Antibacterial and flame-retardant PE-PET composite fiber and preparation method thereof

Abstract

The application relates to the technical field of high polymer materials, and discloses an antibacterial and flame-retardant PE-PET composite fiber and a preparation method thereof. The antibacterial and flame-retardant PE-PET composite fiber is mainly prepared from polyethylene, modified polyethylene and polyethylene terephthalate as raw materials. The application prepares modified polyethylene, the polar structure contained in the modified polyethylene and other polar structures produce chemical linkage with each other, the degree of chemical crosslinking is increased, the mechanical properties of the composite fiber are increased, the flame-retardant structure and the antibacterial structure contained in the modified polyethylene increase the flame-retardant properties and the antibacterial properties of the composite fiber.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an antibacterial and flame-retardant PE-PET composite fiber and its preparation method. Background Technology

[0002] With the rapid development of the global textile industry and the increasing awareness of safety and health among the public, the functional requirements for textiles have long surpassed basic warmth and aesthetics. High-performance fibers with both antibacterial and flame-retardant properties have become a research hotspot and market demand direction in fields such as industrial textiles, home textiles, and specialty clothing.

[0003] Polyethylene-polyethylene terephthalate (PE-PET) composite fibers are widely used in artificial leather, high-end wiping cloths, and filter materials due to their excellent softness, high specific surface area, and strong adsorption capacity. However, both PE and PET are flammable polymers and lack the ability to inhibit microbial growth, which greatly limits their application in scenarios with strict safety and hygiene requirements, such as medical protective equipment, hotel and home furnishings, and vehicle interiors. Therefore, developing PE-PET composite fibers that combine highly efficient antibacterial and long-lasting flame retardant functions has significant practical and technological value. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides an antibacterial and flame-retardant PE-PET composite fiber and its preparation method. The prepared composite fiber exhibits excellent antibacterial, flame-retardant, and mechanical properties.

[0006] (II) Technical Solution

[0007] An antibacterial and flame-retardant PE-PET composite fiber, wherein the antibacterial and flame-retardant PE-PET composite fiber is prepared from polyethylene, modified polyethylene, and polyethylene terephthalate as raw materials;

[0008] The preparation method of the antibacterial and flame-retardant PE-PET composite fiber includes the following steps:

[0009] S1. Under nitrogen protection, the cleaned polyethylene powder was added to xylene solvent and stirred to disperse. Benzoyl peroxide was then added, and maleic anhydride and target product 3 were added at 75-80℃ with stirring. The reaction was stirred for 4-6 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, extracted with propanol, and dried to obtain modified polyethylene. Under the initiation of benzoyl peroxide, maleic anhydride and target product 3 were grafted into polyethylene using the polyene structure contained in target product 3 and the alkenyl structure contained in maleic anhydride. This not only introduced polar structures into polyethylene but also formed a multi-crosslinked network structure (which was formed by using the hexamene group contained in target product 3 to initiate grafting into polyethylene). Not only a physical crosslinked structure (multi-crosslinked network structure) was formed but also a chemical crosslinked structure (hydrogen bonds were formed between polar structures). Since target product 3 also contains heat-resistant Schiff base structure, benzene ring structure and phosphazene structure, it can improve the heat resistance of polyethylene and make up for the defect of poor heat resistance of polyethylene.

[0010] S2. Modified polyethylene and polyethylene are stirred and mixed evenly, and dried polyethylene terephthalate (PET) are placed in a screw extruder for melt extrusion. The mixture is then drawn and spun through a melt spinning machine and wound and shaped through a winding machine to obtain antibacterial and flame-retardant PE-PET composite fibers. In this process, ordinary polyethylene itself has a non-polar structure, while PET has a polar structure. The two have poor compatibility, and direct spinning results in poor spinnability. This invention utilizes the polyethylene segments and polar structure contained in modified polyethylene (the polyethylene segments in modified polyethylene have good compatibility with polyethylene, and the polar structure in it can form hydrogen bonds with the polar structure in PET, i.e., chemical linkage) to increase the compatibility of PE and PET, thereby increasing the interfacial compatibility of the PE and PET phases, increasing spinnability, and thus increasing the comprehensive performance of the composite fiber.

[0011] Preferably, in S1, the mass ratio of polyethylene powder, benzoyl peroxide, maleic anhydride, and target product 3 is 100:1-2:2-4:1-3.

[0012] Preferably, in S2, the mass ratio of modified polyethylene, polyethylene, and polyethylene terephthalate is 1-5:100:100.

[0013] Preferably, the preparation method of the target product 3 includes the following steps:

[0014] SS1. Under nitrogen protection, hexachlorocyclotriphosphazene was added to tetrahydrofuran solvent and stirred thoroughly to dissolve. Then, 4-mercaptobenzaldehyde was slowly added and stirred for 30-40 minutes. An acid-binding agent was then added, and the mixture was refluxed for 20-24 hours. After the reaction was complete, the mixture was filtered, rotary evaporated, and then n-heptane was added, stirred, filtered, and dried to obtain target product 1. The molar ratio of hexachlorocyclotriphosphazene, 4-mercaptobenzaldehyde, and the acid-binding agent was 1:7-7.5:7.5-8.5. In this reaction, hexachlorocyclotriphosphazene and 4-mercaptobenzaldehyde were used as the main raw materials. Target product 1 was obtained through a nucleophilic substitution reaction, introducing an active aldehyde group into target product 1 to facilitate subsequent reactions. The reaction process is as follows:

[0015] ;

[0016] SS2. Under nitrogen protection, target product 1 was added to anhydrous methanol solvent and ultrasonically dispersed. Then, under stirring in a 55°C water bath, N,N-dimethyl-1,3-propanediamine was added, and the mixture was refluxed for 4-6 hours. After the reaction, the mixture was allowed to stand, filtered, recrystallized from methanol, and dried to obtain target product 2. The molar ratio of target product 1 to N,N-dimethyl-1,3-propanediamine was 1:6.5-7. In this reaction, the aldehyde group in target product 1 reacted with the amino group in N,N-dimethyl-1,3-propanediamine to form a Schiff base, thus introducing not only a Schiff base structure but also a tertiary amine structure. The reaction process is as follows:

[0017] ;

[0018] SS3. Under nitrogen protection, target product 2 and chloroolefin were added to anhydrous ethanol solvent, stirred and mixed evenly, heated to 40-50℃, and reacted for 20-24 hours. After the reaction was completed, the mixture was distilled under reduced pressure, recrystallized, and dried to obtain target product 3. The molar ratio of target product 2 to chloroolefin was 1:6-7. In this reaction, the tertiary amine structure contained in target product 2 was used to quaternize with chloroolefin to obtain target product 3. Target product 3 not only introduced an antibacterial quaternary ammonium salt structure but also contained an active alkenyl structure to facilitate the subsequent reaction. The reaction process is as follows:

[0019] ,in , n=1-4.

[0020] Preferably, in SS1, the acid-binding agent is one of sodium hydroxide and triethylamine.

[0021] Preferably, in SS3, the chloroolefin is one of 3-chloropropene, 4-chlorobutene, 5-chloropentene, and 6-chlorohexene.

[0022] (iii) Beneficial technical effects

[0023] The target product 3 prepared by this invention contains a flame-retardant structure - phosphazene structure. When heated, it decomposes to produce phosphoric acid, metaphosphoric acid, and polyphosphoric acid, which form a non-volatile protective film on the surface of the matrix material, isolating it from air. When heated, it also produces inert gases. These non-flammable gases hinder the supply of oxygen. At the same time, the sulfur element contained therein can produce non-flammable gases such as sulfur dioxide when heated, diluting the concentration of flammable gases and achieving a synergistic effect of flame retardancy.

[0024] The target product 3 prepared by this invention not only contains a flame-retardant structure—a phosphazene structure—but also an antibacterial multi-quaternary ammonium salt structure and a multi-Schiff base structure. The antibacterial structure, possessing two antibacterial mechanisms, synergistically enhances the antibacterial properties of the matrix material. Furthermore, the target product 3 prepared by this invention also contains a polyene structure and a polar structure. The polyene structure, under the initiation of an initiator, is grafted into polyethylene, increasing the crosslinking density of polyethylene. The polar structure can chemically link with the polar bonds in PET, not only enhancing the interfacial compatibility between polyethylene and PET but also generating a chemically crosslinked network structure, further improving the overall performance of the composite fiber. Detailed Implementation

[0025] The present invention will be further described in detail below through specific embodiments.

[0026] Example 1

[0027] S1. Under nitrogen protection, 50 mmol of hexachlorocyclotriphosphazene was added to tetrahydrofuran solvent and stirred thoroughly to dissolve. Then, 350 mmol of 4-mercaptobenzaldehyde was slowly added and stirred for 35 min. Then, 375 mmol of sodium hydroxide acid-binding agent was added and the mixture was refluxed for 24 h. After the reaction was completed, the mixture was filtered, rotary evaporated, and then n-heptane was added. The mixture was stirred and mixed, filtered, and dried to obtain target product 1.

[0028] S2. Under nitrogen protection, 40 mmol of target product 1 was added to anhydrous methanol solvent and ultrasonically dispersed. Under stirring in a water bath at 55°C, 280 mmol of N,N-dimethyl-1,3-propanediamine was added and the mixture was refluxed for 4 h. After the reaction was completed, the mixture was allowed to stand, filtered, recrystallized from methanol, and dried to obtain target product 2.

[0029] S3. Under nitrogen protection, 20 mmol of target product 2 and 120 mmol of 3-chloropropene were added to anhydrous ethanol solvent, stirred and mixed evenly, heated to 50°C, and kept at the temperature for 20 h. After the reaction was completed, the product was distilled under reduced pressure, recrystallized, and dried to obtain target product 3.

[0030] S4. Under nitrogen protection, 100 parts by weight of the cleaned polyethylene powder were added to xylene solvent and stirred to disperse. Then, 1 part of benzoyl peroxide was added, and 2 parts of maleic anhydride and 1 part of target product 3 were added at 80°C with stirring. The mixture was stirred and reacted for 6 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, extracted with propanol, and dried to obtain modified polyethylene.

[0031] S5. By weight, 1 part by weight of modified polyethylene and 100 parts by weight of polyethylene are stirred and mixed evenly, and then mixed with 100 parts by weight of dried polyethylene terephthalate. The mixture is then melt-extruded in a screw extruder. The screw temperatures of the modified polyethylene and polyethylene in the screw extruder are 210℃, 220℃, 230℃, 240℃, and 245℃, respectively. The screw temperatures of the polyethylene terephthalate in the screw extruder are 275℃, 280℃, 285℃, 290℃, and 295℃, respectively. The screw speed is 300 r / min for all of them. The mixture is then drawn and spun through a melt spinning machine at a spinning temperature of 285℃ and a drawing speed of 1000 m / min. Finally, it is wound and shaped by a winding machine to obtain antibacterial and flame-retardant PE-PET composite fiber.

[0032] Example 2

[0033] S1. Under nitrogen protection, 50 mmol of hexachlorocyclotriphosphazene was added to tetrahydrofuran solvent and stirred thoroughly to dissolve. Then, 360 mmol of 4-mercaptobenzaldehyde was slowly added and stirred for 40 min. Then, 400 mmol of sodium hydroxide acid-binding agent was added and the mixture was refluxed for 20 h. After the reaction was completed, the mixture was filtered, rotary evaporated, and then n-heptane was added. The mixture was stirred and mixed, filtered, and dried to obtain target product 1.

[0034] S2. Under nitrogen protection, 40 mmol of target product 1 was added to anhydrous methanol solvent and ultrasonically dispersed. Under stirring in a water bath at 55°C, 280 mmol of N,N-dimethyl-1,3-propanediamine was added and the mixture was refluxed for 4 h. After the reaction was completed, the mixture was allowed to stand, filtered, recrystallized from methanol, and dried to obtain target product 2.

[0035] S3. Under nitrogen protection, 20 mmol of target product 2 and 140 mmol of 4-chlorobutene were added to anhydrous ethanol solvent, stirred and mixed evenly, heated to 40°C, and kept at the temperature for 24 h. After the reaction was completed, the product was distilled under reduced pressure, recrystallized, and dried to obtain target product 3.

[0036] S4. Under nitrogen protection, 100 parts by weight of the cleaned polyethylene powder were added to xylene solvent and stirred to disperse. Then, 2 parts of benzoyl peroxide were added, and 3 parts of maleic anhydride and 2 parts of target product 3 were added at 75°C with stirring. The mixture was stirred and reacted for 5 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, extracted with propanol, and dried to obtain modified polyethylene.

[0037] S5. By weight, 2 parts of modified polyethylene and 100 parts of polyethylene are stirred and mixed evenly, and then mixed with 100 parts of dried polyethylene terephthalate. The mixture is then melt-extruded in a screw extruder. The screw temperatures of the modified polyethylene and polyethylene in the screw extruder are 210℃, 220℃, 230℃, 240℃, and 245℃, respectively. The screw temperatures of the polyethylene terephthalate in the screw extruder are 275℃, 280℃, 285℃, 290℃, and 295℃, respectively. The screw speed is 300 r / min for all parts. The mixture is then drawn and spun through a melt spinning machine at a spinning temperature of 285℃ and a drawing speed of 1000 m / min. Finally, it is wound and shaped by a winding machine to obtain antibacterial and flame-retardant PE-PET composite fiber.

[0038] Example 3

[0039] S1. Under nitrogen protection, 50 mmol of hexachlorocyclotriphosphazene was added to tetrahydrofuran solvent and stirred thoroughly to dissolve. Then, 375 mmol of 4-mercaptobenzaldehyde was slowly added and stirred for 30 min. Then, 425 mmol of sodium hydroxide acid-binding agent was added and the mixture was refluxed for 22 h. After the reaction was completed, the mixture was filtered, rotary evaporated, and then n-heptane was added. The mixture was stirred and mixed, filtered, and dried to obtain target product 1.

[0040] S2. Under nitrogen protection, 40 mmol of target product 1 was added to anhydrous methanol solvent and ultrasonically dispersed. Under stirring in a water bath at 55°C, 270 mmol of N,N-dimethyl-1,3-propanediamine was added and the mixture was refluxed for 4 h. After the reaction was completed, the mixture was allowed to stand, filtered, recrystallized from methanol, and dried to obtain target product 2.

[0041] S3. Under nitrogen protection, 20 mmol of target product 2 and 130 mmol of 5-chloropentene were added to anhydrous ethanol solvent, stirred and mixed evenly, heated to 45°C, and kept at the temperature for 22 h. After the reaction was completed, the product was distilled under reduced pressure, recrystallized, and dried to obtain target product 3.

[0042] S4. Under nitrogen protection, 100 parts by weight of the cleaned polyethylene powder were added to xylene solvent and stirred to disperse. Then, 2 parts of benzoyl peroxide were added, and 4 parts of maleic anhydride and 3 parts of target product 3 were added at 80°C with stirring. The mixture was stirred and reacted for 4 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, extracted with propanol, and dried to obtain modified polyethylene.

[0043] S5. By weight, 4 parts of modified polyethylene and 100 parts of polyethylene are stirred and mixed evenly, and then mixed with 100 parts of dried polyethylene terephthalate. The mixture is then melt-extruded in a screw extruder. The screw temperatures of the modified polyethylene and polyethylene in the screw extruder are 210℃, 220℃, 230℃, 240℃, and 245℃, respectively. The screw temperatures of the polyethylene terephthalate in the screw extruder are 275℃, 280℃, 285℃, 290℃, and 295℃, respectively. The screw speed is 300 r / min for all parts. The mixture is then drawn and spun through a melt spinning machine at a spinning temperature of 285℃ and a drawing speed of 1000 m / min. Finally, it is wound and shaped by a winding machine to obtain antibacterial and flame-retardant PE-PET composite fiber.

[0044] Example 4

[0045] S1. Under nitrogen protection, 50 mmol of hexachlorocyclotriphosphazene was added to tetrahydrofuran solvent and stirred thoroughly to dissolve. Then, 375 mmol of 4-mercaptobenzaldehyde was slowly added and stirred for 40 min. Then, 420 mmol of sodium hydroxide acid-binding agent was added and the mixture was refluxed for 24 h. After the reaction was completed, the mixture was filtered, rotary evaporated, and then n-heptane was added. The mixture was stirred and mixed, filtered, and dried to obtain target product 1.

[0046] S2. Under nitrogen protection, 40 mmol of target product 1 was added to anhydrous methanol solvent and ultrasonically dispersed. Under stirring in a water bath at 55°C, 260 mmol of N,N-dimethyl-1,3-propanediamine was added and the mixture was refluxed for 6 h. After the reaction was completed, the mixture was allowed to stand, filtered, recrystallized from methanol, and dried to obtain target product 2.

[0047] S3. Under nitrogen protection, 20 mmol of target product 2 and 130 mmol of 6-chlorohexene were added to anhydrous ethanol solvent, stirred and mixed evenly, heated to 45°C, and kept at the temperature for 24 h. After the reaction was completed, the product was distilled under reduced pressure, recrystallized, and dried to obtain target product 3.

[0048] S4. Under nitrogen protection, 100 parts by weight of the cleaned polyethylene powder were added to xylene solvent and stirred to disperse. Then, 2 parts of benzoyl peroxide were added, and 2 parts of maleic anhydride and 3 parts of target product 3 were added at 75°C with stirring. The mixture was stirred and reacted for 6 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, extracted with propanol, and dried to obtain modified polyethylene.

[0049] S5. By weight, 5 parts of modified polyethylene and 100 parts of polyethylene are stirred and mixed evenly, and then mixed with 100 parts of dried polyethylene terephthalate. The mixture is then melt-extruded in a screw extruder. The screw temperatures of the modified polyethylene and polyethylene in the screw extruder are 210℃, 220℃, 230℃, 240℃, and 245℃, respectively. The screw temperatures of the polyethylene terephthalate in the screw extruder are 275℃, 280℃, 285℃, 290℃, and 295℃, respectively. The screw speed is 300 r / min for all of them. The mixture is then drawn and spun through a melt spinning machine at a spinning temperature of 285℃ and a drawing speed of 1000 m / min. Finally, it is wound and shaped by a winding machine to obtain antibacterial and flame-retardant PE-PET composite fiber.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that in step 4, target product 2 is used instead of target product 3.

[0052] Comparative Example 2

[0053] The difference between this comparative example and Example 1 is that in step 4, a commercially available quaternary ammonium salt antibacterial agent is used instead of the target product 3.

[0054] The tensile strength of the composite fiber was tested in accordance with GB / T 14337-2008.

[0055] The LOI value of the composite fiber was tested according to GB / T5454-1997.

[0056] Table 1:

[0057]

[0058] As shown in Table 1, the mechanical and flame-retardant properties of the present invention are good. The required tensile strength should be ≥2.60 cN / dtex. The target product 3 contained in Examples 1-4 has a high degree of crosslinking and compatibility. Therefore, the tensile strength of Examples 1-4 is ≥2.60 cN / dtex. Comparative Examples 1-2, which do not contain the target product 3, have poor tensile strength and do not meet the requirements. The reason why the mechanical properties of Comparative Example 1 are better than those of Comparative Example 2 may be that Comparative Example 1 contains the target product 2, which has more branched structures. Although it cannot be grafted into polyethylene, it can produce more physical crosslinked network structures due to its numerous branched structures. Therefore, when subjected to external force, it can be dispersed into other molecular chains through the crosslinked network structure, thereby improving the mechanical properties. Therefore, the mechanical properties of Comparative Example 1 are better than those of Comparative Example 2. In addition, Examples 1-4 and Comparative Example 1, which contain phosphazene structures, have excellent flame-retardant properties, while those without phosphazene structures have poor flame-retardant properties.

[0059] According to the AATCC100-2004 standard "Performance Evaluation of Antibacterial Finishing of Textile Materials", the composite fibers produced by the method of this invention were woven into fabrics and then tested. The test strain was Escherichia coli. The fabrics were washed 100 times and then the antibacterial rate was tested.

[0060] Table 2:

[0061]

[0062] As shown in Table 2, the composite fiber prepared by the present invention has excellent long-term antibacterial properties. This is because the target product 3 prepared by the present invention is grafted onto the main chain of polyethylene molecules, which confines the antibacterial structure to the cross-linked network structure. It can still have good antibacterial properties after water washing. Ordinary quaternary ammonium salt antibacterial agents are added to it, and after water washing, they are lost, and their antibacterial properties decrease, which is not conducive to long-term antibacterial properties.

[0063] In summary, the composite fiber prepared by this invention has excellent mechanical properties, antibacterial properties, and flame retardant properties, and can be widely used in textiles.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An antibacterial and flame-retardant PE-PET composite fiber, characterized in that, The antibacterial and flame-retardant PE-PET composite fiber is mainly prepared from polyethylene, modified polyethylene, and polyethylene terephthalate as raw materials. The preparation method of the antibacterial and flame-retardant PE-PET composite fiber includes the following steps: S1. Under nitrogen protection, the cleaned polyethylene powder is added to xylene solvent and stirred to disperse. Benzoyl peroxide is then added to the mixture. Maleic anhydride and target product 3 are added at 75-80℃ with stirring. The mixture is stirred and reacted for 4-6 hours. After the reaction is completed, the mixture is filtered, washed with ethanol, extracted with propanol, and dried to obtain modified polyethylene. S2. Modified polyethylene and polyethylene are mixed evenly and then placed in a screw extruder and melt-extruded with dried polyethylene terephthalate. The mixture is then drawn and spun through a melt spinning machine and wound and shaped through a winding machine to obtain antibacterial and flame-retardant PE-PET composite fiber. The preparation method of the target product 3 includes the following steps: SS1. Under nitrogen protection, hexachlorocyclotriphosphazene was added to tetrahydrofuran solvent and stirred thoroughly to dissolve. Then, 4-mercaptobenzaldehyde was slowly added and stirred for 30-40 min. Then, an acid-binding agent was added and the mixture was refluxed for 20-24 h. After the reaction was completed, the mixture was filtered, rotary evaporated, and then n-heptane was added, stirred and mixed, filtered, and dried to obtain target product 1. The acid-binding agent is one of sodium hydroxide and triethylamine. SS2. Under nitrogen protection, target product 1 was added to anhydrous methanol solvent and ultrasonically dispersed. N,N-dimethyl-1,3-propanediamine was added under stirring in a water bath at 55°C. The mixture was refluxed for 4-6 hours. After the reaction was completed, the mixture was allowed to stand, filtered, recrystallized from methanol, and dried to obtain target product 2. SS3. Under nitrogen protection, target product 2 and chloroolefin are added to anhydrous ethanol solvent, stirred and mixed evenly, heated to 40-50℃, and reacted for 20-24 hours. After the reaction is completed, the product is distilled under reduced pressure, recrystallized, and dried to obtain target product 3. The chloroolefin is one of 3-chloropropene, 4-chlorobutene, 5-chloropentene, and 6-chlorohexene.

2. The antibacterial and flame-retardant PE-PET composite fiber according to claim 1, characterized in that, In S1, the mass ratio of polyethylene powder, benzoyl peroxide, maleic anhydride, and target product 3 is 100:1-2:2-4:1-3.

3. The antibacterial and flame-retardant PE-PET composite fiber according to claim 1, characterized in that, In S2, the mass ratio of modified polyethylene, polyethylene, and polyethylene terephthalate is 1-5:100:

100.

4. The antibacterial and flame-retardant PE-PET composite fiber according to claim 1, characterized in that, In SS1, the molar ratio of hexachlorocyclotriphosphazene, 4-mercaptobenzaldehyde, and acid-binding agent is 1:7-7.5:7.5-8.

5.

5. The antibacterial and flame-retardant PE-PET composite fiber according to claim 1, characterized in that, In SS2, the molar ratio of target product 1 to N,N-dimethyl-1,3-propanediamine is 1:6.5-7.

6. The antibacterial and flame-retardant PE-PET composite fiber according to claim 1, characterized in that, In SS3, the molar ratio of target product 2 to chloroolefin is 1:6-7.

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