Fiber modification treatment process and application thereof in kapok fiber fabric

Abstract

The invention discloses a fiber modification treatment process and application of the fiber modification treatment process in kapok fiber fabric, and relates to the technical field of textile, and the technical key points comprise the following steps: step (1) fine opening and picking: processing kapok fibers by adopting low-speed and light-striking opening and picking equipment, controlling the speed of a beater to be 400-600r / min, and performing pre-opening through a cotton loosening machine; (2) removing and grading short fibers, namely removing the short fibers with the length of less than 6mm by using an airflow grader or a vibrating screen, controlling the short fiber rate to be below 10%, and dividing the kapok fibers into grades of 10-20mm, 20-30mm and the like according to the length; by virtue of the synergistic effect of the low-temperature plasma and the natural antibacterial slurry, the antibacterial rate of the fabric on the three pathogenic bacteria reaches a relatively high standard; through low-damage pretreatment and structure optimization, the breaking strength of the fibers is improved, and the inherent defects that kapok fibers are poor in cohesive force and prone to breakage are overcome.

Description

Technical Field

[0001] The invention relates to the technical field of textiles, in particular to a fiber modification process and application thereof in kapok fiber fabrics. Background Art

[0002] Kapok fiber, a natural, renewable resource, boasts broad application prospects in textiles, healthcare, and environmentally friendly materials due to its unique physical and chemical properties, including light weight, high hollowness, excellent thermal insulation, and strong moisture absorption. As one of the lightest known natural fibers, it offers irreplaceable advantages in the development of lightweight thermal insulation materials. Existing techniques for processing kapok fiber have significant shortcomings in improving its antibacterial properties, making it difficult to meet the demands of high-end applications. Traditional processes focus primarily on improving the mechanical properties and processability of kapok fiber, but lack targeted optimization of its antibacterial properties. Physical treatments such as mechanical combing only improve fiber uniformity but fail to impart antibacterial properties. Chemical modification, including impregnation with inorganic antimicrobial agents such as silver ions, can improve antibacterial rates in the short term, but carries the risk of heavy metal residues.

[0003] Furthermore, deficiencies in the pretreatment steps of existing processes further exacerbate the lack of antibacterial properties. For example, excessively high beater speeds during the cleaning phase increase fiber breakage, resulting in a loose, localized structure of short fibers and broken fibers that, in turn, become a breeding ground for microorganisms. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a fiber modification treatment process, which can achieve a higher level of antibacterial rate of fabrics against three types of pathogens by relying on the synergistic effect of low-temperature plasma and natural antibacterial slurry.

[0005] To achieve the above object, the present invention provides the following technical solution: a fiber modification process, comprising the following steps: Step (1) Fine opening and cleaning: The kapok fibers are processed using a low-speed, light-beating opening and cleaning device, with the beater speed controlled at 400-600 r / min, and pre-opening is performed by a loosening machine; Step (2) Short lint removal and classification: Use an airflow classifier or a vibrating screen to remove short lint less than 6 mm in length, so that the short lint rate is controlled below 10%, and the kapok fibers are classified into two grades: 10-20 mm and 20-30 mm; Step (3) kapok fiber modification treatment: Nitrogen and oxygen mixed low-temperature plasma treatment: using a mixed gas of 85% N2 and 15% O2 by volume, power 60-100W, and treatment time 4-6 minutes; Chitosan-starch composite sizing treatment: using a composite slurry containing 5-10% water-soluble quaternized chitosan (degree of substitution ≥85%) and 90-95% oxidized starch, with the total amount of the slurry not exceeding 5% of the dry weight of the kapok fiber, to obtain modified kapok fiber.

[0006] Preferably, the power of the low-temperature plasma treatment in step (3) is 70-90 W, and the treatment time is 5 min.

[0007] Preferably, the quaternized chitosan in the composite slurry in step (3) accounts for 8% of the total amount of the slurry.

[0008] Preferably, the method further includes a combing process for the modified kapok fiber: using a carding machine with a cylinder card cloth having a tooth density of 300-400 teeth / 25.4 mm and a tooth depth of 0.5-0.8 mm, the cylinder speed is controlled at 250-350 r / min, the distance between the cylinder and the cover plate is 0.18-0.25 mm, the distance between the cylinder and the doffer is 0.15-0.2 mm, and a negative pressure suction device is arranged around the carding machine to obtain the combed kapok fiber.

[0009] Preferably, the carded kapok fiber is subjected to a drawing and stretching process: 6-8 cotton strips are combined, the total stretching multiple is controlled at 5-8 times, the front zone stretching multiple does not exceed 3 times, and the roller spacing is adjusted according to the main length of the fiber. When the main length is 20 mm, the spacing is set to 22-25 mm.

[0010] The invention discloses an application of fiber-modified kapok fiber in fabrics. The kapok fiber fabric has an antibacterial rate of greater than 99% against Staphylococcus aureus ATCC 6538, an antibacterial rate of greater than 90% against Escherichia coli ATCC 8739, and an antibacterial rate of greater than 88% against Candida albicans ATCC10231.

[0011] Compared with the existing technology, the present invention provides a fiber modification process and its application in kapok fiber fabrics, which has the following beneficial effects: the present invention uses the synergistic effect of low-temperature plasma and natural antibacterial slurry to make the fabric's inhibition rate against three types of pathogens reach a higher standard; after low-damage pretreatment and structural optimization, the fiber breaking strength is improved, and the inherent defects of kapok fiber such as poor cohesion and easy breakage are solved; at the same time, the fiber uniformity and straightness are significantly improved, spinning defects are reduced, and whiteness is significantly improved, achieving both excellent processing and quality; the process has no chemical pollution emissions, natural slurry replaces synthetic raw materials, and energy consumption is reduced, which is in line with the trend of green environmental protection and sustainable development, and is compatible with existing equipment, with stable pilot production capacity, reduced processing costs, and strong industrial adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a microscopic scan of the product prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0013] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0014] Figure 1 This is a scanning electron microscope (SEM) image, obtained using the corresponding test method GB / T 36422-2018, "Electron Microscopy of Textiles." It was used to observe the microscopic morphology of kapok fiber or its fabric samples. Key image information is as follows: Magnification: ×1.5K (1500x), clearly showing the microstructural details of the fiber surface. Scale bar: 30μm.

[0015] Image acquisition method (according to GB / T 36422-2018) 1. Sample Pretreatment Sampling: Cut a sample of appropriate size (usually a few millimeters square) from the kapok fiber or fabric to be tested.

[0016] Drying: If the sample contains moisture, it must be dried first (such as vacuum drying, freeze drying) to prevent moisture from affecting electron microscopy observation.

[0017] Gold coating: The sample is sprayed with gold (or platinum) (through an ion sputtering device) to increase the conductivity of the sample surface, prevent charge accumulation during electron beam irradiation, and ensure clear imaging.

[0018] 2. Scanning Electron Microscope Observation Sample loading: Fix the gold-sprayed sample on the electron microscope sample stage and place it in the sample chamber of the scanning electron microscope.

[0019] Parameter setting: Adjust the electron microscope parameters according to the sample characteristics, including: Accelerating voltage: usually 5–20 kV (5–10 kV is recommended for insulating samples such as kapok fibers to avoid damage to the sample by the high-energy electron beam); Working distance: 10–15 mm, balancing imaging resolution and depth of field; Magnification: Adjust to ×1.5K (1500 times) to clearly show the fiber microstructure (such as surface texture and slurry attachment morphology).

[0020] (1) Antibacterial rate test Reference standard: GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles Part 3: Oscillation method" Detailed test steps: (1) Preparation of bacterial solution: Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, and Candida albicans ATCC 10231 were inoculated into the corresponding culture medium, cultured at an appropriate temperature until the logarithmic growth phase, and diluted with phosphate buffer to a concentration of 10^5 - 10^6 CFU / mL.

[0021] (2) Sample preparation: Cut the fabric to be tested into small pieces of about 1g, place them in a sterilized conical flask, add 50mL of the above bacterial solution, and set up a blank control group (only add bacterial solution, no sample).

[0022] (3) Oscillating culture: Place the conical flask in a shaker and culture at 37°C and 120 r / min for 18-24 hours.

[0023] (4) Counting viable bacteria: After the culture is completed, take 1 mL of bacterial solution and perform gradient dilution with phosphate buffer. Select an appropriate dilution multiple and spread 0.1 mL of the dilution solution on an agar plate. After incubation at an appropriate temperature for 24-48 hours, count the number of colonies on the plate.

[0024] Calculation formula: The inhibition rate is equal to (the average colony count of the blank control group minus the average colony count of the experimental group) divided by the average colony count of the blank control group, multiplied by 100%.

[0025] (2) Fracture strength test Reference standard: GB / T 3923.1-2013 "Tensile properties of textile fabrics - Part 1: Determination of breaking strength and elongation at break (strip method)" Detailed test steps: (1) Sample preparation: Cut samples with a width of 50 mm and a length of not less than 200 mm from the fabric to be tested. Cut at least 5 samples for each group. The long side of the sample should be parallel to the warp or weft direction of the fabric.

[0026] (2) Instrument calibration: Calibrate the tensile testing machine according to the instrument manual, set the clamping distance to 100 mm and the tensile speed to 100 mm / min.

[0027] (3) Clamping the sample: Clamp the two ends of the sample in the upper and lower clamps of the tensile testing machine respectively, ensuring that the sample is flat, wrinkle-free, and clamped evenly in the clamps.

[0028] (4) Tensile test: Start the tensile testing machine and record the maximum strength when the sample breaks.

[0029] (5) Calculation of breaking strength: Calculate the breaking strength based on the breaking strength and linear density of each sample and take the average value.

[0030] Calculation formula: Breaking strength is equal to the maximum force when the sample breaks divided by the linear density of the sample.

[0031] (3) Whiteness test Reference standard: GB / T 8424.2-2001 "Textiles - Colour fastness tests - Instrumental evaluation method for relative whiteness" Detailed test steps: (1) Instrument calibration: Calibrate the whiteness meter according to the instrument manual and use a standard white board and a standard black board for calibration.

[0032] (2) Sample preparation: Lay the fabric to be tested flat on the sample table, ensuring that there are no wrinkles or stains on the surface of the fabric.

[0033] (3) Measuring whiteness: Aim the measuring head of the whiteness meter at the surface of the fabric, perform multiple measurements (at least 3 times), and take the average value as the whiteness value of the fabric.

[0034] Note: The whiteness value is directly measured by a whiteness meter without the need for additional calculation formulas. Its value reflects the whiteness of the fabric.

[0035] Example 1: A fiber modification process, specifically comprising the following steps: Step (1) Fine opening and cleaning: The kapok fibers are processed using a low-speed, light-beating opening and cleaning device, with the beater speed controlled at 400 r / min, and pre-opening is performed by a loosening machine; Step (2) Short lint removal and classification: Use an airflow classifier to remove short lint less than 6 mm in length, control the short lint rate to 8%, and classify the kapok fibers into two grades of 10-20 mm and 20-30 mm; Step (3) kapok fiber modification treatment: Nitrogen and oxygen mixed low-temperature plasma treatment: using a mixed gas of 85% N2 and 15% O2 by volume, power 60W, and treatment time 4 minutes; Chitosan-starch composite sizing treatment: using a composite sizing agent containing 5% water-soluble quaternized chitosan (degree of substitution ≥ 85%) and 95% oxidized starch, with the total amount of the sizing agent being 3% of the dry weight of the kapok fiber, to obtain modified kapok fiber; Step (4) carding process: a carding machine with a cylinder card cloth having a tooth density of 300 teeth / 25.4 mm and a tooth depth of 0.5 mm is used, the cylinder speed is controlled at 250 r / min, the spacing between the cylinder and the cover is 0.18 mm, the spacing between the cylinder and the doffer is 0.15 mm, and a negative pressure suction device is set around the carding machine to obtain the carded kapok fiber; Step (5) drawing and stretching process: 6 slivers are combined, the total drafting multiple is controlled at 5 times, the front zone drafting multiple is 2 times, and the roller gauge is adjusted according to the main length of the fiber. When the main length is 20 mm, the gauge is set to 22 mm.

[0036] In the second embodiment, step (1) fine cotton opening and cleaning: the kapok fibers are processed by using a low-speed, light-beating cotton opening and cleaning device, the beater speed is controlled at 500 r / min, and the fibers are pre-opened by a loosening machine; Step (2) Short lint removal and classification: Use a vibrating screen to remove short lint less than 6 mm in length, control the short lint rate to 7%, and classify the kapok fibers into two grades of 10-20 mm and 20-30 mm; Step (3) kapok fiber modification treatment: Nitrogen and oxygen mixed low-temperature plasma treatment: using a mixed gas of 85% N2 and 15% O2 by volume, power 80W, and treatment time 5 minutes; Chitosan-starch composite sizing treatment: using a composite sizing agent containing 8% water-soluble quaternized chitosan (degree of substitution ≥ 85%) and 92% oxidized starch, with the total amount of the sizing agent being 4% of the dry weight of the kapok fiber, to obtain modified kapok fiber; Step (4) carding process: a carding machine with a cylinder card cloth having a tooth density of 350 teeth / 25.4 mm and a tooth depth of 0.6 mm is used, the cylinder speed is controlled at 300 r / min, the spacing between the cylinder and the cover is 0.2 mm, the spacing between the cylinder and the doffer is 0.18 mm, and a negative pressure suction device is set around the carding machine to obtain the carded kapok fiber; Step (5) drawing and stretching process: 7 slivers are combined, the total drafting ratio is controlled at 6 times, the front zone drafting ratio is 2.5 times, and the roller gauge is adjusted according to the main length of the fiber. When the main length is 20 mm, the gauge is set to 23 mm.

[0037] Example 3, step (1) fine opening and cleaning: using a low-speed, light-beating opening and cleaning device to process the kapok fibers, with the beater speed controlled at 600 r / min, and firstly using a loosening machine for pre-opening; Step (2) Short lint removal and classification: Use an airflow classifier to remove short lint less than 6 mm in length, control the short lint rate to 9%, and classify the kapok fibers into two grades of 10-20 mm and 20-30 mm; Step (3) kapok fiber modification treatment: Nitrogen and oxygen mixed low-temperature plasma treatment: using a mixed gas of 85% N2 and 15% O2 by volume, power 100W, and treatment time 6 minutes; Chitosan-starch composite sizing treatment: using a composite sizing agent containing 10% water-soluble quaternized chitosan (degree of substitution ≥ 85%) and 90% oxidized starch, with the total amount of the sizing agent being 5% of the dry weight of the kapok fiber, to obtain modified kapok fiber; Step (4) carding process: a carding machine with a cylinder card cloth having a tooth density of 400 teeth / 25.4 mm and a tooth depth of 0.8 mm is used, the cylinder speed is controlled at 350 r / min, the spacing between the cylinder and the cover is 0.25 mm, the spacing between the cylinder and the doffer is 0.2 mm, and a negative pressure suction device is set around the carding machine to obtain the carded kapok fiber; Step (5) drawing and stretching process: 8 slivers are combined, the total drafting multiple is controlled at 8 times, the front zone drafting multiple is 3 times, and the roller gauge is adjusted according to the main length of the fiber. When the main length is 20 mm, the gauge is set to 25 mm.

[0038] Example 4: Step (1) Fine opening and cleaning: The kapok fibers are processed using a low-speed, light-beating opening and cleaning device, with the beater speed controlled at 500 r / min, and pre-opening is performed by a loosening machine; Step (2) Short lint removal and classification: Use a vibrating screen to remove short lint less than 6 mm in length, control the short lint rate to 8%, and classify the kapok fibers into two grades of 10-20 mm and 20-30 mm; Step (3) kapok fiber modification treatment: Nitrogen and oxygen mixed low-temperature plasma treatment: using a mixed gas of 85% N2 and 15% O2 by volume, power 80W, and treatment time 5 minutes; Chitosan-starch composite sizing treatment: using a composite sizing agent containing 8% water-soluble quaternized chitosan (degree of substitution ≥ 85%) and 92% oxidized starch, with the total amount of the sizing agent being 4% of the dry weight of the kapok fiber, to obtain modified kapok fiber; Step (4) carding process: a carding machine with a cylinder card cloth having a tooth density of 350 teeth / 25.4 mm and a tooth depth of 0.6 mm is used, the cylinder speed is controlled at 300 r / min, the spacing between the cylinder and the cover is 0.2 mm, the spacing between the cylinder and the doffer is 0.18 mm, and a negative pressure suction device is set around the carding machine to obtain the carded kapok fiber; Step (5) drawing and stretching process: 7 slivers are combined, the total drafting ratio is controlled at 6 times, the front zone drafting ratio is 2.5 times, and the roller gauge is adjusted according to the main length of the fiber. When the main length is 20 mm, the gauge is set to 23 mm.

[0039] Comparative Example 1: The difference from Example 1 is that the beating speed in step (1) is 700 r / min, and the other steps and parameters are the same.

[0040] Comparative Example 2: The difference from Example 1 is that the short fibers are not removed in step (2), the short fiber rate is 25%, and the other steps and parameters are the same.

[0041] Comparative Example 3: The difference from Example 1 is that the volume ratio of the gases used in the low-temperature plasma treatment in step (3) is 70% N2 and 30% O2, and the remaining steps and parameters are the same.

[0042] Comparative Example 4: The difference from Example 1 is that the low-temperature plasma treatment power in step (3) is 50 W, and the other steps and parameters are the same.

[0043] Comparative Example 5: The difference from Example 1 is that the low-temperature plasma treatment time in step (3) is 3 minutes, and the other steps and parameters are the same.

[0044] Comparative Example 6: The difference from Example 1 is that in step (3), the quaternized chitosan in the composite slurry accounts for 3% of the total slurry, and the remaining steps and parameters are the same.

[0045] The kapok fibers obtained in the above-mentioned Examples 1, 2, 3 and 4 are made into kapok fiber fabrics through the following steps: Kapok fiber is used for spinning and then weaving fabrics. The spinning adopts air-spinning, friction spinning or ring spinning. The rotor speed of air-spinning or friction spinning is controlled at 30,000-50,000 r / min, and the spindle speed of ring spinning is controlled at 8,000-12,000 r / min. The yarn twist is 10%-20% higher than that of cotton yarn with the same linear density, and Z twist is adopted.

[0046] During the spinning process, a closed suction system is arranged around the spinning machine, and the suction negative pressure is controlled at 80-120Pa.

[0047] It also includes a blending process: blending the kapok fiber treated by the process with cotton, viscose or polyester fiber, with the blending ratio of the kapok fiber being 30%-50%, and the blending is carried out in the opening and cleaning stage.

[0048] During the fabric weaving process, the temperature in the spinning workshop is maintained at 25-30°C, the relative humidity is controlled at 60%-70%, and the moisture regain of the kapok fiber is controlled at 8%-10%.

[0049] The kapok fiber fabrics prepared in Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, 3, 4, 5, and 6 were grouped as MMXW-ML-01, MMXW-ML-02, MMXW-ML-03, MMXW-ML-04, MMXW-ML-05, MMXW-ML-06, MMXW-ML-07, MMXW-ML-08, MMXW-ML-09, and MMXW-ML-10, respectively. Antibacterial properties of the products in Examples and Comparative Examples were tested using the shaking flask method with Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, and Candida albicans ATCC 10231. The antibacterial rates were calculated using the shaking flask method. The breaking strength and whiteness of the fibers were also tested. The test results are detailed in Tables 1 and 2.

[0050] Table 1

[0051] Table 2

[0052] The present invention utilizes a low-speed (400-600 r / min) and light-blow opening and cleaning device, followed by pre-opening with a loosening machine. Test data shows that Example 1 achieved a breaking strength of 3.1 cN / tex at a beater speed of 400 r / min, while Comparative Example 1 achieved a breaking strength of only 2.4 cN / tex at a beater speed of 700 r / min. Furthermore, various antibacterial properties were lower than those of Example 1. This is because the low-speed, light-blow process reduces damage to kapok fibers during the opening and cleaning process, preventing disruption of the fiber structure and thereby preserving the fiber's original mechanical properties. It also provides a more complete fiber base for subsequent modification, facilitating the attachment and effectiveness of antibacterial substances, thereby enhancing the antibacterial properties of the fabric. The present invention removes short fibers with a length of less than 6 mm through an air flow classifier or a vibrating screen, controls the short fiber rate to below 10%, and grades the fibers by length. In Example 1, the short fiber rate is 8% and the breaking strength is 3.1 cN / tex, while in Comparative Example 2, the short fibers are not removed, the breaking strength is only 2.2 cN / tex, and the antibacterial rate is also significantly reduced. The presence of short fibers will lead to a decrease in the cohesion between fibers, affecting the overall strength of the fibers. In addition, the short fibers are prone to entanglement and agglomeration during subsequent processing, which is not conducive to uniform sizing and plasma treatment, thereby reducing the antibacterial effect. After removing the short fibers and grading them, the uniformity of the fiber length is improved, which can make subsequent processing more uniform and significantly improve the strength and antibacterial properties of the fabric. Low-temperature plasma treatment of a mixture of nitrogen and oxygen: The present invention adopts a mixed gas of 85% N2 and 15% O2 in a volume ratio, a power of 60-100W, and a treatment time of 4-6min. Comparative Example 3 adopts a mixed gas of 70% N2 and 30% O2, and its various performance indicators are lower than those of Example 1; Comparative Example 4 has a power of 50W and a treatment time of 3min, and its performance is also far inferior to that of Example 1. The appropriate gas ratio can introduce an appropriate amount of polar groups on the fiber surface and enhance the surface activity of the fiber, while the appropriate power and time can ensure the modification effect of the plasma on the fiber surface, which will neither cause insufficient modification due to insufficient treatment nor cause fiber damage due to excessive treatment. After this treatment, the fiber surface is easier to combine with the subsequent chitosan-starch composite slurry, laying the foundation for improving the antibacterial performance and strength.

[0053] Chitosan-starch composite sizing treatment: The present invention uses a composite slurry containing 5-10% water-soluble quaternized chitosan and 90-95% oxidized starch, and the total amount of slurry does not exceed 5% of the dry weight of the kapok fiber. In Example 1, when the quaternized chitosan accounted for 5%, the antibacterial effect was good, while in the comparative example VI, when the quaternized chitosan accounted for 3%, the antibacterial rate decreased significantly. Quaternized chitosan has excellent antibacterial properties. After compounding with oxidized starch, it can not only exert the antibacterial effect of chitosan, but also utilize the film-forming and adhesive properties of starch to improve the bonding force between fibers, thereby improving the breaking strength of the fabric. At the same time, controlling the total amount of slurry can avoid fiber stiffness caused by excessive slurry, which affects the feel and performance of the fabric. Example 4, which incorporates carding and drawing and drafting processes, achieved a breaking strength of 3.9 cN / tex, exceeding the 3.1 cN / tex achieved in Example 1, which did not incorporate these processes. This invention utilizes a carding machine with specific parameters (cylinder card cloth with a tooth density of 300-400 teeth / 25.4 mm and a tooth depth of 0.5-0.8 mm) and a drawing and drafting process (combining 6-8 slivers and a total draft ratio of 5-8), which further straightens and parallelizes the fibers, reduces fiber hooking and curling, improves fiber alignment, and enhances fiber cohesion, thereby significantly increasing fiber breaking strength. Furthermore, a negative pressure suction device surrounding the carding machine effectively removes short fibers and impurities generated during the carding process, preventing their impact on fiber properties.

[0054] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are all included in the scope of protection of the present invention.

Claims

1. A fiber modification process, characterized in that: The following steps are involved: Step (1) Fine opening and cleaning: The kapok fibers are processed using a low-speed, light-beating opening and cleaning device, with the beater speed controlled at 400-600 r / min, and pre-opening is performed by a loosening machine; Step (2) Short lint removal and classification: Use an airflow classifier or a vibrating screen to remove short lint less than 6 mm in length, so that the short lint rate is controlled below 10%, and the kapok fibers are classified into two grades: 10-20 mm and 20-30 mm; Step (3) kapok fiber modification treatment: Nitrogen and oxygen mixed low-temperature plasma treatment: using a mixed gas of 85% N2 and 15% O2 by volume, power 60-100W, and treatment time 4-6 minutes; Chitosan-starch composite sizing treatment: using a composite slurry containing 5-10% water-soluble quaternized chitosan (degree of substitution ≥85%) and 90-95% oxidized starch, with the total amount of the slurry not exceeding 5% of the dry weight of the kapok fiber, to obtain modified kapok fiber.

2. A fiber modification process according to claim 1, characterized in that: The power of the low-temperature plasma treatment in step (3) is 70-90 W, and the treatment time is 5 min.

3. The fiber modification process according to claim 1, characterized in that: The quaternized chitosan in the composite slurry in step (3) accounts for 8% of the total slurry.

4. The fiber modification process according to claim 1, characterized in that: It also includes a combing process for modified kapok fibers: a carding machine with a cylinder card cloth having a tooth density of 300-400 teeth / 25.4 mm and a tooth depth of 0.5-0.8 mm is used, the cylinder speed is controlled at 250-350 r / min, the distance between the cylinder and the cover plate is 0.18-0.25 mm, the distance between the cylinder and the doffer is 0.15-0.2 mm, and a negative pressure suction device is set around the carding machine to obtain the combed kapok fibers.

5. A fiber modification process according to claim 4, characterized in that: The carded kapok fibers are subjected to drawing and drafting processes: 6-8 slivers are combined, the total drafting multiple is controlled at 5-8 times, and the drafting multiple in the front zone does not exceed 3 times.

6. Use of the modified kapok fiber according to any one of claims 1 to 5 in fabrics, characterized in that: The kapok fiber fabric has an antibacterial rate of more than 99% against Staphylococcus aureus ATCC 6538, an antibacterial rate of more than 90% against Escherichia coli ATCC 8739, and an antibacterial rate of more than 88% against Candida albicans ATCC 10231.

Images