TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle and its preparation technology

Abstract

This invention discloses a TiO2-ZnO composite-modified polylactic acid (PLA) functional fabric with a controllable degradation cycle and its preparation technology. The key technical points are: the TiO2-ZnO composite-modified PLA functional fabric with a controllable degradation cycle is characterized by comprising a PLA matrix, TiO2-ZnO composite modified particles, and a surface functional coating; the mass of the TiO2-ZnO composite modified particles accounts for 1-5 wt% of the mass of the PLA matrix; the TiO2-ZnO composite modified particles have a Z-shaped heterojunction structure, formed by the sol-gel method of combining anatase phase TiO2 and hexagonal wurtzite phase ZnO, with a TiO2 to ZnO mass ratio of 1:2-2:1; the surface functional coating is a silane coupling agent-modified hydrophobic coating with a thickness of 0.5-2 μm. This invention provides precise and controllable degradation cycle, adapting to various application scenarios.

Description

Technical Field

[0001] This invention relates to the field of fabric technology, and in particular to TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle and its preparation technology. Background Technology

[0002] Polylactic acid (PLA), a bio-based polymer derived from renewable resources such as corn starch, possesses excellent mechanical properties, biodegradability, and biocompatibility, making it a core alternative to petroleum-based textile materials and effectively alleviating white pollution. However, pure PLA fabrics have inherent drawbacks: First, the degradation cycle is uncontrollable. Industrial composting requires 6-12 months for complete degradation, while disposable products and medical consumables require rapid degradation (e.g., 30-60 days), and agricultural covering materials require phased, controllable degradation (e.g., 120 days during the growing season, followed by rapid degradation after harvest). Existing PLA fabrics cannot achieve customized degradation cycle matching. Second, its functionality is limited, possessing only basic biodegradability and lacking core functions such as antibacterial, UV protection, and photocatalytic self-cleaning, making it difficult to meet the needs of high-end applications. Third, its wearability is insufficient, exhibiting poor hydrophilicity and a tendency to generate static electricity. Furthermore, single modifications can easily lead to a decline in mechanical properties, limiting its large-scale application.

[0003] To address the aforementioned issues, existing technologies attempt to optimize PLA performance through single modifications: First, modification with inorganic particles such as nano-TiO2 and ZnO imparts antibacterial and UV-resistant properties to the fabric. However, single particles suffer from high photogenerated carrier recombination rates, narrow photoresponse ranges, and easy aggregation, making it difficult to balance functionality and mechanical properties, and they do not address degradation cycle regulation. Second, degradation is regulated through blending additives (such as citric acid and buffers), but this only allows for simple adjustment of the degradation rate, failing to achieve precise cycle control, and exhibits poor synergy with functional modifications. Third, individual modification using plasma or sol-gel methods is complex, has low compatibility, and makes it difficult to achieve integrated "controllable degradation + multifunctional performance."

[0004] Furthermore, existing TiO2-ZnO composite modified PLA materials mostly focus on the film or fiber level, failing to design composite systems specifically for fabric weaving characteristics and lacking a regulatory mechanism for "composite particle structure - degradation microenvironment - functional synergy." This results in uncontrolled fabric degradation cycles, insufficient functional durability, and an inability to achieve industrial mass production and scenario-specific adaptation. Therefore, developing a TiO2-ZnO composite modified PLA functional fabric with controllable degradation cycles, excellent multifunctional performance, and good wearability has become a key technological bottleneck that the industry urgently needs to overcome. Summary of the Invention

[0005] In view of the problems mentioned in the background art, the purpose of this invention is to provide a TiO2-ZnO composite modified polylactic acid functional fabric with a controllable degradation cycle and its preparation technology, so as to solve the problems mentioned in the background art.

[0006] The above-mentioned technical objective of this invention is achieved through the following technical solution: a TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle, comprising a polylactic acid matrix, TiO2-ZnO composite modified particles, and a surface functional coating; the mass of the TiO2-ZnO composite modified particles accounts for 1-5 wt% of the mass of the polylactic acid matrix; the TiO2-ZnO composite modified particles have a Z-type heterojunction structure, which is composed of anatase phase TiO2 and hexagonal wurtzite phase ZnO by a sol-gel method, and the mass ratio of TiO2 to ZnO is 1:2-2:1; the surface functional coating is a hydrophobic coating modified with a silane coupling agent, with a thickness of 0.5-2 μm.

[0007] Preferably, the polylactic acid matrix is ​​a blend of polylactic acid (PLLA) and polylactic acid-glycolic acid copolymer (PLGA), with a PLLA to PLGA mass ratio of 7:3-9:1 and a weight-average molecular weight of 8×10⁻⁶. 4 -15×10 4 The TiO2-ZnO composite modified particles have a particle size of 20-100 nm and a specific surface area of ​​50-150 m² / g.

[0008] Preferably, the degradation cycle of the fabric is controllable to be 30-180 days. Under soil composting conditions, the mass loss rate is ≥60% after 60 days of degradation and ≥90% after 120 days of degradation. The fabric has an antibacterial rate of ≥99.9% against Escherichia coli and Staphylococcus aureus, and an antibacterial rate of ≥95% after 50 washes. The UPF value is ≥50+ and the UVA transmittance is ≤1%.

[0009] This invention discloses a preparation technology for TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle, including the following steps: S1: Preparation of TiO2-ZnO composite modified particles: Titanium source and zinc source are dissolved in a mixed solvent of anhydrous ethanol and water in a certain proportion, citric acid is added as a complexing agent, the pH is adjusted to 3-5, and after sol-gel reaction, aging, drying and calcination, Z-shaped heterojunction TiO2-ZnO composite modified particles are obtained; S2: Preparation of polylactic acid masterbatch: After vacuum drying of polylactic acid matrix particles, they are mixed with TiO2-ZnO composite modified particles and surface coating agent, melt-blended and granulated by screw extruder to obtain TiO2-ZnO / PLA functional masterbatch; S3: Fiber spinning: After vacuum drying of TiO2-ZnO / PLA functional masterbatch, PLA is spun using melt spinning process. Composite fiber, spinning temperature is 170-190℃, and spinning speed is 5000-7000 m / min; S4: Weaving and surface treatment: PLA composite fiber is woven into fabric, the fabric is surface treated with low temperature plasma, and then a surface functional coating is applied by dip coating method. After drying and setting, TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle is obtained.

[0010] Preferably, in step S1, the titanium source is one or both of tetrabutyl titanate and titanium isopropoxide; the zinc source is one or both of zinc nitrate and zinc acetate; the calcination temperature is 300-500℃, and the calcination time is 2-4 h; in step S2, the surface coating agent is one or both of silane coupling agent (KH-550, KH-570) and stearic acid, and the addition amount is 5-15 wt% of the mass of the TiO2-ZnO composite modified particles; the screw speed of the screw extruder is 200-300 r / min, and the melting temperature is 160-180℃.

[0011] Preferably, in step S4, the process parameters for the low-temperature plasma treatment are: power of 100-300 W, treatment time of 5-15 min, and treatment gas of air, nitrogen, or argon; the coating solution for the surface functional coating is a 5-10 wt% silane coupling agent ethanol solution, the immersion time is 1-5 min, the drying temperature is 60-80℃, the setting temperature is 120-140℃, and the setting time is 1-3 min.

[0012] Preferably, the degradation cycle of the fabric can be controlled by adjusting the amount of TiO2-ZnO composite modified particles, the mass ratio of TiO2 to ZnO, the calcination temperature, and the thickness of the surface functional coating. When the amount of TiO2-ZnO composite modified particles added is 3-5 wt%, the mass ratio of TiO2 to ZnO is 1:1, and the calcination temperature is 400-500℃, the degradation cycle of the fabric is 30-60 days. When the amount added is 1-3 wt%, the mass ratio of TiO2 to ZnO is 1:2, and the calcination temperature is 300-400℃, the degradation cycle of the fabric is 120-180 days.

[0013] Preferably, in step S3, the cross-section of the PLA composite fiber is an irregular cross-section (trefoil shape, cross shape), the irregularity is 20-40%, and the fiber linear density is 1.1-2.2 dtex; in step S4, the fabric structure is plain weave, twill weave, honeycomb weave or a modified plain weave, and the areal density is 100-200 g / m².

[0014] Preferably, the present invention is applied to scenarios such as disposable clothing, medical dressings, agricultural covering materials, environmentally friendly home textiles, medical protective clothing, and agricultural non-woven fabrics; wherein, the disposable clothing scenario requires a fabric degradation period of 30-60 days, the medical dressing scenario requires a degradation period of 60-120 days, and the agricultural covering material scenario requires a degradation period of 120-180 days.

[0015] In summary, the present invention has the following main advantages: the degradation cycle of the present invention is precisely controllable and adaptable to various scenarios. By adjusting the heterojunction type (Z-type / II-type), content (1-5 wt%), and surface coating thickness of the TiO2-ZnO composite particles, combined with degradation triggering conditions (light / enzyme / humidity), the degradation cycle can be precisely customized.

[0016] This invention features multifunctional synergistic effects, resulting in significantly improved performance indicators. For example, in terms of antibacterial properties: TiO2-ZnO composite particles generate superoxide anions through photogenerated electron-hole pairs. hydroxyl radicals , synergistic Zn 2+ It releases substances that disrupt bacterial cell membranes, achieving an antibacterial rate of ≥99.9% against Escherichia coli and Staphylococcus aureus. Even after 50 washes, the antibacterial rate remains ≥95%, demonstrating excellent durability. Its UV resistance is also superior: the broad-spectrum absorption characteristics (200-400 nm) of the composite particles result in a UPF value ≥50+ and a UVA transmittance ≤1%, which is better than that of single TiO2 / ZnO modified fabrics. Attached Figure Description

[0017] Figure 1This is a flowchart of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] refer to Figure 1 A TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle includes a polylactic acid matrix, TiO2-ZnO composite modified particles, and a surface functional coating; the mass of the TiO2-ZnO composite modified particles accounts for 1-5 wt% of the mass of the polylactic acid matrix; the TiO2-ZnO composite modified particles have a Z-shaped heterojunction structure, which is composed of anatase phase TiO2 and hexagonal wurtzite phase ZnO through a sol-gel method, and the mass ratio of TiO2 to ZnO is 1:2-2:1; the surface functional coating is a hydrophobic coating modified with a silane coupling agent, with a thickness of 0.5-2 μm.

[0020] The polylactic acid matrix is ​​a blend of L-polylactic acid (PLLA) and polylactic acid-glycolic acid copolymer (PLGA), with a PLLA to PLGA mass ratio of 7:3-9:1 and a weight-average molecular weight of 8×10⁻⁶. 4 -15×10 4 The TiO2-ZnO composite modified particles have a particle size of 20-100 nm and a specific surface area of ​​50-150 m² / g.

[0021] The degradation cycle of the fabric is controllable from 30 to 180 days. Under soil composting conditions, the mass loss rate is ≥60% after 60 days of degradation and ≥90% after 120 days of degradation. The fabric has an antibacterial rate of ≥99.9% against Escherichia coli and Staphylococcus aureus, and an antibacterial rate of ≥95% after 50 washes. The UPF value is ≥50+ and the UVA transmittance is ≤1%.

[0022] This invention discloses a preparation technology for TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle, including the following steps: S1: Preparation of TiO2-ZnO composite modified particles: Titanium source and zinc source are dissolved in a mixed solvent of anhydrous ethanol and water in a certain proportion, citric acid is added as a complexing agent, the pH is adjusted to 3-5, and after sol-gel reaction, aging, drying and calcination, Z-shaped heterojunction TiO2-ZnO composite modified particles are obtained; S2: Preparation of polylactic acid masterbatch: After vacuum drying of polylactic acid matrix particles, they are mixed with TiO2-ZnO composite modified particles and surface coating agent, melt-blended and granulated by screw extruder to obtain TiO2-ZnO / PLA functional masterbatch; S3: Fiber spinning: After vacuum drying of TiO2-ZnO / PLA functional masterbatch, PLA is spun using melt spinning process. Composite fiber, spinning temperature is 170-190℃, and spinning speed is 5000-7000 m / min; S4: Weaving and surface treatment: PLA composite fiber is woven into fabric, the fabric is surface treated with low temperature plasma, and then a surface functional coating is applied by dip coating method. After drying and setting, TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle is obtained.

[0023] In step S1, the titanium source is one or both of tetrabutyl titanate and titanium isopropoxide; the zinc source is one or both of zinc nitrate and zinc acetate; the calcination temperature is 300-500℃ and the calcination time is 2-4 h; in step S2, the surface coating agent is one or both of silane coupling agent (KH-550, KH-570) and stearic acid, and the addition amount is 5-15 wt% of the mass of the TiO2-ZnO composite modified particles; the screw speed of the screw extruder is 200-300 r / min and the melting temperature is 160-180℃.

[0024] In step S4, the process parameters for the low-temperature plasma treatment are: power of 100-300 W, treatment time of 5-15 min, and treatment gas of air, nitrogen, or argon; the coating solution for the surface functional coating is a 5-10 wt% silane coupling agent ethanol solution, the immersion time is 1-5 min, the drying temperature is 60-80℃, the setting temperature is 120-140℃, and the setting time is 1-3 min.

[0025] The degradation cycle of the fabric can be controlled by adjusting the amount of TiO2-ZnO composite modified particles, the mass ratio of TiO2 to ZnO, the calcination temperature, and the thickness of the surface functional coating. When the amount of TiO2-ZnO composite modified particles added is 3-5 wt%, the mass ratio of TiO2 to ZnO is 1:1, and the calcination temperature is 400-500℃, the degradation cycle of the fabric is 30-60 days. When the amount added is 1-3 wt%, the mass ratio of TiO2 to ZnO is 1:2, and the calcination temperature is 300-400℃, the degradation cycle of the fabric is 120-180 days.

[0026] In step S3, the PLA composite fiber has an irregular cross-section (trilobal or cross-shaped), with an irregularity of 20-40% and a fiber linear density of 1.1-2.2 dtex; in step S4, the fabric has a plain weave, twill weave, honeycomb weave, or a modified plain weave, with an areal density of 100-200 g / m².

[0027] This invention can be applied to scenarios such as disposable clothing, medical dressings, agricultural covering materials, environmentally friendly home textiles, medical protective clothing, and agricultural non-woven fabrics. In the disposable clothing scenario, the fabric degradation period is required to be 30-60 days; in the medical dressing scenario, the degradation period is required to be 60-120 days; and in the agricultural covering material scenario, the degradation period is required to be 120-180 days.

[0028] The present invention features a precisely controllable degradation cycle, adaptable to various scenarios. By adjusting the heterojunction type (Z-type / II-type), content (1-5 wt%), and surface coating thickness of the TiO2-ZnO composite particles, combined with degradation triggering conditions (light / enzyme / humidity), the degradation cycle can be precisely customized.

[0029] This invention features multifunctional synergistic effects, resulting in significantly improved performance indicators. For example, in terms of antibacterial properties: TiO2-ZnO composite particles generate superoxide anions through photogenerated electron-hole pairs. hydroxyl radicals , synergistic Zn 2+ It releases substances that disrupt bacterial cell membranes, achieving an antibacterial rate of ≥99.9% against Escherichia coli and Staphylococcus aureus. Even after 50 washes, the antibacterial rate remains ≥95%, demonstrating excellent durability. Its UV resistance is also superior: the broad-spectrum absorption characteristics (200-400 nm) of the composite particles result in a UPF value ≥50+ and a UVA transmittance ≤1%, which is better than that of single TiO2 / ZnO modified fabrics.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle, characterized in that, The product comprises a polylactic acid (PLA) matrix, TiO2-ZnO composite modified particles, and a surface functional coating. The mass of the TiO2-ZnO composite modified particles accounts for 1-5 wt% of the mass of the PLA matrix. The TiO2-ZnO composite modified particles have a Z-type heterojunction structure and are composed of anatase TiO2 and hexagonal wurtzite ZnO through a sol-gel method, with a TiO2 to ZnO mass ratio of 1:2-2:

1. The surface functional coating is a hydrophobic coating modified with a silane coupling agent and has a thickness of 0.5-2 μm.

2. The TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle according to claim 1, characterized in that, The polylactic acid matrix is a blend of poly-L-lactic acid and poly-lactic acid-hydroxyacetic acid copolymer, the mass ratio of PLLA to PLGA is 7:3-9:1, the weight average molecular weight is 8x10 4 -15x10 4 g / mol; the particle size of the TiO2-ZnO composite modified particles is 20-100 nm, and the specific surface area is 50-150 m² / g.

3. The TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle according to claim 1, characterized in that, The degradation cycle of the fabric is controllable from 30 to 180 days. Under soil composting conditions, the mass loss rate is ≥60% after 60 days of degradation and ≥90% after 120 days of degradation. The fabric has an antibacterial rate of ≥99.9% against Escherichia coli and Staphylococcus aureus, and an antibacterial rate of ≥95% after 50 washes. The UPF value is ≥50+ and the UVA transmittance is ≤1%.

4. A preparation technology for a TiO2-ZnO composite modified polylactic acid functional fabric with a controllable degradation cycle as described in any one of claims 1-3, characterized in that, The process includes the following steps: S1: Preparation of TiO2-ZnO composite modified particles: Titanium and zinc sources are dissolved in a mixed solvent of anhydrous ethanol and water in a certain proportion. Citric acid is added as a complexing agent, and the pH is adjusted to 3-5. After sol-gel reaction, aging, drying, and calcination, Z-shaped heterojunction TiO2-ZnO composite modified particles are obtained; S2: Preparation of polylactic acid masterbatch: Polylactic acid matrix particles are vacuum dried and then mixed with TiO2-ZnO composite modified particles and surface coating agent. The mixture is melt-blended and granulated using a screw extruder to obtain TiO2-ZnO / PLA functional masterbatch; S3: Fiber spinning: After vacuum drying of TiO2-ZnO / PLA functional masterbatch, PLA composite fibers are spun using a melt spinning process. The spinning temperature is 170-190℃, and the spinning speed is 5000-7000 m / min; S4: Weaving and surface treatment: PLA... The composite fiber is woven into a fabric, and the surface of the fabric is treated with low-temperature plasma. Then, a functional coating is applied to the surface by dip coating. After drying and shaping, a TiO2-ZnO composite modified polylactic acid functional fabric with a controllable degradation cycle is obtained.

5. The preparation technique according to claim 4, characterized in that, In step S1, the titanium source is one or both of tetrabutyl titanate and titanium isopropoxide; the zinc source is one or both of zinc nitrate and zinc acetate; the calcination temperature is 300-500℃, and the calcination time is 2-4 h; in step S2, the surface coating agent is one or both of silane coupling agent and stearic acid, and the addition amount is 5-15 wt% of the mass of TiO2-ZnO composite modified particles; the screw speed of the screw extruder is 200-300 r / min, and the melting temperature is 160-180℃.

6. The preparation technique according to claim 4, characterized in that, In step S4, the process parameters for the low-temperature plasma treatment are: power of 100-300 W, treatment time of 5-15 min, and treatment gas of air, nitrogen, or argon; the coating solution for the surface functional coating is a silane coupling agent ethanol solution with a mass concentration of 5-10 wt%, the immersion time is 1-5 min, the drying temperature is 60-80℃, the setting temperature is 120-140℃, and the setting time is 1-3 min.

7. The preparation technique according to claim 4, characterized in that, The degradation cycle of the fabric can be controlled by adjusting the amount of TiO2-ZnO composite modified particles, the mass ratio of TiO2 to ZnO, the calcination temperature, and the thickness of the surface functional coating. When the amount of TiO2-ZnO composite modified particles added is 3-5 wt%, the mass ratio of TiO2 to ZnO is 1:1, and the calcination temperature is 400-500℃, the degradation cycle of the fabric is 30-60 days. When the amount added is 1-3 wt%, the mass ratio of TiO2 to ZnO is 1:2, and the calcination temperature is 300-400℃, the degradation cycle of the fabric is 120-180 days.

8. The preparation technique according to claim 4, characterized in that, In step S3, the PLA composite fiber has an irregular cross-section with an irregularity of 20-40% and a fiber linear density of 1.1-2.2 dtex; in step S4, the fabric has a plain weave, twill weave, honeycomb weave or a modified plain weave, and an areal density of 100-200 g / m².

9. The application of the TiO2-ZnO composite modified polylactic acid functional fabric with controllable degradation cycle according to any one of claims 1-3, characterized in that, It can be applied to disposable clothing, medical dressings, agricultural covering materials, environmentally friendly home textiles, medical protective clothing, agricultural non-woven fabrics and other scenarios; among them, the degradation period of the fabric is required to be 30-60 days for disposable clothing, 60-120 days for medical dressings, and 120-180 days for agricultural covering materials.

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