Antibacterial polypropylene fiber and preparation method thereof

Abstract

The invention belongs to the technical field of polypropylene fibers, and provides an antibacterial polypropylene fiber and a preparation method thereof, the polypropylene fiber comprises the following raw materials by weight: 92-100 parts of polypropylene, 6-10 parts of modified chitosan, 5-8 parts of zinc oxide, 3-6 parts of a flexibilizer, 1-2 parts of a lubricant, and 0.5-1 part of an antioxidant. The preparation method comprises the following steps: step 1, weighing polypropylene, modified chitosan, zinc oxide, a flexibilizer, a lubricant and an antioxidant in parts by weight, adding the materials into a mixer, uniformly mixing, then putting into a twin-screw extruder, and carrying out melt extrusion granulation to obtain master batches; and 2, carrying out melt spinning on the dried master batch, winding into a coil, and drafting and shaping to obtain the antibacterial polypropylene fiber. The polypropylene fiber prepared by the invention has good antibacterial property, antibacterial durability and mechanical property.

Description

Technical Field

[0001] This invention belongs to the field of polypropylene fiber technology, specifically relating to an antibacterial polypropylene fiber and its preparation method. Background Technology

[0002] Polypropylene resin, as one of the five major general-purpose resins, is one of the polymer materials with the largest production, consumption, and application fields in the world today. Polypropylene fiber is characterized by its lightweight, high tensile strength, and low cost. Its moisture regain is almost zero, and it has excellent hydrophobic and moisture-wicking properties. It also has good acid and alkali resistance and heat aging resistance, and can be used to prepare high-performance textiles.

[0003] However, the polypropylene molecule itself lacks polar groups and reactive sites, resulting in its inherent hydrophobicity and bioinertness, and thus it possesses no antibacterial properties. In daily use, the surface of fiber products easily accumulates sweat, skin flakes, and other bodily secretions, becoming a breeding ground for microorganisms (such as bacteria and fungi). This not only leads to odors, discoloration, degradation, and decreased mechanical properties in fiber products, but more seriously, it can become a medium for disease transmission, posing a potential threat to the health of users, especially in sensitive applications such as medical and hygiene products and intimate apparel.

[0004] Therefore, it is necessary to develop a polypropylene fiber material with excellent antibacterial effects to address the shortcomings of existing materials. Summary of the Invention

[0005] The purpose of this invention is to provide an antibacterial polypropylene fiber and its preparation method, so as to solve the problem of poor antibacterial performance of polypropylene fibers in the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention provides an antibacterial polypropylene fiber and a method for preparing the same, comprising the following raw materials by weight: Polypropylene 92-100 parts, modified chitosan 6-10 parts, zinc oxide 5-8 parts, toughening agent 3-6 parts, lubricant 1-2 parts, antioxidant 0.5-1 parts; The modified chitosan is prepared through the following steps: S1. Heat an aqueous acetic acid solution (1% by mass) to 80-85°C, add chitosan, maintain the temperature, and stir continuously until completely dissolved to obtain solution A; heat deionized water to 80-85°C (maintaining the same temperature as above), add sodium stearate, and stir until completely dissolved to obtain solution B; slowly add solution A dropwise to solution B, maintain the temperature and stir continuously for 1-1.5 hours, filter while hot, wash three times with hot ethanol, and then dry in a vacuum drying oven at 60°C for 0.5 hours to obtain amphiphilic chitosan; S2. Add amphiphilic chitosan to deionized water and stir for 3-3.5 hours. Then add carvacrol essential oil and continue stirring for 2-2.5 hours to obtain modified chitosan.

[0007] As a preferred embodiment of the present invention, the ratio of acetic acid aqueous solution, chitosan, deionized water and sodium stearate in S1 is 20g:0.95-1g:20g:0.58-0.60g.

[0008] As a preferred embodiment of the present invention, the ratio of amphiphilic chitosan, deionized water and carvacrol in S2 is 5-6g:10mL:0.1-0.2g.

[0009] In a preferred embodiment of the present invention, the zinc oxide has a particle size of 20–100 nm. When the zinc oxide particle size is small, the surface energy is high, making it prone to agglomeration into hard clusters, which become stress concentration points. This induces premature breakage and fuzzing during stretching, resulting in a decrease in fiber strength instead of an increase. When the particle size is too large, the bonding with the polypropylene interface is weak, and the sharp edges cause stress to concentrate at the tips under external force, becoming crack sources. At the same time, the melt fluidity deteriorates, melt rupture occurs in the spinneret, and the fiber diameter becomes uneven, ultimately causing a simultaneous decrease in the strength and toughness of the polypropylene fiber.

[0010] In a preferred embodiment of the present invention, the toughening agent is at least one of ethylene-vinyl acetate copolymer, polyethylene octene coelastomer, and ethylene propylene diene monomer (EPDM) rubber.

[0011] In a preferred embodiment of the present invention, the lubricant is one of calcium stearate, paraffin wax, and polyethylene wax. The purpose of adding the lubricant is to improve the fluidity of the melt, which helps the fibers to form uniformly during spinning, stretching, and other processes, reduces defects such as broken or fuzzy polypropylene fibers, and improves the continuity and surface smoothness of the polypropylene fibers.

[0012] In a preferred embodiment of the present invention, the antioxidant is at least one selected from antioxidant 1010, antioxidant 626, and antioxidant 168. The purpose of adding antioxidants is to prevent or significantly delay the degradation and aging of polypropylene resin due to oxidation reactions during high-temperature processing or use, thereby effectively extending the service life of polypropylene fibers.

[0013] A second aspect of this invention provides a method for preparing antibacterial polypropylene fibers, comprising the following steps: Step 1: Weigh out the polypropylene, modified chitosan, zinc oxide, toughening agent, lubricant and antioxidant by weight, add them to the mixer and mix evenly, then feed them into a twin-screw extruder and melt extrude to granulate to obtain masterbatch; Step 2: The dried masterbatch is melt-spun, wound into rolls, drawn and shaped to obtain antibacterial polypropylene fiber.

[0014] In a preferred embodiment of the present invention, the temperature of melt spinning in step 2 is 190-230°C, the spinning speed is 1500-2500 m / min, and the time is 0.5-3 h.

[0015] In a preferred embodiment of the present invention, the draw ratio in step 2 is 2 to 4.

[0016] The beneficial effects of this invention are: 1) This invention provides an antibacterial polypropylene fiber, composed of polypropylene, modified chitosan, zinc oxide, toughening agent, lubricant, and antioxidant. The prepared polypropylene fiber exhibits good antibacterial properties, antibacterial durability, and mechanical properties. The introduction of modified chitosan significantly enhances the antibacterial performance of the polypropylene fiber; the introduction of zinc oxide enhances the mechanical properties of the polypropylene fiber. Due to the small particle size and large specific surface area of ​​zinc oxide particles, it has a strong interfacial interaction with the polypropylene matrix, which can simultaneously improve tensile strength, elastic modulus, and impact toughness; on the other hand, zinc oxide can release Zn. 2+ It generates ROS, which, in synergy with modified chitosan, significantly improves the antibacterial properties of polypropylene fibers.

[0017] 2) This invention yields a modified chitosan. Because chitosan has poor hydrophilicity, its compatibility with the polypropylene matrix is ​​poor. Therefore, this invention utilizes the -NH3 group of chitosan... + The group combines with the -COO- group of sodium stearate to form an ionic complex, thereby grafting hydrophobic groups onto chitosan, improving the hydrophobic properties of chitosan, making chitosan amphiphilic, and thus effectively improving the compatibility of chitosan with the polypropylene matrix. Furthermore, modified chitosan is prepared by encapsulating carvacrol essential oil with antibacterial activity in amphiphilic chitosan. Carvacrol essential oil is volatile, which will cause its antibacterial ability to decrease over time during the antibacterial process, seriously affecting the antibacterial properties. Therefore, this invention can effectively improve the dispersion stability and sustained-release performance of the essential oil and prolong the antibacterial effect by encapsulating carvacrol essential oil in amphiphilic chitosan. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0019] Preparation Example

[0020] Preparation Example 1

[0021] This preparation example provides a modified chitosan, and the preparation steps are as follows: S1. Heat 20g of acetic acid aqueous solution (mass fraction 1%) to 80℃, add 0.95g of chitosan, maintain the temperature, and continue stirring until completely dissolved to obtain solution A; heat 20g of deionized water to 80℃, add 0.58g of sodium stearate, and stir until completely dissolved to obtain solution B; slowly add solution A dropwise to solution B, maintain the temperature and continue stirring for 1h, filter while hot, wash 3 times with hot ethanol, and then dry in a vacuum drying oven at 60℃ for 0.5h to obtain amphiphilic chitosan; S2. Add 5g of amphiphilic chitosan to 10mL of deionized water and stir for 3h. Then add 0.1g of carvacrol essential oil and continue stirring for 2.5h to obtain modified chitosan.

[0022] Preparation Example 2

[0023] The only difference compared to Preparation Example 1 is: S1. Heat 20g of acetic acid aqueous solution (mass fraction of 1%) to 85℃, add 1g of chitosan, maintain the temperature, and continue stirring until completely dissolved to obtain solution A; heat 20g of deionized water to 85℃, add 0.60g of sodium stearate, and stir until completely dissolved to obtain solution B; slowly add solution A dropwise to solution B, maintain the temperature and continue stirring for 1.5h, filter while hot, wash 3 times with hot ethanol, and then dry in a vacuum drying oven at 60℃ for 0.5h to obtain amphiphilic chitosan.

[0024] Preparation Example 3

[0025] The only difference compared to Preparation Example 1 is: S2. Add 6g of amphiphilic chitosan to 10mL of deionized water and stir for 3h. Then add 0.2g of carvacrol essential oil and continue stirring for 2.5h to obtain modified chitosan.

[0026] Preparation Example 4

[0027] This preparation example provides a modified chitosan, and the preparation steps are as follows: 20g of acetic acid aqueous solution (1% by mass) was heated to 80℃, and 0.95g of chitosan was added. The temperature was maintained and the mixture was stirred continuously until completely dissolved to obtain solution A. 20g of deionized water was heated to 80℃, and 0.58g of sodium stearate was added. The mixture was stirred until completely dissolved to obtain solution B. Solution A was slowly added dropwise to solution B, and the temperature was maintained and the mixture was stirred continuously for 1 hour. The mixture was filtered while hot, washed three times with hot ethanol, and then dried in a vacuum drying oven at 60℃ for 0.5 hours to obtain modified chitosan.

[0028] Example

[0029] Example 1

[0030] This embodiment provides an antibacterial polypropylene fiber and its preparation method: An antibacterial polypropylene fiber, comprising the following raw materials in parts by weight: 92 parts polypropylene, 6 parts modified chitosan from Preparation Example 1, 5 parts zinc oxide (particle size 20 nm), 3 parts ethylene-vinyl acetate copolymer, 1 part calcium stearate, and 0.5 parts antioxidant 1010.

[0031] A method for preparing antibacterial polypropylene fiber includes the following steps: Step 1: Weigh out the polypropylene, modified chitosan, zinc oxide, toughening agent, lubricant and antioxidant by weight, add them to the mixer and mix evenly, then feed them into a twin-screw extruder and melt extrude to granulate to obtain masterbatch; Step 2: The dried masterbatch is melt-spun at a temperature of 190℃, a spinning speed of 1500m / min, and a spinning time of 2.5h. The yarn is wound into rolls, drawn and shaped, with a draw ratio of 2, to obtain antibacterial polypropylene fibers.

[0032] Example 2

[0033] The only difference compared to Example 1 is: The modified chitosan in Preparation Example 1 was replaced with the modified chitosan in Preparation Example 2, with the amount of each component remaining the same.

[0034] Example 3

[0035] The only difference compared to Example 1 is: The modified chitosan in Preparation Example 1 was replaced with the modified chitosan in Preparation Example 3, with the amount of each component remaining the same.

[0036] Example 4

[0037] The only difference compared to Example 1 is: Replace the 20nm zinc oxide with the 60nm zinc oxide, keeping the amount the same.

[0038] Example 5

[0039] The only difference compared to Example 1 is: Replace the 20nm zinc oxide with 100nm zinc oxide, keeping the amount the same.

[0040] Example 6

[0041] The only difference compared to Example 1 is: An antibacterial polypropylene fiber, comprising the following raw materials in parts by weight: 96 parts polypropylene, 8 parts modified chitosan from Preparation Example 1, 7 parts zinc oxide (particle size 20 nm), 4.5 parts ethylene-vinyl acetate copolymer, 1.5 parts calcium stearate, and 0.7 parts antioxidant 1010.

[0042] Example 7

[0043] The only difference compared to Example 1 is: An antibacterial polypropylene fiber, comprising the following raw materials in parts by weight: 100 parts polypropylene, 10 parts modified chitosan from Preparation Example 1, 8 parts zinc oxide (particle size 20 nm), 6 parts ethylene-vinyl acetate copolymer, 2 parts calcium stearate, and 1 part antioxidant 1010. Example 8 The only difference compared to Example 1 is: Step 2: The dried masterbatch is melt-spun at a temperature of 220℃, a spinning speed of 2480m / min, and a spinning time of 1.5h. The yarn is wound into rolls, drawn and shaped, with a draw ratio of 2, to obtain antibacterial polypropylene fibers.

[0044] Example 9

[0045] The only difference compared to Example 1 is: Step 2: The dried masterbatch is melt-spun at a temperature of 190℃, a spinning speed of 1500m / min, and a spinning time of 2.5h. The yarn is wound into rolls, drawn and shaped, with a draw ratio of 4, to obtain antibacterial polypropylene fibers.

[0046] Comparative Example

[0047] Comparative Example 1

[0048] This comparative example provides an antibacterial polypropylene fiber and its preparation method: An antibacterial polypropylene fiber, comprising the following raw materials in parts by weight: 92 parts polypropylene, 6 parts chitosan, 5 parts zinc oxide (particle size 20nm), 3 parts ethylene-vinyl acetate copolymer, 1 part calcium stearate, and 0.5 parts antioxidant 1010.

[0049] A method for preparing antibacterial polypropylene fiber includes the following steps: Step 1: Weigh out the polypropylene, modified chitosan, zinc oxide, toughening agent, lubricant and antioxidant by weight, add them to the mixer and mix evenly, then feed them into a twin-screw extruder and melt extrude to granulate to obtain masterbatch; Step 2: The dried masterbatch is melt-spun at a temperature of 190℃, a spinning speed of 1500m / min, and a spinning time of 2.5h. The yarn is wound into rolls, drawn and shaped, with a draw ratio of 2, to obtain antibacterial polypropylene fibers.

[0050] Comparative Example 2

[0051] The only difference compared to Example 1 is: The modified chitosan in Preparation Example 1 was replaced with the modified chitosan in Preparation Example 4, with the amount of each component remaining the same.

[0052] Comparative Example 3

[0053] The only difference compared to Example 1 is: The 6 parts of modified chitosan in Preparation Example 1 were replaced with 4 parts of modified chitosan in Preparation Example 1.

[0054] Comparative Example 4

[0055] The only difference compared to Example 7 is: The 10 parts of modified chitosan in Preparation Example 1 were replaced with 13 parts of modified chitosan in Preparation Example 1.

[0056] Comparative Example 5

[0057] The only difference compared to Example 7 is: An antibacterial polypropylene fiber, comprising the following raw materials in parts by weight: 92 parts polypropylene, 6 parts modified chitosan from Preparation Example 1, 3 parts ethylene-vinyl acetate copolymer, 1 part calcium stearate, and 0.5 parts antioxidant 1010.

[0058] Comparative Example 6

[0059] The only difference compared to Example 1 is: Replace the 20nm zinc oxide with 10nm zinc oxide, keeping the amount the same.

[0060] Comparative Example 7

[0061] The only difference compared to Example 5 is: Replace the 100nm zinc oxide with the 115nm zinc oxide, keeping the amount the same.

[0062] Comparative Example 8

[0063] The only difference compared to Example 1 is: An antibacterial polypropylene fiber, comprising the following raw materials in parts by weight: 80 parts polypropylene, 6 parts modified chitosan from Preparation Example 1, 5 parts zinc oxide (particle size 20nm), 3 parts ethylene-vinyl acetate copolymer, 1 part calcium stearate, and 0.5 parts antioxidant 1010.

[0064] Comparative Example 9

[0065] The only difference compared to Example 1 is: An antibacterial polypropylene fiber, comprising the following raw materials in parts by weight: 80 parts polypropylene, 6 parts modified chitosan from Preparation Example 1, 5 parts zinc oxide (particle size 20 nm), 3 parts ethylene-vinyl acetate copolymer, and 0.2 parts antioxidant 1010.

[0066] Comparative Example 10

[0067] The only difference compared to Example 1 is: Step 2: The dried masterbatch is melt-spun at a temperature of 190℃, a spinning speed of 1500m / min, and a spinning time of 2.5h. The yarn is wound into rolls, drawn and shaped, with a draw ratio of 2, to obtain antibacterial polypropylene fibers.

[0068] Comparative Example 11

[0069] The only difference compared to Example 1 is: Step 2: The dried masterbatch is melt-spun at a temperature of 190℃, a spinning speed of 1500m / min, and a spinning time of 2.5h. The yarn is wound into rolls, drawn and shaped, with a draw ratio of 2, to obtain antibacterial polypropylene fibers.

[0070] Performance testing

[0071] The antibacterial polypropylene fibers obtained in Examples 1 to 9 and Comparative Examples 1 to 11 were subjected to the following performance tests: 1) Mechanical properties: Referring to GB / T 14344-2008 "Test Method for Tensile Properties of Chemical Fiber Filaments", the breaking strength and initial modulus of the test samples were tested at 25℃ using a YG(B)021H type electronic tensile testing machine for chemical fiber filaments produced by Wenzhou Darong Textile Instrument Co., Ltd.

[0072] 2) Antibacterial properties: Refer to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", and select Staphylococcus aureus and Escherichia coli as the bacterial strains.

[0073] 3) Wash resistance: After the sample is washed 50 times according to standard, its antibacterial properties are tested and the changes in antibacterial properties are compared.

[0074] The test results are shown in Table 1: Table 1

[0075] As shown in Table 1, compared with Comparative Examples 1-11, the antibacterial polypropylene fibers prepared in Examples 1-9 exhibit superior antibacterial properties, mechanical properties, and wash resistance. Therefore, the antibacterial polypropylene fiber and its preparation method provided by this invention produce polypropylene fibers with good antibacterial properties, long-lasting antibacterial activity, and mechanical properties.

[0076] Combining Comparative Examples 1-3 with Examples 1, 4, and 7, it can be seen that the chitosan added in Comparative Example 1 was unmodified, the chitosan added in Comparative Example 2 was the chitosan obtained in Preparation Example 4, i.e., only hydrophobically modified, without carvacrol oil coating, and the modified chitosan added in Comparative Examples 3-4 all exceeded the scope defined by this invention. Based on the data in Table 1, it can be seen that the hydrophobically modified chitosan and carvacrol oil-coated chitosan have superior antibacterial properties, resulting in excellent antibacterial properties in the polypropylene fibers. Furthermore, the antibacterial properties of the polypropylene fibers obtained in Comparative Examples 1-2 significantly decreased after washing. Therefore, the modified chitosan provided by this invention has excellent antibacterial sustained-release effect and can effectively prolong the antibacterial effect. In addition, combining Comparative Examples 3 with Examples 1, 4, and 7, it can be seen that the amount of modified chitosan also affects the antibacterial effect of the polypropylene fibers.

[0077] By combining Comparative Examples 5-6 with Example 1, and Comparative Examples 7 with Example 5, it can be seen that no zinc oxide was added in Comparative Example 5, and the particle size of zinc oxide in Comparative Examples 6-7 all exceeded the range of zinc oxide particle size defined in this invention. Furthermore, by combining the data in Table 1, it can be seen that both the amount of zinc oxide and the particle size will affect the mechanical properties of polypropylene fibers.

[0078] As can be seen from Comparative Examples 8-11 and Example 1, the differences in raw materials and preparation processes of polypropylene fibers can affect fiber properties and antibacterial properties.

[0079] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0080] 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. An antibacterial polypropylene fiber, characterized in that, By weight, it includes the following ingredients: Polypropylene 92-100 parts, modified chitosan 6-10 parts, zinc oxide 5-8 parts, toughening agent 3-6 parts, lubricant 1-2 parts, antioxidant 0.5-1 parts; The modified chitosan is prepared through the following steps: S1. After heating the aqueous acetic acid solution to 80-85℃, add chitosan, maintain the temperature, and continue stirring until completely dissolved to obtain solution A; after heating deionized water to 80-85℃, add sodium stearate and stir until completely dissolved to obtain solution B; slowly add solution A dropwise to solution B, maintain the temperature and continue stirring for 1-1.5 hours, filter while hot, wash, and vacuum dry to obtain amphiphilic chitosan; S2. Add amphiphilic chitosan to deionized water and stir for 3-3.5 hours. Then add carvacrol essential oil and continue stirring for 2-2.5 hours to obtain modified chitosan.

2. The antibacterial polypropylene fiber according to claim 1, characterized in that, The ratio of acetic acid aqueous solution, chitosan, deionized water and sodium stearate in S1 is 20g:0.95~1g:20g:0.58~0.60g.

3. The antibacterial polypropylene fiber according to claim 1, characterized in that, The ratio of amphiphilic chitosan, deionized water, and carvacrol in S2 is 5–6 g: 10 mL: 0.1–0.2 g.

4. The antibacterial polypropylene fiber according to claim 1, characterized in that, The zinc oxide has a particle size of 20–100 nm.

5. The antibacterial polypropylene fiber according to claim 1, characterized in that, The toughening agent is at least one of ethylene-vinyl acetate copolymer, polyethylene octene copolymer, and ethylene propylene diene monomer (EPDM) rubber.

6. The antibacterial polypropylene fiber according to claim 1, characterized in that, The lubricant is one of calcium stearate, paraffin wax, and polyethylene wax.

7. The antibacterial polypropylene fiber according to claim 1, characterized in that, The antioxidant is at least one of antioxidant 1010, antioxidant 626 and antioxidant 168.

8. The method for preparing antibacterial polypropylene fiber according to claim 1, characterized in that, Includes the following steps: Step 1: Weigh out the polypropylene, modified chitosan, zinc oxide, toughening agent, lubricant and antioxidant by weight, add them to the mixer and mix evenly, then feed them into a twin-screw extruder and melt extrude to granulate to obtain masterbatch; Step 2: The dried masterbatch is melt-spun, wound into rolls, drawn and shaped to obtain antibacterial polypropylene fiber.

9. The method for preparing antibacterial polypropylene fiber according to claim 8, characterized in that, In step 2, the melt spinning temperature is 190–230℃, the spinning speed is 1500–2500 m / min, and the time is 0.5–3 h.

10. The method for preparing antibacterial polypropylene fiber according to claim 8, characterized in that, The draw ratio in step 2 is 2 to 4.

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