, and the third fiber 13 are heterologous fibers, the different properties of the fibers can be used to achieve functional complementarity. For example, the first fiber 11 and the second fiber 12 can be made of polyester fiber to provide strength support, and the third fiber 13 can be made of polyamide fiber to enhance abrasion resistance and dyeing affinity, or the third fiber 13 can be made of modified polyester fiber containing antibacterial groups to enhance antibacterial function. When combining heterogeneous fibers, attention must be paid to the interfacial compatibility. This can be achieved by introducing a compatibility coating on the fiber surface or controlling the heat setting temperature window, so that different fibers can form a moderate fusion bond at the interface, which can ensure the integrity of the structure and avoid the deterioration of the fiber properties.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an antibacterial and environmentally friendly color master dyeing fiber, characterized in that, Specifically, the following steps are included: S1: Preparation of antibacterial agent: Select antibacterial pigment producing strains that have been certified by GRAS, inoculate them into fermentation medium for liquid deep fermentation, and then separate, extract, purify and dry the fermentation broth to obtain antibacterial pigment powder; S2: Preparation of enhanced masterbatch: The antibacterial pigment powder obtained above is mixed with polymer carrier resin, natural seaweed fiber, dispersant, stabilizer and reinforcing agent in proportion, and then melt-blended and extruded to granulate to obtain antibacterial enhanced masterbatch; S3: Fiber spinning and forming: The antibacterial reinforced masterbatch obtained above is mixed with the matrix resin, and after pretreatment, melt spinning, stretching and winding, antibacterial and environmentally friendly masterbatch dyeing reinforced fiber is obtained. S4: Reinforced weaving: The antibacterial and environmentally friendly masterbatch dyeing and reinforcing fibers obtained above are subjected to reinforced weaving treatment to form composite fibers (1).

2. The method for preparing the antibacterial and environment-friendly color master dyeing fiber according to claim 1, characterized in that, The GRAS-certified antimicrobial pigment-producing strain in step S1 is one or more of Micrococcus luteus, Rhodotorula glutinis, or Penicillium purpureum, and the pigment yield of the strain is not less than 1.2 g / L. The antimicrobial pigment is used to inhibit the activity of Escherichia coli and Staphylococcus aureus.

3. The method as claimed in claim 1, wherein the method of preparing the anti-bacterial, environment-friendly color master dyeing fiber is characterized by, The fermentation medium in step S1 includes a carbon source, a nitrogen source, inorganic salts, and a metabolism promoter; wherein the carbon source is glucose, the nitrogen source is yeast extract and peptone, and the inorganic salts include potassium dihydrogen phosphate, magnesium sulfate, and ferrous sulfate; the medium also contains Tween-80 and L-tyrosine.

4. The method as claimed in claim 1, wherein the method of preparing the anti-bacterial, environment-friendly color master dyeing fiber is characterized by, The process conditions for the liquid deep fermentation in step S1 are as follows: The inoculum size is controlled at 4-6%, the seed culture concentration is controlled at the logarithmic growth phase of the cells, a neutral pH environment is maintained during fermentation, dissolved oxygen is controlled by stirring and aeration, the fermentation cycle is controlled at 48-72 hours, and a carbon source is added in the middle of fermentation.

5. The method as claimed in claim 1, wherein the method of preparing the anti-bacterial, environment-friendly color master dyeing fiber is characterized by, The natural seaweed fiber in step S2 is one or more of brown algae fiber, kelp fiber or laver fiber, and is used after pretreatment with alkali solution; the mass fraction of the natural seaweed fiber in the antibacterial enhanced color masterbatch is 3-8%.

6. The method for preparing antibacterial and environmentally friendly masterbatch dyed fiber according to claim 5, characterized in that, The natural seaweed fiber pretreatment process in step S2 is as follows: cut the natural seaweed fiber into short fibers with a length of 1-3 mm, soak them in 7-8 g / L NaOH solution, and treat them with constant temperature stirring at 65-75℃ for 1.2-1.8 h, stirring once every 30 min during the process. After treatment, wash them with deionized water until neutral, and dry them at 80℃ until the moisture content is ≤3%.

7. The method for preparing antibacterial and environmentally friendly masterbatch dyed fiber according to claim 1, characterized in that, In step S2, the reinforcing agent is one or more of nanocellulose, graphene, or chopped carbon fibers; the mass fraction of the reinforcing agent in the antibacterial reinforcing masterbatch is 2-6%; the mass fraction of each component in the antibacterial reinforcing masterbatch is as follows: Antibacterial pigment powder 3-8%, high molecular carrier resin 65-80%, natural seaweed fiber 3-8%, dispersant 5-10%, stabilizer 2-5%, reinforcing agent 2-6%, environmentally friendly additives 0.5-1%.

8. The method as claimed in claim 1, wherein the method of preparing the anti-bacterial, environment-friendly color master dyeing fiber is characterized by, The polymer carrier resin in step S2 is the same type of resin as the matrix resin in step S3, selected from recycled polyester, polylactic acid, or polyamide; the mixing mass ratio of the matrix resin to the antibacterial reinforcing masterbatch is 85-95:5-15, and a silane coupling agent is also added in step S2 during mixing, the mass fraction of the silane coupling agent is 0.3-0.8%, which is used to enhance the interfacial bonding force between the antibacterial pigment, natural seaweed fiber, reinforcing agent and polymer carrier resin.

9. The method as claimed in claim 1, wherein the method of preparing the anti-bacterial, environment-friendly color master dyeing fiber is characterized by, The melt spinning process conditions in step S3 are as follows: The screw speed is controlled at 80-120 r / min, the temperature of each heating zone is set in stages according to the melting characteristics of the material, the spinneret temperature is higher than the melting point of the matrix resin, the post-stretch ratio is controlled at 3.0-4.5 times, and the winding speed is controlled at 2800-3500 m / min.

10. An antibacterial eco-friendly color masterbatch dyed fiber, characterized by, The antibacterial and environmentally friendly masterbatch dyeing fiber includes a composite fiber (1) prepared by a method for preparing antibacterial and environmentally friendly masterbatch dyeing fiber as described in any one of claims 1-9. The composite fiber (1) comprises a first fiber (11), a second fiber (12), and a third fiber (13). The first fiber (11) and the second fiber (12) are arranged in a reciprocating staggered pattern to form a cross hole. The third fiber (13) is twisted and inserted between the cross holes formed by the first fiber (11) and the second fiber (12). The second fiber (12) and the third fiber (13) are homologous or heterologous fibers; the twist angle of the third fiber (13) is 90°-180°, and its interlacing density is 5-15 interlacing holes per centimeter. The reciprocating interlacing of the first fiber (11) and the second fiber (12) is arranged orthogonally or obliquely, with an interlacing angle of 30°-90°. After interlacing, the third fiber (13) forms a three-dimensional interlocked braided structure with the first fiber (11) and the second fiber (12), and the porosity of the braided structure is 20-45%.

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