PET white copper antibacterial master batch as well as preparation method and application thereof

Abstract

The invention relates to a PET white copper antibacterial master batch as well as a preparation method and application thereof. The master batch takes PET as a matrix, is compounded with a zirconium phosphate copper-loaded antibacterial agent and a titanium dioxide white system, is matched with an antioxidant, a heat stabilizer and a lubricating and dispersing aid, and is obtained by premixing, melting, blending, extruding and granulating; a reactive chain extender / compatilizer containing an epoxy functional group and / or an oxazoline functional group can be added into the master batch and reacts with a PET end group in the processing process to realize chain extension and end capping and form a long-chain branch / light branched structure, so that the melt viscosity and the processing stability are improved, the wetting coating and dispersion stability of antibacterial particles and pigments is enhanced, and the antibacterial property of the antibacterial particles and the pigments is improved. Chromatic aberration and yellowing are reduced, and filtering pressure rise is slowed down. The obtained master batch is used for preparing white antibacterial fibers and products by blending spinning or molding with PET slices, and has the characteristics of good antibacterial effect, high appearance consistency and excellent durability and processability.

Description

Technical Field

[0001] This invention relates to a white copper antibacterial masterbatch for PET, its preparation method and application, belonging to the field of polymer masterbatch technology. Background Technology

[0002] The research and application of antimicrobial materials are receiving increasing attention, especially in industries such as food packaging, medical devices, and household goods. Antimicrobial plastic materials can effectively inhibit the spread of bacteria and viruses, improving product safety and lifespan. However, traditional antimicrobial masterbatches typically use metal ions such as silver and copper as active ingredients. While these offer good antimicrobial effects, they often cause color variations when used in white masterbatches, affecting appearance quality. Therefore, how to maintain good antimicrobial performance while avoiding color variations has become a pressing problem in the current technological field.

[0003] Metal ion-based inorganic antibacterial agents primarily act on the bacterial cell wall and cell membrane. The cell wall, located on the outermost layer of the bacterial cell, surrounds the cell membrane, forming a complex, tough, and elastic mesh structure that can withstand the strong intracellular osmotic pressure without being damaged, providing support and protection. The cell membrane is an elastic, semi-permeable membrane whose outer side is in direct contact with the external environment. Its main functions include selectively exchanging, absorbing, and transporting substances, recognizing and transmitting information. When the cell wall or cell membrane is damaged, the exchange of substances between the inside and outside of the cell is affected, leading to leakage of intracellular substances and ultimately bacterial death. Copper is an abundant and inexpensive transition metal, and all copper compounds are soluble. Copper that enters the human body can also be excreted through metabolism. Furthermore, copper is the third most abundant element in the human body after iron and zinc, making it a vital element. Furthermore, copper is an important raw material for hematopoiesis. Copper plays a vital role in the metabolism of connective tissues such as human skin and cartilage, catalyzing the synthesis of hemoglobin and participating in the hematopoietic process. Therefore, copper-containing textiles can enhance the healing speed of skin growth factors. Thus, using copper instead of silver to make antibacterial functional textiles has become a formula and popular trend in the industry. Moreover, copper-containing antibacterial components in PET melt easily form migratory free copper ions and active sites on the particle surface. Under conditions of high temperature, shear, and trace amounts of water / oxygen, free copper ions can easily promote the thermal oxidation reaction of PET and induce end-group growth, leading to decreased intrinsic viscosity, increased yellowing / color difference, and deteriorated processing stability such as melt fluctuation and accelerated filter pressure rise. This is also a technical problem that needs to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes an antibacterial masterbatch of a composite antibacterial agent, which, when applied in the manufacturing process of antibacterial fibers, offers advantages such as good antibacterial properties, ease of processing, and high durability. Technical solution

[0005] A PET copper antibacterial masterbatch includes a polymer resin, an antibacterial agent, and a polymer functional additive; The PET copper antibacterial masterbatch, by weight, comprises 60-80 parts of polymeric resin, 15-25 parts of antibacterial agent, and 5-15 parts of polymeric functional additives; the antibacterial agent includes copper-loaded zirconium phosphate; and the polymeric resin includes polyethylene terephthalate (PET).

[0006] The polymeric functional additives include one or more of antioxidants, heat stabilizers, white masterbatch additives, and flow improvers.

[0007] The antioxidant includes one or more of tris(2,4-dimethylphenyl) phosphite and 2,6-di(dimethylphenyl)-4-methylphenyl antioxidant; The heat stabilizer includes one or more of calcium-zinc heat stabilizers and phosphate stabilizers; The white masterbatch additive includes titanium dioxide; The flow improver includes one or more of stearic acid and polyolefin wax.

[0008] The PET copper antibacterial masterbatch also includes a reactive chain extender / compatibility agent; the reactive chain extender / compatibility agent is a multifunctional reactive polymer containing epoxy functional groups and / or oxazoline functional groups; its addition amount is 0.1% to 2.0% based on the total mass of the PET copper antibacterial masterbatch.

[0009] The reactive chain extender / compatibility agent is prepared as follows: a solvent is added to a reactor equipped with mechanical stirring, temperature detection and reflux condensation devices and inert gas protection. The temperature is raised to the polymerization temperature and held constant under inert gas protection. A monomer mixture containing vinyl aromatic monomers, acrylate monomers, methacrylate monomers and monomers containing epoxy functional groups and / or oxazoline functional groups is added dropwise to the reactor along with an initiator solution to carry out a free radical polymerization reaction. After the dropwise addition is completed, the reaction is continued at a constant temperature and then post-polymerization is carried out. After the reaction is completed, the temperature is lowered, and the copolymer melt is obtained by solvent extraction and devolatilization under vacuum conditions. The copolymer melt is extruded, cooled and pelletized to obtain reactive chain extender / compatibility agent particles.

[0010] The solvent includes ester solvents and aromatic hydrocarbon solvents; the ester solvent is selected from one or more of ethyl acetate, propyl acetate, butyl acetate, and butyl butyrate; the aromatic hydrocarbon solvent is selected from one or more of toluene and xylene. The mass ratio of the ester solvent to the aromatic hydrocarbon solvent is (2-6):1; and / or the total amount of the solvent added is 50%-150% based on the total amount of monomers. The vinyl aromatic monomers are selected from styrene and / or substituted styrene; the acrylate monomers are selected from C1 to C8 alkyl acrylates; the methacrylate monomers are selected from C1 to C8 alkyl methacrylates; the epoxy functional group-containing monomers are selected from glycidyl methacrylate and / or glycidyl acrylate; and the oxazoline functional group-containing monomers are selected from vinyl oxazoline monomers.

[0011] Based on the total amount of monomers, the vinyl aromatic monomers comprise 20%–50%, the acrylate monomers comprise 20%–50%, the methacrylate monomers comprise 10%–40%, and the monomers containing epoxy functional groups and / or oxazoline functional groups comprise 5%–20%. The initiator solution has a mass fraction of 10%–20%; the dropping time is 2–5 h; the polymerization temperature is 110–130 °C; the stirring speed is 100–500 r / min; the amount of initiator added in the subsequent polymerization is 0.05%–0.20% of the total monomer, and the subsequent polymerization time is 0.5–2.0 h; the solvent removal and devolatilization temperature is 80–110 °C; the molecular weight regulator is a C8–C16 alkyl thiol, and its addition amount is 0.05%–0.30% of the total monomer.

[0012] A method for preparing PET copper antibacterial masterbatch includes using the PET copper antibacterial masterbatch as described in any one of claims 1 to 7, and further includes: after the polymer resin is fully dried to remove moisture, it is mixed with antibacterial agent and polymer functional additive in a high-speed mixer to achieve pre-dispersion; the pre-dispersion mixture is added to the feeding device of an extruder, blended and melted, and extruded and granulated; the extruded melt is rinsed with water, cooled in air, and granulated to obtain a functional masterbatch with uniform particles.

[0013] The temperatures of each zone of the extruder include: Zone 1 (270℃-290℃), Zone 2 (270℃-290℃), Zone 3 (270℃-290℃), Zone 4 (270℃-290℃), Zone 5 (220℃-240℃), Zone 6 (220℃-240℃), Zone 7 (220℃-240℃), Zone 8 (220℃-240℃), Zone 9 (220℃-240℃), Zone 10 (230℃-240℃), Zone 11 (240℃-250℃), and Die head temperature (250℃-260℃).

[0014] The application of the aforementioned PET copper antibacterial masterbatch includes adding the prepared functional masterbatch to polyester chips for spinning functional fibers.

[0015] The beneficial effects of this invention are: The PET white copper antibacterial masterbatch and its preparation method provided by the present invention can maintain antibacterial properties while taking into account the stability of white appearance and processing stability. The obtained masterbatch particles are uniform and have good dispersibility, which is suitable for further preparation of antibacterial polyester fiber and other products. It can maintain a relatively stable antibacterial effect and appearance consistency under repeated washing or long-term use conditions.

[0016] This invention, through the synergistic design of formulation and process, enables a more uniform distribution of copper-containing antibacterial components in the PET matrix, avoiding appearance fluctuations caused by localized concentrations. Simultaneously, the combination with a white pigment system results in more stable whiteness and less color difference in the prepared white masterbatch, which is beneficial for meeting the appearance consistency requirements of white polyester fibers and their products. The masterbatch is prepared using a melt blending extrusion granulation process, which is simple and suitable for continuous, large-scale production. The combination of high-speed pre-dispersion and extrusion compounding effectively improves the dispersion state of inorganic antibacterial agents and white pigments in PET, resulting in more uniform masterbatch particle size. This leads to smaller melt fluctuations and smoother processing during subsequent blending and spinning with polyester chips, reducing breakage, clogging, and other phenomena, and improving production efficiency and finished product consistency.

[0017] This invention employs a segmented feeding method combined with a synergistic approach of metal ion passivation components, devolatilization and degassing, and chain extender / anti-hydrolysis additives to achieve a sequential suppression of the aforementioned adverse effects. Specifically, metal ion passivation components are introduced simultaneously in the early stages of the copper-containing antibacterial component entering the melt, allowing it to preferentially complex or deactivate with copper ions, reducing the ability of copper ions to participate in redox cycles and catalyze chain cleavage, thereby mitigating yellowing and color difference fluctuations in the white system and reducing the tendency of copper ions to diffuse and migrate into the PET matrix. Subsequently, moisture and volatile low-molecular-weight substances in the melt are promptly removed through a vacuum degassing section, reducing the probability of PET hydrolysis and minimizing spinning defects induced by bubbles / volatiles. Finally, chain extender / end-capping components and anti-hydrolysis components are introduced under low-water conditions, allowing the chain extender / end-capping components to react more fully with the PET molecular chain end groups (–COOH / –OH) to offset the decrease in molecular weight caused by extrusion heat history and improve melt strength and viscosity retention. The anti-hydrolysis components simultaneously capture or passivate carboxyl ends and inhibit subsequent hydrolysis, further stabilizing the processing window. Because metal ion passivation reduces the catalytic side effects of copper, devolatilization reduces the hydrolysis driving force, and the chain extension / anti-hydrolysis system repairs and locks in end groups and molecular weight, this invention can improve the yellowing / color difference of copper-containing systems, maintain the intrinsic viscosity of PET, and enhance extrusion / spinning stability without weakening the effectiveness of antibacterial components, and also improve the performance consistency during durable use. This invention introduces reactive chain extenders / compatibilizers containing epoxy and / or oxazoline functional groups. These extenders / compatibilizers react with the terminal carboxyl and / or terminal hydroxyl groups of the PET molecular chain during PET melt blending, thereby extending the chain, sealing the ends, and forming long-chain or slightly branched structures. On one hand, the reactive chain extenders / compatibilizers can "reconnect" PET chains broken under processing heat and reduce the accumulation of terminal carboxyl groups through sealing, thus reducing the tendency for autocatalytic hydrolysis initiated by terminal carboxyl groups. This improves or maintains the viscosity and strength of the PET melt, enhances the spinnability and stability of extrusion and subsequent spinning processes, and reduces problems such as pressure fluctuations, breakage, and narrowing of the process window caused by viscosity fluctuations. On the other hand, the long-branched / slightly branched structure formed after chain extension improves the viscoelasticity and interfacial coating ability of the melt, making the wetting and coating of PET melt onto copper-loaded zirconium phosphate particles and titanium dioxide particles more stable. This helps to suppress the re-aggregation of inorganic particles in high-shear flow fields and their tendency to precipitate during processing, reducing hard spots and gel defects, slowing down filtration pressure rise, and reducing the risk of spinneret blockage. As a result, the volatility of copper-containing antibacterial masterbatch during processing is reduced, and batch consistency is improved. Furthermore, the stability of the melt structure and interfacial coating state also makes the release of effective copper more gradual, which is conducive to the coordination and unity of antibacterial durability and appearance stability. Attached Figure Description

[0019] Figure 1 Photograph of the masterbatch prepared in Example 1.

[0020] Figure 2 Photograph of the antibacterial fiber prepared in Example 1. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0024] The carrier powder used in this invention is PET resin powder, grade CR-8863. Example

[0025] This embodiment provides a PET copper antibacterial masterbatch. The raw materials are weighed according to the following formula: 70 parts PET resin powder, 20 parts copper-loaded zirconium phosphate, 0.5 parts tris(2,4-dimethylphenyl) phosphite, 2 parts calcium-zinc heat stabilizer, 5 parts titanium dioxide (TiO2), and 2.5 parts stearic acid. All the above raw materials are added to a high-speed mixer and stirred for 10 minutes at a speed of 800 r / min to obtain a pre-dispersed mixture. The pre-dispersed mixture is added to the feed hopper of an extruder, with the feed rate adjusted to 12 kg / h and the extruder screw speed set to 280 rpm. The extrusion speed is r / min, and the process temperature is 280℃ for zone 1, 280℃ for zone 2, 280℃ for zone 3, 280℃ for zone 4, 230℃ for zone 5, 230℃ for zone 6, 230℃ for zone 7, 230℃ for zone 8, 230℃ for zone 9, 230℃ for zone 10, 235℃ for zone 11, and 245℃ for zone 11. The die temperature is 255℃. After extrusion, the melt is rinsed in a water bath, cooled in air, and then fed into a pelletizer to be cut into cylindrical particles with a length of 3mm ± 0.5mm and a diameter of 2.5mm ± 0.5mm, thus obtaining color masterbatch with uniform particle size. Figure 1 As shown. Example

[0026] This embodiment provides a PET copper antibacterial masterbatch. The raw materials are weighed according to the following formula: 70 parts PET resin powder, 20 parts copper-loaded zirconium phosphate, 0.5 parts 2,6-di(dimethylphenyl)-4-methylphenyl antioxidant, 2 parts phosphoric acid stabilizer, 5 parts titanium dioxide (TiO2), and 2.5 parts polyolefin wax. All the above raw materials are added to a high-speed mixer and stirred for 10 minutes at a speed of 800 r / min to obtain a pre-dispersed mixture. The pre-dispersed mixture is added to the feed hopper of an extruder, with the feed rate adjusted to 12 kg / h and the extruder screw speed set to 280 rpm. The extrusion speed is r / min, and the process temperature is 280℃ for zone 1, 280℃ for zone 2, 280℃ for zone 3, 280℃ for zone 4, 230℃ for zone 5, 230℃ for zone 6, 230℃ for zone 7, 230℃ for zone 8, 230℃ for zone 9, 235℃ for zone 10, and 245℃ for zone 11. The die head temperature is 255℃. After extrusion, the melt is rinsed in a water bath, cooled in air, and then fed into a pelletizer to be cut into cylindrical particles with a length of 3mm±0.5mm and a diameter of 2.5mm±0.5mm, thus obtaining color masterbatch with uniform particle size. Example

[0027] This embodiment provides a PET copper antibacterial masterbatch. The raw materials are weighed according to the following formula: 70 parts PET resin powder, 20 parts copper-loaded zirconium phosphate, 0.5 parts tris(2,4-dimethylphenyl) phosphite, 2 parts phosphoric acid stabilizer, 5 parts titanium dioxide (TiO2), and 2.5 parts polyolefin wax. All the above raw materials are added to a high-speed mixer and stirred for 10 minutes at a speed of 800 r / min to obtain a pre-dispersed mixture. The pre-dispersed mixture is added to the feed hopper of an extruder, with the feed rate adjusted to 12 kg / h and the extruder screw speed set to 280 rpm. The extrusion speed is r / min, and the process temperature is 280℃ for zone 1, 280℃ for zone 2, 280℃ for zone 3, 280℃ for zone 4, 230℃ for zone 5, 230℃ for zone 6, 230℃ for zone 7, 230℃ for zone 8, 230℃ for zone 9, 235℃ for zone 10, and 245℃ for zone 11. The die head temperature is 255℃. After extrusion, the melt is rinsed in a water bath, cooled in air, and then fed into a pelletizer to be cut into cylindrical particles with a length of 3mm±0.5mm and a diameter of 2.5mm±0.5mm, thus obtaining color masterbatch with uniform particle size. Example

[0028] This embodiment provides a PET copper antibacterial masterbatch. The raw materials are weighed according to the following formula: 70 parts PET resin powder, 20 parts copper-loaded zirconium phosphate, 0.5 parts 2,6-di(dimethylphenyl)-4-methylphenyl antioxidant, 2 parts calcium-zinc heat stabilizer, 5 parts titanium dioxide (TiO2), and 2.5 parts stearic acid. All the above raw materials are added to a high-speed mixer and stirred for 10 minutes at a speed of 800 r / min to obtain a pre-dispersed mixture. The pre-dispersed mixture is added to the feed hopper of an extruder, with the feed rate adjusted to 12 kg / h and the extruder screw speed set to 280 rpm. The extrusion speed is r / min, and the process temperature is 280℃ for zone 1, 280℃ for zone 2, 280℃ for zone 3, 280℃ for zone 4, 230℃ for zone 5, 230℃ for zone 6, 230℃ for zone 7, 230℃ for zone 8, 230℃ for zone 9, 235℃ for zone 10, and 245℃ for zone 11. The die head temperature is 255℃. After extrusion, the melt is rinsed in a water bath, cooled in air, and then fed into a pelletizer to be cut into cylindrical particles with a length of 3mm±0.5mm and a diameter of 2.5mm±0.5mm, thus obtaining color masterbatch with uniform particle size. Example

[0029] This embodiment is an improvement on the original embodiment 1. Except for the introduction of a reactive chain extender / compatibility agent, the other raw material types, formulation components, preparation conditions and parameters remain unchanged.

[0030] Preparation of multifunctional reactive chain extenders / compatible agents containing epoxy functional groups: In a reactor equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen protection port, 60 parts by mass of butyl butyrate and 20 parts by mass of xylene were added. After purging with nitrogen for 20-30 minutes, the temperature was raised to 115-125℃ and held constant. Separately, 35 parts by mass of styrene, 35 parts by mass of butyl acrylate, 20 parts by mass of methyl methacrylate, and 10 parts by mass of glycidyl methacrylate were mixed to obtain a monomer mixture. An initiator was prepared into a 10-20% wt solution using butyl butyrate as a diluent. A molecular weight regulator, n-dodecyl mercaptan, was added to the monomer mixture at a concentration of 0.05%-0.30% of the total monomers. At 115–125°C and a stirring speed of 150–300 r / min, the monomer mixture was added dropwise to the reactor at a uniform rate over 3 hours, while the initiator solution was added dropwise at the same rate over 3 hours. After the addition was complete, the reaction was continued at this temperature for 2.0 hours, and then 0.1% of the total monomer was added as initiator for post-polymerization over 1 hour. After the reaction was completed, the temperature was lowered to 95–100°C, and solvent extraction and devolatilization were carried out under vacuum to obtain a styrene-acrylate copolymer melt containing epoxy functional groups. The melt was then extruded using a single-screw extruder and water-cooled and pelletized to obtain multifunctional reactive chain extender / compatibilizer particles.

[0031] Weigh the raw materials according to the following formula: 70 parts PET resin powder, 20 parts copper-loaded zirconium phosphate, 0.5 parts tris(2,4-dimethylphenyl) phosphite, 2 parts calcium-zinc heat stabilizer, 5 parts titanium dioxide, 2.5 parts stearic acid, and 1.0 part reactive chain extender / compatibility agent.

[0032] All the above raw materials (including the reactive chain extender / compatibility agent) are added to a high-speed mixer and stirred for 10 minutes at a speed of 800 r / min to obtain a pre-dispersed mixture. The pre-dispersed mixture is added to the feed hopper of an extruder, with the feed rate adjusted to 12 kg / h and the extruder screw speed set to 280 r / min. The process temperature is maintained as follows: Zone 1: 280℃, Zone 2: 280℃, Zone 3: 280℃, Zone 4: 280℃, Zone 5: 230℃, Zone 6: 230℃, Zone 7: 230℃, Zone 8: 230℃, Zone 9: 230℃, Zone 10: 235℃, Zone 11: 245℃, and Die temperature: 255℃. After extrusion, the melt is rinsed in a water bath, cooled in air, and then fed into a pelletizer to be cut into cylindrical particles with a length of 3 mm ± 0.5 mm and a diameter of 2.5 mm ± 0.5 mm, thus obtaining masterbatch with uniform particle size. Example

[0033] This embodiment modifies the preparation parameters of the reactive chain extender / compatibility agent based on Example 5; the other raw material types, formulation components, and extrusion preparation conditions and parameters of the masterbatch remain consistent with those of Example 5.

[0034] Preparation of a multifunctional reactive chain extender / compatibility agent containing epoxy functional groups: In a reactor equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen protection port, 55 parts by mass of butyl butyrate and 25 parts by mass of xylene were added. After purging with nitrogen for 30 min, the temperature was raised to 120-125℃ and held constant. Separately, 35 parts by mass of styrene, 35 parts by mass of butyl acrylate, 20 parts by mass of methyl methacrylate, and 10 parts by mass of glycidyl methacrylate were mixed to obtain a monomer mixture. An initiator solution was prepared with butyl butyrate as a diluent to a concentration of 15 wt%, and a molecular weight regulator, n-dodecyl mercaptan, was added to the monomer mixture at a concentration of 0.25% of the total monomer content. At 120–125°C and a stirring speed of 250–350 r / min, the monomer mixture was added dropwise to the reactor at a uniform rate over 2.5 h, while the initiator solution was added dropwise at the same rate over 2.5 h. After the addition was complete, the reaction was continued at this temperature for 1.5 h, and then 0.15% of the total monomer amount of initiator was added for post-polymerization over 1.5 h. After the reaction was completed, the temperature was lowered to 90–95°C, and solvent extraction and devolatilization were carried out under vacuum to obtain a styrene-acrylate copolymer melt containing epoxy functional groups. The melt was extruded using a single-screw extruder and water-cooled to pelletize, yielding multifunctional reactive chain extender / compatibilizer particles.

[0035] Preparation of improved copper-containing antibacterial PET masterbatch: Weigh the raw materials according to the masterbatch formulation of Example 5, and add the above-prepared reactive chain extender / compatibility granules at 1.0 part; the remaining high-speed premixing, twin-screw extrusion temperature zone, screw speed, feeding speed and pelletizing method are the same as in Example 5. Comparative Example 1 The difference from Example 1 is that no antibacterial agent is added, the remaining white system and auxiliary agent system are consistent with Example 1, and the corresponding parts are made up with PET. The masterbatch preparation process is the same as that of Example 1; it serves as a blank sample. Comparative Example 2 The preparation process is the same as that of the reactive chain extender / compatibility in Example 5, except that the epoxy functional group monomer is replaced with an equal amount of methyl methacrylate so that the resulting copolymer does not contain functional groups that can react with PET end groups. The functional masterbatches obtained in Examples 1 to 4 were spun together with PET chips at an addition rate of 4% to produce monofilaments with a diameter of 0.35 ± 0.015 mm. The inhibition rates against *Escherichia coli*, *Staphylococcus aureus*, and *Candida albicans* were tested according to GB / T20944.3-2008 (oscillation method). The determination process for whiteness / color difference and yellowness index was as follows: L*, a*, b*, and ΔE were measured on the fiber (using a blank fiber sample as a reference), and the yellowness index YI was measured; simultaneously, heat aging (e.g., 100–120℃, 24 h, or according to the company's commonly used conditions) was performed, followed by re-measuring ΔE and YI. Filtration pressure rise and processing stability tests were conducted: a 25 μm filter of the same specification was set at the extrusion or spinning end, and the melt pressure change over time was recorded, providing the initial pressure P0, the 60-minute pressure P60, the pressure rise ΔP, and the pressure rise rate. Table 1 Summary of fiber spinning performance test results of functional masterbatches prepared in different embodiments

[0036] The above test results show that the present invention effectively improves the antibacterial ability of PET fibers by introducing antibacterial agents into the preparation formula of functional masterbatch. Under the same process conditions, the antibacterial ability of PET filaments with added antibacterial agents is greatly improved, while the antibacterial rate of blank samples without added antibacterial agents is almost zero, which is far below the industry standard.

[0037] Compared with the blank sample, the masterbatch prepared by this invention can significantly improve the antibacterial rate of PET fibers in spinning applications, thereby effectively improving the antibacterial ability of PET fibers during application. Furthermore, the color of the filament sample in the embodiment is identical to that of the blank sample. Figure 2 As shown. Compared with industry standards, the PET copper antibacterial masterbatch provided by this invention produces fibers with performance far exceeding industry standards. Furthermore, the technical route provided by this invention has a simple process in practical applications, requiring no multiple post-processing steps, which can effectively reduce production costs and energy consumption, and has significant application advantages.

[0038] Table 2 Color Difference and Yellowness

[0039] In Example 1, after adding a copper-containing antibacterial agent and a white system, ΔE and YI only increased slightly, indicating that the system can maintain good whiteness and color difference stability while satisfying antibacterial function. Example 5, compared to Example 1, showed a decrease in ΔE and b*, and a smaller increase in YI after aging, indicating that the introduction of reactive chain extenders / compatibilizers helps to further improve appearance stability. This is because such chain extenders / compatibilizers react with PET end groups during melt blending, which helps maintain melt viscosity and stable processing conditions. Simultaneously, the formed long-branched / slightly branched structure enhances the wetting, coating, and dispersion stability of copper zirconium phosphate and titanium dioxide particles, thus making color difference and yellowness more stable. Comparative Example 2, using a non-reactive compatibilizer, showed appearance indicators close to those of Example 1, further indicating that the improvement in appearance mainly comes from the synergistic effect of reactive chain extenders / end-capping with reactive functional groups and interface stability.

[0040] Table 3 Filter Pressure Rise and Defects / Broken Filter Sheets

[0041] The ΔP of Example 5 was significantly lower than that of Example 1, indicating that the introduction of reactive chain extenders / compatibility agents can significantly improve filtration stability. The chain extension / end-capping reaction helps maintain the molecular weight and melt strength of PET, improves the melt viscoelasticity and the ability to encapsulate and carry inorganic particles, thereby reducing the re-agglomeration of zirconium phosphate-loaded copper and titanium dioxide particles in the shear flow field, reducing the entry of large particles into the filtration system, resulting in a smoother pressure rise. In contrast, Comparative Example 2 showed limited improvement in ΔP when using non-reactive compatibilizers, indicating that the main contribution to the "significant reduction in pressure rise" comes from the synergistic effect of end-group reaction regulation and interface stability brought about by reactive functional groups.

Claims

1. A PET copper antibacterial masterbatch, characterized in that: This includes polymeric resins, antibacterial agents, and polymeric functional additives; The PET copper antibacterial masterbatch, by weight, comprises 60-80 parts of polymeric resin, 15-25 parts of antibacterial agent, and 5-15 parts of polymeric functional additives; the antibacterial agent includes copper-loaded zirconium phosphate; and the polymeric resin includes polyethylene terephthalate (PET).

2. The PET copper antibacterial masterbatch as described in claim 1 or 2, characterized in that: The polymeric functional additives include one or more of antioxidants, heat stabilizers, white masterbatch additives, and flow improvers.

3. The PET copper antibacterial masterbatch as described in claim 5, characterized in that: The antioxidant includes one or more of tris(2,4-dimethylphenyl) phosphite and 2,6-di(dimethylphenyl)-4-methylphenyl antioxidant; The heat stabilizer includes one or more of calcium-zinc heat stabilizers and phosphate stabilizers; The white masterbatch additive includes titanium dioxide; The flow improver includes one or more of stearic acid and polyolefin wax.

4. The PET copper antibacterial masterbatch according to any one of claims 1 to 3, characterized in that: The PET copper antibacterial masterbatch also includes a reactive chain extender / compatibility agent; the reactive chain extender / compatibility agent is a multifunctional reactive polymer containing epoxy functional groups and / or oxazoline functional groups; its addition amount is 0.1% to 2.0% based on the total mass of the PET copper antibacterial masterbatch.

5. The PET copper antibacterial masterbatch as described in claim 4, characterized in that: The reactive chain extender / compatibility agent is prepared as follows: a solvent is added to a reactor equipped with mechanical stirring, temperature detection and reflux condensation devices and inert gas protection. The temperature is raised to the polymerization temperature and held constant under inert gas protection. A monomer mixture containing vinyl aromatic monomers, acrylate monomers, methacrylate monomers and monomers containing epoxy functional groups and / or oxazoline functional groups is added dropwise to the reactor along with an initiator solution to carry out a free radical polymerization reaction. After the dropwise addition is completed, the reaction is continued at a constant temperature and then post-polymerization is carried out. After the reaction is completed, the temperature is lowered, and the copolymer melt is obtained by solvent extraction and devolatilization under vacuum conditions. The copolymer melt is extruded, cooled and pelletized to obtain reactive chain extender / compatibility agent particles.

6. The PET copper antibacterial masterbatch as described in claim 5, characterized in that: The solvent includes ester solvents and aromatic hydrocarbon solvents; the ester solvent is selected from one or more of ethyl acetate, propyl acetate, butyl acetate, and butyl butyrate; the aromatic hydrocarbon solvent is selected from one or more of toluene and xylene. The mass ratio of the ester solvent to the aromatic hydrocarbon solvent is (2-6):1; and / or the total amount of the solvent added is 50%-150% based on the total amount of monomers. The vinyl aromatic monomers are selected from styrene and / or substituted styrene; the acrylate monomers are selected from C1 to C8 alkyl acrylates; the methacrylate monomers are selected from C1 to C8 alkyl methacrylates; the epoxy functional group-containing monomers are selected from glycidyl methacrylate and / or glycidyl acrylate; and the oxazoline functional group-containing monomers are selected from vinyl oxazoline monomers.

7. The PET copper antibacterial masterbatch as described in claim 6, characterized in that: Based on the total amount of monomers, the vinyl aromatic monomers comprise 20%–50%, the acrylate monomers comprise 20%–50%, the methacrylate monomers comprise 10%–40%, and the monomers containing epoxy functional groups and / or oxazoline functional groups comprise 5%–20%. The initiator solution has a mass fraction of 10%–20%; the dropping time is 2–5 h; the polymerization temperature is 110–130 °C; the stirring speed is 100–500 r / min; the amount of initiator added in the subsequent polymerization is 0.05%–0.20% of the total monomer, and the subsequent polymerization time is 0.5–2.0 h; the solvent removal and devolatilization temperature is 80–110 °C; the molecular weight regulator is a C8–C16 alkyl thiol, and its addition amount is 0.05%–0.30% of the total monomer.

8. A method for preparing a PET copper antibacterial masterbatch, characterized in that: The method includes using the PET copper antibacterial masterbatch as described in any one of claims 1 to 7, and further includes: after the polymer resin is fully dried to remove moisture, it is mixed with the antibacterial agent and the polymer functional additive in a high-speed mixer to achieve the purpose of pre-dispersion; the pre-dispersion mixture is added to the feeding device of an extruder, blended and melted, and extruded and granulated; the extruded melt is rinsed with water, cooled in air, and granulated to obtain a functional masterbatch with uniform particles.

9. The method for preparing PET copper antibacterial masterbatch as described in claim 8, characterized in that: The temperatures of each zone of the extruder include: Zone 1 (270℃-290℃), Zone 2 (270℃-290℃), Zone 3 (270℃-290℃), Zone 4 (270℃-290℃), Zone 5 (220℃-240℃), Zone 6 (220℃-240℃), Zone 7 (220℃-240℃), Zone 8 (220℃-240℃), Zone 9 (220℃-240℃), Zone 10 (230℃-240℃), Zone 11 (240℃-250℃), and Die head temperature (250℃-260℃).

10. The application of the PET copper antibacterial masterbatch according to any one of claims 1 to 7, characterized in that: The application includes adding the prepared functional masterbatch to polyester chips to spin functional fibers.

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