Plastic film material and preparation method thereof

Abstract

The invention relates to a plastic film material and a preparation method thereof, and belongs to the technical field of high polymer materials. An ethylene-vinyl acetal-itaconic anhydride terpolymer; the invention relates to silver-doped titanium dioxide modified by a titanate coupling agent. According to the preparation method, polybutylene terephthalate is taken as a matrix and is matched with the ethylene-vinyl acetal-itaconic anhydride terpolymer to serve as a regulating agent for enhancing the mechanical property and degradation property of the matrix, and meanwhile, the silver-doped titanium dioxide modified by the titanate coupling agent is combined to provide an environment-friendly photodegradation catalyst; and the plastic film material which has the characteristics of high toughness in the service period and high-efficiency degradation after being discarded is created.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a plastic film material and its preparation method. Background Technology

[0002] Polyesters, as an important class of synthetic polymers, are mainly polymerized from polybasic acids (such as diacids) and polyols (such as diols) through a polycondensation reaction. Their molecular backbone contains characteristic ester bonds (-COO-) connecting structures. Due to their diverse types, tunable properties, and ease of processing and molding, these materials are widely used in many fields. Among polyester plastics, polybutylene terephthalate (PBT) is widely used in the automotive, electronics, industrial machinery, and fiber packaging industries due to its excellent mechanical properties, abrasion resistance, solvent resistance, and processing performance.

[0003] In recent years, with the increasing demand for sustainable development, the demand for plastic degradation has been increasing. PBT, as a typical engineering plastic, was originally designed to meet the requirements of harsh operating environments and long service life, which results in its extremely slow degradation rate in the natural environment.

[0004] In existing technologies, although biodegradable polyesters can biodegrade under specific conditions, their mechanical properties (such as strength and toughness) often fail to meet requirements. While photodegradable additives can accelerate the disintegration of plastics under specific conditions, they typically suffer from incomplete degradation, accelerated performance decline, and reduced service life. Summary of the Invention In view of the above situation and to overcome at least some of the defects of the prior art, the present invention provides a plastic film material and a method for preparing the same.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a plastic film material comprising the following components: Polybutylene terephthalate; Ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer; Silver-doped titanium dioxide modified with titanate coupling agent.

[0006] In some embodiments of the present invention, the mass ratio of the polybutylene terephthalate to the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is 10:(3-6).

[0007] In some embodiments of the present invention, the mass ratio of the polybutylene terephthalate to the silver-doped titanium dioxide modified by the titanate coupling agent is 100:(1-5).

[0008] In some embodiments of the present invention, the amount of silver doping in the titanate coupling agent modified silver-doped titanium dioxide is 0.5-3 wt%.

[0009] A second aspect of the present invention provides a method for preparing a plastic film material, comprising the following steps: After vacuum drying, polybutylene terephthalate and ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer are premixed with silver-doped titanium dioxide modified with titanate coupling agent at a mass ratio, heated to 200-250℃ for melt blending, and then extruded and blow-molded to obtain plastic film material.

[0010] In some embodiments of the present invention, the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is synthesized through the following steps: S1, ethylene-vinyl acetate copolymer is hydrolyzed in NaOH / methanol solution at 70-80℃ for 3-5h to obtain ethylene-vinyl alcohol copolymer; S2. In anhydrous dimethyl sulfoxide, using p-toluenesulfonic acid as a catalyst, ethylene-vinyl alcohol copolymer and aldehydes are acetalized at 80-85℃ for 4-8 hours to obtain acetalized polymer. S3. In anhydrous dimethyl sulfoxide, the acetalized polymer and itaconic anhydride are esterified at 85-95℃ for 10-15 h to obtain an ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer.

[0011] In some embodiments of the present invention, in step S2, the aldehyde is selected from formaldehyde, acetaldehyde, butyraldehyde, octanaldehyde or benzaldehyde, and the mass ratio of the ethylene-vinyl alcohol copolymer to the aldehyde is 10:(2-5).

[0012] In some embodiments of the present invention, in step S3, the mass ratio of the acetalized polymer to itaconic anhydride is 10:(3-6).

[0013] In some embodiments of the present invention, the titanate coupling agent modified silver-doped titanium dioxide is synthesized through the following steps: After mixing tetrabutyl titanate with anhydrous ethanol, the pH value was adjusted to 2-3, silver nitrate was added, and the mixture was stirred for 20-30 minutes to obtain a sol. The sol was aged at room temperature for 20-30 hours, dried, and then calcined in a muffle furnace at 400-450℃ for 3-5 hours to obtain silver-doped titanium dioxide. Silver-doped titanium dioxide was dispersed in anhydrous ethanol, sonicated for 20-30 min, then a titanate coupling agent was added, and the mixture was stirred at 60-80℃ for 2-3 h. After centrifugation and drying, silver-doped titanium dioxide modified with titanate coupling agent was obtained.

[0014] In some embodiments of the present invention, the mass ratio of the titanate coupling agent to silver-doped titanium dioxide is 100:(0.5-2), and the titanate coupling agent is tetraisopropyl di(dioctyl phosphite) titanate or tetraisopropyl (dilauryl phosphite) titanate.

[0015] The beneficial effects achieved by this invention are as follows: This invention uses polybutylene terephthalate as the matrix, combined with ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer as a regulator to enhance the mechanical and degradation properties of the matrix. At the same time, it combines silver-doped titanium dioxide modified with titanate coupling agent to provide an environmentally friendly photodegradation catalyst. The three work synergistically to create a plastic film material that has both high strength and toughness during service life and high degradability after disposal. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] To address the shortcomings of the prior art mentioned in the background section, the first aspect of this invention provides a plastic film material comprising the following components: Polybutylene terephthalate; Ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer; Silver-doped titanium dioxide modified with titanate coupling agent.

[0020] First, the plastic film material uses polybutylene terephthalate (PBT) as the polymer matrix, which can endow the film with the necessary mechanical strength, heat resistance and dimensional stability. Its crystallization characteristics in the blend system provide a basic support skeleton for the film, meeting the basic mechanical properties required for the use of the film.

[0021] Secondly, in the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer, the ethylene-vinyl alcohol copolymer can provide high barrier properties. The acetal group introduced by the reaction of aldehydes (such as butyraldehyde) with the hydroxyl groups of ethylene-vinyl alcohol can provide better flexibility to the ethylene-vinyl alcohol copolymer and improve the compatibility between ethylene-vinyl alcohol and PBT, thus facilitating their blending. Further grafting itaconic anhydride onto the acetalized backbone can introduce carboxyl groups and unsaturated double bonds into the copolymer. The carboxyl groups can undergo transesterification with the hydroxyl groups of PBT. This strong interfacial bonding and good compatibility can improve the tensile strength and toughness of the film. The unsaturated double bonds are prone to generate free radicals under ultraviolet light, initiating oxidative chain scission of PBT chains. When the blend system contains a photocatalyst (such as silver-doped titanium dioxide), the double bonds can enhance the efficiency of photogenerated electron transfer, increase the production of reactive oxygen species, and accelerate the oxidative degradation of the PBT main chain, thereby enhancing the degradation efficiency of PBT.

[0022] Titanium dioxide is a broad-spectrum photocatalyst. Doping with silver can broaden the light absorption range of titanium dioxide, making it more efficient in responding to visible light and enhancing its catalytic efficiency. Under light irradiation, silver-doped titanium dioxide generates photogenerated electrons and holes. These strong redox particles can directly attack the surrounding polymer, causing oxidative chain breakage and reducing the molecular weight, which significantly improves the efficiency of subsequent biodegradation. Modifying silver-doped titanium dioxide with titanate coupling agents can, on the one hand, transform its hydrophilic surface into an oleophilic one, greatly improving its polarity and compatibility with the polymer matrix, and on the other hand, prevent particle agglomeration, allowing it to be uniformly dispersed in the matrix during melt blending.

[0023] In summary, this invention uses polybutylene terephthalate as the matrix, combined with ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer as a regulator to enhance the mechanical and degradation properties of the matrix, and combines it with silver-doped titanium dioxide modified with titanate coupling agent to provide an environmentally friendly photodegradation catalyst. The three work synergistically to create a plastic film material that combines high strength and toughness during service life with efficient degradation after disposal.

[0024] In some embodiments, the mass ratio of polybutylene terephthalate (PBPT) to ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is 10:(3-6). If the ratio of PBPT to ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is too small, the mechanical properties of the plastic film will be unbalanced; if the terpolymer phase is excessive, it will disrupt the continuous phase structure of PBT. When the ratio is less than 10:6, the tensile strength of the plastic film decreases significantly; when the ratio of polybutylene terephthalate to ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is too large, its toughening effect is insufficient, and the degradation efficiency of the plastic film is low. When the ratio is greater than 10:3, the degradation efficiency of the plastic film is too low.

[0025] In some embodiments, the mass ratio of polybutylene terephthalate (PBTB) to silver-doped titanium dioxide modified with a titanate coupling agent is 100:(1-5). If the ratio is too small, the aggregation of nanoparticles will lead to a decrease in the performance of the plastic film; when the ratio is less than 100:5, the impact strength of the plastic film will decrease significantly. If the ratio is too large, the photocatalyst cannot form a continuous permeation network in the polymer, resulting in low photocatalytic degradation efficiency; when the ratio is greater than 100:1, the photocatalytic degradation efficiency cannot meet the requirements.

[0026] In some embodiments, the silver doping amount in the titanate coupling agent-modified silver-doped titanium dioxide is 0.5-3 wt%. Silver doping forms impurity energy levels in the TiO2 lattice, effectively narrowing the band gap of TiO2. Too low a silver content (<0.5 wt%) is insufficient to form a continuous impurity band, resulting in limited absorption of visible light and reduced photogenerated carriers (ep). - / h + Insufficient concentration increase results in weak catalytic activity gain; excessively high silver content (>3wt%) leads to excessive aggregation of silver particles on the TiO2 surface, forming large-sized silver clusters instead of atomic-level dispersion, which become recombination centers for electron-hole pairs and reduce quantum efficiency.

[0027] The second aspect of the present invention provides a method for preparing a plastic film material, comprising the following steps: vacuum drying of polybutylene terephthalate and ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer, premixing with silver-doped titanium dioxide modified with titanate coupling agent at a mass ratio, melting and blending at 200-250°C, and obtaining the plastic film material by extrusion and blow molding.

[0028] By premixing dried polybutylene terephthalate, ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer, and silver-doped titanium dioxide modified with titanate coupling agent in a low-speed mixer, primary dispersion of the filler can be achieved, reducing the difficulty of subsequent melt blending. Melt blending at 200-250℃ allows the carboxyl groups of the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer to undergo esterification with the hydroxyl groups of polybutylene terephthalate, significantly enhancing the interfacial bonding between the two phases.

[0029] In some embodiments, the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is synthesized through the following steps: S1, ethylene-vinyl acetate copolymer is hydrolyzed in NaOH / methanol solution at 70-80℃ for 3-5h to obtain ethylene-vinyl alcohol copolymer; S2. In anhydrous dimethyl sulfoxide, using p-toluenesulfonic acid as a catalyst, ethylene-vinyl alcohol copolymer and aldehydes are acetalized at 80-85℃ for 4-8 hours to obtain acetalized polymer. S3. In anhydrous dimethyl sulfoxide, the acetalized polymer and itaconic anhydride are esterified at 85-95℃ for 10-15 h to obtain an ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer.

[0030] In step S1, a high-hydroxyl-content ethylene-vinyl alcohol copolymer can be mildly prepared by hydrolyzing acetate groups in a methanol / NaOH system at 70-80℃, providing sufficient active sites for subsequent acetalization. In step S2, aldehyde-alcohol condensation is selectively promoted in anhydrous DMSO solvent system at 80-85℃, and the degree of acetalization can be controlled at 25-35% after 4-8 hours of reaction, which introduces sufficient hydrolyzable acetal bonds while retaining 30-40% free hydroxyl groups for grafting in the third step. In step S3, itaconic anhydride is side-linked by esterification reaction in anhydrous DMSO solvent system, introducing carboxyl groups and unsaturated double bonds into the copolymer.

[0031] In some embodiments, in step S2, the aldehyde is selected from formaldehyde, acetaldehyde, butyraldehyde, octanaldehyde, or benzaldehyde, and the mass ratio of the ethylene-vinyl alcohol copolymer to the aldehyde is 10:(2-5). Setting the mass ratio of the ethylene-vinyl alcohol copolymer to the aldehyde to 10:(2-5) can control the degree of acetalization to 25-35%, which introduces sufficient hydrolyzable acetal bonds while retaining 30-40% free hydroxyl groups for grafting in the third step.

[0032] In some embodiments, in step S3, the mass ratio of the acetalized polymer to itaconic anhydride is 10:(3-6). Setting the mass ratio of the acetalized polymer to itaconic anhydride to 10:(3-6) ensures sufficient reaction driving force while avoiding the accumulation of anhydride hydrolysis byproducts.

[0033] In some embodiments, the titanate coupling agent-modified silver-doped titanium dioxide is synthesized through the following steps: tetrabutyl titanate is mixed with anhydrous ethanol, the pH is adjusted to 2-3, silver nitrate is added, and the mixture is stirred for 20-30 min to obtain a sol. The sol is aged at room temperature for 20-30 h, dried, and then calcined in a muffle furnace at 400-450 °C for 3-5 h to obtain silver-doped titanium dioxide. The silver-doped titanium dioxide is dispersed in anhydrous ethanol, sonicated for 20-30 min, a titanate coupling agent is added, and the mixture is stirred at 60-80 °C for 2-3 h. After centrifugation and drying, the titanate coupling agent-modified silver-doped titanium dioxide is obtained.

[0034] Silver-doped titanium dioxide was prepared by sol-gel method using tetrabutyl titanate and silver nitrate as raw materials. Then, the silver-doped titanium dioxide was dispersed in anhydrous ethanol and reacted with titanate coupling agent to further improve its dispersibility and compatibility.

[0035] In some embodiments, the mass ratio of the titanate coupling agent to silver-doped titanium dioxide is 100:(0.5-2), and the titanate coupling agent is tetraisopropyl di(dioctyl phosphite) titanate or tetraisopropyl (dilauryl phosphite) titanate. By setting the mass ratio of the titanate coupling agent to silver-doped titanium dioxide to 100:(0.5-2), the silver-doped titanium dioxide can have better dispersibility and compatibility, while avoiding affecting its photocatalytic effect.

[0036] The present invention will be further described below by way of specific embodiments.

[0037] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods already existing in the art; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels.

[0038] Example 1: The ethylene-vinyl acetate copolymer was hydrolyzed in a 10% NaOH / methanol solution at 70°C for 3 hours to obtain an ethylene-vinyl alcohol copolymer. In anhydrous dimethyl sulfoxide, using p-toluenesulfonic acid as a catalyst, ethylene-vinyl alcohol copolymer and butyraldehyde were acetalized at 80°C for 4 hours at a mass ratio of 10:2 to obtain an acetalized polymer. In anhydrous dimethyl sulfoxide, the acetalized polymer and itaconic anhydride were esterified at 85°C for 10 h in a mass ratio of 10:3 to obtain an ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer. Tetrabutyl titanate was mixed with anhydrous ethanol, the pH was adjusted to 2, silver nitrate was added, and the mixture was stirred for 20 min to obtain a sol. The sol was aged at room temperature for 20 h, dried, and then calcined in a muffle furnace at 400 °C for 3 h to obtain silver-doped titanium dioxide. Silver-doped titanium dioxide was dispersed in anhydrous ethanol and sonicated for 20 min. Then, tetraisopropyl di(dioctyl phosphite) titanate, a titanate coupling agent, was added. The mass ratio of titanate coupling agent to silver-doped titanium dioxide was 100:0.5. The mixture was stirred at 60 °C for 2 h, centrifuged, and dried to obtain silver-doped titanium dioxide modified with titanate coupling agent. After vacuum drying, polybutylene terephthalate and ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer were premixed with silver-doped titanium dioxide modified with titanate coupling agent at a mass ratio of 100:30:1. The mixture was then melt-blended at 200°C and extruded and blow-molded to obtain a plastic film material.

[0039] Example 2: The ethylene-vinyl acetate copolymer was hydrolyzed in a 10% NaOH / methanol solution at 80°C for 5 hours to obtain an ethylene-vinyl alcohol copolymer. In anhydrous dimethyl sulfoxide, using p-toluenesulfonic acid as a catalyst, ethylene-vinyl alcohol copolymer and formaldehyde were acetalized at 85°C for 8 hours at a mass ratio of 10:5 to obtain an acetalized polymer. In anhydrous dimethyl sulfoxide, the acetalized polymer and itaconic anhydride were esterified at 95°C for 15 h in a mass ratio of 10:6 to obtain an ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer. Tetrabutyl titanate was mixed with anhydrous ethanol, the pH was adjusted to 3, silver nitrate was added, and the mixture was stirred for 30 min to obtain a sol. The sol was aged at room temperature for 30 h, dried, and then calcined in a muffle furnace at 450 °C for 5 h to obtain silver-doped titanium dioxide. Silver-doped titanium dioxide was dispersed in anhydrous ethanol and sonicated for 30 min. Then, tetraisopropyl (dilauryl phosphite) titanate, a titanate coupling agent, was added. The mass ratio of titanate coupling agent to silver-doped titanium dioxide was 100:2. The mixture was stirred at 80 °C for 3 h, centrifuged, and dried to obtain silver-doped titanium dioxide modified with titanate coupling agent. After vacuum drying, polybutylene terephthalate and ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer were premixed with silver-doped titanium dioxide modified with titanate coupling agent at a mass ratio of 100:60:5. The mixture was then melt-blended at 250°C and obtained as a plastic film material through extrusion and blow molding.

[0040] Example 3: Consistent with Example 1, except that in the plastic film material, the mass ratio of polybutylene terephthalate, ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer and silver-doped titanium dioxide modified with titanate coupling agent is 100:40:2.

[0041] Example 4: Consistent with Example 1, except that in the plastic film material, the mass ratio of polybutylene terephthalate, ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer and silver-doped titanium dioxide modified with titanate coupling agent is 100:45:3.

[0042] Example 5: Consistent with Example 1, except that in the cured adhesive, the mass ratio of polybutylene terephthalate, ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer and silver-doped titanium dioxide modified with titanate coupling agent is 100:50:4.

[0043] Comparative Example 1: Consistent with Example 1, except that the plastic film material does not include the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer.

[0044] Comparative Example 2: Consistent with Example 1, except that the plastic film material does not include silver-doped titanium dioxide modified with titanate coupling agent.

[0045] Tests were conducted on Examples 1-5 and Comparative Examples 1 and 2. The specific test contents are as follows: Degradation performance test: Cut a 100×100mm film sample and place it in a xenon lamp aging chamber (Q-SUNXe-3-HS). The parameters were set as follows: irradiation intensity: 0.55W / m²@340nm, black mark temperature: 60℃±2℃, cycle program: 180min irradiation + 30min deionized water spray, cycle for 28 days. After the experiment, collect the remaining product, wash with deionized water 3-5 times, and vacuum dry at 60℃ for 24h. Calculate the weight loss of the film sample: Weight loss = (M0 - M...) 48 ) / M0×100%.

[0046] Tensile property test: The film was precisely cut using a dumbbell cutter (total length 150mm, gauge length 50×10mm). The thickness was measured at 5 points on the gauge length using a laser thickness gauge to ensure a thickness of 0.025±0.002mm. The sample was placed in a constant temperature and humidity chamber (23±0.5℃, 50%±5%RH) for 48 hours to eliminate the influence of temperature and humidity. A universal testing machine (Instron 5967) was used with a clamping distance of 100mm and a tensile rate of 50±1mm / min. The machine was started and the clamps separated at a constant speed. Tensile force was applied to the sample until it broke, and the tensile strength was recorded.

[0047] Impact resistance test: Referring to GB / T 9639.1-2008, the pendulum impact method is adopted. A strip-shaped specimen (≥60×60mm) is cut, clamped in the specimen fixture, and the pendulum is released to impact the center of the specimen. The energy absorbed during fracture is recorded, and the impact strength per unit thickness is calculated.

[0048] The test results are shown in Table 1.

[0049] Table 1

[0050] Referring to the degradation performance test in Table 1, the weight loss of Examples 1-5 was greater than 35%, which was a significant improvement compared to Comparative Examples 1 and 2. This indicates that the addition of ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer and silver-doped titanium dioxide modified with titanate coupling agent can improve the degradability of plastic film materials. In particular, the addition of silver-doped titanium dioxide modified with titanate coupling agent can significantly enhance the degradability of plastic film materials.

[0051] Referring to the tensile strength test in Table 1, the tensile strength of Examples 1-5 is greater than that of Comparative Examples 1 and 2. Among them, the tensile strength of Example 1 is significantly higher than that of Comparative Example 1, indicating that the addition of the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer can greatly enhance the tensile strength of the plastic film material.

[0052] Referring to the impact strength test in Table 1, the impact strength of Examples 1-5 is greater than that of Comparative Examples 1 and 2. Among them, the sum of the impact strength of Example 1 and Comparative Example 1 shows a significant increase, indicating that the addition of the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer can also greatly enhance the impact strength of the plastic film material.

[0053] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0054] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A plastic film material, characterized in that, Includes the following components: Polybutylene terephthalate; Ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer; Silver-doped titanium dioxide modified with titanate coupling agent.

2. The plastic film material according to claim 1, characterized in that, The mass ratio of the polybutylene terephthalate to the ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is 10:(3-6).

3. The plastic film material according to claim 1, characterized in that, The mass ratio of polybutylene terephthalate to silver-doped titanium dioxide modified with titanate coupling agent is 100:(1-5).

4. The preparation method according to claim 1, characterized in that, In the silver-doped titanium dioxide modified with the titanate coupling agent, the amount of silver doping is 0.5-3 wt%.

5. A method for preparing a plastic film material according to any one of claims 1-4, characterized in that, Includes the following steps: After vacuum drying, polybutylene terephthalate and ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer are premixed with silver-doped titanium dioxide modified with titanate coupling agent at a mass ratio, heated to 200-250℃ for melt blending, and then extruded and blow-molded to obtain plastic film material.

6. The method according to claim 5, characterized in that, The ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer is synthesized through the following steps: S1, ethylene-vinyl acetate copolymer is hydrolyzed in NaOH / methanol solution at 70-80℃ for 3-5h to obtain ethylene-vinyl alcohol copolymer; S2. In anhydrous dimethyl sulfoxide, using p-toluenesulfonic acid as a catalyst, ethylene-vinyl alcohol copolymer and aldehydes are acetalized at 80-85℃ for 4-8 hours to obtain acetalized polymer. S3. In anhydrous dimethyl sulfoxide, the acetalized polymer and itaconic anhydride are esterified at 85-95℃ for 10-15 h to obtain an ethylene-vinyl alcohol acetal-itaconic anhydride terpolymer.

7. The method according to claim 6, characterized in that, In step S2, the aldehyde is selected from formaldehyde, acetaldehyde, butyraldehyde, octanaldehyde or benzaldehyde, and the mass ratio of the ethylene-vinyl alcohol copolymer to the aldehyde is 10:(2-5).

8. The method according to claim 6, characterized in that, In step S3, the mass ratio of the acetalized polymer to itaconic anhydride is 10:(3-6).

9. The method according to claim 5, characterized in that, The titanate coupling agent-modified silver-doped titanium dioxide is synthesized through the following steps: After mixing tetrabutyl titanate with anhydrous ethanol, the pH value was adjusted to 2-3, silver nitrate was added, and the mixture was stirred for 20-30 minutes to obtain a sol. The sol was aged at room temperature for 20-30 hours, dried, and then calcined in a muffle furnace at 400-450℃ for 3-5 hours to obtain silver-doped titanium dioxide. Silver-doped titanium dioxide was dispersed in anhydrous ethanol, sonicated for 20-30 min, then a titanate coupling agent was added, and the mixture was stirred at 60-80℃ for 2-3 h. After centrifugation and drying, silver-doped titanium dioxide modified with titanate coupling agent was obtained.

10. The method according to claim 9, characterized in that, The mass ratio of the titanate coupling agent to silver-doped titanium dioxide is 100:(0.5-2), and the titanate coupling agent is tetraisopropyl di(dioctyl phosphite) titanate or tetraisopropyl dilaurylate (diisopropyl phosphite) titanate.

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